The Dawn spacecraft has left a mark on history. After 3.1 billion miles and more than seven years of expedition in space, the Dawn spacecraft arrived in the orbit of the dwarf planet Ceres on March 6, 2015. Using its unique xenon-ion propulsion system, the spacecraft was caught by Ceres’ gravity at about 7:39 a.m. EST Friday, with a distance of approximately 38,000 miles from the surface.
Dawn is truly remarkable since it is the first mission to orbit a main belt asteroid, as well as two interplanetary bodies – proto-planet Vesta and dwarf planet Ceres. The spacecraft was launched on September 27, 2007, carrying with it three science instruments that will be used to gather data during its mission. On July 2011, it reached its first target, Vesta. Amazing discoveries, incredible photos and measurements were taken and sent back to Earth for analysis and will be used for future reference and study. The spacecraft explored the proto-planet for 14 months before departing for its final destination, Ceres.
Slowly but Surely, Dawn’s “Acceleration with Patience”
The mission would not have been possible without the use of an ion-propulsion system, according to Dawn Chief Engineer Marc Rayman. An ion thruster expels ions; atoms that are electrically charged, to create thrust, instead of the usual chemical propulsion that heats gas or puts the gas under pressure. By giving the xenon gas an electric charge and using high voltage to accelerate the xenon ions through a metal grid, a tiny amount of thrust is generated. The thrust gradually builds up over time, enabling the spacecraft to attain incredible velocities. The engine gently pushes the spacecraft through space and it would take four days for Dawn to accelerate from zero to sixty miles per hour. The ion-propulsion system is ten times more efficient than chemical propulsion systems with the engine making use of only a quarter of a pound of its xenon propellant per day.
Recent photos from Ceres have given scientists more questions rather than really answering any. Some mysterious bright spots, for instance, are quite intriguing. Speculation has aroused as to what these bright spots are and what they could imply. As of now, this issue is yet to be resolved. With Dawn starting to get to know more about Ceres, answers that could lift the cloud from this mystery may be attained. Generally, Dawn is tasked with mapping out the surface of the planet, determining what it is made of, and providing insights to its formation and its implication on the evolution of the early solar system.
With Dawn finally getting a better and sharper view of Ceres, answers and more information about the dwarf planet are highly anticipated in the coming months.
