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What Re-born '01 Lander Platform?
dot.dk
post Jan 20 2005, 12:55 AM
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Is Phonix not the reborn '99 Polar Lander?

Just curios unsure.gif


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djellison
post Jan 20 2005, 09:18 AM
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It's the part-built 2001 lander, taken out of storage - Marie Curie taken off and other instrumentation bolted on.

If you add the money spent pre-cancellation, AND the money for the scout class mission - Phoenix is a rather expensive little lander

Doug
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tedstryk
post Jan 20 2005, 11:12 AM
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Indeed it will be. The advantage it has over missions of equal total cost is that so much of the money has already been spent. The chemistry results should be fascinating. Really, it is more of an awkwardly cobbled together major mission than a little scout, but it made sense considering what was already built. In 2011 we will see the first true scouts.

Ted


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dot.dk
post Jan 20 2005, 11:28 AM
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Why was the 2001 lander cancelled?

Was it because of the failure of the MCO and MPL?


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djellison
post Jan 20 2005, 11:55 AM
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Yeah - it shares most of the same systems - it's the same design really. Same engines, same systems, same structure, same cruise hardware etc. Because of that - when the '99 lander failure was not understood - the '01 lander was cancelled as a matter of caution.

The only majorly different things are the solar arrays and the instrumentation. Also - it's got an MER style HGA instead of the wok-design that MPL had - and this platform also had - and changed instrumentation.

The orig. plan was for the robot arm to 'pick up' the Sojourner 'spare' ( Marie Curie ) from the lander deck and put it on the ground beside the lander to rover around. That's since been dropped from the package.

Whilst some would say the platform is 'flight proven' w.r.t. Polar Lander - to be honest, the only thing that's proven is that it fails. However - the likely root cause has been found, and fixed ( a simple software bug ) - and they will be obliged to integrate some form of EDL tone telemetry a la MER to help troubleshoot if there is another failure.

The camera system is a hybrid evolution of the MPF/MPL camera ( 14.4 degree f.o.v. with approx 256 pixels across) and the MER CCD's ( 1024 across ) - so, if the two work well together, it should actually be better imagery - just - than MER biggrin.gif

Doug
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lyford
post Jan 21 2005, 12:23 AM
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QUOTE (djellison @ Jan 20 2005, 03:55 AM)
....The orig. plan was for the robot arm to 'pick up' the Sojourner 'spare' ( Marie Curie ) from the lander deck and put it on the ground beside the lander to rover around. That's since been dropped from the package.

I wondered what happened to the second one - Marie Curie is still mentioned on some websites that obviously haven't been updated for a while. tongue.gif

Any idea why the mini rover aspect was cut?


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tedstryk
post Jan 21 2005, 01:23 AM
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To make room for the MPL instrumentation.


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Guest_BruceMoomaw_*
post Jan 22 2005, 02:46 AM
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Yes -- that rover, tiny though it was, was pretty heavy compared to the other instrumentation that could be put on it -- and the other instrumentation, stationary though it was, was a lot more useful for this mission than the rover. Phoenix will focus more on vertical mobility -- that is, digging through subsurface layers -- than horizontal mobility.

Actually, the whole idea of Sojourner was yet another of Dan Goldin's harebrained personal brainstorms; it actually isn't all that scientifically useful because it can carry so little instrumentation (although the design may have some specialized uses, such as localized sample collection and return to the instruments on a stationary lander, as in the "Urey" Mars Scout proposal).

In that conenction, I picked up my latest Captain Crazy story at the NASA Mars Strategic Roadmap meeting. You'll recall that for some time, some NASA charts of the fundamental subjects of study on Mars listed only "Life", "Climate", and "Human Resources" -- without a mention of "Geology", although that is obviously the other subject of major interest about Mars. I wondered about this -- espeicially since other such charts, published at the same time, DID list "Geology".

Well, it turns out that the charts forbidding geology to be listed as a scientific subject in Mars exploration were the result of a direct personal order from Goldin, on the grounds that "geologists have too much influence over the Solar System exploration program already". However, since any sane discussion to set detailed priorities for Mars exploration obviously requires including geology, the other charts with it included were printed up and distributed to advisory groups behind his back! The whole thing is, once again, reminiscent of Captain Queeg -- or maybe of the Elders of Tittipu frantically digging up legal technicalities to try to avoid obeying the Mikado's lunatic commands. However, as one of the Committee's heads said (to a chorus of relieved chuckles), "Well, he's gone now."
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remcook
post Jan 22 2005, 10:36 AM
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QUOTE
Actually, the whole idea of Sojourner was yet another of Dan Goldin's harebrained personal brainstorms; it actually isn't all that scientifically useful because it can carry so little instrumentation


sojourner was never a science mission in the first place. It was a technology demonstrator. thanks to sojourner, there's now MER.
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djellison
post Jan 22 2005, 11:46 AM
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Yup - Sojourner was essentially a brilliant technological achievment and quietly, a scientific folly. It trundled around taking APXS measurements of the dust on top of rocks smile.gif

BUT - it was cool, it flight proved the 6 wheel rocker-bogey system, it demostrated that roving on mars IS possible, and it showed that a RAT was needed smile.gif Pathfinder was an interesting misson technologically as well. It demonstrated the brave EDL system - showed mars can be done for a lot less than Viking - and showed that space can be 'cool' in this Internet generation.

