As might be expected, crew training and planning for a particular Space Shuttle mission are closely intertwined. The key elements of mission planning outline specific crew activities and essential flight support functions. The effort, like astronaut training, is directed by NASA's Johnson Space Center (JSC), Houston, Mission Operations Directorate (MOD). The degree of thoroughness of this planning probably can best be described as mind boggling. Since crew activity planning is the analysis and development of when and what activities are to be performed on a specific mission, the end result is a minute-by-minute timeline of each crewmember's activities.
A second aspect of mission planning is operations support planning. This is a detailed analysis of flight requirements and ground flight control operations essential to support a proposed mission. One part of this activity includes reviewing flight controller documentation and up-dating it when flight requirements call for up-date. This comprehensive review includes numerous basic Space Shuttle operations documents including:
¥ Space Transportation System Flight Rules
¥ Console Handbooks
¥ Command Plans
¥ Communications and Data Plans
¥ Mission Control and Tracking Network Support Plans
¥ Systems Operating Procedures
¥ Operations and Maintenance Instructions
¥ Flight Control Operations Handbooks
¥ Flight Software Documentation
Other important flight planning work is done by the MOD's Flight Design and Dynamics Division. Here, a mission's flight profile is developed, and flight analysis and the design and production of mission planning products is accomplished. Briefly, some of the major activities of this organization include:
¥ Assessment of a specific flight with particular emphasis on ascent performance.
¥ Flight design analysis leading development of flight design ground rules and constraints
¥ Commit-to-flight certification for flight readiness.
¥ Trajectory, navigation and guidance design, as well as performance analyses for ascent, orbit shaping, separation and collision avoidance, payload deployment, rendezvous, proximity operations and descent and landing operations.
¥ Development of checklists for ascent, rendezvous proximity operations and crew descent procedures.
¥ Development of flight programs for the Shuttle Portable OnBoard Computer (SPOC) for flight.
¥ Preparation of operating procedures, console handbooks, flight mission rules and other operational documentation to support flight operations.
Finally, there is the actual Shuttle mission, spacecraft deployment or experiment activity, ending in data analysis and distribution.
The two most important phases of payload integration planning include the development of the formal agreements between the user and NASA and the implementation of these agreements. Other considerations involved in payload integration planning include safety reviews of all phases of the mission, such as payload design, flight operations, ground support equipment design and overall ground operations. These preparations are reviewed by a NASA safety panel working with the user to assess the complexity, technical maturity and hazard potential of a specific payload and mission plan.
The integration procedures for a Shuttle payload begin with a preliminary flight assessment and continue through the requirements development phase with each user. After the preliminary launch and services agreements are signed, a series of cargo compatibility assessments are made. This information is presented to the user and NASA management at a formal meeting called the Cargo Integration Review.
Meanwhile, when to schedule a user's payload for flight is the responsibility of the Flight Assignment Working Group (FAWG) at JSC. The user's requirements are assessed and other payloads, with compatible orbital requirements and configurations, are placed on the launch manifest together, if space and weight constraints permit. This preliminary flight assessment manifest then is reviewed at KSC to permit development of a ground processing flow schedule to establish a realistic launch date for
These purely administrative activities continue after the preliminary flight assessment schedule is published. NASA then does a preliminary cargo engineering analysis to confirm that the proposed cargo elements are compatible with each other and the capabilities of the Shuttle system itself. These important analyses are based on information contained in the Payload Integration Plan (PIP) and its annexes. Cargo engineering and preliminary flight analyses must be ready early enough to permit completion of detailed hardware requirements for the mission. All of this information is evaluated at a Cargo Integration Review meeting. If it is agreed that all requirements have been met, final flight operations plans are then prepared.
Flight operations planning includes final flight design, any modifications needed in the Mission Control Center (MCC) or the user's Payload Operations Control Center (POCC), and detailed crew training programs. These items are then formally reviewed by the Flight Operations Review Board, still another level in the comprehensive process of getting ready for a mission.
Finally, the payloads or cargo for a specific mission undergo their final checkouts before launch. The user or owner of the payload is responsible for verifying the payload compatibility and functional interfaces before payload processing procedures start. NASA, on the other hand, is responsible for verifying the compatibility of the integrated cargo.
Just before a payload is installed in the Shuttle's payload bay, a Payload Readiness Review is held at KSC. This review, one of the last in a long process, assesses the readiness of the the Shuttle and the payload for what are called the "payload on-line integration activities."
The last major cargo/Shuttle review prior to launch is the Flight Readiness Review which verifies that all integration operations have been completed satisfactorily and gives final certification that the flight elements are ready to go.
The allowable cargo weight for a Space Shuttle flight is a function of the various operational activities and the type of mission being conducted. The allowable cargo weight is constrained by either ascent performance or landing weight limits if a payload such as Spacelab is returned to Earth. It also may be affected by such other factors such as orbital altitude, orbital inclination, mission duration and rendezvous requirements.
Payload control weight is another term used for Shuttle cargo allowances. It includes the weight of the payload itself, plus any airborne support equipment and payload-unique hardware, as well as the weight of payload specialists, their personal equipment and provisions up to a limit of 490 pounds per individual. Payload weight control is an important item in the PIP, and increases only can be made by a specific agreement amending the original PIP.
