How To...

Define a Finite Maneuver from an Impulsive Maneuver with Astrogator

You can convert an Impulsive Maneuver segment to a Finite Maneuver with the same properties, either manually from an Impulsive Maneuver segment's properties window or automatically as an outcome of a Target Sequence.

Astrogator will apply the results of the last run of the Impulsive Maneuver - based upon the parameters (including the engine model and thruster set) you specified for it - in each place where there is a corresponding parameter for the Finite Maneuver, overwriting any settings you may have previously made. The estimated burn duration of the Impulsive Maneuver will be used to define a duration stopping condition for the Finite Maneuver.

About the Finite Maneuver Seeding Process and Data Closed

When a Finite Maneuver is seeded from an Impulsive Maneuver, the follow process is executed by Astrogator:

  1. Impulsive Maneuver data is copied into the Finite Maneuver. Actual values are copied if they were used to define the Impulsive Maneuver; otherwise, default values are copied. This data consists of:
    • Engine model(s)
    • Thruster set
    • Impulsive DeltaV vector (Cartesian and spherical values)
    • DeltaV vector representation choice (Cartesian or spherical)
    • Quaternion values
    • Euler angle values
    • Attitude type
    • Attitude 'override' choice (from the More Options... window)
    • Attitude lead and trail durations
    • Body Constraint Vector (BCV) values, BCV (selected VGT vector), BCV sign
    • Engine direction
    • Attitude file path, time offset, and interpolation order
  2. A single Duration stopping condition - based on the estimated equivalent finite burn duration - is added to the Finite Maneuver's stopping conditions list.
  3. The thrust vector is normalized.

To manually seed a Finite Maneuver, take the following steps:

  1. Select a Maneuver segment in the MCS or create a new one.

  2. Set the Maneuver Type as Impulsive, and then set the other parameters, including the engine model and thruster set, as desired.

  3. Run the MCS.

  4. Select the Maneuver segment and click the Seed Finite From Impulsive button. The Maneuver Type will change to Finite, and the other parameters will be configured as explained in the paragraph above.

To seed a Finite Maneuver using a Target Sequence, take the following steps:

  1. Insert a Change Maneuver Type profile as the first target profile for the Target Sequence. Set the Type to change to field to Impulsive.

  2. Insert a Differential Corrector profile after the Change Maneuver Type profile, and target the Maneuver segment to achieve the desired results.

  3. Insert a Seed Finite Maneuver profile after the Differential Corrector profile.

  4. Insert a second Differential Corrector profile after the Seed Finite Maneuver profile, and target the finite burn to achieve the desired results.

  5. Run the MCS. The Target Sequence will calculate the Maneuver segment as an Impulsive maneuver, targeting the desired results, and then define a Finite maneuver from the calculated Impulsive maneuver; finally, the Target Sequence will use the seeded Finite maneuver to achieve the results specified in the second Differential Corrector profile.

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