Hacker News new | past | comments | ask | show | jobs | submit login

I wonder if people in general are fit for the G-forces they're subjected to when launching into space.

I think astronauts usually go through very rigorous testing and training. And I'm not sure that is something we can engineer ourselves out of.




Per https://spaceexplored.com/2021/05/06/can-you-make-it-as-a-bl...:

> When it comes to the G-Forces being pushed on you, many roller coasters have peak G’s at or above these limits. Most people are probably familiar with the different rides at Walt Disney World so let’s use those for examples. At EPCOT, Mission Space is a centrifuge-based ride where you go through a simulated launch and landing on Mars. The sustained G’s on that ride is 2.5 G’s, close to how many G’s New Shepard will experience during launch.

> For the descent, Blue Origin says you must be able to withstand 5.5 G’s, if you ever rode Rock ‘n Roller Coaster at Disney’s Hollywood Studios, you would have experienced up to 5 G’s during the initial launch of the ride.

Epcot Mission Space (the "Orange" version) is pretty intense as it's really sustained G-forces, but manageable. During the ride, you have to reach in front of you to press some buttons, and that's when you feel the G-forces most. But for SpaceX/BlueOrigin, passengers do nothing.

Rock n Roller Coaster itself for the peak G is done by kids, not a big deal.


This is slightly misleading - what matters isn't the peak G force experienced, but moreso the integral of force over time. In a roller coaster you might experience 5Gs, but only for a moment. Astronauts experience 3G, but for up to 5 minutes continuously


On the Gravitron, a centrifuge carnival ride in the shape of a flying saucer, riders experience 3Gs for minutes. Best carnival ride as a kid, we rode it continuously for ages.


Oh god, I will never forget that ride. I was at a carnival when I was around 13 or 14 and rode that ride, and midway through it had a malfunction. They stopped it to address the issue, and then decided to give us an extra long ride to compensate for the problem. When it was finally over and I was about ready to stagger off of it, the operator got on the mic and said, “who wants more?!?” Seemingly everyone but me screamed for more. At that point I was too sick to make any sounds at all.

That night, hours later, as I lay on the floor of my friend’s bedroom (it was a sleepover), trying to fall asleep, I still remember feeling like the room was spinning. I never went back on that ride.


Funny, something really similar happened to me! 14 years old, at a friend's birthday party at Magic Mountain. The Superman ride was new. That's where you get into a bullet shaped gondola and get shot up a vertical tower, with a giant statue of Superman at its apex, go briefly weightless and then freefall backwards until you curve flat and brake to a stop. Never big on roller coasters, I got peer pressured into this one.

I didn't like it all that much. But what scared the hell out of me was when, on descent, the brakes malfunctioned. This caused the gondola to go screaming backwards past the platform where the next riders were lined up, fly through some butcher curtains and go crashing into a padded wall in a hidden cinder block cell at the end of the track.

We all sat there for a minute pretty stunned, and then some goofy employee came running out and jumped up on the front of the car. "Whoops! That wasn't supposed to happen!" He said. "But I have some great news for you! Who wants to go again??"

And of course, all the kids cheered.


I thought they shut it down for a while after an incident like you describe.


I remember it had a little window in the door and if I accidentally looked at it, I would realize I was spinning and Instant Nausea.


My brother and me tried this ~4 years ago (we are adults, but still, carnival is fun). I handled it well, but my brother was traumatized. I think you ought to check each future passenger if the sensation of being compressed and having troubles breathing won't trigger a phobia.


Oh man. I hit my head while riding one of those as a teenager. Ruined my whole night at the fair. Never again.


Reminds me of this classic scene (retching sound suppressed for the faint of heart): https://www.youtube.com/watch?v=WdWWqV0jUVc


> we rode it continuously for ages.

Until it stops

People who apparently don't have motion sickness are funny, I know proactively not to go on things like that


The area under the curve doesn't matter if the peak isn't big enough.

A physically fit person can probably live normally at 2g all day with no problems other than feeling tired af until you get used to it and all farts being dangerous.

At 9Gs seconds matter no matter how fit you are.


Hang on. Explain the farts bit!


Guessing they meant "sharts".


Spent way too long trying to work out what a dangerous shart might do.


