Aerobraking Geometric Pass Count

Estimate passes under a supplied constant fractional period reduction; atmospheric and trajectory evolution are not inferred.

Description

A constant fractional period reduction compounds over successive aerobraking passes.

A constant fractional period reduction compounds over successive aerobraking passes. Estimating the count requires logarithmic inversion rather than dividing the total period change by one fixed decrement.^[1]

Estimate passes under a supplied constant fractional period reduction; atmospheric and trajectory evolution are not inferred.

When to use Aerobraking Geometric Pass Count

Use this tool to estimate passes under a supplied constant fractional period reduction; atmospheric and trajectory evolution are not inferred.

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 Aerobraking Geometric Pass Count 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 initialPeriod, targetPeriod, periodReductionFractionPerPass, maximumPasses using the field table and calculation rules, then run the tool.
Read requiredPasses, projectedFinalPeriod. 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
initialPeriod	Initial period	number	Required
targetPeriod	Target period	number	Required
periodReductionFractionPerPass	Period reduction fraction per pass	number	Required
maximumPasses	Maximum passes	integer	Required

Enter positive initial and target periods with target no greater than initial, a reduction fraction strictly between 0 and 1, and positive integer maximumPasses. The tool computes the ceiling with a small floating-point boundary adjustment, errors if the count exceeds the supplied bound and returns count plus projected final period. Equal periods require zero passes.

requiredPasses ≈ ceil[log(target/initial)/log(1−fraction)]; final = initial(1−fraction)^passes

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

Output field	Meaning	Value type
requiredPasses	Required passes	number
projectedFinalPeriod	Projected final period	number

json

{
  "input": {
    "initialPeriod": 100,
    "targetPeriod": 25,
    "periodReductionFractionPerPass": 0.5,
    "maximumPasses": 10
  },
  "output": {
    "requiredPasses": 2,
    "projectedFinalPeriod": 25
  }
}

Limitations and assumptions

The reduction is a fixed supplied model. Atmospheric variability, changing trajectory and campaign scheduling are absent; the numerical ceiling adjustment is not a physical uncertainty allowance.

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 Drag Stationkeeping Impulse: Estimate drag make-up impulse from a constant environment and supplied orbit duty factor; density variation and maneuver losses are not modeled. For a complementary task, use Keplerian Orbital Period: Compute a two-body elliptic orbital period from semimajor axis and total gravitational parameter, not a fixed planetary lookup.

References

Aerobraking Geometric Pass Count — tool.io

Similar or alternative tools

Drag Stationkeeping Impulse
Estimate drag make-up impulse from a constant environment and supplied orbit duty factor; density variation and maneuver losses are not modeled.
Keplerian Orbital Period
Compute a two-body elliptic orbital period from semimajor axis and total gravitational parameter, not a fixed planetary lookup.