For Tucson, Raytheon’s expansion is a huge vote of confidence. Above, a company rendering of a hypersonic missile at the edge of space.

Tucson-based Raytheon Missile Systems has been awarded a $174.7 million contract to develop a hypersonic missile concept for the Pentagon.

The contract from the Defense Advanced Research Projects Agency is for unspecified work on the Hypersonic Air-breathing Weapon Concept, which envisions a cruise missile that can travel over Mach 5, or five times the speed of sound, using a “scramjet” engine.

Initially, about $3.4 million of fiscal 2016 research and development funds have been obligated under the contract, according to a Defense Department contract notice.

The Pentagon is researching two types of hypersonic missiles to defeat increasingly sophisticated air defenses and attack heavily defended targets.

In April 2015, Raytheon was awarded a $20.5 million DARPA contract to develop another type of hypersonic technology, a “tactical boost-glide” missile.

The air-breathing scramjet relies on high speed for its power, pushing more air and fuel into the engine as it accelerates.

The boost-glide model rides a re-entry vehicle to extremely high altitudes, where it skips across the Earth’s upper atmosphere before gliding to its target.

Raytheon is competing for the DARPA hypersonic missile work with Lockheed Martin, which last month was awarded a $171 million contract for a scramjet version and $147 million contract for a tactical boost-glide concept.

In 2011, DARPA and Lockheed Martin tested the HTV-2, a hypersonic vehicle designed to travel at Mach 20, but it crashed into the Pacific Ocean after overheating.