PROJECT SUMMARY: Xcalibur, a Vertical Takeoff TSTO RLV Concept with a HEDM Upperstage and a Scram-Rocket Booster

SEI designed a new 3rd generation, two-stage-to-orbit (TSTO) reusable launch vehicle (RLV) as an exploratory concept for NASA MSFC. The Xcalibur concept represents a novel approach due to its integration method for the upperstage element of the system. The vertical-takeoff booster, which is powered by rocket-based combined-cycle (RBCC) engines, carries the upperstage internally in the aft section of the airframe to a Mach 15 staging condition. The upperstage is released from the booster and carries the 20Klbs of payload to low earth orbit (LEO) using its high energy density matter (HEDM) propulsion system. The booster system is enabled by its main propulsion system which utilizes four RBCC engines. These engines operate in four distinct modes: air-augmented rocket (AAR), ramjet, scram-rocket, and all-rocket. The booster operates in AAR mode from takeoff to Mach 2.5, with ramjet mode operation from Mach 2.5 to Mach 4. The rocket re-ignition for scram-rocket mode occurs at Mach 4, with all-rocket mode from Mach 14 to the staging condition. The extended utilization of the scram-rocket mode greatly improves vehicle performance by providing superior vehicle acceleration when compared to the scramjet mode performance over the same flight region. The booster element is capable of returning to the original launch site in a ramjet-cruise mode.

More information can be found in the document archive. A press release is also avaiable. Additional images are avaiable in the gallery section of the website.