Titan IV was a family of heavy-lift space launch vehicles developed by Martin Marietta and operated by the United States Air Force from 1989 to 2005. Launches were conducted from Cape Canaveral Air Force Station , Florida and Vandenberg Air Force Base , California.
102-658: The Titan IV was the last of the Titan family of rockets , originally developed by the Glenn L. Martin Company in 1958. It was retired in 2005 due to their high cost of operation and concerns over its toxic hypergolic propellants , and replaced with the Atlas V and Delta IV launch vehicles under the EELV program. The final launch (B-30) from Cape Canaveral occurred on 29 April 2005, and
204-725: A Defense Meteorological Satellite Program (DMSP) weather satellite on 18 October 2003. The Titan III was a modified Titan II with optional solid rocket boosters . It was developed on behalf of the United States Air Force (USAF) as a heavy-lift satellite launcher to be used mainly to launch American military payloads and civilian intelligence agency satellites such as the Vela Hotel nuclear-test-ban monitoring satellites, observation and reconnaissance satellites (for intelligence-gathering), and various series of defense communications satellites. As USAF project, Titan III
306-616: A Delco Carousel VB IMU and MAGIC 352 Missile Guidance Computer (MGC). The Titan IIIA was a prototype rocket booster and consisted of a standard Titan II rocket with a Transtage upper stage. The Titan IIIB with its different versions (23B, 24B, 33B, and 34B) had the Titan III core booster with an Agena D upper stage. This combination was used to launch the KH-8 GAMBIT series of intelligence-gathering satellites. They were all launched from Vandenberg Air Force Base, due south over
408-553: A crater 250 feet (76 m) in diameter. The 54 Titan IIs in Arizona, Arkansas, and Kansas were replaced by 50 MX "Peacekeeper" solid-fuel rocket missiles in the mid-1980s; the last Titan II silo was deactivated in May 1987. The 54 Titan IIs had been fielded along with a thousand Minuteman missiles from the mid-1960s through the mid-1980s. A number of Titan I and Titan II missiles have been distributed as museum displays across
510-419: A nose cone . The nose cone consists of a removable conical assembly that serves as an aerodynamic fairing for the propulsion and electrical system components. The foremost element of the nose cone functions as a cast aluminium lightning rod. The LOX tank volume is 19,744 cu ft (559.1 m ) at 22 psi (150 kPa) and −297 °F (90.4 K; −182.8 °C) ( cryogenic ). The tank feeds into
612-576: A 17 in (430 mm) diameter feed line that conveys the liquid oxygen through the intertank, then outside the ET to the aft right-hand ET/orbiter disconnect umbilical. The 17 in (430 mm) diameter feed line permits liquid oxygen to flow at approximately 2,787 lb/s (75,800 kg/min) with the RS-25s operating at 104% or permits a maximum flow of 17,592 US gal/min (1.1099 m /s). All loads except aerodynamic loads are transferred from
714-473: A NOSS SIGNIT satellite. Unusually for DoD launches, the Air Force invited civilian press to cover the launch, which became more of a story than intended when the booster exploded 101 seconds after liftoff. Investigation found that one of the two SRMs had burned through, resulting in the destruction of the vehicle in a similar manner as the earlier 34D-9 failure. An investigation found that an improper repair job
816-650: A family of United States expendable rockets used between 1959 and 2005. The Titan I and Titan II were part of the US Air Force 's intercontinental ballistic missile (ICBM) fleet until 1987. The space launch vehicle versions contributed the majority of the 368 Titan launches, including all the Project Gemini crewed flights of the mid-1960s. Titan vehicles were also used to lift US military payloads as well as civilian agency reconnaissance satellites and to send interplanetary scientific probes throughout
918-588: A further consideration. Lockheed Martin decided to extend its Atlas family of rockets instead of its more expensive Titans, along with participating in joint-ventures to sell launches on the Russian Proton rocket and the new Boeing -built Delta IV class of medium and heavy-lift launch vehicles. The Titan IVB was the last Titan rocket to remain in service, making its penultimate launch from Cape Canaveral on 30 April 2005, followed by its final launch from Vandenberg Air Force Base on 19 October 2005, carrying
1020-635: A hardened underground bunker. Using radar data, it made course corrections during the burn phase. Unlike decommissioned Thor, Atlas, and Titan II missiles, the Titan I inventory was scrapped and never reused for space launches or RV tests, as all support infrastructure for the missile had been converted to the Titan II/III family by 1965. Most of the Titan rockets were the Titan II ICBM and their civilian derivatives for NASA . The Titan II used
1122-473: A location often used for launch into non-polar orbits. The Titan V was a proposed development of the Titan IV, that saw several designs being suggested. One Titan V proposal was for an enlarged Titan IV, capable of lifting up to 90,000 pounds (41,000 kg) of payload. Another used a cryogenic first stage with LOX/LH2 propellants; however the Atlas V EELV was selected for production instead. Most of
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#17327867732371224-628: A modified Centaur G-Prime stage to rendezvous and dock. The plan required upgrading the Space Shuttle and Titan IV to use lighter aluminium-lithium alloy propellant tanks. The plan never came to fruition, but in the 1990s the Shuttle's External Tank was converted to aluminum-lithium tanks to rendezvous with the highly inclined orbit of the Russian Mir Space Station . The IV-A (40nA) used boosters with steel casings,
