The Indian Space Research Organisation stated it efficiently carried out an “extremely challenging” managed re-entry experiment of the decommissioned orbiting Megha-Tropiques-1 (MT-1) satellite tv for pc. “The satellite re-entered the Earth’s atmosphere and would have disintegrated over the Pacific Ocean”, the Bengaluru-headquartered nationwide house company stated on Twitter on Tuesday.
The closing affect area estimated is within the deep Pacific Ocean throughout the anticipated latitude and longitude boundaries, an ISRO assertion stated.
The low Earth satellite tv for pc was launched on October 12, 2011, as a joint satellite tv for pc enterprise of ISRO and the French house company, CNES for tropical climate and local weather research.
Since August 2022, the satellite tv for pc’s perigee was progressively lowered by means of a sequence of 20 manoeuvres, spending about 120kg of gasoline.
Multiple manoeuvres together with the ultimate de-boost technique have been designed after considering a number of constraints, together with visibility of the re-entry hint over floor stations, floor affect throughout the focused zone, and allowable working circumstances of subsystems, particularly the utmost deliverable thrust and the utmost firing period constraint on thrusters.
All manoeuvre plans have been screened to make sure that there could be no submit manoeuvre shut approaches with different house objects, particularly with the crewed house stations like International Space Stations and the Chinese Space Station, ISRO stated.
The closing two de-boost burns have been executed at 11:02 UTC and 12:51 UTC respectively on March 7 by firing 4 11 Newton thrusters on-board the satellite tv for pc for about 20 minutes every, it stated.
The closing perigee was estimated to be lower than 80 km, indicating that the satellite tv for pc would enter the denser layers of the Earth’s ambiance and subsequently bear structural disintegration. The re-entry aero-thermal flux evaluation confirmed that there could be no surviving massive particles fragments.
The whole sequence of occasions was carried out from the Mission Operations Complex in ISTRAC (ISRO Telemetry, Tracking and Command Network), Bengaluru.
An uninhabited space within the Pacific Ocean between 5°S to 14°S latitude and 119°W to 100°W longitude was recognized because the focused re-entry zone for MT1, weighing about 1000 kg, ISRO stated earlier this week.
About 125 kg on-board gasoline remained unutilised at its end-of-mission that might pose dangers for unintended break-up, an ISRO assertion had famous.
This left-over gasoline was estimated to be adequate to realize a totally managed atmospheric re-entry to affect the uninhabited location within the Pacific Ocean, ISRO had stated.
Controlled re-entries contain de-orbiting to very low altitudes to make sure affect happens inside a focused secure zone.
Usually, massive satellites/ rocket our bodies, that are prone to survive aero-thermal fragmentation upon re-entry, are made to bear managed re-entry to restrict floor casualty danger.
However, all such satellites are particularly designed to bear managed re-entry at end-of-life (EOL).
“MT-1 was not designed for EOL operations through controlled re-entry which made the entire exercise extremely challenging,” ISRO stated.
Furthermore, the on-board constraints of the aged satellite tv for pc, the place a number of methods had misplaced redundancy and confirmed degraded efficiency, and sustaining sub-systems underneath harsher environmental circumstances at a lot decrease than initially designed orbital altitude added to the operational complexities, it stated.
Innovative workarounds have been carried out by the operations crew based mostly on the research, deliberations, and exchanges among the many mission, operations, flight dynamics, aerodynamics, propulsion, controls, navigation, thermal, and different sub-system design groups throughout the ISRO centres, who labored in synergy to surmount these challenges, it stated.
Although the mission life of the satellite tv for pc initially was three years, it continued to offer useful information providers for greater than a decade supporting regional and international local weather fashions until 2021, ISRO stated.
UN/IADC (Inter-Agency Space Debris Coordination Committee) house particles mitigation tips suggest de-orbiting a LEO (Low Earth Orbit) object at its EOL, ideally by means of managed re-entry to a secure affect zone, or by bringing it to an orbit the place the orbital lifetime is lower than 25 years, in line with ISRO.
It can also be advisable to hold out “passivation’ of on-board energy sources to minimise the risk of any post-mission accidental break-up, ISRO said.
The orbital lifetime of MT-1 would have been more than 100 years in its 20 deg inclined operational orbit of 867 km altitude, it said.
“As a accountable house company dedicated to secure and sustainable operations in outer house, ISRO proactively takes efforts for higher compliance with the UN/IADC house particles mitigation tips on post-mission disposal of LEO objects”, the ISRO statement said.
