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A thought on MER longevity
SFJCody
post Apr 27 2006, 10:06 PM
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It's not completely impossible that one or both MERs could be in a semi-functional state by the time MSL lands in 2010.
If this happens, 3rd Jan 2004 might just go down in history as the last date on which humanity didn't have a working asset on the surface of Mars...
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JRehling
post Apr 27 2006, 10:37 PM
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QUOTE (SFJCody @ Apr 27 2006, 03:06 PM) *
It's not completely impossible that one or both MERs could be in a semi-functional state by the time MSL lands in 2010.
If this happens, 3rd Jan 2004 might just go down in history as the last date on which humanity didn't have a working asset on the surface of Mars...


That is interesting, but I'm more optimistic about the MERs' longevity than I am about the resources Mars exploration will get in the coming decades after, say, the next two. I think what happened to lunar exploration in 1972 will happen to Mars exploration sooner or later.
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Joffan
post Apr 27 2006, 10:49 PM
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Interesting thought... and worrying comparison with the Moon, where we haven't had any active hardware on the surface for ages and orbiters come and go.

What is the corresponding date for Mars orbiters? Did MGS start the current continuous coverage, or did she overlap with an earlier working bird?
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djellison
post Apr 27 2006, 10:52 PM
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There was a gap post-Viking-orbiter and pre-MGS - but there has been continual mars orbital coverage (allowing for aerobraking obviously ) since MGS's arrival

Doug
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tedstryk
post Apr 27 2006, 11:01 PM
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QUOTE (Joffan @ Apr 27 2006, 10:49 PM) *
Interesting thought... and worrying comparison with the Moon, where we haven't had any active hardware on the surface for ages and orbiters come and go.

What is the corresponding date for Mars orbiters? Did MGS start the current continuous coverage, or did she overlap with an earlier working bird?


Yes, it seems like a distant nightmare, but after the Viking 1 Orbiter mission ended on August 17, 1980, there was a gap until MGS arrived on September 11, 1997, with the exception of January 30 - March 27 1989, when Phobos 2 was operating in Mars orbit. As for landers, after the November 1982 loss of the Viking 1 lander due to a command error, there was the gap until July 2004. So between the early 80s and mid-to-late 1990s, there was a real drought, and I see no reason it couldn't happen again.


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djellison
post Apr 27 2006, 11:12 PM
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QUOTE (tedstryk @ Apr 27 2006, 11:01 PM) *
As for landers, after the November 1982 loss of the Viking 1 lander due to a command error, there was the gap until July 2004.


SLAP

http://mpfwww.jpl.nasa.gov/MPF/index1.html

smile.gif

Doug
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Bjorn Jonsson
post Apr 27 2006, 11:15 PM
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I'm convined that sooner or later there will again be no functional spacecraft at Mars for some time, i.e. neither an orbiter nor a lander. Possibly within 15 years.
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tedstryk
post Apr 27 2006, 11:19 PM
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QUOTE (djellison @ Apr 27 2006, 11:12 PM) *


To be fair, note that I said JULY 2004, not January...If only I put 1997. I mixed mixed the two dates..ughh..this is what grading finals will do to you rolleyes.gif


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edstrick
post Apr 28 2006, 11:04 AM
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Note that while VL-1 was apparently lost due to a command error, telemetry downloaded during periodic "continuation automatic mission" (I think that was the term) indicated battery failure was immanent. VL-2 was declared effectively dead when it suffered battery failure and attempts to run the tape recorder to playback data resulted in an undervoltage and spacecraft safing. Very shortly later, VO-1 died and VL-2 lost it's link to Earth. (Both direct-to-earth transmitters on VL-2 had failed).

VL-1 probably ended up in the same state, possibly during the recovery commanding attempts after command error (probably) screwed up antenna pointing during automatic downlink attempts.
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ljk4-1
post Apr 28 2006, 01:23 PM
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QUOTE (edstrick @ Apr 28 2006, 07:04 AM) *
Note that while VL-1 was apparently lost due to a command error, telemetry downloaded during periodic "continuation automatic mission" (I think that was the term) indicated battery failure was immanent. VL-2 was declared effectively dead when it suffered battery failure and attempts to run the tape recorder to playback data resulted in an undervoltage and spacecraft safing. Very shortly later, VO-1 died and VL-2 lost it's link to Earth. (Both direct-to-earth transmitters on VL-2 had failed).