1326-533: A momentary power dropout to the guidance computer at T+39 seconds. After power was restored, the computer sent a spurious pitch down and yaw to the right command. At T+40 seconds, the Titan was traveling at near supersonic speed and could not handle this action without suffering a structural failure. The sudden pitch downward and resulting aerodynamic stress caused one of the SRMs to separate. The ISDS (Inadvertent Separation Destruct System) automatically triggered, rupturing
1428-613: A number of other legacy launch systems. The new EELVs eliminated the use of hypergolic propellants, reduced costs, and were much more versatile than the legacy vehicles. In 2014, the National Museum of the United States Air Force in Dayton, Ohio , began a project to restore a Titan IV-B rocket. This effort was successful, with the display opening June 8, 2016. The only other surviving Titan IV components are at
1530-445: A piece of foam (and/or ice) about 3.9 in (100 mm) in diameter separated from a feedline attachment bracket on the tank, ricocheted off one of the aft struts and struck the underside of the wing, damaging two tiles. The damage was not considered dangerous. The external hardware, ET–orbiter attachment fittings, umbilical fittings, and electrical and range safety system weigh 9,100 pounds (4,100 kg). Each propellant tank has
1632-414: A separate, pyrotechnically operated, propulsive tumble vent valve at its forward end. At separation, the liquid oxygen tumble vent valve was opened, providing impulse to assist in the separation maneuver and more positive control of the entry aerodynamics of the ET. The last flight with the tumble valve active was STS-36. Each of the two aft external tank umbilical plates mate with a corresponding plate on
1734-534: A silo outside Rock, Kansas , an oxidizer transfer line carrying NTO ruptured on August 24, 1978. An ensuing orange vapor cloud forced 200 rural residents to evacuate the area. A staff sergeant of the maintenance crew was killed while attempting a rescue and a total of twenty were hospitalized. Another site at Potwin, Kansas leaked NTO oxidizer in April 1980 with no fatalities, and was later closed. In September 1980, at Titan II silo 374-7 near Damascus, Arkansas ,
1836-490: A space station as extra living or research space, as rocket fuel tanks for interplanetary missions (e.g. Mars), to raw materials for orbiting factories. Another concept was to use the ET as a cargo carrier for bulky payloads. One proposal was for the primary mirror of a 7-meter aperture telescope to be carried with the tank. Another concept was the Aft Cargo Carrier (ACC). Over the years, NASA worked to reduce
1938-409: A tanking test determined the cause of the errors to be a fault in a wiring connector, rather than a failure of the sensors themselves. Four pressure transducers located at the top of the liquid oxygen and liquid hydrogen tanks monitor the ullage pressures. The ET also has two electrical umbilicals that carry electrical power from the orbiter to the tank and the two SRBs and provide information from
2040-402: A technician dropped an 8 lb (3.6 kg) socket that fell 70 ft (21 m), bounced off a thrust mount, and broke the skin of the missile's first stage, over eight hours prior to an eventual explosion . The puncture occurred about 6:30 p.m. and when a leak was detected shortly after, the silo was flooded with water and civilian authorities were advised to evacuate the area. As
2142-420: A vent and relief valve at its forward end. This dual-function valve can be opened by ground support equipment for the vent function during prelaunch and can open during flight when the ullage (empty space) pressure of the liquid hydrogen tank reaches 38 psi (260 kPa) or the ullage pressure of the liquid oxygen tank reaches 25 psi (170 kPa). On early flights, the liquid oxygen tank contained
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#17327867732372244-459: Is an Al-Li alloy designed by Lockheed Martin and Reynolds for storage of cryogenics (and used for the SLW version of the ET - earlier versions used Al 2219 ). Al 2090 is a commercially available Al-Li alloy. The LOX tank is located at the top of the ET and has an ogive shape to reduce aerodynamic drag and aerothermodynamic heating. The ogive nose section is capped by a flat removable cover plate and
2346-622: Is needed. This allowed the launcher to be stored in a ready state for extended periods, but both propellants are extremely toxic. The Titan IV could be launched from either coast: SLC-40 or 41 at Cape Canaveral Air Force Station near Cocoa Beach, Florida and at SLC-4E , at Vandenberg Air Force Base launch sites 55 miles northwest of Santa Barbara California. Launches to polar orbits occurred from Vandenberg, with most other launches taking place at Cape Canaveral. Titan IV-A flew with steel-cased solid UA1207 rocket motors (SRMs) produced by Chemical Systems Division. The Titan IV-B evolved from
2448-472: Is vented through umbilical connections over a large diameter pipe on an arm extended from the fixed service structure. The connection for this pipe between the ET and service structure is made at the ground umbilical carrier plate (GUCP). Sensors are also installed at the GUCP to measure hydrogen levels. Countdowns of STS-80 , STS-119 , STS-127 and STS-133 have been halted and resulted in several week delays in
2550-735: The Charles Stark Draper Laboratory at MIT. The missile guidance computer (MGC) was the IBM ASC-15 . When spares for this system became hard to obtain, it was replaced by a more modern guidance system, the Delco Electronics Universal Space Guidance System (USGS). The USGS used a Carousel IV IMU and a Magic 352 computer. The USGS was already in use on the Titan III space launcher when work began in March 1978 to replace
