ISRO preps for re-entry experiment of decommissioned satellite on March 7
Bengaluru ( PTI): The Indian Space Research Organisation (ISRO) is preparing for a challenging experiment of controlled re-entry of a decommissioned low earth orbit satellite, Megha-Tropiques-1 (MT1), into the earth's atmosphere on March 7.
MT1 was launched on October 12, 2011, as a joint satellite venture of ISRO and French space agency CNES for tropical weather and climate studies.
Although the mission life of the satellite was originally three years, the satellite continued to provide valuable data services for more than a decade supporting regional and global climate models till 2021, the Bengaluru-headquartered space agency noted in a statement on Sunday.
UN/IADC (Inter-Agency Space Debris Coordination Committee) space debris mitigation guidelines recommend deorbiting a LEO (Low Earth Orbit) object at its end-of-life (EOL), 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, according to ISRO.
It is also recommended to carry out "passivation" of on-board energy sources to minimise the risk of any post-mission accidental break-up.
The orbital lifetime of MT1, weighing about 1,000 kilograms, would have been more than 100 years in its 20 degree inclined operational orbit of 867 km altitude. About 125 kg on-board fuel remained unutilised at its end-of-mission that could pose risks for accidental break-up.
This leftover fuel was estimated to be sufficient to achieve a fully-controlled atmospheric re-entry to impact an uninhabited location in the Pacific Ocean.
Controlled re-entries involve deorbiting to very low altitudes to ensure impact occurs within a targeted safe zone.
Usually, large satellites/rocket bodies which are likely to survive aero-thermal fragmentation upon re-entry are made to undergo controlled re-entry to limit ground casualty risk. However, all such satellites are specifically designed to undergo controlled re-entry at EOL.
MT1 was not designed for EOL operations through controlled re-entry which made the entire exercise extremely challenging.
Furthermore, the on-board constraints of the aged satellite, where several systems had lost redundancy and showed degraded performance, and maintaining subsystems under harsher environmental conditions at much lower than originally designed orbital altitude added to the operational complexities.
Innovative workarounds were implemented by the operations team based on the study, deliberations, and exchanges among the mission, operations, flight dynamics, aerodynamics, propulsion, controls, navigation, thermal, and other subsystem design teams across the ISRO centres, which worked in synergy to surmount these challenges.
An uninhabited area in the Pacific Ocean between 5 degrees south to 14 degrees south latitude and 119 degrees west to 100 degrees west longitude was identified as the targeted re-entry zone for MT1.
Since August 2022, 18 orbit manoeuvres were performed to progressively lower the orbit. In between the de-orbiting, aero-braking studies at different solar panel orientations were also carried out to gain better insights into the physical process of atmospheric drag affecting the orbital decay of the satellite.
The final de-boost strategy has been designed after taking into consideration several constraints, including visibility of the re-entry trace over ground stations, ground impact within the targeted zone, and allowable operating conditions of subsystems, especially the maximum deliverable thrust and the maximum firing duration of the thrusters.
The final two de-boost burns followed by the ground impact are expected to take place between 16.30 hours to 19.30 hours on March 7.
Simulations show that no large fragments of the satellites are likely to survive the aerothermal heating during the re-entry.
"As a responsible space agency committed to safe and sustainable operations in outer space, ISRO proactively takes efforts for better compliance with the UN/IADC space debris mitigation guidelines on post-mission disposal of LEO objects," the statement said.
The re-entry experiment of MT1 has been undertaken as a part of the ongoing efforts as this satellite with sufficient leftover fuel presented a unique opportunity to test the relevant methodologies and understand the associated operational nuances of post mission disposal by direct re-entry into the Earth's atmosphere, it was stated.
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Maharashtra, Haryana Elections doctored, wasn't free and fair: Cong says after CWC meeting
Belagavi: The Congress party held a press conference on Thursday following the conclusion of its Congress Working Committee (CWC) meeting in Belagavi. This significant meeting marked the centenary of the party's only session presided over by Mahatma Gandhi in Belgaum in 1924.
Addressing the media, Congress General Secretary KC Venugopal, Communications In-Charge Jairam Ramesh, and Spokesperson Pawan Khera outlined the key takeaways from the discussions held during the meeting.
The leaders revealed that the CWC deliberated extensively on various issues concerning the party's future direction and strategies. The major points discussed included:
1. Organizational Revamp:
The Congress emphasized restoring accountability among its leaders at every level. It was decided that an organizational revamp would be carried out to strengthen the party's presence and performance on the ground.
2. Massive Political Campaigns:
To reconnect with the masses, the party has planned a series of campaigns and events, including:
- Nationwide rallies and padayatras to be held on December 27, 2024, and January 26, 2026.
- A special campaign titled Jai Bapu, Jai Bhim, Jai Samvidhan aimed at addressing threats to the Constitution and raising issues affecting the common man.
3. Upcoming AICC Session:
The All India Congress Committee (AICC) will hold its next session in Gujarat in April 2025, which is expected to set the tone for the party's strategy leading into upcoming elections.
The Congress leaders also expressed serious concerns regarding the transparency and impartiality of the Election Commission of India (ECI). They specifically pointed to the recent elections in Maharashtra and Haryana, alleging that the process was manipulated.
Jairam Ramesh stated, “Both the Maharashtra and Haryana elections were doctored. These were not free and fair elections at all. The attitude and functioning of the ECI in these states raise serious doubts about their commitment to democratic principles.”
The CWC meeting in Belagavi holds historical significance as it commemorated 100 years since Mahatma Gandhi presided over the Congress session in Belgaum in 1924. The leaders used the occasion to reflect on Gandhi’s vision for India and pledged to uphold the values of justice, equality, and democracy that he stood for.
With the announcement of these initiatives and campaigns, the Congress party aims to reinvigorate its base and challenge the ruling government on critical issues.
Watch: Press briefing by Shri @kcvenugopalmp, Shri @Jairam_Ramesh and Shri @Pawankhera after the conclusion of CWC meeting in Belagavi, Karnataka. https://t.co/8SI8xhItEl
— Congress (@INCIndia) December 26, 2024
बेलगावी में हुई विस्तारित CWC की ‘नव सत्याग्रह’ बैठक में हमारा नव संकल्प - संविधान की रक्षा के लिए हम संगठित हैं, संकल्पित हैं, समर्पित हैं! pic.twitter.com/QK1JwwgU4G
— Rahul Gandhi (@RahulGandhi) December 26, 2024
