X‑37B spaceplane tests fuel-saving maneuvers in orbit
The unmanned X-37B spaceplane, operated by the United States Air Force, has been in orbit for over a year. Although the tests related to its mission are classified, the Pentagon has indicated that it is studying the possibilities of aerodynamic braking. This approach could save fuel and enable dynamic maneuvers, including combat, in space.
The X-37B is a small, unmanned spaceplane built by Boeing. This model, operational since 2010 after tests with the earlier X-37A variant, has conducted several classified missions in Earth's orbit.
The vehicle measures just under 9 metres in length and has tiny wings with a wingspan of about 4.5 metres. Weighing approximately 5,000 kilograms, the spaceplane features a payload bay slightly over two cubic metres long.
The X-37B spaceplane is notable for the duration it can remain in space. It stayed in orbit for 908 days during a record flight, even though the official specification initially claimed a 270-day operational autonomy. It is now clear that this was inaccurate, as the current X-37B mission has lasted for over a year. What, then, is the spaceplane doing in orbit for so long?
Aerodynamic braking in space
One key task involves testing aerodynamic braking possibilities. This process utilizes the resistance generated by Earth's atmosphere at high altitudes, even above the typical boundary of space.
Although the atmospheric gases at these altitudes are very sparse, they provide enough aerodynamic drag to be useful. For the X-37B, this enables a quick orbital shift to a lower orbit without using the engine, thus conserving precious fuel.
Dynamic space operations
The official purpose of these tests is to explore the option of quickly disposing of the mission module's carrier. Previously, once released at a significant orbital height, it became space debris and orbited Earth for decades.
Current guidelines from NASA recommend that space debris should be left in orbit for no more than 25 years. However, the current X-37B tests aim to cut this time to five years. During this period, due to atmospheric resistance, the mission module is expected to lower its altitude enough to burn up in the atmosphere.
Aside from the stated purpose of these tests, experts also speculate about the potential for these operations to be used for combat in space. This is aligned with what the Pentagon refers to as "dynamic space operations," which potentially allow maneuvers such as inspecting or neutralizing hostile satellites.
