Bengaluru: The Indian Space Research Organisation (ISRO) on Friday afternoon raised the elliptical orbit of Chandrayaan-2 spacecraft around the earth to 277 Km by 89472 km in its fourth orbit-raising operation since the mission was launched on July 22. The mission is poised just one step away from starting its journey toward the moon, beginning August 14.
The orbit was raised from 276 Km by 71,796 Km which was achieved on July 29. Now only one more orbit=raising operation is scheduled on August 6 to achieve an earth orbit of 221 Km by 1,43,585 Km before the spacecraft is powered towards the moon in a translunar insertion manoeuvre on August 14.
As per ISRO’s schedules, Chandrayaan-2 spacecraft will be inserted into the lunar orbit on August 20 before it settles into a 100 Km by 100 Km orbit around the moon. Once that is achieved, the Chandrayaan-2’s lander Vikram, which carries the lunar robotic rover Pragyan, will separate from the orbiter and land on the lunar surface near the lunar South pole between two craters, Manzinus C and Simpelius N, to be only the second mission to do so after the January 2019 Chinese lunar mission, Change-4.
According to ISRO, on Friday’s orbit-raising operations the onboard thrusters were fired for 10 minutes and 46 seconds at 3.27 pm for the spacecraft to achieve its latest orbit.
After fifth earth orbit-raising operations on August 6, the translunar insertion will be performed on August 14 afternoon. When that happens, the Chandrayaan-2 spacecraft (orbiter) will be put in a lunar-bound orbit after it loops around the earth as close to 266 Km altitude before leaving for the moon achieving an orbital distance of 4,13,623 Km. That is when the spacecraft is expected to be captured by the gravitation of the moon, which is at a mean distance of 3,84,400 Km from Earth.
According to ISRO, Chandrayaan-2 is scheduled to orbit around the moon thrice before achieving the 100 Km X 100 Km orbit and then releasing the lander Vikram to land on the lunar surface.
The Rs 978 crore mission involves the orbiter continuing its mission around the moon for two years while the rover Pragyan will explore the lunar surface near its south pole with its capability of moving about for 500 metres over one lunar day (14 earth days). The lander Vikram too can last for one lunar day to carry out its experiments although from its static location on the lunar surface.