I know it's not exactly the same as living in a 2g environment, but many people seem to live surprisingly long lives with a body weight that is several times what it should be.


Blood in veins still only experiences 1g in this case. At 9 it really wants to be… elsewhere.


If you prop yourself upside-down against a wall before farting, you should be safe.


On a large enough time scale the survival rate for everyone is zero.


Might as well join the military and get your citizenship.


and you experience a huge number of Gs if you fall and bang your head; Concussion occurs at 90-100G!


I rode Epcot Mission Space Orange, and I didn't realize it was a centrifuge. I thought it just cleverly tipped you on your back to simulate G-forces. It certainly felt real, so it's neat to know that it was.


That ride is a puke machine. I was talking to one of the workers and they said their main job is cleaning up puke all day.

I loved it.


You can absolutely use engineering to limit the g forces. It's just a matter throttling back the engines near the end of a stage and/or staging sooner. For example, Gemini peeked at 6.4g, Apollo peeked at 4g and the Space Shuttle peeked at 3g.

3g is low enough that most humans shouldn't black out, even without training.

I'll also point out that professional astronauts are expected to remain functional for the entire assent (including emergencies, where g forces might peek much higher), which is not required for passengers.


“Gemini peeked at 6.4g”

I remember reading that the Titan 2 pushed so hard that even the astronauts, who were pretty tough test pilots back then, were happy when the engine finally shut off.


Astronauts also need to be able to survive 1) high g reentrues (apollo reached 7 gs on reentry) and abort modes, which can be very high acceleration indeed


Yes, though you can engineer reentry too.

For example, the space shuttle uses it's wings (and body) to generate quite a bit of lift and spread the reentry over a much longer period. the g-forces during re-entry. It's 10min at 1.7g.

Though that's from LEO. Apollo came in directly from the moon at a much higher velocity, resulting in ~7g; For the Apollo missions that never left earth orbit, reentry was more like 3.5g.

A space ship aiming to carry untrained passengers will pick designs and mission profiles that are within their passengers abilities to withstand for both launch and reentry. Apollo picked a design and mission profiles with 7g reentry acceleration because they knew their trained astronauts could withstand it.

As for abort.. it's only limited spikes of high-g you only need it to be survivable for the passengers, while the pilots need to be able to control it.


Starship does kinda do a shuttle wing entry right?


Yeah, it has some lift. Not as much as the space shuttle, but more than apollo.

I couldn't find published numbers for reentry.

I know it hits 2.5g for a second during the final flip maneuver, I suspect they have engineered it to hit about the same during reentry.


Cool stuff!


IIRC the peak for Mercury-Redstone was alightly higher than Gemini at about 7g.


Most are. If you have certain heart conditions, you might not know you have them, and then die. That's why it's likely that they'd require an ECG (and maybe have an age limit and require generally reasonable health/fitness), but if you're a reasonably healthy adult, it should be fine.

Forces depend a lot of the specific vehicle. The space shuttle peaks at 3 G, I've seen numbers from 3.6 to 4.5 (again peak) for Crew Dragon on the way up, 3-5 on the way back. Soyuz seems to be 4 on a good day and 10 on a bad one, plus the momentary forces during landing.

Since we put anyone willing to pay a few bucks on carnival rides that sustain (!) up to 3 G for minutes, and the profile can likely be adjusted at the expense of reduced payload capacity, I don't expect this to be a big problem.


If William Shatner can do it in his 80s, I'm pretty sure that a substantial fraction of the population can do it.

Don't get me wrong, Shatner has worked hard to keep himself in shape. And he didn't get to orbit. But if you keep in shape (and are rich or famous) it may be an option.


The dude was 90 when he went to space, 92 now. He won the genetic lottery it seems - in amazing shape/looks for his age.


Shatter didn’t go into orbit though. But generally I agree.


Will Shatner was 90 when he was on a suborbital launch with Blue Origin. Given his wealth and access to quality healthcare etc. he was probably a decent amount healthier than the median 90 year old, but given that he was able to do it without issue I imagine the vast majority of humans under the age of ~60 or so can definitely manage.


They sent two very ordinary people with only months of training on the Inspiration 4 mission.




Consider applying for YC's Spring batch! Applications are open till Feb 11.

Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact

Search: