The Dawn spacecraft is currently sitting on the launchpad at Cape Canaveral, where it will wait until September 26th for launch. NASA always chooses these vague, optimistic names for spacecraft. The Mars rovers have names like Spirit and Opportunity or old probes with names like Voyager and Pioneer. Of course there are the dreadfully functional names like Mars Polar Lander. And of course, the odd barbarian always finds his way into the crowd: Viking. But I think that Dawn is named well. Here we have a spacecraft that is actually going to the asteroid belt and examine the asteroid Vesta and the dwarf planet (ala Pluto) Ceres. Of course, Ceres is a smidge smaller than Pluto having a radius of 475 km versus Pluto’s 1153 km. The great thing about asteroids, though, is that their escape velocity is relatively minor. Ceres is only 1.2 km/s, or about 4320 km/h (2685 mph). This is nothing when you consider the escape velocity of Mars is 18,097 km/s (11,247 mph). The bonus here is that spacecraft going to Ceres expend less fuel in their approach (slowing down) and less fuel on take-off.
Dawn will only be orbiting these bodies, not landing on them. Dawn’s mission is to study the formation of these two objects, but I think the longterm effects are much more important. For one, it will give us experience in working with the asteroid belt. Many sci-fi writers have speculated that the asteroid belt will be a great place for space stations and mining operations. If Dawn finds the right things, it could spur further exploration of the asteroid belt. Maybe one day my great grandchildren will visit the space mining museum on 243 Ida (below) and spend the night at the bed and breakfast on its moon Dactyl (the speck on the right).
