The Boeing X-37B stands out as a reusable robotic spacecraft designed for orbital missions. Operated by the United States Space Force in partnership with the Air Force Rapid Capabilities Office, this uncrewed vehicle tests new space technologies. It resembles a smaller version of the retired Space Shuttle, but it flies without a crew and handles tasks autonomously. Over the years, the X-37B has proven its value by staying in orbit for extended periods, carrying experiments, and returning to Earth for reuse. Missions often involve classified activities, yet they contribute to advancements in space operations.
Development and History
The X-37 program began in 1999 as a NASA project, with Boeing leading the design. Early work focused on creating an orbital vehicle to test reusable space systems. By 2004, the project shifted to the Department of Defense, becoming classified under DARPA. The Air Force took over in 2006, developing the X-37B variant for military applications.
Initial tests involved drop flights from aircraft to check gliding and landing. The first orbital mission launched in 2010, marking the start of operational use. Control passed to the Space Force in 2020, aligning with broader military space efforts. Seven missions have flown so far, each building on the last to refine capabilities.
Design Features
The X-37B measures about 29 feet long, with a wingspan of nearly 15 feet and a height of around 9.5 feet. It weighs up to 11,000 pounds at launch. Solar panels provide power, unfolding in orbit to charge batteries. A small payload bay, roughly 7 feet by 4 feet, holds experiments or small satellites.
The spacecraft launches vertically on rockets like the Atlas V or Falcon 9. In space, it maneuvers using a propulsion system fueled by hypergolic propellants. For return, it reenters the atmosphere at high speeds, up to Mach 25, protected by heat-resistant tiles. It lands horizontally on runways, much like an airplane, without human intervention. This design allows multiple uses, reducing costs compared to one-time spacecraft.
Past Missions
The X-37B has completed seven orbital test vehicle missions, each lasting longer than the previous ones in many cases. The first, OTV-1, launched in April 2010 on an Atlas V from Cape Canaveral and spent 224 days in orbit before landing at Vandenberg Space Force Base. It tested basic systems and achieved the first autonomous orbital landing by a U.S. vehicle.
OTV-2 followed in March 2011, using the second X-37B airframe, and remained aloft for 468 days. It expanded on sensor and system evaluations. OTV-3, starting in December 2012, reused the first airframe for 674 days, focusing on endurance.
Later missions grew more ambitious. OTV-4 launched in May 2015 and lasted 717 days, testing electric propulsion and materials for NASA. It landed at the Kennedy Space Center shuttle runway for the first time. OTV-5, from September 2017, set a record at 780 days, experimenting with space domain awareness.
OTV-6, in May 2020, stayed up for 908 days—the longest yet—and deployed a small satellite while testing power beaming technology. The most recent, OTV-7, launched in December 2023 on a Falcon Heavy and landed in March 2025 after about 435 days. It conducted aerobraking maneuvers to change orbits efficiently and studied radiation effects on plant seeds.
These flights have totaled over 4,200 days in space, demonstrating the vehicle’s reliability.
The Upcoming OTV-8 Mission
The eighth mission, OTV-8, is scheduled to launch no earlier than August 21, 2025, from Kennedy Space Center in Florida. A SpaceX Falcon 9 rocket will carry it into orbit. This flight continues the program’s tradition of testing innovative technologies in a real space environment.
Preparation involves loading payloads at secure facilities, with technicians in protective gear handling the fuels. Once in orbit, the X-37B will operate independently, performing maneuvers as needed. The mission’s duration remains undisclosed, but past patterns suggest it could last several months or longer. Landing will likely occur at one of the usual sites, such as Kennedy or Vandenberg.
Experiments on Board
OTV-8 will host several tests to advance space capabilities. One key experiment involves inter-satellite laser communications. This technology uses lasers to send data between satellites in low Earth orbit at high speeds. It supports better command and control for networks of satellites, especially in military contexts where secure, fast links matter.
Another highlight is a quantum navigation system. This setup cools atoms to near absolute zero, turning them into waves. Lasers then split and recombine these waves to detect tiny changes in motion, like acceleration or rotation. The system tracks position accurately without external signals. It offers advantages in environments where GPS fails, such as deep space or jammed areas, and avoids drift over time since atoms stay consistent.
These experiments build on previous ones, like aerobraking for orbit adjustments and solar power transmission tested in earlier missions.
Importance for Space Operations
The X-37B program enhances reusable spacecraft options for the military. Its ability to deploy and retrieve payloads quickly provides flexibility not found in traditional satellites. Long-duration flights allow extended testing of equipment under space conditions, informing future designs.
By operating in various orbits, the vehicle gathers data on space weather, radiation, and other factors affecting satellites. Results from these missions influence broader space strategies, including domain awareness and resilient communications. As space activities increase, such platforms help maintain advantages in technology and operations.
Summary
The X-37B represents a key asset in reusable space technology, with a history of successful missions that have pushed boundaries in endurance and experimentation. The upcoming OTV-8 launch on August 21, 2025, will introduce tests in laser communications and quantum navigation, potentially shaping future navigation and data transfer in space. Through these efforts, the program continues to support evolving needs in orbital operations.
