Aerocapture Corridor Margin

Audit a predicted entry-angle uncertainty band against a supplied aerocapture corridor; no atmosphere-specific corridor is embedded.

Description

An entry corridor can be checked against a predicted angle's entire uncertainty band.

An entry corridor can be checked against a predicted angle's entire uncertainty band. A central estimate inside the corridor can still leave its lower or upper bound outside.^[1]

Audit a predicted entry-angle uncertainty band against a supplied aerocapture corridor; no atmosphere-specific corridor is embedded.

When to use Aerocapture Corridor Margin

Use this tool to audit a predicted entry-angle uncertainty band against a supplied aerocapture corridor; no atmosphere-specific corridor is embedded.

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 Aerocapture Corridor Margin 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 minimumEntryAngleDegrees, maximumEntryAngleDegrees, predictedEntryAngleDegrees, uncertaintyHalfWidthDegrees using the field table and calculation rules, then run the tool.
Read uncertaintyLowerDegrees, uncertaintyUpperDegrees, worstCorridorMarginDegrees, uncertaintyBandInsideCorridor. 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
minimumEntryAngleDegrees	Minimum entry angle degrees	number	Required
maximumEntryAngleDegrees	Maximum entry angle degrees	number	Required
predictedEntryAngleDegrees	Predicted entry angle degrees	number	Required
uncertaintyHalfWidthDegrees	Uncertainty half width degrees	number	Required

Enter ordered corridor angles within [−90,0] degrees, a finite predicted angle and nonnegative uncertainty half-width. The tool returns both band endpoints, the smaller signed boundary margin and an inclusive inside flag. Margin zero means the band touches a boundary; a negative value means it exceeds at least one boundary.

worstMargin = min(predicted−halfWidth−minimum, maximum−predicted−halfWidth)

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
uncertaintyLowerDegrees	Uncertainty lower degrees	number
uncertaintyUpperDegrees	Uncertainty upper degrees	number
worstCorridorMarginDegrees	Worst corridor margin degrees	number
uncertaintyBandInsideCorridor	Uncertainty band inside corridor	boolean

json

{
  "input": {
    "minimumEntryAngleDegrees": -8,
    "maximumEntryAngleDegrees": -5,
    "predictedEntryAngleDegrees": -6,
    "uncertaintyHalfWidthDegrees": 0.5
  },
  "output": {
    "uncertaintyLowerDegrees": -6.5,
    "uncertaintyUpperDegrees": -5.5,
    "worstCorridorMarginDegrees": 0.5,
    "uncertaintyBandInsideCorridor": true
  }
}

Limitations and assumptions

The corridor and uncertainty are supplied, not calculated from an atmosphere or vehicle. This does not establish flight safety, a probability distribution or a heating/trajectory solution.

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. A successfully returned false flag is an evaluated outcome; its meaning is explained above.

Alternative or Complementary methods

Use Exponential Entry Peak Deceleration: Evaluate the constant-flight-path, drag-only Allen–Eggers exponential-atmosphere peak-deceleration approximation; lift and changing entry angle are neglected. For a complementary task, use Circular Deorbit Interface Burn: Calculate an impulsive retrograde burn from a circular orbit to a supplied interface periapsis in consistent km/s units; no atmospheric landing path is inferred.

References

Aerocapture Corridor Margin — tool.io

Similar or alternative tools

Exponential Entry Peak Deceleration
Evaluate the constant-flight-path, drag-only Allen–Eggers exponential-atmosphere peak-deceleration approximation; lift and changing entry angle are neglected.
Circular Deorbit Interface Burn
Calculate an impulsive retrograde burn from a circular orbit to a supplied interface periapsis in consistent km/s units; no atmospheric landing path is inferred.