Technicians wearing clean-room attire inspect the Pioneer 3 probe before shipping it to Cape Canaveral, Fla. Image credit: NASA/JPL-Caltech
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The Pioneer 3 mission was one of the first attempts by the United States to send a spacecraft to the moon. Because of a malfunction with the spacecraft's booster rocket, it lacked the velocity to make it beyond Earth orbit and fell back to Earth, burning up over Africa.
Pioneer 3 was, however, equipped with a Geiger counter to study interplanetary radiation and managed to discover and map the outer Van Allen radiation belt around Earth before its demise.
- Geiger counters