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The article (nor the product page for the X280) doesn't say whether these chips are radiation hardened, or whether NASA is now more comfortable with software so
by garblegarble 4y ago
The article (nor the product page for the X280) doesn't say whether these chips are radiation hardened, or whether NASA is now more comfortable with software solutions to the difficulties of reliable computation in space.
If the latter, that seems (to a layperson) quite exciting, since more local processing capabilities will hopefully lead to more efficient use of the very limited radio bandwidth these missions have available at such vast distances.
- qbasic_forever 4y agoThe last mars rover and its drone run embedded Linux, the JWST runs javascript (not node.js though!). NASA is already working with much more powerful and capable software stacks.
- deelowe 4y ago> the JWST runs javascript What?! I'd like to know more about this. Does it have GC? I just can't fathom that being the case...
- lifthrasiir 4y agoSee [1] (HN discussion: [2]). According to the paper [3] it looks like that it does have a GC and its resource usage is limited by other means. [1] https://www.theverge.com/2022/8/18/23206110/james-webb-space-telescope-javascript-jwst-instrument-control https://www.theverge.com/2022/8/18/23206110/james-webb-space... [2] https://news.ycombinator.com/item?id=32519918 https://news.ycombinator.com/item?id=32519918 [3] https://www.jwst.nasa.gov/resources/ISIMmanuscript.pdf#page=17 https://www.jwst.nasa.gov/resources/ISIMmanuscript.pdf#page=...
- acchow 4y ago> If you’re still worried, do note that the Space Telescope Science Institute’s document mentions that the script processor itself is written in C++ So they decided on Javascript back in 2006 and it uses an interpreter/runtime written in C++. Which runtime is this?
- deelowe 4y agoWow. Thanks!
- dotnet00 4y agoIts scripting engine for running commands sent from the ground is based on Javascript. So all the important stuff is done in native code, but the orders are taken in JS.
- nequo 4y agoIn an earlier era, NASA also sent Lisp to Mars.[1] And my understanding is that they sent it with GC. [1] https://corecursive.com/lisp-in-space-with-ron-garret/ https://corecursive.com/lisp-in-space-with-ron-garret/
- brucehoult 4y agoI can't fathom deploying anything critical WITHOUT GC. It's far too easy with malloc/free to make errors such as replacing a pointer with a pointer to another object and forgetting to free the original, freeing something that is still referred to somewhere else and then the other place using it and corrupting any new object allocated in that space, or freeing something that has already been freed, again potentially corrupting a new object reusing that memory. None of those is possible with GC. The only problem GC is subject to is allocating more data than you have physical memory for, and that is equally as much a problem with malloc/free so GC is no worse for that error, and better for the others.
- deleted 4y ago[deleted]
- gwd 4y ago> The only problem GC is subject to is allocating more data than you have physical memory for... On the contrary, the big issue with the GC is what happens when the actual collection happens. There's an apocryphal story about a research team that was making a table-tennis playing robot; but every 5 minutes the robot would randomly pause; in then end they discovered it was the Java garbage collector pausing the entire thing to run. Much less apocryphal, and more recently, Discord rewrote one of their services from Golang to Rust specifically because of the garbage collector [1]. Yes, misusing pointers is a potential problem; but when you're talking about situations where precise timing of maneuvering thrusters or stepper motors can make or break your mission, a garbage collector is arguably a much bigger problem if you don't have a way to make it predictable. [1] https://discord.com/blog/why-discord-is-switching-from-go-to-rust https://discord.com/blog/why-discord-is-switching-from-go-to...
- cestith 4y agoThere are predictable garbage collectors, though. Not every GC is a stop-the-world type. A good reference-counting system with the ability to weak-reference a variable can be pretty predictable and avoid loops as just one example.
- 4y ago
- tibbydudeza 4y agoThe rover still uses the radiation hardened PowerPC (RAD750 circa 2001 = 301K per CPU) but the drone uses a Snapdragon 801 SoC - it was not considered mission critical so the team could use off the shelf hardware. https://en.wikipedia.org/wiki/RAD750 https://en.wikipedia.org/wiki/RAD750
- UltraViolence 4y agoThe MARCO Mars satellites also used COTS components and computers, all running Linux. The worked great AFAIK. They even had a cheap COTS breakout-board camera which snapped a couple of pictures of Mars!
