India’s national space agency, the Indian Space Research Organization (ISRO), is currently engaged in a collaborative effort with the Bhabha Atomic Research Centre (BARC) to develop an advanced nuclear-powered propulsion system, sources have revealed.
While chemical engines, commonly employed in satellite thrusters, serve their purpose effectively, they have limitations when it comes to deep space exploration, particularly interplanetary missions. The challenges lie in their restricted fuel capacity and inability to rely on solar power due to the vast distances that hinder sunlight from reaching solar panels.
To overcome these hurdles, the development of nuclear-powered engines has become imperative. Reliable sources indicate that ISRO and BARC are working together to create Radio thermoelectric generators (RTGs). This undertaking has been identified as a significant task with an urgent need for completion, as stated by an insider.
It is essential to note that the nuclear engines under development are not akin to nuclear fission reactors used for electricity generation. Instead, the RTGs employ radioactive materials, such as Plutonium-238 or Strontium-90, which emit heat during the process of decay.
The engine essentially consists of two key components—the radioisotope heater unit (RHU), responsible for generating heat, and the RTG, which converts the generated heat into electricity.
The heat produced is transferred to a ‘thermocouple,’ a substance that generates an electric potential when subjected to a temperature gradient. To illustrate this simply, envision a rod—when one end is hot and the other end is cooler, a voltage is generated across the rod (known as the Seebeck Effect). This voltage can be utilized to charge batteries, providing the necessary propulsion for a satellite. ISRO’s objective is to develop a 5W RTG, according to sources.
“RTGs offer the advantage of independence from solar proximity and planetary alignment. This characteristic significantly reduces limitations such as the reliance on specific ‘launch windows’ that scientists must adhere to,” explains Nitansha Bansal, a cyber security expert affiliated with Columbia University, in an article published by the Observer Research Foundation (ORF).
It is worth noting that RTGs are not an entirely novel concept. Prominent US spacecraft, including Voyager, Cassini, and Curiosity, have successfully utilized RTGs as their power source.