The Friendship 7 Hand Controller
As originally envisioned by the engineers at NASA and McDonnell Aircraft, the Mercury capsule was designed to fly through space using only an automatic control system to keep the spacecraft’s attitude in correct alignment. One of the first requests by the Mercury astronauts was the installation of a three-axis hand controller used to gain manual control of the spacecraft in case the automatic system failed.
This request proved prophetic when the automatic system malfunctioned during John Glenn’s Friendship 7 space flight on February 20, 1962. Glenn successfully used the three-axis hand controller to manually keep the spacecraft in alignment during the second and third orbits.
After the space flight, NASA engineers presented Glenn with the hand controller from the Friendship 7 spacecraft to commemorate his achievement. It is mounted on a wooden plaque along with the thruster that failed during the space flight.
These two pages contain John Glenn’s early notes on the design of a three-axis hand controller and the corresponding instrumentation for the Mercury capsule.
This schematic drawing shows the location of the various thrusters on a Mercury capsule used to control the pitch, yaw, and roll attitudes of the spacecraft. Early in the second orbit of John Glenn’s Friendship 7 space flight the 1 pound yaw thruster (located on the front left side of the capsule in the drawing) broke while the capsule was in automatic control mode.The faulty thruster kept firing, which pushed the spacecraft 20 degrees to the right. As a result, the 5 pound thruster mounted on the capsule’s right side would fire to correct the yaw attitude. In order to preserve the control system’s limited amount of hydrogen peroxide fuel, Glenn manually flew the spacecraft for the remainder of the mission.
