Indian spacecraft poised to launch on journey to Mars
BY STEPHEN CLARK
Posted: November 4, 2013
India's first mission to Mars is scheduled blast off Tuesday aboard a Polar Satellite Launch Vehicle to start a cruise to the red planet, thrusting the Asian power into an elite club of nations capable of interplanetary space travel.
If successful, the mission would put India in rarified company. Only the United States, Russia and the European Space Agency have successfully sent missions to Mars.
"We are ready for an historic launch," said K. Radhakrishnan, chairman of the Indian Space Research Organization, in an interview with India's NDTV television network. "It's a challenging mission, a complex mission, and the ISRO team is geared up for executing this mission."
The mission has a lot of work to do before it gets to Mars, with India tackling fresh challenges in the probe's launch, interplanetary navigation, and the minutes-long communications lag between Earth and the red planet.
Named the Mars Orbiter Mission, the project is set to take off at 0908 GMT (4:08 a.m. EST) from the Satish Dhawan Space Center, India's spaceport on Sriharikota Island about 50 miles north of Chennai.
Liftoff is scheduled for 2:38 p.m. local time.
The 2,954-pound spacecraft, nicknamed Mangalyaan, is mounted on top of India's Polar Satellite Launch Vehicle, an expendable launcher poised for its 25th flight. The PSLV is fitted with six enlarged solid rocket boosters to give the mission an extra boost in a configuration dubbed the PSLV XL.
The four-stage launcher will propel Mangalyaan into an elliptical orbit stretching from 155 miles to 14,600 miles in altitude. Spacecraft separation is scheduled about 44 minutes after liftoff.
The launcher's liquid-fueled fourth stage will coast for 25 minutes before igniting for the mission's final burn, a change from standard PSLV missions required to achieve the correct orbit for the Mars probe to begin its flight to the red planet.
"The PSLV XL vehicle is a proven vehicle, but this is a new mission," Radhakrishnan told NDTV. "We designed a new mission of PSLV XL to meet the injection conditions required for the Mars orbiter spacecraft so that at the minimum energy, we should be able to move from Earth orbit to Mars orbit."
According to a mission overview posted on ISRO's website, engineers modified the rocket's guidance algorithm, augmented the launcher's battery capacity, and deployed two ships with tracking equipment to monitor the flight over the Pacific Ocean.
Once the spacecraft is released after launch, controllers will command the probe to fire its on-board engine six times to boost itself out of Earth orbit and on an interplanetary trajectory toward Mars.
ISRO says the mission's cruise phase should begin by the end of November.
Experts from NASA's Jet Propulsion Laboratory and communications antennas from the Deep Space Network will help track the spacecraft on the way to Mars, assisting India with the precise navigation required for the mission.
If the mission blasts off Tuesday, the probe is scheduled to arrive in orbit at Mars on Sept. 24, 2014.
The journey itself is the primary goal of the mission, according to J.N. Goswami, director of ISRO's Physical Research Laboratory and a top scientist on the Mars Orbiter Mission.
Engineers put together the Mars Orbiter Mission in quick time. Goswami said ISRO approved the mission in August 2011, with all the hardware assembled on the orbiter in less than two years.
Designers based the spacecraft on the Chandrayaan 1 lunar orbiter, which India successfully placed in orbit around the moon in November 2008 and successfully operated until August 2009.
Nearly two-thirds of the orbiter's mass at the time of launch is propellant. Almost all of the mission's 390 liters, or 103 gallons, of liquid fuel will be consumed to accelerate the spacecraft out of Earth orbit and to slow its velocity for capture into orbit around Mars.
Officials want to put the probe in an orbit with a low point 227 miles above the Martian surface and reaching 80,000 kilometers, or nearly 50,000 miles, from the red planet. It will take the spacecraft more than three days to complete one circuit of Mars in such an orbit.
Although the Mars orbiter's main purpose is demonstrating India's ability to accomplish the technical feat of reaching the red planet, it carries five instruments to observe the Martian surface and atmosphere.
One of the sensors is a methane detector, which scientists hope will address long-standing questions of the presence of trace amounts of the gas in the atmosphere.
The European Space Agency's Mars Express orbiter and ground-based telescopes have picked up signals of methane in the Martian atmosphere, but NASA's Curiosity rover turned up a negative result from the surface.
Indian scientists are eager to see how Mangalyaan weighs in on the issue. Methane could come from microbes or active geologic vents.
"One of the important objectives of the scientific part of this mission is to see the presence of methane or otherwise," Radhakrishnan told NDTV. "We have an instrument for that purpose. We also want to see, if methane is present, is it because of geological activity or biological activity?"
Mangalyaan also carries a color imaging camera and an infrared spectrometer to study the mineral composition of the Martian surface, and the mission's atmospheric payloads will yield information on how the red planet's climate was transformed from a wetter world into the barren landscape of today.
Some of the Indian mission's scientific goals match those of NASA's Mars Atmosphere and Volatile Evolution, or MAVEN, mission. MAVEN is set to launch from Cape Canaveral, Fla., on Nov. 18, and it is due to arrive at Mars the same week as Mangalyaan.
"We have had some discussions with their science team, and there are some overlapping objectives" said Bruce Jakosky, MAVEN's principal investigator from the University of Colorado at Boulder's Laboratory for Atmospheric and Space Physics. "At the point where we're both in orbit collecting data, we do plan to collaborate and work together with the data jointly. We just haven't got that far yet in our discussions."
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