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One of the things I find really cool about Ingenuity is how it is in large based on consumer hardware. The main processor is a Snapdragon 801 running Linux whic
by birktj 6y ago
One of the things I find really cool about Ingenuity is how it is in large based on consumer hardware. The main processor is a Snapdragon 801 running Linux which communicates with Perseverance using the Zigbee protocol [1]. Perseverance on the other hand uses a RAD750 from 2001! If successful I hope this can lead to more modern hardware for these kinds of missions in general.
[1] https://en.wikipedia.org/wiki/Ingenuity_(helicopter) https://en.wikipedia.org/wiki/Ingenuity_(helicopter)
- mushufasa 6y agoOne of the fascinating things about space silicon is that NASA spends many years hardening specific processors to withstand the types of shocks and electromagnetic interference from space travel. These intensive processes mean that the equipment they can use is always 10-20 years behind the modern equivalents.
- marcinzm 6y agoAren't smaller transistor sizes also more susceptible to radiation issues which means you can't really use newer processors without ever more effort in radiation hardening?
- Robotbeat 6y agoSmaller transistors also have a smaller cross-section so for the same number of transistors this somewhat cancels out.
- emkoemko 6y agoand yet they are fine with using a snapdragon arm processor on the helicopter?
- syoc 6y ago> Ingenuity runs Linux (for the first time on Mars) and uses the open-source F' software framework on a 2.26 GHz quad-core Snapdragon 801 processor. Radiation hardened processors aren’t fast enough for the real-time vision requirements of the experiment—but as an unprotected COTS processor, it will fail periodically due to radiation-induced bit flips, possibly as much as every few minutes. NASA’s solution is to use a radiation-tolerant FPGA ProASIC3 to keep an eye on the CPU (paper) and software that attempts to double-check operations as much as possible. “[I]f any difference is detected they simply reboot. Ingenuity will start to fall out of the sky, but it can go through a full reboot and come back online in a few hundred milliseconds to continue flying.” Source: https://orbitalindex.com/archive/2021-02-24-Issue-105/#ingenuity https://orbitalindex.com/archive/2021-02-24-Issue-105/#ingen...
- KMag 6y agoI would be interested in seeing what they did to get Linux booting and their userspace daemon running in ~300ms or less. Depending on their non-volatile storage read rate, using an uncompressed kernel might not actually save boot time. I'm guessing they aren't running traditional init or systemd. I've been told LinuxBIOS is able to get you a text console login prompt faster than hdd platters can spin up, but it takes Ubuntu tens of seconds on my SSD laptop to get me a login prompt. I'm surprised they don't have an FPGA MEMS autopilot with a simple degree 2 or 3 polynomial model of the flight dynamics , with the CPU and Linux only being involved in making adjustments to the autopilot. Or, maybe that's what they're doing, and by "falling out of the sky" what they really mean is the autopilot drifting.
- mhh__ 6y agoThe helicopter is both only rated for a certain mission and potentially liable to smash straight into the ground. On top of that, I'm sure JPL would love to move with the times, which is why the helicopter is using the more modern processor.
- fuzzy2 6y agoThe CPU will probably be destroyed by radiation before long. I'd guess the key factors here were weight, power draw, size and perhaps performance. A radiation-hardened CPU probably didn't fit the bill. It's also super expensive.
- lnsru 6y agoAny individual part is peanuts compared to overall mission cost. Anyway, it’s a great PR stunt for QCOM. It’s not that big secret, that cubesats successfully use automotive grade off shelf parts.
- lights0123 6y ago> perhaps performance absolutely performance. Yes to the other three for sure, but the engineers reported that there was no way they were running flight control using image tracking on a 200MHz CPU.
- tal8d 6y agoNot in python, maybe. Smartbombs have been doing the necessary image processing with much less processing power, on much less capable sensors, for a long time.
- NikolaeVarius 6y agoWhat. I dont understand how you can make this claim. Guided bombs are NOT using CV with optical cameras. They use lasers, GPS, and other non "fancy" techniques. I just don't get in what world you think military munitions are using CV for targeting bombs.
- tal8d 6y agoSo I guess you've never heard of the AGM-62 Walleye, or anything else that came out of China Lake. Before you try backpedaling with some silly nonsense about how gating isn't real CV, maybe do a quick search through the journals that cover this stuff: aiaa would be a good start. Another path would be in relation to counter-counter-measures, and ground noise rejection for air-to-ground radar guided munitions. That stuff was deployed regularly all the way back to Vietnam.
