Ranger 2 was intended to test new technologies to take humankind to the Moon. Credit: NASA/JPL-Caltech

A rocket malfunction stranded this U.S. Moon mission in Earth orbit.


Like its predecessor, Ranger 2 was designed to operate in a highly elliptical Earth orbit that would take it into deep space beyond the Moon. Mission planners expected that during five months of operation, they could verify both the technical design of the vehicle and conduct key scientific experiments to study the space environment over a prolonged period. Since the Block 1 Rangers (Ranger 1 and 2) carried no rocket engine, they could not alter their trajectories.

On this attempt, Ranger 2, like its predecessor, failed to leave low-Earth orbit, the Agena B stage having failed to fire. In its low orbit, Ranger 2 lost its solar orientation and then eventually lost power, and reentered on Nov. 19, 1961.

The most probable cause of the failure was inoperation of the roll-control gyroscope on the Agena B guidance system. As a result, the stage used up all attitude control propellant for its first orbit insertion burn. At the time of the second burn, without proper attitude, the engine failed to fire.


Siddiqi, Asif A. Beyond Earth: A Chronicle of Deep Space Exploration, 1958-2016. NASA History Program Office, 2018.

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