[LINK] "Asteroids Offer Stepping-Stones to Mars, Expert Says"

[rfmcdonald]

National Geographic notes the argument that near-Earth asteroids might be more suitable targets for near-term spaceflight than a more distant Mars.

NASA sees Mars as its "ultimate human destination" and is making plans for a flyby past, or even a landing on, the red planet sometime after 2030. In preparation for that trip, the space agency plans to retrieve a truck-size asteroid, or a boulder off a bigger one, for astronauts to explore. That project, known as the Asteroid Redirect Mission and scheduled for around 2025, would provide an interim goal for the large Space Launch System (SLS) rockets that NASA hopes will someday carry humans to Mars.

"There is a better way," writes MIT planetary scientist Richard Binzel Wednesday in the journal Nature. "Thousands of shipping-container-sized and larger asteroids pass almost as close as the Moon each year."

Instead of retrieving an asteroid, Binzel suggests mapping the nearly ten million uncharted space rocks more than 33 feet (10 meters) wide that orbit between Earth and Mars. He estimates that ground-based telescopes have located only about 0.1 percent of them so far.

Once they were all located, the space agency could plot a series of missions that would allow astronauts to visit some of them. The trips would be for progressively longer periods, which would build experience and confidence to take on the years-long voyage to Mars itself. (Related: "Proposed Mars Missions Challenge NASA Health Standards, Panel Warns.")

To pull off the asteroid mapping, Binzel says, the space agency, which now has a $17.8-billion budget, would need to launch a roughly $800-million space telescope dedicated to detecting space rocks.

As an added bonus, he points out, the mapping effort would help us detect any asteroids that might be headed for Earth, like the 66-foot-wide (20-meter-wide) one that slammed into central Russia in 2013.