Changes

====Space-based systems====

====Space-based systems====

Space-based systems generally aim to destroy a ballistic missile at the height of its trajectory.   

Space-based systems generally aim to destroy a ballistic missile at the height of its trajectory.

At this point, the missile is fragile and vulnerable.  The difficulty lies in detecting the object, deploying the countermeasure, and successful interception.  Several solutions have been proposed, including so-called "smart rocks" and "smart pebbles" which would be non-ballistic objects deployed to  intercept the missile, and at low-energy, deflect or destroy the ICBM.

==Criticisms==

==Criticisms==

There are many critiques of the original program, one of the most infamous being that of the [[Union of Concerned Scientists]].  Many criticisms did, however, come from the more neutral scientific and military community.{{fact}}

There are many critiques of the original program, one of the most infamous being that of the [[Union of Concerned Scientists]].  Many criticisms did, however, come from the more neutral scientific and military community.{{fact}}

[[Category:Military]]

[[Category:Military]]