Pioneer 1
Pioneer 1 (Able 2) — NASA's first launched spacecraft (11 October 1958). A guidance error left it short of escape velocity, so instead of reaching the Moon it flew a 43-hour ballistic arc out to 113,800 km and fell back, burning up over the South Pacific. It still mapped the extent of the Van Allen radiation belts on the way. (Its arc is shown representatively.)
Key facts
Mission & specifications
Mission
- Operator
- NASA / US Air Force
- Launched
- October 11, 1958
- Status
- Completed
Trajectory
- Distance from the Sun
- 1.01 AU
- Distance from Earth
- 17,230 km
- Distance from Venus
- 0.601 AU
Mission
Pioneer 1 holds a quiet distinction: it was the first spacecraft launched by NASA, which had opened its doors just ten days earlier. Sent on 11 October 1958 toward the Moon, it was meant to enter lunar orbit — an audacious goal for so early an age. A small error in the upper stage left it travelling slightly too slowly and at the wrong angle, so instead of escaping Earth it arced out on a long ballistic path, reaching 113,800 kilometres — nearly a third of the way to the Moon — before gravity drew it back. After forty-three hours it re-entered and burned up over the South Pacific. But it was far from a wasted flight: its instruments traced the shape and extent of the Van Allen radiation belts far from Earth and returned early data on the interplanetary magnetic field and micrometeorites — real science from the most successful of the three early Able probes.
- 1958NASA's first spacecraftLaunch
Launched ten days after NASA opened, aimed at lunar orbit.
- 1958Reaches 113,800 kmMilestone
A guidance error leaves it short of escape; it arcs a third of the way to the Moon, mapping the Van Allen belts, then falls back.
- 1958Re-entry over the PacificMission end
After 43 hours it re-enters and burns up over the South Pacific.
Images
Images from open archives · credit shown per image