VL-1 probably ended up in the same state, possibly during the recovery commanding attempts after command error (probably) screwed up antenna pointing during automatic downlink attempts.


So those old rumors about NASA purposely messing with the
Viking 1 lander to make it shut off and thus save money (there
was talk back then about it working until 1994) were just rumors?

I recall the Smithsonian National Air and Space Museum setting up
a monitor display to show images sent back from Viking 1 that
either never happened or quickly went away after the lander
shut down permanently.


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and feel as if I had done some wrong, and it is hard to forget the ugly circumstance.
I see that such intercourse long continued would make one thoroughly prosaic, hard,
and coarse. But the longest intercourse with Nature, though in her rudest moods, does
not thus harden and make coarse. A hard, sensible man whom we liken to a rock is
indeed much harder than a rock. From hard, coarse, insensible men with whom I have
no sympathy, I go to commune with the rocks, whose hearts are comparatively soft."

- Henry David Thoreau, November 15, 1853

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gpurcell
post Apr 28 2006, 05:48 PM
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QUOTE (Bjorn Jonsson @ Apr 27 2006, 11:15 PM) *
I'm convined that sooner or later there will again be no functional spacecraft at Mars for some time, i.e. neither an orbiter nor a lander. Possibly within 15 years.


I don't know about this. There is so much active hardware up there now (two MERs, MGS, Odyssey, MRO, and Mars Express with MSL and baby-MTO to come) that you would have to go a couple of decades before it ALL failed. I just don't see that happening. We may not have hit the point of permanent landed monitoring of Mars, but I don't think we will ever see a time without at least one functioning orbiter.
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Stephen
post May 5 2006, 01:36 AM
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QUOTE (SFJCody @ Apr 27 2006, 10:06 PM) *
It's not completely impossible that one or both MERs could be in a semi-functional state by the time MSL lands in 2010.
If this happens, 3rd Jan 2004 might just go down in history as the last date on which humanity didn't have a working asset on the surface of Mars...
That raises the question of how long the RTG(s) on the MSL are expected last.

Obviously that issue will be complicated by such factors as how much plutonium fuel they allocate the MSL and how power usage is juggled as the RTG(s)' power level declines.

But putting such complications aside, and assuming no calamitous hardware failures (or operator blunders), what would be the minimum number of months or years--beyond the main mission, I mean--we could expect from an MSL with all instruments running?

======
Stephen
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RNeuhaus
post May 5 2006, 02:34 AM
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QUOTE (Stephen @ May 4 2006, 08:36 PM) *
That raises the question of how long the RTG(s) on the MSL are expected last.

Obviously that issue will be complicated by such factors as how much plutonium fuel they allocate the MSL and how power usage is juggled as the RTG(s)' power level declines.

But putting such complications aside, and assuming no calamitous hardware failures (or operator blunders), what would be the minimum number of months or years--beyond the main mission, I mean--we could expect from an MSL with all instruments running?

NASA is considering nuclear energy for powering the Mars Science Laboratory. The rover would carry a U.S. Department of Energy radioisotope power supply that would generate electricity from the heat of plutonium's radioactive decay. This type of power supply could give the mission an operating lifespan on Mars' surface of a full martian year (687 Earth days) or more and in extreme seasonal conditions such as those at high latitudes. NASA is also considering solar power alternatives that could meet the mission's science and mobility objectives.

Minimum is one Mars Year and then multiply by ....

Rodolfo
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climber
post May 22 2006, 11:49 AM
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As we're talking about MER longevity, note that in 3 more days, May 25th 2006, we'll have to celebrate :
1500 Sols over garenty!
Let Astro0 add something about this for our BBQ party!


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climber
post May 22 2006, 08:17 PM
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Interesting statistics from Jim Bell on a space.com interview published may 19th : http://www.space.com/missionlaunches/06051...ers_update.html
"Since the twin rovers independently landed on Mars in January 2004, Spirit’s cameras have taken about 82,000 pictures. Opportunity has taken about 71,500 pictures - for a total down-linked image data volume of about 19 gigabytes. Of these, 54,400 and 49,500 are the high-resolution Pancam images, respectively, Bell said."
Does somebody know the total download value on top of the 19Gb of images ?


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