2011 American crewed spaceflight to the ISS and final flight of Space Shuttle Endeavour
STS-134 (ISS assembly flight ULF6) was the penultimate mission of NASA's Space Shuttle program and the 25th and last spaceflight of Space Shuttle "Endeavour". This flight delivered the Alpha Magnetic Spectrometer and an ExPRESS Logistics Carrier to the International Space Station. Mark Kelly served as the mission commander. STS-134 was expected to be the final Space Shuttle mission if STS-135 did not receive funding from Congress. However, in February 2011, NASA stated that STS-135 would fly "regardless" of the funding situation. STS-135, flown by "Atlantis", took advantage of the processing for STS-335, the Launch on Need mission that would have been necessary if the STS-134 crew became stranded in orbit.
Changes in the design of the main payload, AMS-02, as well as delays to STS-133, led to delays in the mission. The first launch attempt on April 29, 2011, was scrubbed at 12:20 pm by launch managers due to problems with two heaters on one of the orbiter's auxiliary power units (APU). "Endeavour" launched successfully at 08:56:28 EDT (12:56:28 UTC) on May 16, 2011, and landed for the final time on June 1, 2011.
Crew.
NASA announced the STS-134 crew on August 10, 2009.
Background.
The Space Shuttle had been scheduled to be retired from service after STS-133, but controversy over the cancellation of several International Space Station components, most notably the Alpha Magnetic Spectrometer, in order to meet deadlines for the retirement of the shuttle, caused the United States Government to consider ordering an additional mission. On June 19, 2008, the United States House of Representatives passed the NASA Authorization Act of 2008, giving NASA funding for one additional mission to "deliver science experiments to the station".
The same mandate was included in the U.S. Senate version of the NASA Authorization Act that was unanimously approved by the Senate Committee on Commerce, Science, and Transportation on June 25, 2008. It was amended and passed by the full Senate on September 25, 2008, passed by the House on September 27, 2008, and signed by President George W. Bush on October 15, 2008. Bush had previously opposed any additional shuttle missions, as they could delay the transition to Project Constellation. In the spring of 2009, the Obama Administration included funds for the STS-134 mission in its proposed 2010 NASA budget.
STS-134 was planned to be the final regularly scheduled mission of the NASA Space Shuttle Program, but with the passing in 2011 of an appropriations bill authorizing the conversion of STS-335 to STS-135, this was no longer the case. It was also originally scheduled to coincide with Expedition 26 before delays in the Space Shuttle launch schedule pushed it past that Expedition. If STS-134 had launched during Expedition 26, then Mark Kelly and Expedition 26 commander Scott Kelly would have become the first siblings (and twins) to fly in space at the same time.
Shuttle Commander Mark Kelly's wife, U.S. Representative Gabby Giffords, flew to the Kennedy Space Center (KSC) in Florida to view the first launch attempt, her first trip since moving from Tucson to Houston for rehabilitation after being seriously wounded in the January 2011 Tucson shooting. On May 16, Giffords was again at KSC for the launch, which was "one of the most anticipated in years," according to "The New York Times".
U.S. President Barack Obama scheduled a visit to Kennedy Space Center on April 29, 2011, to view the launch, and despite the canceled launch attempt he toured an Orbiter Processing Facility at Launch Complex 39 and met with Giffords and the six crewmembers.
Mission payload.
Alpha Magnetic Spectrometer 2.
The Alpha Magnetic Spectrometer 2 (AMS-02) was carried to the ISS in "Endeavour"'s payload bay, and was attached to the ISS's S3 truss segment. The AMS-02 unit is a particle physics detector which contains a large permanent magnet, and is designed to search for antimatter and investigate the origin and structure of dark matter.
According to the original design plan, a cryogenic, superconducting magnet system was developed for the AMS-02. This was reported by NASA to be a critical technology, granting the instrument the high sensitivity needed to achieve mission objectives. Late in its development, however, poorly understood anomalous heating in the cryogenic magnet system was discovered. As a result, the AMS-02 experiment leader, Samuel C. C. Ting, decided to replace the superconducting magnet inside the spectrometer with the permanent magnet previously used in AMS-01.
