A new video lays out the basics of what the Air Force's robotic X-37B space plane is doing on its latest mystery mission, which lifted off last week.

Most aspects of X-37B missions are classified, so the new video — which was produced by Boeing, the vehicle's maker — doesn't go into detail. But it does give a sense of why the Air Force values the reusable space plane so highly.

"The X-37B testbed platform is unique because we can tailor our missions to specific user needs and return experiments back for post-flight inspection," Ken Torok, director of experimental systems at Boeing, says in the video.

The video was released last Thursday (Sept. 7), the day that a SpaceX Falcon 9 rocket launched an X-37B on the program’s Orbital Test Vehicle (OTV-5) mission.

Flights of the craft in the past have repeatedly broken the program's own duration record.

The first OTV mission 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.

The OTV-3 mission wrapped up nearly 675 days in orbit when it landed on Oct. 17, 2014.

On May 7, 2017, OTV-4 landed at NASA’s Kennedy Space Center Shuttle Landing Facility — a first for the program, as all previous missions ended with a tarmac touchdown at Vandenberg Air Force Base in California. The X-37B conducted on-orbit experiments for 718 days during OTV-4, extending the total number of days spent on orbit for the OTV program to 2,085 days.

The Air Force is known to own two X-37B vehicles, which constitute the space plane "fleet."

Appearing like a miniature version of NASA’s now-retired space shuttle orbiter, the reusable 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 space drone has a payload bay about the size of a pickup truck bed that can be outfitted with a robotic arm. The X-37B has a launch weight of 11,000 lbs. (4,990 kilograms) and is powered on orbit by a solar cell-laden array.

To view the just-released video, go to: https://www.youtube.com/watch?v=u-7VNf7DCY8

Leonard David is author of "Mars: Our Future on the Red Planet," published by National Geographic. The book is a companion to the National Geographic Channel series "Mars." A longtime writer for Space.com, David has been reporting on the space industry for more than five decades. Follow us @SpacedotcomFacebook or Google+. This version of this story was posted on Space.com.