Fourth X-37B Flight to Test Hall Thruster

The fourth X-37B reusable space plane will carry a Hall thruster experiment onboard, according to an April 27 release. The experiment—a collaboration between the Air Force Research Laboratory, Space and Missile Systems Center, and the Rapid Capabilities Office—will “enable in-space characterization of Hall thruster design modifications,” which will be used to improve similar units onboard Advance Extremely High Frequency communication satellites, states the release. “Space is so vitally important to everything we do. Secure comms, ISR, missile warning, weather prediction, precision navigation, and timing all rely on it, and the domain is increasingly contested,” said Maj. Gen. Tom Masiello, AFRL commander. “A more efficient on-orbit thruster capability is huge. Less fuel burn lowers the cost to get up there, plus it enhances spacecraft operational flexibility, survivability, and longevity.” The Air Force has two X-37 vehicles in its fleet and Air Force Space Command boss Gen. John Hyten said USAF would continue to use the planes “for awhile” as the service attempts to figure out “the re-usability aspect of space.” The third mission concluded in October 2014 after 674 days on orbit. It’s not clear when the fourth mission will launch.