[8]:142[9]:16–18, In September 1966, NASA and the Air Force released a joint study concluding that a new vehicle was required to satisfy their respective future demands, and that a partially reusable system would be the most cost-effective solution. [44], The partial reusability of the Space Shuttle was one of the primary design requirements during its initial development. NASA chose to use ceramic tiles for thermal protection, as the shuttle could then be constructed of lightweight aluminum, and the tiles could be individually replaced as needed. [45][14]:III–489–490 The Space Shuttle was originally intended as a launch vehicle to deploy satellites, which it was primarily used for on the missions prior to the Challenger disaster. Finally, once the orbiter's wheels became motionless, the crew deactivated the flight components and prepared to exit. The initial design of the reusable Space Shuttle envisioned an increasingly cheap launch platform to deploy commercial and government satellites. The GPCs controlled ET separation, and dumped the remaining LOX and LH2 to prevent outgassing while in orbit. [14]:III-443 Atlantis is on display at the Kennedy Space Center Visitor Complex,[14]:III-456 Discovery is at the Udvar-Hazy Center,[14]:III-451 Endeavour is on display at the California Science Center,[14]:III-457 and Enterprise is displayed at the Intrepid Sea-Air-Space Museum. As S band radios can operate only within their 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. [42]:71 Repeated warnings from design engineers voicing concerns about the lack of evidence of the O-rings' safety when the temperature was below 53 °F (12 °C) had been ignored by NASA managers. 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. At T−0, the eight frangible nuts holding the SRBs to the pad were detonated, the final umbilicals were disconnected, the SSMEs were commanded to 100% throttle, and the SRBs were ignited. The pods carried a maximum of 2,140 kg (4,718 lb) of MMH and 3,526 kg (7,773 lb) of N2O4. [7]:170–173, On June 4, 1974, Rockwell began construction on the first orbiter, OV-101, which would later be named Enterprise. STS-6 and STS-7 used SRBs that were 2,300 kg (5,000 lb) lighter than the standard-weight cases due to walls that were 0.10 mm (.004 in) thinner, but were determined to be too thin. [9]:106–107, The Orbital Maneuvering System (OMS) consisted of two aft-mounted AJ10-190 engines and the associated propellant tanks. [7]:165–170, NASA reviewed 29 potential designs for the Space Shuttle, and determined that a design with two side boosters should be used, and the boosters should be reusable to reduce costs. Postal Service has released several postage issues that depict the Space Shuttle. Missions after STS-38 used the RS-25 engines to achieve the optimal apogee, and used the OMS engines to circularize the orbit. [6], During the 1950s, the United States Air Force proposed using a reusable piloted glider to perform military operations such as reconnaissance, satellite attack, and air-to-ground weapons employment. Support generously provided by Meredith Siegfried Madden and Dr. Peter Madden. [46] Early safety analyses advertised by NASA engineers and management predicted the chance of a catastrophic failure resulting in the death of the crew as ranging from 1 in 100 launches to as rare as 1 in 100,000. [19], 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. [14]:III–13, In addition to the pre-planned landing airfields, there were 85 agreed-upon emergency landing sites to be used in different abort scenarios, with 58 located in other countries. [18]:403–404, The Space Shuttle's fly-by-wire control system was entirely reliant on its main computer, the Data Processing System (DPS). [14]:III–140 Beginning with STS-74, the orbiter vehicle conducted dockings with the Mir space station. 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. [14]:III-355 STS-135 launched on July 8, 2011, and landed at the KSC on July 21, 2011, at 5:57 a.m. EDT (09:57 UTC). The crawler-transporters carried the MLP and the Space Shuttle from the VAB to the launch site. However, the Columbia disaster resulted in additional orbiters being prepared for launch on need in the event of a rescue mission. At 8 minutes 44 seconds prior to landing, the crew deployed the air data probes, and began lowering the angle-of-attack to 36°. [7]:173[13] Rockwell constructed the Main Propulsion Test Article (MPTA)-098, which was a structural truss mounted to the ET with three RS-25 engines attached. [18]:425–426, The Space Shuttle's operations were supported by vehicles and infrastructure that facilitated its transportation, construction, and crew access. The original main combustion chamber operated at a maximum pressure of 226.5 bar (3,285 psi). The improvement of expendable launch vehicles and the transition away from commercial payload on the Space Shuttle resulted in expendable launch vehicles becoming the primary deployment option for satellites. [7]:164 The technical decisions that dictated the orbiter's return and reuse reduced the per-launch payload capabilities with the intention of lowering the per-launch costs and resulting in a high-launch rate. 109% thrust level was achieved with the Block II engines in 2001, which reduced the chamber pressure to 207.5 bars (3,010 psi), as it had a larger throat area. [7]:166, After they established the need for a reusable, heavy-lift spacecraft, NASA and the Air Force determined the design requirements of their respective services. [18]:422, For the first two missions, STS-1 and STS-2, the ET was covered in 270 kg (595 lb) of white fire-retardant latex paint to provide protection against damage from ultraviolet radiation. [18]:365 Its three-part fuselage provided support for the crew compartment, cargo bay, flight surfaces, and engines. [26] The Astrovan transported astronauts from the crew quarters in the Operations and Checkout Building to the launch pad on launch day. Both seats also had rudder controls, to allow rudder movement in flight and nose-wheel steering on the ground. The Space Shuttle was the first operational orbital spacecraft designed for reuse. Once installed at the launch pad, the Space Shuttle was used to verify the proper positioning of launch complex hardware. [39], The Space Shuttle flew from April 12, 1981[14]:III–24 until July 21, 2011. 