2009 Or 2011 ?, 1 or 2 ? Options

[Guest_BruceMoomaw_*]

Believe it or not, there's still a fight over whether Mariner 5's camera (which JPL wanted to fly) should have been replaced by the dual-frequency experiment (which NASA insisted on substituting). In his book "Flight to Mercury", Bruce Murray bemoans the decision, but some article I saw in the 1980s in "Icarus" still defends it.

[edstrick]

The dual frequency occultation experiment actually turned out to be somewhat "underwhelming". It used longer frequencies than the S-band link to Earth, and because of data recording limitations, only measured the amplitude of the signal and the frequency of the strongest signal being frequency-tracked by the receiver. At the longer frequencies, ionosphere refraction was greater, and one or both channels were refracted enough to cause the radio-occultation equivalent of "mirages": ray-paths got crossed, rendering quantitative analysis of lower altitude data invalid. If they'd been able to record the full signal spectrum, the problem would have been less or maybe quantitatively interpretible.

Radio occultation with receiver on the spacecraft continues to be proposed, as putting a hundred kilowatt continuous wave transmitter on Earth gives a far stronger signal at the spacecraft and higher signal-to-noise than the usual spacecraft-to-Earth link, but since regular radio occultation's nearly free, other than the need for an ultrastable oscillator, it's never made the payload selection.

[Guest_exobioquest_*]

You people get easily distracted don't you?

What are the possible scenarios?

1. Launch 1 MSL in 2009: If all goes as planned so far.
2. Launch 1 MSL in 2011: If it gets bumped up.
3. Launch 2 MSLs in 2011: Why?
4. Launch 1 MSL in 2009, another in 2011 or later: Why not?

[Marslauncher]

You people get easily distracted don't you? 

What are the possible scenarios?

1. Launch 1 MSL in 2009: If all goes as planned so far.
2. Launch 1 MSL in 2011: If it gets bumped up.
3. Launch 2 MSLs in 2011: Why?
4. Launch 1 MSL in 2009, another in 2011 or later: Why not?

Cant wait to hear what Bruce knows....


John Cooke

[Guest_BruceMoomaw_*]

Heh heh heh. Let me take some mercy on you: there will NOT be an MSL in 2011 under the new plan.

Why not? Well, one of the main reasons for the new program design is staring you all right in the face -- you can easily deduce it from what you already know -- but I'M not going to tell you what it is. Heh heh heh...

[RNeuhaus]

In other topic, Bruce has told that the best option is to send first the MTO on 2009, later by 2011 send two MSL since they will capitalize the widest possible bandwidth of communication offered by the Mars Orbiter Telecom MTO with the new optical communication technology. See Bruce's note click here

But as you know that the project of MTO was cancelled? or postponed?, then the most probable best path would be that after MSL 1 in 2009, the next turn would be for MTO along with MSL 2 at the year 2011 or perhaps 2013 depending upon to many factors how is the world is happening in the next years.

Rodolfo

[Guest_exobioquest_*]

To little money going around, that looks like the problem. There no way they can send a second MSL and MTO in 2011 with the budget given (especially with all the manned space flight crap going on). So then #4 is the most likely answer: they are going to launch a second MSL eventually right?

[Rakhir]

You people get easily distracted don't you? 

What are the possible scenarios?

1. Launch 1 MSL in 2009: If all goes as planned so far.
2. Launch 1 MSL in 2011: If it gets bumped up.
3. Launch 2 MSLs in 2011: Why?
4. Launch 1 MSL in 2009, another in 2011 or later: Why not?

You should have a look at this thread.

Rakhir

[Guest_BruceMoomaw_*]

Note that the findings announced today from Mars Express' OMEGA mapper have shown just why it would be a mistake to pick out a landing site for the first sample-return mission without very careful reconnaisssance. We've often been told, after MER-B's findings at Meridiani, that we need look no farther for a good landing site choice for that mission -- but OMEGA's discovery of patches of phyllosilicate clays are an even better one.

We are by no means sure that life could evolve out of organic compounds in a highly acidic water solution such as produced the hydrated sulfates we see at Meridiani and other places; but the more neutral pH water that produced the clay deposits is a very different matter. Also, it seems that the clay deposits are older than most of the sulfate ones -- probably because the latter formed when Mars was colder, so that only water with a substantial amount of sulfuric acid mixed in from local volcanic sources could remain liquid on the surface -- and the earlier, warmer Mars of the clay deposits would have been more favorable as a location for prebiotic evolution simply on the grounds of temperature. I'm willing to bet that a phyllosilicate deposit of this sort will likely be the landing site for the 2009 MSL, as the best possible place to look for fossilized biological organic compounds. (Of course, MRO's far more detailed near-IR mineral maps will be crucial in picking that spot.)

[Guest_exobioquest_*]

Is there a global map by ESA of hydrated clay detected by OMEGA anywhere?, be it incomplete or not. All I can find is a example of Marwth Vallis in the Arabia Terra. If MRO also confirms hydrated clay deposites then would that most likely be were MSL will land at (assuming nothing of greater intrest arises)?, or is Vallias Marineris still a prime target?

[RNeuhaus]

The Terra Meridiani has a mixed materials: Phyllosilicates and Hydrated sulphates. See the report from ESA:

Phyllosilicates were detected by OMEGA mainly in the Arabia Terra, Terra Meridiani, Syrtis Major, Nili Fossae and Mawrth Vallis regions, in the form of dark deposits or eroded outcrops.

Hydrated sulphates, the second major class of hydrated minerals detected by OMEGA, are also minerals of aqueous origin. Unlike phyllosilicates, which form by an alteration of igneous rocks, hydrated sulphates are formed as deposits from salted water; most sulphates need an acid water environment to form. They were spotted in layered deposits in Valles Marineris, extended exposed deposits in Terra Meridiani, and within dark dunes in the northern polar cap.

So the most probably zone with Hydrated sulphates might be closer to Valles Marineris, the Western most of Terra Meridiani. The visiting zone of Oppy must be a Phyllosilicate zone or not since it is located East of Terra Meridiani. isn't it?

Rodolfo

[Guest_exobioquest_*]

Yes, but I was looking for maps that chart the deposits, all I can find is the one they show of Marwth Vallis. MER-B is about 30° south of Marwth Vallis near the western top of Meridani terra, I’m guessing MER-B is not close enough in Meridani (within a 5 km) to such a deposit, but without a map by ESA of that region were in the dark.

[dvandorn]

I'll say the same thing I said in another thread -- the ESA spokesman (I can't rmemeber his name) discussing the phyllosilicates said that the closest observed outcrops to either MER are a good thousand miles away. He was asked how long it might take for one or the other of the MER rovers to get to any phyllosilicate deposits, and he said (paraphrasing, my best recollection of his exact words), "Probably Martian centuries -- the closest is about a thousand miles away."

I remember this specifically because I thought it somewhat odd that a European scientist would reference the distance in miles and not kilometers.

-the other Doug

[Guest_BruceMoomaw_*]

Well, if he was a Brit, he was being nostalgic...

[djellison]

Well - all the roads and speed limits in the UK are still Miles - it's just the rest of Europe that's converted to KPH

Doug