Shuttle Engine Returner

A modification for NASA’s SLS launch system, the Shuttle Engine Returners are small pods that would be attached to the thrust structure at the bottom of SLS, carrying two RS-25s each. Once the core stage burn is complete, the pods would be able to use their own propellant to adjust their trajectory to reenter and land at a safe location, allowing the reuse of the expensive RS-25s. This system does reduce the payload capacity of the SLS slightly, however.

This concept is based on the design of a Shuttle-derived launch vehicle from the early 1990s which would have used similar pods, though the details of that system were not fleshed out – the mention being limited to a single diagram.

Length: 16.7 meters
Wingspan: 14.1 meters
Height (gear retracted): 6.25 meters

Mass
Normal (with RS-25s): 14.678 tons
Maximum: 16.313 tons
Dry (with RS-25s): 13.977 tons

Maximum Propellant Load:
988.6 liters MMH
1011.4 liters NTO
(Normal Propellant Load is 30%)

2 x RS-25E (carried but not used by the SER)
RCS – 1kN thrusters at 240s ISP (vac.)