Editing Space Shuttle (section)

==Description==
The Space Shuttle was the first operational orbital spacecraft designed for [[Reusable launch system|reuse]]. Each Space Shuttle orbiter was designed for a projected lifespan of 100 launches or ten years of operational life, although this was later extended.<ref name="sivolella">{{cite book |last= Sivolella |first= David |title= The Space Shuttle Program: Technologies and Accomplishments |publisher= [[Springer Praxis Books]] |date= 2017 |location= Hemel Hempstead |url= https://books.google.com/books?id=7nknDwAAQBAJ&pg=PP1 |doi= 10.1007/978-3-319-54946-0 |isbn= 978-3-319-54944-6 |access-date= October 17, 2020 |archive-date= April 17, 2021 |archive-url= https://web.archive.org/web/20210417052324/https://books.google.com/books?id=7nknDwAAQBAJ&pg=PP1 |url-status= live}}</ref>{{rp|11}} At launch, it consisted of the [[Space Shuttle orbiter|orbiter]], which contained the [[List of Space Shuttle crews|crew]] and payload, the [[Space Shuttle external tank|external tank]] (ET), and the two [[Space Shuttle Solid Rocket Booster|solid rocket boosters]] (SRBs).<ref name=jenkins>{{cite book |last=Jenkins |first=Dennis R. |title=Space Shuttle: The History of the National Space Transportation System |publisher=Voyageur Press |year=2001 |isbn=978-0-9633974-5-4}}</ref>{{rp|363}}

Responsibility for the Space Shuttle components was spread among multiple NASA field centers. The KSC was responsible for launch, landing, and turnaround operations for equatorial orbits (the only orbit profile actually used in the program). The U.S. Air Force at the [[Vandenberg Air Force Base]] was responsible for launch, landing, and turnaround operations for polar orbits (though this was never used). The [[Johnson Space Center]] (JSC) served as the central point for all Shuttle operations and the MSFC was responsible for the main engines, external tank, and solid rocket boosters. The [[John C. Stennis Space Center]] handled main engine testing, and the [[Goddard Space Flight Center]] managed the global tracking network.<ref>{{cite web |url=http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/centers.html |title=NASA Centers And Responsibilities |publisher=NASA |last=Dumoulin |first=Jim |date=August 31, 2000 |access-date=March 22, 2020 |archive-date=June 21, 2020 |archive-url=https://web.archive.org/web/20200621082408/https://science.ksc.nasa.gov/shuttle/technology/sts-newsref/centers.html |url-status=live }}</ref>

===Orbiter===
{{main|Space Shuttle orbiter}}
[[File:Shuttle profiles.jpg|center|thumb|upright=2.65|alt=The five Space Shuttle orbiters launching|Shuttle launch profiles. From left: ''[[Space Shuttle Columbia|Columbia]]'', ''[[Space Shuttle Challenger|Challenger]]'', ''[[Space Shuttle Discovery|Discovery]]'', ''[[Space Shuttle Atlantis|Atlantis]]'', and ''[[Space Shuttle Endeavour|Endeavour]]'']]

The orbiter had design elements and capabilities of both a rocket and an aircraft to allow it to launch vertically and then land as a glider.<ref name=jenkins />{{rp|365}} Its three-part fuselage provided support for the crew compartment, cargo bay, flight surfaces, and engines. The rear of the orbiter contained the Space Shuttle Main Engines (SSME), which provided thrust during launch, as well as the Orbital Maneuvering System (OMS), which allowed the orbiter to achieve, alter, and exit its orbit once in space. Its double-[[delta wing]]s were {{convert|60|ft|m|sigfig=2|sp=us|order=flip|adj=on|abbr=on}} long, and were swept 81° at the inner leading edge and 45° at the outer leading edge. Each wing had an inboard and outboard [[elevon]] to provide flight control during reentry, along with a flap located between the wings, below the engines to control [[Aircraft principal axes#Transverse axis (pitch)|pitch]]. The orbiter's [[vertical stabilizer]] was swept backwards at 45° and contained a [[Rudder#Aircraft rudders|rudder]] that could split to act as a [[Air brake (aeronautics)|speed brake]].<ref name=jenkins />{{rp|382–389}} The vertical stabilizer also contained a two-part [[drogue parachute|drag parachute]] system to slow the orbiter after landing. The orbiter used [[Landing gear#Retractable gear|retractable landing gear]] with a nose landing gear and two main landing gear, each containing two tires. The main landing gear contained two brake assemblies each, and the nose landing gear contained an electro-hydraulic steering mechanism.<ref name=jenkins />{{rp|408–411}}

====Crew====
The Space Shuttle crew varied per mission. They underwent rigorous testing and training to meet the [[Astronaut#NASA candidacy requirements|qualification requirements]] for their roles. The crew was divided into three categories: Pilots, Mission Specialists, and Payload Specialists. Pilots were further divided into two roles: the Space Shuttle Commander, who would seat in the forward left seat and the Space Shuttle Pilot who would seat in the forward right seat.<ref>{{Cite web |title=Space Shuttle Astronaut Qualifications {{!}} Spaceline |url=https://www.spaceline.org/united-states-manned-space-flight/us-astronaut-selection-drafts-and-qualifications/space-shuttle-astronaut-qualifications/ |access-date=April 1, 2023 |language=en-US |archive-date=March 24, 2023 |archive-url=https://web.archive.org/web/20230324065946/https://www.spaceline.org/united-states-manned-space-flight/us-astronaut-selection-drafts-and-qualifications/space-shuttle-astronaut-qualifications/ |url-status=live}}</ref> The test flights, STS-1 through STS-4 only had two members each, the commander and pilot. The commander and the pilot were both qualified to fly and land the orbiter. The on-orbit operations, such as experiments, payload deployment, and EVAs, were conducted primarily by the mission specialists who were specifically trained for their intended missions and systems. Early in the Space Shuttle program, NASA flew with payload specialists, who were typically systems specialists who worked for the company paying for the payload's deployment or operations. The final payload specialist, [[Gregory B. Jarvis]], flew on [[STS-51-L]], and future non-pilots were designated as mission specialists. An astronaut flew as a crewed spaceflight engineer on both [[STS-51-C]] and [[STS-51-J]] to serve as a military representative for a [[National Reconnaissance Office]] payload. A Space Shuttle crew typically had seven astronauts, with [[STS-61-A]] flying with eight.<ref name=jenkins2016 />{{rp|III-21}}

====Crew compartment====
The crew compartment comprised three decks and was the pressurized, habitable area on all Space Shuttle missions. The flight deck consisted of two seats for the commander and pilot, as well as an additional two to four seats for crew members. The mid-deck was located below the flight deck and was where the galley and crew bunks were set up, as well as three or four crew member seats. The mid-deck contained the airlock, which could support two astronauts on an [[extravehicular activity]] (EVA), as well as access to pressurized research modules. An equipment bay was below the mid-deck, which stored environmental control and waste management systems.<ref name= shuttle_manual />{{rp|60–62}}<ref name=jenkins />{{rp|365–369}}

On the first four Shuttle missions, astronauts wore modified U.S. Air Force high-altitude full-pressure suits, which included a full-pressure helmet during ascent and descent. From the fifth flight, [[STS-5]], until the loss of ''Challenger'', the crew wore one-piece light blue [[nomex]] flight suits and partial-pressure helmets. After the ''Challenger'' disaster, the crew members wore the Launch Entry Suit (LES), a partial-pressure version of the high-altitude pressure suits with a helmet. In 1994, the LES was replaced by the full-pressure [[Advanced Crew Escape Suit]] (ACES), which improved the safety of the astronauts in an emergency situation. ''Columbia'' originally had modified [[SR-71]] [[zero-zero ejection seat]]s installed for the [[Approach and Landing Tests|ALT]] and first four missions, but these were disabled after STS-4 and removed after [[STS-9]].<ref name=jenkins />{{rp|370–371}}

[[File:STSCPanel.jpg|thumb|right|alt=The view from the Atlantis cockpit while in orbit|''[[Space Shuttle Atlantis|Atlantis]]'' was the first Shuttle to fly with a [[glass cockpit]], on [[STS-101]].]]
The flight deck was the top level of the crew compartment and contained the flight controls for the orbiter. The commander sat in the front left seat, and the pilot sat in the front right seat, with two to four additional seats set up for additional crew members. The instrument panels contained over 2,100 displays and controls, and the commander and pilot were both equipped with a [[heads-up display]] (HUD) and a [[Joystick#Electronic joysticks|Rotational Hand Controller]] (RHC) to [[gimbal]] the engines during powered flight and fly the orbiter during unpowered flight. Both seats also had [[rudder]] controls, to allow rudder movement in flight and nose-wheel steering on the ground.<ref name=jenkins />{{rp|369–372}} The orbiter vehicles were originally installed with the Multifunction [[Cathode-ray tube|CRT]] Display System (MCDS) to display and control flight information. The MCDS displayed the flight information at the commander and pilot seats, as well as at the aft seating location, and also controlled the data on the HUD. In 1998, ''Atlantis'' was upgraded with the Multifunction Electronic Display System (MEDS), which was a [[glass cockpit]] upgrade to the flight instruments that replaced the eight MCDS display units with 11 multifunction colored digital screens. MEDS was flown for the first time in May 2000 on [[STS-101]], and the other orbiter vehicles were upgraded to it. The aft section of the flight deck contained windows looking into the payload bay, as well as an RHC to control the [[Remote Manipulator System]] during cargo operations. Additionally, the aft flight deck had monitors for a [[closed-circuit television]] to view the cargo bay.<ref name=jenkins />{{rp|372–376}}

