Function ignition_altitude_kernel 

pub fn ignition_altitude_kernel<R>(
    speed: Speed<R>,
    thrust_acceleration: Acceleration<R>,
    gravity: Acceleration<R>,
    margin: Length<R>,
) -> Result<Length<R>, PhysicsError>
where
    R: RealField + FromPrimitive,

Ignition altitude for a constant-thrust vertical stopping burn

$$ h_{ign} = \frac{v^2}{2,(a_T - g)} + h_{margin} $$

the stopping distance against the net deceleration a_T − g, plus the caller-supplied margin. The margin is an input by design: downstream it is sized from the weather-dispersion table’s navigation-drift row, which is not this crate’s business.

Arguments

• speed — descent speed at ignition v (m/s, ≥ 0).
• thrust_acceleration — thrust acceleration a_T = T/m (m/s², must exceed gravity).
• gravity — local gravitational acceleration g (m/s², > 0).
• margin — additive altitude margin h_margin (m, ≥ 0).

References

• Closed-form constant-acceleration kinematics (see stopping_distance_kernel).