2652-499: The Clean Air Act . In its place, a hydrochlorofluorocarbon known as HCFC-141b was certified for use and phased into the shuttle program. Remaining foams, particularly detail pieces sprayed by hand, continued to use CFC-11 through the end of the program. These areas include the problematic bipod and PAL ramps, as well as some fittings and interfaces. For the bipod ramp in particular, "the process of applying foam to that part of
2754-575: The LR-87-5 engine, a modified version of the LR-87 , that used a hypergolic propellant combination of nitrogen tetroxide (NTO) for its oxidizer and Aerozine 50 (a 50/50 mix of hydrazine and unsymmetrical dimethylhydrazine (UDMH) instead of the liquid oxygen and RP-1 propellant of the Titan I. The first Titan II guidance system was built by AC Spark Plug . It used an inertial measurement unit made by AC Spark Plug derived from original designs from
2856-747: The Wings Over the Rockies Air and Space Museum in Denver, Colorado which has two Titan Stage 1 engines, one Titan Stage 2 engine, and the interstage ‘skirt’ on outdoor display; and at the Evergreen Aviation and Space Museum in McMinnville, Oregon, including the core stages and parts of the solid rocket motor assembly. The Titan IV experienced four catastrophic launch failures. On August 2, 1993, Titan IV K-11 lifted from SLC-4E carrying
2958-426: The Air Force had put extreme pressure on launch crews to meet program deadlines. The Titan's fuselage was filled with numerous sharp metal protrusions that made it nearly impossible to install, adjust, or remove wiring without it getting damaged. Quality control at Lockheed's Denver plant, where Titan vehicles were assembled, was described as "awful". The proximal cause of the failure was an electrical short that caused
3060-578: The Air Force. The Titan IV could be launched with no upper stage , the Inertial Upper Stage (IUS), or the Centaur upper stage . The Titan IV was made up of two large solid-fuel rocket boosters and a two-stage liquid-fueled core. The two storable liquid fuel core stages used Aerozine 50 fuel and nitrogen tetroxide oxidizer. These propellants are hypergolic , igniting on contact, and are liquids at room temperature, so no tank insulation
3162-432: The ET, thus protecting the orbiter's thermal protection system during launch. There are eight propellant-depletion sensors, four each for fuel and oxidizer. The fuel-depletion sensors are located in the bottom of the fuel tank. The oxidizer sensors are mounted in the orbiter liquid oxygen feed line manifold downstream of the feed line disconnect. During RS-25 thrusting, the orbiter general-purpose computers constantly compute
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3264-621: The IV-B (40nB) used boosters with composite casings (the SRMU). Type 401 used a Centaur 3rd stage, type 402 used an IUS 3rd stage. The other 3 types (without 3rd stages) were 403, 404, and 405: The Titan rocket family was established in October 1955 when the Air Force awarded the Glenn L. Martin Company (later Martin-Marietta , now part of Lockheed Martin ) a contract to build an intercontinental ballistic missile ( SM-68 ). The resulting Titan I
3366-525: The LOX tank at a bolted, flange-joint interface with the intertank. The LOX tank also includes an internal slosh baffle and a vortex baffle to dampen fluid slosh. The vortex baffle is mounted over the LOX feed outlet to reduce fluid swirl resulting from slosh and to prevent entrapment of gases in the delivered LOX. The intertank is the ET structural connection between the LOX and LH 2 tanks. Its primary functions are to receive and distribute all thrust loads from
3468-511: The LOX). After propellant loading data from ground tests and the first few Space Shuttle missions were assessed, the anti-geyser line was removed for subsequent missions. The total length and diameter of the ET remain unchanged. The last SWT, flown on STS-7 , weighed approximately 77,000 pounds (35,000 kg) inert. Beginning with the STS-6 mission, a lightweight ET (LWT), was introduced. This tank
3570-619: The Pacific into polar orbits . Their maximum payload mass was about 7,500 lb (3,000 kg). The powerful Titan IIIC used a Titan III core rocket with two large strap-on solid-fuel boosters to increase its launch thrust and maximum payload mass. The solid-fuel boosters that were developed for the Titan IIIC represented a significant engineering advance over previous solid-fueled rockets, due to their large size and thrust, and their advanced thrust-vector control systems. The Titan IIID
3672-506: The RCS fuel was depleted, causing the upper stage and payload to rotate rapidly. On restart, the Centaur cartwheeled out of control and left its payload in a useless orbit. This failure was found to be the result of an incorrectly programmed equation in the guidance computer. The error caused the roll rate gyro data to be ignored by the flight computer. Titan (rocket family) Titan was
3774-485: The SRBs and ET to the orbiter. The ET has external cameras mounted in the brackets attached to the shuttle along with transmitters that can continue to send video data long after the shuttle and the ET have separated. Earlier tanks incorporated a range safety system to disperse tank propellants if necessary. It included a battery power source, a receiver/decoder, antennas and ordnance . Starting with STS-79 this system
3876-497: The SRBs and transfer loads between the tanks. The two SRB forward attach fittings are located 180° apart on the intertank structure. A beam is extended across the intertank structure and is mechanically fastened to the attach fittings. When the SRBs are firing, the beam will flex due to high stress loads. These loads will be transferred to the fittings. Adjoining the SRB attach fittings is a major ring frame. The loads are transferred from
