I'm just a space nerd, all the below is conjecture.
Lots of talk about refueling even with the 20 year lifespan, from what I've gathered having watched a lot of the NASA conferences and livestreams this past year, with this amount of operational fuel capacity the problem in 20 years will be on operational lifetime of wear components, not just the fuel.
The reaction wheels are _large_ moving parts on the JWST. The cryocooler for the MIRI is a very finely calibrated moving part. It's a closed system, but still relies on pumps and electronics. After 2 decades of operation it's very likely that these will be experiencing some issues.
While in 2 decades it might be feasible to refuel the JWST, it seems very unlikely it'd be worth it given the operational wear of every other component. Had we used too much fuel to correct the course to get where we are the math may have been very different. Seems to me that we're fortunate that we can instead dedicate resources to the next-gen observatories!
With SpaceX Starship the space industry is going to be very different in 20 years time. Launching new telescopes, even larger ones, will be much easer.
Attempts to refuel will be completely unneeded.
Edit:
This seems to be a controversial opinion (based on down votes). To clarify, my expectation is that if launch costs have come down as much as people suggest, launching a new and improved (potentially significantly larger) space telescope would be a better use of funds than a complicated and risky refuelling mission. There will be many lessons learnt from JWST that by then there will be an appetite for something new.
My hope also is that if the cost to launch has come down so would the development costs of any new satellites, leading to reduced costs for science missions.
I suspect you're being excessively dinged for the absolute statement that refueling will be completely unneeded.
It's fair to say that over two decades, additional capabilities will exist.
Given the advances in launch systems, both in situ assembly (large structures w/o complex packaging and deployments), and planned servicing and replaceability could mean that both arguments are true:
- We'll have bigger, more capable, and/or simply more observatories.
- Those themselves will be capable of being serviced and upgraded over their own lifetimes.
Keep in mind that one element of science that's advanced by such projects is engineering systems for space environments themselves. Vacuum, radiation, micrometeorites, station-keeping, gravitational flux and variance, materials handling (cold-welding, lubrcation, moving parts, etc.), thermal management, and design-for-servicing itself, all factor in to considerations.
It seems highly probable to me that any such servicing itself will all but certainly be robotic. At L2, speed-of-light issues are a factor as there is a one-way signal time of five seconds, long enough that direct control of physical manipulators is no longer feasible, or very slow. (Imagine that you reach for a wrench, and ten seconds later, see that your hand has actually extended and contacted it.) And putting humans in such a location, only reachable over many days or weeks, well out of Earth's magnetosphere radiation projection, would be fantastically expensive.
In 20 years we might be able to spamcraft a bunch of ~3m space telescopes and be able to measure their positions with sufficient precision to enable long baseline interferometry in the IR and optical spectrum. We might never build this large of a single instrument again.
The larger the aperture, the smaller the resolved object that we can look at. For example, looking at the central black hole of M87 which is on the order of "diameter of the solar system" ( https://xkcd.com/2135/ ).
However, the only reason we are able to resolve it is that it is so bright.
The Green Bank Telescope 100m and the Effelsberg 100m telescopes are much more sensitive than the VLA... but the VLA can resolve 0.2 and 0.04 overall.
So yes, we could send up a bunch of 3m space telescopes out to the L2 point - but how many individual miniature instruments are we going to need to make for each, how much propellant will be needed for each, how will you keep the cold side cold (size matters)?
While I'm not a rocket scientist, I'm not sure that those are easy problems to solve... and I feel like they're much harder problems to solve than ones that the JWST and the current line of telescope proposals have.
>the absolute statement that refueling will be completely unneeded.
>It's fair to say that over two decades, additional capabilities will exist.
Capability doesn't create need, in either a technical or economic/resources sense.
Too many people are interpreting "unneeded" as: "a satisfactory amount of fuel for a long-enough lifespan, but more would be better"...
When it really means: "fuel is no longer the most likely controlling/ limiting factor as to what ultimately triggers the end of webb's usable/useful lifespan".
Even if fuel ends up being the actual limiting factor, no ability to extend the (likely) lifespan of ALL the other critical components makes refueling a high-risk, high-cost, low-return venture.
> Capability doesn't create need, in either a technical or economic/resources sense.
Of course it does! Today we have all kinds of needs that people 20, 100, 1000 years did not have. That's because the capability to do something created the need for it.
For an obvious example, people need iphones. Nobody had one 20 years ago.
For another, deodorant wasn't needed 100 years ago. The need for it was totally created by the ability to manufacture it.
Capability allows the market to exist and creates potential for demand.
For certain levels of actual demand and saturation, social/cultural normalcy and expectations might lead to "need" as you describe it.
But in this case, I meant specifically that Webb, given 20 yrs of remaining fuel, won't suddenly "need" refueling if the experimental technology suddenly becomes avaliable in 19 years, as the remaining system also approaches end of life.
Fuel is no longer the most likely point of failure for determining lifespan. That might have been different if Webb had to use more fuel on its trajectory burn, had only a few years of fuel, and the technology was extant/eminent and cheap.
The risk-v-reward calculus would completely different, but unlikely to change at this point.
If my truck throws a rod on a roadtrip in Alaska and I limp upon a gas station as my 20yo dying truck burns the last of its gasoline... I don't "need" gasoline, I need a flight home and a new truck.
So, I agree that there are likely multiple paths to end-of-mission for JWST.
And that fuel itself, over 20 years, could prove not to be the limiting factor.
There remains the point that you've stated, and are again asserting, an absolute condition, that refueling is completely unneeded. Given that a now + 20 years JWST that is still functional except for fuel might exist, that categorical absolute remains unjustified, regardless of how probable it might be. And again, it's specifically how you're communicating this that seems to be raising objections.
None of us have a perfect view of the future. JWST itself offers only an improved view of the past, after all.
If refueling was already a highly questionable proposition given 5 or 10 years of fuel, having ~20 years of fuel certainly doesn't increase the reward in risk-vs-reward analysis.[0]
In what hypothetical scenario does fuel deplete at a greater than expected rate, in a way that wouldn't also call into question the reliability and expected lifespan of the remaining limiting factors?
Accidental commanded release? A leak? Station-keeping being more demanding than expected? Those would all move risk-v-reward in the wrong direction.
And it doesn't substantially decrease the cost or risks, other than what might be gained by an extended development period, which would need to be weighed against simultaneous advances better applied to and spent on a successor.
So maybe not an absolutism, but an already highly-unlikely proposition who's chances of implementation just decreased dramatically due to the new information at hand.
[0] By ending up with an older/ closer to failure but refueled satellite, and a decreased relative value of remaining potential science/observations, presuming highest value science is done first.
They are not the elements of your initial nor follow-up comments with which I've had issue. And you continue to not address those.
As for what might lead to low-fuel-but-serviceable observatory: reaction-wheel degreadation shy of failure (there are multiple redundant wheels for each axis of rotation), possibly some kind of solar-storm or solar-wind interaction which increases station-keeping requirements.
It's difficult to foresee what previously anticipated scenarios might emerge, for all the obvious reasons. But if I had a $10 billion low-on-fuel observatory on my hands, it was still turning in good science, and my capabilities to provide it with fuel had improved markedly, and there was nothing else obviously imminantly limiting lifetime ... I might opt for the top-up. Even at a cost of a few sheckles.
Keep in mind that the opportunity cost isn't the amortised value of the observatory, but its projected future life and the cost of replacing that functionality. I don't know what the associated values here are. I could envision a reality in which those turned favourable for a refueling mission.
Which, again, contradicts your original, and several-times-sustained, "completely unneeded" assertion.
The horse seems quiet well flogged, and in the interests of a peaceful death, I'm begging off further beating of it.
I’m not sure if the launch cost was a driving factor in JWST’s price tag. Granted a lot of the engineering was constrained around how to deal with the massive forces involved in launch but I suspect those forces will still be in play with starship.
Yeah you might be able to get bigger and heavier but it still needs to contend with launch forces.
Now assembling it in space might change things… but I’m sure that has its own challenges. And even then you’d probably want a space elevator instead of rockets to get your people and equipment int local orbit.
I think the idea is that if the launch cost is so much lower you can take more risk with the design as you can more easily justify launching again or take a more iterative design approach.
The Arian 5 costs around $185M to launch, they therefore need to make sure it works first time.
JWST, like all things in space, has all sorts of complications caused by the launcher.
Size constraints are particularly obvious. For instance, it's 6.5M diameter mirror needed to fold up for launch to fit inside the less than 5.4M diameter fairing. That would fit comfortably without folding in Starships 9M diameter. The sunshield wouldn't quite fit unfolded (14m x 29m), but you can almost guarantee that it would have had a simpler deployment mechanism.
Mass constraints are maybe more important, but less obvious. JWST weighs 6161 kg, Starship is aiming for a payload of more like 100,0000 kg, and by taking advantage of orbital refuelling the capability to put that anywhere instead of it being severely reduced past LEO. That means you can use heavier mirrors instead of optimizing them for weight, you can build your structures out of easy to work with materials light metal, instead of hard to work with ones like carbon fiber. You can oversize parts, and include redundant ones if you think they might be needed.
Even if you totally ignored the cost of the launch, the capabilities of a super heavy launcher would make a huge difference. The cost is the icing on the top. It means that as long as you can build a second version for substantially cheaper than the first, you don't have to design the first so that it never fails. For instance, you don't have to design your heatshield on earth and never test the design in 0G until it's on your 10 billion dollar satellite that has to work...