Cargo weight is defined as the payload control weight plus the weight of the attached hardware used to secure the payload to the orbiter. Allowable cargo weight is determined by altitude and orbital inclination. For example, on a standard inclination of 28.45 degrees, maximum cargo weight capability in a circular orbit at an altitude of 100 nautical miles is about 55,000 lb. This capability decreases with altitude and falls to about 40,000 lb. in a 300-mile circular orbit. At the higher inclination of 57 degrees (also a standard inclination), cargo weight capability is 40,000 lb. in a 100-mile circular orbit. This decreases to slightly over 20,000 lb. in a 320-mile-high orbit. These weights are those for a nominal ascent for what is described as a "simple, short duration, satellite deploy mission."
The allowable cargo weight also is constrained by landing weight limits. For spacecraft deployment missions in which the payload or payloads remain in orbit, the orbiter abort landing weight limit is a constraining factor. Although nominal-end-of mission landing weight applies to all flights, it is only a constraint consideration if a major portion of the payload is returned to Earth.
For orbiters Discovery (OV-103) and Atlantis (OV-104) and the unnamed OV-105 under construction, the abort landing weight constraints cannot exceed 50,500 lb. of allowable cargo on the so-called simple satellite deployment missions. For longer duration flights with attached payloads, the allowable cargo weight for end-of-mission or abort situations is limited to 25,000 lb. For Columbia (OV-102), however, these allowable cargo weights are reduced by 8,400 lb.
In November 1987, NASA announced that the allowable end-of- mission total landing weight for Space Shuttle orbiters had been increased from the earlier limit of 211,000 lb. to 230,000 lb. The higher limit was attributed to an on-going structural analysis and additional review of forces encountered by the orbiter during maneuvers just before touch down. This new capability increases the performance capability between lift capacity to orbit and the allowable return weight during reentry and landing. Thus, the Shuttle will be able to carry a cumulative weight in excess of 100,000 lb. of additional cargo through 1993. This additional capability is expected to be an important factor in delivering materials for construction of the Space Station. Moreover, the new allowable landing weights are expected to aid in relieving the payload backlog which resulted from the STS 51-L Challenger accident.
The Space Shuttle has three basic payload accommodation categories. These are dedicated, standard and middeck accommodations.
Standard payloads -- usually geosynchronous communications satellites -- are the primary type of cargo carried by the Shuttle. Normally, accommodations are available in the payload bay for up to four standard payloads per flight. Space is allocated based on specific requirements of a payload and load factors.
Middeck payloads-small, usually self-contained packages - are stored in compartments on the middeck. These are often manufacturing-in-space or small life sciences experiments.
For standard-type payloads, the payload bay has structural support points along its length for payload mounting fixtures provided by the user. Payloads can be supported by attach fittings at 248 locations along both sides of the payload bay. There are 104 attach points along the payload bay floor at the orbiter's keel centerline. For deployable payloads, active fittings are used. The attachment provisions are adaptable to various payload designs and provide load reaction and strain isolation between the orbiter and the payload itself. The most common attachment devices are known as the three- and five-point types.
The avionics services for standard payloads -- power, command and data services are provided through what is called a standard mixed cargo harness (SMCH). The harness consists of cables which are routed to a payload through wire trays located on either side of the payload bay. Cables on the right or starboard side of the payload bay area contain the electrical interfaces -- plugs -- while those on the left or port side provide signal and control interfaces. It is possible to access the SMCH from the cable trays at almost any location along the payload bay sides.
Electrical power from the orbiter to the payloads is distributed through the standard interface panel. A nominal of 28 volt direct current is available during ground operations, ascent, orbital operations, and descent. During prelaunch operations up to 250 watts of power is available to perform payload checkouts. During ascent or descent, the amount of continuous power available to payloads is 250 watts maximum. Higher power levels are available for brief periods to facilitate payload checkout or to accommodate active operations, especially payload deployments.
A variety of command services are available for payloads either from the orbiter itself, the MCC or from the POCC. Ground-originated commands to payloads are relayed through the orbiter's communications system. If necessary, the flight crew can send payload commands, through the standard switch panel or by placing command instructions through the keyboard into the orbiter's avionics system.
Monitoring and processing payload data can be done on board the orbiter, through the MCC or the user POCC. Payload telemetry is funnelled through the orbiter's communications to the MCC or the POCC. Eventually, the operational Tracking and Data Relay Satellite System (TDRSS) -- the space network -- will make payload data available for practically an entire orbit which is not the case with ground tracking stations.
The standard payload data recording capability on board the orbiter includes three parallel tape recording channels, one analog and two digital. Ten-minute segments of recording time are available during ascent, payload deployment and descent.
Timing services for standard payloads include one mission elapsed time (MET) signal and two Greenwich Mean Time (GMT) signals in what is known as the interrange instrumentation Group- B (IRIG-B) modified code format.
The orbiter's thermal accommodations for payloads provide nominal thermal environments which meet the requirements of practically all standard payloads. During prelaunch and postlanding operations, the payload bay "purge" provides limited thermal conditioning. The actual thermal environment depends on a number of factors including the thermal interactions between the orbiter and the payloads. For mixed cargo payloads, the payload design must be compatible with standard purge and attitude requirements.
The pointing capability of the orbiter at an inertial attitude is a remarkable plus or minus one degree. For dedicated flights -- those with a single payload -- the selected attitude can be maintained as long as the thermal constraints of the orbiter itself are not exceeded. For mixed standard cargos, a given attitude cannot be maintained longer than the standard mixed cargo thermal criteria allow, unless specified in the payload integration plan.
