Definitely true. And one has to consider the source too; there appears to be little consensus yet about what MSL operations will actually look like.

The current engineering constraints document says this:

"As part of its primary mission, the MSL rover would include the capability for traversing long distances. Currently, the system is being designed for a total actual traverse distance capability of no less than 20 km. For purposes of hardware life and cycle evaluation, it is assumed that this traverse occurs over a terrain with an average rock abundance of 15%, an average slope of 5 degrees, and an average slip rate of 10%. Under these conditions the rover would travel on average about 100-150 m/sol."

But Phil is probably correct that a lot of time will be spent at a particular site before moving on to the next site (as I understand it it takes a fair bit of time for SAM and Chemin to do their things), so the per-sol average traverse is probably not representative.

This is primarily a human factors study, and while it has some interesting tidbits, the notion you seem to be dancing around, that there's some big conspiracy of silence surrounding the MER EDLs, is simply not supported by the evidence.


http://techreports.larc.nasa.gov/ltrs/PDF/...a-2004-5092.pdf -- the "reconstruction" column in tables 3 and 4 seems pretty clear to me. The MER-A RAD firing was 339.4 seconds from entry; the expected 3DOF Monte Carlo range was 317.3-376.2 sec. The MER-B RAD firing was 336.3 seconds from entry; expected 3DOF was 317.1-372.2 seconds.

I'll leave it to Doug to move this discussion to the MER area; it's clearly pretty far off topic here.

If you're going to make sweeping assertions, it might help to exhibit more cognizance of the process involved. The NAIF FTP site (naif.jpl.nasa.gov) is the standard place where JPL trajectory information is released. The file /pub/naif/MER/kernels/spk/spk_a_c_030610-040104_recon.bsp on that site is, according to its label, "a reconstructed cruise trajectory for MER-A, beginning at TECO and ending at atmospheric entry." There is a similar file for MER-B. If Withers is unaware of those files, you might want to make him aware. If there's something inadequate about the information, I'd be curious as to what.

As previously noted, that state information and the EDL engineering telemetry archive, which has been released and is available on the PDS atmospheric node, are all the information I can think of that would be useful for reconstructing the entries of the MERs.

I'm no apologist for JPL, but carping on this topic would appear to be unjustified.

Now, it may be that what Withers is lacking is a detailed description of the MER aeroshell composition, shape, etc. The design details of reentry vehicles are covered under ITAR for what would seem to be legitimate reasons. I haven't tried to find those details, nor do I know what data precision might be required. There's a fair bit of info in http://library-dspace.larc.nasa.gov/dspace...ndle/2002/11213

Have you actually looked at the data that have been released to assess their adequacy? The pre-entry state of the MERs, which is what people have complained about, are on the NAIF FTP site, I believe. All of the raw data appears to be out there to do whatever EDL reconstruction you want; I don't think that the MR doppler tracking is actually useful for the reconstruction, but I believe it was archived with the MOC PDS releases quite a while back.

If Bruce doesn't want to make the investment of time to install and learn OpenOffice, I found that Microsoft's free Word viewer handled this document just fine.

Looks like we released the April-September 2005 MOC data (cycles S05-S10) this morning -- http://www.msss.com/moc_gallery/index.html

http://www.msss.com/mro/ctx/images/2006/04/13/index.html

http://www.msss.com/mro/marci/images/2006/04/13/index.html

and don't forget to follow the link to

http://www.msss.com/mro/marci/images/2006/...tail/index.html

Methane/O2 only has a small advantage over MMH/NTO in specific impulse, and storing cryo propellants is a huge pain, so I don't see how that alone is really harming system performance. The supposed advantage of the methane was always for ISPP at Mars, but if we're not going to Mars than why deal with the complexity?

June is far in the future? OK, I can see how that might be true from your perspective.

http://www.cdscc.nasa.gov/Pages/pg03_trackingtoday.html has a partial daily schedule for Canberra. One could figure out the RA/Dec of NH and decide approximately when a pass could occur. I can't find the frequency allocation anywhere, and a detailed schedule would have to come via the project. If Alan Stern is reading this, he would be a good source.