The question is how much of that cost was involved in getting it to fit the launch constraints? The materials chosen, the unfolding method, etc. On top of all of that, it has to be made so that it absolutely cannot fail.
Imagine instead launching components that could be docked together in orbit, tested, and then boosted to it's destination orbit.
If you were making the same thing at the same time, it'd be about 30%. That is, previous space missions that have built 2 flight articles have spent about 30% more.
Doing it after the fact--- some design work would be saved, but how much of the tooling and supply chain still exists? Parts are going to need re-engineering, etc.
> I think the idea is that if the launch cost is so much lower you can take more risk with the design as you can more easily justify launching again or take a more iterative design approach.
You can also remove large categories of risk by freely spending mass and volume.
> Starship is estimated to be $2-10M.
Don't believe the hype. If Starship works out, they can beat other paths to orbit by a fair margin, but it's not going to be a >10x reduction. Much likely much less than that, too.
The launch costs weren't a driving factor but the launch restrictions made the engineering costs a driving factor.
There should never be such an expensive program again because hopefully we'd realize its easier to also build a massive 1-off rocket for it instead of years developing awesome folding things. Has all the money SpaceX have ever spent so far even come to 10 billion yet?
The JWST can fit in Spaceship’s cargo area unfolded. Although I’m partial to the idea of putting a giant telescope in a crater on the dark side of the moon
I too am a big fan of SpaceX but I think it is fair to say things like "If SpaceX Starship" rather than assume it is going to work and work affordably.
Agreed. Also a fan of SpaceX, but I think NASA's approach is 100% reasonable: quietly prepare plans to take advantage of starship (see: LUVOIR) but wait until Starship is proven to do the high level push to switch.
Additionally, you might prefer to leverage the low launch cost to use a different approach than JWST uses. Basically, Big Spitzer.
Instead of a huge sunshade, use a telescope tube and a huge amount of liquid helium (even the relatively small amount in Spitzer lasted many years, and this is one instance where mass directly translates into time). Instead of big unfolding mirror, use a monolithic one.
This would actually be technically superior to Webb (colder mirror and instruments than you can get with the typical Webb cryocooler, less starlight impacting the instruments as your telescope tube with baffles shields it better, less diffraction off the mirror segment interfaces) and ought to be potentially much simpler and cheaper. And you could afford to build more than one, allowing you to reduce risk aversion slightly and increase telescope time.
That's negating the cost of the telescope itself, though. JWST may be more expensive than something you could launch with e.g. Starship, due to the need to fit into an Ariane 5 payload, but it's still an insanely high-precision instrument that would surely have cost $billions even without the unfolding procedure. If you could refuel it for, say, $250 million, because Starship, why not do that instead of launching a new telescope for $5 billion?
I agree with your point but I think that $5 billion is an overestimate for a telescope as capable as JWST which is much less mass/volume constrained. ELT, a ground based telescope vastly more capable than JWST, is expected to cost €1.3 billion.
I don't think ground-based telescopes are really comparable to space-based. Just one of the issues with JWST is the exotic construction required for heat management, which would be an issue for any space telescope even if it was teleported into orbit. This is comparably not an issue with ground-based stuff where you have infinite power, coolant, and heat sinks; e.g. for the ELT: "ESO is aiming to implement proven technologies and commercial off-the-shelf components to build the cryogenic infrastructure for the ELT instruments. A combination of open loop Liquid Nitrogen cooling and low-vibration mechanical cryo-coolers will be installed to provide the required temperature levels and cooling capacities."[0]
I grew up at Lick Observatory in the Bay Area, and really love ground-based stuff, but I'm somewhat familiar with their operations and I guarantee it's got nothing on space 'scopes.
You yourself are making a good argument for why massive reduction in launch costs (like 3 or 4 orders of magnitude compared to Ariane) changes things dramatically. Heat management becomes easier when you can afford liquid cryogens like Spitzer or a larger and cheaper (more ground-like) cryocooler.
You literally could have 1000 tons of liquid nitrogen delivered to your telescope if you needed to, if it saved $1 billion.
I think people still aren’t understanding the ambitions of Starship. We’re not talking about a 30% improvement in cost. But a 300000% improvement in part because you could even afford human technicians…
I'm well aware of the capabilities SpaceX is promising! This is why I said, "even if the telescope was teleported into orbit." If a new ground-based telescope is still $1 bil then something which has to operate in hard vacuum, high radiation, and with even greater temperature differences, with far less provision for repair (even with Starship), will be hard-pressed to come in at an even smaller budget. Then again, $1 bil ain't what it used to be.
On the other hand, you don’t need a massive, expensive structure to keep the mirror from deforming under gravity, everything is already vacuum insulated for you, humidity isn’t a problem, you get 24/7 energy from the Sun using just solar panels (no diesel generators), you don’t have concerns for building on sacred land, you have like 3-4 times the observing time per day (which directly impacts cost per observing hour), independent of weather, access to both hemispheres, and no (or much less) need for expensive adaptive optics and laser systems to partially correct for the atmosphere.
All true! And mostly better for the ultimate purpose of a telescope, which is why we prefer to put them in space. However none of those advantages offset the greater cost, e.g. your "expensive structure to keep the mirror from deforming under gravity" is simply a steel scaffolding. Admittedly to higher precision than an office building, but not extraordinarily so. I think perhaps you are not respecting the challenges of space and the cost to operate reliably in it, even if launch costs were zero and mass unlimited, so I'd encourage you do do a little more research.
Skyglow, atmospheric distortion, atmospheric absorption of specific frequencies, wind, the Earth's inclination, orbit, and rotation (limits time-on-target for any specific target of interest), local conditions (static electricity being a major issue for the ESO in Chile, given elevation and lack of humidity, all electronics must be static-tolerant or resistant), etc., etc.
Not that space isn't also hard, but each environment has both affordances and limitations.
really though, if Starship is that capable, and JWST is still usable, I think you do both. If only to test really crazy things that you haven't been able to look at before because the time was too valuable.
Lower launch costs could enable cheaper R&D for the satellite itself by enabling more testing of components in orbit rather than trying to nail the calculations ahead of time.
Refuelling satellites is currently a hot topic in the aerospace world. No matter how cheap launch gets (and there are some very real limits to how cheap it can get for orbits like what the JWT is in), the hardware itself is quite expensive and it's often worth maintaining older scientific missions for continuity.
Propellant is often a key limitation to life of a satellite, especially for earth-observations sats in low earth orbit (the opposite of the JWT), and it's well worth refuelling a satellite in principle.
The JWT is a _lot_ of expensive hardware. It's not crazy at all to think about refuelling, especially if it's expending significant propellant to say in a stable orbit +/- maneuver for imaging operations.
All that having been said, refuelling is still a long way from reality, and despite a lot of companies marketing refuelling ports and similar things, it will be a long while time until it's a realistic solution. Over the lifetime of the JWT, it probably will become feasible, though.
Refuelling seems to be more like to be done by bolting another engine + propellant, than actually refuelling the in-service engine, based on current concepts.
Some commercial companies (e.g. Orbit Fab) are selling refuelling ports for satellites, FWIW. NASA put a lot of research into it as well, IIRC. For the JWT it's probably quite different, but for commercial earth observation sats, there are lots of folks considering including some of the refuelling port designs in current hardware even though the actually "refuel in space" service isn't available yet.
Cost is important, certainly, but the available space inside of the payload fairing is going to be a huge boon for future telescopes. From what I recall, a tremendous amount of effort went into folding up the JWST just so it would fit in the small space provided by the biggest rocket they could get in 1997.
yeah, the capabilities of JWST was limited by its size which was limited by payload capacity. Also its cost was driven up by lots of things to deal with the size problems, like all of its folding stuff. We could put up something cheaper and better today if we just had the payload capacity.
I suspect the only "controversy" in your comment is that you said something positive about SpaceX.
I believe the GP is correct: wear and tear on existing components means that fuel won't be the only issue in 20 years. Hubble has been serviced 5 times [1] for example.
Part of the complexity (and thus cost) for JWST was all the issues introduced by trying to fit a 6.5m mirror on existing rockets. All those moving parts and points of failure have design costs.
What you may find in 20 years is that we'll want to launch an even larger mirror and/or use interferometry between multiple telescopes to improve effective resolution.
> It's weird, Musk was the golden child on HN about 2 years ago when he was electrifying cars, now a pariah because of his wealth.
I wouldn't say he's a "pariah because of his wealth." If anything, he's probably a pariah for consistently, wildly over-promising (overshooting "optimist" to land in "liar" territory) and being a jerk (e.g. defaming that the cave diver, among other things).
Then add to that obnoxious fanboys who've made him a weird tech Jesus, and who defend him and bring up his brain farts at every opportunity. I, at least, wouldn't mind never hearing about him again. Lets hear about the cool people who actually did the cool stuff (and just happen to work for companies he's invested in) instead.
1. People like to hate on things and people just because they're popular when there's literally no other reason; and
2. A large number of people will let their personal opinion drive their behaviour. Elon is a dick, no question. Because of that some people will just downvote or speak ill of SpaceX or Tesla. Worse, this dislike can be used to rationalize pretty antisocial behaviour (eg doxxing, swatting).
What SpaceX has done is nothing short of astounding whether you like him or not. I'm not sure of the exact number but I believe SpaceX has raised <$20B and brought launch costs from >$50k/kg (Space Shuttle) to $1-2k/kg to LEO. It seems highly likely that Starship will drive that below $1k/kg, possibly by a lot.
