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Bruce Moomaw

Why should the ESA go for LANDERS at all? There's still a real potential for orbiters -- within the cost range that ESA can afford -- which could have real benefits. One possibility is a clone of MARVEL, to try to do a really good map of the distribution of methane and other biologically important trace gases across the Martian surface. (MARVEL was originally supposed to also carry a down-looking microwave spectrometer to precisely localize any such gases located by its IR solar-occultation spectrometer -- but that had to be given the boot because it would bust the Mars Scout price cap. The ESA might be able to include it.)

Then there's the possibility of a Mars-orbiting SAR to peer through the top few meters of windblown dust that have ubiquitously blanketed Mars' surface, concealing a great number of the likely watercourses and other geological features created during its habitable Noachian days -- another high-priority item, according to the US National Academy of Sciences' 2002 recommendations on future Mars exploration priorities. And it's one which might well be within the ESA's price range (there was at least one proposal to do it with a Mars Scout that got high ratings from the appraisal board, although it didn't make it into the list of four finalists).

And keep in mind that -- even after MRO and all its predecessors have flown -- there will still be a huge part of Mars that has NOT been mapped at very high resolution, either photographically or with mineral-composition IR maps (or IR searches for possible warm spots). There is still lots of potential work for Mars orbiters. It's clearer than ever that we need to do as much of such advance reconaissance as possible of Mars before picking the few spots where we'll be able to land big, expensive landers or sample-return vehicles -- and the amount of such vital reconaisssance that we can do by scattering small landers across the surface is very seriously limited. Airplanes, gliders or balloons are another possible alternative for this -- but the more of it we can do with high resolution instruments from orbit, the better. Mars Express, by universal consensus of American space scientists, has provided a huge boost to the overall Mars exploration schedule -- there's no reason why the ESA couldn't give it another boost in the same way.

Oliver Morton

Bruce, I think those are really good points -- as you know, I'd love a Euro/Canadian Marvel clone -- and it's possible that some people upstairs at ESA and elsewhere in european academia are thinking that way. The guys I was kibbitzing on were self selected for an interest in surface science. That said, there were quite a lot of Mars Express people there who clearly think the complement to a good orbiter is surface science.

I think it's probably best to see it in terms of the general dynamic of european attitudes to US scientific supremacy. While in most areas of big science we hold our own with flagship programmes (eg the antarctic ice cores, CERN, the ESO, ESRF, etc) it's obvious that without a change in political priorities Euro R&D will remain fragmented and less well funded than US R&D across the board. (I think this is a foolish mistake on the EU's side, especially since 110 million europeans with an average level of education as good or better than any on the planet just joined the Union, but there we are). Given this state of affairs, the comforting belief for a european is that though we don't do *everything* the Americans do, we *could* do *anything* the Americans do. An area of science that we can't move into is upsetting, especially one that is intimately linked to something we've just started doing successfully.


Did having Beagle aboard Mars Express result in other instruments not being flown?

Oliver Morton

Good question. I think the answer is no -- I think it just ate up margin at the launch end. Remember that if Beagle had not separated properly, Mars Express would not have had the fuel to enter its ideal orbit, so clearly only a fraction of Beagle's mass, if that, was available for orbital instruments. And throwing something off Mars Express to make room for Beagle would have been very hard, politically.

It's possible Beagle reduced the mass allowance for those that did fly -- at least in the sense of ruling out any last minute growth. Some of the instruments are far lighter than they were back in Mars 96 days. But I don't think any capability was lost, and some was gained (eg the infrared channel on Spicam).

Bruce Moomaw

I can answer that one firmly -- no. From the start, the payload of orbital instruments on Mars Express was planned on the assumption that SOME kind of small lander would be flown, and in fact Beagle was one of two finalists (with the other one being less biologically oriented, although I know little else about it). Of course, if the ESA hadn't wanted from the start to fly a lander, they would have had more weight for orbital science.)


Just been watching the JPL press conference about Opportunity's arrival at Endurance crater and I'm struck again by the lack of ejecta around Endurance especially whne compared to Bonneville and the terrain Spirit is traversing. Endurance is a big hole - where did it all go? Presumably anything that can make a 100m+ hole in rock has to be fairly energetic but I find it hard to believe everything was vapourised or reduced to berries, dust and the odd pebble. The only sizeable rock found on the plain so far appears to be ejecta from yet another quite distant crater. There are a couple of boulders inside Endurance though so surely there should be a few out on the plains.

Charles Schmidt

Thank you helvick for restating my earlier query; indeed - where is the ejecta balnket? Did it just disintegrate and blow away? The impact happened after the salt deposits were laid down, so a body of water can't explain it. Now that I think of it, the blueberry concretions that cover the plains are leftovers from the eroded bedrock matrix, so presumably a large quantity of bedrok material in the area has been eroded, along with the ejecta which is strewn about. At any rate, we must be talking about eons of erosion by wind, turning car sized ejecta blocks into dust. Wat's the current thinking in the science on the missing ejecta?

Bruce Moomaw

The current thinking is that Ray Arvidson's predictions in the December "Journal of Geophysical Research - Planets" were almost totally on target. The dry basalt sand being blown into Meridiani from elsewhere is utterly powderizing the light soft matrix rock in the Etched layer from the top down, leaving behind a top layer consisting of the hard hematite residue from the Etched layer (although Arvidson didn't specifically predict that it would be in the form of concretions) mixed with the inblowing dark basalt sand. The reason there's very little white Etched ejecta from the craters at Meridiani is simply that the erosion from that windblown sand very quickly destroys such loose fragments of Etched rock.

Charles Schmidt

Ah, eureka for the layperson!; so Meridiani is like a big sandbox, with the sand unit on top (a la Charlie Flats), and an underlying layer below of salty rock the consistency of talc, or a vast salt lick. The concretions, which gave a RAT some measure of friction are too heavy to move in a six millibar gale, and resistant to erosion to boot. It seems ironic you would find such an extreme example of etched terrain on a world where erosion, with the exception of seasonal CO2 transitions,is an achingly slow process. Thank you for the model Bruce; it had never been clear to me until now....

Also, the Geofusion digital Mars globe is wonderful; anyone have the full version with complete menu?

Thanks for a wonderful resource here Oliver.


Every time I read your blog, it amazes me what a rembakrale woman you have become. For someone who hates to write, the glimpses that you give all of us into your life are eloquent and inspiring. The hopes and dreams your Dad and I had for you are coming true every day! (And on a less serious note, I am glad that the family desire to travel is so alive in you.)


- I love Coop's eyes, he's so beautiful and what a btrksaocy. Our Amber was a rescue who is still timid after 5 yrs. with us. But very sweet and loving, not at all aggressive or fearful. We see the difference between being shy and actually fearful and feel she would go to the mat! I'll keep my eyes and ears open for potentital adopters for Cooper!

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