In September 2007, NASA launched a space probe known as Dawn with a mission to examine two of the three known protoplanets of the asteroid belt, Vesta and Ceres.
Dawn is the first spacecraft to orbit two extra-terrestrial bodies, first spacecraft to visit either Vesta or Ceres and the very first to visit a dwarf planet. After completing a 14 month survey mission in Vesta's orbit, it arrived at Ceres in March 2015. On October 19, 2017, NASA announced the second extension of its Dawn mission. NASA decided to keep the spacecraft in orbit around Ceres until its hydrazine fuel gets exhausted, most probably until the second half of 2018. Later, it will shift in an elliptical orbit. This shall help in providing closer view of the surface than was estimated earlier in the mission. Dawn shall dive closer to the surface i.e. down to around 30 kilometers altitude. This is done to achieve higher resolution and more accurate measurements of the chemistry of Ceres’ surface. It shall help in discovering the origin and evolution of Ceres. The usage of fuel is directly proportional to the closeness of Dawn with Ceres. The mission shall come to an end as soon as hydrazine fuel gets exhausted. It is so because the spacecraft will no longer be able to maintain its control over altitude. It is expected that the data collected at the end shall be used to better understand the concept of “cryovolcanism”. Cryovolcanism is the activity of a cryovolcano or ice volcano which erupts volatiles such as water, ammonia or methane. The scientists have revealed that they had detected the presence of 300 bright spots related to cryovolcanism in the history of the dwarf planet. This establishes that the surface of Ceres is dynamic and it isn’t a dead body.
By: Anuja Arora