BAKU, Azerbaijan — The liftoff time for India’s historic Chandrayaan-3 lunar lander was shifted 4 seconds to avoid close approaches to other space objects.
Chandrayaan-3 launched July 14 on a LVM-3 heavy-lift rocket from Satish Dhawan Space Centre into an initial highly-elliptical Earth orbit.
This began a circuitous journey to the moon which culminated within the lander making the best latitude lunar landing and making India the fourth country to securely soft land on the moon.
The nominal launch time was nevertheless modified after evaluation of the orbits of tracked space objects.
“Based on collision avoidance evaluation the liftoff time was shifted by 4 seconds in order that there was no collision threat,” Anil Kumar, chief general manager of protected and sustainable space operations management on the Indian Space Research Organisation (ISRO), said on the 74th International Astronautical Congress (IAC) here in Baku, Oct. 6.
“It is a mandatory practice, not just for ISRO but for all space launch vehicles. That’s, before launch, the liftoff ought to be cleared,” Kumar said.
“The variety of space objects in orbit, especially low Earth orbit, is so high. U.S. Space Force is tracking and cataloging greater than 30,000 objects with a size of greater than 10 centimeters.
“For this LVM-3 launch on that individual day… once we analyzed, we found that through the first orbital phase of Chandrayaan-3 many objects, including operational objects, were coming closer than one kilometer.”
This led to a shift of launch time by 4 seconds to avoid plenty of close approaches.
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Chandrayaan-3 was then successfully launched into an orbit just like a geostationary transfer orbit. This was raised plenty of times before a translunar injection burn and, after this, captured into an elliptical lunar orbit. This was then lowered to permit the spacecraft to line up its landing attempt for Aug. 23.
The small print were provided at a late breaking news event at IAC. Initial science results from Chandrayaan-3’s Vikram lander and Pragyan rover data collection during their solo operational day on the moon were discussed, including the first-ever measurements of the near-surface lunar plasma environment near the lunar south pole.
Plasma levels were found to be sparse, with tens to tons of of electrons per cubic centimeter. An in depth evaluation is in progress, with potential implications for what frequencies ought to be used for lunar radio communications.
A propulsive “hop” performed Sept. 2 by Vikram also helped ISRO repeat science measurements in a brand new location, 40 centimeters from the unique landing point. This included recent temperature measurements from the Chandra’s Surface Thermophysical Experiment (ChaSTE) thermal conductivity and temperature payload.
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The maneuver, which echoed the hop by the U.S. Surveyor 6 mission in 1967, also provided a likelihood to further confirm accuracy and performance of the science payloads.
Scientists had hoped that solar-powered Vikram and Pragyan would reawaken in late September after sunrise following the deep cold of lunar night, despite an absence of radioisotope heater units. ISRO attempted to contact the pair but without success.