The very low-key X-37B Orbital Test Vehicle-6 (OTV-6) returned to Earth after a 908-day sortie when the U.S. Space Force’s unmanned, reusable spaceplane, successfully deorbited and landed at NASA’s Kennedy Space Center on 12 November at 05:22 a.m.
Constructed by Boeing and first launched on OTV-1 in April 2010, the aircraft’s sixth mission began atop an Atlas V rocket from Cape Canaveral Space Force Station in May 2020 and touched down at Space Florida– the Sunshine state’s “aerospace finance and development authority”– which operates the 15,000-foot long Launch and Landing Facility, one of the longest runways in the world, for both military and commercial purposes. It is the craft’s third landing at Space Florida.
Across its first five completed missions, the X-37B spent a total of 2,865 days in orbit with this one bringing that total to 3,773 days or 10.33 space years in orbit– not a bad record for an aircraft that has only been in service for 12 years. Weigh that against the 1,323 total days in space spent during NASA’s 135 Shuttle missions between April 1981 and July 2011– that tragically cost two Orbiter crews.
OTV -6 was the first mission to introduce a service module-a ring attached to the rear of the vehicle expanding the number of experiments that can be hosted during a mission. “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 service module successfully separated from the OTV before landing, which is a necessary activity due to the aerodynamic forces experienced by the X-37B vehicle upon re-entry. In the coming weeks, the service module will be disposed of in accordance with best practices. Secretary of the Air Force Frank Kendall said, “The deliberate manner in which we conduct onorbit operations-to include the service module disposal-speaks to the United States’ commitment to safe and responsible space practices, particularly as the issue of growing orbital debris threatens to impact global space operations.”
The OTV-6 mission hosted the Naval Research Laboratory’s Photovoltaic Radiofrequency Antenna Module. This experiment successfully harnessed solar rays outside of Earth’s atmosphere and aimed to transmit power to the ground in the form of radio frequency microwave energy. Additionally, the U.S. Air Force Academy’s FalconSat-8, developed in partnership with Air Force Research Laboratory, was successfully deployed in October 2021. FalconSat-8 remains in orbit, providing Academy cadets unique hands-on experience as space operators prior to entering active duty.
Multiple NASA experiments were deployed on OTV-6. The Materials Exposure and Technology Innovation in Space (METIS-2) included thermal control coatings, printed electronic materials, and candidate radiation shielding materials. METIS-1-which flew on OTV-5-consisted of similar sample plates mounted on the flight vehicle. NASA scientists will leverage data collected after the materials have spent 900+ days in orbit and compare observed effects to ground simulations, validating and improving the precision of space environment models.
Another NASA experiment aims to investigate the effect of long-duration space exposure on seeds. Scientists are interested in the seeds’ resistance and susceptibility to space environment-unique stresses, notably radiation. The seeds experiment will inform space crop production for future interplanetary missions and the establishment of permanently inhabited bases in space.