Small payloads mounted in the payload bay do not need the full range of accommodations required for large, standard payloads. Small payloads can be mounted in either a side-mounted or an across-the-bay configuration. In the side-mounted method, the payload is mounted on a side wall payload carrier. This only can be done on the right or starboard side of the payload bay. In the across-the-bay configuration, the payload is mounted on a structure provided by the payload user which is attached to an avionics outlet similar to the ones used by standard payloads.
The maximum electrical power available for small payloads, during pre-launch checkout and orbital operations, is l,400 watts or a nominal 28 volts of direct current. During high power use by other payloads on board -- especially during deployment of standard payloads -- electrical power for small payloads may be cut to 300 watts.
Small payloads can be commanded by limited discrete commands from the flight crew or by serial digital commands originating from user's POCC and relayed to the payload through the MCC. Command services are available on a time-shared basis with the orbiter and other payload operations.
Data processing and display is done on the orbiter and at the user's POCC. Telemetry data is made available at the user's POCC on a time-shared basis with other on board payloads.
The critically-important timing information for small payloads is available from one MET signal and through the IRIG-B in modified code format, similar to that available to standard payloads.
Small payload thermal conditions are those experienced in payload bay thermal environments. NASA recommends that small payloads be designed with a self-contained thermal control system and that the thermal attitude capability be essentially equivalent to that of the orbiter.
In addition to the payload bay area, the Space Shuttle can accommodate small payloads in the middeck of the crew compartment. This location is ideal for payloads that require a pressurized crew cabin environment or must be operated directly by the crew. Another advantage of the middeck is that small payloads can be stowed on board shortly before launch and they can be removed quickly and easily after landing.
Middeck payloads are stored in small, 2-cubic-foot lockers. Each locker can hold up to 60 lb. of cargo. Moreover, trays with dividers can be installed to divide each locker into 16 compartments. Payload hardware that replaces one or more lockers -- using standard locker mounting locations -- also can be accommodated.
Electrical power available for middeck payloads during on- orbit operations ranges up to 5 amps of nominal 28-volt direct current. Continuous power used by a middeck payload is limited to 115 watts for no more than 8 hours or no more than 200 watts peak for periods of 10 seconds or less. For middeck payloads that require electrical power, standard cables are available for routing power from utility outlets to the payload. The heat load from middeck experiments is dissipated into the crew compartment.
Command and monitoring of middeck payloads is limited to internal controls, displays and data collection capabilities built into the payloads. Remote Manipulator System
The remote manipulator system (RMS) is the Canadian-built mechanical arm component of the payload deployment and retrieval system (PDRS). It is used for payload deployment, retrieval, special handling operations and orbiter servicing activities. The arm is 50 ft., 3 in. long and is mounted along the left or port side of the payload bay, outside a 15-ft. diameter envelope reserved for cargo. The RMS has proven to be a versatile and invaluable instrument for Shuttle operations.
To support payload missions, members of the flight crew can provide unique ancillary services in three specific areas. These are extravehicular activity (EVA), intravehicular activity (IVA) and in-flight maintenance (IFM).
Extravehicular activity refers to those activities during which crew members don pressurized space suits and life support systems, leave the orbiter cabin and perform various payload- related activities in the vacuum of space, frequently outside the payload bay -- becoming, in effect, human satellites. The requirements for performing EVAs are spelled out in the PIP.
IVA includes all activities during which crew members dressed in space suits and using life support systems perform hands-on operations "internal to a customer-supplied crew module." The requirements for performing IVA also are specified in the PIP. (IVAs performed in the Spacelab do not require crew members to dress in space suits with life support systems.)
Finally, IFM is any off-normal, on-orbit maintenance or repair action conducted to repair a malfunctioning payload. In- flight maintenance procedures, for planned payload maintenance or repair, are developed before a flight and often involve EVA.
The first group of astronauts -- known as the Mercury seven -- was selected by NASA in 1959. Since then ll other groups of astronaut candidates have been selected. Through the end of 1987, there have been 172 graduates of the astronaut program.
With the advent of the Space Shuttle, the first astronaut candidates for that program -- 35 in all -- were selected in January 1978. They began training at JSC the following June. The group consisted of 20 mission specialists and 15 pilots and included six women and four members of minority groups. They completed their 1-year basic training program in August 1979.
Since then, four additional groups of pilots and mission specialists were selected to become members of the astronaut corps. They included 19 selected in July 1980, 17 in July 1984, 13 in August 1985 and 15 in June 1987. In addition, a new crew category, the payload specialist, was added to meet expanded capabilities of the Space Shuttle program.
The astronaut candidate program is an ongoing and NASA accepts applications from qualified individuals -- from both civilian and military walks of life -- on a continuing basis, selecting candidates as needed for the rigorous, 1-year training program directed by JSC. Upon completing the course, successful candidates become regular members of the astronaut corps. Usually they are eligible for a flight assignment about 1 year after completing the basic training program.
Early in the U.S. manned space program, jet aircraft and engineering training were prerequisites for selection as an astronaut. Today, scientific education and experience are equally important prerequisites in selecting both pilots and mission specialists.
Pilot astronauts play a key role in Shuttle flights, serving as either commanders or pilots. During flights, commanders are responsible for the vehicle, the crew, mission success and safety -- duties analogous to those of the captain of a ship. Shuttle commanders are assisted by pilot astronauts who are second in command and whose primary responsibilities involve controlling and operating the Shuttle. During flights, commanders and pilots usually assist in spacecraft deployment and retrieval operations using the RMS arm or other payload-unique equipment on board the Shuttle.
