Key Facts
- Categorized as a Main-belt Asteroid
- Comparable in size to the island of Manhattan (3.72 km diameter)
- Not a Near Earth Object
- Not a Potentially Hazardous Object
- See orbit simulation
Overview
Armstrong is a mid-sized asteroid circling the sun between Mars and Jupiter, inside the main asteroid belt. NASA JPL does not treat Armstrong as potentially hazardous, because its orbit never carries it near Earth.
One lap around the sun takes Armstrong 1,210 days (3.31 years). Over that circuit it swings between 1.77 AU and 2.67 AU from the sun, travelling at an average of 19.95 km/s. At 3.7 kilometers across, Armstrong is bigger than 99% of known asteroids — roughly the size of the island of Manhattan.
Armstrong has been watched long enough to time its spin: one full turn on its axis takes 5.97 hours.
No Close Approaches
At their nearest, the orbits of Armstrong and Earth stay 0.75 AU apart. That is a comfortable margin, and it holds at every point in the orbit.
Orbital simulations run by NASA JPL's CNEOS turn up no close approaches to Earth.
Images and Observations
The orbit of Armstrong is pinned down by sightings going back to Oct. 16, 1969, the most recent officially logged on March 28, 2023. The IAU Minor Planet Center holds 2,679 observations behind that solution.
Accessibility and Exploration
The NHATS study does not rate Armstrong as a realistic destination for a crewed mission.Similar Objects
These objects follow orbits with much the same shape and tilt as Armstrong:References
Search
or view a random objectOrbital Elements
- Epoch: 2460200.5 JD
- Semi-major axis: 2.219 AU
- Eccentricity: 0.2042
- Inclination: 3.96°
- Longitude of Ascending Node: 159.37°
- Argument of Periapsis: 150.58°
- Mean Anomaly: 162.14°
Physical Characteristics
- Diameter: 3.72000 km
- Magnitude: 14.6
- Albedo: 0.243
Derived Characteristics
- Orbit Period: 1,210 days (3.31 years)
- Avg. Orbit Speed: 19.95 km/s
- Aphelion Distance: 2.67 AU
- Perihelion Distance: 1.77 AU
- Rotation Period: 5.97 hours
Map Comparison
Size Rendering
An artistic impression, scaling Armstrong against the New York skyline from its measured diameter. The shape, colour and texture of the asteroid are invented; only the size is real. Built for full-size desktop browsers.
Orbit Simulation
Sky Map
A ◯ pink circle marks where Armstrong sits. It may fall outside your current field of view — use the controls below to change the position, location and time.