Something i'd quite like to do is a full re-creation of Sojourners drives around the landing site using the 3d model of the landing site and a rendered sojourner.

Doug
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Guest_BruceMoomaw_*
post Jan 22 2005, 11:52 AM
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As a technology demonstrator, Sojourner was pretty much of a red herring -- rovers can be tested every bit as well on Earth, and have been for a long time. Goldin insisted on Sojourner because -- as yet another of his idiotic personal snap decisions -- he happened to see a mockup of a tiny rover one day and immediately demanded that a full-scale program be run to see if such a tiny vehicle could provide science as worthwhile as an MER-sized one. It didn't. (Until then, Mars Pathfinder had been just a prototype test for a projected series of Mars network landers with stationary instruments.)

Goldin's insistence on a similarly miniaturized Pluto probe -- even though the technology wouldn't support it -- was, at least on the surface, responsible for the fact that the US didn't launch a Pluto prove in late 2003 that would have been (thanks to a different trajectory) both considerably cheaper and more scientifically capable than the 2006 version of New Horizons. However, I was told by a member of NASA's Solar System Exploration Subcommittee in 2000 that this was just Goldin's cover for the fact that he was determined not to fly a Pluto probe at all, because (to quote him) "Nobody gives a damn about Pluto."
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Guest_BruceMoomaw_*
post Jan 22 2005, 12:03 PM
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Let me add that:

(1) The rocker-bogey system had been thoroughly tested on Earth and confirmed to be the best possible rover design. (Without this, they would never have dared to put it on a mars rover of any size).

(2) We were already fully confident from our knowledge of Martian terrain and soil mechanics, obtained by the Viking landers, that we could rove on Mars -- and Sojourner provided no surprises or new information on this whatsoever.

(3) We were also well aware before Sojourner that Mars rocks had a dust layer -- and probably a weathered crust -- on them that must be removed to properly analyze their non-weathered composition. Sojourner would have carried one itself had it been able.

In short, despite the public's fondness for the cute little thing (and one can, I suppose, argue that its PR value for NASA made it worthwhile), Sojourner -- and, indeed Pathfinder in general -- turned out to be red herrings. Despite all the hoorahs for the latter's airbag landing system, NASA has no plans to use it again on anything but the tiniest possible network landers -- it turned out, in practice, to be much heavier than anyone had anticipated due to the need for very tough airbags, and it is still very dangerously vulnerable to crosswinds. It almost ruined the MER program for those reasons. The fully controlled throttleable rocket and multi-beam radar system used by the Lunar Surveyors, LMs and Vikings is the wave of the future for all future Mars landers of any significant size -- despite the fact that Polar Lander screwed up (entirely because of a chance flaw produced by Goldin's cretinous insistence on doing it for half as much as Pathfinder had cost).
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tedstryk
post Jan 22 2005, 01:07 PM
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Which, as I said in another group once, is why I think we should rename the Mars Polar Lander site the Dan Goldin Station.
Some science eventually did come from Sojourners APXS.
http://adsabs.harvard.edu/cgi-bin/nph-data...41f2517bea24567

http://adsabs.harvard.edu/cgi-bin/nph-bib_...41f2517bea24671

The biggest discovery was that the rocks appeared to have been exposed to water. Also, they seemed more chemically evolved than the SNCs. The problem was that it took untill 2003/2004 to analyze the date to the point that results could be determined...by which time Spirit and Opportunity were already on their way. Another interesting Pathfinder result was the discovery of striations at such a small scale that followed the direction of the flow of Ares Valles (conventional wisdom was that such things should have been destroyed by wind).

You have to remember that the Vikings never were able to pick up a rock. They thought they had at one point, but it proved to be a dirt clod that broke up. And yes, they did know that rocks were dusty, but they didn't realize how bad they would be (Marie Curie would have had a brush).

I think the Pathfinder results are pretty impressive, given the fact that it was only a technology pathfinder. I think it is a landing technique that may come in handy for network landers in the future. And it did give us a pretty good impression of a little patch on Mars, which is something we only have of four other places on that planet.


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lyford
post Jan 23 2005, 05:28 PM
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QUOTE (tedstryk @ Jan 22 2005, 05:07 AM)
Which, as I said in another group once, is why I think we should rename the Mars Polar Lander site the Dan Goldin Station.

Very funny!

My outsiders opinion was this about Goldin: He drank too much of the New Information Economy Kool Aid and thought that tech advances were going to give us squadrons of cheap matchbook size rovers on Mars in 5 years. But Moore's Law notwithstanding, Murphy's Law requires that you may only choose 2 of the 3 "Better Fast Cheaper," and I don't know how anyone with a mechanical engineering background could seriously believe that some of his goals were more than PR.

Though I can understand the advantages of focused mini missions, there is a certain cost of doing business in space, and nature deals us enough challenges without adding the extra burden of doing it on the cheap.

That being said, the MER missions really are cheap in my opinion. For less than the price of a B2 bomber each, we are driving on Mars for a year - maybe two!


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