To determine how best to explore asteroids in the future, NASA scientists and engineers are taking their experiments underwater in the 15th expedition of NASA Extreme Environment Mission Operations, or NEEMO.

This year's NEEMO expedition, which will include the usual compliment of astronauts and engineers, is slated for October. Since this is the first mission to simulate a trip to an asteroid, there's a lot of work to do before the mission can start.

To prepare, engineers have journeyed to the National Oceanic and Atmospheric Administration's Aquarius Underwater Laboratory near Key Largo, Fla., to work through some of the concepts that will be tested in the fall.

"Even experts don't know what the surface of an asteroid is going to be like," said NEEMO Project Manager Bill Todd. "There may be asteroids that we don't even know about yet that we'll be visiting. So we're figuring out the best way to do that."

NEEMO 15 will investigate three aspects of a mission to an asteroid: how to anchor to the surface; how to move around; and how best to collect data. Unlike the moon or Mars, an asteroid would have little, if any, gravity to hold astronauts or vehicles, so an anchor would be necessary.

NEEMO 15 will evaluate different anchoring methods and how to connect the multiple anchors to form pathways. The aquanauts and engineers will study whether it's more efficient to join the anchors in a straight line or set them up similar to the spokes of a wagon wheel.

Starting Tuesday, May 10, engineers and scientists will begin work to ensure they're prepared for rigorous testing of these concepts in October. During these preliminary tests, they will work on the ocean floor, but will not stay inside the Aquarius. This allows participants to come to the surface and retool equipment if necessary.