To be selected as a pilot astronaut candidate an applicant must meet a number of basic qualification requirements. A bachelor's degree in engineering, biological science, physical science or mathematics is required. A graduate degree is desired, although not essential. The applicant must have had at least l,000 hours flying time in jet aircraft. Experience as a test pilot is desirable, but not required. All applicants -- pilots and missions specialists -- must be citizens of the United States.
Physically, an applicant must pass a strict physical examination and have a distant visual acuity no greater than 20/50 uncorrected, correctable to 20/20. Blood pressure, while sitting, must be no greater than 140 over 90. An applicant also must also be between 64" to 76" tall.
Mission specialist astronauts, working closely with the commander and pilot, are responsible for coordinating on board operations involving crew activity planning, use and monitoring of the Shuttle's consumables (fuel, water, food, etc.), and conducting experiment and payload activities. They are required to have a detailed knowledge of Shuttle systems and the "operational characteristics, mission requirements and objectives and supporting systems for each of the experiments to be conducted on the assigned missions." Mission specialists perform on-board experiments, spacewalks (called extravehicular activity (EVA) and payload handling functions involving the RMS arm.
The basic physical qualifications for selection as a mission specialist astronaut are the same as those for pilots, except that uncorrected visual acuity can be as high as 20/100, correctable to 20/20. A candidate's height can range from 60" to 76".
Academically, applicants must have a bachelor's degree in engineering, biological science, physical science or mathematics plus at least 3 years of related and progressively responsible professional experience. An advanced degree can be substituted for part or all of the experience requirement, 1 year for a master's degree and 3 years for a doctoral degree.
This newest category of Shuttle crew member, the payload specialist, is a professional in the physical or life sciences or a technician skilled in operating Shuttle-unique equipment. Selection of a payload specialist for a particular mission is made by the payload sponsor or customer. For NASA-sponsored spacecraft or experiments requiring a payload specialist, the specialist is nominated by an investigator working group and approved by NASA.
Payload specialists for major non-NASA payloads or experiments are selected by the sponsoring organization. payload specialists do not have to be U.S. citizens. However, they must meet strict NASA health and physical fitness standards.
In addition to intensive training for a specific mission assignment at a company plant, a university or government agency, the payload specialist also must take a comprehensive flight training course to become familiar with Shuttle systems, payload support equipment, crew operations, housekeeping techniques and emergency procedures. This training is conducted at JSC and other locations, as required. Payload specialist training may begin as much as 2 years before a flight.
Since the STS 51-L accident, the payload specialist program has been under review by NASA and a decision is pending on whether to continue with this special crew member category.
Astronaut training is highly specialized and requires the efforts of literally hundreds of persons and numerous facilities. It is conducted under the auspices of JSC's Mission Operations Directorate.
As manned space flight programs have become more sophisticated over the years so too has the complex and length training process needed to meet the demands of operating the Space Shuttle.
Initial training for new candidates consists of a series of short courses in aircraft safety, including instruction in ejection, parachute and survival to prepare them in the event their aircraft is disabled and they have to eject or make an emergency landing. Pilot and mission specialist astronauts are trained to fly T-38 high-performance jet aircraft, which are based at Ellington Field near JSC.
Flying these aircraft, pilot astronauts are able to maintain their flying skills and mission specialists are able to become familiar with high-performance jets.
In the formal academic areas, the novice astronauts are given a full range of basic science and technical courses, including mathematics, Earth resources, meteorology, guidance and navigation, astronomy, physics and computer sciences.
Basic knowledge of the Shuttle system, including payloads, is obtained through lectures, briefings, text books and flight operations manuals. Mockups of the orbiter flight and middecks, as well as the mid-body, including a full-scale payload bay, train future crew members in orbiter habitability, routine housekeeping and maintenance, waste management and stowage, television operations and extravehicular activities.
As training progresses, the student astronauts gain one-on- one experience in the single systems trainers (SST) located in Building 4 at JSC. The SSTs contain computer data bases with software allowing students to interact with controls and displays like those of a Shuttle crew station. Here they can develop work procedures and react to malfunction situations in a Shuttle-like environment.
Learning to function in a weightless or environment is simulated in aircraft and in an enormous "neutral buoyancy" water tank at JSC.
Aircraft weightless training is conducted in a modified KC- 135 four-engine jet transport. Flying a parabolic course, the aircraft is able to create up to 30 seconds of weightlessness when flying a parabolic maneuver. During this rather brief period of time, astronauts can practice eating and drinking as well as use various kinds of Shuttle-type equipment. Training sessions in the KC-135 normally last from 1 to 2 hours, providing an exciting prelude to the sustained weightless experience of space flight.
Longer periods of weightlessness are possible in the neutral buoyancy tank, officially called the Weightless Environment Training Facility (WETF), in Building 29 at JSC. Here, a full- scale mockup of the orbiter payload bay and airlock can be placed in the 25-foot-deep water tank permitting extended training periods for practicing EVA -- space walks -- by trainees wearing pressurized EVA suits.
The facility also is an essential tool for the design, testing and development of spacecraft and EVA crew equipment. In addition, it makes possible evaluation of payload bay body restraints and handholds, permits development of various crew procedures and, perhaps most importantly, helps determine an astronaut's EVA capabilities and workload limitations.
Other major operations training facilities at JSC include the Computer-Aided Instructional Trainer (CAIT) in Building 4, which fills the gap between textbook lessons and more complex trainers and simulators; the Crew Software Trainer (CST) used to demonstrate orbiter software capabilities before students go on to the SSTs; the Shuttle Mission Simulator (SMS) described earlier; the Orbiter Crew Compartment Trainer in Building 9A, used to train crew members for most of their on-orbit duties; as well as engineering mockups of orbiter work stations, the Spacelab and the remote manipulator system.