The mid-deck contained the crew equipment storage, sleeping area, galley, medical equipment, and hygiene stations for the crew. The crew used modular lockers to store equipment that could be scaled depending on their needs, as well as permanently installed floor compartments. The mid-deck contained a port-side hatch that the crew used for entry and exit while on Earth.<ref name="jenkins2016"/>{{rp|II–26–33}}

==== Airlock ====
The [[airlock]] is a structure installed to allow movement between two spaces with different gas components, conditions, or pressures. Continuing on the mid-deck structure, each orbiter was originally installed with an internal airlock in the mid-deck. The internal airlock was installed as an external airlock in the payload bay on ''Discovery'', ''Atlantis'', and ''Endeavour'' to improve docking with [[Mir]] and the [[ISS]], along with the [[Orbiter Docking System]].<ref name="jenkins2016">{{cite book |last= Jenkins |first= Dennis R. |title= Space Shuttle: Developing an Icon – 1972–2013|isbn=978-1-58007-249-6 |publisher= Specialty Press |date= 2016}}</ref>{{rp|II–26–33}} The airlock module can be fitted in the mid-bay, or connected to it but in the payload bay.{{r|shuttle_manual|p=81}} With an internal cylindrical volume of {{convert|1.60|m|ftin|abbr=off}} diameter and {{convert|2.11|m|ftin|abbr=off}} in length, it can hold two suited astronauts. It has two D-shaped hatchways {{convert|1.02|m|in|abbr=on}} long (diameter), and {{convert|0.91|m|in|abbr=on}} wide.{{r|shuttle_manual|p=82}}

====Flight systems====
The orbiter was equipped with an [[avionics]] system to provide information and control during atmospheric flight. Its avionics suite contained three [[microwave scanning beam landing system]]s, three [[gyroscope]]s, three [[Tactical air navigation system|TACAN]]s, three [[accelerometer]]s, two [[radar altimeter]]s, two [[barometric altimeter]]s, three [[attitude indicator]]s, two [[Machmeter|Mach indicator]]s, and two [[Aviation transponder interrogation modes|Mode&nbsp;C]] [[Transponder (aeronautics)|transponders]]. During reentry, the crew deployed two [[Air data boom|air data probes]] once they were traveling slower than Mach 5. The orbiter had three [[Inertial measurement unit|inertial measuring units]] (IMU) that it used for guidance and navigation during all phases of flight. The orbiter contains two [[star tracker]]s to align the IMUs while in orbit. The star trackers are deployed while in orbit, and can automatically or manually align on a star. In 1991, NASA began upgrading the inertial measurement units with an [[inertial navigation system]] (INS), which provided more accurate location information. In 1993, NASA flew a [[GPS]] receiver for the first time aboard [[STS-51]]. In 1997, Honeywell began developing an integrated GPS/INS to replace the IMU, INS, and TACAN systems, which first flew on [[STS-118]] in August 2007.<ref name=jenkins />{{rp|402–403}}

While in orbit, the crew primarily communicated using one of four [[S band]] radios, which provided both voice and data communications. Two of the S&nbsp;band radios were [[phase modulation]] [[transceiver]]s, and could transmit and receive information. The other two S&nbsp;band radios were [[frequency modulation]] [[transmitter]]s and were used to transmit data to NASA. As S&nbsp;band radios can operate only within their [[Line-of-sight propagation|line of sight]], NASA used the [[Tracking and Data Relay Satellite System]] and the [[Spacecraft Tracking and Data Acquisition Network]] ground stations to communicate with the orbiter throughout its orbit. Additionally, the orbiter deployed a high-bandwidth [[Ku band|K<sub>u</sub>&nbsp;band]] radio out of the cargo bay, which could also be utilized as a rendezvous radar. The orbiter was also equipped with two [[UHF]] radios for communications with [[air traffic control]] and astronauts conducting EVA.<ref name=jenkins />{{rp|403–404}}

