Closing On Phobos

The European Space Agency's Mars Express probe will fly within 60 miles of the Martian moon Phobos today. It will be the closest of five approaches.

The Martian moons are interesting objects. Both Phobos and it's running mate, Deimos, are small-- both fewer than twenty miles along their longest axis. Astronomers aren't sure whether they are asteroids captured by Mars, or pieces of a larger moon that broke apart. Detailed images of their surfaces might help answer that, but Russia is planning to go one step further with a sample return mission to Phobos in the near future. Soviet operations at Mars were never very successful, so we'll have to see if the Russians can pull off their Phobos project.

Tiny as they are, one or noth Martian moons could play a big role in the human exploration of Mars. Some theorists argue the first human landfall in the Mars system shouldn't be on the planet itself, but on one of the moons. Establishing a base on Phobos, say, would allow the crew to study Mars ckisely over extended periods. A fleet of rovers could traverse Mars faster and more efficiently if controlled in nearky real rime by astronauts at the base, as opposed to rovers driven by pilots on earth with a lag time ranging to several minutes, depending on the distance between the two worlds. Landing on a Martian moon would be much less demanding than landing on the planet, as wel. That final huge step could be taken whenever we were sure we were ready if launched from a base on Deimos or Phobos.