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 rocket. Orbiter is a simulator that gives you an idea what space flight really feels like - today and in the not so distant future. In 1982, NASA published an estimate of $260 million (in 2012) per flight, which was based on the prediction of 24 flights per year for a decade. The ET separated from the orbiter vehicle 18 seconds after engine cutoff, and could be triggered automatically or manually. [42]:148, On February 1, 2003, Columbia disintegrated during re-entry, killing all seven of the STS-107 crew, because of damage to the carbon-carbon leading edge of the wing caused during launch. Visit the IIIF page to learn more. Partially reusable launch system and spacecraft, This article is about a spacecraft system used by NASA. [14]:III–8 LOX and LH2 were loaded into the external tank via umbilicals that attached to the orbiter vehicle, which began at T−5 hours 35 minutes. [9]:132–133 Once the entire stack was assembled, the MLP was carried for 5.6 km (3.5 mi) to Launch Complex 39 by one of the crawler-transporters. 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. If all three engines indicated nominal performance by T−3 seconds, they were commanded to gimbal to liftoff configuration and the command would be issued to arm the SRBs for ignition at T−0. The vast reaches of our solar system are open for Orbiter fans to explore. During reentry, the crew deployed two air data probes once they were traveling slower than Mach 5. The RMS allowed for six degrees of freedom, and had six joints located at three points along the arm. [14]:II–80, The orbiter was protected from heat during reentry by the thermal protection system (TPS), a thermal soaking protective layer around the orbiter. 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. [18]:370–371, The flight deck was the top level of the crew compartment, and contained the flight controls for the orbiter. For more information, visit the Smithsonian's, International media Interoperability Framework. The orbiter was protected during reentry by its thermal protection system tiles, and it glided as a spaceplane to a runway landing, usually to the Shuttle Landing Facility at KSC, Florida, or to Rogers Dry Lake in Edwards Air Force Base, California. In addition to the weather at the launch site, conditions had to be acceptable at one of the Transatlantic Abort Landing sites and the SRB recovery area. Orbiter is a unique flight simulator that lets users launch manned or unmanned flights into space. In January 1972, President Richard Nixon approved the Shuttle, and NASA decided on its final design in March. RS-25 upgrade versions were denoted as Block I and Block II. The rising costs of development and the prioritization of Project Gemini led to the cancellation of the Dyna-Soar program in December 1963. [14]:III–9–10, Early missions used two firings of the OMS to achieve orbit; the first firing raised the apogee while the second circularized the orbit. [9]:62–64, The orbiter could be used in conjunction with a variety of add-on components depending on the mission. The orbiter's vertical stabilizer was swept backwards at 45°, and contained a rudder that could split to act as a speed brake. [14]:III-352 Originally, STS-134 was to be the final Space Shuttle mission. The orbiter vehicle's aft RCS jets were disabled as it descended and its ailerons, elevators, and rudder became effective in the lower atmosphere. The orbiter was also equipped with two UHF radios for communications with air traffic control and astronauts conducting EVA. Each Space Shuttle orbiter was designed for a projected lifespan of 100 launches or ten years of operational life, although this was later extended. [14]:II–26–33, The orbiter was equipped with an avionics system to provide information and control during atmospheric flight. [14]:III–224 In its final decade of operation, the Space Shuttle was used for the construction of the International Space Station. [14]:III−491 Per-launch costs varied throughout the program, and were dependent on the rate of flights as well as research, development, and investigation proceedings throughout the Space Shuttle program. [14]:III−489−490 Development estimates made in 1972 projected a per-pound cost of payload as low as $1,109 (in 2012) per pound, but the actual payload costs, not to include the costs for the research and development of the Space Shuttle, were $37,207 (in 2012) per pound. [29] The Space Shuttle was not launched under conditions where it could have been struck by lightning, as its exhaust plume could have triggered lightning by providing a current path to ground after launch, which occurred on Apollo 12. [18]:434–435 Spacelab hardware was flown on 28 missions through 1999, and studied subjects including astronomy, microgravity, radar, and life sciences. Construction of OV-105, later named Endeavour, began in February 1982, but NASA decided to limit the Space Shuttle fleet to four orbiters in 1983. The facilities were prepared with equipment and personnel in the event of an emergency shuttle landing, but were never used. In contrast with previous US spacecraft, which had used ablative heat shields, the reusability of the orbiter required a multi-use heat shield. Spacelab hardware also supported missions such as Hubble Space Telescope (HST) servicing and space station resupply. The actual costs of a Space Shuttle launch were higher than initially predicted, and the Space Shuttle did not fly the intended 24 missions per year as initially predicted by NASA. In September 1969, the Space Task Group, under leadership of Vice President Spiro Agnew, issued a report calling for the development of a space shuttle to bring people and cargo to low Earth orbit (LEO), as well as a space tug for transfers between orbits and the Moon, and a reusable nuclear upper stage for deep space travel. In January 1971, NASA and Air Force leadership decided that a reusable delta-wing orbiter mounted on an expendable propellant tank would be the optimal design for the Space Shuttle.