United in space: As Chandrayaan-3 prepares for touchdown, here is how NASA and ESA are working with ISRO to monitor its health and guide it

On 14th July, Chandrayaan-3 was launched from the Satish Dhawan Space Centre in Andhra Pradesh’s Sriharikota by the Indian Space Research Organisation (ISRO). Since then, ground stations of the National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA) have supported the Indian space agency in monitoring the health of Chandrayaan-3.

Chandrayaan 3 comprises a Lander and a rover. The main objective is to conduct scientific studies on the surface of the moon for 14 days period. While ISRO will be using its deep-space communication antenna for the project, other space agencies will assist in the project.

ISRO has a 32-meter deepspace tracking station in the country that enables the space agency to track, command, and receive telemetry and scientific data from the spacecraft. However, in several instances, the spacecraft gets beyond the range of ISRO’s antenna. At that time, communicating with the spacecraft will not be possible.

Constructing large-scale antennas and control stations worldwide is an expensive project. Space agencies and commercial entities worldwide seek support from the partner organisations’ ground stations to mitigate the cost of establishing new antennas. International collaboration in space exploration holds the utmost importance because of its exponential cost.

Speaking to the Hindu, ground operations engineer at ESOC Darmstadt, Germany, Ramesh Chellathurai, said, “Since the launch of Chandrayaan-3, ESA has been supporting the mission by utilizing 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.”

Signal acquired! 📡〰️〰️〰️🛰️📶

We hear you loud and clear #Chandrayaan3! 🇮🇳

Data are now flowing down from orbit to our Kourou station in French Guiana.

From there, they are forwarded to @isro in India via our ESOC #MissionControl centre in Darmstadt, Germany. pic.twitter.com/VxKyrLMXQN

— ESA Operations (@esaoperations) July 15, 2023

Based on the technical capabilities and geometric visibility of the satellite, two stations of ESA were selected to provide support. A 15-meter antenna in Kourou, French Guiana, and the 32-meter antenna of Goonhilly Earth Station, UK, are continuously monitoring ESA and rallying the information to ISRO.

Chellathurai said, “These two stations have been communicating with the Chandrayaan-3 mission regularly, providing a complete communication channel between the Mission Operations Team in Bengaluru and the Chandrayaan-3 satellite.”

The ground stations become crucial on the day of the landing. Apart from the two stations, ESA’s 35-metre deepspace antenna in New Norcia, Australia, tracks and communicates with the Lander Module at the time it starts to descend to the moon’s surface. During the process, It serves as a backup station for ISRO’s own ground station. Both ISRO and New Norcia antenna will receive information about the Lander Module’s health, location, and trajectory simultaneously.

Like all our deep space stations, New Norcia is controlled remotely from our ESOC #MissionControl centre in Germany.

It is managed locally by our Australian partners, @CSIRO.

We’re all set for landing day! #Chandrayaan_3 #Moon #ISRO #ESA pic.twitter.com/wKDj55f6VY

— ESA Operations (@esaoperations) August 21, 2023

Such backup support is common during key moments of space missions. Once the Rover lands on the moon, the information will be routed to the connected ground stations via the Lander Module. The information collected by Kourou and Goonhilly will be forwarded to the Mission Operation Centre in Bengaluru.

NASA to provide telemetry and tracking coverage during descent phase

On the other hand, NASA’s Deep Space Network’s Deep Space Station (DSS)-36 and DSS-34 at Space Communications Complex and DSS-65 at Madrid Deep Space Communications Complex would provide telemetry and tracking coverage during the descent phase.

The information collected by NASA’s stations, including health and status and instrument measures, are passed to ISRO’s ground station in real-time. These stations also monitor the radio signal for the Doppler Effect, which is the primary tool for navigation of the spacecraft. As the DSN Complex in California is on the exact other side of the Earth from India, it can be in view of the Moon when India cannot see it.

NASA’s Deep Space Network has the world’s largest and most sensitive scientific telecommunication system. It comprises a global array of immense radio antennas crucial for interplanetary spacecraft missions. These antennas provide insights through radar and radio astronomy observations that help understand the solar system and the universe.

Space agencies collaborate to assist each other

India is part of The Coordination Group for Meteorological Satellites (CGMS) with China, Europe, Japan, the United States, Russia, and the Republic of Korea. Other partners include the World Meteorological Organization (WMO) and UNESCO’s Intergovernmental Oceanographic Commission (IOC). Recently, CGMS celebrated 50 years of collaboration in different fields related to meteorological satellites. CGMS was established in 1972 by satellite agencies from Europe, Japan, and the United States to coordinate the operation and use of geostationary satellites. Over the years, the number of members and applications increased.

Similarly, during different missions, space agencies worldwide take support from each other as it is expensive to establish their own antenna network. Collaborations help reduce costs and share information about space projects that help in future endeavors.