NASA eyes Delta IV stage

NASA plans to use a modified Delta IV second stage atop an early version of the Space Launch System for the unmanned Orion test flight in 2017, as well as for the manned flight four years later. In a May 3 procurement notice, NASA said the Boeing-designed Delta IV second stage is the only means available to support the immediate propulsion needs, and it’s the only one that requires relatively minor modifications to launch astronauts by 2021. (Source: Florida Today, 05/16/12; NASA procurement notice, 05/03/12) Gulf Coast note: The Orion crew vehicle is built at Michoud Assembly Facility, New Orleans; the SLS first stage will use four RD-25 engines, tested at Stennis Space Center; Delta IV is built in Decatur, Ala., by Boeing and Lockheed Martin's United Launch Alliance. The first stage is powered by RS-68 engines, tested at SSC, and the second by a Pratt & Whitney RL-10; NASA and the Air Force are studying a replacement for the RL-10 class.