By comparison, a single SLS/Artemis launch is likely to cost more than that.
And if you think it's just a question of throwing money at the problem, just look at the abject failure that is Blue Origin (fun fact: Blue Origin was founded 3-4 years before SpaceX).
I don't see him being treated as a pariah on here. He is being judged by the many things he does which as times goes on will vary more and more. Some will attract praise and some will attract scorn.
I would bet big that most people on here have a fairly balanced opinion of him that roughly would look like:
- Almost single handedly accelerated the electrification of cars by a couple of decades
- Together with many amazing engineers, scientists and more, led to huge reductions in launch costs and increased frequency of launches
- He acts carelessly online with respect to the law around securities
- He acts carelessly online when he wants to insult someone
- He doesn't really care much about light pollution that affects astronomers
- Overhypes many of his ideas and doesn't recognise any criticism of his failures
- Has an implausible idea that we can colonise Mars this century
I am both impressed by the man and have a few misgivings. Like any human being he is multifaceted.
Hyperloop BS was a big turning point for me. That flipped my opinion of him from a smart guy with a lot of resources to do what he wanted to a rich idiot that got lucky hiring great people.
I think a certain Thai rescue plan and attacking an individual may have something to do with that. Musk is a great entrepreneur, but not a nice person.
Given the forthcoming availability of larger diameter rocket fairings, I think we'll see a number launched that will make JWST obsolete at the end of 20 years, but who knows!
the large rocket you're talking about has been said to possibly make that particular company bankrupt if they don't manage to ramp up their engine production soon. and the market for heavy launch vehicle is tiny. only 3 FH were flown as far as i know.
also the irony here is that the only the only client this company has now is itself to launch his telecom satellite swarm, which in turn will have a negative effect on ground observations, both in VIS and RF bands. astronomers heavily rely on ground based observations, because on the contrary to space telescope the can modify their instruments easily.
you can do a lot with other technologies, for instance diffractive lenses, chronographs as a separate spaceship, etc, etc... the best for a telescope is not always to have the biggest single piece mirror.
i know i know, i'll get heavily downvoted for the above, i just don't like that the said company test their stuff in a middle of a natural reservation.
> i just don't like that the said company test their stuff in a middle of a natural reservation
I guess you must really hate NASA then.
> Visitors to Kennedy Space Center Visitor Complex are often surprised to discover that they are just as likely to be greeted by an alligator or dolphin. This is because Kennedy Space Center sits in the middle of the Merritt Island National Wildlife Refuge adjacent to Canaveral National Seashore, one of the largest and most diverse wildlife preserves in Florida. In fact, the refuge supports one of the highest numbers of threatened and endangered species anywhere in the nation.
I see a very large amount of launch infrastructure. You don't build that much without disregarding the needs of what lived there first.
Much of it was built before the EPA existed, so routine was routine. But, it is still being expanded, lately on behalf of SpaceX. Scheduling in lots of studies and meetings just amount to delaying, if they can't actually affect whether the paving happens. No amount of public hand-wringing gives a turtle back the nesting site its ancestors have returned to for a million years, or a hundred million.
5% of what? They paved over 100% of what they paved over. That number will not change, however much they pave over.
If the supposed conservation programme doesn't actually block paving, then it is what they call a formality. Business-as-usual is routine.
The US space program was practically moribund for those 50 years. The paving was done quickly at the start. With space activity ramping up, paving will too, as we see starting already. What are you demanding as a definition of "routine" beyond paving where they like, when they like?
The US Space programme was moribund? No Space Shuttle launches then?
You say they are routinely abusing the area and all I'm getting from that is that they've paved over areas, 5% of the area. How is this routinely abusing the area?
Could you post an journal article explaining how this has routinely abused the area and put the ecosystem at risk?
Could you post a journal article identifying what percentage of an already radically reduced habitat of numerous threatened and endangered species can be paved over without driving any of them closer to extinction?
There's not just SpaceX creating large rockets. Neutron, New Glenn etc. I'd hope some of those would be running in 20 years time or even better. FH can have a larger fairing but it's not 9m, not by a long shot. Also we'll see 3 this year, there was supposed to be one a couple of months ago but the payload wasn't ready.
Also, sure you can have more complex methods to get to the stage where it's analogous to a single large mirror, but that's why it took 25 years to make JWST (amongst policical reasons too, but still).
If constellations are so bad to astronomy, why do ESA want one?
Finally, I think you'll find KSC in Florida is slap bang in the middle of a huge nature reserve, as it has been for the past 50+ years
Really? RocketLab are going great guns. There's nothing outlandishly novel with their Neutron design (bar the 007 style fairing). If you've not seen the recent interviews with Peter Beck, I'd highly recommend you to do so.
Their payload masses are a joke, and they are more than a decade behind SpaceX at this point in terms of development and experience. Falcon 1 was retired more than a decade ago, and they are still flying the equivalent today.
I don't think they realistically stand a chance to outcompete SpaceX within the next ten years on any dimension, after all, SpaceX is a fast moving target itself. But that's just my opinion, so we'll have to wait to see how it plays out.
It would be great to have a real competitor to SpaceX, that can't come soon enough, I do give them better chances than Bezos and his toy factory.
For space telescopes (which this topic is about) doesn't need super heavy lift capability, just larger diameter. Neutron is planned to be 7m diameter.
Please, just watch the interview. It might change your opinion by listening to the plan, I know I felt much more optimistic about more serious players in the field.
I agree in principle, I think they are the #5 player right now in the commercial lift arena, SpaceX first, ArianeSpace second, ULA third, the Russians fourth and then Neutron. Which is quite an achievement. There are other players but those are not commercially available. So they are in excellent company but they still have a very long way to go, which given their funding is only to be expected. Once they start to fly heavier payloads and more complex engine configurations they will be a player to be reckoned with.
I'd be interested to see what the Arianne 6 turns out like given A5 is now sold out, but it still won't be reusable so high cost despite half an A5, but that doesn't matter as their main customer is ESA and they're pretty wedded to them politically.
I'm not aware of any reusable vehicles by ULA and all the current flights are fully booked, they're sold out of their current block. There were only a handful of launches last year, I think Electron actually flew more. For the new, they're waiting for engines from Blue Origin but they'll probably end up using RS as it doesn't look like BO will deliver.
The Russians (and Chinese) are basically copying anything SpaceX in terms of reusable heavy lift, which might be a good plan in the long-term but it's not that innovative.
Better a good copy than a bad original. Copying the leader is smart. Innovation is expensive and risky, something the Chinese are not very well equipped to do (yet) and the Russians can't afford.
I think long term if Ariane Space and ULA don't adapt that they'll die unless they keep being subsidized. But if SpaceX manages to reduce cost even further then that will make no sense, it is already very hard to justify.
> has been said to possibly make that particular company bankrupt if they don't manage to ramp up their engine production soon. and the market for heavy launch vehicle is tiny.
I read Musk's statements regarding this towards his workforce as a pure power play to put pressure on them working even harder on ongoing issues like you mentioned.
I don't have any insights into this but that wasn't my point. I simply pointed out my opinion, that the message was so intense, that it was looking to me as a pressure play.
That being said - if you can produce n amount of engines per time frame, I am positive that they manage to achieve n*x amount of engines per the same time frame as well.
> i know i know, i'll get heavily downvoted for the above, i just don't like that the said company test their stuff in a middle of a natural reservation.
Wasn't that a bit of over-inflation from dodgily-backed NIMBYs, especially in a state where petrochemical industries have abused a lot more natural environments?
A telescope that can see back to the beginning of the universe is never obsolete to astronomers. The Hubble is 'obsolete', but there are plenty of astronomers that would step over their own mothers to get time on it.
> but there are plenty of astronomers that would step over their own mothers to get time on it.
May I suggest "there are plenty of astronomers who would cut their left hands to get time on it". Similarly florid, but does not propagate the meme "people will often be evil for the right price" -- that meme is self reinforcing, the more we believe in it, the more true it becomes, and the worst the world becomes as a result
I believe the world becomes even worse when people are unable to speak candidly, frankly, and in their own way. Being able to extract and recognize the meaning behind someone's words, in spite of any perceived flaw in word choice or phrasing, is one of the hallmarks of a mature and intelligent individual.
This belief that controlling how people speak will somehow make the world a better place seems somewhat quixotic.
This is helped a lot by the fact that's it's quite hard [EDIT: = expensive] to place an upgraded telescope somewhere. Hubble is still used despite it's tech being a few decades old.
I'm trying to parse those sentences, are you saying there are space constraints with hubble? it's orbit isn't at a particularly special elevation or inclination, I'm pretty sure we could have several telescopes in the same exact orbit but half an hour behind with no discernible consequences. Even out at the lagrange points, you don't have to be /exactly/ there, many cubic kilometers of space have roughly the same properties that make it appealing for JWST.
It's really expensive to get telescopes up in space. We have a lot of astronomers that could use some time on a space telescope, but launching enough to supply all of them is not economically viable in any way. Sure, the stuff hubble is currently used for is not as groundbreaking as when it was launch, but we still have use for it.
My point it is, we have so few space telescopes that even having time on an "outdated" one is still pretty valuable.
EDIT: Maybe a better example, it's not much use for a first-world person to use a ten year old smartphone, since current smartphones are much more capable and they're comparatively cheap. Planes, on the other hand, are used for decades, since simply buying a new one is very expensive. This is despite it's tech being far superior.
