Mars Orbiter Mission now halfway to moon

The mission successfully completes fifth orbit-raising manoeuvre

The Indian Space Research Organisation (Isro) on Saturday completed the fifth orbit-raising move of its Mars Orbiter Mission (MOM) spacecraft. The spacecraft has covered half the distance to the moon.

The mission was launched through spacecraft PSLVC25 on November 5.

Isro officials said the fifth-orbit raising manoeuvre started at 1:27 am, with a burn time of 243 seconds and an incremental velocity of 101.55 m/s. In the process, the 440N liquid engine raised the apogee from 118,642 km to 192,000 km.

The next step would be trans-Mars injection, in the early hours of December 1, after which the spacecraft would travel 1,000,000 km a day for 300 days. The December 1 operation would impart a specific velocity to the spacecraft so in September the spacecraft reaches close to Mars (500 km, +/-50).

“The crux of the success of the operation on December 1 is we should be able to estimate precisely the velocity, and the time we need to impart the velocity to the spacecraft so it takes that position. In that, the computation of the spacecraft navigation is important: How it passes from the sphere of influence of the Earth and enters a heliocentric orbit,” said Chairman K Radhakrishnan.

On September 24, Isro would have to reduce the velocity. “If we are able to reduce the velocity precisely at that point, we will get the orbit and, finally, the instruments will be operated.”