Without a telescope
BarelyOnly on its best passes and from a dark site: magnitude +4.8 at its best, at the limit of the naked eye. Binoculars make it easy.
Satellites›Brightest satellites›ERS-1
ERS-1
ERS-1 is a satellite from the European Space Agency, launched on July 17, 1991 from Kourou, French Guiana. It is in a low orbit, 737 to 783 km above the ground, and goes around the Earth every 100.0 minutes: 14.4 times a day, at 7.47 km/s (26,900 km/h). The orbit is sun-synchronous: it crosses every place at about the same local time of day.
Where ERS-1 is right now
The gold ring is its orbit, and the line drops to the point on the ground under it. Inside the white circle it is above the horizon. Drag the globe to turn it, pinch or use the buttons to come closer; the target button brings you back to the satellite. The 2D map shows its path over the ground for the next lap: gold where it is in sunlight, dashed where it is in Earth’s shadow.
Finding ERS-1…
ERS-1
Finding ERS-1…
- Over
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- Position
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- Height
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- Speed
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- Now
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- Your time
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Can you see it?
From where
Its orbit crosses close to both poles, so sooner or later it passes over every place on Earth.
A satellite shows only when your sky is dark and it is still in sunlight: in the hours after dusk and before dawn.
When it passes over you
The app works out its passes over your exact location, alerts you before one, and leads you to it with an arrow in the camera view.
The facts
- Catalogue number (NORAD)
- 21574
- International designator
- 1991-050A
- Type
- Satellite
- Belongs to
- European Space Agency
- Launched
- July 17, 1991
- Launched from
- Kourou, French Guiana
- Status
- Not operational
- Orbit
- Low Earth orbit, sun-synchronous
- Lowest point
- 737 km
- Highest point
- 783 km
- Tilt to the equator
- 98.8°
- One lap
- 100.0 minutes
- Laps a day
- 14.40
- Speed
- 7.47 km/s
- At its brightest
- mag +4.8 estimated, overhead
- Standard brightness
- mag +5.5 from 1,000 km, half lit
- Size on radar
- 10 m²
Orbit measured November 12, 2026, from CelesTrak. Heights are above the ground at the equator. Page updated November 14, 2026.
Quick answers
Where is ERS-1 right now?
The map on this page shows where ERS-1 is at this moment, the path it will follow over the ground for the next lap, and the part of the Earth it is above the horizon for. It is worked out from the latest tracking data.
How high is ERS-1?
Between 737 km at its lowest and 783 km at its highest, above the ground.
How fast does ERS-1 go?
About 7.47 km/s, which is 26,900 km/h. One lap of the Earth takes it 100.0 minutes, so it goes around 14.4 times a day.
Can you see ERS-1 without a telescope?
Barely. Only on its best passes and from a dark site: magnitude +4.8 at its best, at the limit of the naked eye. Binoculars make it easy.
When was ERS-1 launched?
On July 17, 1991, from Kourou, French Guiana.
With the app
Knowing where it is over the Earth is one thing. The app shows you where it is in your sky.
This page follows the satellite around the planet. The app works out when it passes over you, and leads you to it.
- Every pass over your exact location, for this satellite and 10,000+ more.
- An alert before it rises, so you are outside in time.
- An arrow in the camera view that leads you to the exact spot in the sky.
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