WASHINGTON (CNN) -- Still smarting over the loss of two spacecraft last year, NASA scientists are ready to unveil a much more cautious campaign to deploy robots on the surface of Mars over the next 15 years, CNN has learned.
The space agency's Mars brain trust on Thursday will announce a 2005 mission in which an orbiter will map the Martian surface with an eagle-eyed camera. In 2007, a "major lander and rover" mission will follow.
Beyond that, sources say, the agency will remain vague about Mars missions over the next fifteen years. This stands in contrast to the specific agenda outlined in the heady days of the "faster, better, cheaper" approach to space exploration.
Before the Mars Climate Orbiter and Polar Lander were lost in, respectively, October and December of last year, NASA had hoped to send a lander to the surface of the Red Planet in 2003. The craft would have been capable of gathering - and then launching back to earth -- samples of Martian soil and rock.
Agency officials have not ruled out such a mission, but are not prepared to announce any plans for one. Sources say NASA would like to be more flexible in its response to any scientific surprises -- or engineering failures.
The '05 orbiter mission being unveiled on Thursday will feature a camera that would map the Martian surface with unprecedented 20-centimeter resolution -- meaning it will be able to record features as small as a license plate.
The satellite currently orbiting Mars -- the Global Surveyor -- is capable of 3-meter resolution, and even at that level of clarity, astounded scientists this past June with tantalizing hints that liquid water may exist beneath the surface of the frigid, arid planet.
The lander-rover combination to be launched in 2007 will touch down with the aid of rocket thrusters -- not the airbag scheme used on the successful Pathfinder mission in July of 1997. A landing site has yet to be chosen.
Agency officials say the Mars program will be spending more money on technology so future landers can be equipped with a "smarter" descent capability -- such as a radar that could steer a craft clear of menacing terrain. NASA would prefer to avoid using airbags because they are extremely heavy -- thus limiting the number of scientific instruments a lander can tote.
The Mars Polar Lander did not have any obstacle avoidance capability as it made its approach to the surface of Mars even though a rock as high as a coffee-table would have been a show-stopper. As it turns out, that may have been a moot issue, as engineers believe a sensor on the Polar Lander mistook landing gear deployment for the jolt of touchdown, silencing the descent engines prematurely.
NASA officials say future Mars missions will receive Pathfinder-sized budgets of between $200 million and $300 million -- or roughly the entire budget for the Polar Lander and Climate Orbiter missions combined.
Launch windows for missions to Mars open up every 26 months -- when the planet is in its closest proximity to Earth.
In August, NASA announced that in 2003 it will send to Mars a pair of updated versions of the Sojourner rover that wheeled its way into the public fancy during the Pathfinder mission in '97.
Next April, in the only mission that survived the bloodletting in the wake of the 1999 Mars "mean season," the Surveyor 2001 should begin a trek to Martian orbit that will, if all goes well, end this time next year. The orbiter will be equipped with three sensors designed to find proof of ancient Martian water flows.
Surveyor 2001 was not killed because the failure of its sister ship -- the Mars Climate Orbiter -- was attributed to a navigational blunder, not a hardware flaw.