Air Force X-37B space plane.
Credit: Boeing

That secretive U.S. military X-37B robotic space drone is now edging up on 600 days circling the Earth.

The Orbital Test Vehicle (OTV-6) is also called USSF-7 for the U.S. Space Force, and was launched on May 17, 2020 by an Atlas-V 501 booster.

OTV-6 is the first to use a service module to host experiments. The service module is an attachment to the aft of the vehicle that allows additional experimental payload capability to be carried to orbit.

Credit: Boeing/Inside Outer Space Screengrab

Onboard payloads

While the Boeing-built resuable robotic space plane’s on-orbit primary agenda is classified, some of its onboard experiments were identified pre-launch.

One experiment onboard the space plane that continues to gather data is from the U.S. Naval Research Laboratory (NRL). It’s an investigation into transforming solar power into radio frequency microwave energy. The experiment itself is called the Photovoltaic Radio-frequency Antenna Module, PRAM for short – and a step forward in investigating the promise of satellite power beaming to Earth.

In addition, two NASA experiments are also onboard the space plane to study the effects of the space environment on a materials sample plate and seeds used to grow food.

Along with toting NRL’s PRAM into Earth orbit, the X-37B also deployed the FalconSat-8, a small satellite developed by the U.S. Air Force Academy and sponsored by the Air Force Research Laboratory to conduct several experiments on orbit.

X-37B handout.
Credit: Boeing

Delta 9

The X-37B program is flown under the wing of a U.S. Space Force unit called Delta 9, established and activated July 24, 2020.

“The mission of Delta 9 is to prepare, present, and project assigned and attached forces for the purpose of conducting protect and defend operations and providing national decision authorities with response options to deter and, when necessary, defeat orbital threats,” a fact sheet explains. “Additionally, Delta 9 supports Space Domain Awareness by conducting space-based battlespace characterization operations and also conducts on-orbit experimentation and technology demonstrations for the U.S. Space Force.”

“Delta 9 Detachment 1 oversees operations of the X-37B Orbital Test Vehicle, an experimental program designed to demonstrate technologies for a reliable, reusable, unmanned space test platform for the U.S. Space Force,” according to the fact sheet issued by Schriever Air Force Base in Colorado.

Fact sheet aside, it recently was spotlighted by Russia’s Ministry of Defense, prompted by all the recent Russian anti-satellite news – tagging the X-37 spacecraft as showing that the U.S. “is actively developing” space weapons.

Post-landing of OTV-5 at NASA’s Kennedy Space Center Shuttle Landing Facility.
Courtesy Photo 45th Space Wing Public Affairs

Previous flights

OTV-1: launched on April 22, 2010 and landed on December 3, 2010, spending over 224 days on orbit.

OTV-2: launched on March 5, 2011 and landed on June 16, 2012, spending over 468 days on orbit.

OTV-3: launched on December 11, 2012 and landed on October 17, 2014, spending over 674 days on-orbit.

OTV-4: launched on May 20, 2015 and landed on May 7, 2015, spending nearly 718 days on-orbit.

OTV-5: launched on September 7, 2017 and landed on October 27, 2019, spending nearly 780 days on-orbit.

OTV-1, OTV-2, and OTV-3 missions landed at Vandenberg Air Force Base, California, while the OTV-4 and OTV-5 missions landed at Kennedy Space Center, Florida.

There is no word on when and where OTV-6 will return to Earth.

Check out this video from satellite watcher, Kevin Fetter, as the U.S. military space plane passes overhead on November 20, 2021 at:



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