Testing of AR-22 underway

STENNIS SPACE CENTER, Miss. – An Aerojet Rocketdyne AR-22 rocket engine designed for use in a reuseable military spacecraft, the unmanned Phantom Express, was tested Monday at NASA's rocket engine test facility in South Mississippi. The engine, a variant of the RS-25 that was a workhorse in the Space Shuttle program, is being tested over a 10-day period. It is fired up for 100 seconds and then fired again 24 hours later. Monday's was the sixth of what is anticipated to be 10 test fires. (Sources: multiple, including WLOX-TV, 07/02/18, AP via Minneapolis Star-Tribune, 07/03/18) The first AR-22 assembly was completed in early June. Previous