ISRO is launching a new satellite series – the ‘Indian Data Relay Satellite System’ (IDRSS). With IDRSS, ISRO will be able to track and communicate with its space assets and join the elite list of nations like The US, Russia, China and Europe.
Designed to track and be in constant touch with Indian satellites, particularly those situated in low-earth orbits with limited coverage of Earth, the IDRSS is deemed to play a vital role in the coming years, especially to ISRO.
In the next couple of years, the Indian Space Research Organisation (ISRO) navigates an impressive blueprint seeing cutting-edge LEO missions like space docking, space stations along with expeditions to the Moon, Mars and Venus.
According to K.Sivan, ISRO Chairman and Secretary, Department of Space, the IDRSS will further be of use in supervising launches.
The prime beneficiary would undoubtedly be the crew members of the Gaganyaan mission of 2022 who will be able to stay, constantly and completely in touch with mission control through the course of their excursion.
“When we have the Gaganyaan mission, we want it to be covered and be visible 100%, so that action can be taken in any exigency,” Sivan added.
Initiation of Work On IDRSS
Work has begun on the two IDRSS satellites that were initially planned. The first to be completed is scheduled to be sent towards the end of this year, 2020. This precedes the pre-Gaganyaan experimental unmanned space flight which is set to have a humanoid dummy.
The second satellite will follow in the year after, in 2021. The two combined will present almost total tracking, along with the sending and receiving of information from the crew round the clock.
The older space powers like the U.S. and Russia had started their own relay satellite systems back in the late 1970s-80s, with a few already having around 10 satellites each. These have been used to monitor the International Space Station and Mir to dock trips with them and the Hubble Space Telescope.
Sivan elaborates that the IDRSS satellites of the 2,000 kg class would be launched on the GSLV launcher to geostationary orbits situated around 36,000 km away. In these apparent fixed orbits, the area covered by the satellites would be the same as on earth. A satellite in GEO covers a third of the earth below; thereby three of them provide total coverage.
IDRSS is Imperative
When a human mission is launched and when the crew craft orbits Earth from a distance of 400 km, there must be at least one ground station that should see and track it. With the available ground stations, however, that does not appear to be the case.
In the absence of data relay satellites, ISRO would be necessitated to create a large number of ground stations everywhere. Either this or they would have to hire them globally and even then, the crewed spacecraft would not be visible at all times.
Sivan adds, “We require the IDRSS system when our astronauts are in space. But I would prefer the relay spacecraft to be in place even before we launch the unmanned mission.”
With the U.S. setting out its third generation advanced fleet of Tracking and Data Relay Satellites (TDRS), Russia has its Satellite Data Relay Network while Europe builds its own European Data Relay System, even as China proceeds into its second generation Tianlian II series.
In a global front too, the IDRSS then becomes an imperative implementation to further not only ISRO’s but India’s path of development and discovery.