Secretive space plane X-37B to test ‘first of a kind’ maneuvers for shifting orbits

WASHINGTON — The Space Force’s  X-37B experimental spacecraft is about to begin taking a series of “novel maneuvers” to safely dispose of its service module that carries extra payloads, the service announced today in a rare public statement about the activities of the mysterious spaceplane.

“The X-37B Orbital Test Vehicle (OTV-7) will begin executing a series of novel maneuvers, called aerobraking, to change its orbit around Earth and safely dispose of its service module components in accordance with recognized standards for space debris mitigation,” the Space Force said.

Aerobraking uses the drag of Earth’s atmosphere to slow a spacecraft and allow it to move into a lower orbit without relying solely on firing its propulsion engines, in essence making a series of orbits that look like a spiral to achieve a lower orbit. (Think about those spiral wishing wells that used to populate shopping mall corridors, where a coin put on the top surface spirals its way down into a small hole and plonks into a collection box.)

The maneuver “enables the spacecraft to change orbits while expending minimal fuel,” the Space Force release said.

The X-37B OTV-7 was launched into highly elliptical orbit (HEO) on Dec. 28, 2023 to conduct a number of tests, described by the Space Force at the time as including “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.” Earlier missions took place in low Earth orbit (LEO).

“Once the aerobrake maneuver is complete, the X-37B will resume its test and experimentation objectives until they are accomplished,” the Space Force said.

Asked about the specific trajectory of the maneuvers, a Space Force spokesperson declined to give details.

To safely deorbit, however, the service module would need to be placed in LEO at a low enough altitude to allow it to eventually fall into the Earth’s atmosphere due to drag. Current US debris mitigation standards call for defunct spacecraft in lower orbits to be stationed where they will deorbit within 25 years, although the Federal Communications Commission is requiring companies to reduce that time to five years.

And aerobraking would allow the spaceplane to efficiently move from HEO to a stable LEO position to eject the service module, which is attached to the back of the X-37B to provide more cargo space. The module would then burn up in the atmosphere. In its previous mission, the reusable space plane simply jettisoned the module as itself began its de-orbit maneuvers to land safely.

Thus, it is the maneuvering that is the new element of the spaceplane’s recent activities.

“This first of a kind maneuver from the X-37B is an incredibly important milestone for the United States Space Force as we seek to expand our aptitude and ability to perform in this challenging domain,” said Chief of Space Operations Gen. Chance Saltzman in the service press release.

US Space Command has been clamoring for new technology to enable “dynamic space operations,” which include “sustained” maneuvering that doesn’t eat up fuel to allow US military spacecraft and satellites to outrun suspect adversary satellites — or potentially be able to chase those suspect birds down both to assess any threats they pose and possibly take action to neutralize them.

The Defense Department has been coy about X-37B’s missions, capabilities and whereabouts when on orbit since taking the space plane program over from NASA in 2006 — and the robotic craft long has been the subject of speculation, including by Russia and China, that it in reality is an on-orbit weapons platform.

According to Secure World Foundation’s latest “Global Counterspace Capabilities” report [PDF], that speculation was fueled in recent years by the October 2023 release of the Space Force’s first official painting, which showed a military space plane described only as a “futuristic intercept vehicle” getting ready to engage with an enemy satellite. At the time, the service said the painting was strictly a result of the artist’s imagination.

Low-cost maneuvers such as aerobraking could be one method of doing the job of approaching adversary sats — although rather slowly.

While the X-37B program has been managed since 2010 by the Air Force Rapid Capabilities Office, Space Force’s Delta 9 now responsible for oversight of X-37B’s on-orbit operations.

Delta 9, according to the service’s website, conducts “protect and defend operations and providing national decision authorities with response options to deter and, when necessary, defeat orbital threats” and preparing Guardians for “orbital warfare.”