“A total of 2,533 objects were placed in orbit from 179 launches in 2022 as against 1,860 objects from 135 launches in 2021 — a 32% increase in successful launches and a 36% increase in the number of objects inserted in orbit were witnessed. Four major on-orbit break-up events added more than 360 fragmented objects to the space debris population,” Isro said.
Elaborating on the Indian scenario, the space agency said till 2022, 124 Indian satellites, including those from private operators/academic institutions, have been launched. As of January 1, 2023, the government owns 23 and 29 operational satellites in LEO (low earth orbit) and GEO (geostationary orbit), respectively.
13 satellites re-entered
“Chandrayaan-2 orbiter is active in lunar orbit. During the year, 13 satellites re-entered the atmosphere. The rocket body (uppermost stage of a launch vehicle) of the PSLV-C8/advance avionics module (launched on April 23, 2007) re-entered Earth on July 19, 2022,” Isro said.
At the end of 2022, of the 69 rocket bodies from Indian launches, 45 are still orbiting and 61 fragments of PS4 stage of PSLV-C3 (launched on October 22, 2001, fragmented in space on December 19, 2001) are orbiting in space.
There were four successful launches by Isro in 2022. Eight Indian satellites and four rocket bodies were placed in orbit. Indian communication satellite CMS-02 was launched from French Guiana by an Ariane launch vehicle. SSLV-D1 could not place any object in orbit.
COLA & Delayed Launches
Isro added that Collision Avoidance (COLA) analyses for lift-off clearance of launch vehicles were carried out as part of the mandatory launch clearance protocol.
“The nominal lift-off of PSLV-C53 was deferred by two minutes based on the COLA analysis to avoid potential close conjunctions within 5km with COSMOS 2251 debris, ICEYE-X6 satellite and a few Starlink satellites 3787, 2701, 2090, during the ascent phase of the launch vehicle and the initial orbital phase of the satellites,” Isro said.
The requisite co-ordination with the operators of the functional satellites was ensured for spaceflight safety. As no close-approach risks were detected, the nominal lift-off timings were cleared for other launches (PSLVC52, PSLV-C54 & LVM3-M2).
Decommissioning & Disposal
INSAT-4B, launched on March 11, 2007, was decommissioned on January 24, 2022, after being raised to a super synchronous orbit, a graveyard, and a disposal orbit band in compliance with the IADC (Inter-Agency Space Debris Coordination Committee) guidelines on post-mission disposal of GEO objects.
RISAT-2, launched on April 20, 2009, was operational till September 2022 at an altitude of 350 km. The spacecraft re-entered Earth’s atmosphere on October 30, 2022, while the Megha Tropiques-1 satellite (MT1), launched on October 12, 2011 was deorbited with a series of manoeuvres during August-December 2022.
CAMS & More
As reported first by TOI in February, 2022 saw Isro perform 21 collision avoidance manoeuvres to protect its space assets.
Confirming this, Isro said: “The number of close approach alerts received, and the number of CAMs performed by Isro also increased. This trend is expected to continue. The associated penalties for CAM, such as fuel expenditure, disruption of payload operations, operational overheads, and frequent coordination with external operators, are also anticipated to increase.”
In the absence of a universally accepted Space Traffic Management (STM) framework, Isro said resolving multiple conjunctions between operational satellites is expected to add operational complexities in the future.
