The TDS-01 will also trial Indian-made travelling wave tube amplifiers (TWTAs), key components for communications and remote sensing satellites. These amplifiers are expected to enhance satellite functionality, providing a platform for improved communications and data relay systems.
Efficiency Gains with Electric Propulsion
Traditional satellite thrusters require a significant amount of liquid fuel, primarily to shift from a launch orbit to a geostationary orbit and to maintain position against gravitational shifts. For instance, a typical four-ton communication satellite currently requires over two tonnes of liquid fuel for this purpose. Electric propulsion, however, drastically reduces this requirement, allowing for a lighter satellite structure.“A four-tonne satellite carries 2-2.5 tonnes of fuel. In case of electric propulsion, the fuel requirement reduces to just 200 kg,” explained Somanath. Electric propulsion systems use ionised propellant gases, such as Argon, which are powered by solar energy rather than traditional chemical fuels.
“When the fuel tank size is reduced, the size of every peripheral also comes down. It is a cumulative effect. So, this satellite will not weigh more than two tonnes but will have the power of a four-tonne satellite,” he added.
Low Thrust Drawbacks
While electric propulsion reduces the fuel burden, it generates significantly lower thrust compared to chemical-based systems. Somanath acknowledged this limitation, noting that reaching the intended orbit could take months instead of weeks. “The only issue with electric propulsion is it is very low thrust. It will take almost three months to reach the geo orbit from the launching orbit, as against one week in chemical thrusters,” he said.
The electric propulsion system (EPS) was first introduced by ISRO for the GSAT-9, also known as the South Asia Satellite, launched in May 2017. However, that system was imported from Russia, making TDS-01 a milestone for Indian-made satellite technology.
NISAR Satellite Progress
In addition to TDS-01, ISRO is also preparing for the upcoming NASA-ISRO Synthetic Aperture Radar (NISAR) satellite. This collaborative mission aims to monitor various environmental phenomena, including ecosystem disturbances, deforestation, and ice-sheet collapse. Somanath reported that work on the satellite’s radar antenna reflector had recently concluded, with the component now en route to ISRO’s spacecraft integration and testing facility in Bengaluru.”Integration of the radar antenna reflector with the satellite will take about two months,” Somanath stated, adding that the mission’s launch is slated for February.
Inputs from PTI