By Leonard David
Senior Space Writer
As the Spirit and Opportunity rovers continue their extended studies of Mars, NASA's Mars program appears headed for change. The shift will be driven by a variety of factors including technical and budget issues, as well as a "rebalancing" of science objectives.
NASA has been engaged since last year in what the agency calls a road-mapping effort to flesh out the details of a Mars master plan that would lead to an expeditionary crew landing on that remote world..
One scenario that has been under active discussion is slipping the mission of the mobile, nuclear-powered Mars Science Laboratory (MSL) from 2009 to 2011. Another possibility was building two MSL rovers to double the data that could be gathered during that mission and reduce program risk.
James Garvin, the chief scientist at NASA headquarters in Washington, said the space agency's science program is undergoing a "rebalancing." He said the status of MSL is still under review, but also said he thinks the prospect for launching two MSL rovers "is long gone."
"Right now, my aim is to ensure one, full-scope Mars Science Laboratory, at the least risky opportunity and best suited to making revolutionary scientific discoveries," Garvin told SPACE.com.
Garvin also said that maintaining progress with the Phoenix Mars lander, which is being readied for a planned 2007 launch, and MSL in either 2009 or 2011 "is essential if the rapid pace of scientific progress is to be continued."
That rapid pace also involves NASA's Mars Reconnaissance Orbiter, recently transported to Cape Canaveral, Fla., where it is being prepped for an August launch.
And in other Mars matters, NASA's Mars Telecommunications Orbiter is targeted for a 2009 launch slot. It is the first piece of communications infrastructure that will provide a link with Earth for all future Mars missions.
Lockheed Martin Space Systems in Denver has entered negotiations with NASA and the Jet Propulsion Laboratory to build the Mars Telecommunications Orbiter for a still-pending contract value, said Joan Underwood, a spokeswoman for the company.
The Mars Telecommunications Orbiter is scheduled to carry a science package still to be selected. It also will evaluate laser optical communications gear designed to speed the flow of data between Mars and Earth. In addition, NASA plans to demonstrate tracking, rendezvous and maneuvering with a football-sized canister that would be ejected from the main spacecraft - a test intended to help the agency hone future robotic Mars return sample procedures.
Newly appointed NASA chief Michael Griffin has accelerated the pace of all road mapping, Garvin said, with emphasis on the Crew Exploration Vehicle and lunar activities in the near term.
"The Mars road mapping has provided useful perspective, coming as it has after several years of communitywide strategic planning for robotic, discovery-responsive exploration of Mars," Garvin said.
The value of this Mars planning will come in the near term, Garvin said, as important decisions are made regarding the path ahead for the robotic Mars Exploration Program in the context of executing President George W. Bush's Moon, Mars and beyond vision for NASA.
"As such, there will necessarily be impacts on the Mars program," Garvin said. Given the criticality of maintaining Mars rover exploration at the surface while implementing a successful Mars Reconnaissance Orbiter, "there may be some consequences," he added, "but the full scope of those won't be fully analyzed until this summer."
The Spirit and Opportunity Mars rovers have yielded far more data than ever anticipated, Garvin said, particularly data that has helped scientists better understand the geochemical and mineralogical workings of Mars. Additionally, the two rovers have set the stage for the follow-on Mars Reconnaissance Orbiter scientific sweeps of the planet, and to target the Mars Science Laboratory in order for that large rover to analyze the best locales for the biogeochemical signatures of life, he said.
"In my view, the results of the Mars Exploration Rovers in the context of what the Mars Reconnaissance Orbiter discovers in its first months of exploration will have an influence on the early mission sequences of the next decade and on the pace of robotic exploration, including the timing of large, complex missions such as Mars Sample Return," Garvin said.
A more definitive timeline for Mars exploration is expected by July or August as NASA lays out its 2007 budget submittals, Garvin said. "So, my message right now is, 'Stay tuned.'"
The longevity of the Spirit and Opportunity rovers has been a surprise to most everybody, said William Farrand, a research scientist with the Space Science Institute here. He is a member of the Mars Exploration Rover science team.
While Spirit and Opportunity clearly have shown the utility of robots to carry out impressive science, Farrand said that people in the field are inherently more flexible than machines. Just flipping over a rock on Mars, for example, is not a task the rovers are capable of performing. "That's something a geologist can do in a second," he added.
Farrand said, however, that serendipitous discoveries have been made by the dual rovers. "Fate plays a role in that, like Opportunity finding an iron meteorite," he said.
While commanding the rovers from Earth to perform work is a tedious, painstaking process, Farrand said the rovers have been hugely successful in delving into the complexities of Mars. "I think we have created a whole new class of experts with this mission," Farrand suggested, "about how to do remote geology with robots."
Story continues at: http://www.space.com/missionlaunches/050520_mars_masterplan.html