Naked Science Forum

Non Life Sciences => Technology => Topic started by: syhprum on 14/11/2014 22:31:20

Title: How should Rosetta's Philae lander best manage its energy supplies?
Post by: syhprum on 14/11/2014 22:31:20
I should not presume to tell the ESA team how to operate their comet lander but I am surprised that if it is receiving maybe 20% of the anticipated sunlight needed to maintain its batteries charged could not all scientific programs could be shut down leaving enough power to maintain communications until the comet gets closer to the sun.
Title: Re: Philae power budget
Post by: CliffordK on 15/11/2014 04:19:45
That sounds like it would be literally playing with fire.  As the comet approaches the sun, the surface of the comet will get warmer, and perhaps much less stable as the ice begins to evaporate. 

It is also not well anchored to the surface.  Will there be steam jets that could literally blow it off of the surface?

Actually, I think "approaching the sun" would be a bit of a misnomer as it will be approaching essentially the Earth/Moon's orbit.  So, one should expect maximum temperatures around 123°C during the day, and -233°C at night.  What is the comet made out of?  I could imagine the surface getting a little soupy 12 hrs a day, then hard as a rock for 12 hours a night.  Does the lander float?

Are there meteor impacts?

Anyway, I would expect them to budget the power to use run as many experiments as quickly as possible without fully draining the main batteries.  Communication should be with the orbiter, so it shouldn't take too much extra power, but they may choose to do it in data bursts.
Title: Re: Philae power budget
Post by: syhprum on 22/11/2014 19:31:27
Apparently the control of the power allocation system was one of several things that failed, I think the designers of the computer system might have a few questions to answer but perhaps they were starved of funds.
Title: Re: Philae power budget
Post by: CliffordK on 23/11/2014 19:21:02
It seems disappointing that after a long mission, the probe apparently failed in collecting a single sample from the surface of the comet. 

Does it have two battery banks, a main bank, and a "solar" bank?  Perhaps it is having troubles with the secondary bank.  Hopefully some of the issues will be worked out as it gets closer to the sun.