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JPL Open-Source Rover Project Based on the Rovers on Mars

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Re: JPL Open-Source Rover Project Based on the Rovers on Mars

#51

Post by rurban »

nikofeyn wrote: post #41
marsRoverDev wrote: post #33

Earlier quoted context omitted.

The hardware we use for non-earth stuff is effectively arduino-level (ok, maybe not exactly - but on the order of 70-100Mhz) because of the constraints put upon it by the radiation hardened hardware. Writing python is a trade-off between computer resources and developer time; we've got a lot of developer time and not a lot of hardware resource, so we write in compiled languages. There are also some safety implication…

has JPL ever investigsted alternative real-time systems? say a real-time ML (as in sml, f#, etc.)?

Rover management was against anything modern or dynamic. They only trusted proven technology. Even if it was hardened C.

Re: JPL Open-Source Rover Project Based on the Rovers on Mars

#52

Post by macintux »

rurban wrote: post #50
craftyguy wrote: post #7

It's interesting that the rover code itself is written in python. That makes it more approachable..

You can be 100% sure that no python code is on Mars. Not even Common Lisp which is much more secure and performant is on Mars. The real rover code is all hardcore C. Erann Gat gave a presentation on the Lisp Conference about the JPL rover code and simulation.

I'm a bit disappointed they're not using Forth.

Re: JPL Open-Source Rover Project Based on the Rovers on Mars

#53

Post by willangley »

tomp wrote: post #22

if anyone has worked at JPL or similar, what's the best resource for learning how to make an actual Mars/Moon rover? I'm very curious about things like, what kind of wheels you need for regolith, how to manage extreme temperatures (electronics, motors, batteries, cameras), how communication works (could you have a remotely-operated lunar rover?), dealing with radiation (SpaceX works with consumer electronics AFAIK, b…

> could you have a remotely-operated lunar rover?

Yes. The Soviet Lunokhod program built and flew two successfully in the early 1970s. I don't know the details of how they did this, but it would make sense to use more automation today. A 2.6 second ping time is long enough that pilots who have played modern video games are likely to complain :).

Re: JPL Open-Source Rover Project Based on the Rovers on Mars

#54

Post by tomp »

willangley wrote: post #53
tomp wrote: post #22

if anyone has worked at JPL or similar, what's the best resource for learning how to make an actual Mars/Moon rover? I'm very curious about things like, what kind of wheels you need for regolith, how to manage extreme temperatures (electronics, motors, batteries, cameras), how communication works (could you have a remotely-operated lunar rover?), dealing with radiation (SpaceX works with consumer electronics AFAIK, b…

> could you have a remotely-operated lunar rover? Yes. The Soviet Lunokhod program built and flew two successfully in the early 1970s. I don't know the details of how they did this, but it would make sense to use more automation today. A 2.6 second ping time is long enough that pilots who have played modern video games are likely to complain :).

I don't think ping is the problem... the problem is "line-of-sight"... Obviously, Earth rotates too fast, so you'd need to use a network of Earth-satellites getting the signal from the moon and transmitting it to the ground station. The other problem, maybe, is how to communicate... Can you have an antenna/laser on the rover itself, or would it need to transmit to a Moon-satellite first (e.g. to save weight on the lander)? How much energy do you need to communicate, can you do it continuously or do you need to "save" energy for a quick burst of radio signals every so often? Is there any other kind of interference (Moon regolith allegedly flies up to 100km above the surface)...

These are just simple issues that came to my mind. No idea how relevant they are, and if there are more relevant issues.

Re: JPL Open-Source Rover Project Based on the Rovers on Mars

#55

Post by makmanalp »

iwakura wrote: post #45

This is great. But it's a little discouraging to see the project only use the US Customary units considering this is a science project. I was under the impression that NASA used SI.

It's more common than you'd think - I remember sitting in a talk in college by someone from Scaled Composites (they did SpaceShipOne etc) and they had said that they use inches everywhere.

Re: JPL Open-Source Rover Project Based on the Rovers on Mars

#56

Post by _verandaguy »

squarefoot wrote: post #49
iwakura wrote: post #45

This is great. But it's a little discouraging to see the project only use the US Customary units considering this is a science project. I was under the impression that NASA used SI.

I think it's aimed at students, schools etc. Its purpose should be to attract people to science so it has to be less intimidating, hence the choices of the Raspberry PI or the phone app or the Xbox gamepad to control it.

It's a weird world where kids are more scared of the metric system than they are of a credit card-sized Linux computer with its guts showing.

Re: JPL Open-Source Rover Project Based on the Rovers on Mars

#57

Post by Cshelton »

iwakura wrote: post #45

This is great. But it's a little discouraging to see the project only use the US Customary units considering this is a science project. I was under the impression that NASA used SI.

Wasn't the conversion, or lack thereof, the problem with one of the Mars rovers some years back? The one that landed on the surface, rolled off the pad and died. I'm sure someone here knows more details about it, but I remember it being something about the teams not converting correctly/at all between the two systems...

Re: JPL Open-Source Rover Project Based on the Rovers on Mars

#58

Post by Cshelton »

rurban wrote: post #50
craftyguy wrote: post #7

It's interesting that the rover code itself is written in python. That makes it more approachable..

You can be 100% sure that no python code is on Mars. Not even Common Lisp which is much more secure and performant is on Mars. The real rover code is all hardcore C. Erann Gat gave a presentation on the Lisp Conference about the JPL rover code and simulation.

Have they used/possibly still use Ada?

Re: JPL Open-Source Rover Project Based on the Rovers on Mars

#60

Post by elkos »

If you are interested in other open-source space technologies feel free to check out Libre Space Foundation's (https://libre.space) code repositories (https://gitlab.com/librespacefoundation/)

We aren't NASA or JPL but a non-profit based in Greece. We already run SatNOGS (a network of satellite ground-stations), UPSat (the 1st satellite with components mainly under the CERN Open Hardware License) and on the side we work on amateur high power rocketry telemetry and PocketQubes.

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