Space Shuttle Endeavour
Space Shuttle Endeavour was the fifth and final operational orbiter in NASA's Space Shuttle program, built as a replacement for the Challenger orbiter following its loss in the 1986 disaster.[1] Named after the HMS Endeavour, the ship commanded by Captain James Cook during his exploration of the South Pacific, the orbiter's name was selected through a nationwide elementary and secondary school essay contest in 1989. Delivered to NASA in May 1991 after construction by Rockwell International, Endeavour conducted its maiden flight, STS-49, on May 7, 1992, marking the first U.S. space mission to feature four spacewalks.[2] Over its 19-year career, Endeavour completed 25 missions, logging 299 days in space, orbiting Earth 4,677 times, and traveling approximately 122,883,151 miles.[3] Among its notable achievements, Endeavour played a pivotal role in the Hubble Space Telescope's first servicing mission (STS-61) in December 1993, where astronauts performed a record five spacewalks to install corrective optics and replace components, restoring the telescope's vision.[4] It also contributed significantly to the International Space Station (ISS) assembly, connecting the first two modules of the ISS—the U.S.-built Unity connecting module to the Russian-built Zarya module—during STS-88 in December 1998 and installing critical elements like the Alpha Magnetic Spectrometer on its final flight, STS-134, in May 2011.[2] Additionally, STS-67 aboard Endeavour set a then-record for shuttle mission duration at nearly 17 days, advancing astrophysics research with the Astro-2 observatory.[2] Following the conclusion of the Space Shuttle program in 2011, Endeavour was decommissioned and ferried to the California Science Center in Los Angeles in October 2012, where it is being prepared for permanent display in a vertical stack configuration simulating launch preparations as part of the forthcoming Samuel Oschin Air and Space Center exhibit (under construction as of 2025).[5] As the youngest of the shuttle fleet, Endeavour embodied advancements in orbiter design, including lighter composite materials and improved avionics, while supporting a wide array of scientific, technological, and international cooperative objectives that defined NASA's human spaceflight era.[6]Background and Construction
Development and Naming
The destruction of the Space Shuttle Challenger on January 28, 1986, during mission STS-51-L, which resulted in the loss of all seven crew members, grounded the shuttle fleet and prompted NASA to seek a replacement orbiter to maintain program viability.[7] This tragedy highlighted vulnerabilities in the shuttle design and operations, leading to extensive reviews and the decision to utilize existing structural spares to expedite a new build.[8] In August 1987, the United States Congress authorized the construction of orbiter vehicle OV-105 as a direct replacement for Challenger, with NASA awarding the contract to Rockwell International on July 31, 1987.[1] The project leveraged spare parts originally produced for Discovery and Atlantis, including the fuselage, wings, and payload bay components, which had been stored since the early 1980s, thereby reducing both time and expense. Construction began immediately at Rockwell's facility in Palmdale, California, focusing on integrating these spares with updated avionics and thermal protection systems. The naming process for OV-105 involved a nationwide contest among elementary and secondary school students, who were invited to propose names inspired by exploratory or research vessels.[1] In May 1989, President George H. W. Bush announced the winning entry: Endeavour, honoring the HMS Endeavour, the bark commanded by Captain James Cook during his 1768–1771 voyage to chart the Pacific Ocean and observe the transit of Venus.[9] This etymology reflects themes of perseverance and discovery, as "endeavour" signifies determined effort, aligning with the shuttle program's exploratory mission; the British spelling was retained to pay tribute to Cook's vessel, which advanced scientific mapping and navigation in uncharted territories.[10] Assembly progressed steadily, with final integration completed in July 1990, followed by systems testing.[11] On April 25, 1991, Endeavour rolled out from the Palmdale facility, marking a key milestone in its preparation for flight.[12] It was then ferried atop a modified Boeing 747 Shuttle Carrier Aircraft to NASA's Kennedy Space Center, arriving on May 7, 1991, where it underwent further processing, including mating to the external tank and solid rocket boosters.[1] During this delivery, Endeavour completed its first free-flight tests, including an unpowered approach and landing at Edwards Air Force Base on May 16, 1991, simulating orbital reentry conditions to validate its landing gear and aerodynamics.[13] The total construction cost for Endeavour amounted to approximately $1.7 billion, the lowest for any operational shuttle orbiter due to the reuse of spares and streamlined production.[8]Design Specifications and Assembly
