April 7, 1983: Astronauts Story Musgrave and Don Peterson perform the first spacewalk of the space shuttle era. Tethered to the Challenger by safety slide wires, they were able to move along the cargo bay without floating off into space. The extra-vehicular activity (EVA) lasted 4 hours, 17 minutes.
On April 16, 1972, the Apollo 16 mission blasted off from Cape Canaveral on a journey to the Moon. Astronauts John Young, Charlie Duke, and Ken Mattingly went on the penultimate adventure of the Apollo program with a mission that lasted 11 days, 1 hour, and 51 minutes, ending at 2:45 PM EST on April 27.