Explorer 4
Explorer 4 was a U.S. Army geophysics satellite designed to measure charged particles in Earth's radiation environment. Its detectors extended the early Explorer observations and recorded how the trapped-radiation regions responded during the 1958 high-altitude nuclear tests of Operation Argus.
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Identity
- Aliases
- Explorer IVSatellite 1958 Epsilon1958-005A
- Name
- Explorer 4
- Slug
- explorer-4
- Status
- completed
Details
- Astronauts
- -
- Description
- Explorer 4 was a U.S. Army geophysics satellite designed to measure charged particles in Earth's radiation environment. Its detectors extended the early Explorer observations and recorded how the trapped-radiation regions responded during the 1958 high-altitude nuclear tests of Operation Argus.
- End Date
- 1959-10-23
- Launch Site
- Outcome
- Explorer 4 reached Earth orbit and returned radiation measurements that expanded knowledge of the natural Van Allen belts and observed artificial electron populations produced by Operation Argus. The spacecraft reentered on October 23, 1959.
- Program
- Explorer
- Start Date
- 1958-07-26
- Vehicle Families
Links
Assets & Meta
- Creation Time
- July 18, 2026 at 18:38:22 UTC
- Updated Time
- July 18, 2026 at 18:38:22 UTC
Other
- Affiliations
- Space Stations
- -
- Vehicles