It was May 2015 when the Boeing-built X-37B spaceplane took off on an Atlas 5 rocket for its 718-day secret mission that ended this Sunday at the Kennedy Space Center. The unmanned orbiter is equipped with a payload bay, a solar power boom and sophisticated computer control systems, but its exact purpose while on orbit is still unknown outside the US military.
It was around 8:00 AM when sonic booms were reported in central Florida, spanning from Tampa to Fort Myers. A few minutes later, the US Air Force released the following tweet acknowledging the X-37B"s successful landing:
At least two X-37B spaceplanes, which have already flown four secret missions including this one, are known to exist, according to CBS News. They were both built by Boeing for the US Air Force in two former shuttle processing hangars acquired and modified by the company to handle the secret spacecraft. Also, this is the first such mission to land in Florida, while the previous three have landed at Vandenberg Air Force Base, in California.
Currently, only two experiments carried out by the spaceplane were acknowledged by the US Air Force: a materials science project for NASA; and an Aerojet Rocketdyne Hall-effect thruster test. According to Lt. Col. Ron Fehlen, the X-37B program manager:
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.
The next launch of a X-37B spaceplane is expected for later this year.
Source: CBS News