India's Missile Carrying Satellite

 

India's unexpected launch of an anti-satellite missile test this week sparked surprise (and some alarm) among international and aerospace-industry experts. The test's success makes India the fourth country capable of destroying an enemy satellite, after the U.S., Russia and China. But how does that technology work?

An anti-satellite weapon, or ASAT, is anything that destroys or physically damages a satellite. That's the broad definition. 

"The problem with defining an ASAT is that since most space technology is dual-use, ASATs come in many non-overt forms," Joan Johnson-Freese, professor of national security affairs at Naval War College in Newport, Rhode Island, said in an email to Space.com.

Indian Prime Minister Narendra Modi declared on Wednesday (March 27) that the country had pulled off an ASAT missile launch that same day. The launch, "Mission Shakti," likely struck an Indian satellite in low Earth orbit, turning the object into debris. ASATs take many shapes, but the clearest examples follow kinetic-kill models, in which an object in space or on the ground is sent to collide with an orbiting satellite, destroying both object and target with the energy of the crash.

But an ASAT doesn't need to be airborne. "If the intent is to stop the transmission of information from the satellite to the ground, taking out the ground station achieves the same goal, without the space debris," Johnson-Freese said.