Wednesday, January 14, 2004

Mars update, 14 January 04

The Mars rover Spirit is expected to drive off of its platform Wednesday night or early Thursday morning... NASA finally cut the final connection between the rover and the platform, and rotated the rover towards the exit ramp. Analysis of satellite photos as well as those taken by the rover has helped the engineers to plot a course for the rover, and provided NASA with more information about the landing itself:

The spacecraft came to rest only about 250 to 300 meters (270 to 330 yards) southeast of its first impact. Transverse rockets successful slowed horizontal motion seconds before impact, said JPL's Rob Manning, who headed development of the entry, descent and landing system. The spacecraft, encased in airbags, was just 8.5 meters (27.9 feet) off the ground when its bridle was cut for the final freefall to the surface. It first bounced about 8.4 meters (27.6 feet) high, then bounced 27 more times before stopping.

30 feet off of the ground when they cut the cord? *Whew*. They hadn't planned it to be quite so close... that's only 1½ airbag diameters off of the ground. Fortunately engineers had made some last minute changes to the descent to accommodate unexpected weather patterns:

Plunging toward Mars at 920 mph, Spirit's parachute deployed at an altitude of just 4.6 miles - a mile lower than expected - and its braking rockets fired a scant 34 stories or so above the surface in a flawless, but hair-raising descent that engineers are just now coming to fully appreciate.

The parachute deployed later than predicted because of a dust storm on the other side of the planet that affected the density of the atmosphere above Spirit's landing site. Engineers had instructed the lander's computer to take that into account, but they were surprised at the magnitude of the adjustment.

This makes me wonder if the reason we haven't heard from the Beagle is that they didn't make those last-minute adjustments... current thinking is that Beagle is in a crater that is right in the middle of the calculated landing zone, but it might have dug itself a hole if it too had such tight parameters on its landing.

Of course, the biggest question yet to be answered is the still-unresolved issue of whether or not the 3 Yemenis who claim ancestral ownership of Mars (dating back to 3 millenia before NASA even existed) will succeed in their lawsuit against NASA.