Home Library Glossary Debris & Space Safety ASAT
🛡️ Debris & Space Safety

Anti-Satellite Weapon (ASAT)

Also known as: ASAT, Anti-Satellite Missile, Killer Satellite, Anti-Satellite Test

📘 Definition
Anti-satellite weapons encompass a range of technologies designed to deny, disrupt, or destroy space-based assets. Direct-ascent kinetic-kill vehicles are ground-launched missiles that physically collide with a target satellite at orbital velocities, shattering it into thousands of trackable and untrackable fragments. Other ASAT methods include co-orbital interceptors (satellites that manoeuvre alongside a target), ground-based lasers (dazzling or blinding sensors), cyber attacks on ground control links, and electronic jamming. Four nations have demonstrated kinetic-kill ASAT capability: the United States, Russia, China, and India. The resulting debris from these tests constitutes a significant and long-lasting threat to the orbital environment.
US, Russia, China, India
Known ASAT Nations
Fengyun-1C (2007) — 3,500+ fragments
Worst Debris Event
Russia, Kosmos-1408 (Nov 2021)
Most Recent Kinetic Test
Self-imposed ban since April 2022
US Moratorium

Understanding ASAT

Major ASAT Tests

YearNationTargetDebris CreatedStatus
2007ChinaFengyun-1C (865 km)3,500+ trackedMost fragments still in orbit
2008USAUSA-193 (250 km)174 trackedAll decayed within months (low altitude)
2019IndiaMicrosat-R (283 km)400 trackedMost decayed; some boosted higher
2021RussiaKosmos-1408 (480 km)1,500+ trackedThreatened ISS crew; decaying slowly

Why ASATs Threaten Everyone

Unlike terrestrial weapons, the consequences of a kinetic ASAT test affect all spacefaring nations. Debris from the Fengyun-1C test in 2007 spread across a wide altitude band and will remain in orbit for centuries. Each fragment becomes a potential impactor that can trigger further collisions — feeding the Kessler syndrome chain reaction. Even nations that did not conduct the test must now manoeuvre their satellites to avoid the resulting debris field.

Non-Kinetic Alternatives

Modern ASAT development increasingly focuses on reversible, non-debris-generating methods: GPS spoofing and jamming to deny navigation; cyber intrusion into satellite control links; ground-based lasers that dazzle optical sensors; and electronic warfare that overwhelms communication frequencies. These methods are harder to attribute and do not create lasting debris, making them strategically attractive but also harder to deter.

🛰️ Track ASAT Debris
See debris clouds from known ASAT tests on Orbital Radar's debris map.
Open Debris Map →
📖 Learn More

Frequently Asked Questions

The Outer Space Treaty does not explicitly ban ASAT weapons, though it prohibits placing weapons of mass destruction in orbit. There is growing international momentum toward a norm against destructive kinetic ASAT testing — the United States declared a voluntary moratorium in 2022, and the UN General Assembly has passed resolutions urging others to follow.
China's 2007 destruction of the Fengyun-1C weather satellite at 865 km altitude generated over 3,500 trackable fragments and an estimated 150,000+ pieces larger than 1 mm. Because of the high altitude, most of this debris will remain in orbit for centuries.