[[File:Space Shuttle General Purpose Computer.jpg|thumb|right|alt=The two computers used in the orbiter|AP-101S (left) and AP-101B general purpose computers]]
The Space Shuttle's [[fly-by-wire]] control system was entirely reliant on its main computer, the Data Processing System (DPS). The DPS controlled the flight controls and thrusters on the orbiter, as well as the ET and SRBs during launch. The DPS consisted of five general-purpose computers (GPC), two magnetic tape mass memory units (MMUs), and the associated sensors to monitor the Space Shuttle components.<ref name=jenkins />{{rp|232–233}} The original GPC used was the IBM [[IBM System/4 Pi#AP-101|AP-101B]], which used a separate [[central processing unit]] (CPU) and input/output processor (IOP), and [[non-volatile memory|non-volatile]] [[Solid-state drive|solid-state memory]]. From 1991 to 1993, the orbiter vehicles were upgraded to the AP-101S, which improved the memory and processing capabilities, and reduced the volume and weight of the computers by combining the CPU and IOP into a single unit. Four of the GPCs were loaded with the Primary Avionics Software System (PASS), which was Space Shuttle-specific software that provided control through all phases of flight. During ascent, maneuvering, reentry, and landing, the four PASS GPCs functioned identically to produce quadruple redundancy and would error check their results. In case of a software error that would cause erroneous reports from the four PASS GPCs, a fifth GPC ran the Backup Flight System, which used a different program and could control the Space Shuttle through ascent, orbit, and reentry, but could not support an entire mission. The five GPCs were separated in three separate bays within the mid-deck to provide redundancy in the event of a cooling fan failure. After achieving orbit, the crew would switch some of the GPCs functions from guidance, navigation, and control (GNC) to systems management (SM) and payload (PL) to support the operational mission.<ref name=jenkins />{{rp|405–408}} The Space Shuttle was not launched if its flight would run from December to January, as its flight software would have required the orbiter vehicle's computers to be reset at the year change. In 2007, NASA engineers devised a solution so Space Shuttle flights could cross the year-end boundary.<ref name="YERO">{{cite web |last=Bergin |first=Chris |title=NASA solves YERO problem for Shuttle |url=http://www.nasaspaceflight.com/content/?cid=5026|website=NASASpaceflight.com |archive-url=https://web.archive.org/web/20080418182718/http://www.nasaspaceflight.com/content/?cid=5026 |archive-date=April 18, 2008 |date= February 19, 2007 |access-date=December 22, 2007}}</ref>

Space Shuttle missions typically brought a portable general support computer (PGSC) that could integrate with the orbiter vehicle's computers and communication suite, as well as monitor scientific and payload data. Early missions brought the [[Grid Compass]], one of the first laptop computers, as the PGSC, but later missions brought [[Apple Inc.|Apple]] and [[Intel]] laptops.<ref name=jenkins />{{rp|408}}<ref name="GRiD">{{cite web |url=http://www.computerhistory.org/events/index.php?id=1139464298 |title=Pioneering the Laptop: Engineering the GRiD Compass |access-date=October 25, 2007 |publisher=The Computer History Museum |year=2006 |author=The Computer History Museum |url-status=dead |archive-url=https://web.archive.org/web/20071204034101/http://www.computerhistory.org/events/index.php?id=1139464298 |archive-date=December 4, 2007}}</ref>

====Payload bay====
[[File:Hubble First Servicing EVA - GPN-2000-001085.jpg|thumb|right|alt=An astronaut conducting an EVA while the Hubble Space Telescope is in the payload bay|[[Story Musgrave]] attached to the RMS servicing the [[Hubble Space Telescope]] during [[STS-61]]]]
[[File:STS132 Atlantis undocking2 (cropped).jpg|thumb|right|''[[Space Shuttle Atlantis|Atlantis]]'' in orbit in 2010. Image shows the payload bay and the extended [[Canadarm]].]]

The payload bay comprised most of the orbiter vehicle's [[fuselage]], and provided the cargo-carrying space for the Space Shuttle's payloads. It was {{convert|60|ft|m|sigfig=2|sp=us|order=flip|adj=on|abbr=on}} long and {{convert|15|ft|m|sigfig=2|sp=us|order=flip|adj=on|abbr=on}} wide, and could accommodate cylindrical payloads up to {{convert|15|ft|m|sigfig=2|sp=us|order=flip|adj=on|abbr=on}} in diameter. Two payload bay doors hinged on either side of the bay, and provided a relatively airtight seal to protect payloads from heating during launch and reentry. Payloads were secured in the payload bay to the attachment points on the [[longeron]]s. The payload bay doors served an additional function as radiators for the orbiter vehicle's heat, and were opened upon reaching orbit for heat rejection.<ref name=shuttle_manual/>{{rp|62–64}}

The orbiter could be used in conjunction with a variety of add-on components depending on the mission. This included orbital laboratories,<ref name=jenkins2016 />{{rp|II-304, 319}} boosters for launching payloads farther into space,<ref name=jenkins2016 />{{rp|II-326}} the Remote Manipulator System (RMS),<ref name=jenkins2016 />{{rp|II-40}} and optionally the EDO pallet to extend the mission duration.<ref name=jenkins2016 />{{rp|II-86}} To limit the fuel consumption while the orbiter was docked at the ISS, the [[Station-to-Shuttle Power Transfer System]] (SSPTS) was developed to convert and transfer station power to the orbiter.<ref name=jenkins2016 />{{rp|II-87–88}} The SSPTS was first used on STS-118, and was installed on ''Discovery'' and ''Endeavour''.<ref name=jenkins2016 />{{rp|III-366–368}}

