Make Deimos a Space Port

While Philip Christensen would be thrilled with almost any mission to Phobos or Deimos, another long-time space innovator has specific plans for the little moons. Fred Singer, president of the Science & Environmental Policy Project, has argued for the past two years for a human mission to one of the Martian satellites.

"They are neglected," Singer said in a telephone interview. "People have talked only about Mars. To me, these moons are interesting in their own right. That's not to say Mars is not interesting, but I think the moons deserve equal consideration."

But who wants to be the first astronaut to say, "I landed on Phobos!"?

Actually, Singer contends that the best mission to Mars starts at Deimos, the outermost of the two satellites. Take a travelling research vessel stuffed with a half dozen humans and strap it to Deimos for six months, he suggests. Then use the moon -- an odd-shaped object with an average diameter of 8 miles (13 kilometers) that orbits 12,400 miles (20,000 kilometers) from Mars -- as a shield against cosmic rays and solar storms.

Call it a space rock dock.

From the relatively safe perch high above the Red Planet, the crew would send robotic probes to the surface of Mars and control them in real-time (whereas the distance between Earth and Mars creates a long communications delay). And instead of enduring months of red dust on the harsh Martian surface, a small team could make a quick weekend sortie to the surface to do those things only humans can do.

Like making that first footprint in red dust.

But why dock at Deimos, instead of going straight to Mars?

"It's cheaper. It can be done faster, sooner," said Singer, who is also a researcher at George Mason University and whose study of the orbit and origin of Phobos and Deimos dates back to the 1960s. "It's safer, much safer," he continues. "And you can get more information about Mars by exploring it from Deimos than you can by landing on the surface."

For one thing, the scheme would avoid the need to build a costly Mars base, required to shield the crew from deadly radiation. And sidling a large spacecraft up to a low-gravity moon is a lot less costly than setting down on Mars, a maneuver that requires a lot more fuel, adding costly weight to a mission.

And Singer says that from Deimos, scientists could deploy a series of robotic probes to the Martian surface just as easily as they could from Mars. Each probe's destination and mission would be determined by what was learned from previous probes.

Lesson from NEAR

The NEAR spacecraft landing on Asteroid Eros in February illustrates the potential of a mission to Phobos and Deimos, Singer says.

But NEAR was just a robot. Isn't sending humans an incredible undertaking?

"Phobos and Deimos are much easier to get to than Eros, and much easier to land on," Singer said, "so it is a very viable proposition."

A landing would be aided by the fact that the moons are locked into stable orbits and rotations. Eros, on the other hand, was tumbling through space less predictably and made a tricky target.

Meanwhile, the crew could do some serious science on Deimos itself. Singer points out that Phobos and Deimos are similar to Eros in size and appearance. "One wonders if they have any connection," he said.

And now that there is some data on Eros' composition, thanks to NEAR, a comparison could be made. If the objects are similar, it would be strong evidence that Phobos and Deimos are in fact asteroids that were snagged into orbit by Mars' gravitational tug.

Nothing like being out there

Christensen, a geologist by training, says putting humans on Deimos makes sense, and scientists could "learn a lot" about Mars by studying the Red Planet from above.

Chipping away at Deimos wouldn't be a bad thing, either.

"We may never really know the story of these moons, and what they're made of and what their interior is like, until we go and land on them," Christensen said. "There's nothing like being out there with a hammer and a hand lens and doing real geology, being able to pick up the rock and look at it."

Next page: Cool Phobos Facts and Images