Putting a device into space is relatively cheap for a project like this, and is only dropping with each year. Say $100M - $200M, on a $10B project, puts the launch at just 1-2% of the price tag. I believe the Hubble total project cost is pushing past $16B in adjusted dollars.
It's the massive capital expenditure on the telescope and its infrastructure that is the significant limiting factor on the pace of putting newer and better telescopes in place.
Apparently for the cost of all the Shuttle trips to Hubble, they could have just put up another Hubble without its problems.
Same thing in this case: instead of visiting Webb, they could build a new Webb without all the origami, and assemble it by hand in orbit for a tiny fraction of the cost, and end up with two of them. Then, maybe put different instruments on the second one.
it can only be obsolete if there's a replacement deployed. given the cost, it is unlikely to have one as long as the one that is working keeps working.
best case you have two working mid-IR telescopes in space instead of one. i don't hear any astronomers complaining about that scenario!
I generally agree with your assessment that there are other moving mechanical assemblies that are likely to fail at some point as well so the practicality of re-fueling may not be optimal.
But I also just wanted to point out as people discuss re-fueling that some of the concepts for this are not just open up the fuel tank and add more fuel but it might be operationally simpler to make a satellite that attaches like a jetpack [0]
reaction wheels are a new kind which does not suffer from failures like the Kepler - this is a very recent development.
electronics on the voyager still work, 45 years after launch.
it is possible that things will break. it is also possible that they won't. we'll see in 20 years, but having an option on the table in case they do work is simply prudent engineering.
the reaction wheels have failed on a number previous missions, it appears to be down to solar storms inducing current in the spacecraft and arcing across the bearings causing pitting, and so increased friction.
I don't think they can know for sure, however the bearings have been designed with this in mind using ceramics. Also I just realised with the JSWT going around the L2 point it won't be cutting through the Earth's magnetic field, mind you it will be exposed to the direct solar wind.
Question for astronomers: Based on the linked article from that blog post about the five LaGrange points relative to the Earth and Sun (https://webb.nasa.gov/content/about/orbit.html) are there similar points associated with the other planets? If so, how does the heavier gravity of the Sun (for a planet like Mercury) or the gas giants and their large moons impact the points?
Yes, Lagrange points exist for any two bodies in orbit so long as:
- The ratio of masses between the two bodies is sufficiently large.
- The mass of objects orbiting at or near the Lagrange points is sufficiently small.
There are Lagrange points in the Earth-Sun system (JWST will orbit near L2), the Earth-Moon system (the "L4 Society" is named for one of these, proposed as the location for permanent habitable space colonies), and the other planets of the solar system and the Sun.
For bodies of sufficiently similar masses, the Lagrange points aren't well defined, as with Pluto and its comparatively giant moon / sister-dwarf-planet Charon.
And there are limits to the mass of an object which can be orbited at a Lagrange point. It's not possible, for example for there to be a "twin Earth" orbiting opposite the Sun from Earth, at the L3 point, as the mass of that object would destabilise the entire Earth-Sun-Twin system.
Lower mass of the secondary system would move Lagrange points closer to that body, higher masses would place Lagrange points at a greater distance from the secondary (lower-mass) body in an orbital pair.
I'm not sure what the situation is for highly complex orbital systems as with Jupiter and Saturn in which there are many moons which might peturb orbits near other planet-moon Lagrange points, though I suspect that these would still be reasonably well-defined for some of the larger moons of Jupiter and Saturn.
I am curious about Mercury's Lagrange points. Per the video, they should theoretically exist ... but have astronomers observed natural satellites at those locations, like the corresponding points for Earth or the Jupiter trojans?
I doubt an anti-Earth maintained at L3 would de-stabilize anything at L1 or L2, but L3 is anyway unstable, so such a planet would soon get far enough from L3 to become a problem for L4 or L5, not to mention for itself and Earth.
The lagrange points exist regardless of the masses of the bodies. However the perturbing forces acting to pull bodies away from those points may be stronger or weaker depending on the masses involved. For Jupiter for example there are several thousands of asteroids that sit at it's L4 and L5 points and make up a group of asteroids called the Trojans[1]. So it's points are especially stable because of it's large mass. The Earth-Moon Lagrange points for example aren't very strong.
JWST will not produce products, only data. In the 10-20 years it will operate, it will ingest enough data for tens of thousands of scientists over hundreds of years to analyze.
Seems like an aggressive estimate. For example the Kepler spacecraft produced a lot of data for its planet finding mission. The light curves that it sent back had some automated processing, but had multiple rounds of inspection for identifying the "objects of interest" and then confirming actual planet candidates. The backlog was on the order of a year to when data was taken. This had the additional complexity that to confirm a planet transit you really had to see it pass in front of the star twice to confirm the orbital period.
JWST will also be delivering similar data over its lifetime, but I would assume that ground processing of that data will significantly improve over that timeframe.
A kindergartener today will utilize Kepler data 15 years from now in a novel way we are technologically locked out of today. Technology will always breath new life into a dataset.
The data don't get stale, so scientists will be able to make inferences based on that data for as long as they'd like. A lot of it will never stop being useful.
If a much better telescope comes along or an especially dynamic phenomenon is discovered there might be a temptation to take more pictures of something that has already been captured, but otherwise, why would you? This data is expensive and will probably remain so for quite some time, for the obvious reasons.
Would a hypothetical refuelling mission risk contaminating the mirror/sensor with manoeuvring propellant, assuming it would need to adjust its position very finely in the close vicinity of the JWST?
I have a related question. Would it be feasible to launch a future JWST-style mission into a simple heliocentric orbit, which doesn't require any stationkeeping at all? It will then drift away from Earth over the years, eventually being as distant as L3, before getting closer again. And I appreciate it can be harder to communicate to something that distant. Yet, communications tech has come a long way in the last few years, arguably even farther than stuff like ion thrusters, and I wonder if it wouldn't make more sense to put effort into providing sufficient bandwidth at 2 AU rather than better stationkeeping. Especially if the mission isn't meant to be serviced anyway.
The main constraint for JWST is that it needs to be able to block all IR radiation from the Sun/Earth/Moon in order to pick out the faint IR signal it's looking for (from red-shifted light from the very early universe). By orbiting L2, it keeps Sun/Earth/Moon all on one side of the spacecraft, which it's then able to block with its sunshield.
I assume it could still be operated for a few months out of the year when it runs out of fuel, assuming the thermal cycles don't trash the ability to align and calibrate everything.
Insufficient fuel means not remaining on station. There's probably an end-of-life contingency to push the telescope "over the top" as EOL is approached, such that it transitions to an independent heliocentric orbit rather than endangering other L2 missions or returning (eventually) to Earth along an uncontrolled trajectory.
Is the fuel supply only designed to keep it in orbit? What happens when it runs out of fuel and leaves L2? Can it continue to do science while "on the float"?
for a short while - for as long as reaction wheels can keep it pointing away of the sun and the high gain antenna can point towards Earth (it doesn't have 360 degrees rotation freedom). i don't know the details, but it'd probably amount to a few months at most.
The issue is fuel though. NASA has talked about the possibility of using a small robot to refuel it, but said that they don't have current plans to do so. Servicing it (making repairs, upgrading, changing things) would probably be too expensive but refueling is definitely worth considering.
I get that part. The interesting part is if building a new instrument will be marginally more useful than resupplying the current one. A few years back there was a demonstration of an orbital vehicle for refueling satellites. So, which is better: spending a few more billions for capturing a few more frequencies of infrared light or spending a few hundred millions for extending the life of the current mission.
Any background / literature you're aware of on this?
At what point do uncertainty effects (limits to measurement precision) and risk (danger of rolling "over the top" of the L2 point, and requiring reverse thrust, which JWST cannot deliver) come in to play?
I'm guessing they gave themselves some wiggle room :) . They did not miscalculate fuel. They did the classic "overestimate by 2-4x" and you'll come out smelling clean either way with the bosses.
I don't understand why the Telescope requires fuel at all, except to change its orbit position. Couldn't it just rotate counterweights via electric motors, powered by solar cells?
The first reason is that it needs to reach its destination... IIRC the JWST needed to accelerate itself to avoid damage on its initial orbital insertion (rather than relying on the launch vehicle). It also needs to stop once it reaches its destination. Electric propulsion doesn't provide enough thrust for this particular mission. Electric is better suited for very slow acceleration buildups rather than quick corrections.
It does actually have reaction wheels to control attitude without propellant, but it needs fuel to unload the momentum. It's possible the JWST could get into a situation where electricity wouldn't unload the momentum fast enough.
But its orbit isn't perfect or perfectly stable: Other forces than just the Sun-Earth system act on it, albeit very weakly. Some include photonic pressure (photons from the sun pushing on one side, not the other), the moon, a few scattered particles (space isn't perfectly empty), etc. And the fact that the JWST itself isn't a point mass means that it is tugged at by gravity slightly differently in different places. Then add to all of these the most important fact that L2 is an unstable equilibrium (a local potential maximum, like a hill), and the telescope is more like a dancer on its toes needing to right itself by throwing something every now and then.
All these things necessitate expending some fuel for station keeping.
Yes it does exactly this. It uses reaction wheels (circular counterweights) for rotation generally, but when they can no longer spin faster it will have to use propellant to adjust its angular momentum back to zero.
In addition, it uses propellant for orbit position keeping (station keeping) as you wrote.