3978-569: The SRM and taking the rest of the launch vehicle with it. At T+45 seconds, the Range Safety Officer sent the destruct command to ensure any remaining large pieces of the booster were broken up. An extensive recovery effort was launched, both to diagnose the cause of the accident and recover debris from the classified satellite. All of the debris from the Titan had impacted offshore, between three and five miles downrange, and at least 30% of
4080-707: The Solar System. The HGM-25A Titan I, built by the Martin Company , was the first version of the Titan family of rockets. It began as a backup ICBM project in case the SM-65 Atlas was delayed. It was a two-stage rocket operational from early 1962 to mid-1965 whose LR-87 booster engine was powered by RP-1 (kerosene) and liquid oxygen (LOX). The ground guidance for the Titan was the UNIVAC ATHENA computer , designed by Seymour Cray , based in
4182-506: The Standard Weight Tank (SWT) and was fabricated from 2219 aluminum alloy , a high-strength aluminum-copper alloy used for many aerospace applications. After STS-4 , several hundred pounds were eliminated by removing the anti-geyser line. This line paralleled the oxygen feed line, providing a circulation path for liquid oxygen. This reduces accumulation of gaseous oxygen in the feed line during prelaunch tanking (loading of
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4284-479: The Titan II guidance system. The main reason was to reduce the cost of maintenance by $ 72 million per year; the conversions were completed in 1981. Liquid oxygen is dangerous to use in an enclosed space, such as a missile silo , and cannot be stored for long periods in the booster oxidizer tank. Several Atlas and Titan I rockets exploded and destroyed their silos, although without loss of life. The Martin Company
4386-490: The Titan III family and was similar to the Titan 34D. While the launcher family had an extremely good reliability record in its first two decades, this changed in the 1980s with the loss of a Titan 34D in 1985 followed by the disastrous explosion of another in 1986 due to a SRM failure. Due to this, the Titan IV-B vehicle was intended to use the new composite-casing Upgraded Solid Rocket Motors. Due to development problems
4488-761: The Titan IIIA, eventually followed by the Titan IV-A and IV-B. By the mid-1980s the United States government worried that the Space Shuttle, designed to launch all American payloads and replace all unmanned rockets, would not be reliable enough for military and classified missions. In 1984 Under Secretary of the Air Force and Director of the National Reconnaissance Office (NRO) Pete Aldridge decided to purchase Complementary Expendable Launch Vehicles (CELV) for ten NRO payloads;
4590-574: The Titan program as "a nightmare". The 1998-99 schedule had called for four launches in less than 12 months. The first of these was Titan K-25 which successfully orbited an Orion SIGNIT satellite on May 9, 1998. The second was the K-17 failure, and the third was the K-32 failure. After a delay caused by the investigation of the previous failure, the 9 April 1999 launch of K-32 carried a DSP early warning satellite . The IUS second stage failed to separate, leaving
4692-533: The USA-186 optical imaging satellite for the National Reconnaissance Office. External Tank The Space Shuttle external tank ( ET ) was the component of the Space Shuttle launch vehicle that contained the liquid hydrogen fuel and liquid oxygen oxidizer . During lift-off and ascent it supplied the fuel and oxidizer under pressure to the three RS-25 main engines in the orbiter . The ET
4794-666: The United States Department of Defense (DOD). Derived from the Titan 34D and originally proposed as a medium-lift expendable launch system for the US Air Force, who selected the Delta II instead. Development was continued as a commercial launch system, and the first rocket flew in 1990. The Commercial Titan III differed from the Titan 34D in that it had a stretched second stage, and a larger payload fairing to accommodate dual satellite payloads. The Titan IIIM
4896-612: The United States. The most famous use of the civilian Titan II was in the NASA Gemini program of crewed space capsules in the mid-1960s. Twelve Titan II GLVs were used to launch two U.S. uncrewed Gemini test launches and ten crewed capsules with two-person crews. All of the launches were successful. Starting in the late 1980s, some of the deactivated Titan IIs were converted into space launch vehicles to be used for launching U.S. Government payloads. Titan 23G rockets consisted of two stages burning liquid propellant . The first stage
4998-443: The aft attachment area, there were also umbilicals that carried fluids , gases , electrical signals and electrical power between the tank and the orbiter. Electrical signals and controls between the orbiter and the two solid rocket boosters were also routed through those umbilicals. Although the external tanks were always discarded, it may have been possible to re-use them in orbit. Plans for re-use ranged from incorporation into
5100-453: The aft surfaces prevents liquified air from pooling in the intertank. The middle cylinder of the oxygen tank, and the propellant lines, could withstand the expected depths of frost accumulation condensed from humidity, but the orbiter could not take the damage from ice breaking free. The thermal protection system weighs 4,823 lb (2,188 kg). Development of the ETs thermal protection system
