ESA finished its probably most ambitious mission focused on deep space exploration. Yesterday, after mild descent, Rosetta space probe touched the rocky surface of Comet 67P/Churyumov–Gerasimenko.
Yesterday all employees at ESA’s control center in Darmstadt, Germany, had rather nervous day. Engineers and specialists from ESA were waiting to receive final confirmation of positive result of planned descent and collision of Rosetta spacecraft with Comet 67P/Churyumov–Gerasimenko. It was precisely planned and prepared end of lasting for last twelve years mission of ESA duo: Rosetta space probe and descent module called Philae. Probe landed at Deir el-Medina pit wide for 130 m designated by ESA due the appearing inside it 1 meter sized clods which are considered as main material forming the comet. Data gathered during last meters of descent were crucial due the lack of second chance for approach or transmission and luckily were sent and received on Earth.
End of the mission was being prepared since July 27, 2016, when ESA decided to switch off Electrical Support System Processor Unit (ESS) responsible for supporting communication with Philae. On August, ESA gradually decreased altitude of orbit of Rosetta to finish it with last maneuver performed at 20:50 GMT on Thursday, 29 September. Rosetta performed then last burn of its thruster to reduce speed and enter collision course with comet. Before planned touch down, specialists from Darmstadt took care to prepare probe for last mission. All instruments, which were not useful during descent, were switched off; Rosetta was set in position with gain antenna faced to Earth and with solar arrays remaining in the sunlight. They also prepared Rosetta for switching off after landing. Final approach was conducted with speed of 0.9 m/s just before touchdown; signal was lost at 10:39 GMT. Last picture was taken by OSIRIS camera on altitude of 20 m above surface of the comet.
It is worth to remind whole story of mission which begun on March 2, 2004 when Rosetta with Philae installed was launched on atop of Ariane 5 rocket from Guiana Space Center. During long journey lasting for decade Rosetta and Philae reached Comet 67P. On November 12, 2014 Philae was deployed and reached surface of the comet. Unfortunately it tumble after landing and finally landed on one of its sides under large rock. This caused problems with charging batteries by solar panels and Philae lost communication with Rosetta. In 2016, on September 2, ESA announced that Rosetta finally took clear and detailed picture of 67P with Philae - it was ultimate confirmation of assumed reason for anomaly with lander and the first detailed guide for the point where Philae landed. During its mission Rosetta and Philae collected data which allowed to allowed to state the following facts about Comet 67P; Nucleus of the comet is not magnetic but whole comet is generating magnetic field. Comet itself is highly porous and its north part is smoother but its south part is rather rocky and rough. Probe also found water on the surface which composition based on high level of deuterium. Philae also confirmed presence of organic participles on Comet 67P what partially confirms theory, that life on Earth begun with collision with comet which brought to our planet water and some kind of organic compounds.