With an array stuck I think MGS would immediately leave the nadir-fixed orientation, since the array would be unable to track the sun, as it would need to do. Unfortunately I don't know too much about the safing mode that is entered with a stuck SA gimbal; for example, what pointing of the HGA is commanded in that mode.
(Most of what I know is left over from Mars Observer, and the HGA never got deployed on that mission.)

Unfortunately this is in the normal mapping attitude. In nearly all safe mode orientations it won't apply, and in some safe modes, it uses thruster control instead of reaction wheel control and will consume fuel even faster. But we are still talking fairly low consumption rates; it's not like it's spinning wildly about looking for Earth. Its normal response to faults is to get the solar arrays pointed at the sun and then spin slowly about the sun line, awaiting commands. There are a few complicating factors: first, the whole problem started with a stuck solar array (one of two); second, the spacecraft goes into solar and Earth eclipse on every orbit; and third, the low-gain transmitter antennas are both up on the articulated HGA electronics box, so there are some orientations of the HGA that could block one or the other of the LGTs from view from Earth. The low-gain receivers are down on the body of the spacecraft and do not articulate.

Compiled from public sources: see http://pds-geosciences.wustl.edu/missions/...og/insthost.txt and http://klabs.org/richcontent/Reports/Failu...erver_11_93.pdf

So which did you want, good outreach or a HiBlog type effort?

Seriously, if somebody was blogging instead of working on recovering the spacecraft, I'd fire their ass.

You're doing just about as good a job with the radiation log as I could; I hope they don't yank it off the web. I am not empowered to discuss spacecraft operations publicly; inquiries have to be directed to JPL.

MGS is either power-positive right now, in which case we will get it back eventually, or it's not, in which case it's dead and gone. Not much else to explain.

MARCI and CTX images at http://www.msss.com/mro/ctx/images/2006/10/16/index.html

I was in this guy's position, more or less, about 15 years ago on Mars Observer. Let's say that it's the dilemma of people with inside information as to how much to say in a public forum. That's why I am always very careful to only talk about stuff that can be found in public sources, even if it seems innocuous. It's too easy to get into trouble with the PI or JPL otherwise, and for what?

That said, my prediction, on the basis of no inside information whatsoever, is that the HiRISE people will discuss some science results that the MOC team knew about years ago but nobody else understood or appreciated :-)

You guys can give all this amateur image processing a rest any old time now. I think we all acknowledge that the HiRISE images are so remarkably fabulous that we might just as well turn MGS off right now and fire the MOC team.

What did they have to do with HESSI? (which was nearly trashed by an inhouse test accident at JPL.)

Did anybody read the EIS? In my quick skim, they really didn't make this case as strongly as I thought they would, focusing mostly on the latitude restrictions that would come with solar. Frankly, if I read the EIS in isolation I might well conclude that they hadn't really justified needing the RTG.

I don't know if such information was ever presented for the station, but certainly there are cost estimates in THE MARS PROJECT ( http://www.amazon.com/Mars-Project-Wernher...n/dp/0252062272 ) in which he said the project "would cost no more than a minor military expedition extending over a limited theatre of war." You might say his estimates were overly optimistic, but he presented his reasoning so I would advise you to read the book and form your own opinion.

Old news, though. http://www.msss.com/mars_images/moc/2003/07/08/

Well, I don't recall having read anything like that, so I can't really speak to your impression. Certainly Odyssey is a lot like MCO, and MRO is clearly a direct evolution from MCO. And there is some commonality between MGS and MCO, since Lockheed-Martin in Denver did the structure and propulsion for both. But as far as the avionics goes, very little commonality. See, for example, http://www2.jpl.nasa.gov/files//misc/m96pkt.pdf -- "To minimize costs, most of the spacecraft’s electronics and science instruments are spare units left over from the Mars Observer mission. The spacecraft design also incorporates new hardware — the radio transmitters, solid state recorders, propulsion system and composite material bus structure."

There is always a tendency to oversell heritage and commonality, but the engineering reality is often far different.

It certainly had a lot of effect on FBC, but were the losses caused by FBC? The MCO loss could have been prevented with the right 5 minutes of extra engineering time. Anyone who tells you there is a simple, direct relationship between mission cost and the probability of success is oversimplifying the problem -- how much extra money would you have had to spend for that 5 extra right minutes to happen? If spending more money was a guarantee, we wouldn't see big mistakes on costly programs like Galileo and HST. Published accounts by the people at LMA involved in MS98 (see http://klabs.org/richcontent/MAPLDCon02/pr..._a/a0_euler.pdf and http://brain.cs.uiuc.edu/integration/AAS01_MCO_MPL_final.pdf ) suggest that fairly modest increases in mission cost (on order of 30%) would have been enough. I think the pendulum on cost versus risk has swung way too far in the direction of cost.

