ISRO Mars Orbiter Mission

The ISRO Mars Orbiter Mission which is also known by the informal name MANGALYAAN meaning MARS CRAFT is 1337 kilogram satellite about the size of a small car. The search for Methane in the Martian atmosphere is probably the most significant part of the ISRO Mars Orbiter Mission sometimes called MOM.

ISRO Mars Orbiter Mission-MANGALYAAN

ISRO Mars Orbiter Mission-MANGALYAAN

Martian Methane has been detected by sensors on earth but NASA’s Robotic Rover Curiosity has failed to find the gas during its time on the planet Mars. The Indian Spacecraft will also examine the rate of loss of atmospheric gases to outer space. This could provide insights to the planet’s history billion of years ago.

ISRO Mars Orbiter Mission

The ISRO Mars Orbiter Mission has been left off by India’s very own PSLV C25 Rocket using alternate solid and liquid propulsion in four stages. Once the solid fuel is ignited the resulting thrust cannot be regulated or turned off. But for the liquid fuel, the thrust can be regulated in the engine can be turned off or on. The orbiter is separated from the PSLV C25 rocket and put into an elliptical earth parking orbit. As the orbiter goes away the velocity decreases but as it comes back the velocity increases because of the Earth’s gravitational pull.

PSLV C25 Rocket

PSLV C25 Rocket

The 440N engine is fired for short-duration when orbiter is closer that is when its velocity is high. This raises the orbit, which increases the velocity with the least amount of fuel. After six main engine burns the orbiter gains escape velocity to escape the sphere of influence of earth. Now, the Sun is much more massive than any of the planet and its gravity dominates the solar system. Only very near to the planets does the planetary gravity become stronger than that of the Sun. The region around the planet is referred to as the Sphere Of Influence of that planet and the velocity required to escape the sphere influence is called Escape Velocity.

When Mars is in the right position, the orbiter leaves earth in a direction tangential to the Earth’s orbit. This process of setting the orbiter in a trajectory which will cause it to arrive at mars is called TRANSMARS INJECTION.

Mars Orbiter Elliptical Path

Mars Orbiter Elliptical Path

Now according to Newton’s first law of motion, the orbiter will continue to stay in motion unless acted on by an outside force. Therefore fuel will be used only to correct the trajectory at the orbiter and this process is called Trajectory Correction Maneuver.

The MANGAL YAAN reached mars on September/24th/2014 and inserted into the Martian Orbit. To make this happen, the angle between Earth, Mars and the Sun should be 44 degrees approximately. Such arrangements recur at intervals of about 780 days. If for some reason they failed to launch the probe on November 2013 then the next opportunity will be in January 2016 or May 2018 and so on.

The phenomenon used for detecting the speed at motorists on highways is the same as the one used to estimate the velocity of the orbiter. You see radio waves are continuously sent out to the orbiter for communication with earth.

Well orbiter is moving away from the earth. Each successive radio wave has to travel farther to reach the orbiter before being reflected and redetected back on earth. As each wave has to move farther the gap between each wave i.e., the wavelength increases. This change in wavelength is used to compute the velocity of the orbiter. This phenomenon is popularly known as the Doppler Effect, in honor to the Austrian physicist Christian Doppler.

Doppler Effect

Doppler Effect

 

To reach mars, the orbiter follows a Heliocentric Path meaning orbit around the Sun. The shortest distance between Mars and Earth is 54.6 Million Kilometers. Launching in the shortest possible route to mars and decelerating to mars planet speed would require an extremely large amount of fuel. The route which requires the least amount of fuel is an elliptical orbit of about 680 Million Kilometers which formed a tangent to the mars and the Earth’s orbit around the Sun. This kind of transfer is called the HOHMANN Transfer.

The cost of the MANGALYAAN Mission is 450 Crore Rupees or approximately 72 Million US Dollars. Considering the distance between Earth and Mars is 400 Million Kilometers at the farthest. The cost of MANGAL YAAN expedition is slightly over 11.25 INR per KM or has some may point out cheaper than what auto rickshaws charge in Mumbai(15 INR per KM).

Should India really be exploring Mars when one third of the population of India about 400 million people live below the poverty line?

Now instead of answering this question, I would point out some interesting things,

–>The budget of bollywood movies is 25 to 75crore rupees or more.

–>PM’s foreign trip since 2004 cost around 640 crore rupees.

–>The Sardar Patel statue is estimated to cost 2500 crores and the Diwaali firecrackers market is worth rupees 5000 crores.

In my opinion exploring space is far more important than producing meaningless movies or building lifeless statues.

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