Most of these training facilities also are used by regular members of the astronaut corps to help them maintain proficiency in their areas of specialization.
Since the orbiter lands on a runway much like a high- performance aircraft, pilot astronauts use conventional and modified aircraft to simulate actual landings. In addition to the T-38 trainers, the four-engine KC-135 provides experience in handling large, heavy aircraft. Pilot astronauts also use a modified Grumman Gulfstream II, known as the Shuttle Training Aircraft (STA), which is configured to simulate the handling characteristics of the orbiter. It is used extensively for landing practice, particularly at the Ames Dryden Flight Research Facility (DFRF) in California and at KSC's Shuttle Landing Facility.
Advanced training follows the 1-year basic training course for new astronauts. The Mission Operations Directorate's Flight and Systems Branches at JSC direct this advanced training which includes 16 different course curricula covering all Shuttle-related crew training requirements. The courses range from guidance, navigation and control systems to payload deployment and retrieval systems. This advanced training encompasses two specific types of instruction. These are system-related and phase-related training.
The bulk of system-related training is carried out in the various low and medium fidelity trainers and computer-aided instructional trainers at JSC. This approach permits self-paced, interactive programmed instruction for both initial and refresher systems training. Systems instructors provide one-on-one training by controlling simulator software, setting up staged malfunctions and letting the trainee solve them.
System training is designed to provide instruction in orbiter systems. It is not related to a specific mission or its cargo. It is designed to familiarize the trainee with a feel for what it's like to work and live in space. Generally, systems training is completed before an astronaut is assigned to a mission.
As its name implies, the second type of advanced training, phase-related training, concentrates on the specific skills an astronaut needs to perform successfully in space. This training is conducted in the SMS, which is the primary facility for training astronauts in all phases of a mission from liftoff to landing.
Phase-related training continues after a crew is assigned to a specific mission, normally about 7 months to 1 year before the scheduled launch date.
From this point on, crew training becomes more structured and is directed by a training management team. At any one time, there are nine structured Shuttle Mission Simulator teams operating at JSC. Each is assigned to a specific Shuttle flight. These specialized teams are responsible for directing the remaining advanced training needed for a specific flight. This includes what is described as "stand-alone training and flight-specific integrated and joint integrated training." It involves carefully developed scripts and scenarios for the mission. This intensive training is designed to permit the crew to operate as a closely integrated team, performing normal flight operations according to a flight timeline.
At about 10 weeks before a scheduled launch, the crew begins what are called "flight-specific integrated simulations, designed to provide a dynamic testing ground for mission rules and flight procedures." Just as during a real mission, the crew works at designated stations interacting with the flight control team who man their positions in the operationally-configured MCC.
These final pre-launch segments of training are called integrated and joint integrated simulations and normally include the payload users' operations control centers. Everything from EVA operations to interaction with the tracking networks can be simulated during these training sessions.
The integrated simulations are directed by a simulation supervisor, who is referred to as the "sim sup," assisted by a team of flight-specific instructors who direct and observe the simulations, evaluate crew and controller responses to malfunctions and other flight-unique situations. This final intensive training joint crew/flight controller effort is carried out in parallel with the complex and extensive activity called mission planning.
The Shuttle Mission Simulator (SMS) is the primary system for training Space Shuttle crews. Located in Building 5 at JSC, it is described as the only high-fidelity simulator capable of training crews for all phases of a mission beginning at T-minus 30 minutes, including such simulated events as launch, ascent, abort, orbit, rendezvous, docking, payload handling, undocking, deorbit, entry, approach, landing and rollout.
The unique simulator system can duplicate main engine and solid rocket booster performance, external tank and support equipment and interface with the MCC. The SMS construction was completed in 1977 at a cost of about $100 million. The SMS, is operated for NASA by the Link Flight Simulation Division of The Singer Co., Binghamton, N.Y.
Major components of the SMS are two orbiter cockpits, one called the motion-base crew station (MBCS) and the other the fixed-base crew station (FBCS). Each is equipped with the identical controls, displays and consoles, of an actual orbiter. Although in many ways more complex, the crew station simulators are similar to the trainers used for commercial airline pilots.
The MBCS is configured for Shuttle commander and pilot positions. It operates with motion cues supplied by a modified 6-degree-of-freedom motion system providing motion simulation for all phases of a flight from launch to descent and landing. A special tilt frame provides a 90-degree upward tilt that simulates acceleration of liftoff and ascent.
The FBCS is configured for the commander, pilot, mission specialist and payload operations crew positions. While it does not simulate motion, it does have navigation, rendezvous, remote manipulator and payload accommodation systems configured to simulate specific payload activities planned for future missions. The FBCS is located on an elevated platform and it is entered through a hatch like the one on the orbiter. During long-duration mission simulations water and food are provided in the FBCS.
Visual simulations for the two training stations are provided by four independent digital image generation (DIG) systems. The DIG can display scenes for every phase of a Shuttle mission from pre-launch pad views to landing and rollout on the runway. The views are displayed in color in the six orbiter forward windows of the two stations, while the overhead and two aft widows have a green hue. The Earth, sun, moon and stars are included in these visual scenes. A closed circuit television display provides proper spatial ordering of moving objects for aft window and closed circuit TV fields of view. The closed circuit TV also permits viewing the payload through fixed cameras or through cameras mounted on remote manipulator arms. This is important for payload deployment and retrieval training.
