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Hyperbolic Orbit Escape Velocity & C3 Energy Calculator

To leave the gravitational sphere of influence of a planet, a spacecraft must exceed local escape velocity.

Radius from planet center at trans-injection engine cutoff (e.g. 200 km LEO = 6578 km).

Inertial velocity magnitude at burnout (> v_escape).

Gravitational constant of departure planet (Earth = 398600.44).

Calculated Result
2.961 km/s

Hyperbolic Excess Velocity (v_inf)

Local Escape Velocity

11.009 km/s

Characteristic Energy (C3)

8.77 km²/s²

Trajectory Eccentricity

1.145

Calculation Breakdown

  1. Local Escape Speedv_esc = √(2μ / r) = √(2·398600.44 / 6578) = 11.009 km/s
  2. Excess Velocity Energyv_∞ = √(v² - v_esc²) = √(11.4² - 11.009²) = 2.961 km/s

What Is the Hyperbolic Orbit Escape Velocity & C3 Energy Calculator?

A hyperbolic trajectory is an open orbit where an object has enough mechanical energy to escape a central gravitational body completely.

How Does the Hyperbolic Orbit Escape Velocity & C3 Energy Calculator Work?

Uses specific orbital energy conservation to determine asymptotic velocity at infinite separation.

Hyperbolic Orbit Escape Velocity & C3 Energy Calculator Formula & Variables

The core mathematical equation utilized by this calculator is expressed as:

v_{ ext{esc}} = sqrt{ rac{2mu}{r}}, quad v_infty = sqrt{v^2 - v_{ ext{esc}}^2}, quad C_3 = v_infty^2

Conservation of orbital specific energy for unbound hyperbolic trajectories.

How to Use the Hyperbolic Orbit Escape Velocity & C3 Energy Calculator

  1. Input burnout radius from planetary center and burnout velocity magnitude.

Step-by-Step Example Calculation

Trans-Mars Injection Burnout

Input Values:

burnBurnoutRadiusKm:6578
burnoutVelocityKmS:11.4
standardGravParamKm3S2:398600.44
Worked Steps: Escape velocity = 11.01 km/s, yielding hyperbolic excess v_∞ = 2.96 km/s and C3 = 8.76 km²/s².

Understanding Your Result

Shows local escape speed, hyperbolic excess velocity (v_inf), and C3 launch energy required by interplanetary launch vehicles.

Factors That Affect the Result

  • Lower parking orbit altitudes provide an Oberth effect advantage during departure burns.

When Should You Use This Calculator?

  • Interplanetary mission design (Mars, Jupiter missions), solar system escape analysis, and launch vehicle capability sizing.

Assumptions & Limitations

  • Patched-conic approximation; ignores third-body solar and lunar gravitational perturbations.

Frequently Asked Questions

Calculation Accuracy & Reference Note

Standard vis-viva hyperbolic orbital energy relation.

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