Bangalore: ISRO On March 7, a decommissioned low earth orbiting satellite – Megha-Tropix-1 (MT1) – is gearing up for a challenging test of controlled re-entry. MT1 was launched on October 12, 2011 as a joint satellite initiative by ISRO and the French space agency, CNES, for tropical weather and climate research.
According to the space agency, an uninhabited area of the Pacific Ocean between 5°S to 14°S latitude and 119°W to 100°W longitude has been identified as MT1’s target reentry zone. And, since August 2022, 18 orbital maneuvers have been performed to progressively lower the satellite’s orbit.
The final two D-boost burns are expected to take place between 4:30 pm and 7:30 pm on March 7 and 4:30 pm on March 7, and ISRO said that aero-thermal simulations show that a large chunk of the satellite is undergoing aerothermal heating. Not likely to survive. Re-entry time.
“Although the mission life span was originally up to three years, the satellite has been providing valuable data services for over a decade supporting regional and global climate models till 2021,” ISRO said.
The UN Inter-Agency Space Debris Coordination Committee (IADC) Space Debris Mitigation Guidelines recommend de-orbiting a low Earth orbit (LEO) object at the end of its life, preferably by controlled re-entry into a safe impact zone, or bringing it into orbit. Where the orbital lifetime is less than 25 years. “Passivation” of on-board power sources is also recommended to reduce the risk of post-mission accidental break-up.
“The orbital lifetime of MT1, weighing about 1,000 kg, will see it spend more than 100 years in an operational orbit inclined at 20 degrees at an altitude of 867 km. At the end of the mission, about 125 kg of on-board fuel remains unused which could pose a risk of accidental separation. This remaining fuel is tranquil It was estimated to be sufficient to achieve a fully controlled atmospheric re-entry to affect an uninhabited location in the ocean,” ISRO said.
It added that controlled re-entries involve de-orbiting at very low altitudes to ensure impact is seen within a targeted safe zone and, typically, large satellite/rocket bodies that are likely to survive aero-thermal fragmentation after re-entry. Controlled re-entry to limit the risk of ground accidents.
“However, all such satellites are specifically designed for controlled re-entry at end-of-life. Not designed for MT1 EOL Operation through controlled re-entry which made the whole exercise very challenging. “Furthermore, the on-board limitations of older satellites, where several systems have lost redundancy and have shown degraded performance, and maintaining sub-systems at much lower environmental conditions than originally planned orbital altitudes added to the operational complexity,” ISRO said.
Innovative solutions were implemented by operations teams based on studies, discussions, and exchanges among mission, operations, flight dynamics, aerodynamics, propulsion, control, navigation, thermal, and other sub-system design teams across ISRO centers, who worked to address these challenges. together to do.
Stating that 18 orbital maneuvers were performed to gradually reduce the orbit, ISRO said: “Amid orbiting, aero-breaking studies were also conducted at different solar panel orientations to gain better insight into the physical mechanism of atmospheric drag. Orbital decay of satellites.”
The final de-boost strategy is designed considering a number of constraints, including visibility of the re-entry trace at the ground station, ground effects within the target area, and allowable operating conditions of the subsystems, particularly maximum deliverable thrust and maximum thrust. Firing duration of thrusters.
According to the space agency, an uninhabited area of the Pacific Ocean between 5°S to 14°S latitude and 119°W to 100°W longitude has been identified as MT1’s target reentry zone. And, since August 2022, 18 orbital maneuvers have been performed to progressively lower the satellite’s orbit.
The final two D-boost burns are expected to take place between 4:30 pm and 7:30 pm on March 7 and 4:30 pm on March 7, and ISRO said that aero-thermal simulations show that a large chunk of the satellite is undergoing aerothermal heating. Not likely to survive. Re-entry time.
“Although the mission life span was originally up to three years, the satellite has been providing valuable data services for over a decade supporting regional and global climate models till 2021,” ISRO said.
The UN Inter-Agency Space Debris Coordination Committee (IADC) Space Debris Mitigation Guidelines recommend de-orbiting a low Earth orbit (LEO) object at the end of its life, preferably by controlled re-entry into a safe impact zone, or bringing it into orbit. Where the orbital lifetime is less than 25 years. “Passivation” of on-board power sources is also recommended to reduce the risk of post-mission accidental break-up.
“The orbital lifetime of MT1, weighing about 1,000 kg, will see it spend more than 100 years in an operational orbit inclined at 20 degrees at an altitude of 867 km. At the end of the mission, about 125 kg of on-board fuel remains unused which could pose a risk of accidental separation. This remaining fuel is tranquil It was estimated to be sufficient to achieve a fully controlled atmospheric re-entry to affect an uninhabited location in the ocean,” ISRO said.
It added that controlled re-entries involve de-orbiting at very low altitudes to ensure impact is seen within a targeted safe zone and, typically, large satellite/rocket bodies that are likely to survive aero-thermal fragmentation after re-entry. Controlled re-entry to limit the risk of ground accidents.
“However, all such satellites are specifically designed for controlled re-entry at end-of-life. Not designed for MT1 EOL Operation through controlled re-entry which made the whole exercise very challenging. “Furthermore, the on-board limitations of older satellites, where several systems have lost redundancy and have shown degraded performance, and maintaining sub-systems at much lower environmental conditions than originally planned orbital altitudes added to the operational complexity,” ISRO said.
Innovative solutions were implemented by operations teams based on studies, discussions, and exchanges among mission, operations, flight dynamics, aerodynamics, propulsion, control, navigation, thermal, and other sub-system design teams across ISRO centers, who worked to address these challenges. together to do.
Stating that 18 orbital maneuvers were performed to gradually reduce the orbit, ISRO said: “Amid orbiting, aero-breaking studies were also conducted at different solar panel orientations to gain better insight into the physical mechanism of atmospheric drag. Orbital decay of satellites.”
The final de-boost strategy is designed considering a number of constraints, including visibility of the re-entry trace at the ground station, ground effects within the target area, and allowable operating conditions of the subsystems, particularly maximum deliverable thrust and maximum thrust. Firing duration of thrusters.
