India’s bid to put a spacecraft into orbit around Mars continues on track, following successful completion of the planned first major trajectory correction manoeuvre following the Mangalyaan mission’s boost away from Earth orbit.
The Indian Space Research Organisation (ISRO) ordered a 40.5s burn of its 22-Newton thruster during the mid-course correction, with the spacecraft 2.9 million km away from Earth.
A second main correction is planned mid-course during the long helio-centric cruise phase, and the last is scheduled to take place a fortnight before the spacecraft’s arrival near Mars, on 24 September 2014.
The spacecraft escaped Earth’s gravity on 4 December, marking the end of the end of the first phase of the flight and the beginning of a long dormant period for the main, 440-Newton restartable liquid-fuel engine, which will now be fired again only on 24 September 2014. The main engine is of a type that has been used by ISRO on its geosynchronous satellite and Chandrayaan-1 lunar orbiter, although the maximum duration between restarts has so far been just one month, as opposed to the ten-month idle requirement for the Mars mission.
ISRO will now perform in-orbit maintenance of the spacecraft along with a few minor course corrections during the long helio-centric phase. This will be the longest part of the mission and will have to account for the influence of other planets, the Moon and solar radiation pressure on the spacecraft.
Mission success will depend on successfully entering the influence of Martian gravity, for orbital capture. The spacecraft is intended to achieve an elliptical orbit of 366km x 80,000km. Its payload of five instruments, all developed in India, will explore the Red Planet’s surface features, morphology, mineralogy and atmosphere.