Two prominent engine manufacturers, Alliant Techsystems and Pratt & Whitney Rocketdyne announced major upgrades of their existing rocket motors for future launches to low earth orbit.
Pratt & Whitney Rocketdyne announced that the RS-68A motor, an upgrade of the RS-68, has passed its Design Certification Review. The engine is the largest hydrogen-fuel engine in the world, used to power the largest American commercial rocket, the Boeing Delta IV-Heavy. One RS-68A has already been integrated to Delta-IV Heavy in Alabama; one additional engine is undergoing integration, and the third will follow in May, according to the Rocketdyne press release. The RS-68A will deliver roughly 22,500 kg (50,000lbs) more thrust than its predecessor.
ATK announced a contract from Orbital Sciences to develop the Castor 30XL, a significant modification of their standard second-stage Castor 30 engine (which has been redesignated Castor 30A. The Castor 30A delivers roughly 45,000 kg (89,000lbs) of thrust and burns for 146 seconds; the new version's performance is undisclosed at this time. The upgraded Castor 30XL will power the third flight of Orbital Sciences' new Taurus II rocket.