https://www.nytimes.com/2020/01/09/w...h-ukraine.html- Jan. 9, 2020 Updated 8:56 p.m. ET
American satellites, designed to track missile launches, detected the firing of the Iranian short-range interceptor. United States intelligence agencies later picked up Iranian communications confirming that the system brought down the Ukrainian airliner, officials said.
Iranian officials questioned the Western account, saying the plane would have exploded if hit by a missile. The air defense system used Wednesday, however, is designed to explode near aircraft, creating shrapnel that takes a plane out of the sky, rather than directly hitting it.
In addition to denying responsibility, Iran invited the National Transportation Safety Board of the United States to assist in the investigation despite previous reports that the Americans would not be involved, according to correspondence reviewed by The Times. The board assigned an investigator to the crash, a spokesman said on Thursday evening.