Leonard David's INSIDE OUTER SPACE

X-37B now on the 6th mission of the space plane program.
Credit: Boeing

The Earth-circling U.S. military X-37B robotic space drone has broken a record, setting a new long-duration trek in space for the program.

The Orbital Test Vehicle (OTV-6), also called USSF-7 for the U.S. Space Force, was launched on May 17, 2020 atop an Atlas-V 501 booster and has now sailed past 780 days of time on orbit.

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

The X-37B Orbital Test Vehicle mission 4 (OTV-4), the Air Force’s unmanned, reusable space plane, landed at NASA’s Kennedy Space Center Shuttle Landing Facility May 7, 2017.
Credit: USAF

Classified status

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

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

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.

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.

Recovery crew members process the X-37B Orbital Test Vehicle at Vandenberg Air Force Base after the program’s third mission complete.
Credit: Boeing

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.

Flight roster

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 fly to a wheels-stopped landing, and where, is a guess, but likely Kennedy Space Center.

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.

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.

Reusable vehicle

Credit: U.S. Air Force/Boeing

Presently, as far as known, there are just two X-37B vehicles in the program.

A Boeing fact sheet notes that “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.”

X-37B hangar at Kennedy Space Center.
Credit: Michael Martin/SAF