- marcinzm 6y agoAs the name RAD750 indicates, that processor is designed to be radiation hardened which matters for longer missions. I doubt the Snapdragon 801 will survive as long or have as few errors but it also doesn't matter since Ingenuity isn't aimed for long term usage.
- Robotbeat 6y agoIt’s less about longevity and more about reducing errors. Interestingly, Ingenuity has some sort of watchdog that can reset the Snapdragon in-flight fast enough to recover if there is an error.
- EarthLaunch 6y agoReminds me of SpaceX or Erlang; build a process that handles errors rather than an error free process.
- NikolaeVarius 6y agoI mean its space. Any computer expected to be in space and do non completely trivial things have tons of mechanisms in place to survive computer issues.
- deleted 6y ago[deleted]
- ddingus 6y agoPresumably. That is all part of this test.
- jjoonathan 6y agoReminds me of Apollo 11, where the computer kept resetting on the way down to the lunar surface but still got Neil Armstrong and Buzz Aldrin to the moon with the whole world watching.
- kabdib 6y ago
- samfisher83 6y agoIn general the older nodes work better for radiation and other cosmic forces. https://en.m.wikipedia.org/wiki/Radiation_hardening https://en.m.wikipedia.org/wiki/Radiation_hardening That's why they don't use the latest and greatest in the space.
- Robotbeat 6y agoThey work better primarily because they had previously invested in the tooling to rad-harden them and it’s really expensive to do that again one time for each mission; cheaper to rely on already-rad-hardened designs.
- jessriedel 6y agoDoesn't radiation mostly cause random one-off errors rather than permanent defects? If so, then if the rad-harden stuff is 100x slower (which I think is approximately right?), it is almost certainly better to use error correction on non-rad-hardened hardware.
- londons_explore 6y agoMany types of bit error are not recoverable without a full system reset. It isn't a matter of a simple "this bit in ram got corrupted", but more "this floating point unit has got into a state where it will not produce a result, and will therefore hang the entire processor". Therefore boot time becomes critical - if you end up rebooting due to bit errors multiple times per second, you can't afford to wait for Linux to start up each time...
- darknavi 6y ago> communicates with Perseverance using the Zigbee protocol I hope they installed the Home Assistant Core docker container on Perseverance. Gotta get those sweet dashboards.
- raverbashing 6y agoIt seems other parts are more modern. Yes, the main processor is a RAD750, but the peripherals can use modern components and there's some USB and Ethernet here and there (like the cable between the sky crane and the rover) Reliability is very important and space is harsh. I assume on the surface the radiation levels are low enough for Earth systems to work (maybe playing a bit with voltage/clock frequency helps, not sure how much shielding they can add, probably not too much).
- samstave 6y agoIf you were to build the exact same helicopter here based on those parts what would be the cost vs what’s the device on Mars cost? Also, I know plenty of solid engineers who I could build one thing based on that, obviously not taking atmosphere and G-forces into account to get there. Also Linus finally got his progeny to Mars. That’s a pretty cool accomplishment: “What have you built?” Well, I invented one of the most prolific operating systems the world has ever seen, but not just this world - there is a helicopter on Mars that is flying due to the seeds which I planted that day...” What have you built?
- kingo55 6y agoIt's not just atmosphere and g-forces. The cold temperatures mean the helicopter spends 2/3 of its battery power keeping the batteries and electronics from freezing. Good rundown of how it was built: https://www.youtube.com/watch?v=GhsZUZmJvaM https://www.youtube.com/watch?v=GhsZUZmJvaM
- dehrmann 6y agoIt's nice that NASA isn't falling victim to not-invented-here. If a commodity part or protocol can do the job, no sense reimplementing it.
- tomerico 6y agoThe problem is that NASA is designed around long term and expensive projects. At one point, a fast iterating company like space-x will surpass their achievements.
- mhh__ 6y agoWhy would SpaceX bother doing science, though? If you imagine a project like Voyager, you might think they just dump the data and "go home" (not quite, obviously) but to analyse the data and to know what to look for they had to hire geologists and meteorologists (for example) along with the planetary scientists and co. NASA should be about long term and expensive projects, SpaceX is just a tool to achieve that goal which is to do new science regardless of whether it is in the air or in space.
- newsbinator 6y agoSpaceX will do any science that’s profitable in the near/mid term
- alexvoda 6y agoMusk will do everything to achieve his dream of colonising Mars.