U.S. military’s X-37B space plane is encapsulated in launch faring and features the United States Space Force (USSF) logo for the first time.
Image credit: Boeing

The U.S. military’s unique X-37B robotic space plane is being readied for its next flight, a mission that is expanding the vehicle’s past space portfolio of skills.

Right at the start, at launch that’s slated on December 7, the mission is distinctive.

For the first time, the Boeing-built craft is being hurled spaceward atop a SpaceX Falcon Heavy, “with a wide range of test and experimentation objectives,” explains a U.S. Space Force press statement.

The past flights of the vehicle made use of the Atlas V 501 launcher for the most part, although OTV-5 was placed in orbit via a SpaceX Falcon 9 Block 4 launcher.

Image credit: Boeing/Inside Outer Space Screengrab

New orbital regimes

The Department of the Air Force Rapid Capabilities Office (RCO), in partnership with the United States Space Force, is scheduled to launch the seventh mission of the X-37B Orbital Test Vehicle (OTV) on December 7 from Kennedy Space Center, Florida.

Designated USSF-52, the space plane tests include operating in new orbital regimes, experimenting with future space domain awareness technologies, and investigating the radiation effects on materials provided by NASA.


Expand the envelope

OTV-6 was the first mission to introduce a service module that expanded the capabilities of the spacecraft.
Image credit: Staff Sgt. Adam Shanks

“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.

Marco Langbroek is an astute satellite tracker based in the Netherlands. His view is that the combination of the US Air Force statement that the mission will include “operating the reusable space plane in new orbital regimes” with the choice of a Falcon Heavy booster, suggests that OTV-7 will go to a much higher orbit.

“The choice of a Falcon Heavy suggests a need for a more powerful rocket, and in the case of the X-37B this can only mean a much higher orbit,” Langbroek told Inside Outer Space, perhaps to geostationary orbit or at least a mission in a geostationary transfer orbit (GTO) that reaches GEO at apogee.

“That would be quite different from the previous X-37B OTV missions, which all went to the lower reaches of low Earth orbit,” Langbroek says.

Details: skimpy and classified

This upcoming X-37B Mission 7 is also known as OTV-7.

Since the X-37B first launched in 2010, Boeing has empowered the reusable spaceplane “with more capability, new technology, and pushed the boundaries of what’s possible with each ensuing mission,” the company points out.

The orbital test vehicle (OTV-6)  – after circling Earth for a record-setting 908 days — completed that mission with a successful landing at Kennedy Space Center on November 12, 2022.

OTV-6 after landing at Kennedy Space Center in Florida.
Image credit: Staff Sgt. Adam Shanks

As in previous missions, details of the soon-to-orbit OTV-7 in-space agenda are skimpy and classified.

The Space Force statement did note that the NASA experiment onboard will expose plant seeds to the harsh radiation environment of long-duration spaceflight. Known as “Seeds-2,” that investigation is paving the way for future crewed space missions.

Service module

As explained in the Air Force statement, the last space plane flight, X-37B Mission 6 (OTV-6), was the first mission to introduce a service module that expanded the capabilities of the spacecraft.

OTV-6 in-flight image. Image credit: Boeing/Inside Outer Space screengrab

That module hosted more experiments than any of the previous space plane missions. In the OTV-6 flight, the service module was detached in orbit from the space plane before its landing, necessary due to the aerodynamic forces seen by the X-37B vehicle upon re-entry. That service module was later disposed of “in compliance with best practices,” according to the Air Force.

OTV-6 PRAM experiment. Image credit: Boeing/Inside Outer Space screengrab

OTV-6 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.

OTV-6 in-space photo. Image credit: Boeing/Inside Outer Space screengrab

The X-37B Mission 6 also deployed FalconSat-8, a small satellite developed by the U.S. Air Force Academy and sponsored by the Air Force Research Laboratory.

The Air Force statement did note that the NASA experiment onboard will expose plant seeds to the harsh radiation environment of long-duration spaceflight. Known as “Seeds-2,” that investigation is paving the way for future crewed space missions.

OTV-6 return. Image credit: Boeing/Inside Outer Space screengrab


Chief of Space Operations, Gen. B. Chance Saltzman hailed the craft’s experiments as “groundbreaking,” adding that the X-37B “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.”

OTV-6 in-space photo. Image credit: Boeing/Inside Outer Space screengrab

The Director of the Department of Air Force Rapid Capabilities Office, William Bailey said: “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.”

Air Force X-37B space plane.
Image credit: Boeing

In Boeing-supplied information, the company says the vehicle is designed to operate in low-Earth orbit, 150 to 500 miles above the Earth.

Additionally, the vehicle makes use of several “first use in space” technologies including:

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

Flight roster

Here’s a listing of previous flights of the space plane:

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-6: Launched on May 17, 2020  and landed on November 12, 2022, circling Earth for 908 days.

This size chart shows how the Boeing-built X-37B robot space plane compares to NASA’s space shuttle, a larger version of the spacecraft called the X-37C and an Atlas 5 rocket.
Image: © AIAA/Grantz/Boeing/provided to Inside Outer Space via AIAA

Derivative plan

There are known to be at least two X-37B vehicles.

Curiously, back in late 2011, a technical paper popped up at a major aerospace conference. It outlined new plans for the spacecraft and a scaled-up version to support space station cargo deliveries or even haul astronauts into orbit.

An X-37B OTV and derivatives plan assessment sketched out a variety of scaled-up versions of the X-37B space plane.

What is not known, however, is whether such a plan advanced within Boeing or the Air Force.

Artistic boost

The U.S. military interest in use of space planes did get an artistic boost last month.

A painting was commissioned with artist Rick Herter titled “High Ground Intercept” – a depiction of space as a warfighting arena, now and into the future, as part of the Department of the Air Force Art Collection.

The artwork shows a futuristic U.S. space vehicle intercepting an adversary satellite, who in turn is positioning to disable a friendly satellite.

Space Operations Command reveals ‘futuristic’ official painting by artist Rick Herter: “High Ground Intercept” at the artwork’s unveiling on Oct. 20, 2023.
Image credit: Space Force/John Ayre

The tomorrow land look of the vehicle has historic links to the X-20 Dyna-Soar, the first U.S. space plane design, with its low-wing delta shape and vertical winglets. The bay doors of the intercept vehicle are opening as the space plane moves into position and prepares to defend the friendly satellite.

“Because of the highly classified nature of many space operations, SpOC requested that Herter rely on historic space planes and his own imagination,” explained Christopher Rumley, Space Operations Command (SpOC) command historian in rolling out the painting on October 20 at Peterson Space Force Base in Colorado.

“It was not an easy task, but Rick was able to fuse where we’ve been as a force with where we are going,” said Rumley in a SpOC statement.

Go to this informative Boeing video released last April, complete with head-banging-backed music, and look at the OTV-6 mission (thanks Mike Rose for calling my attention to this video) at:


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