Evolution: Figure-8

This impulse navigation evolution involves maneuvering the vessel  along a “figure eight” loop around two planets.

Candidates must maneuver the vessel from a central target area (starting at point 1 on the diagram) towards one planet and completing a radial traversal it (point 2). Candidates must then maneuver through the central target area towards the opposite planet, performing a radial traversal in the other direction (point 3) before maneuvering and coming to all stop within the central target area (point 4 on the diagram).

Skills

The evolution is intended to provide training and competency evaluation on the following impulse navigation skills:

  • Executing radial traversals
  • Using the IBC to calculate intercept headings
  • Using the IBC to guide maneuver timing
  • Deceleration to a defined point

Proving Course

The proving course for this evolution consists of two planets, the grid locations of which will be supplied to the evolution participants, along with the grid position of the starting point (which is midway between the two planets).

Participants will be told which order the planets should be traversed and in which direction the first traversal should take place (the second traversal will always be in the opposite direction).

The evolution ends inside a Central Target Area (CTA) 200 GU’s squared, centred on the starting point. 

Example Course

The example evolution uses the following proving course from a starting point of X:195 Y:10989. Vessel begins with a heading of 000.

Planet 1: Sol2 Planet 2: Sol4
Grid Pos X 2134 Grid Pos X -1745
Grid Pos Y 6877 Grid Pos Y 15100
Traversal direction Starboard Traversal direction Port
Traversal radius 100GU Traversal radius 100GU

Evolution Plan

  1. Get the vessel underway.
  2. Use the Intercept Bearing Calculator (IBC) to calculate bearing to the radial traversal intercept point for the first planet.
  3. Adjust heading to the intercept point.
  4. At some point during cruise towards the planet adjust the IBC to the planet's grid location. This will allow the IBC to be used as a guide to when the planet is abeam.
  5. Use the Held Bearing Calculator (HBC) to calculate the held bearing required for the radial traversal.
  6. Set the bearing. The sensitivity of the input radial can be adjusted to allow an extra decimal point if needed.
  7. As the vessel approaches the planet, prepare to engage the held bearing. To ensure focus on the correct point to engage the held bearing maneuver it is recommended the hold function is engaged in advance.
  8. When the IBC shows the planet is abeam (a bearing of -090), engage the held bearing maneuver.
  9. When the vessel's entry heading has been reversed (+/-180), disengage the maneuver.
  10. Calculate the heading required for the intercept point for a radial traversal of the second planet and adjust. If the sensitivity of the input radial was increased in step 6, it may make bearing selection easier if it is decreased now. 
  11. At some point during cruise towards the planet adjust the IBC to the planet's grid location. This will allow the IBC to be used as a guide to when the planet is abeam.
  12. Calculate and set the held bearing required for radial traversal. (In the example, the speed and radius of the second traversal were the same as the first, so no additional calculation was required).
  13. As the vessel approaches the planet, prepare to engage the held bearing. To ensure focus on the correct point to engage the held bearing maneuver it is recommended the hold function is engaged in advance.
  14. When the IBC shows the planet is abeam (a bearing of -090), engage the held bearing maneuver.
  15. When the vessel's entry heading has been reversed (+/-180), disengage the maneuver.
  16. Use the IBC to adjust heading to the starting point.
  17. When the deceleration distance required for the current speed and thrust is reached, reverse thrust.
  18. All stop.
  19. The vessel should be within the CTA, as indicated by the IBC being within +/-100GU of the starting point.
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