The Indian Space Research Organisation (Isro) has said that it saved the Chandrayaan-2 orbiter from colliding with Nasa’s Lunar Reconnaissance Orbiter (LRO) over the Moon’s north pole. Isro performed a Collision Avoidance Manoeuvre on Chandrayaan-2 orbiter in October to avoid the incident that could have triggered a major debris field and massive loss for the agency.
Analysis showed that the separation between the two spacecraft hovering above the Moon would have been less than 100 metres and the closest approach distance would be only about three kilometres. The information was released nearly a month after the collision was expected to happen on October 20 at 11:15 am IST.
“Both the agencies deemed that the situation warranted a collision avoidance manoeuvre (CAM) to mitigate the close approach risk, and it was mutually agreed that Chandrayaan-2 Orbiter would undergo the CAM,” Isro said in a statement.
The manoeuvre was scheduled on October 18 and was designed to ensure a sufficiently large radial separation at the next closest conjunction between the two spacecraft. Chandrayaan-2 executed the maneuver at 8:22 pm IST on the same day following which engineers performed post-manoeuvre tracking of the orbiter, reconfirming that there would be no further close conjunctions with LRO in the near future with the new orbit.
Both Chandrayaan-2 and Nasa’s lunar orbiter go around the Moon in a nearly polar orbit and hence, both the spacecraft come close to each other over the Lunar poles.
“It is common for satellites in Earth Orbit to undergo Collision Avoidance Manoeuvres to mitigate collision risk due to space objects including space debris and operational spacecraft. Isro regularly monitors such critical close approaches and executes CAMs for its operational satellites whenever the collision risk is assessed to be critical. However, this is the first time such a critically close conjunction was experienced on a space exploration mission of Isro, which necessitated an evasive manoeuvre,” the agency added.
The Chandrayaan-2 orbiter has been circling the Moon collecting critical data even after the mission failed following a crash landing on the surface two years ago. However, the orbiter is of critical importance to India since it will be used with the Chandrayaan-3 mission as well.
Isro is likely to launch the much-awaited Chandrayaan-3 mission to the Moon in the third quarter of 2022. The new timeline was revealed by Minister of State (Independent Charge) Science & Technology Dr Jitendra Singh earlier this year, who said, “work on Chandrayaan-3 is in progress.”
Chandrayaan-3 was earlier slated to be launched in 2021. However, the Covid-19 lockdown affected several projects of ISRO including the lunar mission.
Chandrayaan-3 is critical for Isro as it will demonstrate India’s ability to make landings for further interplanetary missions.