Near-Earth Object
2021 SD2
NASA ID: 54200440
2021 SD2 will pass Earth on 29 September 2026 at a distance of 40.96 lunar distances (LD) - about 15,746,855 km - travelling at 35,582 km/h. Its estimated diameter is between 11 and 25 metres, roughly the size of a double-decker bus (around 11 m long). NASA does not classify it as potentially hazardous.
Close Approach Date
29 September 2026
In 97 days
Miss Distance
40.96 LD
15,746,855 km
41 times the Moon's distance from Earth
Velocity
35,582 km/h
1.3 times the orbital speed of the International Space Station
Est. Diameter
11–25 m
Absolute Magnitude
H = 26.92
The brightness measure astronomers use to estimate size
Hazard Classification
Not Hazardous
The real orbit in 3D
The actual path of 2021 SD2 around the Sun, computed from JPL orbital elements. Drag to rotate, scroll to zoom, and use the time controls to run the orbit forwards or back.
Every recorded pass
Each dot is one close approach of 2021 SD2 to Earth between 2007 and 2063, from JPL's records. Lower means closer: a dot under the dashed line passed nearer than the Moon. The orange dot is the approach on this page.
Size Comparison
Reading the Numbers
- A lunar distance (LD) is the average gap between Earth and the Moon, about 384,400 km. It is the standard yardstick for close approaches. Read more →
- Diameter estimates come from brightness. A dark surface reflects less light than a bright one, so the true size can sit anywhere in the quoted range. Read more →
- Potentially hazardous is a watch-list label based on size and orbital proximity. It does not mean an impact is expected. Read more →
