Post-landing of OTV-5 at NASA’s Kennedy Space Center Shuttle Landing Facility.
Courtesy Photo 45th Space Wing Public Affairs


The classified U.S. Air Force X-37B robotic space plane program has chalked up a new milestone.

Post-landing technicians tend OTV-5 at NASA’s Kennedy Space Center Shuttle Landing Facility.
Courtesy Photo 45th Space Wing Public Affairs

Touching down at NASA’s Kennedy Space Center Shuttle Landing Facility on October 27th, the Orbital Test Vehicle-5 (OTV-5) conducted on-orbit experiments for 780 days during its mission, breaking the program’s own record by being in orbit for more than two years.

The total number of days spent on-orbit for the entire test vehicle program is now 2,865 days.

Pre-OTV-5 landing Boeing handout describes X-37B program.
Credit: Boeing

Next launch

The Air Force is preparing to launch the sixth X-37B mission from Cape Canaveral Air Force Station, Florida in 2020.

Built by Boeing and managed by the Air Force Rapid Capabilities Office, the X-37B program performs risk reduction, experimentation and concept of operations development for reusable space vehicle technologies.

“The X-37B continues to demonstrate the importance of a reusable spaceplane,” said Secretary of the Air Force Barbara Barrett in an Air Force press statement. “Each successive mission advances our nation’s space capabilities.”

X-37B handout.
Credit: Boeing

Milestone setting

Each X-37B/OTV mission has set a new flight-duration record for the program:

OTV-1 began April 22, 2010, and concluded on Dec. 3, 2010, after 224 days in orbit.

OTV-2 began March 5, 2011, and concluded on June 16, 2012, after 468 days on orbit.

OTV-3 chalked up nearly 675 days in orbit before finally coming down on Oct. 17, 2014.

OTV-4 flew for nearly 718 days during its mission. It was launched in May 2015 and landed at the Kennedy Space Center in May 2017.

OTV-5 circled Earth for 780 days after launch on Sept. 7, 2017, coming to a tarmac touchdown at Kennedy Space Center on October 27, 2019.

Credit: Boeing/Inside Outer Space Screengrab


Looking like a miniature version of NASA’s now-retired space shuttle orbiter, the military space plane is 29 feet (8.8 meters) long and 9.6 feet (2.9 m) tall, with a wingspan of nearly 15 feet (4.6 m).

The X-37B space plane has a payload bay of 7 feet (2.1 meters) by 4 feet (1.2 meters), a bay that can be outfitted with a robotic arm. X-37B has a launch weight of 11,000 lbs. (4,990 kilograms) and is powered on orbit by gallium-arsenide solar cells with lithium-ion batteries.

Asets-II payload logo.
Credit: AFRL

Payload partners

When OTV-5 was launched, the Air Force noted that the mission was launched into, and would be landed from, a higher inclination orbit than prior missions to further expand the X-37B’s orbital envelope.

On this latest clandestine mission of the space plane, all that’s known according to Air Force officials is that one payload flying on OTV-5 was the Advanced Structurally Embedded Thermal Spreader, or ASETS-II.

Developed by the U.S. Air Force Research Laboratory (AFRL), this cargo was to test experimental electronics and oscillating heat pipes for long duration stints in the space environment.

According to AFRL, the payload’s three primary science objectives of ASETS-II were to measure the initial on-orbit thermal performance, to measure long duration thermal performance, and to assess any lifetime degradation.

Randy Walden, Air Force Rapid Capabilities Office director adds that the X37B/OTV program continues to push the envelope as the world’s only reusable space vehicle. The OTV-5 mission “successfully completed all mission objectives,” Walden said, hosting Air Force Research Laboratory experiments, among others, “as well as providing a ride for small satellites.”

Whether or not the spaceplane deployed mini-satellites is not clear, with satellite watchers noting that, if so, they are not catalogued by the Air Force.

Skywatcher and satellite tracker, Ralf Vandebergh of the Netherlands, imaged the OTV-5 spaceplane flying overhead.
Credit: Ralf Vandebergh


Drives them nuts

It is always touch and go regarding what can/cannot be said about the spaceplane program.

However, former Secretary of the Air Force Heather Wilson laid out some basic details of the X-37B’s mission during an appearance earlier this year at the Aspen Security Forum.

“The Air Force has acknowledged that we own a space plane, the X-37 – looks like a small version of the shuttle, but it’s unmanned. One of the things that’s fascinating about that space plane is that it can do an orbit that looks like an egg, and when it’s close to the Earth it is close enough to the atmosphere to turn where it is, which means our adversaries don’t know – and that happens on the far side of the Earth from our adversaries – they don’t know where it’s going to come up next, and we know that drives them nuts,” Wilson said.

Following OTV-5’s landing, Air Force Chief of Staff Gen. David L. Goldfein, said: “The sky is no longer the limit for the Air Force and, if Congress approves, the U.S. Space Force.”

Go to this Air Force landing video clip at:

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