WASHINGTON — NASA’s Project Constellation program has been overhauled to include a slightly smaller Crew Exploration Vehicle (CEV) and a new human-rated booster with an Apollo-era upper stage engine.
Project Constellation is the name NASA has given for the effort to develop hardware necessary to replace the space shuttle and return astronauts to the Moon late next decade.
NASA still intends to make use of the solid-rocket booster technology that has helped lift the space shuttle off the pad for a quarter century. But the agency recently approved CEV launcher plans calling for development of a new five-segment solid-rocket booster instead of the four-segment motor currently in production.
NASA also has dropped plans to power the so-called Crew Launch Vehicle’s upper stage with a Space Shuttle Main Engine modified to start in flight, opting instead to go with an updated version of the J-2 engine that was used on NASA’s Saturn 5 rocket.
Project Constellation Manager Jeffrey Hanley briefed engineers at Marshall Space Flight Center in Huntsville, Ala., on these and other changes Wednesday, according to individuals who spoke on the condition of anonymity because the changes had not yet been officially announced.
These changes follow NASA’s decision, announced just last week, to drop the requirement for a liquid oxygen/methane engine on the CEV service module and lunar lander, leaving it up to the two competing CEV contractor teams — led by Lockheed Martin and Northrop Grumman — to propose whatever propulsion system they deem best.
Other newly approved changes to the CEV, according to sources familiar with the details, include reducing the diameter of the vehicle from 18 feet (5.5 meters) to 16.4 feet (5 meters) for additional weight savings and using existing Russian docking hardware for missions to the International Space Station (ISS). Previous plans called for using a U.S.-developed system.
These sources said NASA’s overhauled space transportation plan probably will not save money in the near term, but should prove cheaper in the long run because both the J-2 engine and five-segment solid-rocket booster are needed for the heavy-lift cargo vehicle NASA is developing for the lunar sorties it still hopes to begin as soon as 2018. By going with the J-2/five-segment booster combination for the initial CEV flights, NASA can skip development of an air-lit Space Shuttle Main Engine and put its resources toward producing an expendable version of that engine, which NASA still plans to use for the heavy-lift rocket’s main stage.