5202-456: The booster was recovered from the sea floor. Debris continued to wash ashore for days afterward, and the salvage operation continued until October 15. The Air Force had pushed for a "launch on demand" program for DOD payloads, something that was almost impossible to pull off especially given the lengthy preparation and processing time needed for a Titan IV launch (at least 60 days). Shortly before retiring in 1994, General Chuck Horner referred to
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#17327867732375304-409: The decommissioned Titan II ICBMs were refurbished and used for Air Force space launch vehicles, with a perfect launch success record. For orbital launches, there were strong advantages to using higher-performance liquid hydrogen or RP-1 fueled vehicles with liquid oxygen ; the high cost of using hydrazine and nitrogen tetroxide, along with the special care that was needed due to their toxicity, were
5406-638: The delivered LH 2 . The baffle is located at the siphon outlet just above the aft dome of the LH 2 tank. This outlet transmits the liquid hydrogen from the tank through a 17 inches (430 mm) line to the left aft umbilical. The liquid hydrogen feed line flow rate is 465 lb/s (12,700 kg/min) with the main engines at 104% or a maximum flow of 47,365 US gal/min (2.9883 m /s). The ET thermal protection system consists primarily of spray-on foam insulation (SOFI), plus preformed foam pieces and premolded ablator materials. The system also includes
5508-691: The end of the shuttle era. The SLWT provided 50% of the performance increase required for the shuttle to reach the International Space Station . The reduction in weight allowed the Orbiter to carry more payload to the highly inclined orbit of the ISS . SLWT specifications LOX tank Intertank LH 2 tank The contractor for the external tank was Lockheed Martin (previously Martin Marietta ), New Orleans, Louisiana. The tank
5610-569: The engines before the oxidizer pumps cavitate (run dry). In addition, 1,100 lb (500 kg) of liquid hydrogen are loaded over and above that required by the 6:1 oxidizer–fuel engine mixture ratio. This assures that cutoff from the depletion sensors is fuel-rich; oxidizer-rich engine shutdowns can cause burning and severe erosion of engine components, potentially leading to loss of the vehicle and crew. Unexplained, erroneous readings from fuel depletion sensors have delayed several shuttle launch attempts, most notably STS-122 . On December 18, 2007,
5712-411: The extended time that the shuttle spent on the launch pad prior to launch. NASA engineer Farouk Huneidi told the agency that the paint did not actually protect the foam. Martin Marietta (now part of Lockheed Martin ) reduced weight by leaving the rust-colored spray-on insulation unpainted beginning with STS-3 , saving approximately 272 kg (600 lb ). The original ET is informally known as
5814-704: The final launch from Vandenberg AFB occurred on 19 October 2005. Lockheed Martin Space Systems built the Titan IVs near Denver, Colorado, under contract to the US government . Two Titan IV vehicles are currently on display at the National Museum of the United States Air Force in Dayton, Ohio and the Evergreen Aviation and Space Museum in McMinnville, Oregon . The Titan IV was developed to provide assured capability to launch Space Shuttle –class payloads for
5916-546: The first few Titan IV-B launches flew with the old-style UA1207 SRMs. In 1988–89, The Ralph M. Parsons Company designed and built a full-scale steel tower and deflector facility, which was used to test the Titan IV Solid Rocket Motor Upgrade (SRMU). The launch and the effect of the SRMU thrust force on the Titan IV vehicle were modeled. To evaluate the magnitude of the thrust force, the SRMU
6018-421: The fittings to the major ring frame which then distributes the tangential loads to the intertank skin. Two panels of the intertank skin, called the thrust panels, distribute the concentrated axial SRB thrust loads to the LOX and LH 2 tanks and to adjacent intertank skin panels. These adjacent panels are made up of six stringer-stiffened panels. The intertank also functions as a protective compartment for housing
6120-552: The flange for attaching the LH 2 tank to the intertank. The aft major ring receives orbiter-induced loads from the aft orbiter support struts and SRB-induced loads from the aft SRB support struts. The remaining three ring frames distribute orbiter thrust loads and LOX feedline support loads. Loads from the frames are then distributed through the barrel skin panels. The LH 2 tank has a volume of 53,488 cubic feet (1,514.6 m ) at 29.3 psi (202 kPa) and −423 °F (−252.8 °C) (cryogenic). The forward and aft domes have
6222-441: The hydrogen tank. Also, significant portions of the tank were milled differently so as to reduce thickness, and the weight of the ET's aft solid rocket booster attachments was reduced by using a stronger, yet lighter and less expensive titanium alloy. The Super Lightweight Tank (SLWT) was first flown in 1998 on STS-91 and was used for all subsequent missions with two exceptions ( STS-99 and STS-107 ). The SLWT had basically
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#17327867732376324-404: The instantaneous mass of the vehicle due to the usage of the propellants. Normally, main engine cutoff is based on a predetermined velocity; however, if any two of the fuel or oxidizer sensors sense a dry condition, the engines will be shut down. The locations of the liquid oxygen sensors allow the maximum amount of oxidizer to be consumed in the engines, while allowing sufficient time to shut down
6426-612: The internal disintegration of the Soviet Union . As a result of these events and improvements in technology, the unit cost of a Titan IV launch was very high. Additional expenses were generated by the ground operations and facilities for the Titan IV at Vandenberg Air Force Base for launching satellites into polar orbits. Titan IVs were also launched from the Cape Canaveral Air Force Station in Florida,
