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| SPARTAN 201-5 Rendezvous & Prox Ops |
| Overview |
| PROXIMITY OPERATIONS SPARTAN rendezvous begins at payload release with Proximity Operations. Immediately following release of the target, the Orbiter will stationkeep (fly in formation) at a distance of 35 feet in an inertial attitude hold while SPARTAN attitude control is verified. SEPARATION Six minutes after release, the crew of Discovery will execute a separation maneuver (SEP1) at a rate of 1fps. The maneuver is designed to clear the Orbiter of the SPARTAN orbital path and to set up the second separation maneuver (SEP2). SEP2 will initiate a retrograde separation to place Discovery ahead of the target on the same velocity vector. A phasing maneuver (NC1) will then set up the two spacecraft 5-6 miles apart - well within range of the Orbiters RF communication system. At this distance, SPARTAN controllers on the ground will command the spacecraft via the Orbiter Payload Interrogator for the start of TEXAS operations. After 4 orbits of stationkeeping, a second phasing maneuver (NC2) will start Discovery on a slow separation to a distance of 30 nautical miles ahead of the SPARTAN, where NC3 will establish stationkeeping for several orbits of additional SPARTAN deployed science operations. RENDEZVOUS At completion of SPARTAN autonomous operations, a final phasing maneuver (NC4) will initiate a 2-orbit rendezvous profile placing Discovery behind and slightly below the target for the Terminal Phase of the rendezvous. TERMINAL PHASE Terminal Phase Initiation will begin at a distance of 8.2 nautical miles behind and below the target with a 9.4 fps OMS maneuver (Ti) which will set up Discovery for an "R-BAR" (underneath) final approach for the capture of SPARTAN. |
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| History/Background |
| This particular rendezvous profile utilizes the "ORBT" approach - one which was developed for the Shuttle/Mir rendezvous and docking missions of the ISS Phase One Program. It is an "R-BAR" approach, which means the Orbiter approaches the rendezvous target from below and translates up the radial vector (imaginary line radiating from the center of the Earth to the orbiting target). This particular "R-BAR" technique optimizes propellant usage over previous preferred techniques, and is the current choice in planning for missions to the International Space Station. NOTE: More information about rendezvous maneuvers and terms can be found in the Shuttle Reference Data section. |
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Editorial Contact Ed Campion
Technical Contact USA Web Master
