NASA launched a probe last Thursday to study Ceres and Vesta, the two largest asteroids in the asteroid belt. Here are the launch videos.

[Time Traveller Newsflash, Friday 28 Sep 07: Uh-oh! I wrote this Thursday night, to be posted on Monday, since I'm off on another biz trip -- and now I see Brad has beat me to the punch with his own Dawn post. Curse you, Denton! Curse you and your nimble brain! *sigh* Well, I cover some different territory, so I'm going to leave this up. It's double the space pleasure, double the interplanetary fun...]

Dawn will reach Vesta in 2011, and Ceres in 2015. According to mission scientists, these are two of the earliest bodies formed in the solar system. Because of Jupiter’s presence, the asteroids’ accretion process stopped very early on—long before the planets’ did. One scientist refers to the asteroid belt as the “boneyard” of the solar system, and their excitement at being able to take a look back in time at how the solar system formed, to examine those old planetary “bones,” is palpable in this 13-minute video, narrated by Leonard Nimoy.

Dawn was cancelled in March due to “cost overruns and technical issues,” according to news reports, but was reinstated after a huge uproar by scientists both in the US and abroad caused NASA officials to reconsider.

The Dawn spacecraft has a 65-foot “wingspan” of solar arrays, which make it resemble a graceful, mechanical butterfly. Once out of Earth’s gravity well, it will use ion propulsion. In space, the featherlight ion-stream acceleration will oh-so-gradually push it faster, and faster, and faster, until it is moving more swiftly than any other spacecraft has ever gone. Here is more on the scientific instruments it will carry.

Vesta is expected to be bone dry; it is the brightest of the asteroids, and the only one visible to the naked eye. Many meteorites that strike the Earth apparently come from Vesta. Ceres is so large that it has now been promoted to dwarf planet status (a designation it shares with demoted Pluto). Here’s an animated gif. And did you know that based on its density and oblate shape, scientists hypothesize that Ceres may contain water under its surface? Possibly even more fresh water than Earth has? Scientists speculate that if so, it may host microscopic life. How cool is that?

On the way to the belt, it will perform a Mars flyby, so I suspect we’ll get some nifty data back from that close encounter, as well.

One of the things I like about asteroids is that they are bite-sized, by astronomical standards. I figure if I had my own spacecraft and a space suit, I could hike around an asteroid in a day or a week or two. What’s more, I could jump and hop like a flying monkey, and maybe even achieve escape velocity with my own feet. Planets are impressive, but jeez, they are monstrous. Suns are even worse. Don’t even get me started on the bigger stuff! It would take lifetimes and armies to map them, to grok them in their fullness. I’ll take an asteroid, to start. They are the hors d’ouevres of the universe. The dim sum. The aperitifs.

I grew up during the Apollo moon mission era, with Asimov and Heinlein and the other masters of SF of the 60s and 70s, and I’ve never gotten over it. I still want my own space ship to toodle around the solar system in. I want to camp out for a while on a stroid, study it in depth, plant my feet on that tiny island of dirt and gaze out at the vast universe. Forget flying cars and household robots. I want to escape the gravity well. I want my own space ship all fueled up and ready to go, and a space suit, and a solar system map. Thus, Feral Sapiens.

Maybe I’ll check again, and see if they’ve got the stuff I need for launch up on eBay yet.