6528-489: The later cases due to hydrogen leaks at this connection. This requires complete draining of the tanks and removal of all hydrogen via helium gas purge, a 20-hour process, before technicians can inspect and repair problems. A cap mounted to the swing-arm on the fixed service structure covers the oxygen tank vent on top of the ET during the countdown and is retracted about two minutes before lift-off. The cap siphons off oxygen vapor that threatens to form large ice accumulations on
6630-430: The leading edge of Space Shuttle Columbia 's wing at a few hundred miles per hour. The impact is believed to have damaged one comparatively large reinforced carbon-carbon panel on the leading edge of the left wing, believed to be about the size of a basketball which then allowed super-heated gas to enter the wing superstructure several days later during re-entry. This resulted in the destruction of Columbia and
6732-405: The liquid hydrogen tank. One of the liquid oxygen tank umbilical valves is for liquid oxygen, the other for gaseous oxygen. The liquid hydrogen tank umbilical has two valves for liquid and one for gas. The intermediate-diameter liquid hydrogen umbilical is a recirculation umbilical used only during the liquid hydrogen chill-down sequence during prelaunch. As the ET is filled, excess gaseous hydrogen
6834-452: The loss of its crew. The report determined that the external fuel tank, ET-93, "had been constructed with BX-250", a closeout foam whose blowing agent was CFC-11 and not the newer HCFC 141b. In 2005, the problem of foam shed had not been fully cured; on STS-114 , additional cameras mounted on the tank recorded a piece of foam separated from one of its Protuberance Air Load (PAL) ramps, which are designed to prevent unsteady air flow underneath
6936-506: The most powerful uncrewed rocket available to the United States, with proportionally high manufacturing and operations expenses. By the time the Titan IV became operational, the requirements of the Department of Defense and the NRO for launching satellites had tapered off due to improvements in the longevity of reconnaissance satellites and the declining demand for reconnaissance that followed
7038-463: The name came from the government's expectation that the rockets would "complement" the shuttle. Later renamed Titan IV, the rocket would only carry three military payloads paired with Centaur stages and fly exclusively from LC-41 at Cape Canaveral. However, the Challenger accident in 1986 caused a renewed dependence on expendable launch systems , with the Titan IV program significantly expanded. At
7140-401: The operational instrumentation. The LH 2 tank is the bottom portion of the ET. The tank is constructed of four cylindrical barrel sections, a forward dome, and an aft dome. The barrel sections are joined together by five major ring frames. These ring frames receive and distribute loads. The forward dome-to-barrel frame distributes the loads applied through the intertank structure and is also
7242-408: The orbiter. The plates help maintain alignment among the umbilicals. Physical strength at the umbilical plates is provided by bolting corresponding umbilical plates together. When the orbiter GPCs command external tank separation, the bolts are severed by pyrotechnic devices. The ET has five propellant umbilical valves that interface with orbiter umbilicals: two for the liquid oxygen tank and three for
7344-481: The payload in a useless orbit. Investigation into this failure found that wiring harnesses in the IUS had been wrapped too tightly with electrical tape so that a plug failed to disconnect properly and prevented the two IUS stages from separating. The fourth launch was K-26 on April 30, 1999, carrying a Milstar communications satellite. During the Centaur coast phase flight, the roll control thrusters fired open-loop until
7446-410: The problem was being attended to at around 3 a.m., leaking rocket fuel ignited and blew the 8,000 lb (3,630 kg) nuclear warhead out of the silo. It landed harmlessly several hundred feet away. There was one fatality and 21 were injured, all from the emergency response team from Little Rock AFB . The explosion blew the 740-ton launch tube cover 200 ft (60 m) into the air and left
7548-434: The propellant block. However, most of CSD's qualified personnel had left the program by this point and so the repair crew in question did not know the proper procedure. After replacement, they neglected to seal the area where the cut in the propellant block had been made. Post repair X-rays were enough for CC personnel to disqualify the SRMs from flight, but the SRMs were then shipped to Vandenberg and approved anyway. The result
7650-549: The same design as the LWT except that it used an aluminium-lithium alloy ( Al 2195 ) for a large part of the tank structure. This alloy provided a significant reduction in tank weight (about 7,000 pounds or 3,175 kg) over the LWT. Manufacture also included friction stir welding technology. Although all ETs produced after the introduction of the SLWT were of this configuration, one LWT remained in inventory to be used if requested until
7752-449: The same modified ellipsoidal shape. For the forward dome, mounting provisions are incorporated for the LH 2 vent valve, the LH 2 pressurization line fitting, and the electrical feed-through fitting. The aft dome has a manhole fitting for access to the LH 2 feedline screen and a support fitting for the LH 2 feedline. The LH 2 tank also has a vortex baffle to reduce swirl resulting from slosh and to prevent entrapment of gases in