Computer-generated sound simulations come from hidden loudspeakers which duplicate those experienced during an actual flight, including the onboard pumps, blowers, mechanical valves, aerodynamic vibrations, thruster firings, pyrotechnic explosions, gear deployment and runway touchdown.
SMS instructors at consoles act as devil's advocates in devising scenarios of systems failures or other circumstances to which astronaut crews and flight control teams must react. There are about 6,800 malfunction simulations that can be activated from the instructor consoles. Both SMS trainers can be used separately or in integrated simulations linked to flight control teams in the MCC.
Two independent computer facilities comprise the SMS computer system. Each has a Univac 110/40 host computer containing a majority of the mathematical modes used for simulated flights. Fourteen microcomputers perform data collection and transfer as well as other functions. There are two simulation interface devices (called SIDs) that communicate with flight computer systems. The flight computer systems, like those actually on the Shuttle, are five IBM AP 101s. Finally, four DIG computers and various input/output processors complete the basic SMS computer system.
The SMS can be interfaced with other simulators to duplicate various Shuttle missions. The European Space Agency's Spacelab Simulator (SLS), also in Building 5, is one of these.
The SMS design is modular which allows easy installation of update kits as well as specialized mission and payload simulation kits.
. Space Shuttle processing, checkout and countdown procedures are more automated and streamlined than those of earlier manned space flight programs thanks to the Launch Processing System (LPS). This unique system automatically controls and performs much of the Shuttle processing from the arrival of individual components and their integration, to launch pad operations and, ultimately, the launch itself.
The LPS consists of three basic subsystems: the Central Data Subsystem (CDS) located on the second floor of the Launch Control Center (LCC), the Checkout, Control and Monitor Subsystem (CCMS) located in in the firing rooms and the Record and Playback Subsystem (RPS).
The CDS consists of large-scale computers which store such vital data as test procedures, vehicle processing data, a master program library, historical data, pre- and post-test data analysis as well as other essential information. This information is automatically available to the smaller capacity computers of the CCMS.
Actual processing and launch of the Space Shuttle is controlled by the CCMS. These tasks are accomplished by using computer programs to monitor and record the pre-launch performance of all Shuttle electrical and mechanical systems. Command signals from the subsystem computer are sent to hundreds of components and test circuits. While a vehicle component is functioning, a sensor measures its performance and sends data back to the LPS. The data is compared against the checkout limits stored in the system's computer memory. Pre-determined measurements related to test requirements launch commit criteria and performance specifications are stored in the CCMS computers.
Finally, the RPS, mentioned above, records unprocessed Shuttle instrumentation data during test and launch countdowns. This data can be played back for post-test analysis when firing room engineers are troubleshooting Shuttle or LPS problems.
RPS consists of tape records, telemetry demultiplexing equipment, chart recorders and computers to provide data reduction capabilities.
After a Space Shuttle launch, the expended solid rocket boosters (SRB) are parachuted into the Atlantic Ocean off shore from the Complex 39 launch site. The boosters are retrieved by recovery vessels and towed back to facilities on the Cape Canaveral Air Force Station (CCAFS) where they are taken apart and cleaned.
The empty propellant-carrying segments are taken then to booster processing facilities at Complex 39 where they are inspected, packed and shipped by rail to the Morton-Thiokol manufacturing plant in Utah for propellant reloading. The remaining SRB components are taken to an assembly and refurbishment facility several miles south of Complex 39 where they are reconditioned and readied for future Space Shuttle launches.
The solid rocket Assembly and Refurbishment Facility consists of four main buildings on a 45-acre site south of the KSC Industrial Area. The site includes facilities for solid rocket processing and servicing and needed administrative offices.
SRB components including aft and forward skirts, frustums, nose caps, recovery systems, electronics and instrumentation as well as elements of the trust vector control system, are refurbished, assembled and tested here.
The Rotation Processing Building (RPSF), located north of the VAB, is where new and reloaded SRB segments are received after being shipped by rail from the Morton-Thiokol's Utah plant. Completed aft skirt assemblies from the Assembly and Refurbishment Facility are integrated here with the SRB aft segments. The remaining SRB components are integrated with the booster stack surge building -- during final mating operations in the VAB.
The two Surge Buildings store SRB flight segments stored after they have been transferred from the nearby Rotation Processing Building. The segments remain there until they are moved to the VAB for integration with other flight-ready SRB components received from the Assembly and Refurbishment Facility.
Between missions, Space Shuttle orbiters are prepared for flight in the Orbiter Processing Facility (OPF) which a resembles modern aircraft maintenance hanger. The OPF is located west of the VAB. It can handle two orbiters at a time.
The OPF consists of two identical high bays connected by a low bay. Each high bay is 197 ft. long, 150 ft. wide and 95 ft. high. Each bay has two 30-ton bridge-type cranes and contains a complex series of platforms which surround the orbiter and permit work access. The high bays also have under-floor trench systems which contain electrical, electronic and communications instrumentation as well as outlets for gaseous nitrogen, oxygen and helium.
In addition, the high bay areas have emergency exhaust systems which are used in the event of a fuel spill in the area. Fire protection systems are located throughout the facility.
The low bay is 233 ft. long, 95 ft. wide and 25 ft. high. In addition to an office annex, it also contains electronic, mechanical and electrical support systems.
Orbiter payloads that must be processed in the horizontal attitude -- such as the Hubble Space Telescope and Spacelab -- are loaded into the orbiter's payload bay in the OPF. Payloads that can be checked out and installed vertically are placed into the orbiter's payload bay at the launch pad.
