I&#x27;m don&#x27;t completely agree with the fact that it&#x27;s called a &quot;software update&quot;. Reading different article about it, from what I understand, there was an initial error (software error probably triggered by an hardware error probably due to an upset due to radiation), but this error is not very important. A series of event from this error triggered the safe mode (that&#x27;s expected), and there was the critical problem.<p>They had updated parameter in the software describing the torque generated by each thruster (or the center of mass position, or the tensor of inertia, or parameters based on all this) These parameter are software parameters, but updating them is not updating the software. It&#x27;s software data, not software code.<p>Of course this does not change the fact that it is a critical error, but it&#x27;s not exactly software update (IHMO). It&#x27;s a configuration error. It&#x27;s strange that they didn&#x27;t see that in a simulator before updating them, but it&#x27;s possible that they may have used the same value in the part simulating the software and the part simulating the thrusters themselves.<p>(note: I&#x27;m working in the satellite on-board software&#x2F;attitude control domain, but not for JAXA, in Europe. Anyway at my current position, I must both test this kind of code, and the parameter used in the code. And checking the parameters is much more difficult, because you must be sure that everyone agree on everything. This includes a lot of basic stuff, but it&#x27;s a pain in the ass ;-) )<p>This pdf from JAXA is probably the initial source of all articles. <a href="http:&#x2F;&#x2F;global.jaxa.jp&#x2F;press&#x2F;2016&#x2F;04&#x2F;files&#x2F;20160428_hitomi.pdf" rel="nofollow">http:&#x2F;&#x2F;global.jaxa.jp&#x2F;press&#x2F;2016&#x2F;04&#x2F;files&#x2F;20160428_hitomi.pd...</a> I found it interesting to read, if you know how it works. I would of course prefer to have more detains. I always want more details. But it&#x27;s for the press...