Wednesday, December 30, 2009
As of today, New Horizons is now more than halfway to Pluto...in terms of distance, that is. The amount of time since launch (1440 days) is still well below the number of days we still have to wait before it flies by (1928). To see exactly where the probe is now, see this page. Here are two images from there:
New Horizons is exciting in a Voyager-style discovery sort of sense, as we haven't launched a probe out to such a distance since 1977, but Dawn is in my opinion a more exciting mission, as it will not only be arriving at both Vesta and Ceres before New Horizons makes its way to Pluto (July 2011 and February 2015), but these two destinations are completely new and also close enough to Earth that they may be good locations for human colonization. Actually, 24 Themis might be even better (also here en français). Given the recent discovery of the creation of water on the Moon and the fact that there is no reason the same process shouldn't occur on asteroids as well, the more we know about these locations the better.
Dawn's location can be seen here. At the moment it's still circling the Sun at a position quite close to Mars, but is just about ready to break away and make its way towards Vesta. Since the approach to Vesta is so slow the mission overview also notes that optical navigation will begin 3 months before arrival, with more and more accurate images leading to a more precise approach, and hopefully around then (one year from now) we will see some published images as well.