A modified version of the retired Space Shuttle main engine was tested Monday at Stennis Space Center as part of research to develop an experimental spaceplane being developed by Boeing in partnership with Aereojet Rocketdyne and the Defense Advanced Research Projects Agency.

The craft is being called the Phantom Express, and will be powered by the AR-22, which is a modified version of the RS-25 previously used on the Space Shuttle prior to the program’s retirement.

Jeff Haynes, AR-22 program manager for Aerojet Rocketdyne, said that the engine they are using is not the same as the modified version of the Space Shuttle engine being used in the Space Launch System, but does have an updated controller.

The sixth of ten tests was completed Monday. Conducting ten tests in ten days will help show that regular use of the engine has a minimal risk. So far, the team is averaging a turnaround time of the engine of between 22 to 25 hours, which includes drying and performing adjustments to the engine. Additional tests will be conducted throughout the week.

Through the testing, the team hopes to show that with the use of a reusable booster engine, launching satellites can be more cost effective and require minimal prep time, said Experimental Spaceplane Program Manager Scott Wierzbanowski.

Research into reducing the cost and responsiveness of launching satellites began about five years ago, said Steve Johnston, director of Boeing Phantom Works Advanced Space Exploration division.

That research led to development of a 100-foot-long unmanned spacecraft with a 62-foot wingspan capable of traveling ten times the speed of sound called the Phantom Express, Johnston said. According to a video on Boeing’s website, the craft will reach the edge of space where a detachable pod on top will separate and launch the satellite further into space. The Phantom Express will then return to Earth to be used again, landing like the Space Shuttle used to. The website says the craft will be capable of launching a satellite weighing between 3,000 to 5,000 pounds into low Earth orbit.

Some of the technology used to develop the craft came from the commercial airline sector.  By using this technology, a satellite can be launched in a matter of days, instead of requiring months of planning, Johnston said. While there are no concrete plans in the works, this technology could be transferred for other uses, such as transporting people from one place to another.

The plan is to finish testing by the end of the week, and enter test flights of the vehicle by 2021, Johnston said.