No mission in the Gemini program better displayed American adaptability than the dual flight of Gemini VII and Gemini VI-A. Originally, Gemini VI was to dock with an Agena target vehicle in October 1965; when the Agena exploded during launch, the mission seemed lost. Engineers at McDonnell Aircraft proposed an audacious alternative: launch the long-duration Gemini VII first, then send Gemini VI-A to rendezvous with it in orbit. On December 4, Frank Borman and Jim Lovell lifted off for what would become a fourteen-day marathon—then the longest human spaceflight in history. On December 12, Wally Schirra and Tom Stafford sat on the pad as their Titan engines ignited, then shut down one second later because a launch umbilical separated prematurely. Schirra declined to eject, judging—correctly—that the booster had not lifted off. Three days later, they tried again. On December 15, after four carefully calculated thruster burns, Schirra and Stafford caught up with Borman and Lovell. The two spacecraft flew in formation, at times nose-to-nose only inches apart, while all four astronauts took turns maneuvering. It was the first true rendezvous in space—achieved by the United States first—and it proved that orbital mechanics could be mastered with precision. The crews joked across the void; Schirra and Stafford even held up a "Beat Army" sign for West Pointer Borman. Gemini VI-A splashed down on December 16; Borman and Lovell endured two more days before their own recovery on December 18. The Moon suddenly seemed much closer.