Space Shuttle Endeavour, designated OV-105, measured 122 feet in length, had a wingspan of 78 feet, and stood 57 feet tall when positioned on the runway.[1] Its empty weight was approximately 178,000 pounds, with a payload capacity of up to 55,000 pounds to low Earth orbit.[14][15] The orbiter featured three RS-25 main engines mounted in its aft fuselage, which drew propellants from the external tank during launch.[16] It integrated with twin solid rocket boosters for initial ascent thrust and the aluminum-lithium external tank to supply liquid hydrogen and oxygen.[17] For thermal protection during reentry, Endeavour was covered by over 24,000 silica-based heat shield tiles, with reinforced carbon-carbon panels applied to the nose cap and leading edges of the wings to withstand temperatures exceeding 3,000 degrees Fahrenheit.[17] Construction of Endeavour began in 1987 at Rockwell International's facility in Palmdale, California, utilizing structural spare parts originally fabricated for Discovery and Atlantis as part of a 1983 NASA contract.[12][18] Final assembly was completed in July 1990, followed by rigorous vibration, acoustic, and systems testing through 1991 to verify structural integrity and operational readiness.[12] The orbiter was rolled out for public display in April 1991 before mating with its external tank and boosters at Kennedy Space Center.[12] As the fifth operational orbiter, Endeavour incorporated unique design enhancements from the outset, including advanced wiring harnesses and upgraded electrical systems to facilitate future technological integrations.[19] It also featured improved avionics with enhanced general-purpose computers, inertial measurement units, and a modernized flight deck layout for better crew interface and navigation precision.[19] These modifications, along with updated steering mechanisms and plumbing, distinguished Endeavour from earlier shuttles like Columbia and Challenger.[19]Operational History
Maiden Flight and Early Missions
Space Shuttle Endeavour's maiden flight, designated STS-49, launched on May 7, 1992, from Launch Complex 39B at Kennedy Space Center, marking the orbiter's integration into NASA's operational fleet as the fifth shuttle vehicle.[20] The seven-member crew, commanded by Daniel C. Brandenstein with pilot Kevin P. Chilton and mission specialists Pierre J. Thuot, Kathryn C. Thornton, Richard J. Hieb, Bruce E. Melnick, and Thomas D. Akers, focused primarily on retrieving the Intelsat VI communications satellite, which had been stranded in a low, unusable orbit since its failed deployment in March 1992.[20] The mission achieved this through a series of unprecedented spacewalks, including the first three-person extravehicular activity (EVA) in space history, where the crew successfully attached a new perigee kick motor to the satellite and boosted it to geosynchronous orbit.[21] Originally planned for seven days, the flight extended to eight days, 21 hours, 23 minutes, and 38 seconds, culminating in a landing at Edwards Air Force Base on May 16, 1992—the first shuttle touchdown using a drag chute to shorten the rollout distance.[20] Following its debut, Endeavour quickly transitioned to a series of diverse early missions that demonstrated its versatility in scientific research and satellite operations. On STS-47, launched September 12, 1992, the orbiter carried the Spacelab-J module for a joint NASA-NASDA (Japan) life sciences mission, conducting over 40 experiments in materials science, biotechnology, and human physiology.[22] This eight-day flight, lasting 7 days, 22 hours, 30 minutes, and 22 seconds, featured the first African American woman in space, mission specialist Mae Jemison, and landed at Kennedy Space Center on September 20, 1992.