Early warning satellite

The missile - now without hot exhaust behind it - is rendered invisible to the early warning satellite, making the relatively short first phases of an ICBM a crucial moment for detection.

[3] The United States was the first country to attempt to establish a space-based early warning system.

In 1983, a design error in the on-board software of the US-KS satellites led to the so-called fall equinox incident, which consisted of a false nuclear launch warning after a confusion between the heat caused by the reflection of solar radiation in clouds and that released by the launch of a nuclear missile.

In the early 1990s, after about ten years of operation, the coverage provided by these satellites was only partial, due to a reduction in the launch rate.

[6][7][8] In France, the Direction générale de l'Armement carried out preliminary tests for the development of an early warning satellite.

[9] China operates Huoyan-1 series satellites under the Tongxin Jishu Shiyan (TJS) program.

Artist's rendering of a US DSP phase III satellite.
Example of the firing sequence of the Minuteman III intercontinental ballistic missile: the propulsion allows detection by an early warning satellite during phases 2, 3 and 4 corresponding to the operation of the 3 stages of the missile (A, B and C). This missile rises to between 100 and 200 km in altitude (diagram not to scale).
Artist's rendering of a SBIRS-GEO satellite.
Observation of a Delta II rocket launch by a SBIRS satellite in 2008.