juliensimon/neo-close-approaches

Near-Earth Object Close Approaches

Part of the Orbital Mechanics Datasets collection on Hugging Face.

All close approaches of Near-Earth Objects (asteroids and comets) to Earth within 0.05 AU (~7.5 million km), spanning 1900 to 2099. Currently 41,889 recorded approaches (31,994 past, 9,895 future predictions).

Dataset description

This dataset contains every known close approach of a near-Earth object (NEO) to Earth, computed by NASA's Center for Near-Earth Object Studies (CNEOS) at the Jet Propulsion Laboratory. The data is recomputed continuously as new observations refine orbit estimates and new asteroids are discovered.

Each record includes the closest-approach distance (with 3-sigma uncertainty bounds), relative velocity, absolute magnitude, and — where available — measured diameter. For objects without a measured diameter, we include estimates derived from absolute magnitude using standard albedo assumptions.

Near-Earth objects are asteroids and comets whose orbits bring them within 1.3 AU of the Sun, placing them on trajectories that can intersect Earth's path. They originate primarily from gravitational perturbations in the main asteroid belt -- resonances with Jupiter eject fragments into planet-crossing orbits over millions of years -- or from the disintegration of short-period comets. The population spans a vast size range, from sub-meter fragments to objects tens of kilometers across, with the current catalog heavily weighted toward objects larger than about 140 meters due to survey detection limits.

Close approaches within 0.05 AU (~19.5 lunar distances) are of particular interest for planetary defense. At these distances, gravitational perturbations from Earth can significantly alter an object's future orbit, a phenomenon that makes long-term trajectory prediction inherently uncertain. The 3-sigma distance bounds in this dataset reflect that orbital uncertainty: well-observed objects with long data arcs have tight bounds, while newly discovered objects may have approach distances uncertain by orders of magnitude. The velocity columns capture both the geocentric relative velocity (v_rel) and the hyperbolic excess velocity (v_inf), which together determine the kinetic energy of a potential impact and the feasibility of deflection missions.

The distinction between past and predicted future approaches is scientifically important. Historical approaches are constrained by astrometric observations and have well-determined parameters. Future predictions depend on orbit propagation and degrade in accuracy over time, especially for small objects with short observation arcs or those subject to non-gravitational forces like the Yarkovsky effect -- a thermal radiation pressure that slowly shifts asteroid orbits by up to ~0.01 AU per million years and is the dominant source of uncertainty for sub-kilometer NEOs on century timescales.

Schema

Column	Type	Description
designation	string	Primary designation (e.g. "433", "2024 YR4")
orbit_id	string	Orbit solution ID used for computation
close_approach_jd	float64	Close-approach time (Julian Date, TDB)
close_approach_date	datetime	Close-approach date/time (UTC)
distance_au	float64	Nominal approach distance (AU)
distance_min_au	float64	Minimum possible distance, 3-sigma (AU)
distance_max_au	float64	Maximum possible distance, 3-sigma (AU)
distance_ld	float64	Nominal approach distance (Lunar Distances)
velocity_relative_kms	float64	Velocity relative to Earth (km/s)
velocity_infinity_kms	float64	V-infinity / hyperbolic excess velocity (km/s)
time_uncertainty	string	3-sigma time uncertainty (e.g. "< 00:01" or "4_15:23")
absolute_magnitude	float64	Absolute magnitude H (brightness proxy for size)
diameter_km	float64	Measured diameter in km (null if unknown)
diameter_sigma_km	float64	Diameter 1-sigma uncertainty in km
full_name	string	Full formatted name/designation
estimated_diameter_min_m	float64	Estimated diameter (m) assuming albedo 0.25 (bright)
estimated_diameter_max_m	float64	Estimated diameter (m) assuming albedo 0.05 (dark)
is_pha	bool	Potentially Hazardous Asteroid flag (H <= 22 and distance <= 0.05 AU)

Quick stats

• 41,889 close approaches (1900--2099)
• 4,247 involving Potentially Hazardous Asteroids
• 1,029 objects with measured diameters
• Closest recorded approach: (2025 UC11) at 0.02 LD (0.000044 AU)

Usage

from datasets import load_dataset

ds = load_dataset("juliensimon/neo-close-approaches", split="train")
df = ds.to_pandas()

# Upcoming close approaches sorted by distance
upcoming = df[df["close_approach_date"] > "2025-01-01"].sort_values("distance_au")

# Potentially hazardous approaches
pha = df[df["is_pha"] == True].sort_values("distance_au")

# Large objects (estimated > 100m) passing within 10 Lunar Distances
big_close = df[
    (df["estimated_diameter_max_m"] > 100) &
    (df["distance_ld"] < 10)
]

# Approaches per decade
df["decade"] = (df["close_approach_date"].dt.year // 10) * 10
by_decade = df.groupby("decade").size()

Data source

NASA JPL CNEOS SBDB Close-Approach Data API. Orbits are continuously refined as new astrometric observations are collected by surveys like Catalina Sky Survey, Pan-STARRS, and ATLAS.

Update schedule

Daily at 10:00 UTC via GitHub Actions.

Related datasets

• space-track-satcat — Full NORAD satellite catalog
• space-track-tle-history — 232M historical TLE records
• space-launch-log — Global launch history from GCAT
• starlink-fleet-data — Daily Starlink constellation snapshots

Pipeline

Source code: juliensimon/space-datasets

Support

If you find this dataset useful, please give it a ❤️ on the dataset page and share feedback in the Community tab! Also consider giving a ⭐️ to the space-datasets repo.

Citation

@dataset{neo_close_approaches,
  author = {Simon, Julien},
  title = {NEO Close Approaches},
  year = {2026},
  publisher = {Hugging Face},
  url = {https://huggingface.co/datasets/juliensimon/neo-close-approaches},
  note = {Based on NASA/JPL Center for Near Earth Object Studies (CNEOS) data via the SBDB Close-Approach API}
}

License

CC-BY-4.0