The Indian Space Research Organisation (ISRO) made history when it brought down a weather satellite, Megha Tropiques-1, in a controlled re-entry over the Pacific Ocean after its end of life. This was the first time the space agency had attempted such a manoeuvre to clear out space debris, despite the satellite not being built to do so.
About Megha Tropiques-1
Megha Tropiques-1 was a joint mission developed by Indian and French space agencies and was launched in 2011. Its planned mission life was only three years, but it continued providing data on water cycle and energy exchanges in the tropics for nearly a decade. The controlled re-entry of Megha Tropiques-1 involved deorbiting to very low altitudes to ensure impact occurred within a targeted safe zone.
Importance of controlled re-entry
The need for controlled re-entry of satellites has become imperative as several space fairing nations and private entities launch satellites, mostly in low earth orbits. Even the smallest debris can destroy active satellites, and the accumulation of space debris could lead to the Kessler syndrome, where the amount of space debris reaches a point where one collision triggers others.
India’s initiatives in this direction
ISRO has set up a department to monitor space debris and mitigate the risks posed. The space agency follows the guidelines of the United Nations and the Inter-Agency Space Debris Coordination Committee (IADC), which say satellites should be deorbited after mission life either through controlled entry over a safe impact zone or by bringing it down to reduce the orbital lifetime to less than 25 years.
Types of satellites for controlled re-entry
A controlled re-entry is possible only for satellites in the low-earth orbit, at about 1,000 kms over the surface of the earth and not geosynchronous or geo-stationary orbits. Debris from the low earth orbit takes 20 to 30 years to fall to the atmosphere naturally, while it would take generations for those in geosynchronous or geo-stationary orbits to fall. Satellites in higher orbits are usually moved to a graveyard orbit, where they are shot upwards at the end of life. Sometimes, a satellite might escape to deep space.
Uncontrolled re-entry
In an uncontrolled re-entry, the rocket stage simply falls, and its path down is determined by its shape, angle of descent, air currents, and other characteristics. It will also disintegrate as it falls, and the smaller pieces fan out, increasing the potential radius of impact on the ground. Most rocket parts have landed in oceans principally because earth’s surface has more water than land, but many have dropped on land as well.
About the Indian Space Research Organisation
ISRO is the space agency of India and is involved in science, engineering, and technology to harvest the benefits of outer space for India and mankind. It was previously the Indian National Committee for Space Research (INCOSPAR), set up by the Government of India in 1962, as envisioned by Dr. Vikram A Sarabhai. ISRO was formed on August 15, 1969, and superseded INCOSPAR with an expanded role to harness space technology.
ISRO’s aim is the development and application of space technology for various national needs. Its activities are guided by its Chairman, who is also the Secretary of the Department of Space (DOS) and the Chairman of the Space commission. The DOS is directly overseen by the Prime Minister of India. The headquarter of ISRO is located in Bengaluru.
MCQs on The Role and History of the Indian Space Research Organisation (ISRO).
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What was the purpose of the controlled re-entry of Megha Tropiques-1?
A. To clear out space debris.
B. To launch a new satellite.
C. To study water cycle on Earth.
D. To test the satellite’s capabilities.
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What is the Kessler syndrome?
A. A condition where satellites collide with each other.
B. A theory about the creation of space debris.
C. A system to mitigate risks of space debris.
D. A technology to control satellite re-entry.
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What is the role of ISRO in controlling space debris?
A. To monitor space debris and mitigate risks posed.
B. To launch new satellites into space.
C. To move satellites to a graveyard orbit.
D. To escape satellites into deep space.
