Bruce, just because it says so in SCIENCE doesn't mean it's true. You can go back and look at the AO if you can find it, but there was no such "original form". MO did not "grow": the instruments were selected to the mass, power, and volume limits as stated in the AO. VIMS was subsequently deleted because they ran into massive development problems, and the radar altimeter became MOLA for the same reason, but there is no evidence of the kind of growth you suggest in the historical record, only from poorly-informed outsiders and long after the fact. And a lot of the misinformation seems to be sour grapes from unselected instruments, and the VIMS guys talking trash about those of us who made the cut.

According to "The Mars Geoscience/Climatology Orbiter 1990 mission" by Low et al, 1984, an Ames-led climatology study and a JPL-led geoscience study had been combined by the SSEC into a single MGCO mission by January 1984.

While this seems to be the common wisdom, I don't think it's accurate. Mars Observer as flown looked very much like the Mars Geoscience/Climatology Orbiter proposed by the SSEC in the early '80s. The main difference was the addition of two small instruments (MOC and TES) instead of one big one (VIMS). The cost increases through May 1988 are documented well in the GAO report NSAID-88-137FS and say nothing about spacecraft size changes. I see no evidence that there was ever any serious plan to fly multiple spacecraft to address the goals of MGCO. The whole time I worked on it (1988-1993) MO was viewed as a low-cost mission, which in comparison with Galileo and Cassini, it was.

Note that MGCO was originally supposed to cost $250M, not counting its Shuttle launch. The final figure, about $813M, includes the Commercial Titan launch, which was probably at least $150M not including the cost of the OSC TOS upper stage. The GAO report details cost increases for the spacecraft and payload of $163M.

DART was originally proposed to cost 47M dollars, and ended up costing 110M. So it may have been "faster" but it sure as hell wasn't "cheaper."

Not every failure is caused by lack of spending. I'm going with incompetence on this one.

Bruce, I'm not disputing that ITAR is a pain in the ass, but then so is international cooperation in general. Just scheduling telecons with Europe is a huge pain. For that matter, even the East Coast is a pain.

All I'm saying is that the notion that the Cassini problems were caused by ITAR is simply not supported by fact.

Such interfaces are a potential problem, worthy of great scrutiny, regardless of whether they cross international boundaries. Southwood says himself, and this seems clearly the case from the facts in evidence, that this is ESA's error. If they knew the interface was critical, they should have been paying more attention to it. They built the receiver system on Cassini and it was their responsibility to insure it had been commanded into the right mode.

I'd read about this in the official ESA review, had they ever released any such thing.

Was it ITAR that caused them to forget the Doppler effect in their receiver design? I don't think so.
I think they are just using ITAR as a convenient excuse for simple human error.

The spacecraft you mention all used bipropellant systems. LRO uses a monoprop system with significantly less specific impulse, so it needs more fuel for a given delta-v.

I asked the same question you did, but apparently the tankage involved was outside the experience base of previously-designed antislosh baffles. Probably could have been solved, but it was a development risk.

Not the best example you could have come up with: I don't have much trouble imagining a foreign power nuking the US with French arms technology.

That said, I think the Huygens problems had less to do with ITAR than they did with the incompetence of European contractors to ESA.
It may be that ITAR provides a convenient scapegoat for those parties.

Sorry, but I find none of those examples convincing in support of international cooperation. In my opinion, the US could have built all of them at less total mission cost to itself, and that would have supported the US aerospace industry better.

Well, this is probably straying over the line into political discussion, but while the US response to 9/11 may be partially irrational, I don't see how you could say it was paranoid in any sense of that word.

I'm not a big ITAR supporter, and it's clearly gotten way out of control. But the original motivation was to stop satellite and reentry vehicle technology transfer to unfriendly foreign countries. If you think there aren't military applications of space technology, then stop dreaming.

As for the US losing through ITAR: frankly, IMHO international cooperation is overrated. There's some cost savings on paper for NASA, but most of those are lost in the communications hassles entailed at the engineering level -- most having nothing to do with ITAR.

While BAE's roadmap claims they are working on a megarad-hard RAD750, the ones they've delivered are only rated to 100 krad, which is at least 3x too soft for the radiation environment we were working to for EO. Maybe they've moved that bar now.

