The fact that this level of work is given away for free with the intent of making the world a better place makes my heart dance.
I am so optimistic for the future of humanity.
JPL Open-Source Rover Project Based on the Rovers on Mars
31–40 of 73 posts
Re: JPL Open-Source Rover Project Based on the Rovers on Mars
#32Python? God riddance!
The real rover code was in C, and the simulator in lisp.
Re: JPL Open-Source Rover Project Based on the Rovers on Mars
#33Looks more like a toy rover project, rather than "an open source rover project". Hoped they will make open source substantial (even if simplified) part of the rover project, so space startups can reuse and improve it.
Why couldn't this be re-used to some degree for a rover in non-Earth with tougher, more resilient hardware?
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 implications centered around determinism etc which mean interpreted languages are a bit more gray area; with a well understood compiler and language you understand what the code is doing better, and you know it will run the same every time. That may be the case with python if you understand the whole shebang, but not that many people do... And if you have that level of knowledge of python, you may as well be writing C or C++.
Re: JPL Open-Source Rover Project Based on the Rovers on Mars
#34This seems really awesome, but my God is it expensive. Maybe I am not reading correctly but it seems like just the nuts and bolts from McMaster cost $230 and that's still excluding the electronics and additional hardware! I guess I'll have to save up a bit before I can play with my own minituare rover. edit: the motors also are going to cost around $500
you think $2500 for a bot is a lot?
https://www.robomaster.com/ , Chinese national robot competition with almost 200 teams competing each year, runs ~$10K bot teams, and those are build mainly from off the shelf DJI components.
Re: JPL Open-Source Rover Project Based on the Rovers on Mars
#35if 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…
Haven't worked in this field, but here are some episodes discussing the topic:
https://www.youtube.com/watch?v=nJLOZDPTp3I
https://www.youtube.com/watch?v=ADJwChUtdDQ
https://theamphour.com/334-an-interview-with-gerry-roston/
https://theamphour.com/220-an-interview-with-shaun-meehan-do...
https://theamphour.com/401-an-interview-with-brent-and-bryce...
https://www.youtube.com/watch?v=FzRP1qdwPKw
I think what you are talking about is mostly just normal engineering in the sense that the process is similar. What really makes space unique isn't space as such but that there is no real-world (real-space?) testing, no inspections after the fact or do-overs.
Re: JPL Open-Source Rover Project Based on the Rovers on Mars
#36Earlier quoted context omitted.
Regarding the motors, they wouldn't be suitable for this particular project but you can buy broken hoverboards really cheaply. Where I live you can get stripped ones (no battery, no logic board, but you can get hoverboard logic boards on AliExpress for under 20€) for 10€ and returned ones (99% of the time it's a dead battery) for 35€. The motors are fantastic and powerful (~350W each), and you can build lots of stuff…
> The only thing that's hard to come by cheaply is the battery. Dead laptop and power tool battery packs usually have at least some useable 18650 cells in them. A friend has built more than one battery pack for electric scooter out of harvested cells. You do have to know what you're doing when working with unprotected cells though.
Yes it's easy enough to get unprotected cells, but the hoverboard batteries usually have short circuit and undervoltage protection, both of which are very nice to have as a beginner. If you know what you are doing you can also get RC hobby batteries for not too much money.
Re: JPL Open-Source Rover Project Based on the Rovers on Mars
#37Earlier quoted context omitted.
Why couldn't this be re-used to some degree for a rover in non-Earth with tougher, more resilient hardware?
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…
Do you find C/C++ acceptable from a safety/reliability perspective, or do you write in safer languages (Fortran, Ada)?
AFAIK critical software coding standards forbid dynamic memory allocation, so things like stack overflows, null dereference or out-of-memory errors can't happen, but array-out-of-bounds exceptions can still get you. On the other hand, static verification tools catch most of that.
Re: JPL Open-Source Rover Project Based on the Rovers on Mars
#38if 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…
I don't work there but I do work at a place that supplies JPL with some of the tools they use to solve the problems you are interested in.
https://www.mathworks.com/company/newsletters/articles/bring...
If you parse the user community and external repos you will find specific code & models for some of those use cases
https://github.com/search?q=matlab+rover https://www.mathworks.com/matlabcentral/?s_tid=gn_mlc
Do note that JPL also uses other tool chains, some open, with similar communities and repos. I'm not as knowledgeable to what extent they use these, ymmv (pun intended)
https://github.com/search?q=python+mars+rover
the fundamental point I would try to convey is that you can learn as they do - through trial and error via simulation.
Re: JPL Open-Source Rover Project Based on the Rovers on Mars
#39if 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…
Haven't worked in this field, but here are some episodes discussing the topic: https://www.youtube.com/watch?v=nJLOZDPTp3I https://www.youtube.com/watch?v=ADJwChUtdDQ https://theamphour.com/334-an-interview-with-gerry-roston/ https://theamphour.com/220-an-interview-with-shaun-meehan-do... https://theamphour.com/401-an-interview-with-brent-and-bryce... https://www.youtube.com/watch?v=FzRP1qdwPKw I think what you are t…
> What really makes space unique isn't space as such but that there is no real-world (real-space?) testing, no inspections after the fact or do-overs.
This is becoming less true today as engineering problems become more complex and simulation tools become more capable. Most automotive manufacturers have virtual models of their vehicles in testing long before the first nut meets it's bolt.
Re: JPL Open-Source Rover Project Based on the Rovers on Mars
#40if 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…
Haven't worked in this field, but here are some episodes discussing the topic: https://www.youtube.com/watch?v=nJLOZDPTp3I https://www.youtube.com/watch?v=ADJwChUtdDQ https://theamphour.com/334-an-interview-with-gerry-roston/ https://theamphour.com/220-an-interview-with-shaun-meehan-do... https://theamphour.com/401-an-interview-with-brent-and-bryce... https://www.youtube.com/watch?v=FzRP1qdwPKw I think what you are t…
>I think what you are talking about is mostly just normal engineering in the sense that the process is similar. What really makes space unique isn't space as such but that there is no real-world (real-space?) testing, no inspections after the fact or do-overs.
This is sort of true?
Spacecraft of all types are subject to a battery of physical tests before launch. This includes vacuum testing, thermal cycling and vibration (where many parts fail). There are normally duplicate components produced for different purposes. Some are just for testing the fit, others are to check that thermal expansion isn't a problem and so on. The actual flight hardware itself is usually tested as well, since it's designed to be repeatedly stressed within certain physical limits.
NASA has duplicate rovers in the lab that commands are tested on. Before a mission plan is uploaded, it's tested on the ground system to make sure that, for example, an inspection arm doesn't collide with the body of the rover. Modern rovers like curiosity are reasonably good at self-inspection, since it can take a 360 selfie. The rover is covered with calibration points, for example to measure how much dust is covering things and how far the wheels have worn down.
A lot of "testing" is gained through experience. Satellite manufacturers know what designs work based on prior designs. NASA learns a lot every time they put a new rover on Mars. Rover missions (like Curiosity, Spirit/Opportunity, etc) tend to outperform their original specs because the engineering is so conservative.
In very rare cases astronauts have done in-space inspections - for example the repairs to Hubble. The ISS is also used as a space-based testing laboratory for hundreds of different projects.
(I've worked in a space science laboratory where satellites were routinely tested, and indirectly on rover data).