Drift¶

Script Type: WsfDriftManeuver

maneuver drift
   Common Maneuver Commands …
   drift_rate ...
   delta_time ...
   maximum_delta_time ...
   maximum_delta_v ...
   optimize_time ...
   optimize_delta_v ...
   optimize_cost ...
   tolerance ...
end_maneuver

A drift maneuver will transfer the executing platform from an initial circular orbit to a final circular orbit with a relative drift rate. Because these two orbits do not intersect, the transfer is made via an intermediate orbit similar to those in targeting-class maneuvers (e.g., Rendezvous). As such, this maneuver also has options for specifying details of the transfer, allowing the user to set time or delta-V related constraints, and to specify optimization for time taken, or delta-V cost.

Note

Only the constraints relative_time, ascending_node, descending_node, eclipse_entry or eclipse_exit are supported for this maneuver.

drift_rate <angle-rate-value>¶: Specify the rate of drift between the initial and final orbits.

delta_time <time-value>¶: The desired time past the current time for execution of the maneuver. No Optimizations are performed.

Note

One of delta_time, maximum_delta_time or maximum_delta_v must be set. If maximum_delta_time is not set and maximum_delta_v is set, maximum_delta_time will be set to one orbital period of the target platform.

maximum_delta_time <time-value>¶: The maximum time after the current time to be considered for execution of the maneuver. Optimizations in time will occur between the time of the constraint and the provided time.

maximum_delta_v <speed-value>¶: The maximum delta_v to be considered for execution of the maneuver. Optimizations in time to find minimum delta-v will occur between the time of the constraint and any time limit set by maximum_delta_time.

Note

This value is constrained to be less than or equal to the delta-v specified in the maneuvering model.

optimize_time¶: Optimize the targeting solution such that it executes at the earliest possible time. This optimization is also constrained by the maximum_delta_v value, if provided.

optimize_delta_v¶: Optimize the targeting solution such that it executes at a time that minimizes total delta-v expended.

optimize_cost <cost_type> …¶

Optimize the targeting solution such that the specified cost is minimized. The available cost functions are:

blended <A value> <B value> <C value>

This cost function depends on the transfer duration, $\Delta t$ , and the change in velocity, $\Delta V$ as follows:

$g(\Delta t, \Delta V) = A \Delta t + B \Delta V + C \Delta t \Delta V$ .

The values of $A$ , $B$ , and $C$ are provided as additional real arguments after the specification of the ‘blended’ cost.