ISS 4-Burn Rendezvous Scenario [Last saved 8/2/2007. Scenario originally created by John Carrico ADS and Mike Loucks, SEE]
This scenario was created to demonstrate a 4-burn rendezvous using Astrogator. It contains 3 satellites.
1. ISS_TLE This satellite is an SGP4 propagated satellite that uses the latest TLE for the International Space Station.
2. ISS This is an Astrogator propagated satellite that uses the initial state from the ISS_TLE satellite as its starting point. This was done to allow both the target and chaser spacecraft to use the same propagation scheme. If you don’t do this, when you plot the relative motion trajectory, you will see artifacts from the differences in propagation.
3. 4-Burn This satellite uses the Astrogator Mission Control Sequence (MCS) to perform a rendezvous with the ISS satellite. Specifically it is targeted to put itself 500 meters from the ISS on the V-bar. It uses the Following MCS:
The TargetNodeBiasAngle targeter varies the launch time to get the final Relative RAAN between the 4-burn and the ISS satellite to zero. It has several profiles that achieve this, one of which also targets the DVtoPhaseOrbit maneuver in order to get a specific relative altitude spacing between the 2 satellites (-130 km by default).
The TargetCircular targeter circularizes the satellite in the parking orbit.
Target Final Phase Angle is used to phase the spacecraft in the parking orbit until it is line up properly for a Hohman transfer that will achieve the final orbit altitude with the proper separation.
TargetStop stops us at the final position.
This scenario has some out-of-plane issues that probably should be resolved at some point. It may need to have the launch inclination targeted properly to eliminate this. It is set up now to line up the RAANs, but we assume the inclinations are lined up, which probably is wrong.
Michel E. Loucks
President, Space Mission
Engineer
Space Exploration
Engineering Corp.
360.378.7168
360.317.5527 (cell)