Reusable Booster System

History

The Air Force initially set aside funding for the Reusable Booster System (RBS) program, planning to award up to three contracts. Winners would then compete for specific experiments and demonstrations related to the technology and processes of a reusable booster. Proposals were due by March 19, 2011. The Air Force had a notional plan for a fleet of eight RBS vehicles, operating from Vandenberg Air Force Base in California and Cape Canaveral Air Force Station in Florida.

Three companies submitted designs: Andrews Space, Boeing, and Lockheed Martin. The first flight experiment, planned for 2014, involved a vertical takeoff, a downrange flight at just over Mach 1, and a horizontal landing. In December 2011, Lockheed Martin received a contract to build a flight demonstration vehicle called the RBS Pathfinder, slated for completion in 2015, under the Air Force Research Laboratory's RBS Flight and Ground Experiments program.

Lockheed began initial short-duration rocket engine tests in 2012. By September 2012, Phase 2, which included demonstrating the rocketback maneuver, was canceled. The entire program was discontinued in October 2012, citing Department of Defense funding cuts and a negative report from the National Research Council (NRC) released that same month. Only a small portion of the original $250 million budget, planned through 2019, had been spent.

The NRC report recommended that the Air Force develop and fly more than one Pathfinder test vehicle design and maintain competition among RBS concepts as long as possible to secure the best system for the next generation of space launch.

Propulsion

A joint team from Air Force Space Command, AFRL propulsion researchers, and the Space and Missile Systems Center's launch office met to weigh engine options. They debated concentrating on oxygen-rich staged combustion engines, like the Hydrocarbon Boost program, adopting an existing engine such as the TR-107, or upgrading a newer model like the J-2X or RL60 from Pratt & Whitney Rocketdyne. Whichever route they chose, the goal was to produce an engine delivering about 250,000 lbf (1112 kN) of thrust by 2020.