7854-405: The spacecraft was sent into Saturn's atmosphere to burn up. While an improvement over the shuttle, the Titan IV was expensive and unreliable. By the 1990s, there were also growing safety concerns over its toxic propellants. The Evolved Expendable Launch Vehicle (EELV) program resulted in the development of the Atlas V , Delta IV , and Delta IV Heavy launch vehicles, which replaced Titan IV and
7956-431: The tank had not changed since 1993." The "new" foam containing HCFC 141b was first used on the aft dome portion of ET-82 during the flight of STS-79 in 1996. Use of HCFC 141b was expanded to the ETs area, or larger portions of the tank, starting with ET-88, which flew on STS-86 in 1997. During the lift-off of STS-107 on January 16, 2003, a piece of foam insulation detached from one of the tank's bipod ramps and struck
8058-646: The tank's cable trays and pressurization lines during ascent. The PAL ramps consist of manually sprayed layers of foam, and are more likely to become a source of debris. That piece of foam did not impact the orbiter. Reports published concurrent with the STS-114 mission suggest that excessive handling of the ET during modification and upgrade may have contributed to the foam loss on Discovery 's Return to Flight mission. However, three shuttle missions ( STS-121 , STS-115 , and STS-116 ) were later conducted, all with "acceptable" levels of foam loss. However, on STS-118
8160-579: The time of its introduction, the Titan IV was the largest and most capable expendable launch vehicle used by the USAF. The post-Challenger program added Titan IV versions with the Inertial Upper Stage (IUS) or no upper stages, increased the number of flights, and converted LC-40 at the Cape for Titan IV launches. As of 1991, almost forty total Titan IV launches were scheduled and a new, improved SRM ( solid rocket motor ) casing using lightweight composite materials
8262-596: The two Viking missions to place two orbiters around Mars and two instrumented landers on its surface. The Titan 34D featured Stage 1 and Stage 2 stretched with more powerful UA1206 solid motors. A variety of upper stages were available, including the Inertial Upper Stage , the Transfer Orbit Stage , and the Transtage . The Titan 34D made its maiden flight in the year of 1982 on the 30th of October with two DSCS defense communications satellites for
8364-429: The use of phenolic thermal insulators to preclude air liquefaction. Thermal isolators are required for liquid hydrogen tank attachments to preclude the liquefaction of air on exposed metal, and to reduce heat flow into the liquid hydrogen. While the warmer liquid oxygen results in fewer thermal requirements, the aluminum of the liquid oxygen tank forward areas require protection from aeroheating . Meanwhile, insulation on
8466-437: The weight of the ET to increase overall efficiency. The weight reduced from the ET resulted in an almost equal increase of the cargo-carrying capability of the Space Shuttle. The external tank's orange color, which would become iconic of the Space Shuttle program, is the color of the spray-on foam insulation. The first two tanks, used for STS-1 and STS-2 , were painted white to protect the tanks from ultraviolet light during
8568-617: The years), however SRB-equipped variants had a heat shield over them as protection from the SRB exhaust and the engines were modified for air-starting. The first guidance system for the Titan III used the AC Spark Plug company IMU (inertial measurement unit) and an IBM ASC-15 guidance computer from the Titan II. For the Titan III, the ASC-15 drum memory of the computer was lengthened to add 20 more usable tracks, which increased its memory capacity by 35%. The more-advanced Titan IIIC used
8670-474: Was Aerozine 50 , a 50/50 mix of hydrazine and UDMH, and the oxidizer was NTO. There were several accidents in Titan II silos resulting in loss of life and/or serious injuries. In August 1965, 53 construction workers were killed in fire in a missile silo northwest of Searcy, Arkansas . The fire started when hydraulic fluid used in the Titan II was ignited by a welding torch. The liquid fuel missiles were prone to developing leaks of their toxic propellants. At
8772-493: Was a near-repeat of 34D-9; a gap was left between the propellant and SRM casing and another burn-through occurred during launch. 1998 saw the failure of Titan K-17 with a Navy ELINT Mercury (satellite) from Cape Canaveral around 40 seconds into the flight. K-17 was several years old and the last Titan IV-A to be launched. The post-accident investigation showed that the booster had dozens of damaged or chafed wires and should never have been launched in that operating condition, but
8874-431: Was able to improve the design with the Titan II. The RP-1/LOX combination was replaced by a room-temperature fuel whose oxidizer did not require cryogenic storage. The same first-stage rocket engine was used with some modifications. The diameter of the second stage was increased to match the first stage. The Titan II's hypergolic fuel and oxidizer ignited on contact, but they were highly toxic and corrosive liquids. The fuel
8976-543: Was also the heaviest. It consisted of three major components: The ET was the "backbone" of the shuttle during launch, providing structural support for attachment with the Space Shuttle Solid Rocket Boosters (SRBs) and orbiter. The tank was connected to each SRB at one forward attachment point (using a crossbeam through the intertank) and one aft bracket, and it was connected to the orbiter at one forward attachment bipod and two aft bipods. In
9078-434: Was connected to the steel tower through load measurement systems and launched in-place. It was the first full-scale test conducted to simulate the effects of the SRMU on the Titan IV vehicle. In the early 1980s, General Dynamics developed a plan to assemble a lunar landing spacecraft in-orbit under the name Early Lunar Access . A Space Shuttle would lift a lunar lander into orbit and then a Titan IV rocket would launch with
