[FPSPACE] Spirit rover's power is running down, due to dust storms

agzak at optonline.net agzak at optonline.net
Thu Nov 13 14:27:13 EST 2008


Interesting info on the MER pancam. I do realize engineers always try to minimize the number of moving parts in any machine, since they are the ones which would most likely fail. In the meantime, I checked some renderings of the European ExoMars rover and it seems that its solar panels do rotate along a single axis, at least in its current "reincarnation":

http://esamultimedia.esa.int/images/aurora/EXOMARS/Exomars.24.10.jpg

I also heard Phobos-Grunt will be on the extreme power diet during its stay on Phobos and it would be interesting to find out if developers considered to give its solar panels the ability to track the sun:

http://www.russianspaceweb.com/phobos_grunt.html 
  
Anatoly Zak


----- Original Message -----
From: Rick Kline <kline at astro.cornell.edu>
Date: Thursday, November 13, 2008 12:44 pm
Subject: Re: [FPSPACE] Spirit rover's power is running down,	due to dust storms
To: fpspace at friends-partners.org

> Of course the obvious problem with rotating solar panels, or even 
> moving 
> the ones that are on the MER spacecraft is that any moving part can 
> stop 
> moving in the least desired position.  Sort of the Murphy's Law of 
> spacecraft operations.  This concept is the one behind the decision 
> to 
> make the MER Pancam lens covers stationary - since the camera bar 
> was 
> designed to tilt to allow for close and far range imaging, the 
> built-in 
> motion is used to lower the Pancam aperatures onto the covers, 
> rather 
> than moving the covers to the cameras, where they could jam.  
> Voyager 
> 2's scan platform was in danger of sticking, so once it was placed 
> in a 
> useful orientation, it was left there, and the spacecraft itself 
> was 
> slewed to track targets during the Neptune encounter.
> 
> Rick Kline
> Data Manager
> Spacecraft Planetary Imaging Facility
> 
> agzak at optonline.net wrote:
> > Many satellites are designed to rotate their solar panels to 
> maximize power input. The same type of device could take care of 
> dust accumulating on solar panels. During MER missions, flight 
> controllers did have to place the rover on the slope to maximize 
> power. It seems that making rotating solar panels is better 
> solution than reliance on winds in the Martian atmosphere.   
> >
> > Anatoly Zak
> > http://www.russianspaceweb.com
> >
> >
> > ----- Original Message -----
> > From: James Oberg <jameseoberg at comcast.net>
> > Date: Wednesday, November 12, 2008 11:31 am
> > Subject: Re: [FPSPACE] Spirit rover's power is running down,due 
> to dust storms
> > To: agzak at optonline.net, fpspace at friends-partners.org
> >
> >   
> >> The story was about a dust storm in the upper atmosphere causing
> >> an area-wide 'brown-out'.
> >>
> >> That's way beyond the range of any gas jets on the rover.
> >>
> >> The amazing longevity of the rover mechanisms -- even the TES 
> crystals>> which were supposed to shatter in the cold of the first 
> winter -- 
> >> tempts us 
> >> to
> >> re-design the original vehicle, armed with precognition. I 
> wonder 
> >> if the
> >> trade-off between some instrument left behind, replaced by a 
> solar 
> >> panel 
> >> cleaning
> >> device of equal weight and power consumption, would have led to 
> the 
> >> choiceof the cleaner. If so, it would have been the wrong 
> choice, 
> >> since it turns 
> >> out
> >> the martian atmosphere provides self-cleaning episodes at no 
> cost 
> >> to the 
> >> rovers.
> >> The science would have been sacrificed to no operational advantage.
> >>
> >> These rovers aren't going to live forever -- but they may 
> outlive 
> >> some of 
> >> us!
> >> Amazing, from all angles. But as for implications of future 
> vehicle 
> >> design -- that's
> >> another story.
> >>
> >>
> >> ----- Original Message ----- 
> >> From: <agzak at optonline.net>
> >> To: <fpspace at friends-partners.org>
> >> Sent: Wednesday, November 12, 2008 10:11 AM
> >> Subject: Re: [FPSPACE] Spirit rover's power is running down,due 
> to 
> >> dust 
> >> storms
> >>
> >>
> >> It seems that some relatively simple solutions such as rotating 
> or 
> >> blowing 
> >> solar panels with cold gas could resolve the problem and prolong 
> >> these 
> >> missions. I am wondering if anything like that is considered for 
> >> future 
> >> spacecraft. (Of course, placing an RTG on the rover eliminates 
> the 
> >> problem 
> >> altogether).
> >>
> >>     
> >
> >
> > _______________________________________________
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> > FPSPACE at friends-partners.org
> > http://www.friends-partners.org/mailman/listinfo/fpspace
> >
> >
> >   
> 
> -- 
> 
> *************************************************************
>   "Better to wave at a stranger than to ignore a friend."
> *************************************************************
> Rick Kline
> Data Manager, Spacecraft Planetary Imaging Facility
> 317 Space Sciences Building
> Cornell University
> Ithaca, NY   14853-6801
> USA
> 
> e-mail:                     Phone:          fax:
> kline at astro.cornell.edu  607-255-3833    607-255-9002
> web: http://astro.cornell.edu/facilities/SPIF.php
> *************************************************************
> 
> 

Anatoly Zak
http://www.russianspaceweb.com


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