Space News cites the Atlantic Council for hosting an event with General William L. Shelton, commander of US Air Force Space Command:
Meanwhile, Shelton — during the briefing and in a speech at the Atlantic Council here earlier in the day — declined to say which U.S. satellites, if any, provided intelligence that helped U.S. authorities to determine that a missile launched from rebel-held Ukrainian territory shot down the Malaysian airliner. The Air Force operates missile warning satellites that can pick up the infrared-heat signature of a large surface-to-air missile, while classified signals intelligence satellites are able to determine whether radars used to guide such weapons have been activated.
Shelton said the Air Force only acknowledges the ability of its Space Based Infrared System missile warning satellites to detect strategic-class missiles and space launches, even though they are widely known to be able to detect shorter-range missiles. Shelton did say, however, that “They are very good satellites. They are very sensitive satellites.”