Unless Congress acts this year to restore funding cut by the Bush administration, scientists say, they might lose their last opportunity for the next 200 years to study Pluto - the only planet in the solar system not yet visited by a spacecraft from Earth.
At risk is the $488 million New Horizons mission, now in the design stage at the Johns Hopkins University Applied Physics Laboratory in Laurel and planned for launch in January 2006.
The Bush administration canceled funding for exploration of the outer planets in NASA's proposed 2003 budget, saying the projects had grown too costly. The cuts mean there's no money for the APL to start building its Pluto probe in the fall.
NASA officials said there might be a new round of competition for a Pluto mission, but that would mean a delay of at least two years. If the launch doesn't occur by 2006, scientists warn, they would lose the opportunity to study Pluto's atmosphere.
"Let us hope the last word has not been said on this mission," said Stamatios M. Krimigis, the head of the APL's space department.
It hasn't. Sen. Barbara A. Mikulski, a Maryland Democrat, is chairwoman of the appropriations subcommittee that oversees the National Aeronautics and Space Administration's budget. A longtime booster for the Maryland institutions engaged in space exploration, she resuscitated the APL Pluto mission after it was canceled last year by securing the $30 million needed for this year's design work.
"I am going to fight to restore the funding for Pluto this year so we can make a 2006 launch, and get the best science for the scientists and the best value for the taxpayer," Mikulski said. "Delaying the mission will just increase the cost and decrease the science."
$173 million to Md. groups
From the mission's $488 million price tag, the APL would get $170 million over 20 years to design, build and operate the spacecraft. The Goddard Space Flight Center in Greenbelt would get about $3 million to build and operate its infrared camera.
Icy Pluto would be the last of the nine planets to be visited by a spacecraft from Earth. It is 3 billion miles from Earth - about a 10-year journey, though the APL's mission designers said last week that they had found a way to do it in nine.
They're in a rush because by 2020, scientist believe, Pluto's tenuous atmosphere will have frozen and snowed onto the surface as the planet's eccentric orbit carries it still farther from the sun. It won't warm up enough to study for 200 years.
The Bush administration has proposed increased funding for space science at NASA. But it is reshuffling the cards in a way that could delay - or scuttle - the APL's launch plans.
Under the agency's new administrator, Sean O'Keefe, NASA canceled funding for missions to Pluto and to Europa - a moon of Jupiter believed to have oceans that could harbor life - calling them too costly.
Instead, the space agency is launching a drive to develop nuclear propulsion for spacecraft, which could significantly cut travel time to other planets.
NASA also has created a new class of missions for the outer planets, called New Frontiers. It is modeled after the successful Discovery series of low-cost, competitively bid missions, but cost-capped at $650 million - about twice Discovery's limits.
That's plenty of cash for the APL voyage to Pluto. But even if the APL won a competition for New Frontiers money, said Jay Bergstralh, associate NASA director for solar system exploration, "they probably would not meet a 2006 or 2007 launching date." There's not enough money in NASA's 2003 New Frontiers budget to start construction.
Scientists say Pluto can't wait. "Taking a year out would be suicide for the mission," said S. Alan Stern of the Southwest Research Institute in Boulder, Colo., who heads the APL project. "I think our supporters in the public and in Congress would see it as an attempt to actually kill it."
Editors of the respected sci- ence journal Nature argued lastweek for APL's New Horizons mission as "the best way to reach the last uncharted planet." A craft with nuclear propulsion might get there in five years, they said, but it would take years to develop and test, and would cost more.
The road to Pluto always has been bumpy. The first Pluto mission, designed by NASA's Jet Propulsion Laboratory in California, was scrapped in 2000 after its costs climbed past $1.5 billion.
NASA solicited new, less costly proposals, but budget tightening last spring halted the process.
Mikulski steps in
When Democrats took control of the Senate in June, Mikulski secured the $30 million to restart the competition and keep the Pluto mission alive for another year. In November, NASA chose APL's concept, and design work began.
Krimigis said a detailed design will be completed by the end of the summer.
He said he was puzzled by the administration's argument that plans to visit Pluto had grown too expensive. The APL's winning proposal last year cut the cost to less than half that of the scrapped JPL mission. "NASA knows that, and everyone knows that," he said.
Bergstralh said the APL's Pluto mission nevertheless will have to compete for further funding. It also must fit in with a set of space science goals and priorities for the next 10 years, to be set by planetary scientists in a National Academy of Sciences report due in the spring.
"Supposing that the academy says Pluto is a top priority, then I don't see any reason why [the APL] couldn't propose something like that," Bergstralh said.
Krimigis said the APL's Pluto mission fits the New Frontiers model well and ought to be funded as is.
Stern said the Pluto mission should not have to compete again for funding. "The timing is just too critical to horse around for a year," he said. Besides, a new competition would allow the APL's rivals to capitalize unfairly on its ideas, which are now public.
Stern argues that the APL's Pluto mission should be grandfathered into the New Frontiers program and funded for construction without further delay. "I think there's a number of ways this can be done from a budgeteer's standpoint," he said.
And he's confident that Congress and NASA will find a way to do it. "I don't lose sleep over it," he said. "This mission's very publicly popular. I have a hard time believing this isn't going to happen."