Orbiter processing procedures are similar to procedures used by airlines for their aircraft maintenance programs.
The Orbiter Modification and Refurbishment Facility (OMRF) is a 50,000 square-foot facility located northwest of the VAB. This facility, completed in the fall of 1987, is used to perform extensive modification, rehabilitation and overhaul of orbiters. The OMRF permits extensive work on orbiters to be performed without disrupting routine operational flight processing of orbiters through the OPF.
The OMRF consists of a single high bay identical to those of the OPF. It is 95 ft. high and has a 2-story low bay area. It contains special work platforms, a 30-ton crane, storage and parts areas as well as office space.
Initially, only non-hazardous work will be performed in the OMRF. However, eventually it will be equipped to perform hazardous operations such as hypergolic deservicing.
Perhaps the most unusual feature of the Logistics Facility is its state-of-the-art storage retrieval parts system which includes automated handling equipment designed to find and retrieve specific Shuttle parts as they are needed.
Space Shuttle components are brought together from various locations throughout the country and assembled at Launch Complex 39 (LC-39) facilities at the Kennedy Space Center. It is in these facilities that the components -- the orbiter, solid rocket booster and external tank -- are assembled into an integrated Space Shuttle vehicle, tested, rolled out to the launch pad and ultimately launched into space.
The VAB is the heart of operations at LC-39. It was originally built to assemble vertically the huge Saturn launch vehicles used for the Apollo, Skylab and the Apollo Soyuz Test Project programs. Its initial construction cost was $117,000,000.
The VAB is one of the largest buildings in the world. It covers a ground area of 8 acres and has a volume of 129,428,000 cubic ft. By contrast, the Pentagon contains 77,025,000 cubic ft. of space. In overall volume, the VAB is exceeded only by the Boeing facility in Washington state where 747 jet aircraft are built.
The VAB is 525 ft. tall, 716 ft. long and 518 ft. wide. It is divided into a high bay area 525 ft. high and a low bay area which is 210 ft. high. A transfer aisle, which runs north and south, connects and transects the two bays thereby allowing the easy movement of Space Shuttle components.
There are four separate bays in the high bay area. The two located on the west side of the building -- called Bays 2 and 4 -- are used for storage and processing of the Shuttle's external tank. The two bays facing to the east -- Bays l and 3 -- are used for the vertical assembly of the Shuttle vehicles atop Mobile Launcher Platforms (MLP).
Movable work platforms, modified to fit the configuration of the Space Shuttle, provide access during the integration and pre- rollout preparations.
During Shuttle integration operations, the SRB segments are transferred from the SRB Rotation Processing and Surge Facility (RPSF) to the VAB. They are hoisted onto the MLP in either High Bay l or 3 and the segments are individually mated to form two complete SRBs.
The external tanks, after arriving by barge from their plant in Louisiana, are inspected and stored in either High Bay 2 or 4 until they are needed. Eventually the tanks are moved to the high bay where the SRBs already have been assembled. There the external tank is attached to the SRB stack.
The Shuttle orbiter, the last element to be mated, is towed from the OPF to the VAB transfer aisle where it is raised to a vertical position and mated to the external tank on the MLP to form the Space Shuttle vehicle.
The VAB's high bay door openings are 456 ft. high from ground to top. The lower door opening is 192 ft. wide and 114 ft. high with four door "leaves" that move horizontally. The upper door opening is 342 ft. high and 76 ft. wide and has seven door leaves that move vertically.
The building has more than 70 lifting devices, including two bridge cranes capable of lifting 250 tons.
The VAB is designed to withstand winds of up to 125 miles an hour. Its foundation rests on more than 4,200 open-end steel pipe pilings which are 16 inches in diameter. The pilings were driven down into bedrock to a depth of 160 ft. -- a total of more than 127 miles of pilings.
A U.S. flag and the bicentennial emblem were painted on the south side of the VAB in 1976 for the nation's bicentennial observance. Over 6,000 gallons of paint were used. The large flag is 209 by 110 ft. in size and is visible at long distances.
Mobile Launcher Platforms (MLP) are the transportable launch bases for the Space Shuttle vehicle. There are three MLPs at KSC. Like most of the major Shuttle-dedicated facilities, the MLPs were originally designed and used for the Apollo/Saturn program. Extensive modifications were necessary to adapt them for Shuttle operations.
The MLPs are impressive steel structures, 25 ft. high, 160 ft. long and 135 ft. wide. They weigh 8,230,000 pounds. At the launch pad, with a fueled Shuttle on their 6-inch-thick decks, they weigh 12,700,000 lb.
There are three exhaust openings in the main deck of an MLP. Two are for the exhaust of the SRBs at launch and the third, a center opening, is for the exhaust from the main engines. SRB exhaust holes are 42 ft. long and 20 ft. wide. The main engine hole is 34 ft. long and 31 ft. wide.
On each side of the main engine exhaust hole there are two large devices called Tail Service Masts. They are 15 ft. long, 9 ft. wide and rise 31 ft. above the MLP deck. Their function is to provide umbilical connections for liquid oxygen and liquid hydrogen lines to fuel the external tank from storage tanks adjacent to the launch pad. Other umbilical lines carry helium and nitrogen, as well as ground electrical power and connections for vehicle data and communications.
At launch, the umbilicals are pulled away from the orbiter and retracted into the masts where protective hoods rotate closed to protect the umbilicals from possible exhaust flame damage.
