The Mars Orbiter Mission (MOM)

for more

The Mars Orbiter Mission (MOM), also called Mangalyaan "Mars-craft"  is a Mars orbiter launched into Earth orbit on 5 November 2013 by the Indian Space Research Organization (ISR) It was successfully inserted into Mars orbit on 24 September 2014, making India the first Asian nation to send a satellite into Mars orbit, and the first nation in the world to do so on its first attempt

The Launch Vehicle - PSLV-C25 will inject the Spacecraft into an Elliptical Parking Orbit with a perigee of 250 km and an apogee of 23,500 km. With six Liquid Engine firing, the spacecraft is gradually maneuvered into a hyperbolic trajectory with which it escapes from the Earth’s Sphere of Influence (SOI) and arrives at the Mars Sphere of Influence. When spacecraft reaches nearest point of Mars (Peri-apsis), it is maneuvered in to an elliptical orbit around Mars by firing the Liquid Engine. The spacecraft then moves around the Mars in an orbit with Peri-apsis of 366 km and Apo-apsis of about 80000 km.  

The mission consists of following three phases:

1. Geo Centric Phase
The spacecraft is injected into an Elliptic Parking Orbit by the launcher. With six main engine burns, the spacecraft is gradually maneuvered into a departure hyperbolic trajectory with which it escapes from the Earth’s Sphere of Influence (SOI) with Earth’s orbital velocity + V boost. The SOI of earth ends at 918347 km from the surface of the earth beyond which the perturbing force on the orbiter is mainly due to the Sun. One primary concern is how to get the spacecraft to Mars, on the least amount of fuel. ISRO uses a method of travel called a Hohmann Transfer Orbit – or a Minimum Energy Transfer Orbit – to send a spacecraft from Earth to Mars with the least amount of fuel possible.

2. Helio Centric Phase
The spacecraft leaves Earth in a direction tangential to Earth’s orbit and encounters Mars tangentially to its orbit. The flight path is roughly one half of an ellipse around sun. Eventually it will intersect the orbit of Mars at the exact moment when Mars is there too. This trajectory becomes possible with certain allowances when the relative position of Earth, Mars and Sun form an angle of approximately 44o. Such an arrangement recur periodically at intervals of about 780 days. Minimum energy opportunities for Earth-Mars occur in November 2013, January 2016, May2018 etc.

3. Martian Phase
The spacecraft arrives at the Mars Sphere of Influence (around 573473 km from the surface of Mars) in a hyperbolic trajectory. At the time the spacecraft reaches the closest approach to Mars (Periapsis), it is captured into planned orbit around mars by imparting ?V retro which is called the Mars Orbit Insertion (MOI) manoeuvre. The Earth-Mars trajectory is shown in the above figure. ISRO plans to launch the Mars Orbiter Mission during the November 2013 window utilizing minimum energy transfer opportunity. 

COST

The low cost of the mission was ascribed by Kopillil Radhakrishnan, the chairman of ISRO, to various factors, including a "modular approach", a small number of ground tests and long (18-20 hour) working days for scientists BBC's Jonathan Amos mentioned lower worker costs, home-grown technologies, simpler design, and significantly less complicated payload than NASA's MAVEN. An opinion piece in The Hindu pointed out that the cost was equivalent to less than a single bus ride for each of India's population of 1.2 billion.

LAUNCH

As originally conceived, ISRO would have launched MOM on its new Geosynchronous Satellite Launch Vehicle (GSLV), but the GSLV has failed twice in two space missions in 2010, ISRO is still sorting out issues with its cryogenic engine, and it was not advisable to wait for the new batch of rockets since that would have delayed the MOM project for at least three years. ISRO had to make a choice between delaying the Mars Orbiter Mission and switching to the less-powerful PSLV. They opted for the latter. There is no way to launch on a direct-to-Mars trajectory with the PSLV as it does not have the power. Instead, ISRO launched it into Earth orbit first and slowly boosted it into an interplanetary trajectory using multiple perigee burns to maximize the Oberth effect.

On 19 October 2013, ISRO chairman K. Radhakrishnan announced that the launch had to be postponed by a week as a result of a delay of a crucial telemetry ship reaching Fiji. The launch was rescheduled for 5 November 2013. ISRO's PSLV-XL placed the satellite in Earth orbit at 09:50 UTC, on 5 November 2013, with a perigee of 264.1 km, an apogee of 23,903.6 km, and inclination of 19.20 degrees, with both the antenna and all three sections of the solar panel arrays deployed. During the first three orbit raising operations, ISRO progressively tested the spacecraft systems.

The orbiter's dry mass is 500 kg (1,100 lb), and it carries 852 kg (1,878 lb) of fuel and oxidiser. Its main engine, which is a derivative of the system used on India's communications satellites, uses the bipropellant combination monomethylhydrazine and dinitrogen tetroxide to achieve the thrust necessary for escape velocity from Earth. It will also be used to slow down the probe for Mars orbit insertion and subsequently, for orbit corrections.