Mer 3 Possibility? Options

[Marslauncher]

I was just wondering about this, they have test rovers at JPL, which will eventually not be needed, they have a Proven EDL system and they have a few sites which were still MER rated (although I would like to see the one featured in Steve's book Roving Mars, where they land in Valles Marineris (I think that was right one of the Valles anyway) (solar power would suck though..) What would be the chances of using all the materials we already have and launching a new MER or pair of MER's in 2007?

They could upgrade some of the payload, based on results from the MER's data, must be something they wished they had.?

Just wondered.

How much would this cost?

[Cugel]

It's impossible.
The MER rovers were optimized for a boeing Delta-2 rocket and up until 2018 the coming Mars oppositions will be so bad that the Delta-2 can't lift the mass of a MER rover to Mars. Using another booster will be very costly.

Sorry.

[Marslauncher]

Thanks, however if and I know this is a big if the Falcon launch goes well, wonder if they would have a large enough launch vehicle in time for 2007

[dilo]

I strongly sponsorize this idea!
If a laucher is available, a relatively low-cost MER mission in Valles Marineris would be simply fantastic!

[vikingmars]

...And it's very hard to send to space equipment already used for testing. During the old days, JPL wanted also to use its spare Viking Lander on a new Mars mission that could have been sent in 1984 (dubbed "Viking III") with flexible crawl devices in place of the footpads, to gain some mobility... The mission was to use a direct entry on Mars, much like Pathfinder's and MER's (it was those preliminary entry studies that were used when the MESUR/pathfinder project begun...).
Finally there was no more budget for Viking III because of the launching cost... But also the VL s/c would have to be entilely dismantled, all s/c parts tested back and improved to be space-proof again, and rebuilt ! Unlike the 2001 Mars Lander, the spare VL lander was not shelved within a "space-clean" environment...
The same technical problems would arise for a "MER III"...

[Guest_BruceMoomaw_*]

The problems are:

(1) The MERs, unmodified, simply can't carry that many scientifically cost-effective science instruments. Their goal was to settle once and for all the question of whether ancient Mars had significant amounts of liquid water on its surface, which they did. There is that proposal (which JPL is still close-mouthed about) to modify a MER into a cut-price, scientifically inferior version of MSL ( http://www.lpi.usra.edu/meetings/lpsc2005/pdf/2219.pdf ) -- but this would take major modification. As they now stand, the instruments that could be added on could not actually ingest and grind up samples for a detailed search for trace organic compounds, which is now the next important phase of Mars exploration. You could add some things like a LIBS or a Raman spectrometer -- at the cost of removing some of the existing instruments -- but their usefulness by themselves is limited.

(2) You still have the serious problem of the MER landing system's extreme vulnerability to horizontal crosswinds -- which is what finally ruled out at least two landing sites in the bottom of Valles Marineris which would otherwise almost certainly have been picked for MER-A. As things are, it barely survived its landing in the less windy Gusev. To solve this, you've got to switch all the way over to a full-blown soft-landing system with throttleable liquid rockets directed by sophisticated radar -- but if you're going to make that sort of radical addition to an MER, why not go further and land an MSL (or some scientifically intermediate class of rover)?

[djellison]

The two engineering models sat on the ground here on earth have probably covered a LOT more ground than the ones on mars - they're probably very tired anyway.

I asked Steve about this in the Q'n'A and he believes it would be hard to do a third MER inside a Mars Scout budget of say $400M

Doug

[Marslauncher]

The original mission cost almost $800m, they have the design down, they have the parachute design down (which cost a lot to test referring to Roving Mars) all of the major cost points listed in Roving Mars have already been covered, I think one MER would have been in the ball park of $500m but the second was able to be done with $300m
Surely all of the parts for the MER's themselves dont cost $100m and a suitable launch vehicle I am sure could be found, In Steve's Book he mentioned the option of using Enterprise classed mission to launch a MER at the start, Is that option still available or have we succumbed to the Faster, Better, Cheaper designs? I just think that in the next 6 years it is a little long to wait for another mobile vehicle, to continue the dream of Exploration of Mars, to keep the publics attention, nothing keeps the publics attention like a Rover, I highly doubt there will be as much attention for Phoenix, and then what launches in 2009? that has yet to be decided. I vote we send at least one more MER to MARS, if not only to keep and maintain the publics interest, (Free Food at Long John Silver's if a MER found evidence of an ancient sea, They did comply with their end of the bargain)

