It is a joke -- all the failures were purely due to bad design or bad luck, rather than anything about Mars' environment. In the last few months, however, it's started to look as though the Ghoul may have expanded his repertoire to protecting comets.

Comets are now one of the most intensive subjects for planetary scientists, since they represent by far the best-preserved remnants of the original nebular cloud of dust and gas out of which the entire Solar System formed. The new decade started out well for them.

The Stardust probe -- intended to fly by Wild 2 next January 2, collect a tiny sample of dust from its coma, and return it to Earth in 2006 -- continues to work well (except for minor problems with its camera).

And during the optional extension of its original mission, Deep Space 1 provided by far the best look we have had yet at a comet nucleus when it flew by Borrelly in September 2001 -- a success which was regarded as unlikely, since its TV camera had to pinch-hit for its failed star tracker at the same time that it was trying to photograph the comet.

Since then, however, things have gone sharply downhill. First, the CONTOUR probe exploded while firing its rocket motor to leave Earth orbit last August, ruining its plans to make extremely close flybys of at least two and probably three or four different comets to do comparative studies of their structure and composition.

Then the European Space Agency's plans to launch Rosetta -- its very advanced spacecraft to actually rendezvous with a comet, orbit its nucleus for long-term detailed studies, and dispatch a small lander onto the nucleus' surface -- went awry when the last Ariane 5 launch planned before the mission failed disastrously, forcing the mission to miss its January launch window so that extensive work can be done on improving the failure-prone booster.

The problems from this worsened when it started to look as though the missed opportunity might have been the ONLY mission to a comet that Rosetta could carry out without either a years-long delay or major redesign of the spacecraft.

Simultaneously, America's next planned comet mission -- Deep Impact, scheduled for launch next January to fly by Tempel 1, release a secondary craft to crash into its surface at very high speed, and observe the internal layering exposed by the crater beneath the nucleus' sun-baked crust -- was imperiled by cost overruns which threatened to take it over the maximum cost limit of $300 million for all such "Discovery" Solar System missions.

In such a case, NASA was legally bound to cancel it completely only a year before launch, despite the fact that $182 million had already been spent on it -- for allowing any Discovery mission to continue despite breaking its cost cap would set a disastrous precedent for the low-cost mission series.

However, the storm clouds are now tentatively improving on all three fronts. First, Stamatios Krimigis -- director of the space department at Johns Hopkins' Applied Physics Laboratory, which had run CONTOUR -- tells SpaceDaily that APL definitely plans to propose a CONTOUR replacement for the upcoming next selection of one or two Discovery missions in 2004.

This Discovery mission or missions would be launched in the 2008-09 time frame. Krimigis says the mission's details are still rather fuzzy, including which comets it would fly by.

But there are many possible candidates. (For instance, during its extended mission, the original CONTOUR could have flown by d'Arrest in 2008, and then made a second flyby of Encke -- its first planned target - in 2013.)

NASA's independent failure review board has yet to release its report on possible causes for CONTOUR 1's failure, an investigation made much harder by the fact that the spacecraft was out of radio contact with Earth when the engine firing occurred.

Given this, one possible altenative might have been for the Stardust probe's team to instead propose a copy of their own proven probe design to carry out such a multiple comet-flyby mission, and perhaps even try to collect and return samples from more than one comet's dust coma.

However, Stardust principal investigator Donald Brownlee tells SpaceDaily that they have no plans to make such a proposal: "We pretty much have our hands full with Stardust."

Initial speculation by many (including this reporter) was that the most likely cause for the failure might have been a freak flaw in the normally very reliable STAR-30 solid kick motor.

But an Associated Press report on Feb. 13 supposedly quoted the board's leader, NASA chief engineer Theron Bradley Jr., as saying that the board regarded the probable cause as an actual design flaw in the spacecraft which had caused the heat from the firing motor to overheat the tank of hydrazine fuel for CONTOUR's small thrusters and caused it to explode.

Such a verdict would indicate serious flaws in both the design and testing of CONTOUR. This would not only have boded ill for NASA picking APL to fly a replacement -- it might even have endangered the government's approval of APL's "New Horizons" Pluto probe, which hd just been ratified for a 2006 launch after finally and remarkably overcoming initial strong opposition from both NASA headquarters and the White House.

However, Krimigis assured SpaceDaily on Feb. 27 that Bradley had been misquoted in that report, and that he had actually told the reporter that overheating of CONTOUR's hydrazine was still only one of several possible causes still being considered by the board.

Bradley himself has now confirmed this, saying that the final report will probably not be released until late April, due to the need to complete several remaining ground tests. (He says that the error in the AP report was due more to bad editing than to a blunder by the reporter.)

Bradley does say that the final ground tests to overcheck the heating theory -- which, to be accurate, must be run in a vacuum chamber -- are not yet complete. He also mentions the alternative theory -- also not yet fully tested -- that CONTOUR's hydrazine fuel may have begun sloshing when the spin-stabilized craft was accelerating during the STAR motor burn, throwing it into a worsening wobble that could finally have actually torn it apart or set off a hydrazine explosion.

He also points out that, while a flaw in the STAR motor is still a possibility, the motor does have a very good success record -- and so it may very well be that CONTOUR's failure was indeed due to a design flaw in the spacecraft.

APL has already completed its own internal inquiry into likely causes for the failure, but has not yet released it.

Bradley says that the two investigations are likely to agree on a single most likely cause, with several other less likely but possible causes which will also require corrective measures (as was the case with the Mars Observer and Mars Polar Lander failures that also occurred while the spaceraft were out of radio contact).

However, he also says that any criticism of APL by the board will probably not be severe enough to rule out its chances of flying a CONTOUR followup -- and is extremely unlikely to present any threat to its chances of flying New Horizons to Pluto.

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