====Remote Manipulator System====
{{main|Canadarm}}

The Remote Manipulator System (RMS), also known as Canadarm, was a mechanical arm attached to the cargo bay. It could be used to grasp and manipulate payloads, as well as serve as a mobile platform for astronauts conducting an EVA. The RMS was built by the Canadian company [[Spar Aerospace]] and was controlled by an astronaut inside the orbiter's flight deck using their windows and closed-circuit television. The RMS allowed for six degrees of freedom and had six joints located at three points along the arm. The original RMS could deploy or retrieve payloads up to {{convert|65000|lb|kg|sigfig=2|sp=us|order=flip|abbr=on}}, which was later improved to {{convert|586000|lb|kg|sigfig=2|sp=us|order=flip|abbr=on}}.<ref name=jenkins />{{rp|384–385}}

====Spacelab====
{{main|Spacelab}}
[[File:STS-9 Spacelab 1.jpg|thumb|alt=Spacelab in the payload bay while in orbit|[[Spacelab]] in orbit on [[STS-9]]]]

The Spacelab module was a European-funded pressurized laboratory that was carried within the payload bay and allowed for scientific research while in orbit. The Spacelab module contained two {{convert|9|ft|m|sigfig=2|abbr=on|order=flip}} segments that were mounted in the aft end of the payload bay to maintain the center of gravity during flight. Astronauts entered the Spacelab module through a {{convert|8.72|or|18.88|ft|m|sigfig=2|abbr=on|order=flip}} tunnel that connected to the airlock. The Spacelab equipment was primarily stored in pallets, which provided storage for both experiments as well as computer and power equipment.<ref name=jenkins />{{rp|434–435}} Spacelab hardware was flown on 28 missions through 1999 and studied subjects including astronomy, microgravity, radar, and life sciences. Spacelab hardware also supported missions such as Hubble Space Telescope (HST) servicing and space station resupply. The Spacelab module was tested on STS-2 and STS-3, and the first full mission was on STS-9.<ref name=NASA28>{{cite web |url=https://science.nasa.gov/science-news/science-at-nasa/1999/msad15mar99_1/ |title=Spacelab joined diverse scientists and disciplines on 28 Shuttle missions |last=Dooling |first=Dave |publisher=NASA |date=March 15, 1999 |access-date=April 23, 2020 |archive-date=December 24, 2018 |archive-url=https://web.archive.org/web/20181224003720/https://science.nasa.gov/science-news/science-at-nasa/1999/msad15mar99_1/ |url-status=live}}</ref>

====RS-25 engines====
{{main|RS-25}}
[[File:STS-133 Rendezvous Pitch Maneuver 3.jpg|thumb|alt=The two engine systems at the aft-section of the orbiter|[[RS-25]] engines with the two [[Orbital Maneuvering System]] (OMS) pods during [[STS-133]]]]

Three RS-25 engines, also known as the Space Shuttle Main Engines (SSME), were mounted on the orbiter's aft fuselage in a triangular pattern. The engine nozzles could gimbal ±10.5° in pitch, and ±8.5° in [[Aircraft principal axes#Vertical axis (yaw)|yaw]] during ascent to change the direction of their thrust to steer the Shuttle. The [[titanium alloy]] reusable engines were independent of the orbiter vehicle and would be removed and replaced in between flights. The RS-25 is a staged-combustion cycle cryogenic engine that used liquid oxygen and hydrogen and had a higher chamber pressure than any previous liquid-fueled rocket. The original main combustion chamber operated at a maximum pressure of {{convert|3285|psi|bar|sigfig=4|sp=us|order=flip|adj=off|abbr=on}}. The engine nozzle is {{convert|113|in|cm|sigfig=3|sp=us|order=flip|adj=off|abbr=on}} tall and has an interior diameter of {{convert|90.3|in|cm|sigfig=3|sp=us|order=flip|adj=off|abbr=on}}. The nozzle is cooled by 1,080 interior lines carrying liquid hydrogen and is thermally protected by insulative and ablative material.<ref name=jenkins2016 />{{rp|II–177–183}}

The RS-25 engines had several improvements to enhance reliability and power. During the development program, Rocketdyne determined that the engine was capable of safe reliable operation at 104% of the originally specified thrust. To keep the engine thrust values consistent with previous documentation and software, NASA kept the originally specified thrust at 100%, but had the RS-25 operate at higher thrust. RS-25 upgrade versions were denoted as Block I and Block II. 109% thrust level was achieved with the Block II engines in 2001, which reduced the chamber pressure to {{convert|3010|psi|bar|sigfig=4|sp=us|order=flip|adj=off}}, as it had a larger [[de Laval nozzle|throat]] area. The normal maximum throttle was 104 percent, with 106% or 109% used for mission aborts.<ref name=shuttle_manual />{{rp|106–107}}

====Orbital Maneuvering System====
{{main|Space Shuttle Orbital Maneuvering System}}

