Earl Filskov March 5, 2015
March 6 will mark another first in mankind’s exploration of the Milky Way. Ceres, the largest object in the asteroid belt between Mars and Jupiter will get a visit from Dawn. The Dawn spacecraft mission is a $473 million dollar voyage that is the first to orbit two objects in space.
Dawn of a new era
Launched in September of 2007, Dawn reached the massive asteroid, Vesta in July of 2011. After a 14 month stay in orbit around Vesta, Dawn left for Ceres, the dwarf planet that makes up 25 percent of the total mass of the asteroid belt. At approximately 606 miles by 594 miles Ceres is still small in comparison to our other dwarf planet, Pluto which has 41 times the mass of Ceres. As it has been approaching Ceres since December of 2014, Dawn has been taking images of Ceres for navigational purposes. Dawn has made two course corrections as a result. Since January, Dawn has been sending back high resolutions of Ceres. On February 26, one of these images showed two bright spots apparently coming from the surface of Ceres. Initial speculation is that these are reflections from ice volcanoes.
Mission of firsts
Orbiting two objects is not the only first for Dawn. It is the first craft to orbit a dwarf planet, Ceres as well as the first space probe to use an ion propulsion engine. The propulsion system uses solar-generated electricity to accelerate xenon ions to enormous velocities which produces a gentle but continuous push. Ceres was the first object discovered in the asteroid belt by Father Giuseppe Piazzi in 1801. It was at first classified as a planet but, as more objects were discovered in the same area of space it changed to an asteroid. In 2006 due to its planet like qualities it was reclassified as a dwarf planet along with Pluto and Eris. Scientists believe that Ceres may actually hold more water than the Earth.
It will take time
Although Dawn will be “pulled” into Ceres’ orbit on March 6 it will not be until December that it reaches the 232 mile mapping orbit. Once that it occurs, it will take until about April of 2016 for Dawn’s instruments to get properly calibrated for its mission.