On Wednesday, 19 February 2014 at 05:53:55 UTC, Tolga Cakiroglu
wrote:
I think only knowing that it has failed is not enough. Because
the process is landing, and other CPU should know where the
process is left. With that heatbeat signal, only option is that
all sensor information must be sent both CPUs continuously and
sensor values should be enough about what next step to be
taken. Then I think it can continue the process flawlessly.
I don't think watching the video answered this, but it hinted
toward the second CPU being inactive during landing, if something
went wrong the CPU would need to be awoken at which point the
backup CPU would take in all the readings from different sensors
to decide on actions (possibly it is intended only to land the
rover and not land the rover in the correct location.)
What was interesting from the video is that the second CPU was
going to be turned off for the landing and not used as a backup.
A year before landing (I guess that means 3 months before launch)
they decided to create the backup software if the main CPU failed
during landing, it didn't.
