Explorer 1
Explorer 1 was the first satellite launched by the United States, carrying scientific instruments to study Earth's radiation environment.
Also known as: Explorer I, 1958 Alpha 1
How big is it?
2.03 m long
Overall spacecraft length · specified
Typical recorded range: 2 m to 2.1 m.
A little perspective
About the same scale as Elkhorn coral colony.
Elkhorn coral colony: An elkhorn coral colony is a branching formation of the coral species Acropora palmata, found in shallow Caribbean reefs.
Measurements, assumptions & sources +
Explorer 1
Explorer 1, the first US satellite, was about 2.03 m long and 14 kg including its instrumented cylindrical body. Antennas are contextual.
The marked overall spacecraft length is calibrated. Unmeasured illustration details are representative.
Elkhorn coral colony
A defined mature elkhorn coral (Acropora palmata) colony 2 m wide and 1.2 m high. Branch growth and breakage produce irregular colonies; the basal reef substrate is excluded from both spans.
NOAA Fisheries — Elkhorn coral
The marked defined colony width is calibrated. Unmeasured illustration details are representative.
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Why this measurement?
Why we use 2.03 m
For comparison, this page uses overall spacecraft length. The record labels this value specified, so the stated convention rather than an inferred average controls the comparison. The recorded range is 2 m to 2.1 m.
Explorer 1, the first US satellite, was about 2.03 m long and 14 kg including its instrumented cylindrical body. Antennas are contextual.
The marked horizontal span follows the named feature; transparent margins and unmeasured details do not alter it. How calibrated comparisons work →
Recorded properties
Explorer 1 dimensions and measurements
| Property | Selected value | Recorded range | Basis |
|---|---|---|---|
| 2.03 m | 2 m to 2.1 m | specified | |
| 13.97 kg | 13.9 kg to 14.1 kg | specified |
Around this scale
Go smaller. Go bigger.
These links use compatible length records, ordered around the selected value.
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Nearest higher value · SpaceNew Horizons spacecraft2.2 mNew Horizons is a NASA spacecraft launched to study Pluto and the Kuiper Belt, carrying scientific instruments and powered by a radioisotope generator.Sources and method
Want to check the number?
The source records and measurement method remain available for inspection.
- NASA — Explorer 1 overviewFirst US satellite dimensions, mass and mission context.
There’s always another scale
Follow your curiosity.
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PeopleAdult in a spacesuit1.9 mAn adult in a spacesuit is a person wearing a pressurised suit and life-support system for survival outside Earth's atmosphere.SpaceNew Horizons spacecraft2.2 mNew Horizons is a NASA spacecraft launched to study Pluto and the Kuiper Belt, carrying scientific instruments and powered by a radioisotope generator.
SportBasketball backboard1.8 mA basketball backboard is a flat, rigid board mounted behind the hoop to provide a surface for rebounding and scoring.
TransportPedal-powered rail trolley2.4 mA pedal-powered rail trolley is a lightweight vehicle propelled by pedalling, designed to travel along railway tracks for recreation or transport.
Everyday thingsDouble bed1.9 mA double bed is a wider bed designed to accommodate two people.