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Calcimator

Launch Window Calculator

Calculate synodic period, optimal wait time, and transfer time for interplanetary or orbital launch windows.

Inputs

days
days
°
°

Results

Synodic Period

779.88 days

Wait Time to Launch

4.01 days

Transfer Time263.06 days
Total Mission Time267.07 days
How to Use This Calculator
  1. Enter the orbital periods (days) of the origin body (Earth) and target body (Mars, Venus, etc.).
  2. Set the current phase angle between the two bodies and the required transfer angle.
  3. Review synodic period (days), wait time until next launch window, and Hohmann transfer time.
  4. Use the total mission time to plan crew consumables, power budgets, and mission duration constraints.

How the result changes with Origin Orbital Period

Origin Orbital PeriodSynodic PeriodWait Time to Launch
10,001737.67 days377.39 days
35,001700.75 days426.84 days
65,000694.34 days365.08 days
90,000692.28 days431.51 days

What each input means

Origin Orbital Period
Orbital period of the departure body (e.g., Earth = 365.25 days).
Target Orbital Period
Orbital period of the destination body (e.g., Mars = 687 days).
Current Phase Angle
Current angular separation between origin and target bodies in degrees.
Transfer Angle
Angular sweep of the transfer orbit. 180° for a standard Hohmann transfer.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Origin Orbital Period = 365.25, Target Orbital Period = 687, Current Phase Angle = 44, Transfer Angle = 180 = 4 input(s) provided
  2. Calculate Synodic Period
    Synodic Period
    779.88 = 779.88
  3. Calculate Wait Time to Launch
    Wait Time to Launch
    4.01 = 4.01
  4. Calculate Transfer Time
    Transfer Time
    263.06 = 263.06
  5. Calculate Total Mission Time
    Total Mission Time
    267.07 = 267.07

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