From The Editor | December 22, 2022

The Secret (Well, OK … Not Too Secret) Experiments On Board X-37B

John Oncea

By John Oncea, Editor


I love space. I don’t pretend to understand it, but I’m constantly amazed at the natural wonders that are out there. Turns out, some of the wonders of space aren’t natural. For instance, there’s the Air Force’s X-37B Orbital Test Vehicle, the newest and most advanced re-entry spacecraft.

According to the U.S. Air Force’s fact sheet, X-37B is based on NASA’s X-37 design and is designed for vertical launch to low Earth orbit altitudes where it can perform long-duration space technology experimentation and testing. The primary objectives of the X-37B are twofold; reusable spacecraft technologies for America’s future in space and operating experiments that can be returned to, and examined, on Earth.

While the X-37B is a marvel of modern engineering, what’s got my interest are the scientific experiments being conducted onboard. The same fact sheet linked to above indicates that the “technologies being tested in the program include advanced guidance, navigation and control, thermal protection systems, avionics, high-temperature structures and seals, conformal reusable insulation, lightweight electromechanical flight systems, advanced propulsion systems, advanced materials, and autonomous orbital flight, reentry, and landing.”

Recently, the X-37B concluded its sixth successful mission (OTV-6), landing at NASA’s Kennedy Space Center Shuttle Landing Facility. The Space Force release notes OTV -6 was the first mission to introduce a service module-a ring attached to the rear of the vehicle expanding the number of experiments that can be hosted during a mission.

“The X-37B continues to push the boundaries of experimentation, enabled by an elite government and industry team behind the scenes,” said Lt. Col. Joseph Fritschen, DAF Rapid Capabilities Office’s X-37B Program Director. “The ability to conduct on-orbit experiments and bring them home safely for in-depth analysis on the ground has proven valuable for the Department of the Air Force and scientific community. The addition of the service module on OTV-6 allowed us to host more experiments than ever before.”

But beyond that, according to NPR, “Not much is known about the X-37B's missions. Officials have released scant information about a few experiments that took place aboard the latest flight.”

One of the known experiments conducted was the Naval Research Laboratory's Photovoltaic Radiofrequency Antenna Module. This experiment successfully harnessed solar rays outside of Earth's atmosphere and aimed to transmit power to the ground in the form of radio frequency microwave energy.

In addition, multiple NASA experiments were deployed on OTV-6. The Materials Exposure and Technology Innovation in Space (METIS-2) included thermal control coatings, printed electronic materials, and candidate radiation shielding materials. METIS-1-which flew on OTV-5 – consisted of similar sample plates mounted on the flight vehicle. NASA scientists will leverage data collected after the materials have spent 908 days in orbit and compare observed effects to ground simulations, validating and improving the precision of space environment models.

Another confirmed experiment, according to Impact Lab, was FalconSat-8, a microsatellite designed and built by cadets at the U.S. Air Force Academy. “The space plane released the satellite into orbit back in May 2020, where it remains in operation today,” writes Impact Lab. “FalconSat-8 was developed to test a novel electromagnetic propulsion system and also sports low-weight antenna technology.

“Alongside this, it is also carrying three other technological experiments. These include a special form of cabling with carbon nanotube braiding and a flywheel capable of storing and releasing energy.”

Also on board was SkyPad, a device capable of image processing, star tracking, and orbit determination. It was specially developed for low size, weight, and power requirements, but was built from off-the-shelf components.

Grey Dynamics writes, “Given the classified nature of early OTV missions, speculation is abundant about the X-37B’s purpose and capabilities. Keep in mind that almost all of these are unconfirmed or theoretical.” Grey Dynamics speculates that these capabilities could deployment of unregistered spy satellites, delivery of nuclear or conventional weapons to targets on Earth, delivery of anti-satellite weapons, spying on rival space stations, covert orbital reconnaissance, and as a testbed for future spy satellite technology.

Despite the speculation, government officials insist the X-37B is simply a testbed for emerging technologies and experiments such as an ion thruster, which uses significantly less fuel than chemical thrusters and may revolutionize space travel.