- tibbydudeza 4y agoThey are experimental and low cost (183 million USD) Cubesats - a great way to get educational institutions involved in space exploration without the backing of a NASA budget.
- ThinkBeat 4y agoexcept that the more complexity you add and make available the more things can break and go wrong. I imagine it is an interesting balancing act.
- _joel 4y agoMore over, Inginuity uses COTS altimeter from Sparkfun, it's still working!
- robocat 4y agoCOTS = Commercial Off The Shelf
- lizknope 4y agoWhere are you reading that? The Perseverance rover uses the VxWorks real time OS from Wind River Systems and the same RAD750 PowerPC processor that NASA has been using for the last 20 years. The rover is designed to last and operate a long time. The Ingenuity drone helicopter uses an off the shelf Qualcomm Snapdragon 801 and Linux. While NASA wants it to last a long time that was not part of its main design. https://www.pcmag.com/news/linux-is-now-on-mars-thanks-to-nasas-perseverance-rover https://www.pcmag.com/news/linux-is-now-on-mars-thanks-to-na...
- pkaye 4y agoThe helicopter uses an RAD hardened FPGA for handling the flight computation while the Snapdragon handles the less critical stuff. I'm guessing if the Snapdragon faults out, the flight computer will slowly descent and go idle.
- dontlaugh 4y agoI remember reading there is a system for detecting crashes and restarting it.
- _joel 4y agoIt's not hardened, they have 2 synced systems effectively that can pick up from each other, such that, if there's a bitflip, it can restart and switch over in less that the time it takes for a loop (kinda) so it can easily do this is mid-air with no loss of alititude or positioning.
- noselasd 4y agoWell almost. The Perseverance rover runs vxworks, like most if not all of its predecessors. Ingenuity (the drone/helicopter) does indeed run linux.
- deleted 4y ago[deleted]
- jpm_sd 4y agoSiFive is fabless. Looks like they will be collaborating with Microchip on actual production. https://www.nasa.gov/press-release/nasa-awards-next-generation-spaceflight-computing-processor-contract https://www.nasa.gov/press-release/nasa-awards-next-generati... https://www.electronicdesign.com/technologies/embedded-revolution/article/21248869/electronic-design-microchip-lands-deal-to-develop-new-spaceflight-processor-for-nasa https://www.electronicdesign.com/technologies/embedded-revol...
- mzs 4y agoI see Microchip doing nothing but ARM in this space and only SiFive folks quoted in their PR: https://www.microchip.com/en-us/products/microcontrollers-and-microprocessors/32-bit-mpus https://www.microchip.com/en-us/products/microcontrollers-an...
- jpm_sd 4y agoThis lays it out more explicitly: https://www.eenewseurope.com/en/microchip-to-develop-next-generation-space-processor-for-nasa/ https://www.eenewseurope.com/en/microchip-to-develop-next-ge... "NASA’s Jet Propulsion Laboratory has selected Microchip to develop the High-Performance Spaceflight Computing (HPSC) processor that will provide at least 100 times the computational capacity of current spaceflight computers for all types of future space missions, from planetary exploration to lunar and Mars surface missions. The radiation hardened, fault tolerant processor will be based on 12 instantiations of the X280 RISC-V core from SiFive and will be used in a series of ruggedised radiation tolerant single board computers." Microsemi (acquired by Microchip) has built RISC-V hardware in the past: https://www.electronicdesign.com/technologies/iot/article/21808869/microchip-delivers-riscv-hardcore-fpga-socs https://www.electronicdesign.com/technologies/iot/article/21...
- adgjlsfhk1 4y agoIn general, the design has gone towards have 3 to 5 redundant non-hardened computers with ECC that compare results and if one computer disagrees, restart it. Radiation hardening makes sense when computers cost tens of thousands, and weigh 10s of pounds, but now they are cheap, and only weigh a few grams.
- duskwuff 4y agoSiFive X280 is an IP core, not an IC. The design itself isn't inherently radiation-hard, but there's nothing preventing it from being manufactured on a radiation-hard process.
- mmaunder 4y agoAnd yes, having more onboard processing will lead to more pre-processing capabilities for data before it's sent/received via precious and limited DSN bandwidth. Could also allow for a low quality preview and selective-send mode of operation.
