Anti-Satellite Weapons

Anti-satellite weapons, or ASAT weapons, are capabilities designed to disrupt, degrade, damage or destroy satellites and the systems supporting them. They may attack the spacecraft itself, its ground infrastructure or the communication links between them through kinetic, directed-energy, electronic or cyber means.

Principal technological categories

Counterspace capabilities are classified by how they interfere with a space system and whether they physically damage it.

• Kinetic-physical weapons destroy or damage objects through impact. They include direct-ascent interceptors and co-orbital weapons placed into orbit near a target.
• Non-kinetic physical weapons use directed energy, such as lasers or high-powered microwaves, to dazzle sensors or damage components without collision.
• Electronic attacks jam or spoof radio-frequency links used for satellite command, telemetry, navigation or communications.
• Cyberattacks target software, data, computers or networks in the satellite, ground segment or communications link, potentially disrupting operations or control.

How direct-ascent interception works

A direct-ascent weapon is launched from Earth and strikes a satellite without first entering orbit near it.

• Ground sensors calculate the satellite's orbit and a future intercept point; a rocket booster then launches from land, sea or air toward that point.
• Guidance updates and an onboard seeker steer the kill vehicle during terminal approach. The interceptor need not chase the satellite around an entire orbit.
• In a hit-to-kill attack, relative velocity supplies enough kinetic energy to rupture the satellite without an explosive warhead, destroying power, communications, sensors, payload or attitude control.

Debris, strategy and international law

Kinetic destruction can create orbital debris that threatens other spacecraft. Debris may persist until atmospheric drag removes it, and persistence generally increases with altitude.

• The Outer Space Treaty, 1967 does not comprehensively prohibit conventional anti-satellite weapons.
• Article IV prohibits placing nuclear weapons or other weapons of mass destruction in orbit and restricts military activities on celestial bodies.
• Article IX requires due regard for other states' activities and consultations where an activity may cause potentially harmful interference; these duties make restraint, verification and debris mitigation central governance concerns.