I know we found evidence of water and that question has been answered, but to what extent, the floor of valles marineris would be an AWESOME place to search.

Send another MER and lets keep "Roving Mars"

John Cooke

[tty]

(1) As they now stand, the instruments that could be added on could not actually ingest and grind up samples for a detailed search for trace organic compounds, which is now the next important phase of Mars exploration.

(2)  You still have the serious problem of the MER landing system's extreme vulnerability to horizontal crosswinds -- which is what finally ruled out at least two landing sites in the bottom of Valles Marineris which would otherwise almost certainly have been picked for MER-A.  As things are, it barely survived its landing in the less windy Gusev.  To solve this, you've got to switch all the way over to a full-blown soft-landing system with throttleable liquid rockets directed by sophisticated radar -- but if you're going to make that sort of radical addition to an MER, why not go further and land an MSL (or some scientifically intermediate class of rover)?

(1) The MER already can grind up samples and has done so many times. Surely it would not be impossible to modify the instrument arm so it could scoop up some of the RAT droppings and deliver them to a hopper somewhere on the "deck"? It would presumably be rather more difficult to find place for an anlyzer unit, but probably not impossible.

(2) The TIRS system could fairly easily be upgraded, for example to 3 pairs of slightly smaller engines which would give a lot more flexibility in the size and direction of the sideways "kick".

tty

[djellison]

but probably not impossible.

What are you willing to drop to accomodate it in terms of volume, mass, power and data budget?

Doug

[JRehling]

The problems are:

(1)  The MERs, unmodified, simply can't carry that many scientifically cost-effective science instruments.
[...]
(2)  You still have the serious problem of the MER landing system's extreme vulnerability to horizontal crosswinds -- which is what finally ruled out at least two landing sites
[...]

While there is certainly some science return that could be had from a third MER, it is also certainly not the platform for the best next mission. The engineering limits are severe, and it should be noted that Spirit's success was a big counter to plan and somewhat lucky. Spirit's first 120 days were almost scientifically worthless, and if it had landed far from hills (as most of its ellipse was), it might have been a bust -- lots of basalt ejecta as far as the eye can see. Spirit's success in finding water was (probably) irrelevant to the purpose the Gusev landing site was chosen. Overall, we had a grand total of one landing site that met the considerable engineering constraints and scientific interest. These landing sites were chosen from list ranked by estimated interest, and we can already see the dropoff from #1 to #2.

A program intended to "geomorphology" the death out of Mars's tropics, and maybe luck into discoveries by serendipity could be had from the MERs and undoubtedly turn up a few gems per every so many missions... but this looks to be a loser in terms of cost effective space science. A craft that had a broader instrument package OR fewer engineering constraints (a MER to Athabasca Valles or the bottom of the Valles Marineris) would be a lot more likely to be a winner.

[mike]

If NASA/JPL had unlimited money, I'd say send another MER rover, but of course, it doesn't. Ultimately it is probably better to put the funds into a more capable platform, even if it does take longer.

Personally, I don't find grinding rocks all that interesting, except that there may be something hidden within, which hasn't obviously happened yet (depending on who you ask, I suppose). A MER with specifically biology-detecting instruments would be nice, but, you know, money. Go for the big rover that can do it all, I say.

[RNeuhaus]

I think that everybody wants to keep to be busy with Mars explorations for all-round years. Nobody wants to miss a gap of four years between 2008 (after Phonix) and 20011 that there were no land missions on Mars.

I seem important to keep the momentum of Mars Exploration in order to improve the knowledge and experience by the not missing years between 2008 and 2011. Sending a MER-C with the advantage of its present technology and some adjustments. These adjustments are to align to the MSL mission to explore and quantitatively assess Mars as a potential habitat for life, past or present.

The other important factor is the continuity of highly skilled personnel with mind, experience and knowledge that are oriented to Mars mission. If not, many will be leaving and later hiring will not be as good unless after a some time.

Hence, the MER-C would be an important exploration in order to improve the MSL's mission. The improvement is done with the experience and knowledge gain in order to make a much better investment on MSL. Hence it helps to NASA to gain four years of long term mission in sending a man to Mars.

Rodolfo

[Marslauncher]

Thought I would get a poll started just to get a numerical gauge.

Also if anyone could ask their friends at JPL what exactly would be needed to send a MER C that would be great.

[helvick]

What are you willing to drop to accomodate it in terms of volume, mass, power and data budget?

Doug

That's pretty tough. OK I'll bite

First - go after some "easy" targets to save mass and reduce power consumption.
Power
The power subsystem has proven to be much better than expected and although luck has played its part I think we could safely do the following:
Reduce Solar panel area by 20%, possibly 30%. Clearly we have more power during a 90day mission than is absolutely needed provided there is no major storm. Mission timing can ensure that the storm risk is very small. The cells on the rovers are very good by current commercial standards but the best on the market today are about 20% more efficient again (34% now vs 26.8% at best when the Rovers were built).
I've no numbers on the mass of the Solar panel arrays on the MER's but I seem to remember a number of 30W\kg ie, panel mass is ~4.5Kg and the saving would be 1kg.

Reduce battery mass by 25%. Current generation of battery technologies have twice the power storage density (250-350Whr/kg vs 100Whr/kg for the current MER's)
Saving 2.5kg?

Power Management and Distribution - MER was around 80-90% efficient @ 50W/kg. Estimate (in 2002) was 85-95% efficient @ 125W/kg by 2007. Should be able to shave off 1kg there by now.

Total saving on the Power system - 4.5kg

As a sanity check I've got an ESA document [ Lang ESA 2002 ] that seems to gravitate to 5W/kg total system power subsystem mass for solar power\LiIon systems. That could be 28kg total mass on MER and we should be able to save 20% ie. 5.5kg.

Add some extra RHU's to areas now known to be temperature risk spots. At 40g a pop we can certainly afford 2 or 3 to protect areas during deep sleep (such as the Mini-TES). Sensibly chosen these could make deep sleep the normal mode of operation and help bring the minimum power requirement for regular operation down to 300Watt hours per Sol provided we can save some more power(below).

So Saving 4.5kg should be manageable while still generating\storing > 2.5 times the minimum power needed for operations at the start of the mission.

Processing and Data Storage.
Update the CPU from a RAD6000 to a RAD750. The RAD6000 is rated @ 25MIPs with a peak power draw of 7.5 Watts. The 750 has a peak power draw of 5W @ 133Mhz yielding 240MIPS and far superior FP performance.

Those extra (and cheaper) MIPs should drop total daily power requirements by between 25Whr and 50Whr improving our safety margin. Replace the existing 256M flash with a couple of GB. Those extra MIPS could then be used to handle more advanced image processing in situ, buffer more data to optimise downlink windows and thereby save additional power on data transmission.

So far - we've only saved 4-4.5kg or so but we have an order of magnitude more CPU and storage capability. We also should have a rover that could handle much trickier terrain autonomously if some effort was put in to updating the flight software.

Additional instruments.
Mass Spectrometer Mars96\Beagle2 - 4.4kg total. 4Watts of power.
Atmospheric Pressure sensor - 16grammes, 36mW, <1Whr/Sol
Wind Sensor 30grammes. 200-600mW. 30grammes. 12Whr/Sol

One of these chirality detectors would be ideal but I've no idea how practical\heavy\power hungry they would be.