X-37B after landing photos.

Certainly the coolest UAS on the block at the minute, Air Force Space Command Photos: The X-37B sits on the Vandenberg Air Force base runway during post-landing operations Dec. 3. Personnel in SCAPE (Self-contained atmospheric protective ensemble) suits conduct initial checks on the vehicle and ensuring the area is safe.

Wikipedia reports :-

The X-37 is expected to operate in a velocity range of up to Mach 25 on reentry. Among the technologies to be demonstrated with the X-37 are improved thermal protection systems, avionics, the autonomous guidance system, and an advanced airframe. The vehicle is powered by a Rocketdyne AR2-3 engine.The AR2-3 was the human-rated rocket powerplant for the dual-power NF-104Aastronaut training vehicle and was given a new flight certification for use on the X-37 with hydrogen peroxide/JP-8 propellants. The X-37B now uses a hydrazine monopropellant rocket.

The X-37 has a payload bay available for experiments and other space payloads. It features thermal protection systems that are improved from previous generations of spacecraft. The thermal protection system uses improved silica ceramic tiles