USA-193, also known as NROL-21 21, was a U.S. military reconnaissance satellite (radar imaging) launched on 14 December 2006. It was the first launch conducted by the United Launch Alliance. Owned by the National Reconnaissance Office (NRO), the craft's precise function and purpose were classified.

The satellite malfunctioned shortly after deployment and was intentionally destroyed 14 months later on 21 February 2008 by a modified SM-3 missile fired from the warship USS Lake Erie, stationed west of Hawaii. The event highlighted growing distrust between the U.S. and China, and was viewed by some to be part of a wider "space race" involving the U.S., China, and Russia.

It was the first launch by United Launch Alliance since it was formed in December 2006, and the first Delta II launch since ULA acquisition.