It Would Take Thousands:

Space-based defense against an ICBM attack will not come without a heavy price tag since it would require a thousand or more space-based interceptors to do the job, according to RAND senior nuclear policy analyst David Mosher and Union of Concerned Scientists physicist and long-time critic of space weapons Laura Grego. During a media roundtable on space security in Washington this week, Mosher and Grego agreed that to be effective, a space-based, boost-phase missile defense system would require at least 1,000 interceptors. They also said that because of the short response time required to strike a ballistic missile, the interceptors would have to be in low orbit, making them vulnerable to short-range missiles. What’s more, they maintain, the space-based interceptors must be able to maneuver extensively, so propellant load would be high, adding to the spacecraft’s mass and cost. Despite such a dismal technological picture, Grego said the Pentagon’s outyear budget contains provision for a test system.