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Comment by csdreamer7 | Hacker News Reader

On Jupiter Broadcasting there was a lot of interviews on how this was a Linux powered device and could be the first of many new Linux devices on Mars by JPL. If I remembered correctly they used a space hardened Power cpu with an ancient version of Yocto since the newer versions of it did not have working drivers. When the rover had an issue they actually used the helicoptor's userspace command line GNU utilities to debug and get logs from the rover to send to Earth.

Also, this makes Mars the second planet that uses Linux more than Windows as noted by the tweet in the linux below. :-)

https://www.theverge.com/2021/2/19/22291324/linux-perseveran...

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The space-hardened POWER CPU was in Perseverance.

Some info from Wikipedia:

> The rover's computer uses the BAE Systems RAD750 radiation-hardened single board computer based on a ruggedized PowerPC G3 microprocessor (PowerPC 750). The computer contains 128 megabytes of volatile DRAM, and runs at 133 MHz. The flight software runs on the VxWorks operating system, is written in C and is able to access 4 gigabytes of NAND non-volatile memory on a separate card.

> When the rover had an issue they actually used the helicoptor's userspace command line GNU utilities to debug and get logs from the rover to send to Earth.

Wow, such a great testament to The Unix Philosophy of building small, modular, focused tools that can be combined together to do all sorts of interesting and more complex tasks. I'm sure no one imagined using these utilities from a helicopter to retrieve rover logs to aid in diagnostics, but here we are. What a cool story.

now if we just teach those tools to kids instead of turning them into spreadsheet office robots, that would be great.

I imagine NASA is built and operated on a foundation of thousands of spreadsheets

Spreadsheets are the best thing in computing since a Lisp REPL. Half of the startups today would be much better (in terms of utility, simplicity and ergonomics) for users and customers if they were served in form of a downloadable Excel sheet.

Almost agree, 'xcept for the "Excel" part, which I would switch against "spreadsheet".

Fun fact - the cameras that captures Perseverance's landing are also Linux based and vim is installed - at least on the later model that I worked with.

Hopefully some engineer on the ground used Emacs to access the command line remotely, to run Vim, so that we are back on equal footing :D

What make & model of camera are these?

They're USB cameras. I don't know the vendor, but I worked with 4 cameras wired back to a small Linux computer.

FLIR Chameleon3 connected via USB to a Intel Atom Linux SBC running ffmpeg to encode the video.

See EDLCAM in https://link.springer.com/article/10.1007/s11214-020-00765-9

I am really surprised they are using essentially off-the-shelf USB cameras. I guess if it works, it works, but surprising that they didn't need to design circuitry to work in a space environment.

I am guessing the requirements for circuitry operating on Mars isn't quite as much as a spacecraft or satellite, but it is still getting hit with cosmic particles and solar radiation with no atmosphere.

Using it with a 20 minute delay between keystrokes and their results must be interesting

I'm sure they didn't connect to it via the internet to send keystrokes.

Huge delays between keypresses is what vi (and vim ofc) was designed for.

> If I remembered correctly they used a space hardened Power cpu

If you're remembering correctly, then I'm misremembering in that this has essentially a Snapdragon chip and not a rad hardened CPU at all

Maybe I am misremembering the interview. Maybe the person said that they used to use a hardened IBM power chip?

This information is pretty widely available, e.g. on Wikipedia [1], no need to go off memory. Flight control is done by an FPGA, the main CPU is a Snapdragon 801 running Linux, and it uses Zigbee to communicate with the rover.

[1] https://en.wikipedia.org/wiki/Ingenuity_(helicopter)#Avionic...

At least they won't have any trouble finding a free channel.

They used the hardened PowerPC for the rover, similar to previous mars rovers and the Snapdragon chip for the helicopter.

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