NEO Radar — Real orbital mechanics for Near-Earth Objects

NEO Radar

Open Radar

Data · JPL Horizons

MAY · 2026

139 asteroids are passing through

Earth's neighborhood this month.

NEO Radar is a real orbital-mechanics engine for tracking Near-Earth Objects.<br>47 high-fidelity objects with full RK4 N-body dynamics, plus 41,812 MPC catalog<br>asteroids with real positions — all 8 planets simulated. Click any asteroid for<br>a complete physical dossier.

Open Radar

How it works

Next Close Approach

0.71lunar distances

2025 PT5 · in 2 d 14 h 22 m

2024 YR4

a=1.18 AU · e=0.66

Monitor<br>0.94 LD

Apophis

99942 · NEA, Aten

Caution<br>31,800 km

2025 QV1

a=0.93 AU · e=0.41

Safe<br>2.4 LD

View All 41,859 Tracked

Upcoming Close Approaches · Live

Updated 6h ago · NASA NeoWs

Engineering<br>Real physics. Not approximations.

Every trajectory in NEO Radar is integrated from JPL Horizons ephemeris with full<br>gravitational perturbation from the outer planets. The numbers you see are the<br>numbers a mission planner would see.

E₀ → E₁ → E₂ → E₃ ε

01 / Kepler

Solves Kepler's equation, not lookup tables.

Mean anomaly to eccentric anomaly via Newton-Raphson with adaptive seed,<br>converging to 1×10⁻¹² in under four iterations even for high-eccentricity orbits.

M → E → ν<br>ε = 1e-12

+ Δv

02 / Perturbation

Jupiter and Saturn pulled, and you see the pull.

Toggle outer-planet gravity on or off. The uncertainty cone widens visibly<br>on Jupiter-flyby trajectories — what mission planners call the keyhole problem.

N-body RK4<br>Adaptive Δt<br>All 8 planets

1999

2025

2050

26 yr arc

σ = 412 km

03 / Data

JPL Horizons ephemeris, locally cached.

Pulled directly from JPL Horizons and pinned to disk for instant access. Observation<br>arcs and uncertainty parameters travel with every object — no approximations, no drift.

NASA NeoWs<br>SPICE kernels<br>Local cache

Trust<br>How accurate is it?

We benchmark every NEO Radar trajectory against JPL Horizons ephemeris over a<br>50-year window. Where simplified two-body models drift by tens of thousands of<br>kilometers, NEO Radar stays inside the actual uncertainty cone.

Position accuracy is computed as RMS deviation from JPL ground truth across the<br>same 50-year window for the 47 high-fidelity objects.

NEO Radar

412 km

Kepler-only

18,400 km

2-body sim

112,000 km

Position RMS · 50 yr

412 km

Catalog Objects

41,859

Integrator Order

RK4

Adaptive Δt

10⁻³–10⁰ d