[FPSPACE] Spirit rover's power is running down, due to dust storms
agzak at optonline.net
agzak at optonline.net
Wed Nov 12 11:11:50 EST 2008
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).
----- Original Message -----
From: Peter Pesavento <pjp961 at svol.net>
Date: Wednesday, November 12, 2008 11:02 am
Subject: [FPSPACE] Spirit rover's power is running down, due to dust storms
To: fpspace at friends-partners.org
> >From the Los Angeles Times
> NASA's Mars rover Spirit imperiled by dust storms
> The craft is dangerously low on power because of dust covering its
> solararrays. News of the problem comes a day after NASA declared an
> end to the
> Phoenix polar mission.
> By John Johnson Jr.
> November 12, 2008
> Massive Martian dust storms are threatening the survival of NASA's
> Spiritrover, which has been exploring Mars for almost five years
> but is
> dangerously low on power.
> Spirit last communicated with Earth on Sunday, when it reported
> that its
> solar arrays had produced just 89 watt-hours of energy, which is
> much less
> than the rover uses in a day.
> It's also the least amount of power that either Spirit, or its twin,
> Opportunity, has produced over the entire life of the mission on
> Mars, which
> began in January 2004.
> John Callas, the rover project manager at the Jet Propulsion
> Laboratory in
> La Cañada Flintridge, said the rover's survival might be in
> jeopardy because
> the dust-covered arrays were producing only a third as much power
> as they
> were capable of, even before the latest dust storms hit. The storms
> of the
> last few days have reduced the output even more, to 26.5%, he said.
> The announcement of Spirit's problems came a day after NASA
> declared an end
> to the Phoenix mission near Mars' north pole, the first to sample
> ice on an
> alien planet. Dust storms, and the approach of winter in the northern
> hemisphere, are blamed for Phoenix's demise.
> As for Spirit, Callas said he believed the low power levels
> probably tripped
> a built-in fault-protection system, which automatically disconnects
> nearlyall the rover's electronics from its batteries to keep them
> from draining
> When that happens, mission managers on Earth lose control of the
> Ideally, after a low-power shutdown, the rover will periodically
> check to
> see whether the batteries have recharged. If they have, it resumes
> "The best chance for survival for Spirit," Callas said, is to avoid a
> low-power shutdown, from which it might not awake.
> To avoid draining the batteries, mission managers sent a message to
> therover Tuesday, ordering it not to communicate with Earth until
> By then, NASA officials hope, the dust storms will have cleared and
> thesolar panels will be producing more power.
> After spending much of the southern hemisphere winter parked,
> Spirit had
> only started driving again when the dust storms hit.
> The rover is currently halted at a geological feature called Home
> Meanwhile, Opportunity, which has not been compromised by the dust
> storms to
> the same extent, is driving to a deep crater.
> The rovers have far outlasted their original life expectancy of 90
> During their time on Mars, they have drilled into rocks and taken
> picturesof erosion patterns that proved that large parts of the Red
> Planet were once
> covered by seas or lakes.
> Today, the surface is much too cold for water to be in liquid form,
> scientists say.
> Scientists are now using the rovers to understand how the planet
> changedfrom a more temperate world to a barren rock.
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