BENGALURU: When OrbitAid’s 25-kg Ayulsat lifts off aboard Isro’s PSLV-C62 Monday, the mission’s success will bring India a step closer to becoming the second country in the world to demonstrate on-orbit satellite refuelling, a capability so far claimed only by China, reports Chethan Kumar. Last year, China carried out a similar demonstration, but details remain limited and official disclosures sparse. No other spacefaring nation, including the US, has publicly demonstrated the technology in orbit. However, US firm Astroscale is developing a refuelling technology but is yet to launch. Ayulsat won’t demonstrate a full on-orbit re-fuelling. It is designed as a target satellite to validate fuel transfer in the space environment. Unlike more complex servicing missions involving two spacecraft, OrbitAid’s first step focuses on internal refuelling within a single satellite, allowing engineers to study how fluids behave in microgravity under real orbital conditions. OrbitAid founder and CEO Sakthikumar R told TOI the first refuelling is expected to take place within four hours of launch.