New Mars Probe Joins Search for Old One
AP
Nov.14, 2006
DENVER — The hunt is on for the still-silent Mars Global Surveyor, the venerable NASA orbiter that failed to phone home earlier this month.

Now another Mars orbiter is being primed to image the missing-in-action spacecraft.

NASA will attempt this week to use the Mars Reconnaissance Orbiter to spot the errant Mars Global Surveyor (MGS).

If successfully identified and photographed, engineers might be able to better assess what's ailing the troubled probe and perhaps take corrective steps.

Spacecraft engineers remain puzzled as to what occurred onboard the Global Surveyor to curtail its communications with Earth.

MGS was last heard from on Nov. 5, after reporting earlier that it was having problems with a solar panel.

Since then, repeat tries at regaining contact with MGS using the Jet Propulsion Laboratory's Deep Space Network of powerful radio dishes were to no avail.

Engineers here at Lockheed Martin Space Systems — designer and builder of the long-running MGS — have been busily studying the situation.

Navigation, instrument and spacecraft teams are deep in troubleshooting what might have happened to the orbiter.

Without radio contact, the true whereabouts of MGS aren't precisely known.

"Right now, we don't have a great estimate on exactly where MGS is, since it has been out of contact for a while," said Wayne Sidney, the Mars Reconnaissance Orbiter Flight Engineering Team lead for Lockheed Martin Space Systems.

MGS could be in a self-generated safe mode, perhaps making use of its thrusters and having perturbed its orbit about Mars, Sidney told SPACE.com.

By extrapolating from the last known position of MGS, experts hope to deduce where the craft should be as it spins around Mars.

Two-step plan

Tasking the Mars Reconnaissance Orbiter (MRO) which was also designed and built by Lockheed Martin Space Systems, to image MGS won't be easy.

Sidney said that there's a plus-or-minus 45-second widow of error to deal with in catching sight of MGS.

A two-step plan is being implemented, Sidney advised.

The strategy calls for utilizing MRO's High Resolution Imaging Science Experiment (HiRISE) camera on Wednesday, Sidney said, to take a long-exposure photograph that, it is hoped, grabs a glimpse of the MGS.

If HiRISE successfully picks up the fast-moving MGS, then more precise and higher-resolution targeting of the camera system can be done on Friday, Sidney said.

"So it's two steps ... back to back," Sidney noted. "It has been a scramble to try and figure out how to do it. It's going to take a lot of push-ups to get it done this week, but I think everybody involved is actually pretty excited about it. Most of us worked both [the MGS and MRO] programs."

Photographing MGS would help mission controllers learn what direction the spacecraft's mast-mounted, high-gain antenna is pointed. It is used to receive signals from Earth as well as send transmissions to ground controllers.

Knowing the orientation of the spacecraft's solar panels also would be a plus, Sydney said.

Lost cause?

As for calling MGS a lost cause, Sidney stated that there could definitely be a scenario that brings the mute probe back to life. But MGS is the oldest of six spacecraft now active at the Red Planet and has been in service longer than any other spacecraft ever sent to Mars.

Launched in November 1996, the MGS original mission was to examine Mars for a full Martian year, roughly two Earth years. Once that period elapsed, NASA extended the mission repeatedly, most recently on Oct. 1 of this year.

It's important to recognize that MGS was on its third extended mission, Sidney said. And through all the years of scanning Mars, he added, MGS also supported the Mars Reconnaissance Orbiter's lengthy aerobraking at the planet by watching for Martian dust storms that influence Mars' upper atmosphere.

There's a feeling that maybe the well-used MGS felt it was time to sign off.

The 10th anniversary of MGS in space — Nov. 7 — is the same day that MRO cranked up its primary science tasks.

"It really seems like there's some fate involved in this," Sidney said. "MGS knew it was time to retire."