Trumpet signals intelligence satellites are equipped with a large deployable mesh antenna, and were designed to monitor Soviet communications and missile tests. They are placed into Molniya-type orbits.

Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

• 4 - McDowell, Jonathan, Jonathan's Space Report (Internet Newsletter), Harvard University, Weekly, 1989 to Present. HTML when accessed: ftp://sao-ftp.harvard.edu/pub/jcm/space/news