On 28 January, 2021, the UR Rao Satellite Centre (URSC) of Indian Space Research Organisation (ISRO) invited proposals for the three phase development of a 100 Watt Radioisotope Thermoelectric Generator (RTG).
As ISRO’s lead centre for design, development, fabrication, and testing of all Indian-made satellites, the centre envisions using RTG for power generation and thermal management of ISRO’s deep space missions. With plans of setting up a space station, and launching the first Indian human space flight mission, Gaganyaan; the first Indian solar observatory, Aditya L-1; the second Indian space telescope XPoSat; Mangalyaan-2 to Mars; Chandrayaan-3 as a reattempt to land on the Moon; and the Venus orbiter mission Shukrayaan; ISRO has embarked on a monumental journey of exploring remote and challenging environments. It has told the world that India does not want to be a nascent space player anymore.
Against this backdrop, the decision to invest in nuclear thermal propulsion (NTP) appears inevitable. RTGs are not new but the use of nuclear energy for launching rockets had been long given up, though small nuclear-powered rovers like the US’s Perseverance have been in use. RTGs were first used in space during the Cold War in 1961 for the US’s Transit-4A Mission. Since then, the erstwhile Soviet Union had launched over two dozen nuclear-powered space objects.
However, budget constraints, complicated designs, progress in alternative sources of energy, and the possibility of escalation of the Cold War led to the curtailment of nuclear propulsion projects.