U.S. spy satellites did not detect a midair explosion at the time that Malaysia Airlines Flight 370 lost contact with air traffic controllers or in the hours immediately afterward, senior U.S. intelligence officials told NBC News on Wednesday.
"That's one thing that is particularly vexing," said one.
The official, who spoke on condition of anonymity, said that analysis of data from "national technical means" -- a euphemism for spy satellites -- found nothing "to corroborate or indicate a midair explosion" in the period surrounding the jet's disappearance on Saturday (Friday in the U.S.).
The U.S. Space Based Infrared (SBIR) satellite system, which is designed to identify heat signatures in real time, can -- and has -- detected exploding aircraft, according to a second official,. Indeed, it has provided evidence in the past of events as small as artillery fire and the launch of anti-aircraft missiles, the official said.
The system uses dedicated infrared satellites and sensors on other military spacecraft to gather the data.
Jeffrey T. Richelson, an intelligence historian who has written extensively about SBIR and its predecessors, agrees and says the intelligence community has supplemented civilian investigations of missing aircraft in the past.
Both the second intelligence official and Richelson said the U.S. intelligence community archives the satellite system's infrared signals by type - explosions, detonations and launches -- so new incidents can quickly be identified.
In his book, "America's Space Sentinels," Richelson cited several examples of where SBIR and its predecessor, the DSP system, detected explosions of civilian and military aircraft in midair, including the blasts that took down TWA Flight 800 in July 1996 and a midair collision between U.S. and German military aircraft off the Atlantic coast of South Africa in September 1997.
In an email exchange with NBC News this week, Richelson also said that DSP data were examined for clues in the aftermath of Air France Flight 447's disappearance while en route from Rio de Janeiro to Paris in June 2009. It also has detected in real time the crashes of several U.S. military aircraft.
Data from SBIR are downloaded and initially analyzed at Buckley Air National Guard Base in Aurora, Colo.