Missing the date means having a look at 2016-18 for the first interplanetary mission, says ISRO chief

On Thursday, the Indian Space Research Organisation (ISRO) will initiate a dry run of the Mars Orbital Mission on board the PSLV C25 that is scheduled for lift-off from the spaceport here on November 5.

The dry run will simulate the entire command sequence of the eight-and-a-half hours of the countdown, leading to the lift-off, barely six days before the PSLV rocket actually zooms away into space on what ISRO Chairman K. Radhakrishnan called “the most cost-effective mission” to showcase Indian capability to reach and orbit around the red planet.

“Mars exploration opportunities come once every 26 months … we have put together the best resources available in India as of now because missing the November 5 date would mean having a look at 2016-18 for the country’s first interplanetary mission,” Dr. Radhakrishnan told a group of journalists invited to survey the ISRO’s launch preparedness.

There have been only 51 missions to Mars, predominantly by the U.S., Russia and the European Union consortium, and the success rate has been under 50 per cent. India has made bold an attempt to “engage in meaningful scientific experiments” on a relatively modest budget of about Rs. 450 crore.

The stage has been set at Launchpad 1 in Sriharikota, where all the subsystems of the Mars mission have been fully integrated with the PSLV C25, which will be on its silver jubilee flight after achieving a remarkable success rate of 96 per cent. The mass at lift-off is 1,340 kg.

“The launch rehearsal will simulate the entire procedure of the final eight hours of the countdown, right up to the ignition, after which the system will be shut down,” said P. Kunhikrishnan, the PSLV C 25 Mission Director.

The dry run will demonstrate mission-readiness and on November 1 the Launch Authorisation Board will take the final call on initiating the 56 hours and 30 minutes long countdown, due to start ticking two days later, leading to lift-off at 2.38pm on November 5. Mr. Radhakrishnan said the mission had the scope for course correction at three stages — when the satellite leaves earth and enters Mars’ sphere of influence, a heliocentric middle phase that lasts 300 days and when the satellite is inserted into Martian orbit.

The XL variant of the four-stage PSLV — second and fourth featuring liquid propellants — has been designed to first inject the spacecraft into an elliptical path around the earth in a geocentric phase, then a heliocentric phase, where the flight path is roughly one half an ellipse around the sun.

One of the unique features of the mission arises from the larger ‘Argument of Perigee’ in transferring the orbiter from the earth’s orbit to that of Mars. “Unlike previous missions, this one will have fairly long flight regime of 43 minutes in respect of this,” Mr. Radhakrishnan said.

The spacecraft would intersect the orbit of Mars almost simultaneously. According to scientists, such a rare trajectory — that occurs when the Earth, Mars and the Sun form an angle of 44 degrees — can offer substantial minimum energy opportunities and occur only at intervals of about 780 days, with the next window possible in January 2016 and then in May 2018.

On December 1, the satellite would be injected into trans-Martian orbit and begin a long cruise of 300 days. The ISRO will also depend on antennae-mounted ships Nalanda and Yamuna to track the spacecraft’s trajectory from locations on the South Pacific Ocean, when ground stations would briefly lose signal from the spacecraft for about 10 minutes after the fourth stage propulsion, burnout and separation of the satellite.

The insertion into Martian orbit is expected on September 24, 2014. “Once we inject the satellite into Martian orbit the ISRO will go in for scientific observations that include investigating the Martian atmosphere for traces of methane to determine signs of life,” Mr. Radhakrishnan said.

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