Programming Error Doomed Russian Mars Probe

astroengine writes "So it turns out U.S. radars weren't to blame for the unfortunate demise of Russia's Phobos-Grunt Mars sample return mission — it was a computer programming error that doomed the probe, a government board investigating the accident has determined." According to the Planetary Society Blog's unofficial translation and paraphrasing of the incident report, "The spacecraft computer failed when two of the chips in the electronics suffered radiation damage. (The Russians say that radiation damage is the most likely cause, but the spacecraft was still in low Earth orbit beneath the radiation belts.) Whatever triggered the chip failure, the ultimate cause was the use of non-space-qualified electronic components. When the chips failed, the on-board computer program crashed."

Comments

Excuse me... not a programmer's fault.

[LostCluster]

We've got a contradictory summary here. Chip failure isn't a programming fault, it's a hardware problem. Stop confusing hardware and software you insensitive clod.

Fun to read the comments

[vlm]

Fun to read the comments here. I've done embedded stuff and you need to be defensive. You can see at a glance who here has never done defensive programming before, or embedded or safety critical programming, all blaming the hardware. There's 3 states so you got 2 bits of input and a disallowed state comes in. Deal with it, don't just curl up and die and blame the hardware designer. There's a 12 bit A/D conversion result stored in two bytes, and there's a 14 bit number found there, deal with it don't just curl up and die and blame the ... . Theres a cycle start button and an emergency stop button and both are simultaneously on. Deal with it. You reboot a mission critical (or safety critical!) CPU and a minor auxiliary input A/D doesn't initialize, do you burn the plant down in a woe is me pity party because one out of 237 sensors aren't coming on line, or do you deal with it?

Finally radiation is a statistical phenomena. There is no such think as radiation free. If they used non-rad hardened parts, its gonna crash maybe 10000 times more often. Thats OK, you program around that, assuming you know what you're doing. Radiation hardened does not equal radiation-proof. If there was a single bit error, or a latchup on a rad-hardened unit, with a poorly programmed control system it would have failed just as well, its just that a rad hardened chip would have made it a couple orders of magnitude less likely. A shitty design that has a 1 in 20000 failure rate due to better hardware instead of 1 in 2 is still a shitty programming design, even if the odds are "good enough" that it makes it most of the time with the better hardware.