Until this week, the recommendations of the A. Thomas Young Committee on the form of the future U.S. Mars program were also to be released, but reportedly now delayed.

In the lead up to these reports SpaceDaily recently interviewed Dr. Daniel J. McCleese, Chief Scientist of the Mars Exploration Directorate at the Jet Propulsion Laboratory.

While McCleese is understandably vague on a lot of the details, not so much because he is forbidden to mention them as because they genuinely haven't been settled yet, he has provided a lot of intriguing information on the new form which the program is likely to take.

First: Dr. McCleese confirms that the touchdown ground-contact switch problem, will indeed be called the "leading candidate" as the cause of MPL's failure.

First revealed by SpaceDaily, this problem centers around the switches in MPL's landing legs which were supposed to detect their flexing on touching the Martian surface and signal the craft to shut off its landing rocket engines.

Apparently, when the craft first ejects its heat shield at 7.5 km altitude and swings its folded legs down into landing position, they "bounce" slightly -- causing the switches to set a bit in the craft's computer memory which records that landing has already occurred.

The craft doesn't start monitoring the status of this bit until it is only 40 meters above the surface -- but when it does, it immediately shuts off the engines, crashing the remaining distance onto the surface.

This problem has now been repeatedly duplicated in ground tests -- but the "most probable" cause of failure is not the only possible cause.

As with the disappearance of Mars Observer shortly before reaching the planet in 1993, the report is likely to list several other possible causes of failure -- all of which will have to be corrected on the next lander.

But, even if the two 1998 Mars Surveyors had not failed, major changes would have been necessary in the program.

Meanwhile, the first attempt to return Martian surface samples to Earth -- which was originally supposed to cost about $400 million -- has now mushroomed to almost a billion dollars.

This mission would involve, first, the launch by a Delta 3 of a new enlarged Mars lander in 2003, which would carry an "Athena" rover that would travel as much as several kilometers from the lander, analyzing the surface with a set of instruments, and using a tiny core drill to pick up and save rock and soil samples from particularly interesting sites.

The rover would then return to the lander -- which would meanwhile have gathered more samples itself, using an Italian drill capable of penetrating half a meter into the soil -- and the resulting 500 grams of samples would then be launched on a two-stage solid rocket into a low Martian orbit.

In 2005, a second similar lander would be launched -- and so would a largely French-built orbiter which would carry out automatic rendezvous with the two tiny orbiting sample containers and then return to Earth with them in 2008.

McCleese states that, while this overall mission design will be retained, the launch of the first sample-return lander will definitely be delayed until the next launch window in 2005, and perhaps until 2007 -- although he says that strong attempts will be made to avoid longer delays.

The problem is one both of the mission's higher cost -- which must now be stretched out over a longer period -- and genuine uncertainty that the sophisticated new technologies needed for this mission will be ready by then.