Icarus
Key facts
- What it is
- Near-Earth asteroid (Apollo group)
- Size
- About 1.3 km across
- Discovered
- 1949, by Walter Baade
- Spacecraft
- Not yet visited
- Orbit group
- Apollo
- Average distance from the Sun
- 1.08 au (about 160 million km)
- Time to go round the Sun
- 409 days
- Closest and farthest from the Sun
- 0.19 to 1.97 au
- Tilt of its orbit
- 22.8°
- Closest its orbit comes to Earth's
- 5,100,000 km (13 times the Moon's distance)
- Spins once every
- 2.3 hours
An au (astronomical unit) is Earth's average distance from the Sun, about 150 million km. Orbit figures are from open tracking data, figures last updated 1 Nov 2026.
Icarus is named after the young man in Greek legend who flew too close to the Sun, and the name fits. Its long, stretched orbit carries it closer to the Sun than the planet Mercury, to about 28 million kilometres, where its surface is heated to several hundred degrees Celsius. At the other end of its orbit it travels out beyond Mars. Walter Baade discovered it at the Palomar Observatory in California on 27 June 1949.
Icarus is about 1.3 kilometres across and spins quickly, once every two hours and sixteen minutes.
In June 1968 it passed about 6 million kilometres from Earth, roughly 16 times the distance to the Moon. That was not a near miss, but it caught the public imagination. A professor at the Massachusetts Institute of Technology set his engineering students a class project: imagine that Icarus were heading for Earth, and design a way to stop it. Their report, known as Project Icarus, was published as a book and inspired a film. It was one of the first serious studies of how to deflect an asteroid, decades before the DART mission tested the idea in 2022.
Icarus has a scientific use too. Because it swings so close to the Sun, its orbit is affected by the Sun's strong gravity in the way Einstein's theory of general relativity predicts, making it a natural test of that theory, just as Mercury is.
Icarus's orbit crosses Earth's, so it is an Apollo asteroid, but it poses no hazard. Its path is well known, and its future approaches are all at safe distances.
Coming close to Earth
Its next passes within about 30 million km of Earth, worked out from its orbit. Each one is a safe miss.
| Date | Distance | In Moon distances |
|---|---|---|
| 13 Jun 2043 | 8,800,000 km | 23 |
| 18 Jun 2062 | 12,000,000 km | 32 |
| 10 Jun 2071 | 27,000,000 km | 70 |
| 14 Jun 2090 | 6,500,000 km | 17 |
| 19 Jun 2109 | 15,000,000 km | 38 |
| 11 Jun 2118 | 24,000,000 km | 63 |