Is it possible for someone other than NASA to send a message to the rover? I'd be happy throwing a little money at a project to ping it monthly to see if there is a response.
Yes and unlikely :-) The protocols are all documented but the ability to receive signals from the rover requires a pretty sensitive receiver and antenna combination. If you have the resources to build a 10m or 15m steerable radio antenna parabolic dish then you could probably manage it.
That can't be that expensive unless you want it to be storm proofed. But it wouldn't be super cheap either, the receiver is probably going to be a bigger problem.
Would be a good starting point. But keeping it stable under wind load is going to be the major challenge. That would be one heck of a project, it would likely take a few years of your time to pull it off.
This quora answer (https://www.quora.com/What-bands-signals-and-protocols-are-u...) claims that even the 70m DSN antennas have a hard time hearing the rover to earth transmissions. That is 10x the diameter so 1000x the surface area of a 4.8m dish like the one the guy built.
That said, there are no doubt interesting hacks you can do to help this but steerability is always going to be a concern to maximize the SNR of the very weak signal coming from the rover.
Yes, the precision required would be insane. That is also what makes this an interesting project, even if you fail you will still learn a ton about all kinds of engineering principles. Expensive lesson though!
Another big factor would likely be how far Mars is away from Earth, at the close extreme it will probably be substantially easier to pull this off.
What an interesting article by the way, thank you for that link.
You could send a message. The source code is available[1], but you would need to build or have access to a large antenna, which would be extremely difficult and/or expensive.
It's physically possible but I'd have to imagine there's a security key required for the Rover to accept a message and there's no way in hell NASA would give you that key.
I get the argument for why nuclear weapons aren't physically locked -- there's always people guarding them -- but not having security on a remotely operated billion-dollar device seems crazy to me, even if the technical barriers to establishing a link are high.
The person answering doesn't really comment on deep space missions, but I think the conclusion you draw (no encrypted link) is almost certainly right for Spirit and Opportunity, which were launched in 2003.
The thinking used to be that a 70m radio dish (and all the accompanying deep knowledge about pointing, relative velocity, channel codes, etc.) would be enough of an obstacle.
This thinking has definitively changed in the meantime.