AIUI (I'm no expert, someone will no doubt correct me if I'm wrong), the L2 Lagrange point is not stable. If you were perfectly at the L2 point the forces would be balanced and you'd stay there, but you'd have to perfectly at that point with zero perturbations, which is impossible.
It's like standing a sharp pencil on its tip - the slightest disturbance causes an accelerating fall, so it always falls. In the case of L2 any object placed there will always drift away with accelerating velocity.
To counteract this you need thrust, and that needs reaction mass. You can't do it with gyros etc, you have to chuck something out in the opposite direction to the way you want to push.
Edit: Incidentally (again not an expert) this sounds like maybe a useful quality of L2. L4 and L5 are stable which I assume means they're filled up with space garbage and odd socks, which maybe would be a problem for putting things there?
It needs propulsion to get into orbit. On its current trajectory, without some delta-v, it would zip right by L2. Once in orbit, it needs propulsion to stay there.
It also needs propulsion for attitude control. It does have reaction wheels, but once those are saturated you have to spin them back down. The only way to do that without transferring all that momentum back to the rest of the spacecraft is to use propulsion to counteract it.
Does anyone else have an inexplicable subconscious desire for the JWST to fail catastrophically? I've been a huge fan of the project for years, but after launch my mind was constantly plagued with these urges. I can't seem to explain or get rid of it. "Call of the void", maybe?
Anyone else with this problem? I'd really like to stop thinking these horrible thoughts.
Intrusive thoughts. They're far more common than society lets on. Just try not to act on it. But if you do try to destroy the JWST, please document the process as NASA might be interested.
I legitimately thought it for several years as I wanted it to act as a restorative force in the US space industry against mismanagement. It 'deserved' to fail to 'punish' those responsible for it's mismanagement. That was my thinking for quite a few years. However now I think SpaceX is doing a better job of leading that charge by simply pushing the industry forward towards being a little less risk adverse and avoiding analysis paralysis. Carrot is always better than the stick, when it works.
Not totally fail, but somehow I would’ve liked to see a bit of drama, so that some clever engineering would have needed to salvage the mission. And this is probably what most of the engineers were expecting and had contingency plans already drafted for many of the mechanisms.
I've had my occasional "wouldn't it be funny..." moments, but oddly enough, for the telescope I can confidently say "no".
Even from purely an entertainment standpoint, the prospect of getting new images from deep space in unprecedented quality and resolution seems a lot more interesting to me than some drama and blame-shifting about billions of NASA dollars going up in smoke.
If you want the experience of a 20 year project dissolving into nothing, you can just rewatch the news coverage about Afghanistan from last summer.
But yeah, it would certainly fit into the string of bizarrely bad news of the last years. Maybe it feels so weird that some project actually appears to succeed for a change?
I think it's because our boring safe lifes makes us want a little bit of thrill.
It's the same feeling when you want society to colapse because 'how cool would be to be a survivor in an apocaliptical wasteland'. Or when you vote for a bad candite saying "f..k it, let's see what happens"
I experienced this with the collapse of the twin towers on 9/11. I was horrified by the human cost, but so, so interested in what I was seeing. I had often wondered what the collapse of a super-tall would be like, and there it was, on TV.
In terms of life-extension vs. replacement of JWST, it's helpful to think through what opportunities might exist.
There are a set of telescope plans which are presently in consideration, including WIRST, the wide-angle infrared telescope; HabEx, the Habitable Exoplanet Imaging Mission; Lynx, a next-generation X-ray telescope; and the Origins Space Telescope, an infra-red telescope even larger than Webb.
This links as well to a good YouTube video describing each of the proposals.
For telescopes, among factors I'm aware of are:
- The total number of devices. More 'scopes means more points of the sky which can be imaged at any one time. This permits detecting either rare or transient events. There are also possibilities afforded by multiple devices operating in concert, providing both greater positioning sensitivity (angular resolution) and increased surface area, though more the former than the latter.
- Wavelength specificity. Infra-red, radio, visible light, UV, and X-Ray sensitivity all permit detection of different phenomena. Devices suited to one wavelength may not be suitable for others. Specific research goals may favour specific observational methods.
- Other sensing modes. Spectroscopy (which provides information on chemistry of remote objects).
Gravity, gamma ray, and particle sensors (e.g., neutrino sensors, cosmic-ray detectors) may afford other options. There are proposals for space-based gravity-wave detectors, for example.
- Compound devices. The HabEx system in particular has two components, the telescope itself, and a sunshield used to block the light of an observed star, which would operate at a separation of 100s of thousands of km.
- Collector size. Larger mirrors permit gathering of more light. This permits shorter collection periods for brighter events, and imaging of previously undetectable phenomena. The Hubble Deep Field views are an example of the latter, and pushed the boundaries of known and and observable phenomena tremendously.
- Storage, processing, and communications capabilities. I don't know how much this contributes to observation capabilities, though I suspect it has an impact.
- Developments in phsyics, materials, and sensing, generally. Looking through lists of physics and chemistry Nobel awards since the 1970s, a surprisingly large number have concerned capabilities rather than fundamental characteristics or properties of matter or the universe. Many of these afford new capabilities in sensing and detection.
- Probes. Rather than a single instrument which views distant objects, probes get close to a specific object, or set of objects, and make close or direct observations of these. Various landers, impactors, flyby, orbiter, and similar missions, to date all to objects within the Solar System, would be examples of these. These compete with other missions (manned, long-distance sensing).
- Earth observation. Probably the largest class and most productive set of space-based observation platforms has been looking at our own planet.
It's also worth thinking through what has made JWST possible, including launch platforms, experience with complex deployments, manufacturing, sensing, and control capabilities. These will have impacts on future missions, and further development might also extend their capabilities.
In situ fabrication or assmbly might offer the greatest opportunity The possibilities of constructing telescopes either in low-Earth orbit and transporting them to an observation orbit, or on remote bodies (the Moon, perhaps an asteroid) also exist. I'm thinking through scenarios in which larger launch craft (Starship, SLS), space-based assembly, and possibly even temporary construction structures --- effectively an inflated balloon in which engineers and technicians could work in shirtsleeve or close-to-it conditions --- might be used to assemble very large structures without relying on the complex deployment ballet used by JWST, or being constrained to the dimensional constraints of the Ariane V launch vehicle and fairing. An asteroid, de-spun, could provide both a shield against solar and Earth-based radiation and emissions, and structure and materials for at least some assembly. This presumes that the asteroid's own orbit would be sufficient for observations and that instruments would be sufficiently aimable from that point.
Finally: most technological improvement tends to follow a sigmoidal curve: an early period of slow development, a period of rapid attainment, then a slower period of approaching theoretical maximum efficacy. New developments or combinations of technologies may restart that curve, but often 15 years doesn't deliver transformational development. Rather older technologies are refined, reliability improved, costs reduced, or flexibility increased. I suspect we'll see a mix of these factors --- some diminishing returns as existing modalities and mechanisms are perfected, and some new avenues as novel combinations do become possible.
Well, if it's 2040, I might figure it's within the realm of possibility that multiple vendors can somewhat predictably service it in whatever orbit it still has. QED the Webb launch itself, I think people working on this stuff are starting to grow a proven track record. 20 more years of practice might yield a simple process to 'top off the gas tank'.
"It's around 20 years of propellant, roughly speaking,” though he added that it’s a preliminary estimate.
There are likely many factors that influence propellant usage which are unknowable - for example, photon pressure from the sun, which can vary over time in an unpredictable way.
I didn't realize the JWT will need to burn fuel in its steady state. Its pretty disappointing that this took 20 years to build and we will only get 20 years of use out of it.
Then you're going to be disappointed by all satellites I'm afraid. They all need to do station-keeping, and have a way to maintain orientation when they spin-down their reaction wheels. "Solar-powered" thrusters use fuel too but use an electric field to accelerate it.
20 years is still a rather long time. Expect something else fragile to fail before then. And that's still double the target life time! (And unless they've made it almost maliciously difficult to add fuel, I'm sure there will be some Space Bro who'll offer to refuel it for likes / tax reasons.)
> Then you're going to be disappointed by all satellites I'm afraid.
Except we launch well over 1000 satellites a year. The JWT is clearly a bigger deal than that. This has been advertised as NASA's magnum opus. The fact that it was only supposed to last 10 years makes it feel much less significant...
And those satellites, by bulk, are in low earth orbit with a lifetime of usually 4 years, and a legally mandated reentry in 25 years.
JWTs location in L2 (a mathematically unstable location that requires energy to not roll back into a gravity well in any direction) is like putting it on the satellite equivalent of K2 and not coming down from the peak for 20 years and you compare it to the thousands of commuters that made it up the hill down the road from your house.
A few, but he one that is the closest rubber that hits the road is part of the FCC filing for radio spectrum access on satellite projects. Without which, you're not getting on most rockets.
Swarm breached the "Mitigation of Orbital Debris Second Report and Order" which has been in place since 2004[0], for their launch on an Indian rocket because their 0.5Us would breach this and their aerodynamics wouldn't comply because the satellites were so small and didn't have enough atmospheric drag to bring them down in time. The tracked by radar aspect was resolvable by Leo Labs radars, but not the atmospheric drag component.
There is no legal requirement of that sort that I'm aware of. However, it is recommended that LEO satellites should re-enter the atmosphere within 25 years of mission completion. This is to try and mitigate the ever-growing issue of space junk in LEO.
.. and 99% of those probably spend 100% of their time trying to sit utterly still in their orbit, staring down at Earth, maybe twitching around to point a bit if they're doing spy work.
