Calculate local escape velocity, compare it with current inertial speed, and add a selectable mission margin. The result is an ideal impulsive speed gap for preliminary trajectory trades.
The margin is applied to the ideal speed gap, not to the entire escape velocity.
A zero speed gap means the entered inertial speed equals or exceeds the local two-body escape threshold. It does not confirm a safe or targeted departure trajectory.
Launch, steering, drag, gravity losses, and direction of the velocity vector are outside this scalar estimate.
At 6,571 km from Earth's center, escape velocity is about 11.01 km/s. From 7.8 km/s, the ideal gap is about 3.21 km/s and becomes about 3.53 km/s with 10% margin.
No. Escape velocity is an ideal local speed; launch losses, staging, rotation, and the spacecraft's current speed change required delta-v.
No. The core escape calculation is a vacuum, two-body estimate. Add a mission margin or a separate loss estimate.
Yes. Enter that body's gravitational parameter and the distance from its center.
Gravitational potential becomes less negative with distance, so less kinetic energy is needed to reach a zero-energy escape path.
No. Use it for early trade studies, then verify with trajectory, propulsion, thermal, and operations analyses.
| Quantity | Definition |
|---|---|
| Escape velocity | Zero-energy local threshold |
| Current speed | Entered inertial speed magnitude |
| Ideal speed gap | Scalar difference to threshold |
| Margin-adjusted gap | Planning allowance on the gap |