[22] Endeavour's next outing, STS-54, lifted off January 13, 1993, to deploy the Tracking and Data Relay Satellite-F (TDRS-F), enhancing NASA's communication network, while also supporting secondary payloads like the Diffuse X-ray Spectrometer and commercial bioprocessing experiments.[23] The five-day mission included an untethered EVA by mission specialists Carl J. Meade and Mario Runco Jr. to test procedures for future space station assembly, ending with a landing at Kennedy on January 19, 1993, after 5 days, 23 hours, 38 minutes, and 17 seconds.[23] Endeavour's early operational phase continued with STS-57 on June 21, 1993, which introduced the SPACEHAB module for the first time on the orbiter, hosting 22 middeck experiments in biotechnology, polymers, and crystal growth, alongside the retrieval of the European Retrievable Carrier (EURECA) satellite after 11 months in orbit.[24] The crew, including pilot Brian J. Duffy and mission specialists G. David Low, Nancy J. Currie, Janice E. Voss, and Peter J. K. Wisoff, performed the shuttle program's first EVA by a female astronaut (Voss) and Wisoff to prepare EURECA for reentry.[24] This 9-day, 23-hour, 44-minute mission landed at Kennedy Space Center on June 29, 1993, advancing commercial space utilization.[24] Throughout these initial flights, Endeavour encountered typical shuttle program challenges, including weather-related launch delays—such as the 34-minute postponement for STS-49 due to conditions at transatlantic abort sites—and minor thermal protection system tile damage from ascent debris, which required post-flight inspections but did not compromise mission safety or reusability.[20] These early operations established Endeavour's reliability, with the orbiter completing four missions in its first 13 months of service at a rate of approximately four to five flights per year, contributing to the fleet's sustained tempo of scientific and operational objectives.[21]Major Achievements and Upgrades
Endeavour's mid-career missions marked significant advancements in astronomical observation, Earth science, and materials research. During STS-61 in December 1993, the crew conducted the first servicing mission to the Hubble Space Telescope, performing five spacewalks to install the Corrective Optics Space Telescope Axial Replacement (COSTAR) instrument, which corrected the telescope's flawed primary mirror and restored its scientific capabilities.[4] This effort extended Hubble's operational life and enabled groundbreaking discoveries in cosmology and astrophysics. In April 1994, STS-59 deployed the Space Radar Laboratory-1 (SRL-1), a suite of imaging radars that mapped over 25 million square miles of Earth's surface, providing data on geology, ecology, and ocean dynamics to support environmental monitoring and disaster assessment.[25] The mission's synthetic aperture radar imagery offered unprecedented insights into surface deformation and vegetation structure, influencing subsequent global mapping projects. Further contributions included microgravity experiments on STS-69 in September 1995, where the Wake Shield Facility-2 was deployed to create a pristine vacuum environment for growing thin-film semiconductors, advancing semiconductor manufacturing techniques for space and terrestrial applications.[26] Endeavour also facilitated international collaboration, such as on STS-72 in January 1996, which featured Japanese astronaut Koichi Wakata and retrieved the Space Flyer Unit satellite, fostering U.S.-Japan partnerships in space retrieval and scientific payload operations.[27] A pinnacle achievement came with STS-88 in December 1998, when the crew delivered and connected the Unity module to the Russian Zarya module, initiating the structural assembly of the International Space Station (ISS) and enabling future habitation and research modules.[28] Throughout its service, Endeavour underwent key hardware upgrades to enhance performance and safety. In 1994, during a scheduled maintenance period, it integrated early avionics improvements, paving the way for later installations like the Multifunction Electronic Display System (MEDS) during its 2003-2005 Orbiter Maintenance Down Period (OMDP), which replaced analog gauges with digital flat-panel displays for improved situational awareness and reduced crew workload.[1] Advanced Auxiliary Power Units (APUs), upgraded from initial designs with enhanced turbine components, provided more reliable hydraulic power for maneuvering, contributing to smoother operations across missions.