JWST pivots the entire spacecraft to point the 6 meter mirror. I'm sure they've optimized the consumables on the schedule, but it simply 'costs resources' to do this sort of work. I assure you there are gruellingly dense and optimized observations plans afoot.
Compare to e.g. the very successful Herschel Space Observatory -- it too went out to L2(-ish), did everything it was meant to do in its three year mission, and managed to extend to four before (drum roll) running out of fuel, this time for cooling. JSWT solves this cooling issue by some incredibly funky mechanical resonance cooling. Herschel "only" cost about $1 billion, and it will be interesting to compare the science results.
Also don't forget it at no point can it turn around and face the earth or sun or the light coming from the suns direction will burn out the optics. If it does it once, and it's mission over. All the while essentially driving most of the way up out of the gravity well and letting it get pulled back to earth a little and repeating. If it goes too far over the peak of the hill it will go over the other side with no way to reverse even if the rocket has the fuel.
I think you are misinterpreting where the fuel consumption comes from. It isn't the reoriantation. That you can do with internal reaction wheels. All you want is rotation, not movement. Turn something inside in one direction and the outside will turn the other way.
The only problem is movement for that you need to eject stuff the opposite way you want to go. And that is needed because L2 is unstable. I.e. you roll down over time. Which needs to be counteracted by station keeping. I'm pretty sure they'll use the fuel usage to measure the local gravitational field around L2 and from that update mass distribution estimates around the inner solar system.
Station keeping, yes, is probably going to need the lion's share, but I have no idea by what factor. I have read that dealing with reaction wheel saturation is also another fuel consumer though. Perfect reaction wheels attached to a spherical cow would use no fuel. As would perfectly balanced solar pressure engineering etc. It basically all ends up nibbling some fuel.
10 years of operation, but hundreds of years of data to analyze. We are still analyzing data captured from terrestrial telescopes that haven't operated in decades.
No idea, but if it's difficult for acedemia to get hold of this then how could startups? More to the point, what would be the value add to make the commercials viable? Interested to hear if you think there could be?
Perhaps there's some altrusitic archive.org style site that needs to exist for science, that features datasets of multiple PB in magnitude and allows anyone to pull the full archive.
Maybe in the future, but still, people still have access to source imagery and they regularly make spectacular images and material from public domain data from space agencies and interest groups. You don't need 4PB unless doing something like, well, imaging a black hole.
It's fun, not sure how much there is run a business from it, unless you plan on taking the data and creating spectrographs for some future mining mission way in the future? :D
I mean, is there something you'd suggest they should have done differently? I'd imagine they gave it as much fuel as they possibly could while meeting all of the other design goals. Is is possible you're more disappointed with the advertising than the observatory itself?
My real concern was the difficulty we had getting the JWT ready. If JWT's successor will also take 20 years to produce, then we better start working on it tomorrow. A 10-20 year lifespan on the telescope would be perfectly fine if we could launch a new one every 5-10 years.
I'm worried that NASA has spent all its money and political will (and then some) getting JWT over the finish line.
Maybe a big infrared space telescope isn't the highest priority to build next compared to other instruments we could put in orbit.
I mean, we'll still have some big terrestrial infrared 'scopes. And we'll be coming off 20 years of very good space infrared scope data... And we'll have had the smaller Nancy Grace Roman Space Telescope up in L2 also (launching in 2027, nominal life 5 years).... ESA is launching an exoplanet-focused infrared scope to L2 in a similar timespan... Presumably other "smaller" infrared scopes will fly by 2042. So...
There's so many wavelengths and different possible space telescope missions. Let's not replace JWST (assuming it gets a normal mission life)-- let's keep some infrared capability and do something else.
Yes, infrared scopes on earth have challenges and are not equally viable for all wavelengths. But VISTA, UKIRT, IRTF, etc, cover a substantial amount of the near and intermediate infrared-- the latter two are high enough to reach into a reasonable amount of the far infrared.
Most of JWST's wavelength coverage is energies that terrestrial telescopes can do (just less well). It's not like Herschel which went into the far, far infrared (and had its life limited by liquid He as a result).
Re: Moon-- Why put a telescope down a gravity well?
Most of the discussion of telescopes on the moon I've heard has been about radio telescopes, where a huge hunk of rock between you and Earth can be a feature.
Roman is slated for launch in 2027 (and survived the JWST overruns!), LISA in the 2030s, and there are a few competing proposals that haven't totally firmed up for the next decade too: LUVOIR, HabEx, and a few others
There are at least four major proposals in the works, including another two IR telescopes, one with an even larger reflector, another with a wide-angle field of view; an x-ray observatory; and an optical + starshield pair (operating at 100k+ km separation) planet-finder. I've just posted in another top-level comment (https://news.ycombinator.com/item?id=29894335)
Further optical and gravitational observatories are amongst further options.
I'd be surprised if other NASA programs weren't nearly as long. Maybe not that long, but heck, I've heard to design a new car at a major car company normally takes 6 years or so, I would imagine a brand new type of one-off space project may take at least 10.
The Mars Opportunity rover was planned to last only 92 days but lasted about 5200 (~14 years). I think many NASA programs have short expected timelines and then hopefully outlast them.
10 years was not quite worst case but definitely a conservative estimate.
L2 is an unstable orbit and needs constant corrections to not drift away, so JWST has much more significant fuel needs than if it were in say Hubble's orbit. How much fuel it would have left for these maneuvers depended on how precise the launch was (i.e. how much fuel it needed to spend on corrective burns just to get to L2). This was obviously uncertain until after the launch, but ten years was a lower bound above which the launch would not be considered a major issue--if it only had say 5 years of fuel left after the launch that would be an indication that the launch was flubbed some how.
TLDR: JWST was not "supposed" to last only 10 years. It was designed and built to last much longer, that was just a lower bound assuming nothing went very wrong.
cf. Mars rovers operating long past the "planned" mission length, e.g. Opportunity's "planned" 90-day mission turning into over 5,000 days. It is vastly unfair to the people who designed and built Opportunity to say it was "supposed" to last only 90 days. It was built to last much longer; 90 days was a lower bound for the mission to be considered a success.
The scale and intensity of the problem is much bigger though.
This one is hundreds to thousands of times further out than any of those satellites, for instance. It also has a far longer lifetime compared to the average, even before this news. Four times the distance of the moon from Earth. There's no luxury of being able to repair, service and refuel such a thing without approaching or exceeding the costs of just making a new, better one with the learnings and savings from before.
(edit - the "earth moon" distance isn't to scale with respect to planetary diameters... the distance from the earth to the moon is about the same as the sum of all the diameters of all the planets - that's a long way itself)
From the Wikipedia page of the Large Hadron Collider
"After some years of running, any particle physics experiment typically begins to suffer from diminishing returns: as the key results reachable by the device begin to be completed, later years of operation discover proportionately less than earlier years"
> Perhaps the same applies to space telescopes too?
Not really. The amount of targets that can be explored with JWST would take far longer than 20 years to image. And many targets, such as exoplanets or expanding novas, benefit from periodic reimaging with the same instrument.
Those targets themselves represent varying levels of interest and returns. The distribution of these is all but certainly a power law or Zipf function itself.
That's not to say we'll run out of interesting things to look at. Only that there is in fact a case of diminishing returns and interest.
We probably will have even cooler stuff up there in twenty years. Also, with the accessibility of space opening up, a refueling mission may become possible.
Most likely not refueling, but docking with a spacecraft that will provide propulsion. Has been tried with MEV-1 spacecraft docking Intelsat 901 a couple years back. JWST has a docking ring for that purpose.
If I were a 100-billionaire, I’d finance several of these. There was a fashion among the very rich 100+ years ago to finance ground-based telescopes and have it named after themselves
Weird nobody mentioned yet, JWST is at L2 (permanently shielded from sun by earth). L2 is not a stable and need correction burns to stay there that's the reason for life time of 20 years.
Only stable - self correcting - are L4 and L5 points .
JWST isn’t in Earth’s shadow - it orbits around L2 (approximately perpendicular to the Sun-Earth axis) at a radius comparable to the Earth-Moon distance. JWST has a huge solar array used to power the electronics on-board.
Even if it was stationary at L2, Earth wouldn’t completely shield it from the Sun - the point is too far from Earth/the Sun so large for it to.
Think about what the craft is doing. It isn't just sitting out staring at one location. It orbits the Sun but doesn't want to ever see the sun. I bet if we wanted to get extra clever we could do flip maneuvers to preserve fuel, but if JWST hasn't met its goals in 20 years then messing about with time wasting tricks won't help it.
Nothing is impossible, but L2 is much further away than humans have ever been. AFAIK, we do not have any human rated spacecraft even remotely capable of going that far (and, hopefully, coming back).
Current plans are for it not to be serviced. Considering that it’s sitting way beyond the moon at L2, it’d have been out of each even for the shuttles when they were still in service.
However, hopefully it’s not out of reach of the hardware we’ll have in 20 years. Even though right now our capability is actually less than 20 years ago…
JWST will be so far away from earth that is unlikely any human will ever get near him. Also, Hubble was designed to be serviceable during its lifetime. This isn't the case for JWST.
Maybe technology will develop enough to allow us to send drones to work on JWST, but today this is still just a dream.
PS: I'm just a random code monkey on the internet, so take these comments with a grain of salt.
20 years is a long time, and space is moving fast these days. I wouldn't bet on it not being serviced (although I do agree that we'll have something better by then).
