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}} Delta IV is an expendable launch system in the Delta rocket family. Delta IV uses rockets designed by Boeing's Integrated Defense Systems division and built in the United Launch Alliance (ULA) facility in Decatur, Alabama. Final assembly is completed at the launch site by ULA. The rockets were designed to launch payloads into orbit for the United States Air Force Evolved Expendable Launch Vehicle (EELV) program and commercial satellite business. Delta IV rockets are available in five versions: Medium, Medium+ (4,2), Medium+ (5,2), Medium+ (5,4), and Heavy, to cover a range of payload size and weight. Delta IV was primarily designed to satisfy the needs of the U.S. military. The rockets are assembled at the Horizontal Integration Facility for launches from SLC-37B at Cape Canaveral, and in a similar facility for launches from SLC-6 at Vandenberg Air Force Base. ==History== The Delta IV entered the space launch market when global capacity was already much higher than demand. Furthermore, as an unproven design it has had difficulty finding a market in commercial launches, and the cost to launch a Delta IV is higher than that for competing vehicles. In 2003, Boeing pulled the Delta IV from the commercial market, citing low demand and high costs. In 2005, Boeing stated that it sought to return the Delta IV to commercial service. All but one of the first launches have been paid for by the U.S. Government. In 2015, ULA stated that a Delta IV Heavy is sold for nearly $400 million. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Delta IV」の詳細全文を読む スポンサード リンク
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