ExPRESS Logistics Carrier 3.
The ExPRESS Logistics Carrier 3 (ELC3) carried several Orbital Replacement Units (ORU) that were too large or too heavy for other spacecraft to carry to the ISS. These ORUs included a High Pressure Gas Tank (HPGT), an Ammonia Tank Assembly (ATA), the S band Antenna Sub-System Assembly #2 &amp; 3 (SASA), a Special Purpose Dextrous Manipulator (SPDM) Arm with Orbital Replacement Unit change-out mechanism, a Space Test Program Houston 3 Department of Defense payload, and a spare ELC pallet controller avionics box.
Materials on International Space Station Experiment.
The STS-134 mission delivered the Materials on International Space Station Experiment 8 (MISSE) experiments, and returned the completed MISSE 7 experiments to Earth. MISSE 7 had been delivered to the ISS on STS-129 in 2009.
Sensor Test of Orion Rel-nav Risk Mitigation Detailed Test Objective kit.
The Orion Rel-nav Sensor was mounted on the Orbiter Docking System (ODS) in Trajectory Control Sensor slot 1 and on an Adaptive Payload Carrier in the bay 3 port of the Payload Bay. For the STORRM Detailed Test Objective (DTO), after "Endeavour" undocked, it completed its normal fly-around of the station. The crew then guided "Endeavour" back towards the station, flying a nominal orbiter trajectory for docking to the ISS's Pressurized Mating Adapter-2. However, the shuttle did not actually dock with the ISS again; instead, it was positioned below the station.
On STS-131, the docking target on the ISS was enhanced with reflectors, to allow for the characterization of the Orion Rel-Nav sensors' performance during STS-134's rendezvous and proximity operations with the ISS. These proximity operations were tested during approach and docking, undocking, flyaround (time permitting), and during a modified separation from the ISS. During the modified separation, the crew performed a series of re-rendezvous burns that put the orbiter on an Orion-like rendezvous profile. Afterwards, instead of re-docking to the ISS, the crew performed a full separation.
GLACIER Freezer Module.
STS-134 carried a new Glacier module to the ISS and returned two old ones to Earth. The Glacier units were used to store and return science samples on the Space Shuttle.
Orbiter Boom Sensor System.
STS-134 left its Orbiter Boom Sensor System (OBSS) permanently on the ISS for use in reaching places that the Canadarm2 cannot get to on its own. The usefulness of having an OBSS available for use at the station was demonstrated during Scott Parazynski's repair of the torn P6 solar panel on STS-120. The feasibility of leaving an OBSS attached to ISS for a long period of time was demonstrated when the STS-123 mission left one behind for use during the subsequent STS-124 mission.
Lego kits.
"Endeavour" brought 13 Lego kits to the ISS, where astronauts built Lego models to see how they would react in microgravity, as part of the "Lego Bricks in Space" program. The results were shared with schools as part of an educational project.
Shuttle LIFE.
The LIFE precursor mission was launched aboard "Endeavour". This Planetary Society project was to test the mission destined for Fobos-Grunt. The stage rehearsal was deemed fully successful.
STEM Bars.
"Endeavour" brought specialized nutrition bars, called "STEM Bars", to the ISS. These were created by high school students and sisters Mikayla and Shannon Diesch. The nutrition bars were certified for spaceflight by meeting a specific NASA-developed nutritional profile, and had to pass strict microbial testing. The STEM Bars were flown to support the work of the Battle Creek, Michigan-based sisters to raise awareness of the importance of STEM education among their peers, an outreach effort which they started after they won the 2010 Conrad Foundation Spirit of Innovation Awards.
The Little Mole.
A figurine of the Little Mole was successfully brought back to Earth by Andrew Feustel. It was later presented to the character's creator, Zdeněk Miler, and used for space science popularization mainly in the Czech Republic.
Mission experiments.
"Endeavour" performed four Department of Defense payloads of opportunity: MAUI, SEITI, RAMBO-2, and SIMPLEX. All four of these experiments required engine and thruster firings, and were to be completed only if there was sufficient propellant on board "Endeavour". 
