Press Trust of India
Chennai, 12 November: A day after suffering a glitch during the fourth orbit raising operation on its Mars Orbiter Mission, ISRO today successfully completed the supplementary manoeuvre this morning, raising the spacecraft’s apogee (farthest distance from Earth) to over 1,18,000 km.
"The fourth supplementary orbit raising manoeuvre of Mars Orbiter spacecraft started at 5.03 a.m. (IST) with a Burn Time of 303.8 seconds and it has been successfully completed. The observed change in apogee is from 78,276 km to 1,18,642 km,” ISRO said.
The supplementary manoeuvre, which was completed by 5.10 a.m, added a velocity of 124.9 m/s to the spacecraft, it said.
After suffering a glitch during the fourth orbit raising operation yesterday, ISRO planned for a supplementary manoeuvre at 5 a.m. to achieve the targeted apogee of one lakh km.
The fifth of the five orbit raising operation to raise the spacecraft’s apogee of over 1,92,000 km is scheduled for 16 November.
During the fourth orbit raising operations yesterday, the 440 Newton liquid engine stopped, while both primary and redundant coils were energised together, however the thrust level augmentation logic, as expected, came in and the operation continued using the attitude control thrusters and the spacecraft was “normal” and “100 per cent safe,” according to ISRO.
Following the glitch, the apogee was raised only to 78,276 km against the target of about one lakh km.
During the first three orbit-raising operations, the prime and redundant chains of gyros, accelerometers, 22 Newton attitude control thrusters, attitude and orbit control electronics as well as the associated logics for their fault detection isolation and reconfiguration were exercised successfully.
After successfully completing these operations, the mission is expected to take on the “crucial event” of the trans-Mars injection around 12:42 a.m. on 1 December.
ISRO’s PSLV C 25 successfully injected the 1,350-kg Mangalyaan Orbiter (Mars craft) into orbit around Earth some 44 minutes after a textbook launch at 2:38 p.m. from Satish Dhawan Space Centre at Sriharikota on Tuesday last, marking the successful completion of the first stage of the Rs 450-crore mission.