9180-637: Was intended to launch the Manned Orbiting Laboratory and other payloads. Development was cancelled in 1969. The projected UA1207 solid booster rockets were eventually used on the Titan IV . The Titan IV was an extended length Titan III with solid rocket boosters on its sides. The Titan IV could be launched with a Centaur upper stage, the USAF Inertial Upper Stage (IUS), or no upper stage at all. This rocket
9282-645: Was introduced. In 1990, the Titan IV Selected Acquisition Report estimated the total cost for the acquisition of 65 Titan IV vehicles over a period of 16 years to US$ 18.3 billion (inflation-adjusted US$ 42.7 billion in 2024). In October 1997, a Titan IV-B rocket launched Cassini–Huygens , a pair of probes sent to Saturn . It was the only use of a Titan IV for a non-Department of Defense launch. Huygens landed on Titan on January 14, 2005. Cassini remained in orbit around Saturn. The Cassini Mission ended on September 15, 2017, when
9384-614: Was jettisoned just over 10 seconds after main engine cut-off (MECO) and it re-entered the Earth's atmosphere. Unlike the Solid Rocket Boosters , external tanks were not re-used. They broke up before impact in the Indian Ocean (or Pacific Ocean in the case of direct-insertion launch trajectories), away from shipping lanes and were not recovered. The ET was the largest element of the Space Shuttle, and when loaded, it
9486-568: Was manufactured at the Michoud Assembly Facility , New Orleans , and was transported to Kennedy Space Center by barge . The ET has three primary structures: an LOX tank, an intertank, and an LH 2 tank. Both tanks are constructed of aluminium alloy skins with support or stability frames as required. The intertank aluminium structure utilizes skin stringers with stabilizing frames. The primary aluminium materials used for all three structures are 2195 and 2090 alloys. AL 2195
9588-422: Was more formally known as Program 624A ( SSLS ), Standard Space Launch System , Standardized Space Launch System , Standardized Space Launching System or Standard Space Launching System (all abbreviated SSLS ). The Titan III core was similar to the Titan II, but had a few differences. These included: The Titan III family used the same basic LR-87 engines as Titan II (with performance enhancements over
9690-523: Was powered by one Aerojet LR87 engine with two combustion chambers and nozzles, and the second stage was propelled by an LR91 . On some flights, the spacecraft included a kick motor, usually the Star-37XFP-ISS ; however, the Star-37S was also used. Thirteen were launched from Space Launch Complex 4W (SLC-4W) at Vandenberg Air Force Base starting in 1988. The final such vehicle launched
9792-433: Was problematic. Anomalies in foam application were so frequent that they were treated as variances, not safety incidents. NASA had difficulty preventing fragments of foam from detaching during flight for the entire history of the program: In 1995, chlorofluorocarbon-11 (CFC-11) began to be withdrawn from large-area, machine-sprayed foams in compliance with an Environmental Protection Agency ban on CFCs under section 610 of
9894-551: Was the Vandenberg Air Force Base version of the Titan IIIC, without a Transtage, that was used to place members of the Key Hole series of reconnaissance satellites into polar low Earth orbits . The Titan IIIE, with a high- specific-impulse Centaur upper stage, was used to launch several scientific spacecraft, including both of NASA's two Voyager space probes to Jupiter, Saturn and beyond, and both of
9996-407: Was the cause of the accident. After Titan 34D-9, extensive measures had been put in place to ensure proper SRM operating condition, including X-raying the motor segments during prelaunch checks. The SRMs that went onto K-11 had originally been shipped to Cape Canaveral, where X-rays revealed anomalies in the solid propellant mixture in one segment. The defective area was removed by a pie-shaped cut in
10098-437: Was the largest missile developed for the USAF at that time. The Titan II had newly developed engines which used Aerozine 50 and nitrogen tetroxide as fuel and oxidizer in a self-igniting, hypergolic propellant combination, allowing the Titan II to be stored underground ready to launch. Titan II was the first Titan vehicle to be used as a space launcher. Development of the space launch only Titan III began in 1964, resulting in
10200-519: Was the nation's first two-stage ICBM and complemented the Atlas ICBM as the second underground, vertically stored, silo-based ICBM. Both stages of the Titan I used liquid oxygen and RP-1 as propellants. A subsequent version of the Titan family, the Titan II , was a two-stage evolution of the Titan I, but was much more powerful and used different propellants. Designated as LGM-25C, the Titan II
10302-543: Was used almost exclusively to launch US military or Central Intelligence Agency payloads. However, it was also used for a purely scientific purpose to launch the NASA–ESA Cassini / Huygens space probe to Saturn in 1997. The primary intelligence agency that needed the Titan IV's launch capabilities was the National Reconnaissance Office (NRO). When it was being produced, the Titan IV was
10404-493: Was used for the majority of the Shuttle flights, and was last used during the launch of the ill-fated STS-107 mission. Although tanks vary slightly in weight, each weighed approximately 66,000 pounds (30,000 kg) inert. The weight reduction from the SWT was accomplished by eliminating portions of stringers (structural stiffeners running the length of the hydrogen tank), using fewer stiffener rings and by modifying major frames in
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