Kholod

The hypersonic rocket uses a scramjet engine and was created to exceed Mach 6+ The prototype consists of a Soyuz TMKB with liquid hydrogen and modified fillings from the SA-5 Gammon missiles.

The Kholod became part of a joint CIAM/NASA project to enhance the fundamental understanding of variable geometry ram/scramjet hybrids beginning in the 1990s.

The Kholod contained an array of 83 pressure transducers and 58 thermocouples, to monitor the effects of hypersonic flow on the leading edge and inlet.

The Kholod's sustained run of its dual mode ramjet/scramjet was primarily enabled by the development of a new alloy named "FeCrAl".

The information obtained by the Hypersonic Flying Laboratory enabled researchers to begin designing the next generation of ramjets and scramjets.