If I were to bet on something it would be a simpler but bigger design that takes advantage of Starship’s much wider fairing.
Let’s say we wanted a constellation of telescopes to do full sky surveys of small objects in our system for asteroid detection. Do those need to be kept at near absolute zero to be effective at that task?
Webb has a specific mission of imaging deeply redshifted space. I would hope in 20 years we’ll be able to launch bigger, simpler, and cheaper designs for more “pedestrian” missions.
It's unlikely anything at L2 could be serviced until we have significant infrastructure in space (like something for refuelling). Hubble orbits about 400 miles up, JWST is about 1 million miles away.
JWST was designed for future refueling capabilities (there is a docking target and an externally accessible port for access to propellant storage), and this mission is well within existing launch vehicle capabilities (if a robotic refueler is lifted as payload). At launch, JWST was fueled with ~301 kg of propellant, so subtract that from launch vehicle payload to get an idea how heavy your refueling vehicle can be (assuming roughly 4k-5k kg depending on launch vehicle), and some margin for the refueler to separate and propel itself over the gravity edge JWST balances itself on from L2 into deep space post refueling.
> Webb faces other operational challenges, however. Hubble has been kept alive in part through maintenance and servicing runs done by astronauts. Webb’s great distance from Earth makes that kind of house call impossible. What’s more, in order to remain stable at its gravity-balanced Lagrange point, Webb needs a thruster system, and a thruster system requires fuel. The telescope will launch with a full tank, but that will be only enough to keep it operating for a minimum of five years and a maximum of 10. In theory, a refill ought to be possible, and the telescope is actually equipped with a docking target to accommodate an incoming spacecraft that could conduct a refueling and extend the JWST’s life. It’s an appealing idea, especially considering the telescope’s dizzying price tag. That spacecraft, however, does not yet exist, though it could within the next decade.
To be honest, sounds like a cool project to start working on, with the idea that it becomes an off the shelf capability for future space observatories. SpaceX's Dragon can carry a 6000 kg payload, and already supports autonomous docking with the ISS, for example.
By "servicing" I actually meant more "repair". The initial burns left enough fuel that JWST is likely to wear out before it runs out of fuel. The refuelling I meant was for craft to get people there and back, because repair is significantly more difficult than refuelling.
My mistake. In that case, it'd likely be more reasonable to get a vehicle to the observatory, boost it back to Earth orbit, and then attempt to return it to L2 after on orbit servicing. I don't know what that Delta-v budget looks like, although I'm happy to throw coffee money someone's way if they want to do the math in this thread.
Think about the state of technology 25 years ago. Are you disappointed that things built back then are obsolete now? Why should satellites be any different?
Rather than lament its lifespan, I am hopeful that a couple decades from now we will build and launch something that is exponentially better.
Sorry this is a one off unique device. 20 years is a great life in the history of NASA, plus they will most likely have robots that can refuel it in 20 years easily if it's even worth doing with 20 years of advancement in astronomy by then.
We have that guideline because putting down your peers like this is reliably the marker of a bad comment, and leads to significantly poorer threads. We all love to feel superior to others, or (probably the same thing) to ward off feeling inferior, but this is a low-grade mechanism and never a source of interesting conversation. It also pretty much dominates the internet and we're trying for something different from those defaults here.
HN comments have been overwhelmingly positive about the JWT and it is currently one of the most popular topics that appears here.
This was, and continues to be, a momentous accomplishment.
The fact that it happened at all is a herculean task in constraints management, not only on the engineering side, but also on the political and zeitgeist-management side (e.g., managing different adminstrations with often antithetical perspectives on the value of science, etc).
A lot of folks on HN only see this from their own perspective, of "how-can-I-disrupt-X", or "I would have done it so much better", without a real appreciation of the overwhelming complexities in pulling off a task with so many moving parts (literally and figuratively).
Sure, you could have done it better. Then do it. But don't diminish the value of a truly monumental accomplishment when it happens; they don't come often enough, and more often than not, projects with this level of ambition fail far before they ever get to the point they can be critiqued by arm-chair geniuses.
it's something that was never done before and one of the few things that will create all kind of new sciences.
Your comment is really frustrating. few people in this life can do something that was never done before, much much fewer on this scale, much much much fewer with such impact on science and humanity.
I find it interesting that planning overruns such as this seem to get pinned on implementation, rather than the planning and approval processes themselves.
The evidence is that the time and cost it took to produce JWST are what they are. That planners lowballed these estimates, or that administrators and legislators wouldn't have approved greenlighting based on accurate estimates, speak to failures in planning and administration, rather than engineering.
Much of the planning / large-project literature, which I've studied for some three decades, seems itself to be largely blind to this distinction.
As to many comments found on the Internet mirroring such viewpoints.
I don't want to tell NASA/ESA/CSA how to operate, but I haven't heard of a single software product that launched 10 years late. Such a product would be immediately DOA because of how fast technology moves. Obviously a space telescope is literally rocket science, so it's nothing like the next popular JavaScript library, but I think NASA could adopt a little bit of the move-fast-break-things mentality. Apparently they're running Python 1.5 on the JWST ffs.
All I'm saying is there's room to improve. JWST would be a monumental success for humanity even if it launched 20 years late.
I'm curious as to why and whether some of the delay had to do with the public and lawmakers getting impatient and trying to cut it short, then actually forcing it longer, then blaming the engineers.
Yeah, the limited lifespan would be much less concerning if we had any reason to believe we could iterate and crank out more / better telescopes in the future.
I guess I just assume they learned a lot in building this and that knowledge will transfer into new telescopes, launches, deployments, etc. Do you think they didn't learn enough by figuring this out?
I am not confident that whatever caused JWT to take so long will be solved for the next project. NASA by its nature does not really benefit from "scale". Every important thing they do / produce is novel.
I am sure they have learned alot from building JWT, as they certainly learned a lot from building Hubble or the space shuttle. I don't think that knowledge necessarily transfers forwards to make the next project easier.
Well, as you seem to have said, NASA doesn't seem too interested in scaling but rather in doing things that stretch the bounds. If their goal isn't to scale the previous project but to push past what people thought were possible with experiments, that seems OK to me.
Ah I hadn't know. That being said, perhaps one thing they learned from this is which materials they may not want to use again in the future. I dunno, I just struggle to imagine that they didn't learn a lot from this and that most of us have really any idea whether the learnings are worth $10B, $1B, $100B, etc.
1. For an astronomer, you can already build such a system yourself quite trivially by getting an large mirror, mounting it in space with a really big catapult, and then using origami to unfold everything. From earth, this telescope could be accessed through everyday ham radios.
2. It doesn't actually replace the Hubble. Most people I know still want to see things in the visible spectrum, and IR fake images just don't cut it. This does not solve the visible spectrum issue.
3. It does not seem very "viral" or income-generating. I know this is premature at this point, but without charging users for the service, is it reasonable to expect to make money off of this?
Haha! Glad you enjoyed it. I thought I was too over the top with the large catapult as a launch system and HAM radio for telephony, but I guess people oversimplify/handwave worse details
Well, considering the progress in space in reaching the moon and the arguably stagnant (except recent developments like reusable boosters) developments since then, I think it's very reasonable to be disappointed in the past years of space development.
> arguably stagnant (except recent developments like reusable boosters) developments since then
What about Voyager, ISS, Hubble, Mars rovers, Mars helicopter(!), and Cassini/Huygens missions? There's more to do in space than just going to the moon. I'd love to see us back there as well, but I think there's still a whole lot to be excited about.
agreed, all incredible stuff, I replied to another comment with a fuller reply, but despite these incredible recent achievements I think the years since apollo have been overshadowed by failures in rocket development and innovation (except spacex) and nasa under funding. I linked a story about SLS delays and funding levels and Nasa budget in my other reply
Human spaceflight has stagnated for sure. However, we have multiple rovers on Mars. We have satellites that tell us exactly where we are on Earth. We took pictures of Pluto. We exited the solar system. We landed on an asteroid. We slammed into a comet. I choose to be excited.
All undeniably incredible achievements. I look at Nasa's budget [1] and see the government achieve something incredible in the apollo project and take their foot off the gas on the most exciting (and potentially unifying) frontier. I also look at the corruption and stagnation in US rocket systems like SLS and the sinkhole of hours and dollars it has been [2].
I am very excited about space and the future, I just think that in the years since Apollo the story has been emblematic of wastefulness, contractor level benign corruption (cost plus contracting) more than it has been inspiring with the stories you mentioned. just my opinion.
Seems like the real and hard truth is that, at anything resembling our current tech levels, human spaceflight just doesn't add much value compared to the massive, overwhelming difficulty.
We've sent hundreds of robots all over the place. To Mars, Jupiter, asteroids, comets, the outer planets, out of the Solar System entirely, as close to the Sun as can be managed, and everywhere else in between. For basically all of these missions, sending humans along would be 1000x more expensive, and the humans would be bored to tears for 99.9% of the time. For most of the rest of the time, they'd be relying on the same instruments as the robotic missions, as the environment is too harsh for anything else. So what's the point?
And who would we be sending? We could send super-smart scientific experts to maybe follow up on things a little faster, but it'd be a waste to have them sit around for years on the voyage back and forth. Or we could send more ordinary folks, who might not be all that much more capable than the robots we're sending now.
Sorry, it might burst some peoples bubbles of romance and sexy space adventures, but it mostly just doesn't make sense to send humans into space for the type of exploration missions we're doing. Maybe if we can send enough resources to actually have a colony on Mars or something, but we're not there yet.
