STS-115


STS-115 was a Space Shuttle mission to the International Space Station flown by. It was the first assembly mission to the ISS after the Columbia disaster, following the two successful Return to Flight missions, STS-114 and STS-121. STS-115 launched from LC-39B at the Kennedy Space Center on September 9, 2006, at 11:14:55 EDT.
The mission is also referred to as ISS-12A by the ISS program. The mission delivered the second port-side truss segment, a pair of solar arrays, and batteries. A total of three spacewalks were performed, during which the crew connected the systems on the installed trusses, prepared them for deployment, and did other maintenance work on the station.
STS-115 was originally scheduled to launch in April 2003. The Columbia accident in February 2003 pushed the date back to August 27, 2006, which was again moved back for various reasons, including a threat from Tropical Storm Ernesto and the strongest lightning strike to ever hit an occupied shuttle launchpad.

Crew

Crew notes

Canadian Space Agency astronaut MacLean became the first Canadian to operate Canadarm2 and its Mobile Base in space as he was handed a new set of solar arrays from Ferguson and Burbank controlling the original Canadian robotic arm, the Canadarm. MacLean performed a spacewalk, becoming only the second Canadian, after Chris Hadfield to do so.
The mission patch worn on the clothing used by the astronauts of STS-115 was designed by Graham Huber, Peter Hui, and Gigi Lui, three students at York University in Toronto, Ontario, the same university that Steve MacLean attended. The students also designed Steve MacLean's personal patch for this mission.

Mission payloads

The primary payload was the second left-side ITS P3/P4 Truss segment, a pair of solar arrays, and associated batteries.

Mission objectives

  • Delivery and installation of two truss segments
  • Delivery and deployment of two new solar arrays
  • Perform three spacewalks to connect truss segments, remove restraints on solar arrays, and prepare the station for the next assembly mission by STS-116

    Crew seat assignments

Mission background

NASA managers decided to move the STS-115 launch date forward to August 27 to obtain better lighting conditions to photograph the external tank. This occurred before with STS-31 and STS-82. The launch window was co-ordinated with the Soyuz TMA-9 launch in mid-September, which delivered a new ISS crew and fresh supplies to the station. The Soyuz spacecraft operationally did not dock to the station while the Space Shuttle was there.
The mission marks:
  • 147th NASA crewed space flight.
  • 116th space shuttle flight since STS-1.
  • 27th flight of Atlantis.
  • 91st post-Challenger mission.
  • 3rd post-Columbia mission.
  • 1st post-Columbia mission of Atlantis.

    Mission timeline

Launch preparations

Atlantis was rolled out from the Orbiter Processing Facility to the Vehicle Assembly Building on July 24, 2006. It was lowered onto the mobile launcher platform on July 26 and rolled out to Pad 39B in the early morning hours of August 2. The rollout was scheduled for July 31, but a storm in the vicinity of the Kennedy Space Center resulted in a delay of two days from fears of the orbiter being hit by lightning, which could cause immeasurable damage.
On the weekend of August 5 to 6, 2006, engineers completed a "flight readiness" check of the shuttle's main engines, which were deemed ready for launch. The crew arrived at the Kennedy Space Center August 7, 2006, for four days of launch rehearsals, including a practice countdown August 10.
Top NASA managers held a Flight Readiness Review meeting August 15–16, 2006 to finalize the launch date. Foam loss from the external tank was a key issue at this meeting because on August 13, 2006, NASA announced there was an average amount of loss from the external tank of STS-121, the previous mission. Columbia's demise was due to a piece of foam, shed from its external tank, striking the shuttle's left wing during launch and causing a hole that was breached during re-entry.
The meeting also discussed problems with the bolts securing the shuttle's Ku-band antenna, which might not have been threaded correctly. The installation had been in place for several flights and hadn't experienced any problems. At the end of the two-day meeting, NASA managers had decided to proceed with the launch on August 27, 2006. However, on August 18, 2006, NASA decided to replace the antenna bolts with Atlantis still on the launch pad. NASA had no procedure to replace these on the pad, but the work was nonetheless completed by August 20, without affecting the planned launch date.
On August 25, 2006, a direct lightning strike, the most powerful recorded at Kennedy Space Center, hit the lightning rod atop the launch pad. As a result, on August 26 the Mission Management Team ordered the mission postponed for at least 24 hours to assess damage. On August 27, the decision was made to postpone the launch for another 24 hours, making the earliest possible launch date August 29, 2006, still unassured that there was no damage from the lightning strike and taking into account the possible threat from Hurricane Ernesto.
On August 28, 2006, it was decided to postpone the launch and rollback Atlantis to the VAB after updated forecasts projected Hurricane Ernesto would regain its strength and pass closer to Kennedy Space Center than previously anticipated. NASA began rolling back the shuttle on August 29, 2006, in the late morning, but by early afternoon the decision was made to move Atlantis back to the launch pad to weather out Tropical Storm Ernesto instead. The change came after weather forecasters determined that the storm wouldn't hit Kennedy Space Center as forcefully as they once thought. Its peak winds were expected to be less than 79 mph, NASA's limit for keeping the shuttle outdoors.
By the early morning of August 31, 2006, the storm had passed and inspection teams began a survey for damage to the launch facilities. Only three problems were discovered, all of which were simple repairs. A target date for launch was set for September 6 with the option to launch for another two days after NASA and Russian space managers agreed to extend the launch window by one day.
On the morning of September 3, 2006, the official countdown began at the T minus 43-hour mark, with about 30 hours of scheduled holds. In the early morning of September 6, 2006, engineers observed an apparent internal short when one of the three electricity producing fuel cells was powered up. When engineers couldn't figure out the problem in time, the launch was scrubbed for the day to further analyze the fuel cell problem. Late Wednesday evening NASA managers decided that they would not attempt a launch on Thursday, and scheduled the next launch attempt for September 8, 2006. Originally they had ruled out September 9 as a potential launch date due to a conflict with the planned Russian Soyuz mission Soyuz TMA-9, which was scheduled to, and did, launch on September 18, 2006. This caused some news agencies to report that Friday as the last chance for a launch until October.

