Design, Hardware, Software Errors Doomed Japanese Hitomi Spacecraft (scientificamerican.com)

Reader Required Snark writes: The Japanese space agency JAXA said its recently launched X-Ray observation satellite Hitomi has been destroyed. After a successful launch on February 17, contact with the satellite was lost on March 28. Off the 10-year expected life span, only three days of observations were collected. Preliminary inquiry points to multiple failures in design, hardware and software. After the launch it was discovered that the star tracker stabilization didn't work in a low magnetic flux area over the South Atlantic. When the backup gyroscopic spin stabilization took control, the spin increased instead of stopping. An internal magnetic limit feature in the gyroscope failed, causing the spin get worse. Finally, a thruster based control started, but because of a software failure the spin increased further. The solar panels broke off, leaving the satellite without a long-term power supply. It seems that untested software had been uploaded for thrust control just before the breakup. This is a major loss for astronomical research. Two previous attempts by Japan to launch a high-resolution X-ray calorimeter had also failed, and the next planned sensor of this type is not scheduled until 2028 by the ESA. Just building a replacement unit would take 3 to 5 years and cost $50 million, without the cost of a satellite or launch.

Comments

3 days of data?

[JustAnotherOldGuy]

Only got 3 days of data? Damn, that's gotta hurt.

Also, the "Design, Hardware, Software Error" bit is funny in a way...I mean, what else was left to screw up? This was like the Trifecta of Fuckups.

Root cause analysis?

[drwho]

I'd like to see a more thorough investigation of this set of incidents. That means no one involved gets to skip out by Seppuku. One of the problems with having a number of backup systems is that people tend to think "well, if it breaks, there's a backup system" - not realizing that each time a backup system is added, complexity is added, and that overall reliability goes down, instead of up. I don't know if over-reliance of backup systems, and failure to manage complexity, was the cause here, but it's the only thing other than "bad luck" or "sabotage" that can explain this disaster from a country which has many talented engineers.