Key Facts

  • Categorized as a Aten-class Asteroid
  • Comparable in size to a school bus or smaller
  • Will pass within 2,102,179 km of Earth in 2021
  • Classified as a Near Earth Asteroid (NEA)
  • Not a Potentially Hazardous Object
  • See orbit simulation


2021 SG1 is a very small asteroid whose orbit could bring it in close proximity to Earth. NASA JPL has classified 2021 SG1 as a "Near Earth Asteroid" due to its orbit's proximity to Earth, but it is not considered potentially hazardous because computer simulations have not indicated any imminent likelihood of future collision.

2021 SG1 orbits the sun every 346 days (0.95 years), coming as close as 0.77 AU and reaching as far as 1.16 AU from the sun. Based on its brightness and the way it reflects light, 2021 SG1 is probably between 0.014 to 0.060 kilometers in diameter, making it a small to average asteroid, very roughly comparable in size to a school bus or smaller.

Close Approaches

2021 SG1's orbit is 0.00 AU from Earth's orbit at its closest point. This means that its orbit is relatively close to Earth's orbit.

2021 SG1 has 7 close approaches predicted in the coming decades:

Date Distance from Earth (km) Velocity (km/s)
Sept. 22, 2021 2,102,179 8.252
Feb. 22, 2024 13,684,291 7.941
Sept. 23, 2039 10,839,266 6.408
Feb. 12, 2042 21,075,257 10.597
Sept. 22, 2056 6,319,322 8.944
Feb. 26, 2059 14,143,826 7.451
Sept. 22, 2074 2,620,272 7.531

Images and Observations

2021 SG1's orbit is determined by observations dating back to Sept. 26, 2021. It was last officially observed on Oct. 1, 2021. The IAU Minor Planet Center records 20 observations used to determine its orbit.

Accessibility and Exploration

2021 SG1 can be reached with a journey of 370 days. This trajectory would require a delta-v of 9.3 km/s. To put this into perspective, the delta-v to launch a rocket to Low-Earth Orbit is 9.7 km/s. There are 24,641 potential trajectories and launch windows to this asteroid.

See more at the NHATS Mission Trajectories table for 2021 SG1.

Similar Objects

These objects have orbits that share similar characteristics to the orbit of 2021 SG1:



   or view a random object

Orbital Elements

  • Epoch: 2460200.5 JD
  • Semi-major axis: 0.9644 AU
  • Eccentricity: 0.1991
  • Inclination: 9.59°
  • Longitude of Ascending Node: 180.22°
  • Argument of Periapsis: 65.34°
  • Mean Anomaly: 120.74°

Physical Characteristics

  • Diameter: ~0.037 km
  • Magnitude: 25.55

Derived Characteristics

  • Orbit Period: 346 days (0.95 years)
  • Avg. Orbit Speed: 30.32 km/s
  • Aphelion Distance: 1.16 AU
  • Perihelion Distance: 0.77 AU

Map Comparison

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Orbit Simulation

Sky Map

The position of 2021 SG1 is indicated by a ◯ pink circle. Note that the object may not be in your current field of view. Use the controls below to adjust position, location, and time.

Size Rendering

The below comparison is an artistic rendering that uses available data on the diameter of 2021 SG1 to create an approximate landscape rendering with New York City in the background. This approximation is built for full-resolution desktop browsers. Shape, color, and texture of asteroid are imagined.