Mars researchers are bracing for “six minutes from hell” tonight when the first of twin rovers slams into the top of the planet’s atmosphere at 12,000 mph and begins its perilous descent to the surface. The fate of the $410 million Spirit rover, which has traveled 300 million miles in seven months to reach this point, hangs on those 360 seconds. Spirit will arrive at 9:35 p.m. MST as it attempts to become the fourth spacecraft to land successfully on Mars. The condition of the British-built Beagle 2, which hasn’t uttered a peep since its scheduled arrival on Christmas Eve, is still unknown.

When the first of two NASA rovers arrives on Mars next Saturday, a Denver-built orbiter will be the key link in a new system to relay vital landing data back to Earth. Mars Global Surveyor will pass 250 miles overhead on Jan. 3 when the the first of the golf cart-sized rovers, Spirit, streaks to its landing site. Spirit is scheduled to arrive at Gusev Crater, a giant impact basin that may once have held a lake, at 9:35 p.m. MST. About a minute before it bounces to the surface, Spirit will begin transmitting detailed information about its status to Global Surveyor. About two hours later, those vital signs will be beamed back to Earth.

Mars researchers are keeping a watchful eye on a large dust storm that could – if it grows into a raging global event that shrouds the whole planet – complicate efforts to land the first of two NASA rovers less than three weeks from now. “Usually they appear and die out in a few days to a week, or they expand into global storms. We don’t know what’s going to happen with this one,” said Bruce Jakosky, a University of Colorado geologist who served on the site selection committee for NASA’s $820 million Mars Exploration Rover mission. The dust storm was spotted late last week and now covers a large region of the planet’s northern hemisphere, Jakosky said Sunday during a Mars exploration workshop for reporters.

As one of two Colorado-based researchers on the science team for NASA’s upcoming Mars rover mission, geologist William Farrand Farrand will be among the first to view the pictures sent back from the ruddy, dust-cloaked surface. “As much as they need food or water, people need to explore, to see what’s over the next hill or what’s on the next planet,” Farrand said from his office at the Space Science Institute in Boulder.