Strypi is the name of a US sounding rocket. The Strypi has two stages. The first stage consists of two Recruit, the second of one Castor-rocket. The Strypi has a maximum flight height of 200 kilometres and a diameter of 79 centimetres. In 1968, a modified Strypi was used in Material Test Vehicle (MTV) booster tests. Although atmospheric nuclear testing was now banned, as a part of the Test Readiness Program the U.S. Air Force continued to develop the means of testing, should the ban be lifted.