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This scenario shows a few simple rendezvous and proximity operations
maneuvers in Lunar Orbit using the STK/Astrogator module. Two spacecraft, represented by models
of the Apollo Command Service Module (CSM) and Lunar Excursion Module
(LEM), start off docked in a 110
km, circular Lunar orbit. After an
hour, the CSM backs away 200 meters from the LEM along the ‘VBar’ (the
inertial velocity vector of the LEM).
The CSM stays on the VBar, rather than drifting off of it (as
would be the natural tendency) by using STK/Astrogator auto-sequences
that trigger adjustment maneuvers whenever the vehicle strays from the
VBar.
After a 20 minute coast, the CSM
transfers to an intermediate elliptical orbit to move back 1 km in the
orbit, and then transfers back to the original orbit to maintain
position. (These sorts of
transitions are often referred to as Clohessy-Wiltshire, or CW
‘Hops’). The CSM holds there for
20 minutes and then makes another CW hop to 10 km back. Next the CSM ‘Hops’ back to the -2 km
point, and then drives in along the VBar to a final docking using
Astrogator auto-sequences. For
more information about this and other Astrogator scenarios, please visit http://www.astrogatorsguild.com.
To watch this sequence of events unfold, click Start in the animation
tool bar.
STK 
STK/Astrogator 
STK/Attitude 
STK/Advanced Visualization Option


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