Byline: Alicia Chang
LOS ANGELES AP - For almost half a century, the United States has dominated the exploration of Mars from the first grainy black-and-white pictures of the craggy surface to the more recent discovery of ice.
Now, budget woes are pushing NASA toward a joint exploration venture with Europe. By 2016, the US may unite with the European Space Agency for future Mars trips - a move that would mark a significant shift for NASA.
Details of such a union could come by the end of July.
In May, NASA's space sciences chief Ed Weiler said he believed a partnership was the best avenue to pursue shared science goals "if we can lose a little bit of our ego and nationalism".
A NASA presentation to the Mars science community in March indicated that the two space agencies would likely take turns being the leader.
As Marcello Coradini of the European agency has put it: "In terms of willingness, we all agree that we have to work together. The discussion is not on the 'if,' it's on the 'how' we work together."
The impetus for the unprecedented discussions comes down to money. After delaying the launch of its powerful Mars Science Laboratory to 2011, NASA had to slash its technology spending and scale back its future Mars vision to pay for the $US2.3 billion ($A2.87 billion) next-generation, nuclear-powered rover.
The Europeans, too, have money problems. They lack the cash to send up ExoMars, a new drill-toting rover scheduled to launch in 2016. NASA is trying to figure out how to help Europe land on Mars while sending up its own less capable orbiter during the same launch window.
"That's a difficult partnership because we had an existing mission and they had an existing mission and to merge two existing missions is challenging," said Doug McCuistion, who heads NASA's Mars exploration program. "Frankly, we have backed off quite a bit on our mission requirements. They've backed off somewhat."
Still unresolved is who will pay for the rocket that will blast both out of the Earth's atmosphere and what joint projects to pursue beyond 2016.
While an international collaboration makes financial sense, it is also fraught with risks. The European Space Agency has never successfully landed a spacecraft on Mars, though it has an orbiter circling the planet.
Coradini, ESA coordinator for solar system missions, envisions trade-offs in the partnership.
"We reverse the shared responsibilities. As with any good family, one day it's the husband doing the dishes and another day it's the wife," he said. "If it's always the husband or always the wife, then we're bound for a divorce. …