There have been no dramatic technology breakthroughs. Any claim that a Europa orbiter has been enabled by such is simply marketing hype.

Recall that the PV orbiter and probes/bus were separately launched; you wouldn't want to make one dependent on the other if you could avoid it.

All I can say is that the failure review documents say otherwise. I worked on the project for 5 years, I was there when the spacecraft was lost, and I've read all the documents with a fine-toothed comb. What are your qualifications, exactly?

I'm getting a little tired of these thinly-veiled references to "new physics" you keep tossing in here.

Get real, Bruce, Google searches are free.

http://klabs.org/richcontent/Reports/Failu...erver_12_93.pdf
http://klabs.org/richcontent/Reports/Failu...erver_11_93.pdf

While the most-probable cause in the Coffey report was NTO migration through the check valves and a subsequent explosion in the lines when MMH mixing occurred, they also identified three other potential causes (helium regulator failure, pyro valve failure, and power supply diode failure.) The pyro valve failure is similar to the most-likely cause of the Landsat 6 loss. (The JPL report added two more potential causes involving avionics faults.)

However, as previously noted, in the late 90s material problems in the helium regulator were identified, which lent more credence to a regulator failure as the most-likely cause.

That really wouldn't be a very nice thing to do to the JunoCam vendor, would it?

At any rate, they certainly haven't told us anything about the possibility of deleting JunoCam.

JunoCam does have filters -- it's a tricolor pushframe system that uses TDI to get good SNR given the spin rate. I think the images will be pretty spectacular, especially if we can take more per orbit than the very modest baseline.

Uh-oh, this remark has gotten you in trouble with Cowing again

It seems we have a mole here, unless Cowing is a member.

The latter. From "Propulsion Lessons Learned from the Loss of Mars Observer", Carl S.Guernsey, JPL, 2001:
"This paper presents an overview of the potential failure modes identified by the JPL review board and presents evidence, discovered after the failure reviews were complete, that the loss was very likely due to the use of an incompatible braze material in the flow restriction orifice of the pressure regulator."

Complete paper is online at
http://www.klabs.org/richcontent/Reports/F...y_a01-34322.pdf

Most places on Mars, it's quite easy to just drive around what few rocks there are. A modestly larger wheel might help, but inflatable wheels are hardly necessary. A four-wheel system would have no trouble at all at either MER site.

For a particular rock size and frequency, maybe. For the actual terrain at the MER landing sites, six wheels is serious overkill for rocks and the system is clearly quite challenged on dunes and drifts.

Like I said back on page 3 of this thread -- http://www.unmannedspaceflight.com/index.p...indpost&p=51558 -- they are now saying that the mission total is at least 20 km.

Well, maybe; of course, AI researchers have been saying exactly the same thing since the early '80s. The DARPA Grand Challenge ( http://www.darpa.mil/grandchallenge/ ) does lend some credence to the state of the art, but while software may weigh nothing, the hardware and sensors that drove the Grand Challenge vehicles were orders of magnitude heavier than what we could put on a Mars rover. (Memory and CPU cycles to run that software at usable speeds certainly weighs something!) Also, I think all the GC vehicles had to do was stay on the road, which is a totally different problem than that faced by a Mars rover.

Another point: most unmanned military vehicles, UCAVs for example, are teleoperated, not autonomous. The exceptions are those that fly simple courses with no sensors, like Global Hawk.

I stand by my original statement: we are nowhere close to deploying useful high-level autonomy on Mars.

Have you ever tried to write autonomy software? Regardless of what the typical AI/robotics researcher will claim, reliable high-level autonomy of the sort being discussed is well beyond the state of the art.

You might want to read about the work of Rod Brooks -- http://www.kk.org/outofcontrol/contents.php -- for a discussion of the sort of autonomy we're working on.

I agree too, for suitable definitions of "autonomous", "long", and "several". But for autonomy as JPL has implemented it on MER, and for the range of MER, the autonomy is not frequently used because it doesn't work well enough to do anything but the simplest tasks. Certainly there's no high-level route planning like the sort Phil mentioned. And I'd be surprised if MSL will have or need any more autonomy than MER given the relatively small traverse distance they're talking about.

Now, we're currently working on a much smaller rover with much simpler autonomy that would have longer range (see http://www.amerobotics.ou.edu/research/sr2/ ), but I don't believe JPL is thinking along those lines.