The Mysterious X-37B Spaceplane Lands After 780 Days in Orbit and Sets New Record

X-37B seventh mission could be its last

By Dario Leone
Dec 8 2023
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X-37B seventh mission

The Department of the Air Force Rapid Capabilities Office, in partnership with the US Space Force (USSF), launched the seventh mission of the X-37B Orbital Test Vehicle on Dec. 7, 2023 from Kennedy Space Center, Florida (but no one is saying when it’s due back).

The X-37B Mission 7 launched on a SpaceX Falcon Heavy rocket for the first time, designated USSF-52, with a wide range of test and experimentation objectives. These tests include operating the reusable spaceplane in new orbital regimes, experimenting with future space domain awareness technologies, and investigating the radiation effects on materials provided by NASA.

“We are excited to expand the envelope of the reusable X-37B’s capabilities, using the flight-proven service module and Falcon Heavy rocket to fly multiple cutting-edge experiments for the Department of the Air Force and its partners,” said Lt. Col. Joseph Fritschen, the X-37B Program Director, in a USSF news release.

X-37B Mission 7, also known as OTV-7, will expand the US Space Force’s knowledge of the space environment by experimenting with future space domain awareness technologies. These tests are integral in ensuring safe, stable, and secure operations in space for all users of the domain.

Chief of Space Operations, Gen. B. Chance Saltzman hailed these experiments as “groundbreaking,” saying, “The X37B continues to equip the United States with the knowledge to enhance current and future space operations. X-37B Mission 7 demonstrates the USSF’s commitment to innovation and defining the art-of-the-possible in the space domain.”

The NASA experiment onboard will expose plant seeds to the harsh radiation environment of long-duration spaceflight. Known as “Seeds-2,” the experiment will build upon the successes of prior experiments, paving the way for future crewed space missions.

X-37B Mission 6

X-37B seventh mission could be its last
Featuring the United States Space Force (USSF) logo for the first time, the encapsulated X-37B Orbital Test Vehicle for the USSF-52 Mission.

Previously, X-37B Mission 6 was the first mission to introduce a service module that expanded the capabilities of the spacecraft and allowed it to host more experiments than any of the previous missions. The spacecraft carried the Naval Research Laboratory’s Photovoltaic Radio-frequency Antenna Module experiment, which transformed solar power into radio frequency microwave energy, and two NASA experiments to study the results of radiation and other space effects on a materials sample plate and seeds used to grow food. The X-37B Mission 6 also deployed FalconSat-8, a small satellite developed by the US Air Force Academy and sponsored by the Air Force Research Laboratory.

The Director of the DAF RCO, William D. Bailey, praised the collaborative partnership with industry, noting, “The X-37B government and Boeing teams have worked together to produce a more responsive, flexible, and adaptive experimentation platform. The work they’ve done to streamline processes and adapt evolving technologies will help our nation learn a tremendous amount about operating in and returning from a space environment.”

X-37B previous missions

According to Air & Space Force Magazine, with each successive mission, X-37B has spent longer and longer in orbit. Its last flight lasted 908 days, from May 17, 2020, to Nov. 12, 2022. Previous missions lasted:

  • 780 days—Sept. 7, 2017, to Oct. 27, 2019
  • 718 days—May 20, 2015, to May 7, 2017
  • 674 days—Dec. 11, 2012, to Oct. 17 2014
  • 468 days—March 5, 2011, to June 16, 2012
  • 224 days—April 22, 2010, to Dec. 3, 2010

Should the trend of extended missions continue, X-37B wouldn’t land until June 2026 or later. It is unclear how many more flights the space plane can endure. In 2020, when Saltzman was still a three-star lieutenant general, he hinted that the spacecraft might be nearing its end. The X-37B, he said then, might exemplify “technology that has served its purpose and [maybe] it’s time to start looking at the next available capability.”

The secretive X-37B Orbital Test Vehicle

The secretive X-37B Orbital Test Vehicle, or OTV, is an experimental test program to demonstrate technologies for a reliable, reusable, unmanned space test platform. The primary objectives of the X-37B are twofold; reusable spacecraft technologies for America’s future in space and operating experiments which can be returned to, and examined, on Earth.


Photo credit: U.S. Air Force and Boeing

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Dario Leone

Dario Leone

Dario Leone is an aviation, defense and military writer. He is the Founder and Editor of “The Aviation Geek Club” one of the world’s most read military aviation blogs. His writing has appeared in The National Interest and other news media. He has reported from Europe and flown Super Puma and Cougar helicopters with the Swiss Air Force.
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