Mission milestones.
The mission marked:
Shuttle processing.
Rollout.
Rollout of "Endeavour" commenced on March 10, 2011, at 19:56 EST and terminated on March 11, 2011, at 03:49 EST.
Launchpad fatality.
At around 07:40 EDT on March 14, 2011, United Space Alliance engineer James Vanover committed suicide by jumping from the STS-134 launchpad. "Endeavour" was at the pad when the incident occurred. As a result, work on the Space Shuttle was suspended for the day while grief counseling was offered to the workforce. NASA officials believed this to be the first launchpad fatality since 1981.
Mission timeline.
May 16 (Flight Day 1 – Launch).
"Endeavour" lifted off from Kennedy Space Center's Launch Complex 39 at 08:56 EDT on May 16, 2011. The launch of "Endeavour" came after an on-time tanking process which filled the shuttle's external tank with more than of liquid oxygen and liquid hydrogen; the tanking started at 23:36 EDT on May 15, 2011. Once the shuttle and crew were on-orbit, they set about preparing the shuttle for the mission ahead. The first tasks they completed were opening the payload bay doors, activating the Ku-band antenna, and activating the Shuttle Remote Manipulator System (SRMS), also known as the Canadarm. Prior to this, commander Mark Kelly and pilot Greg Johnson completed an engine firing, known as the OMS-2 burn, to circularize the orbit of the shuttle. They also completed another engine firing, the NC-1 burn, to help the shuttle catch up to the International Space Station (ISS). After completing these initial tasks, the crew activated the Alpha Magnetic Spectrometer, allowing it to be monitored by teams on the ground. Later in the crew's work day, they downlinked video recordings that had been shot of the external tank by mission specialist Mike Fincke.
May 17 (Flight Day 2 – OBSS inspection).
On flight day 2, the crew of "Endeavour" completed several tasks in preparation for the docking on flight day 3. The first and most important of these tasks was surveying the shuttle's Thermal Protection System (TPS). The Orbiter Boom Sensor System (OBSS) was used to survey the wing leading edge and nose cone. The Shuttle Remote Manipulator System (SRMS, or Canadarm 1) was also used to look at the thermal tiles and blankets on and around the Orbital Maneuvering System (OMS) pods. After the survey was complete, the Express Logistics Carrier (ELC) 3 was grappled by the SRMS. While the survey was conducted by Greg Johnson and mission specialists Roberto Vittori and Greg Chamitoff, the rest of the crew prepared the orbiter for docking. This included installing tools such as a center-line camera in the Orbiter Docking System, along with various other sensors used to gauge distance and speed. Kelly and mission specialists Mike Fincke and Drew Feustel furthermore checked out the two spacesuits carried on "Endeavour", in preparation for the mission's four planned spacewalks.
May 18 (Flight Day 3 – ISS rendezvous and ELC installation).
Flight day 3 saw the docking of "Endeavour" to the Pressurized Mating Adapter (PMA) 2 on the ISS. The docking occurred on May 18, 2011, at 10:14 UTC. After the shuttle docked, the six astronauts of STS-134 joined the Expedition 27 crew on board the ISS. The joint crews completed a series of leak checks and opened the hatches at 11:38 UTC. Once the hatches were open, the joint crew held a welcome ceremony and completed a safety briefing. The first task for the joint crew was to unberth the Express Logistics Carrier (ELC) 3, and attach it to its final location on the ISS's Port 3 (P3) truss segment. Express Logistics Carrier 3 was removed from the payload bay of "Endeavour" by the SRMS and handed off to the Space Station Remote Manipulator System (SSRMS), also known as Canadarm2. The ELC 3 was finally installed at 16:18 UTC. Kelly began to transfer oxygen from space shuttle "Endeavour" to the ISS. Mike Fincke and Drew Feustel transferred the two Extravehicular Mobility Units (EMU) to the ISS's "Quest" Airlock in preparation for their use during the mission's four spacewalks.
May 19