After many delays, NASA's Dawn spacecraft is finally ready to launch tomorrow, on its way to an up-close look at two of the biggest asteroids in the asteroid belt. And about time.
Originally slated for takeoff in July, the so-called "Prius of Space" (no, I don't know how much Toyota paid NASA for that endorsement) was put on hold to focus on the Mars Phoenix lander, which launched Aug. 4. It was pushed back again by weather concerns from a scheduled launch today, and is now sitting fueled on the launchpad, with scientists hoping that the forecast showers don't force yet another delay tomorrow morning.
The mission will be an unusual journey orbiting two successive bodies in turn, asteroids Ceres and Vesta, each very different pieces of space rock.
Vesta seems to be dry, with a range of surface features ranging from lava flows to a deep polar crater. Ceres, by contrast, appears more like the solar system's outer mini-planets, with evidence of water content, perhaps icy poles, and a less evolved surface.
By contrasting both bodies, scientists hope to gain more understanding of how planets evolved both in the inner and outer regions of the solar system. Says mission Principal Investigator Christopher Russell, from
UCLA, in a statement:
The ship itself will be powered by an advanced ion drive mechanism, similar to that tested in the Deep Space 1 mission. Large solar panels on either side of the ship will deploy after launch. The power thus gained will ionize xenon gas fuel, and accelerate the ions, thus propelling the ship forward. It's what's called low thrust – not a lot of power at once, but efficient and long-lasting.
Stay tuned for launch tomorrow at, well, dawn, Eastern time.
NASA Spacecraft Is a 'Go' for Asteroid Belt [NASA press release]
(Image: Inside Dawn's mobile launch service tower at Cape Canaveral. Credit: NASA)
