The X-37B “Space Plane”: Still No Clear Mission, at a High Price

The X-37B is a reusable unmanned spacecraft developed by the US Air Force. The Union of Concerned Scientists asserts that the vehicle's design—specifically its ability to land like an airplane—imposes significant penalties in terms of mass, cost, and maneuverability. The report concludes that for every potential mission the X-37B could perform, including orbital inspection, reconnaissance, and sensor testing, there are more efficient and cheaper alternatives, such as lightweight disposable satellites or capsule-based recovery systems.

• The requirement for the X-37B to land on a runway adds several tons of extra mass due to the need for wings, landing gear, and heat-shielding, which increases launch costs and reduces orbital maneuverability.
• The X-37B is an inefficient platform for orbital inspection and reconnaissance compared to lightweight satellites; for example, using the X-37B to launch a MiTEx-style inspection satellite would increase the launch mass by 5,000 kg, a 20-fold increase.
• The vehicle's mass requirements hinder 'launch responsiveness' because it requires a heavy-lift Atlas V launcher rather than the smaller launchers used for quick-response payloads.
• The X-37B is poorly suited for replenishing satellite constellations or capturing satellites due to its limited cargo bay size, which is described as being roughly the size of a pickup truck bed.
• The document argues that the X-37B is not an effective space weapon; anti-satellite weapons would benefit from being smaller and stealthier, and ground-targeting weapons are more costly and less efficient when launched from orbit.
• The X-37B is not a viable method for rapid troop transport because it cannot carry people and would require specialized secure runways at its destination.

APA

Union of Concerned Scientists (2012). The X-37B “Space Plane”: Still No Clear Mission, at a High Price. https://www.ucs.org/sites/default/files/2019-09/X-37B-fact-sheet.pdf

Chicago

Union of Concerned Scientists. The X-37B “Space Plane”: Still No Clear Mission, at a High Price. 2012. https://www.ucs.org/sites/default/files/2019-09/X-37B-fact-sheet.pdf.

Wikipedia

{{cite report |author=Union of Concerned Scientists |title=The X-37B “Space Plane”: Still No Clear Mission, at a High Price |date=November 2012 |url=https://www.ucs.org/sites/default/files/2019-09/X-37B-fact-sheet.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{unionofconcernedscientists2012x37b, author = {{Union of Concerned Scientists}}, title = {{The X-37B “Space Plane”: Still No Clear Mission, at a High Price}}, institution = {Union of Concerned Scientists}, year = {2012}, month = nov, url = {https://www.ucs.org/sites/default/files/2019-09/X-37B-fact-sheet.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }