Conic Flight Path Angle
Compute the conic flight-path angle with a physical positive-radius anomaly constraint for elliptic, parabolic, or hyperbolic eccentricity.
Description
Flight-path angle measures the velocity's tilt relative to the local transverse direction.
Flight-path angle measures the velocity's tilt relative to the local transverse direction. Its sign follows inward or outward radial motion under the chosen true-anomaly convention.1
Compute the conic flight-path angle with a physical positive-radius anomaly constraint for elliptic, parabolic, or hyperbolic eccentricity.
When to use Conic Flight Path Angle
Use this tool to compute the conic flight-path angle with a physical positive-radius anomaly constraint for elliptic, parabolic, or hyperbolic eccentricity.
Prepare the orbital state or model parameters in one reference frame. Confirm compatible distance/time units and the stated angular and gravitational-parameter conventions.
How to use Conic Flight Path Angle and understand its results
- Prepare the orbital state or model parameters in one reference frame. Confirm compatible distance/time units and the stated angular and gravitational-parameter conventions.
- Enter orbitalEccentricity, trueAnomalyDegrees using the field table and calculation rules, then run the tool.
- Read flightPathAngleDegrees. The explanation below defines the units, signs, ordering and any flags or placeholder values.
- If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.
| Input field | Meaning | Value type; see rules below | Requirement |
|---|---|---|---|
| orbitalEccentricity | Orbital eccentricity | number | Required |
| trueAnomalyDegrees | True anomaly degrees | number | Required |
Enter nonnegative eccentricity and finite true anomaly in degrees. The factor 1+e cosν must be strictly positive, excluding inaccessible or asymptotic conic positions. The tool uses atan2 and returns a signed degree angle. Elliptic, parabolic and hyperbolic eccentricities are accepted when that radius condition holds.
flightPathAngle = atan2(e sinν,1+e cosν) in degrees Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| flightPathAngleDegrees | Flight path angle degrees | number |
{
"input": {
"orbitalEccentricity": 0.5,
"trueAnomalyDegrees": 90
},
"output": {
"flightPathAngleDegrees": 26.56505117707799
}
}Limitations and assumptions
It does not return speed, position or an entry trajectory. Periapsis distance and gravitational parameter are absent, and physically meaningful anomaly conventions must be supplied.
Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.
Alternative or Complementary methods
Use Hyperbolic Anomaly Chain: Convert a physically accessible signed true anomaly to hyperbolic anomaly H and mean anomaly e·sinh(H)−H, both dimensionless. For a complementary task, use Elliptic Semilatus Rectum: Calculate the elliptic semilatus rectum from semimajor axis and eccentricity rather than measured apsis radii.
References
-
Conic Flight Path Angle — tool.io
Similar or alternative tools
- Hyperbolic Anomaly Chain
Convert a physically accessible signed true anomaly to hyperbolic anomaly H and mean anomaly e·sinh(H)−H, both dimensionless.
- Elliptic Semilatus Rectum
Calculate the elliptic semilatus rectum from semimajor axis and eccentricity rather than measured apsis radii.