A 1/6 scale model of the AR1 engine currently in development by Aerojet Rocketdyne as a replacement for the Russian-built RD-180 engine that powers United Launch Alliance's Atlas 5 rocket.

The service awards $3.1 million to Orbital ATK, $6 million to Aerojet Rocketdyne and $5.4 million to Northrop Grumman.

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Mike Gruss is the chief content and strategy officer at SpaceNews. From 2013 to 2016 he was a senior reporter at SpaceNews covering military space. Previously, he was editor in chief of Sightline Media Group and worked as a reporter and columnist for...