The Orbital Maneuvering System (OMS) consisted of two aft-mounted [[AJ10|AJ10-190]] engines and the associated propellant tanks. The AJ10 engines used [[monomethylhydrazine]] (MMH) oxidized by [[dinitrogen tetroxide]] (N<sub>2</sub>O<sub>4</sub>). The pods carried a maximum of {{convert|4718|lb|kg|order=flip|abbr=on|sigfig=4|sp=us}} of MMH and {{convert|7773|lb|kg|order=flip|abbr=on|sigfig=4|sp=us}} of N<sub>2</sub>O<sub>4</sub>. The OMS engines were used after main engine cut-off (MECO) for orbital insertion. Throughout the flight, they were used for orbit changes, as well as the deorbit burn prior to reentry. Each OMS engine produced {{convert|6087|lbf|N|order=flip|abbr=on|sigfig=4|sp=us}} of thrust, and the entire system could provide {{convert|1000|ft/s|m/s|order=flip|abbr=on|sigfig=3|sp=us}} of [[Delta-v|velocity change]].<ref name=jenkins2016 />{{rp|II–80}}

====Thermal protection system====
{{main|Space Shuttle thermal protection system}}

The orbiter was protected from heat during reentry by the thermal protection system (TPS), a [[Atmospheric entry#Thermal soak|thermal soaking]] protective layer around the orbiter. In contrast with previous US spacecraft, which had used ablative heat shields, the reusability of the orbiter required a multi-use heat shield.<ref name=shuttle_manual />{{rp|72–73}} During reentry, the TPS experienced temperatures up to {{convert|3000|F|C|sigfig=2|abbr=on|order=flip}}, but had to keep the orbiter vehicle's aluminum skin temperature below {{convert|350|F|C|sigfig=2|abbr=on|order=flip}}. The TPS primarily consisted of four types of tiles. The nose cone and leading edges of the wings experienced temperatures above {{convert|2300|F|C|sigfig=2|abbr=on|order=flip}}, and were protected by reinforced carbon-carbon tiles (RCC). Thicker RCC tiles were developed and installed in 1998 to prevent damage from [[space debris|micrometeoroid and orbital debris]], and were further improved after RCC damage caused in the [[Space Shuttle Columbia disaster|''Columbia'' disaster]]. Beginning with [[STS-114]], the orbiter vehicles were equipped with the wing leading edge impact detection system to alert the crew to any potential damage.<ref name=jenkins2016 />{{rp|II–112–113}} The entire underside of the orbiter vehicle, as well as the other hottest surfaces, were protected with tiles of high-temperature reusable surface insulation, made of [[borosilicate glass]]-coated [[silica]] fibers that trapped heat in air pockets and redirected it out. Areas on the upper parts of the orbiter vehicle were coated in tiles of white low-temperature reusable surface insulation with similar composition, which provided protection for temperatures below {{convert|1200|F|C|sigfig=2|abbr=on|order=flip}}. The payload bay doors and parts of the upper wing surfaces were coated in reusable [[Nomex]] felt surface insulation or in [[beta cloth]], as the temperature there remained below {{convert|700|F|C|sigfig=2|abbr=on|order=flip}}.<ref name=jenkins />{{rp|395}}

===External tank===
{{main|Space Shuttle external tank}}
[[File:External_Tank.jpg|right|thumb|The ET from [[STS-115]] after separation from the orbiter. The scorch mark near the front end of the tank is from the SRB separation motors.]]
The Space Shuttle external tank (ET) carried the propellant for the Space Shuttle Main Engines, and connected the orbiter vehicle with the solid rocket boosters. The ET was {{convert|153.8|ft|m|sigfig=2|abbr=on|order=flip}} tall and {{convert|27.6|ft|m|sigfig=2|abbr=on|order=flip}} in diameter, and contained separate tanks for liquid oxygen and liquid hydrogen. The liquid oxygen tank was housed in the nose of the ET, and was {{convert|49.3|ft|m|sigfig=2|abbr=on|order=flip}} tall. The liquid hydrogen tank comprised the bulk of the ET, and was {{convert|96.7|ft|m|sigfig=2|abbr=on|order=flip}} tall. The orbiter vehicle was attached to the ET at two umbilical plates, which contained five propellant and two electrical umbilicals, and forward and aft structural attachments. The exterior of the ET was covered in orange spray-on foam to allow it to survive the heat of ascent.{{r|jenkins|p=421–422}}

The ET provided propellant to the Space Shuttle Main Engines from liftoff until main engine cutoff. The ET separated from the orbiter vehicle 18 seconds after engine cutoff and could be triggered automatically or manually. At the time of separation, the orbiter vehicle retracted its umbilical plates, and the umbilical cords were sealed to prevent excess propellant from venting into the orbiter vehicle. After the bolts attached at the structural attachments were sheared, the ET separated from the orbiter vehicle. At the time of separation, gaseous oxygen was vented from the nose to cause the ET to tumble, ensuring that it would break up upon reentry. The ET was the only major component of the Space Shuttle system that was not reused, and it would travel along a ballistic trajectory into the Indian or Pacific Ocean.<ref name=jenkins />{{rp|422}}

