Strypi is a two-stage US sounding rocket. Its first stage consists of two Recruit, the second of one Castor. It is 31 inches (79 centimeters) in diameter, and has a maximum flight height of 124 miles (200 kilometers).

It was originally designed and built in 1962 by teams from the Sandia National Laboratories in an around-the-clock program that was a part of a larger nuclear weapons testing program, undertaken prior to the imposition of the Limited Test Ban Treaty (LTBT) in October, 1963. It was designed to take a nuclear warhead into space for extra-atmospheric testing. Though it performed this function only once, in Test Checkmate of Operation Fishbowl, it became the "workhorse" of Sandia's rocket research program.^[1] The rocket's name came from the efforts of the Sandia teams, which had "taken the tiger by the tail".^[1]

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.^[1]

American target missile. Family of re-entry vehicle test boosters and anti-missile targets using a Castor first stage with two recruit strap-ons, plus a range of upper stages.

The SPARK, also known as the Super Strypi, is a three-stage derivative of the Strypi powerful enough to place a 250 kg payload into Sun-synchronous orbit. The Super Strypi was first launched on 3 November 2015, although on that test the first stage failed soon after lift-off.