Crowdfunded, Solar-powered Spacecraft Goes Silent

Last week saw the successful launch of the Planetary Society's LightSail spacecraft, the solar-powered satellite that runs Linux and was crowdfunded on Kickstarter. The spacecraft worked flawlessly for two days, but then fell silent, and the engineering team has been working hard on a fix ever since. They've pinpointed the problem: a software glitch. "Every 15 seconds, LightSail transmits a telemetry beacon packet. The software controlling the main system board writes corresponding information to a file called beacon.csv. If you're not familiar with CSV files, you can think of them as simplified spreadsheets—in fact, most can be opened with Microsoft Excel. As more beacons are transmitted, the file grows in size. When it reaches 32 megabytes—roughly the size of ten compressed music files—it can crash the flight system." Unfortunately, the only way to clear that CSV file is to reboot LightSail. It can be done remotely, but as anyone who deals with crashing computers understands, remote commands don't always work. The command has been sent a few dozen times already, but LightSail remains silent. The best hope may now be that the system spontaneously reboots on its own.

Comments

Re:Professional Level FUBAR

[Anonymous Coward]

I say professional because NASA screwed up a few years back with a probe to Mars when two systems attempted to communicate. One "spoke" in Kilometers, the other "Miles".

Actually this particular failure wasn't as obvious of an oversight as you may think. The reason it happened was because in an existing system one particular set of parameters were logged in miles since they weren't responsible for flight control (which NASA mostly uses metric for). Later on portions of this design were reused and an engineer decided to use the originally non-essential values as a feed into the navigation system.

The problem in this case is when you have something large and complex (a space craft) and a large organization with many projects (NASA/JPL) the younger generation tends to just rely on what's in place without doing the research they should.

That being said there were many times this particular error could have been caught on the ground and weren't, and that's a process failure. The "process" should have caught it.

Now get off my lawn!

Re:CSV

[Megane]

To be fair, that was copypasta from TFA. And they carefully omitted the next sentence: "The manufacturer of the avionics board corrected this glitch in later software revisions. But alas, LightSail’s software version doesn’t include the update."

That still doesn't excuse a problem that would have been found by bench-testing the thing for a few days before sending it up. Nor does it excuse constantly appending one file to store data in an unattended system. Also, anything that JPL sends up has a backup channel that can push that little red button on the main computer. All they can do now is hope for cosmic rays to reboot it randomly. At least it's in LEO and not zipping off into interplanetary space.

In the meantime, the team is looking at several fixes to work around the software vulnerability once contact is reestablished. One is a Linux file redirect that would send the contents of the troublesome beacon.csv file to a null location, a sort-of software black hole. Lab testing on this fix has been promising—over a gigabyte of beacon packets have already been sent into nothingness without a system freeze.

Well, isn't that special. Now they test it. So if they can just link it to /dev/null, did they really even need that data? It's always fun to cause a mission to fail by recording data that wasn't even needed.