fama asteroid calculator

What is the FAMA asteroid calculator?

The FAMA asteroid calculator is a practical screening tool for estimating how energetic an asteroid encounter could be, then translating that estimate into a simple 0–100 risk indicator. It is designed for educational use, scenario planning, and science communication—not official threat assessment.

FAMA combines four components:

• Frequency (F): derived from impact probability.
• Approach (A): based on closest approach distance.
• Magnitude (M): based on kinetic energy (TNT equivalent).
• Angle (A): entry angle modifier, where steeper atmospheric entry tends to preserve more impact energy.

How calculations are made

1) Mass estimate from diameter and density

We model the asteroid as a sphere:

Mass = (4/3) × π × r³ × density

where r is radius in meters and density is in kg/m³.

2) Kinetic energy estimate

Once mass is known, impact energy is estimated by:

Energy = 0.5 × mass × velocity²

with velocity converted from km/s to m/s. The calculator also converts joules into megatons of TNT for easier interpretation.

3) FAMA score composition

Each of the four dimensions contributes up to 25 points. The final score is:

FAMA Score = F + A + M + A(ngle)

This creates a normalized 0–100 score that can be interpreted quickly:

• 0–20: Low
• 20–40: Guarded
• 40–60: Elevated
• 60–80: High
• 80–100: Severe

How to use this tool effectively

Start with the best available observational estimates. Diameter and velocity often dominate the final energy output, so even small changes in those inputs can move the risk class significantly.

• Use a realistic density range for asteroid type (stony, metallic, or carbonaceous).
• Set approach distance to 0 km only for explicit impact scenarios.
• Run multiple scenarios (best case, nominal, worst case) rather than a single point estimate.
• Interpret outputs comparatively, not as precise predictions.

Important limitations

Real asteroid hazard analysis is far more complex and includes orbital uncertainty propagation, atmospheric breakup physics, impact location, ocean coupling, local geology, and secondary effects. This page is a transparent approximation intended to make core concepts understandable.

For formal monitoring, follow agencies such as NASA CNEOS and ESA’s Near-Earth Object Coordination Centre.

Bottom line

The fama asteroid calculator helps you turn raw asteroid inputs into a readable energy estimate and a simple priority signal. It is especially useful for educational demos, tabletop planning, and quick comparison between candidate objects.