4 ms·
This is the key passage: The spacecraft then automatically switched into a safe mode and, at about 4:10 a.m., fired thrusters to try to stop the ro
by dwc 10y ago
This is the key passage:
The spacecraft then automatically switched into a safe
mode and, at about 4:10 a.m., fired thrusters to try to
stop the rotation. But because the wrong command had
been uploaded, the firing caused the spacecraft to
accelerate further. (The improper command had been
uploaded to the satellite weeks earlier without proper
testing; JAXA says that it is investigating what
happened.)
Going into safe mode is a thing. It happens with NASA stuff, ESA stuff, whatever. The spacecraft failed to stabilize and went into safe mode, and that's proper. Whatever glitch in the systems, this would have saved it and allowed for recovery.
But the uploaded command to shed rotational velocity was wrong. This is what caused the loss of the spacecraft. I'm sure there will be a pretty heavy postmortem on how this happened.
- quadrature 10y agoI would not want to be in that PR.
- azernik 10y agoThe more striking thing to me is the long failure cascade before that, mostly hardware failures: the star tracker that glitched over the South Atlantic Anomaly, the gyro that reported a nonexistent spin, and the reaction wheel that didn't spin down properly.
- ww520 10y agoIsn't there a parallel simulator on the ground to try out the commands to see the effect before hand?
- rtkwe 10y ago> The improper command had been uploaded to the satellite weeks earlier without proper testing All the available testing programs in the world doesn't matter if the tests aren't run.