Oct 11 1958

From The Space Library

PIONEER I, U.S.-IGY space probe under direction of NASA and with the AFBMD as executive agent, launched from AMR, Cape Canaveral, Fla., by a Thor-Able-I booster. It traveled 70,790 miles before returning to earth, determined radial extent of great radiation belt, first observations of earth's and interplanetary magnetic field, and first measurements of micrometeorite density in interplanetary space. The 39-pound instrumented payload did not reach escape velocity.

Instruments and Spacecraft, pp. 30-32.