Credit: Boeing/Inside Outer Space Screengrab

 

That Earth-circling U.S. military X-37B robotic space drone is closing in on a new long-duration record.

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 and is winging past 770 days.

Flight of a previous record-holder was OTV-5 that spent nearly 780 days on-orbit.

Encapsulated X-37B Orbital Test Vehicle for U.S. Space Force-7 mission, now in Earth orbit.
Credit: Boeing

Onboard experiments

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

One experiment onboard the space plane is from the U.S. Naval Research Laboratory (NRL), 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.

X-37B handout.
Credit: Boeing

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.

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

 

 

 

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.

The U.S. Air Force’s X-37B Orbital Test Vehicle 4 is seen after landing at NASA ‘s Kennedy Space Center Shuttle Landing Facility in Florida on May 7, 2017.
Credit: U.S. Air Force courtesy photo

Earlier flights

Here’s a roster of X-37B missions showing the increasing duration of flight time.

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.

As to when and where OTV-6 will return to a wheels-stopped landing is anybody’s guess.

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.

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

Overseeing operations

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

In a description of Delta 9, current as of September 2020:

“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 a fact sheet issued by Schriever Air Force Base in Colorado.

Delta 9 unit emblem.
Credit: U.S. Space Force

“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,” the 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.”

Vehicle features

Boeing, as the space plane maker, notes that the vehicle features many elements that mark a first use in space, including:

  • Avionics designed to automate all de-orbit and landing functions.
  • Flight controls and brakes using all electro-mechanical actuation; no hydraulics on board.
  • Built using a lighter composite structure, rather than traditional aluminum.
  • New generation of high-temperature wing leading-edge tiles and toughened uni-piece fibrous refractory oxidation-resistant ceramic (TUFROC) tiles.
  • Advanced conformal reusable insulation (CRI) blankets.
  • Toughened uni-piece fibrous insulation (TUFI) impregnated silica tiles.

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

According to a Boeing fact sheet, “the X-37B is one of the world’s newest and most advanced re-entry spacecraft, designed to operate in low-earth orbit, 150 to 500 miles above the Earth. The vehicle is the first since the Space Shuttle with the ability to return experiments to Earth for further inspection and analysis. This United States Air Force unmanned space vehicle explores reusable vehicle technologies that support long-term space objectives.”

At first designed to fly 270 days per mission, Boeing adds that “the X-37B has set progressive records for time on orbit during each of its five previous missions.”

Credit: Kevin Fetter

 

 

 

Go to this June 25, 2022 video of OTV-6 flying overhead, taken by Canadian skywatcher Kevin Fetter. “Nice to have a clear sky again, after a few cloudy one’s,” he says.

Video at: https://youtu.be/WbpLxDxVDS8

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