Bringing Launch Costs Down to Earth

Abstract

This article discusses the three federally funded projects that are underway to develop new rocket engines that can make it more affordable to send payloads into orbits. The new RS-68 propulsion system is Rocketdyne's entry in competition to power the US Air Force's new heavy-lift booster. The most ambitious of the new propulsion system designs is Rocketdyne's XRS-2200 linear aerospike engine, a seemingly nozzle-less oxygen/hydrogen powerplant that is designed to send the autonomously controlled NASA X-33 lifting body into orbit. The X-33 is being developed by Lockheed Martin Skunk Works, Palmdale, CA. The key for new launch vehicles, whether they're expendable or reusable, is to get the costs down. The article also highlights that the payload that can be lofted by a launch vehicle depends in large part on engine performance and the ratio of propellant to structural weight. Bell nozzles are designed to offer the best compromise of shape and length for a vehicle and flight path. Rocketdyne's R-68 engine is to be 17 feet tall and 8 feet wide at the base. The key to the R-68 engine design was the selection of hydrogen as the propellant rather than kerosene.