The National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA) have been assisting the Indian Space Research Organization (ISRO) to monitor the health of the spacecraft since the Chandrayaan-3 mission’s launch on July 14.
According to Ramesh Chellathurai, a ground operations engineer at ESOC Darmstadt, Germany, “Since the launch of Chandrayaan-3, ESA has been supporting the mission by using two of the ground stations in the ESTRACK network to track the satellite in its orbit, receive telemetry from the spacecraft and forward it to the Mission Operations Centre in Bengaluru, and forward commands sent from Bengaluru to the flying satellite.”
The ESA’s 15-metre antenna in Kourou, French Guiana, and the 32-metre antenna belonging to Goonhilly Earth Station, U.K., were selected for the support, based on their technical capabilities as well as their periods of geometric visibility to the satellite.
“These two stations have been communicating with the Chandrayaan-3 mission on a regular basis, providing a complete communication channel between the Mission Operations Team in Bengaluru and the Chandrayaan-3 satellite,” Mr. Chellathurai added.
With Chandrayaan-3’s Lander attempting to land on the moon’s surface on August 23, the help of these agencies’ ground stations is now even more essential.
A third ground station in the ESTRACK network, the ESA’s 35-meter deep space antenna at New Norcia, Australia, has been built up to track and communicate with the Lander Module during the Lunar Descent phase.
Throughout the descent, the ISRO’s own ground station will have backup communication with the New Norcia antenna. In parallel with the ISRO station, it will receive updates on the condition, location, and trajectory of the Lander Module.
“It will be this telemetry that is used to confirm the success of the landing. This type of back-up support is common during the key moments of a space mission, such as a landing. After a successful landing, data collected by the mission’s Rover will be routed via the Lander Module to the ground stations. These valuable scientific data will be received by the antennas in Kourou and Goonhilly and forwarded to the Mission Operations Centre in Bengaluru,” Mr. Chellathurai said.
From Deep Space Station (DSS)-36 and DSS-34 at Canberra Deep Space Communications Complex, followed by DSS-65 at Madrid Deep Space Communications Complex, NASA’s Deep Space Network is providing telemetry and tracking coverage during the powered descent phase.
“We receive the telemetry from the spacecraft that has the data on the health and status as well as instrument measurements and pass them on to ISRO in practically real-time. We also monitor the radio signal itself for the Doppler effect, which is the primary tool for navigating the spacecraft. This is the critical information during the landing phase and tells us in real-time how it is doing,” Sami Asmar, Jet Propulsion Laboratory’s Interplanetary Network Directorate Customer Interface Manager, said.
He continued by saying that the DSN complex in California, which is directly across the globe from India and can see the Moon when the station in India cannot, is the mission’s main source of support.
