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| ENDEAVOUR DOCKS WITH THE STATION |
| Overview |
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Endeavour’s rendezvous with the International Space Station actually begins with its precisely timed launch from the Kennedy Space Center in Florida. The Shuttle will rendezvous with the Station either on Flight Day 3 or 4, based on the time and date of launch, and at a time based on ISS-orbiter phasing. The primary pre-rendezvous activities include a check-out of the orbiter's remote manipulator system, or robot arm, (RMS), the extravehicular mobility units (EMUs), the Ku-band antenna, the orbiter docking system (ODS), and the ground command system. Final rendezvous operations begin about three hours prior to Endeavour’s docking with the ISS. Endeavour will approach the ISS from below, in what is referred to as a plus-R bar approach, to minimize the effects of jet thruster firings on the station and its solar arrays. About 40 minutes prior to the terminal initiation burn (Ti burn) when Endeavour moves within 135,000 feet of the station, the Shuttle’s rendezvous radar system is activated to provide supplemental navigation information. Prior to initiating the Ti burn, the crew will power on the ODS and activate Endeavour’s docking lights. A series of course correction burns will bring Endeavour to a point almost directly below and behind the International Space Station, at which point Commander Brent Jett initiates the manual portion of his approach to the ISS. Endeavour will intercept the R-bar at a distance of about 600 feet below the station. Jett will slowly move Endeavour to a point about 500 feet below the station before performing a 180 degree yaw maneuver to position Endeavour in a “tail forward” attitude for the final approach and docking. As Jett gently moves Endeavour toward the station, the Shuttle will stationkeep at distances of 170 feet and 30 feet before initiating the final approach and docking. Solar arrays on the Zarya and Zvezda modules will be feathered (or positioned) and locked during the 170 foot stationkeeping phase. Feathering is initiated by a command to reposition and hold each beta (and alpha) joint at a predetermined angle, which will limit the induced loads. Endeavour will dock with Pressurized Mating Adapter (PMA) 3 located on the nadir port of the Unity module. This new docking port was installed during the STS-92 mission in October. At initial contact and capture, the ISS will automatically switch to free drift, and Endeavour will go to free drift to avoid imposing excessive loads on the orbiter docking system (ODS). After capture, light-emitting diodes (LEDs) on PMA-3 will blink confirming the ISS is in free drift. The crew will be able to see the red indicators through the overhead window on Endeavour’s aft flight deck and verify that the ISS is in the free-drift mode before beginning the automatic rigidization and retraction process and closure of the capture latches between the two docking hatches. Once a “hard dock” is confirmed, the ODS will be deactivated, Zvezda and Zarya solar arrays will resume sun tracking, and the Endeavour-ISS complex will maneuver to the mated attitude. Docked Operations After the orbiter docks with the ISS, the crew will enter PMA-3 to install ground straps, and perform a pressure leak check and center disk removal to prepare for their later entry into the Unity module of the ISS for supply transfer. Mission Specialists Joe Tanner and Carlos Noriega will perform two scheduled space walks, or EVAs, during docked operations to install the P6 photovoltaic solar array for power distribution to the Station, relocate the S-band antenna installed during the STS-92 mission in October, peform early external thermal control system connections, and complete some “get ahead” tasks for the STS-98/5A mission in February. Undocking and Flyaround Before Endeavour undocks and departs on Flight Day 8, ground personnel will update the ISS vector and mass data. These data include attitude departure maneuver data, attitude hold data, post-departure mass properties, and post-departure attitude maneuver data. A navigation platform alignment will be performed. Zvezda and Zarya solar arrays will be commanded to stop sun tracking and will be feathered to the edge-on position. In preparation for undocking from the ISS, the STS-97 crew will once again power-up the orbiter docking system, turn on the Shuttle's docking lights, terminate all OIU operations, and enable the Shuttle’s navigational aids. Following its undocking from the ISS, Pilot Mike Bloomfield will slowly back Endeavour away from the ISS at the rate of about 1/10th of a foot-per-second before beginning a flyaround of ISS. Endeavour will move to a point about 450 feet below the station before beginning a tail-forward circuit of the station, arriving once again at a position approximately 600 feet below the ISS. At that point, Bloomfield will perform a final separation burn to move Endeavour away from the station. Once Endeavour is about 30 feet away from the station, the Expedition One crew will activate the station’s attitude control systems. The Zvezda module will then maneuver station to is normal orientation for orbital operations, the solar arrays will be commanded to resume sun tracking, and the station docking system and lights will be deactivated. |
Editorial/Technical Comments: ShuttlePresskit
