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Mission record

Explorer 33

Also known as AIMP 1, Anchored IMP 1, IMP-D

NASA · Launched

Explore trajectory

Completed · Partial success

NASA spin-stabilized IMP-D spacecraft planned to be the first U.S. spacecraft to go into lunar orbit; excess launch velocity left it in a highly elliptical Earth orbit, from which it measured the interplanetary magnetic and radiation environment until 1971.

Destinations
Moon
Launch vehicle
Delta
Launch site
Cape Canaveral, United States
Countries
United States
Mission types
Orbiter, Heliophysics

Chronology

Mission timeline

  1. Launch

    Explorer 33 launched from Cape Kennedy, Florida

    Earth

  2. Milestone

    Engineers used an electronic "screwdriver" remotely to restore power to the blacked out bus

    Earth

  3. Mission end

    No data were obtained after 21 September 1971

    Earth

Mission architecture

Vehicles

  • Explorer 33 · Spacecraft

    Destinations: Moon

Trajectory record

Trajectory dataset not yet available

No verified trajectory dataset is committed for this mission, so Mission Atlas renders no path.

Provenance

Sources

Each source is listed once and labeled with the mission, event, trajectory, or destination/body context it supports.

Data verified through August 24, 2026