McDonnell plant for an integrity test. May 15, 1960 (Sunday) The Soviet Union launched Sputnik IV, a five-ton mockup of a crewed spaceship, as a prelude to putting human beings into outer space. The satellite carried a heavy life-size dummy, luckily; the retrorockets fired in the wrong direction, sending the ship into a higher orbit rather than returning it to Earth. The satellite would re-enter Earth's atmosphere on September 5, 1962, with a fragment landing at the intersection of North 8th Street and Park Street in Manitowoc, Wisconsin. While in Paris with President Eisenhower on the first day of a summit with Soviet Premier Khrushchev, U.S. Secretary of Defense Thomas S. Gates, Jr. ordered a test of the American military alert system. Declassified documents would later show that Gates's order at 0033 UTC for "a high state of command readiness" was misunderstood, and that within half an hour, the U.S. Joint Chiefs of Staff placed troops worldwide at DEFCON 3 status. The American public learned of the alert when Lowry Air Force Base asked police to locate key personnel, and the police asked Denver radio station KOA (AM) and KOA-TV to assist. The message that followed- "All fighter pilots F-101 and fighter pilots F-102... Doe Three Alert, Hotcake One and Hotcake Six, scramble at Lowry immediately." was heard by thousands of Denver listeners. The new Convair 880 made its first passenger flight, for Delta Air Lines. Qualification tests for the Mercury spacecraft explosive egress hatch were completed. May 16, 1960 (Monday) Shortly after the Four Power Summit in Paris was opened by France's President DeGaulle at , Soviet Premier Nikita Khrushchev demanded the right to speak, and then delivered an angry tirade, which ended with a cancellation of the invitation for President Eisenhower to visit the U.S.S.R. beginning June 10. The summit ended at , and Khrushchev did not show up for further meetings. Eisenhower, Khrushchev and Britain's Prime Minister Macmillan left France three days later. On May 16 and 17, representatives of NASA's research centers gathered at Langley Research Center to present papers on current programs related to space rendezvous and to discuss possible future work on rendezvous. During the first day of the conference, papers were read on the work in progress at Langley, Ames, Lewis, and Flight Research Centers, Marshall Space Flight Center, and Jet Propulsion Laboratory. The second day was given to a roundtable discussion. All