- IshKebab 4y agoThere are definitely things you can change in the design to make it more radiation-proof. ECC memory for example, logic sanity checks etc.
- noselasd 4y agoThere certainly things you can do in the design to be radiation hardened, it's not just in the manufacturing. The LEON [1] processor, initally designed by ESA for space missions incorporates quite many countermeasures in its IP core. [1] https://en.wikipedia.org/wiki/LEON https://en.wikipedia.org/wiki/LEON
- skissane 4y ago> incorporates quite many countermeasures in its IP core How hard would it be for SiFive to take one of their existing designs, which lacks those countermeasures, and add them?
- kramerger 4y agoHard but not impossible. Maybe too expensive to make sense for SiFive? IIRC, all internal logic will require triple mode redundancy and all type of memory will need ECC plus scrubbing.
- Someone 4y agoRelated NASA press release (I think): https://www.nasa.gov/press-release/nasa-awards-next-generation-spaceflight-computing-processor-contract https://www.nasa.gov/press-release/nasa-awards-next-generati.... That seems to say it’s for a radiation-hardened design: “In 2021, NASA solicited proposals for a trade study for an advanced radiation-hardened computing chip with the intention of selecting one vendor for development. This contract is part of NASA’s High-Performance Space Computing project” They also say: “The processor will enable spacecraft computers to perform calculations up to 100 times faster than today’s state-of-the-art space computers” and “Our current spaceflight computers were developed almost 30 years ago,” That, for me, also points towards a radiation-hardened design. If it isn’t, 100 times faster than 30 years ago is an incredibly low hurdle to clear. Also, it’s a $50 million firm-fixed-price contract. I have no idea whether that’s a sharp price for this, so can’t judge how much risk SiFive takes on with this.
- lizknope 4y agoNASA currently uses the RAD750 which is based on a PowerPC 750 that was new in Macs in 1997. https://en.wikipedia.org/wiki/RAD750 https://en.wikipedia.org/wiki/RAD750
- UltraViolence 4y agoThe newer designs aren't actually RAD-hardened, but fault tolerant. It's physically impossible to produce RAD-hard semiconductors at the small scale we're currently producing high-end CPU's with. I read this in an article somewhere but don't have the link.
- magicalhippo 4y agoSeems it's not quite as dire as one might imagine, for example the DAHLIA project is using ST's 28nm FDSOI process[1]. In any case, I found this[2] article interesting and illuminating, which goes into different aspects of radiation hardening, including how the "old = safe" isn't strictly true. [1]: https://dahlia-h2020.eu/about-project/ https://dahlia-h2020.eu/about-project/ [2]: https://habr.com/en/post/518366/ https://habr.com/en/post/518366/
- 4y ago
- tablespoon 4y ago> The article (nor the product page for the X280) doesn't say whether these chips are radiation hardened, or whether NASA is now more comfortable with software solutions to the difficulties of reliable computation in space. > If the latter, that seems (to a layperson) quite exciting, since more local processing capabilities will hopefully lead to more efficient use of the very limited radio bandwidth these missions have available at such vast distances. Is that either/or, though? I could imagine building a probe with a radiation hardened central processor (or two), plus a non-radiation hardened "accelerator" CPU that's not considered mission critical. The "accelerator" could be tasked with things like pre-transmission data analysis/triage, and if it fails the mission could continue without feature (like Galileo continued without its high-gain antenna). Though the value of that might be less than it seems at first look: New Horizons had literal years of time to transmit its data back to Earth.
- silasdavis 4y agoWhat is radiation hardening of chips? Stuff on the outside to absorb? Different band gaps in the silicon?
- Jtsummers 4y agohttps://en.wikipedia.org/wiki/Radiation_hardening https://en.wikipedia.org/wiki/Radiation_hardening Larger node, different substrate, shielding, and other things.
- silasdavis 4y agoThanks. Is this always an energetic issue, like the bit gets flipped or is it about long term material changes?
- jpgvm 4y agoBoth but primarily the former.
- rawoke083600 4y agoI always wondered can "you not just" dumped a your modern'ish pc in big bucket of mineral oil to fight of the radiation ? Given that water (and other hydrocarbons has been suggested as a shield material for cosmic radiation). As I understand It Cosmic Radiation is the bigger enemy than the "normal" beta/gamma radiation ?