[1] Post-2003 Columbia accident investigations prompted extensive safety enhancements on Endeavour during its OMDP, including the addition of the Orbiter Boom Sensor System (OBSS) for in-orbit inspection of thermal protection tiles and reinforced wing leading edges with impact-resistant carbon-carbon panels.[29] These modifications, along with upgraded onboard video cameras for external tank debris monitoring, addressed foam shedding risks and ensured safer reentries, allowing Endeavour to resume ISS assembly flights without incident. By the end of 2000, Endeavour had accumulated over 170 days in space across 16 missions, underscoring its role in NASA's evolving human spaceflight program.[10]Final Missions and Retirement
As the International Space Station (ISS) neared completion in the late 2000s, Space Shuttle Endeavour shifted focus to delivering critical final components, beginning with STS-123 in March 2008. Launched on March 11, 2008, from Kennedy Space Center, the mission carried the Experiment Logistics Module-Pressurized Section (ELM-PS), the first segment of Japan's Kibo laboratory, and the Special Purpose Dexterous Manipulator (DEXTRE), a robotic arm system for maintenance tasks. The crew docked with the ISS on March 12, conducting three spacewalks to install the payloads and support station assembly, with the shuttle landing at Kennedy Space Center on March 26 after a duration of 15 days, 18 hours, and 17 minutes. This flight marked Endeavour's 20th mission and advanced the ISS's scientific capabilities by enabling pressurized experiment handling in Kibo. Subsequent missions continued this ISS-centric role. On STS-126, launched November 14, 2008, Endeavour delivered the Leonardo Multi-Purpose Logistics Module, repackaged as a permanent storage unit, along with crew quarters, exercise equipment, and life support upgrades to accommodate six-person expeditions aboard the station.[30] The 15-day, 20-hour mission included four spacewalks for hardware installation and ended with landing at Edwards Air Force Base on November 30 due to weather concerns at Kennedy.[30] STS-127 followed in July 2009, launching on July 15 to install the Kibo Japanese Experiment Module-Exposed Facility (JEM-EF), an external platform for unpressurized experiments, and the Exposed Logistics Module-Exposed Section (ELM-ES).[31] Delayed by technical issues, the mission spanned 15 days, 16 hours, with five spacewalks, and landed at Kennedy on August 1, completing Kibo's core structure.[31] Endeavour's penultimate flight, STS-130, launched February 8, 2010, and delivered Node 3 (Tranquility), the final pressurized module, and the Cupola, a seven-window observatory for crew operations and Earth observation.[32] The 13-day, 18-hour mission featured three spacewalks to connect the components, enhancing the ISS's living volume and control capabilities, before landing at Kennedy on February 21.[32] The orbiter's final mission, STS-134, originally planned for 2010 but delayed by payload readiness, launched May 16, 2011, carrying the Alpha Magnetic Spectrometer-02 (AMS-02), a cosmic ray detector designed to search for antimatter and dark matter.[33] Over 15 days, 16 hours, the crew performed four spacewalks to install AMS-02 on the ISS and transfer spare parts, landing at Edwards Air Force Base on June 1, 2011.[33] The Space Shuttle program's retirement in 2011 stemmed from President George W. Bush's 2004 Vision for Space Exploration, which prioritized completing ISS assembly before transitioning to new exploration vehicles, amid escalating costs exceeding $200 billion over three decades and safety risks highlighted by the 2003 Columbia disaster.[34] Budget constraints limited NASA funding, rendering the aging fleet unsustainable for long-term operations.[1] Endeavour, the youngest orbiter built as Challenger's replacement, was selected from over 20 proposals for display at the California Science Center in Los Angeles due to its strong educational outreach plan. Across 25 missions, Endeavour accumulated 299 days in space, completing 4,671 orbits and traveling 122,883,151 miles, concluding an era of reusable spacecraft operations.[33]Missions
Mission Summary Table
| Mission # | Designation | Launch Date | Launch Pad | Landing Date | Landing Site | Duration | Crew Size | Primary Objectives/Notes |
|---|---|---|---|---|---|---|---|---|
