USSR Styx Surface-Surface Missile aka P-15 Termit, designed by Raduga.

This is the Styx, a surface-to-surface, anti-ship missile that became operational with the former Soviet Navy in 1958. A solid-fuel booster (not shown here) launched the missile, and a built-in rocket engine sustained its flight. It had a range of about 26 miles.

The Soviet Union supplied its allies with Styx missiles. An Egyptian Styx sank the Israeli destroyer Eilat during the Six-Day War in 1967. They were also used during the Vietnam and Persian Gulf wars and during conflicts between India and Pakistan. The People's Republic of China produced its own versions of the Styx. This object was donated to the Smithsonian in 1995 by the U.S. Air Force.

Photo 151s, Smithsonian Udvar-Hazy Center, May 2013