Every electronics box in the MGS spacecraft, with the single exception of the solid-state recorder, is a Mars Observer spare.

If we're going to have an argument, perhaps you could state your qualifications. I worked on one of the instrument teams for each of Mars Observer, MGS, MCO, MPL, Odyssey, Phoenix, and MRO.

There's almost no commonality between MGS and MCO/Odyssey; the former was built with Mars Observer spares.

Since there was no commonality between MGS and MCO, this could hardly have been a cause. I don't think we need to debate, again, why MCO failed; that story is fairly well documented and doesn't have much to do with better-faster-cheaper in my opinion.

This idea surfaces every few months. Unfortunately, unless you are flying very similar missions and payloads and builidng a fair number of spacecraft (at least 5 or 10, at a guess) there are few economies of scale the way spacecraft are typically built. (You have to get into dozens or hundreds before they really kick in; Motorola did some interesting things for the Iridium constellation, for example.) Design commonaliity is usually at the box or subsystem level; there is little savings to be had for spacecraft structure, since structure is fairly easy to redesign. For example, there's a lot of commonality between Mars Odyssey, Stardust, and Genesis, even though they are pretty different missions.

And you'll forgive me for being opposed to give APL and the NH team a monopoly on building hardware to explore the outer solar system, much as I'm sure they would like that.

It would appear, though the text does not state this in any way, that the high-res image is merely the MOC image colorized by and overlain on HRSC stereo-derived topography. Else, why would they credit MSSS?

The smallest current version of the Surveyor solid motor, the Star-37, has a mass of about 800 kg. It's about a meter in diameter.
See http://www.spaceandtech.com/spacedata/moto...r37_specs.shtml

JunoCam is a wide-field-of-view instrument, so a satellite approach would have to be pretty close to yield anything better than what we have already. And I suspect that Juno will be deliberately kept away from the satellites to keep the orbit perturbations to a minimum. But it's a long time until this mission flies, so I wouldn't count anything out yet.

And on the topic of gravity measurements, I ran across an abstract, "Gravity Inversion Considerations for Radio Doppler Data from the JUNO Jupiter Polar Orbiter" ( http://www.aas.org/publications/baas/v36n4/dps2004/158.htm ) that describes some possibilities, though I haven't seen the full paper.

On MGS, the main issue as I recall was loss of attitude reference during aerobraking, so that the spacecraft couldn't tell which direction the aeroflux would be from and needed the radome to avoid heating. I'd be surprised if the MRO situation were any different, given the amount of thermal analysis and design we had to do for this case for CTX.

On the first one, fair enough. On the second, what's your source? On MGS it was definitely for aerobraking, because the MGS HGA was just the spare one from Mars Observer, and the MO one didn't have a radome. See http://mars.jpl.nasa.gov/mgs/movpics/atlo_...al/arrival.html -- "The radome over the high gain antenna is to protect it from the aerobraking environment."

No, MGS is at about 2 PM and MRO is at about 3 PM.

I'm just curious, do you sell to non-US customers without an export license? I would think that some of this stuff would be classified as controlled by ITAR.

I seem to remember reading around the time that Quaoar was named that a general naming source for KBOs was going to be non-western creation myths, but I can't find that reference at the moment (Mike Brown's web pages have all been updated since then.)

Frankly, if these names reference the IAU debacle, then they are a little too whimsical for my taste.

I can't speak for the HiRISE team, but I believe there's only one day's worth of off-nadir imaging allocated pre-conjunction, so if they don't hit it then, and they don't go right over it, it's not going to happen.

I don't think it's giving much away to say that the MER-B site is in the CTX target database.

And I think you're overstating the incremental value of HiRISE imaging over the MOC CPROTO for traverse planning, but I guess we'll see.

I don't have any information to offer you, but I'll note that MSSS has absolutely nothing to do with THEMIS data release; ASU operates that instrument, we just built the visible subsystem and the flight software.

I'd also be surprised to see the pre-conjunction images handled in the same manner as normal mapping, as this is an engineering checkout period and we will be tweaking things, the processing pipelines aren't fully debugged, etc.

As to the rapid release of HiRISE data: I'll believe it when I see it.

This is the so-called "radome" that protects the antenna from heating during aerobraking. MGS had one too. It's made out of aluminized kapton.