Secret Military Space Shuttle Lands in Florida With a Sonic Boom

Locals were shocked at a sonic boom that rang across Central Florida -- and even beyond -- on early Sunday morning, which marked the end of a secret military space mission that began way back in May 2015.

According to a report from Orlando Sentinel, the unmanned X-37B mini space shuttle landed at the Kennedy Space Center after a total of 718 days in orbit. The X-37B Orbital Test Vehicle mission 4 (OTV-4) was the fourth for the 29-foot-long, 11,000-pound mini-shuttle, but its first landing in Florida.

The reason why the spacecraft spent all that time out in space is a closely guarded secret, however. There are experts who believe that the shuttle is carrying intelligence-gathering equipment, while the military revealed that it was "an experimental test program to demonstrate technologies for a reliable, reusable, unmanned space test platform for the U.S. Air Force."

The OTV program has already spent a total of 2,085 days in orbit, according to a report from the Air Force. The x-37B mini shuittle is considered the newest and most advanced re-entry spacecraft, and the program is able to perform risk reduction, experimentation and concept of operations development for reusable space vehicle technologies.

"The landing of OTV-4 marks another success for the X-37B program and the nation," program manager Lt. Col. Ron Fehlen explained. "This mission once again set an on-orbit endurance record and marks the vehicle's first landing in the state of Florida. We are incredibly pleased with the performance of the space vehicle and are excited about the data gathered to support the scientific and space communities. We are extremely proud of the dedication and hard work by the entire team."

The fifth X-37B mission will launch from the Cape Canaveral Air Force Station in Florida later this year.