NASA had its plate quite full by December 2006.
The Constellation program’s needs would require substantial re-configuring of Launch Complex 39-B for the Ares 1 launch test.
STS-116 with Shuttle Discovery would be the last operational flight to leave from 39-B, although the refits to the pad would not affect the Launch on Need contingency use of the pad for Safe Haven rescues leaving for the International Space Station or for an expected final Hubble Servicing mission.
Coincidentally, like the final Apollo lunar landing mission in 1972, the final Shuttle launch from 39-B was a nighttime launch.
The ISS central configuration would change further over the next two assemblies. The P5 Truss would be taken up on STS-116, along with some resupplies, a SPACEHAB module used for carrying station resupplies, and a new Expedition crew member. This final inner truss would allow the installation of the second port side solar array at a later date, moving one of the two arrays that had rested atop the Z1 Truss for several years.
Among others aboard STS-116 was astronaut Sunita “Suni” Williams, on her first spaceflight, to become part of the Expedition 14 crew. As of this writing, Williams is one of the few Shuttle-era astronauts still active at NASA since the program ended in 2011.
Williams would replace ESA astronaut Thomas Reiter on the ISS. Also aboard Shuttle Discovery was ESA astronaut Christer Fuglesang, who would make a spacewalk as part of the ISS assembly, as well as conducting ESA’s CELSIUS experiments.
Fuglesang would become the first Swedish astronaut. With Reiter returning with Fuglesang at mission’s end, this would be the first time that two ESA astronauts were in space together.
After a launch scrub due to unacceptable clouds on December 7, the mission began on December 12.
On flight day 3, after the usual ISS checks of the Orbiter’s thermal protection system as the vehicle made its pitch maneuver for additional inspections, Discovery docked with the station. The crew had made an earlier inspection themselves a day earlier en route to the ISS.
Flight day 3 ended with the removal of the P5 truss from the payload bay and transfer to the Canadarm2 of the station. The station’s arm will aid in the truss installation during the first of three scheduled EVAs.
On EVA 1 on flight day 4, astronauts Robert Curbeam and ESA astronaut Fuglesang completed the installation of the P5 truss to the end of the P4 truss with help from astronaut Joan Higginbotham, who operated Canadarm2 to guide the truss into position. Radiators that were temporarily near the P4/P5 trusses were moved again to make room for the last port solar array for a later transfer.
Flight day 5 was a frustrating day for all involved with the scrubbed retraction of the P6 solar array atop the Z1 truss. The array’s retraction did not return to its accordion-like state, with kinks that appeared over several retraction attempts.
Flight day 6 began EVA 2, again with Curbeam and Fuglesang. The 5 hour spacewalk was all about the extensive rewiring of the station’s electrical system from the S0 truss in its permanent configuration for the port solar arrays, once the arrays were re-located on the port truss. The spacewalk was lengthy as the station crews had to power down large areas of the electrical system prior to the re-wiring, and then re-energize and test the new configuration.
The station and Orbiter crews had a light day of work on flight day 7. A passive but unsuccessful attempt to jostle the problematic P6 array into retracting was made that day with an unusual procedure: Human exercising. Thomas Reiter huffed and puffed on the station’s exercise system, which was known to shake the solar arrays.
The third and final EVA brought Curbeam outside once more, this time with Suni Williams on her first spacewalk. Their EVA was very similar to EVA 2’s re-configuration of electrical cabling on S0. Some success was made by the team to retract a bit more of the P6 array, leaving 35% left to to retract.
Mission Control and the orbiting crews agreed to plan a fourth unscheduled EVA to work the P6 array retraction once more. Astronauts Curbeam and Fuglesang were outside once more on a 6 hour walk on flight day 9. The tedious retraction was finally done.
Discovery departed the station on December 19, flight day 11.
Over the next three days before they would land on December 22, the crew would launch the MEPSI (Microelectromechanical System-Based PICOSAT Inspector), RAFT (Radar Fence Transponder) and ANDE (Atmospheric Neutral Density Experiment) microsats for the US Naval Research Laboratory.
The unplanned EVA 4 taxed Discovery’s onboard consumables. Docked or not, few Shuttle missions could last more than 15 days. The Orbiter would deorbit on flight day 14 unless all three of its prime landing sites (The Kennedy Space Center, Edwards Air Force Base, and White Sands Missile Range) were unsafe to use.
The KSC runway was waved off at first, with rain and clouds in the area. Edwards was also off the table due to high winds. That left White Sands, which hadn’t been used since the third STS mission in 1982.
Mission Control decided to watch KSC to see if things would clear up enough for a landing.
A window of opportunity appeared, and Discovery returned by the late afternoon of December 22.
The next assembly mission to the station, planned in the summer of 2007 with Atlantis, would be no less challenging. The ISS would form its first H-configuration with the arrival and installation of its third solar array.
Next mission: Assembly 13A.
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