Nov. 13, 2006  -- Ten years ago -- 10 years last week, in fact -- a little ship named Mars Global Surveyor was launched from Florida, designed to spend two years in Martian orbit.

It hasn't been heard from in a week now, and the engineers at the Jet Propulsion Lab in California are finally getting worried.

Something on the ship apparently went awry when it sent a signal that it was having trouble orienting one of its solar panels to face the sun. A corrective command was radioed back.

The response was two days of silence, and then a carrier signal suggesting the ship had gone into "safe" mode -- essentially shutting down non-essential systems until its earthling masters could figure out what was wrong and send further orders. It's roughly analogous to your computer crashing, then giving one of those messages that says, "This system has recovered from a serious error. …"

That was Sunday a week ago, though, and for a ship that has endured the rigors of deep space for so long, time may finally be running out.

NASA's Deep Space Network has been sending signals to the orbiter every two hours. So far, silence.

"The spacecraft has many redundant systems that should help us get it back into a stable operation, but first we need to re-establish communications," said project manager Tom Thorpe in a NASA statement.

MGS was overshadowed in 1997 by the Mars Pathfinder lander -- you probably remember it, with its toaster-sized Sojourner rover -- that landed on the Martian surface, wandered among the rocks, took beautiful color panoramas, and captured the American imagination.

Global Surveyor quietly did more substantial things. It sent back detailed mapping images of almost all the Martian surface, shooting pictures of what, to many scientists, looked like gullies in the sides of craters. NASA theorized that relatively recently, geologically speaking, there may have been liquid water spurting from underground reservoirs into the Martian sand.

Three other orbiters and two other rovers have arrived safely from Earth since Mars Global Surveyor. They have more advanced cameras and more powerful onboard computers. NASA fully expected to end the MGS mission around 1999; instead, it's had to keep allocating extra money to staff this project that nobody expected would last this long.

JPL has "lost" probes before, and recovered them completely. But it takes time, and skill, and steely nerves.

After the Pathfinder lander went silent in October 1997, Brian Muirhead, the project manager, gave ABC News an interview.

"It's as if a good friend is gone," he said. "I didn't get to say a proper goodbye."