LOS ANGELES -- Land a rover on Mars to collect rocks and soil samples that could later be returned to Earth. If that's a budget-buster, then orbit Jupiter's moon Europa, which may have a liquid ocean beneath its frozen surface, or study Uranus' atmosphere.
A team of scientists got together to entertain the question: Where in the solar system should NASA visit next?
The result is a wish list released by the National Research Council that prioritized robotic space exploration between 2013 and 2022. The report did not look at human spaceflight.
"I wish we could do them all," said Cornell University astronomer Steve Squyres, who headed the panel that came up with the list.
For years, scientists have advocated a Mars sample return mission, but it was always too expensive. NASA recently partnered with the European Space Agency to find ways for a joint mission.
The panel recommended considering other options if NASA can't land a Mars rover for $2.5 billion. Alternatives include flying to Europa, but only if it costs less than $4.7 billion. It also suggested missions to Uranus, the Saturn moon Encedalus or Venus. -- AP