For the first two missions, STS-1 and [[STS-2]], the ET was covered in {{convert|595|lb|kg|sigfig=2|abbr=on|order=flip}} of white fire-retardant latex paint to provide protection against damage from ultraviolet radiation. Further research determined that the orange foam itself was sufficiently protected, and the ET was no longer covered in latex paint beginning on STS-3.<ref name=jenkins2016 />{{rp|II-210}} A light-weight tank (LWT) was first flown on STS-6, which reduced tank weight by {{convert|10300|lb|kg|sigfig=2|abbr=on|order=flip}}. The LWT's weight was reduced by removing components from the hydrogen tank and reducing the thickness of some skin panels.<ref name=jenkins />{{rp|422}} In 1998, a super light-weight ET (SLWT) first flew on [[STS-91]]. The SLWT used the 2195 aluminum-lithium alloy, which was 40% stronger and 10% less dense than its predecessor, 2219 aluminum-lithium alloy. The SLWT weighed {{convert|7500|lb|kg|sigfig=2|abbr=on|order=flip}} less than the LWT, which allowed the Space Shuttle to deliver heavy elements to ISS's high inclination orbit.<ref name=jenkins />{{rp|423–424}}

===Solid Rocket Boosters===
{{main|Space Shuttle Solid Rocket Booster}}
[[File:Two Space Shuttle SRBs on the Crawler transporter.jpg|thumb|right|alt=Two Solid Rocket Boosters that are not attached to an external tank or orbiter|Two SRBs on the mobile launcher platform prior to mating with the ET and orbiter for [[STS-134]]]]

The Solid Rocket Boosters (SRB) provided 71.4% of the Space Shuttle's thrust during liftoff and ascent, and were the largest [[solid-propellant motor]]s ever flown.<ref name=SRB_largest>{{cite web |url=http://www.nasa.gov/returntoflight/system/system_SRB.html |title=Solid Rocket Boosters |publisher=NASA |date=March 5, 2006 |last=Dunbar |first=Brian |access-date=July 19, 2021 |archive-date=April 6, 2013 |archive-url=https://web.archive.org/web/20130406193019/http://www.nasa.gov/returntoflight/system/system_SRB.html |url-status=live}}</ref> Each SRB was {{convert|149.2|ft|m|abbr=on|order=flip|sigfig=2}} tall and {{convert|12.2|ft|m|abbr=on|order=flip|sigfig=2}} wide, weighed {{convert|150000|lb|kg|abbr=on|order=flip|sigfig=3}}, and had a steel exterior approximately {{convert|.5|in|mm|abbr=on|order=flip|sigfig=2}} thick. The SRB's subcomponents were the solid-propellant motor, nose cone, and rocket nozzle. The solid-propellant motor comprised the majority of the SRB's structure. Its casing consisted of 11 steel sections which made up its four main segments. The nose cone housed the forward separation motors and the parachute systems that were used during recovery. The rocket nozzles could gimbal up to 8° to allow for in-flight adjustments.<ref name=jenkins />{{rp|425–429}}

The rocket motors were each filled with a total {{convert|1106640|lb|kg|abbr=on|order=flip|sigfig=2}} of solid rocket propellant ([[Ammonium perchlorate composite propellant|APCP]]+[[Polybutadiene acrylonitrile|PBAN]]), and joined in the [[Vehicle Assembly Building]] (VAB) at KSC.<ref name=jenkins />{{rp|425–426}} In addition to providing thrust during the first stage of launch, the SRBs provided structural support for the orbiter vehicle and ET, as they were the only system that was connected to the [[mobile launcher platform]] (MLP).<ref name=jenkins />{{rp|427}} At the time of launch, the SRBs were armed at T−5&nbsp;minutes, and could only be electrically ignited once the RS-25 engines had ignited and were without issue.<ref name=jenkins />{{rp|428}} They each provided {{convert|2800000|lbf|kN|abbr=on|order=flip|sigfig=3}} of thrust, which was later improved to {{convert|3000000|lbf|kN|abbr=on|order=flip|sigfig=3}} beginning on [[STS-8]].<ref name=jenkins />{{rp|425}} After expending their fuel, the SRBs were [[Jettison (aviation)|jettisoned]] approximately two minutes after launch at an altitude of approximately {{convert|150000|ft|km|sigfig=2|abbr=on|order=flip}}. Following separation, they deployed drogue and main parachutes, landed in the ocean, and were recovered by the crews aboard the ships [[MV Freedom Star|MV ''Freedom Star'']] and [[MV Liberty Star|MV ''Liberty Star'']].<ref name=jenkins />{{rp|430}} Once they were returned to Cape Canaveral, they were cleaned and disassembled. The rocket motor, igniter, and nozzle were then shipped to Thiokol to be refurbished and reused on subsequent flights.<ref name=shuttle_manual />{{rp|124}}

