Nearing its mission closure of 11 years of the expedition, the Dawn spacecraft of NASA has reached its final orbit getting the sharpest views around Ceres, a dwarf planet and the king in the entire asteroid belt.
On reaching an elliptical orbit, Dawn turned off its ion engine on June 6th, getting as close as 35 km (22 miles) of Ceres in its every 27-hour loop. At the farthest point, Dawn was taken by the orbit to about 4,000 km (2,500 miles). It is presently flying almost ten times closer than ever to Ceres. This allows the spacecraft’s scientific instruments to get better surface compositions and features. The orbit has been designed to let Dawn get lower over the Occator Crater that has instigated the attention of space enthusiasts and scientists on its brighter salt deposits.
The spacecraft has been running low on its hydrazine maneuvering propellant where Dawn, can hardly depend on its spinning momentum wheels to aid pointing, but engineers have elongated the probe’s fuel lifeline to get an extra of two years of scientific observations on Ceres.
Previously studied exclusively via telescopes, the spacecraft Dawn is first to be at Ceres. Arriving early in 2015 after orbiting Vesta, the giant asteroid in 2011 and 2012, Dawn came close to Ceres during early 2015, making this all robotic mission the first to revolve around two objects of the solar system apart from the moon and the Earth.
Last year NASA had approved a final extension on the mission, and a new trajectory was worked on by planners at the Jet Propulsion Laboratory to facilitate Dawn reach as close as possible to Ceres. Dawn was guided into the lowest orbit of Ceres in the past few months through a series of ion engine burns by using xenon, electrically burned to generate thrusts of lower levels for weeks at times repeatedly.
Ceres happens to be the biggest of objects in the entire asteroid belt, in a zone between Mars and Jupiter orbits. Entirely of about 950 km (590 miles) across, Ceres is around 40 percent Pluto’s size, but one-quarter of its total mass is in the asteroid belt.
Dawn was made to pause in the intermediate orbit taking detailed snaps and infrared spectra of the southern hemisphere of Ceres during summers, as it is when the sun shines brighter. This improved lighting along with higher spectral coverage, scientists get the better idea to compare its south with the north.