Waiting for Dawn

This weekend I spent a bit of time watching the actual sky, especially the horizon-hugging and seemingly huge full Moon (with Jupiter and Antares nearby), and in the early evenings, looking west, Venus and Saturn appearing very close together (but getting too low to see for long before the sky got completely dark). At our Saturday astronomy club meeting, we set up three telescopes, but fast-moving clouds spoiled the view, except for a very brief glimpse of Jupiter with the four Galilean moons sharply visible.

At the meeting we also watched a NASA video on the upcoming Dawn mission to main belt asteroids Vesta and Ceres (Ceres is currently considered a dwarf planet - at 933 km in diameter, it's about 41% the size of Pluto, 27% the size of our Moon). This excellent 13 minute video is narrated by Leonard Nimoy and does great job of explaining the mission with animations, diagrams, and interview clips. Dawn is scheduled to launch on July 7, and is a very ambitious mission. With huge solar panels to generate the needed electrical power, Dawn will use a low-thrust but long-burning ion engine (shown in a still from the video - there are actually three, though they are used one at a time) to make its way to Vesta (September 2011, after a 2009 gravitational assist from Mars), where it will orbit for 7 months before making a second long journey to Ceres (arriving February 2015).

The mission is called Dawn because its investigations of these two proto-planets are expected to shed new light on conditions in the earliest history of the solar system. The mission will also add to our experience in working with smaller bodies in the solar system, which is a key development in our ability to eventually harvest the resources of the solar system for many purposes (though near-Earth asteroids will probably be used before those in the main belt). As usual there is a very helpful PDF press kit (2 MB, 26 pages) available for the launch.