The landing platform of the Chandrayaan-2 mission at the last stage of the moon landing deviated from the optimal trajectory and stopped transmitting telemetry. ISRO said it is analyzing data received before signal loss. The landing platform also included the Pragayan lunar rover. Broadcast landing took place on the YouTube channel ISRO.
Chandrayaan-2 is India’s first attempt to land the spacecraft on the lunar surface. The mission consists of three devices: the Vikram landing platform, the Pragayan lunar rover and the orbiter, which separated on September 2 from the landing platform and remained in orbit with parameters 125 by 96 kilometers. The mission was repeatedly delayed, but was eventually launched at the end of July 2019.
Five landing engines and eight more orientation engines were installed for landing at Vikram. Landing took place in several stages, and it took about 15 minutes to complete.
After the main stage of braking, the device had to hover above the surface to select the final landing area. However, at a distance of about a kilometer from the surface and at a vertical speed of the device of about 60 meters per second, the flight control center lost contact with the device. In addition, according to telemetry data, it is clear that after lowering to a height of 2.1 kilometers, the vehicle began to deviate from the optimal landing trajectory. After some time, ISRO representatives confirmed the loss of signal and said that they were analyzing telemetry data.
Amateur astronomers tracked the telemetry of the device through radio telescopes on Earth and noticed a sharp change in the signal before it was lost.
Both devices were designed to carry out a scientific program using their tools. In the landing platform, tools were installed to study the thermal conductivity of the lunar soil and the temperature distribution in it, as well as to record seismic events. X-ray and laser-spark spectrometers were installed in the moon rover to study the composition of the soil in the landing area. A complete list of equipment is published on the ISRO website.
The apparatuses of the Chandrayan-2 mission were designed to operate during one lunar day, amounting to about 14 Earth days. After that, they should have been in the shade and the temperature in them would have decreased to critical values (about −180 degrees Celsius), too low for the components of the landing platform and moon rover to work.
By landing Chandrayaan-2, India would be the fourth country to achieve a soft landing on the moon. The first such state was the USSR, which in February 1966 planted the Luna-9 automatic interplanetary station on the lunar surface. Soon after, after 3.5 months, the American station “Surveyor-1” sat on the moon. The third country to land the apparatus on the moon was China, which achieved this in December 2013 as part of the Chang’e-3 mission. Earlier, it was assumed that Israel would become the fourth country with an apparatus on the moon, but the Israeli Bereshit probe crashed in April 2019 while trying to land.