Message #203883

[Rebecca]

One option the Augustine report suggested would take NASA crews to nearby asteroids and to the moons of Mars. "The bulk of the cost of a Mars mission is getting people to the surface and back again," says Pascal Lee, chairman of the Mars Institute in Moffett Field, California. "If you wait for everything to be ready, it will be decades. Phobos offers us a way to get to the very doorstep of Mars."

Because Phobos is so small, the gravitational field it generates is weak, so much so that once you have established yourself in Martian orbit, landing and take-off from Phobos needs only the smallest of impulses. That means it is cheaper and easier to send spacecraft to distant Phobos than to send them to the surface of our own moon.

From Phobos we could easily explore the surface of Mars using telescopes or remote-controlled rovers before making the final descent to the planet's surface when funding allows (see "The Martian night shift").

But there is more to Phobos than just a convenient stopping-off point - much more. Phobos itself is a giant celestial mystery. "We know what all the solar system bodies that we have explored are, except for Phobos," says Lee. "We really do not know how it formed."