Bringing Back the Upper Stage: The Hardest Problem in Reusable Rockets, Now Being Attempted Near Sriharikota

Why the Upper Stage Is the Hard Part

Most rockets are used once. Each stage burns its fuel, separates and is lost. SpaceX's Falcon 9 changed this for the first stage, the booster, by landing it and flying it again, which reduced launch costs. Recovering the upper stage, the part that actually reaches orbit, is a much harder problem and few rockets have done it.

Why the Booster Is Easier

The booster separates relatively early, lower down and at a lower speed. Its return is demanding but manageable. The upper stage keeps accelerating until it is close to orbital velocity. To come back, it has to survive re-entry heating like a returning spacecraft, which means a heat shield, extra structure and fuel reserved for landing.

All of that adds weight and every kilogram used for recovery is a kilogram that cannot be used for payload. The Guild's own stated figures show the trade-off. The company says RCM1 is designed to carry 8 tonnes to low Earth orbit in fully reusable form and 24.8 tonnes if expended.

On those figures, full reusability would cost about two-thirds of the rocket's maximum payload. The bet is that flying the same hardware many times will cost less than building a new rocket for each launch. An airliner is a useful comparison, with a limit.

Aircraft are cheap to operate because they are reused and full reusability aims to make rockets more like aircraft. The comparison breaks down because aircraft do not go through orbital re-entry, so they do not need the heat protection that makes upper-stage recovery so heavy and so difficult.

What The Guild Has Built The Anchorage is a

150-acre site in Space City, Tirupati district, about 40 km from the Satish Dhawan Space Centre at Sriharikota. Its first facility, the Pegasus Horizontal Static Test Facility, is already commissioned and can test pressure-fed engines at pressures up to 210 bar.

A vertical test facility for the booster's clustered engines is under development. RCM1 will use two semi-cryogenic engines, which burn liquid oxygen with refined kerosene. The Pegasus engine, rated at 80 kN, powers the reusable upper stage.

The Stallion engine, a 1.2 MN gas-generator design, powers the booster.

Where India Stands

India's private launch sector is developing quickly. Skyroot Aerospace flew the suborbital Vikram-S in November 2022 and Agnikul Cosmos flew Agnibaan SOrTeD, with a 3D-printed semi-cryogenic engine, in May 2024. ISRO itself is working on reusability, through the winged RLV-TD "Pushpak" and a reusable first stage for its Next Generation Launch Vehicle.

The Guild is aiming further, at full reuse, although it has not yet flown and its stated test and launch dates remain plans. This is possible because of Indian Space Policy 2023, which allows private firms to develop launch vehicles end to end, with IN-SPACe as the single-window authorising agency.

There is one significant gap: the Space Activities Bill, which would set out liability rules for issues such as debris and accidents, is still pending. For GS3, the key point is that reusability is not one technology but two very different problems.

India's private sector is now working on the harder one, while the legal framework for liability has not yet caught up.