Try going to the mid-range scheduling page; you can download the DSN schedule, and look for "NHPC" tracking passes.

Doug did all the hard work on this; look back at
http://www.unmannedspaceflight.com/index.p...indpost&p=49703

I'm not sure if there's some overlap with one of these craters, but that'd be instructive. I'd say the MOC image is better than the HiRISE one in Doug's overlap, but MOC probably had better illumination. Clearly from the mapping orbit, HiRISE will outperform MOC.

These look pretty much like MOC images. They're about the same resolution and they show pretty much the same thing -- Mars has a lot of sand dunes and craters

By use of extreme cleverness in implementation, the MOC WA is "virtualized" in that we can take the summed global map and a full-res regional at the same time, subject to CPU cycle constraints. (The hardware maintains a ring buffer of running pixel sums and the CPU subtracts lines from the ring buffer; for full-res it subtracts adjacent lines, for higher summing it subtracts lines farther apart.) After that it's just a question of what data volume you choose to devote to what.

MARCI has no such capability (there was only so much I could jam into the 4K of program memory in the DSP) but we expect to use less summing anyway so it hopefully doesn't matter.

Sorry to disappoint, but the MARCI image is pretty bad, since we were so close to the terminator. You can see Argyre, but the color is fairly muddy and the resolution is only 4-8 km/pixel due to the altitude.

Remember that MARCI's resolution in mapping is only about 1/4 that of the MOC WA.

I've been told this is going to happen this coming Thursday, 4/13.

You can partly blame the NASA press people, who apparently want stuff released on Thursdays and don't want multiple things released on the same day. Or something.

Feel free to list those components; I'm extremely skeptical that any of the X2000 components ended up being megarad hard if they ever saw silicon at all. See http://centauri.larc.nasa.gov/outerplanets/Dscr_X2000.pdf for what these looked like for the first EO. The microcontroller was abandoned; the NVM slice never existed at anything like the hardness levels intended; and if the DC-DC converter was ever developed I've not heard of it. So just what are you referring to?

It's also not necessarily connected to the Mars trilogy. The novella "Green Mars" which is collected in THE MARTIANS is in something of an alternate universe from that of the trilogy, according to KSR.

First off, they don't have any way of telling the rocks from the soils; the APXS and the Mossbauer just see whatever is in front of them. They can, maybe, distinguish the soil from the rock by making a measurement and then brushing the rock and making it again, but that's not foolproof. And second, there is always some ambiguity in these analyses, so don't get the impression that they're so "definitive".

Neither of the MER instruments measures all elemental abundances. The Mossbauer detects iron oxidation states, and the APXS looks primarily for "rock-forming" elements. From the Cornell tech briefing: "The x-ray mode is sensitive to major elements, such as Mg, Al, Si, K, Ca, and Fe, and to minor elements, including Na, P, S, Cl, Ti, Cr, and Mn. The alpha mode is sensitive to lighter elements, particularly C and O." I don't know what the carbon detection thresholds are for alpha mode, but I doubt it's that great. The MER instruments are for geology, not organic chemistry. Note that they can't even detect hydrogen or nitrogen.

Rocks typically have silicon, oxygen, and metals in them. That's what MER was designed to look at. They simply can't see peroxides at all, and they can't see organics to any significant degree.

Sure, you generally hear this from people who are involved in satellite missions.

It may be that there are reasonably-priced satellite missions that can answer environmental questions. The EOS mega-system, however, really muddied the water. It's a classis big-mission/small-mission dichotomy, which in my opinion didn't weigh heavily in favor of big missions.

Yes, I'm aware of those. But to clarify, I wasn't talking about current martian conditions, where clearly full spacesuits are required, I was talking about a hypothetical situation where the pressure had increased 10x to about 100 mbars. If I'm doing the calculations correctly, that's equivalent to an altitude on Earth of about 17 km or 56,000 feet. That's in the gray area of maybe not needing a full pressure suit -- see http://www.nasa.gov/centers/dryden/researc...ER-2/pshis.html

My thinking was clearly prejudiced by this quote from Heinlein's RED PLANET (1949):

"the colonials maintained about two-thirds Earth-normal pressure indoors for comfort and the pressure on Mars is never as much as half of that... Among the colonials only Tibetans and Bolivian Indians will venture outdoors without respirators and even they will wear the snug elastic Mars suits to avoid skin hemorrhages."