September 8 (Launch attempt 1)

On the morning of September 8, 2006, it was reported that one of the engine cut-off sensors in the external tank had failed. About half an hour before the scheduled launch time, NASA announced it had decided to delay the launch for another 24 hours while the fuel was drained out of the external tank and the problem assessed. The sensor in question, ECO sensor No. 3, was proved to be faulty when it indicated that there was still liquid hydrogen in the external tank despite all of it being drained out. The other three ECO sensors correctly indicated a dry tank; and as long as they didn't start to malfunction, NASA could allow a launch with three out of the four ECO sensors operational.

September 9 (Flight day 1, Launch)

On September 9, 2006, all the engine cut-off sensors were working properly, and following a flawless countdown, at 15:15 UTC, Atlantis lifted off the launch pad to the International Space Station. As Atlantis launched, the International Space Station was above the northern Atlantic Ocean, between Greenland and Iceland.
During the climb to orbit, Mission Control asked the crew to reconfigure a cooling system that apparently had ice build up. The reconfiguration cleared the system, called the Flash Evaporator System, and it operated normally. Temporary ice in that cooling unit is not uncommon and has occurred on previous missions.
Moments after main engine cutoff, 8.5 minutes after liftoff, Tanner and MacLean used hand-held video and digital still cameras to document the external tank after it separated from the shuttle. That imagery, as well as imagery gathered by cameras in the shuttle's umbilical well where the tank was connected, was transmitted to the ground for review.

September 10 (Flight day 2)

File:STS-115 - Atlantis approaching ISS.jpg|thumb|Atlantis approaching the ISS with the P3/P4 truss segment and solar arrays in the payload bay.
During their first full day in space, the crew thoroughly examined Atlantis with the Orbiter Boom Sensor System, the 15 meter long extension for the shuttle's robotic arm. Pilot Chris Ferguson and mission specialists Dan Burbank and Steve MacLean performed a slow, steady inspection of the reinforced carbon-carbon panels along the leading edge of Atlantis starboard and port wings and the nose cap.
The crew worked ahead of schedule for most of the day readying the ship for docking and preparing for the mission's three planned extra-vehicular activities. Mission specialists Joe Tanner and Heide Stefanyshyn-Piper checked out the spacesuits and tools that they, Burbank and MacLean used during spacewalks set for Days 4, 5, and 7. The spacewalks installed the girder-like P3/P4 truss, deploy new solar arrays, and prepare them for operation.
On the space station, Expedition 13 Flight Engineer Jeffrey Williams prepared the orbiting laboratory for Atlantis arrival on Day 3. He readied the digital cameras that was used to take high-resolution photos of the shuttle's heat shield. With help from Commander Pavel Vinogradov, Williams pressurized the Pressurized Mating Adapter 2 at the end of the Destiny Laboratory Module, where Atlantis later docked. Vinogradov also prepacked equipment to be returned.