Washington: An unmanned US space plane has set its new endurance record after spending 2.5 years in orbit before landing on Saturday, the developer of the spacecraft, Boeing, said.

"The Boeing-built X-37B Orbital Test Vehicle (OTV) set a new endurance record after spending 908 days in orbit before landing at NASA's Kennedy Space Centre in Florida at 5:22 a.m. ET, November 12, 2022. This surpasses its previous record of 780 days in-orbit," the company said in a statement.

The solar-powered spacecraft resembles the retired space shuttle, but is several times smaller, about 9 meters (29 feet) long. Its five previous missions in orbit lasted from 224 to 780 days.

"Autonomous orbital test vehicle spent 908 days on orbit before landing at NASA's Kennedy Space Center," the company said.

This time, the spacecraft hosted a service module, which conducted experiments for the US Naval Research Laboratory, the US Air Force Academy and others, the company said.

With the successful completion of its sixth mission the reusable spaceplane has now flown over 1.3 billion miles and spent a total of 3,774 days in space where it conducts experiments for government and industry partners with the ability to return them to Earth for evaluation.

For the first time, the vehicle carried a service module to augment the number of payloads it can haul. The module separated from the Orbital Test Vehicle (OTV) prior to de-orbiting ensuring a safe and successful landing.

"This mission highlights the Space Force's focus on collaboration in space exploration and expanding low-cost access to space for our partners, within and outside of the Department of the Air Force (DAF)," said Gen. Chance Saltzman, Chief of Space Operations.

The sixth mission was launched atop a United Launch Alliance Atlas V rocket from Cape Canaveral Space Force Station in May 2020.

"Hosted experiments included a solar energy experiment designed by the Naval Research Lab, as well as a satellite designed and built by cadets at the U.S. Air Force Academy in partnership with the Air Force Research Laboratory. The satellite, dubbed FalconSat-8, was successfully deployed in October 2021 and remains on orbit today," the company said.

"This mission also hosted multiple NASA experiments including the Materials Exposure and Technology Innovation in Space (METIS-2), which evaluated the effects of space exposure on various materials to validate and improve the precision of space environment models. This was the second flight for this type of experiment," it added.

Mission 6 also hosted a NASA experiment to evaluate the effects of long-duration space exposure on seeds. This experiment informs research aimed at future interplanetary missions and the establishment of permanent bases in space.