Teardrop¶

Script Type: WsfTeardropManeuver

maneuver teardrop
   Common Maneuver Commands …
   target_platform ...
   radial_offset_at_poca ...
   period ...
   time_to_poca ...
   repetitions ...
   delta_time ...
   maximum_delta_time ...
   maximum_delta_v ...
   optimize_time ...
   optimize_delta_v ...
   optimize_cost ...
   tolerance ...
end_maneuver

Perform a maneuver that brings the executing platform onto an orbit that, relative to the target_platform of the maneuver, appears to have a teardrop shape. The parameters that specify the relative motion are a distance at the point of closest approach (POCA), and the time it takes the executing platform to traverse the teardrop.

In addition to the final relative motion, the executing platform will perform maneuvers similar to a Rendezvous to transfer from its initial orbit to the final teardrop orbit. Because of this transfer, this maneuver also has many options that overlap with Rendezvous.

See Teardrop Orbit for details.

Note

This following conditions cannot be used with this maneuver: ascending_radius, descending_radius, northern_intersection, and southern_intersection.

Commands¶

target_platform <string-value>¶: Specify the platform relative to which the executing platform will perform a Teardrop maneuver.

radial_offset_at_poca <length-value>¶: Specify the distance at the point of closest approach. This distance will be entirely in the radial direction, with a positive value indicating that the teardrop will be above the target_platform. The provided value must be non-zero.

period <time-value>¶: Specify the time taken to execute the teardrop maneuver. This period must be no greater than about 40.6 percent of the orbital period of the target_platform. The period covers from when the executing platform first passes directly under (over) the target, and when it passes under (over) the target for the last time. These times are at half the given period before the point of closest approach and half the period after the point of closest approach.

time_to_poca <time-value>¶: Specify the duration after the executing platform is inserted onto the teardrop orbit at which it reaches the point of closest approach to the target_platform. This value must be greater than half of the specified period.

repetitions <integer-value>¶

Specify the number of times the executing platform should traverse the teardrop. This provided value must be positive.

Default: 1

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.