G V Joshi
As India’s date with Mars – the Red Planet, approaches near and near, the scientists and engineers working at the Indian Space Research Organisation (ISRO) are preparing for the integration of the Polar Satellite Launch Vehicle (PSLV) that will launch the Mars Orbiter Mission.
The spacecraft is slated to be launched by PSLVC25 sometime during October -November. The first stage of PSLV-C25 with strap-ons has already been assembled, with the rocket ready for satellite integration by October 10.
The Mars orbiter mission (MOM) also called as Mangalyaan (rhyming with Chandrayaan launched in 2008) will propel India to the elite club of five nations comprising the U.S.A, Russia, Europe, China and Japan which have launched similar missions.
The spacecraft, with a 1350 kg liftoff mass, will have a single solar array with three panels of 1400 x 1800 mm capable of generating 750 watts of power in the Martian orbit. It will also be equipped with a 36 AH Lithium-ion battery for power storage.
The spacecraft’s dry mass is about 500 kg, and it will carry 850 kg of propellant and oxidizer. The rocket on the spacecraft will use the propellant and oxidiser for orbit insertion and other maneuvers.
The primary objectives of the mission are to demonstrate India’s technological capability to send a satellite to orbit around Mars and conduct meaningful experiments such as looking for signs of life, take pictures of the red planet and study Martian environment.
The MOM will carry on board five scientific instruments or pay loads with an objective to study the Martian surface, atmosphere and sustainability of life.
The five payloads, which will total a mass of about 15 kg, (14.49 kg to be exact) are (1) Lyman Alpha Photometer, weighing 1.5 kg would measure atomic hydrogen in the Martian atmosphere, (2) Methane Sensor for Mars, which will be capable of scanning the entire Martian disc within six minutes, will weigh 3.59 kg. Earlier missions to Mars had detected Methane in the thin Martian atmosphere, but the discovery is yet to be confirmed. Methane is known to be released by some microbes as part of their digestive process.
(3) The Mars Exospheric Neutral Composition Analyser (MENCA) which would study the Martian atmosphere weighs about 4 kg. (4) Thermal Infrared Spectrometer weighing 4 kg will be used to map the surface composition of Mars, and (5) Mars Colour Camera which weighs 1.4 kg,
The spacecraft will have to reach the Red Planet and then orbit around it. It is expected to take 300 days for it to reach the planet. Then the spacecraft will be placed in an elliptical orbit, the nearest point of which from Mars’ surface will be 372 km and the farthest point will be by 80,000 km.
If ISRO failed to launch the mission at the designated launch window (October-November 2013), it will have to wait for another 26 months for the next launch window. The next available launch windows are in 2016 and 2018.
Even after a successful launch, controlling the orbiter is a new challenge. The ISRO’s ground control stations at Baylalu would be facing new problems.
One of them is a 40-minute gap in communication between the ground stations and the spacecraft. In other words, it will take 40-minutes (20 minutes either way) to receive information and relay instructions to the space craft from the ground station. NASA of the US will provide navigation and tracking support services to this mission as and when necessary.
Mars is the fourth planet from the Sun and the second smallest planet in the Solar System. It is named after the Roman god of war, it is often described as the “Red Planet” because of the iron oxide prevalent on its surface, which gives it a reddish appearance. The rotational period and seasonal cycles of Mars are very similar to those of Earth, as is the tilt that produces the seasons.
Mars has two known moons, Phobos and Deimos, which are small and irregularly shaped.
The first successful Mars flyby was in 1965 by Mariner 4. Earlier many astronomers speculated about the presence of liquid water on the planet’s surface.
This was based on observed periodic variations in light and dark patches, particularly in the polar latitudes, which appeared to be seas and continents; long, dark striations were interpreted by some as irrigation channels for liquid water.
By the 19th century, the resolution of telescopes reached a level sufficient for surface features to be identified. In 1877, Italian astronomer Giovanni Schiaparelli produced the first detailed map of Mars, Which contained features he called canali.
These canali were supposedly long straight lines on the surface of Mars to which he gave names of famous rivers on Earth. This term, which means “channels” or “grooves”, was popularly mistranslated in English as “canals”. These straight line features were later explained as optical illusions.
In 2005, radar data revealed the presence of large quantities of water ice at the poles and at midlatitudes. The Mars rover Spirit sampled chemical compounds containing water molecules in March 2007. The Phoenix lander directly sampled water ice in shallow Martian soil on July 31, 2008.
Mars is currently host to five functioning spacecraft: three in orbit – the Mars Odyssey, Mars Express, and Mars Reconnaissance Orbiter – and two on the surface – Mars Exploration Rover Opportunity and the Mars Science Laboratory Curiosity. Defunct spacecraft on the surface include
MER-A Spirit and several other inert landers and rovers such as the Phoenix lander, which completed its mission in 2008.
According to astronomers working at an observatory, based in the New Mexico, USA , the comet , C/2013 A1, heading towards Mars may pass as close as 37,000 km from its surface. It could collide with it in October 2014, possibly ushering in radical environmental changes on the Red Planet.
The astronomical object named C/2013 A1 was first identified as a comet in January 2013 by the Australia-based Siding Spring observatory. The Australian astronomers also confirmed the possibility of the comet’s collision with Mars.
A possible impact would be like an explosion of about 20 billion explosives and possibly leave a crater 500 km wide and two km deep. The impact could raise enough dust and release enough frozen carbon dioxide to radically change Mars’ atmosphere.
The blow could either enhance the greenhouse effect, resulting in a thicker atmosphere, or cause surface temperature on Mars to plummet because the dust would obscure the Sun.
However, according to Shri. M. Annadurai, Director, ISRO Satellite Centre, the scheduled launch of MOM by the ISRO is not likely to be affected by the comet. The implications would be studied in depth as the comet approached Mars and more and more data were available, but then he does not anticipate any problems with the orbiter’s launch.
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