The NASA and ESA stations are relaying info to ISRO
As 1.4 billion Indians follow with bated breath Chandrayaan 3's descent on the Moon's surface, two international space agencies will provide support to the Indian Space Research Organisation (ISRO) in tracking the spacecraft as it inches towards history.
Space stations of the US's National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA) will be providing tracking support to the mission operations team during the descent of the lander.
To put this into context, Vikram lander, Chandrayaan 3 propulsion module and Chandrayaan 2 orbiter are in the moon's orbit, about 3.84 lakh kilometres from the earth. The earth and the Moon are rotating on their axes and revolving around the Sun. Amid the movement, antennas on the earth are tracking the lander's gradual descent. A 32-metre dish antenna, India's largest, at Byalalu near Bengaluru is tracking Chandrayaan-3.
But there are times when the lander moves to a shadow region and cannot be tracked from here. This is where deep space networks of NASA and ESA come in. This, however, is not a free service. India is paying for this, depending on how many antennas it uses and for what duration.
So, when the lander is not in the view of our antenna, the NASA or ESA communicates with the lander and relay the information to the mission operations team in Bengaluru.
It must, however, be made clear that these networks assisting ISRO have no say in what is to be done or communicated to the lander. That control rests with the mission operations team in Bengaluru and they function only as a communication link when ISRO can't access the lander through its own network.
The Chandrayaan-3 is expected to land on the surface of moon around 6 pm. Events of mass viewing have been organised across the country and people are holding prayers for the success of the mission. The suspense is particularly high after Russia's moon mission ended in a crash of its Luna-25 spacecraft Sunday.