Delta 4 second stage chosen for Orion tests

Delta IV upper stage utilized on a variety of configurations [NASA/USAF].

Todd HalversonFlorida TodayNASA intends to use a modified Delta IV second stage to launch Orion spacecraft on an unmanned test flight in 2017 and then a human expedition to lunar orbit four years later.The Boeing upper stage is “the only means available to support the immediate in-space propulsion needs” for the excursions, NASA said in a procurement notice issued early this month.The missions both are to be launched from complex 39B at Kennedy Space Center on early versions of NASA’s new heavy-lift Space Launch System.The second stage for the first flight must be delivered to KSC no later than the fourth quarter of 2016, the notice said. The fourth quarter of 2020 is the deadline for delivery of the upper stage for the second mission.NASA performed an internal market study of in-space propulsion systems available in the U.S., Europe and Japan, the notice said. From that research, NASA determined that the Delta IV upper stage “is the only known in-space stage requiring relatively minor modifications” to meet mission requirements as well as the launch schedule, the notice said.Moreover, NASA said no other in-space propulsion system – “either existing with ...