| 1 | STS-49 | May 7, 1992 | 39B | May 16, 1992 | Edwards AFB | 8 days, 21 hours, 0 minutes | 7 | Rescue, repair, and redeploy Intelsat VI (F-3) satellite; first 3 EVAs in a single mission.[20] |
| 2 | STS-47 | September 12, 1992 | 39A | September 20, 1992 | KSC | 7 days, 22 hours, 30 minutes | 7 | Spacelab J mission; life science and materials processing experiments; first African-American woman in space (Mae Jemison). |
| 3 | STS-54 | January 13, 1993 | 39B | January 22, 1993 | KSC | 5 days, 23 hours, 15 minutes | 5 | Deploy TDRS-6; conduct IMAX filming and life sciences experiments. |
| 4 | STS-57 | June 21, 1993 | 39B | July 1, 1993 | KSC | 9 days, 23 hours, 57 minutes | 6 | SPACEHAB-01 middeck experiments; retrieve EURECA satellite; first commercial middeck payload. |
| 5 | STS-61 | December 2, 1993 | 39B | December 13, 1993 | KSC | 10 days, 19 hours, 21 minutes | 7 | First Hubble Space Telescope servicing mission; 5 EVAs to install corrective optics and instruments. |
| 6 | STS-59 | April 9, 1994 | 39A | April 20, 1994 | KSC | 11 days, 5 hours, 15 minutes | 6 | Space Radar Laboratory-1 (SRL-1); SIR-C/X-SAR and shuttle imaging radar mapping Earth. |
| 7 | STS-68 | September 30, 1994 | 39A | October 11, 1994 | Edwards AFB | 11 days, 5 hours, 20 minutes | 6 | Space Radar Laboratory-2 (SRL-2); Earth observation with SIR-C/X-SAR. |
| 8 | STS-67 | March 2, 1995 | 39A | March 18, 1995 | Edwards AFB | 16 days, 15 hours, 9 minutes | 7 | Astro-2 ultraviolet astronomy mission; longest Endeavour flight at the time. |
| 9 | STS-69 | September 7, 1995 | 39A | September 18, 1995 | KSC | 10 days, 20 hours, 56 minutes | 5 | Deploy Spartan-207/Reflight and Wake Shield Facility; rendezvous radar test. |
| 10 | STS-72 | January 11, 1996 | 39B | January 20, 1996 | KSC | 8 days, 22 hours, 2 minutes | 6 | Retrieve SFU satellite and OAST-Flyer; spacewalk test. |
| 11 | STS-77 | May 19, 1996 | 39B | May 29, 1996 | KSC | 10 days, 0 hours, 37 minutes | 6 | Spacelab Inflatable Antenna Experiment; deploy/sub-retrieve Spartan-207. |
| 12 | STS-89 | January 22, 1998 | 39A | February 2, 1998 | SLF, KSC | 8 days, 19 hours, 47 minutes | 7 | Pegasus 3 satellite deploy; Mir-21 crew exchange (Andrew Thomas). |
| 13 | STS-88 | December 4, 1998 | 39A | December 17, 1998 | KSC | 11 days, 19 hours, 18 minutes | 6 | First ISS assembly mission; connect Unity module to Zarya.[28] |
| 14 | STS-99 | February 11, 2000 | 39A | February 22, 2000 | KSC | 11 days, 5 hours, 42 minutes | 6 | SRTM radar mapping of Earth's surface; highest altitude shuttle mission. |
| 15 | STS-97 | December 5, 2000 | 39B | December 15, 2000 | KSC | 10 days, 3 hours, 10 minutes | 5 | ISS 5A.1; install first set of U.S. solar arrays and radiators. |
| 16 | STS-100 | April 8, 2001 | 39A | April 21, 2001 | Edwards AFB | 11 days, 12 hours, 54 minutes | 7 | ISS 6A; deliver Canadarm2 robotic arm. |
| 17 | STS-108 | December 5, 2001 | 39A | December 17, 2001 | KSC | 11 days, 19 hours, 35 minutes | 7 | ISS UF-2; crew rotation (Expedition 3 to 4); deliver Destiny lab logistics.[35] |
| 18 | STS-111 | June 5, 2002 | 39A | June 19, 2002 | Edwards AFB | 13 days, 20 hours, 55 minutes | 7 | ISS UF-5; deliver MPLM Raffaello; crew rotation (Expedition 4 to 5). |
| 19 | STS-113 | November 23, 2002 | 39A | December 7, 2002 | KSC | 13 days, 18 hours, 48 minutes | 7 | ISS 11A; deliver P5 truss segment; crew rotation (Expedition 5 to 6). |
| 20 | STS-118 | August 8, 2007 | 39A | August 21, 2007 | KSC | 12 days, 17 hours, 55 minutes | 7 | ISS 13A.1; deliver S5 truss segment; 4 EVAs; teacher astronaut Barbara Morgan.[36] |
| 21 | STS-123 | March 11, 2008 | 39A | March 26, 2008 | KSC | 15 days, 18 hours, 19 minutes | 7 | ISS 1J/A; deliver Kibo lab and Dextre robot; 4 EVAs.[37] |
| 22 | STS-126 | November 14, 2008 | 39A | December 1, 2008 | Edwards AFB | 15 days, 20 hours, 30 minutes | 7 | ISS ULF-2; deliver Leonardo MPLM and crew; 4 EVAs for repairs. |
| 23 | STS-127 | July 15, 2009 | 39A | August 1, 2009 | KSC | 15 days, 16 hours, 45 minutes | 7 | ISS 2J/A; install Kibo exposed facility and pallet; 5 EVAs.[31] |
| 24 | STS-130 | February 8, 2010 | 39A | February 21, 2010 | KSC | 13 days, 18 hours, 43 minutes | 6 | ISS 20A; install Node 3 Tranquility and Cupola; 3 EVAs.[32] |
| 25 | STS-134 | May 16, 2011 | 39A | June 1, 2011 | Edwards AFB | 15 days, 17 hours, 1 minute | 6 | ISS ULF6; deliver Alpha Magnetic Spectrometer (AMS) and ELC-3; 4 EVAs; final Endeavour mission.[33] |