The United States launched three more Mercury flights after Glenn's: Aurora 7 on May 24, 1962 duplicated Glenn's three orbits; Sigma 7 on October 3, 1962, six orbits; and Faith 7 on May 15, 1963, 22 orbits (32.4 hours), the maximum capability of the spacecraft. NASA at first intended to launch one more mission, extending the spacecraft's endurance to three days, but since this would not beat the Soviet record, it was decided instead to concentrate on developing Project Gemini.

Answer this question, if possible (if impossible, reply "unanswerable"): How many more Mercury missions were there after John Glenn's?
3