Over the next few months, NASA will map out a strategy for returning bits of Martian rock and soil to Earth, so scientists can study them for signs of past Red Planet life.

That ambitious goal should drive the space agency's next steps at Mars, according to a report released Tuesday by the Mars Program Planning Group. The report also lays out several ways Mars sample-return can be accomplished over the next decade or two, and NASA is reviewing those options now.

The agency may reveal its chosen path in February, after the White House releases its federal budget request for fiscal year 2014, NASA officials said Tuesday. In the meantime, here's a brief rundown of the scenarios they're looking at.

Multiple launches All the major options proposed by the Mars planning group share three basic components in common: a sampling rover, a Mars Ascent Vehicle (MAV) for blasting the collected rock and soil off the Red Planet surface and a return orbiter, which will snag the samples in space and ferry them to Earth's neighborhood.

In one scenario, these three pieces are all launched separately, with a small "fetch" rover riding along with the MAV. As its name suggests, the fetch rover will carry Red Planet dirt from the sampling rover back to the MAV. [ 7 Biggest Mysteries of Mars ]

This strategy has the advantage of spreading costs and technical challenges across three missions which could each be at least two years apart, since Mars launch windows come about every 26 months according to the planning group report.

Another option is to consolidate into two launches. The sampling rover would ride alone, while another liftoff would carry the MAV, fetch rover and return orbiter.

In this case, the orbiter would likely have to be powered by solar electric propulsion (SEP), to cut down on weight. The amount of liquid propellant needed for a traditionally powered spacecraft would be quite heavy.

A single launch Alternatively, all the pieces needed for Mars sample-return could be lofted in a single shot, the report says.

In this case, the sampling rover would carry an integrated MAV with it, eliminating the need for a fetch rover. Again, the return orbiter would be an SEP craft, which creates thrust by accelerating electrically charged atoms or molecules.

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How NASA will bring home pieces of Mars