The Indian Space Research Organisation (ISRO) brought down a satellite in a controlled manner after its end of life, for the first time.
Key points
- The weather satellite Megha Tropiques-1 entered the atmosphere after the final two manoeuvres on 7th March and burnt up over the Pacific Ocean.
- Megha Tropiques-1, developed as a joint mission by Indian and French space agencies, was launched aboard a PSLV by the space agency in 2011.
- The planned mission life of the satellite was only three years, but it continued providing data on water cycle and energy exchanges in the tropics for nearly a decade.
- About 125 kg on-board fuel remained unutilised at its end-of-mission that could pose risks for accidental break-up. This left-over fuel was estimated to be sufficient to achieve a fully controlled atmospheric re-entry to impact an uninhabited location in the Pacific Ocean.
- This was the first time that ISRO attempted such a manoeuvre to clear out space debris despite the satellite not being built to do so.
- Usually, satellites are left in their orbit and because of the gravitational pull of the earth, they come down to the atmosphere over years and years.
- When the satellites re-enter the atmosphere, the friction causes it to heat up to extreme high temperatures of thousands of degrees Celsius. Without a heat shield, 99% of a satellite gets burnt up whether in a controlled re-entry or an uncontrolled one.
Kessler syndrome
- Kessler syndrome is a scenario where the amount of space debris reaches a point where they just create more with one collision triggering others.
- This is the reason the space debris are monitored and sometimes satellites have to be moved from their way. Isro carried out 21 such collision course manoeuvres in 2022.
Inter-Agency Space Debris Coordination Committee (IADC)
- ISRO was following the guidelines of UN and the Inter-Agency Space Debris Coordination Committee (IADC) that 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 (the time it would take for a satellite to drop from a particular orbit by itself) to less than 25 years.
- 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.
