spaceSpace and Physics

US Space Force's Mysterious X-37B Plane Sets Yet Another Record For Longest Time In Orbit

It's probably not a spy plane. Probably.


Dr. Katie Spalding

Katie has a PhD in maths, specializing in the intersection of dynamical systems and number theory.

Freelance Writer

The X-37B space plane on a runway looking majestic
The space plane (not pictured: space) Image Credit: Boeing

The US Space Force's robotic X-37B space plane (a very sci-fi collection of words) has set two new records. On July 7, it broke its own previous record for time spent in Earth orbit by one day. On July 8, it presumably did the same thing again.

The X-37B, an uncrewed and reusable vehicle billed by Boeing as “one of the world’s newest and most advanced re-entry spacecraft,” is currently on its sixth mission, known as Orbital Test Vehicle-6 or OTV-6. It launched on May 17, 2020, meaning that as of July 7, it has been in space for 781 days non-stop.


The previous record of 780 days, was achieved in August 2019 – every one of the six flights has been a record-breaker. The first, launched in 2010, lasted 224 days in orbit before coming back to Earth and landing at Vandenberg Space Force Base, California; the next flight more than doubled that. The third mission lasted over 674 days; the fourth, launched in 2015, spent 718 days in orbit.

The Boeing spacecraft boasts quite a few features that have marked a “first use” in space, the company notes, including automated de-orbit and landing functions; all-electro-mechanical actuated flight controls and brakes; plus cutting-edge materials used in its construction. 

It’s about one-fourth the size of the Space Shuttle, and its design “combines the best of aircraft and spacecraft into an affordable system that is easy to operate and maintain.”

Continuing the X-37B’s long history of secrecy, OTV-6 is reportedly carrying several classified payloads, reports. Not all of the on-board deliveries are secret, though: one of the success stories of the OTV-6 mission has been the US Naval Research Laboratory's Photovoltaic Radio-frequency Antenna Module, or PRAM – a project aiming to harvest solar energy from space to use on Earth.


“The analysis to this point has shown that [PRAM] has performed as well in orbit and even in some cases exceeded our pre-launch laboratory testing,” Chris DePuma, PRAM program manager said in a statement last year

Receiving the first data packages from the X-37B “confirmed all our hard work had paid off,” he said: “PRAM was working in orbit, and delivering valuable data to advance space solar and power beaming research.” 

Also hitching a ride on OTV-6 is the U.S. Air Force Academy-designed FalconSat-8 satellite – the first satellite built and designed by cadets to enter space aboard the X-37B. 

“FalconSAT-8 is an educational platform for cadets,” said Lt. Col. Dan Showalter, assistant astronautics professor at the Academy. “We perform technology demonstrations for the Air Force.”


That’s not the only reason FalconSat-8 is up there: it also carries five experimental payloads, plus two NASA experiments investigating the effects of radiation on plant seeds. 

All this mystery around the spacecraft has led to some more conspiratorially-minded commenters suggesting that the X-37B may be a tool for covert ops – or even a weapon. However, experts have pointed out a few holes in that idea: at  8.8 meters (29 feet) in length and 2.9 meters (9.5 feet) tall, with a wingspan slightly under 15 feet (4.6 m) and a launch weight of 4,990 kilograms (11,000 pounds), the vehicle is both too small and too unwieldy to be an effective weapon.

“It can be tracked, so it's going to be hard for it to sneak up on anything,” former Air Force orbital analyst Brian Weeden told back when OTV-6 first launched. “And when it comes down itself, it's a very ungainly, slow-moving glider.”


spaceSpace and Physics
  • tag
  • space,

  • military,

  • aviation,

  • planes,

  • Space Force