The SRBs underwent several redesigns throughout the program's lifetime. [[STS-6]] and [[STS-7]] used SRBs {{convert|5000|lb|kg|abbr=on|order=flip|sigfig=2}} lighter due to walls that were {{convert|.004|in|mm|abbr=on|order=flip|sigfig=2}} thinner, but were determined to be too thin to fly safely. Subsequent flights until [[STS-26]] used cases that were {{convert|.003|in|mm|abbr=on|order=flip|sigfig=2}} thinner than the standard-weight cases, which reduced {{convert|4000|lb|kg|abbr=on|order=flip|sigfig=2}}. After the ''Challenger'' disaster as a result of an [[O-ring]] failing at low temperature, the SRBs were redesigned to provide a constant seal regardless of the ambient temperature.<ref name=jenkins />{{rp|425–426}}

===Support vehicles===
[[File:Freedom Star SRB recovery.jpg|thumb|right|alt=A recovery boat with a recovered Solid Rocket Booster|MV ''Freedom Star'' towing a spent SRB (STS-133) to Cape Canaveral Air Force Station]]

The Space Shuttle's operations were supported by vehicles and infrastructure that facilitated its transportation, construction, and crew access. The [[crawler-transporter]]s carried the MLP and the Space Shuttle from the VAB to the launch site.<ref name="crawler">{{cite web |url=https://science.ksc.nasa.gov/facilities/crawler.html |title=Crawler-Transporter |publisher=NASA |date=April 21, 2003 |access-date=June 18, 2020 |archive-date=June 1, 2020 |archive-url=https://web.archive.org/web/20200601012639/https://science.ksc.nasa.gov/facilities/crawler.html |url-status=live}}</ref> The [[Shuttle Carrier Aircraft]] (SCA) were two modified [[Boeing 747]]s that could carry an orbiter on its back. The original SCA (N905NA) was first flown in 1975, and was used for the [[Approach and Landing Tests|ALT]] and ferrying the orbiter from Edwards AFB to the KSC on all missions prior to 1991. A second SCA (N911NA) was acquired in 1988, and was first used to transport ''Endeavour'' from the factory to the KSC. Following the retirement of the Space Shuttle, N905NA was put on display at the JSC, and N911NA was put on display at the [[Joe Davies Heritage Airpark]] in [[Palmdale, California]].<ref name="jenkins2016"/>{{rp|I–377–391}}<ref name="joe_davies">{{cite web |title=Joe Davies Heritage Airpark |publisher=[[Palmdale, California|City of Palmdale]] |url=https://www.cityofpalmdale.org/DocumentCenter/View/265/Joe-Davies-Heritage-Airpark-Brochure-PDF |access-date=June 18, 2020 |archive-date=August 7, 2020 |archive-url=https://web.archive.org/web/20200807082227/https://www.cityofpalmdale.org/DocumentCenter/View/265/Joe-Davies-Heritage-Airpark-Brochure-PDF |url-status=live}}</ref> The [[mobile lounge#NASA Crew Transport Vehicles|Crew Transport Vehicle]] (CTV) was a modified airport [[jet bridge]] that was used to assist astronauts to egress from the orbiter after landing, where they would undergo their post-mission medical checkups.<ref name="ctv">{{cite web |last=Chowdhury |first=Abul |title=Crew Transport Vehicle |publisher=NASA |date=October 10, 2018 |url=https://lsda.jsc.nasa.gov/Hardware/hardw/873 |access-date=June 18, 2020 |archive-date=August 7, 2020 |archive-url=https://web.archive.org/web/20200807103823/https://lsda.jsc.nasa.gov/Hardware/hardw/873 |url-status=live}}</ref> The [[Astronaut transfer van|Astrovan]] transported astronauts from the crew quarters in the Operations and Checkout Building to the launch pad on launch day.<ref name="astrovan">{{cite web |url=http://www.nasa.gov/mission_pages/shuttle/behindscenes/astrovan.html |title=Catching a Ride to Destiny |publisher=NASA |first=Cheryl L. |last=Mansfield |date=July 15, 2008 |access-date=June 18, 2020 |archive-date=June 9, 2009 |archive-url=https://web.archive.org/web/20090609095623/http://www.nasa.gov/mission_pages/shuttle/behindscenes/astrovan.html |url-status=live}}</ref> The [[NASA Railroad]] comprised three locomotives that transported SRB segments from the [[Florida East Coast Railway]] in [[Titusville, Florida|Titusville]] to the KSC.<ref name="railroad">{{cite web |title=The NASA Railroad |publisher=NASA |date=2007 |url=https://www.nasa.gov/centers/kennedy/pdf/192935main_RRtrain08.pdf |access-date=June 18, 2020 |archive-date=August 7, 2020 |archive-url=https://web.archive.org/web/20200807073843/https://www.nasa.gov/centers/kennedy/pdf/192935main_RRtrain08.pdf |url-status=live}}</ref>