Of course on Heinlein's Mars there was enough oxygen in the atmosphere to be used after compression by his respirators. I assumed pure CO2, and I was off on the pressure by 3x, but it made good copy.

I might be prepared to argue that satellites are a very cost-ineffective way to study most aspects of climate change, especially given the extreme difficulty of calibration and the relatively small effects they can see. To date, despite all the hoopla, has EOS delivered on many of its promises?

I'd be happier if the money was spent doing something about the obvious reality of climate change, rather than studying it from orbit. Not that that's likely given the current administration.

Not currently, no. But I feel compelled to mention that in the 24-hour media blitz following the publication of "Observational Evidence for an Active Surface Reservoir of Solid Carbon Dioxide on Mars" by Malin et al, I made a remark to abcnews.com which they reported thusly:

Michael Caplinger of San Diego's Malin Space Science Systems points out that if the warming were to continue at the same rate (that's a big "if"), Mars could become a nearly inhabitable place for people within 5,000 years or so.

"Rather than wearing a spacesuit, you could get away with wearing just an oxygen mask and a thick parka," said Caplinger, who co-authored a study about the observations in this week's issue of Science. "It would be like standing on top of Everest."

--------------------

Well, OK, I said it, and the person from abcnews.com did the best job by far of reporting the story, but it wouldn't be that much like standing on Everest. If the atmospheric pressure went up 10X to, say,
60-90 millibars, that's still about 4-5 times thinner than the summit of Everest (which is at about 320 millibars.)

It's an interesting question if you could avoid skin hemorrhaging at this pressure. Would a spandex bodysuit under your parka be enough?

No, we don't. We have some really crude elemental abundances from orbit and some slightly better ones from the ground. But I don't think elemental abundances tell you much if anything about either clays or peroxides, you need instruments that can look at molecular properties, not just elemental abundances. Phoenix is the first mission that will be able to do that, and then MSL.

I'm sorry, you're right -- and it is confusing

I think it's because the angles are relative to the original image's coordinate system, not the map-projected image's coordinate system. North is obviously straight up in the latter.

Also, if you look at the full ancillary data table, there's this flag that isn't reflected on the website:

OBJECT = COLUMN
NAME = USAGE_NOTE
COLUMN_NUMBER = 40
DATA_TYPE = CHARACTER
START_BYTE = 346
BYTES = 1
FORMAT = "A1"
DESCRIPTION = "Because of the MOC's line-scan nature, depending on the
orientation and sense of rotation of the spacecraft and the optical
inversion properties of the camera system involved, MOC images can
either be normal or flipped left-for-right (independent of whether the
image is north up or south up.) This flag will be 'F' if the image
should be flipped left-to-right, and 'N' if it is already in normal
form."
END_OBJECT = COLUMN

OBJECT = COLUMN
NAME = NORTH_AZIMUTH
COLUMN_NUMBER = 41
DATA_TYPE = ASCII_REAL
START_BYTE = 349
BYTES = 6
FORMAT = "F6.2"
NOT_APPLICABLE_CONSTANT = 0.0
DESCRIPTION = "The angle in degrees clockwise from the reference axis
of the image (a line from the center to the right edge of the image)
to the direction to the north pole of the target body. If the
USAGE_NOTE described previously is 'F', the image should be flipped
prior to applying this angle."
END_OBJECT = COLUMN

After 1/1/1998 they started flying MGS "backwards"; prior to that there would be another flip required. I'm pretty sure that all mapping NAs are "N" though.

Quoted on NASAWatch: "It seems to me that instead of going away quietly with what we were given, we ought to be emboldened to ask for more," said Jill Tarter, SETI Institute.

Now that's a reasonable response. I don't know where the money is coming from either, but darned if the community isn't going to ask for even more