The X-37B returned to Earth on Saturday after a record 902 days in space, beating its previous stay in space by 127 days.
The end of OTV6 was marked by the landing of the Boeing-built space plane at NASA's Kennedy Space Center Shuttle Landing Facility in Florida.
The X-37B is about a quarter the length of NASA's now-decommissioned space shuttle but it is similar in appearance.
This mission wasn't the only one. It was the first X-37B flight to carry a ring to increase the number of experiments that can be hosted during a mission. The module was released from the space plane before landing to maintain the vehicle's aerodynamic design for safe entry into Earth's atmosphere.
One of the experiments on the most recent flight was set up by the Naval Research Laboratory and focused on converting solar power into microwaves.
The effects of radiation on seeds were examined in a third investigation. The establishment of permanently inhabited bases in space could be aided by discoveries.
Air Force Lieutenant Colonel Joseph Fritschen said that the X-37B continues to push the boundaries of experimentation. The ability to conduct on-orbit experiments and bring them home safely has proven valuable for the Department of the Air Force. More experiments were hosted because of the addition of the service module on OTV.
The primary objectives of the X-37B are twofold, according to the USAF.
The timing of the next mission has not been announced.
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