> NASA's budget peaked in 1964–66 when it consumed roughly 4% of all federal spending....In 1973, NASA submitted congressional testimony reporting the total cost of Project Apollo as $25.4 billion (about $156 billion in 2019 dollars).
I wonder if there also wasn't that level of waste at that point but not too many people cared because the country was mostly terrified by the USSR and wanted to win.
Ironically, I think the more we think there's corruption and waste, the more that may lead to corruption and waste, as we distrust and defund and discourage. Again, I imagine some of the waste comes from the fickle attitude that some of the public and lawmakers have towards funding these orgs.
NASA was wasteful and full of contractor corruption during Apollo as well. They just had the political will to get funded and keep pushing forward so they did.
The stagnation in aerospace is mostly due to us running into fundamental limits of physics pretty quickly, not due to some kind of work ethic or creative failures. to keep pushing forward in space would have required another order of magnitude in funding, and funding during Apollo was already huge. That said, I wouldn't mind if all the worlds military $$$ had been dumped into mars colonization either.
I only get opportunities every few years to affect in a minuscule way NASA's budget and mission, the rest of the time I have to act as a passive observer. In that time I choose to be happy with what they've accomplished and excited for what comes next.
It has to be cost-plus or no one would do something that has not been done before. Fixed cost is fine for something you have a grasp on production costs.
I'm not a space scientist but it look sto me that human space travel is insanely hard and, if there's no infrastructure at the destination humans won't be able to do much... So, maybe it's too early to wish space travels ? Maybe it'd be safer to first colonize with robots, install infrastructure, make sure the travels are safe enough by sending animals or other life forms and then once ready, send humans ?
It's a perspective thing. We have incredible technology but at a loss of what to do with it. We had the cold war pushing us to achieve great things in competition but now we are stagnant. Our tools are too powerful and dangerous to wave around, we don't know how to balance investor and worker class wealth allocation, we can't seem to control anything about society that used to just fall in line.
As to what we can do in space: the value of reusable boosters is very understated. Why don't we have a manned mission to Mars? Because it takes a huge payload with lots of delta-V. Sending ten rockets up for orbital refueling was always a pipe dream in terms of cost. Suddenly it's attainable and the solar system is our oyster. It's still expensive, but we now have the tools.
Look - super impressive but it's not hard to find downsides. This thing took 20 years and near a billion dollars; at some point you should be asking, "Why couldn't we have had it sooner or cheaper or some combination of the two?"
Say it wildly over performs reliability.. it lasts not 20 years but 1,000 years - is that more of success? I'd argue against that - it's more of a failure because we don't need it to last that long.
What if - hypothetically - we had JWST 10 years ago for half the cost but it were just winking out right now? Would that be a failure? I think that's at least an arguable point.
20 years of taking pictures, but we'll be able to study the data it gathered, and benefit from discoveries it enabled, for an indefinite amount of time.
Can we change this link to include the hash, or find another one? The top headline I saw was "Chicago schools reopen this week. But the fight reflects a nationwide struggle" and I was really confused. (The <title> of my tab bar also reflects that headline even if I use the link with the hash, annoyingly). I had to scroll past nine other articles to find the James Webb Space Telescope one.
Is it? That's the URL for morning-edition-2022-01-11 which is also what their share buttons injecting into the share popups. Are they pruning those often?
It's definitely a great example of an engineering/science project run by grownups. Compared to what I see in the daily cloud software engineering world...
It's completely correct to say that modern software development has evolved into clown cars and that big infrastructure projects are run to far higher standards.
It was a grandiose, information-free putdown. Those are flamebait. It also included name-calling ("grownups") which obviously multiplies the flamebait.
The issue isn't how correct you are or aren't. The issue is comment quality. Your comment was low-quality regardless of how correct you are, or feel.
I cannot stand this kind of comment. It's worse than nerd sniping. Rude for no reason, not curious, not intellectually stimulating. Reddit level drivel.
Perhaps a better question would be - for public or enterprise facing projects of similar budget, why is the perceived $X/$Y/$Z so much lower? That is a discussion worth having, and can help unpack your bias and assumptions into a worthwhile conversation.
As other people have replied, differing missions and costs of failure explain most of this, although in my opinion CADT in web development is actually the primary problem. I won't link the jwz's essay here for good reason.
In short, the expansion of the web economy has allowed for incredibly lazy programming, being done by minimally qualified people, mostly motivated by short term gains, who consistently forget the expensive lessons of previous generations. The original web technologies were fairly good- HTTP and HTML both addressed a need, and I think they were sound (never liked html's derivation from sgml, though, and I don't agree with HTTP's decision to be stateless) but so much of what's sprung up since has evolved with no real natural selection.
It's because the constraints are so different. Deploying to prod is incredibly expensive in this case and you practically cannot iterate outside prod either.
I see this every day in the difference between SaaS and on-prem Enterprise software. If you have a bug in on-prem, Enterprise every customer needs to deploy the patch. You need to update all affected, supported versions, etc. In SaaS, you just deploy and more often than not that's it. This changes the way you do everything and it comes with a high cost. JWST is the most extreme example on this spectrum.
I helped run a world-class MySQL installation for one of the world's largest tech firms. The install was the most mission critical system at the entire company and downtime was extremely expensive.
I was hired because during failovers, the engineers were often getting unhandled runtime exceptions in the failover python code. (much of it was untested except when running failover) Often, the engineers would break one thing while cleaning up another thing. All of this was OK, because the system failed infrequently enough and was eventually replaced with spanner.
This is an interesting example as the domain is probably closer (albeit still far away) to the JWST than a photo sharing app is. There is a very high minimum bar to get anything into production because of high regulatory requirements. I bet iterating in this area is much slower and harder because of regulatory hurdles. Definitely an area that requires different processes than your typical SaaS web startup.
I wanted to say that for 10 billion USD I could also deliver you miracles in the "cloud software engineering world", but the truth is probably not.
If a pure software project would get that kind of money people probably would feature bloat to infinity. The JWST during its design phase were under very strict limiting factors. Volume limit, mass limit, power limit, etc. Compared that with any software project where obviously there are limits but they are much more malleable. You can argue that we need to provision 20% more servers to achieve our goal, but you cannot argue that we need to stretch the Ariane 5 by 20%. (Well you can argue, but the rocket is not going to get stretched.)
So all in all, it seems I'm agreeing with you. But I don't think it's about the quality or grownupness of the participants, but more about the shape of the problem.
The way I think about it is the standard was set by the Apollo engineers. I think many of us are familiar with the MCP and all the other cool details about the hardware of the mission, but the reality is: everybody who worked on that had previously done something similar, but for the military, and they took every bit of hard-won experience from the previous projects (ballistic missles guidance, military radar, data coding, etc) and applied it in a totally unceremonious and highly effective way.
I think the modern computing world instead is not grownup, but rather CADT (cascade attention deficit teenagers). A constant developing of new solutions that copy previous ones, but are typically worse, or have the same problems as the previous ones. This seems endemic in the industry, albiet with exceptions.
There are plenty of subsets of the software industry that are grown-up.
Anybody who wants to learn more should read the RISKS mailing list and its archives. It's remarkably hard to produce reliable software but a number of groups around the world can do it.
Examples I can think of: the teams that built the series of ESS for AT&T. The folks who built Erlang (telecom reliability is a common theme here, being one of the other technical areas where software and hardware engineering excellence greatly exceeds that which we see from typical groups today). Even Qt, although the quality of their code and its adherence to the principles that make Qt great is variable, I'd say is a good example of a system built by grown-ups.
BTW, when i say "grown-up", I don't really mean anything directly related to age, although age and experience are the best proxies for grown-up. Grown up is really a way of saying: working with more weight on wisdom as raw intelligence (Ghemawat's law), respecting experience even if it's not obvious why you should, (Chesterton's Fence), using statistical testing techniques effectively for quality control (Shewhart), practicing discipline to ensure long-term compatibility and not burning your dependents (jwz's law of CADT). I don't think there's a general term for acting with these principles, I just mentally associate them with being a grownup who has learned from experience.
> Anybody who wants to learn more should read the RISKS mailing list and its archives.
Yes, totally second that, that's the best school there is, seeing what goes wrong and what the consequences are. I probably spent weeks just reading and analyzing the various posts there.
As for the part of the industry that isn't grown up: anything that can do OTA or automatic updates is likely to suffer from a rash of bugs and usability issues, which includes everything that's SAAS and almost all application software with the exception of some industrial stuff. There is far more low quality software than there is high quality software.
If spinning up a new microservice would be as complicated and expensive, as yeeting fragile scientific equipment to a Lagrange point, you'd see better engineering in the cloud software world.
Lots of talk about refueling even with the 20 year lifespan, from what I've gathered having watched a lot of the NASA conferences and livestreams this past year, with this amount of operational fuel capacity the problem in 20 years will be on operational lifetime of wear components, not just the fuel.
The reaction wheels are _large_ moving parts on the JWST. The cryocooler for the MIRI is a very finely calibrated moving part. It's a closed system, but still relies on pumps and electronics. After 2 decades of operation it's very likely that these will be experiencing some issues.
While in 2 decades it might be feasible to refuel the JWST, it seems very unlikely it'd be worth it given the operational wear of every other component. Had we used too much fuel to correct the course to get where we are the math may have been very different. Seems to me that we're fortunate that we can instead dedicate resources to the next-gen observatories!