ISRO preps for re-entry experiment of decommissioned satellite; know how it will be done

ISRO is set to undertake what it calls a "challenging experiment" which will involve reentering a decommissioned low Earth-orbiting satellite. The satellite in question is Megha-Tropiques-1 (MT1), which was launched into space on October 12, 2011, as a collaborative project between ISRO and CNES, a French space agency. 

The satellite, which aimed to collect data for tropical weather and climate studies, was originally meant to complete a 3-year-long mission. Nonetheless, it went on to serve ISRO and support climate models for over a decade, according to a readout available on the website of ISRO. 

Now, the space agency aims to perform a controlled re-entry of the 1000 kg satellite on March 7, 2023, under the guidelines issued by the Inter-Agency Space Debris Coordination Committee (UN/IADC) as the object reaches its end of life after years of being in service.

"UN/IADC space debris mitigation guidelines recommend deorbiting a LEO (Low Earth Orbit) object at its end-of-life, preferably through controlled re-entry to a safe impact zone, or by bringing it to an orbit where the orbital lifetime is less than 25 years. It is also recommended to carry out “passivation” of on-board energy sources to minimise the risk of any post-mission accidental break-up," reads the statement. 

What will the re-entry constitute? 

ISRO is now preparing for a fully controlled re-entry into the atmosphere which will impact an abandoned and safe region in the Pacific Ocean. The area lies between 5°S to 14°S latitude and 119°W to 100°W longitude of the ocean. Operations like such involve deorbiting the objects at low altitudes in order to make sure that the impact only takes place at a specified location. 

Most of the times, large satellites are well equipped to experience re-entry as they reach their end of life. However, the MT1 is not necessarily designed for such operations, thus making the exercise difficult to perform. The process for the re-entry has been underway since last year, with 18 orbit maneuvers done since August in order to lower the orbit. After carefully analyzing challenges such as visibility and ground impact, the final step of the entire mission will be executed between 16:30 IST to 19:30 IST on Tuesday.