Another feature of the MLPs is the hydrogen burnoff system which consists of 5-foot-long booms suspended from each Tail Service Mast. Each boom contains four flare-like devices which burn off gas from a pre-ignition flow of liquid hydrogen though the main engines. This prevents a cloud of excess gaseous hydrogen from forming which could explode when the main engines are ignited at launch.
The Space Shuttle vehicle is supported and held on the the MLP by eight attach posts, four on the aft skirt of each SRB. These fit into counterpart posts located in the platform's two SRB support wells. At launch, the Shuttle is freed by triggering explosive nuts which release the giant studs linking the SRB attach posts with the platform support posts.
At their parking locations north of the VAB, in the VAB and at the launch pads, the MLPs rest on six 22-foot-tall pedestals. Also, at the launch pad, four extensible columns are used to stiffen the MLP against rebound loads, should main engine cutoff occur during launch operations.
Fully assembled Space Shuttles mounted on MLPs, are moved from the VAB to the launch pad by enormous tracked vehicles called Crawler Transporters. These vehicles originally were used during the Apollo and Skylab programs and were modified for the Shuttle program, as were most of the major Shuttle facilities at KSC.
The flattop vehicles are about 20 ft. high, 131 ft. long and 114 ft. wide -- about the size of a baseball diamond. They weigh 6 million pounds unloaded and are said to be the largest vehicles of their type in the world. They move on four double-tracked crawlers, each of which is 10 ft. high and 41 ft. long. Each crawler.html">crawler track shoe weighs 1 ton. Unloaded the crawlers can move at a speed of 2 miles an hour. Loaded they literally crawl along at a maximum of 1 mile an hour. It normally takes about 6 hours to make the trip to the launch pad from the VAB.
The vehicles are powered by two 2,750-horsepower diesel engines which drive four l,000 kilowatt generators to provide electrical power to 16 traction motors. The traction motors, operating through gears, turn th crawler tracks.
The vehicles have a leveling system to keep the Shuttle vertical during the trip to the launch pad. This system also provides the leveling needed to move up the ramp leading to the launch pad and to keep the Shuttle level when it is raised and lowered on pedestals at the pad. Once the MLP is attached to the launch pad pedestals, the crawler is backed down the ramp and returned to its parking area.
The maintenance facility for Crawler Transporters is located just north of the OPF where repair and modification of the vehicles is carried out. The weather-protected facility includes a high bay with an overhead crane and a low bay where shops, parts storage and offices are located.
The roadway from the VAB to the launch pads for the Crawler Transporters is equally unique. It is as wide as an eight-lane freeway, consisting of two 40-ft.-wide lanes separated by a 50-ft. median strip. The distance from the VAB to Pad A is 3.44 mile, and to Pad B it is 4.24 mile. The surface on which the transporters move is covered with river gravel 8" thick on curves and 4" thick on the straightaway surfaces.
Kennedy Space Center's Launch Complex 39 (LC-39), has two identical launch pads which, like many Space Shuttle facilities, were originally designed and built for the Apollo lunar landing program. The pads, built in the 1960s, were used for all of the Apollo/Saturn V missions and the Skylab space station program.
Between 1967 and 1975, 12 Saturn V/Apollo vehicles, one Saturn V/Skylab workshop, three Saturn 1B/Apollo vehicles for Skylab crews, and one Saturn 1B/Apollo for the joint U.S.-U.S.S.R. Apollo Soyuz Test Project, were launched from these pads.
Each of the dual launch pads, designated Pads A and B, covers an area of about one-quarter of a square mile. Located not far from the Atlantic Ocean, Pad A is 48 ft. above sea level, while Pad B is 55 ft. above sea level. They are octagonal in shape.
To accommodate the Space Shuttle vehicle, major modifications to the pads were necessary. Initially, Pad A modifications were completed in mid-1978, while Pad B was finished in 1985 and first used for the ill-fated STS 51-L mission in January 1986.
Major pad modifications included construction of new hypergolic fuel and oxidizer support areas at the southwest and southeast corners of the pads; construction of new Fixed Service Structures (FSS); addition of a Rotating Service Structure (RSS); addition of 300,000-gallon water towers and associated plumbing; and, finally, replacement of the original flame deflectors with Shuttle-compatible deflectors.
Following the flight schedule delays resulting from the STS 51-L accident, an additional 105 pad modifications were made. Among them were installation of a sophisticated laser parking system on the Mobile Launch Platform (MLP) to facilitate mounting the Shuttle on the pad, and emergency escape system modifications to provide emergency egress for up to 21 people. The emergency shelter bunker also was modified to allow easier access from the slidewire baskets.
The FSS tower supports the hinge about which the rotary bridge supporting the RSS pivots as it moves between the orbiter checkout position and the retracted position. A hammerhead crane on the FSS provides hoisting capabilities as needed for pad operations. The FSS is 247 ft. high, and the crane is 265 ft. above the surface of the launch pad. Mounted on top of the FSS is a l ightning mast (described later) which is 347 ft. above the pad surface.
Work platforms on the FSS are located at 20-ft. intervals starting at 27 ft. above the pad surface. The FSS has three service arms. These are the orbiter access arm, the external tank hydrogen vent line and access arm and the external tank gaseous oxygen vent arm.
The Orbiter Access Arm (OAA) swings out to the orbiter crew hatch allowing access to the orbiter crew area. At the end of the arm is the environmentally-controlled chamber called the "White Room" which abuts against the orbiter hatch. It can hold up to six people. It is here that the astronaut flight crew is assisted in entering the orbiter.
The OAA remains in its extended position until about 7 minutes before launch. This is to provide emergency egress for the crew, if required. In an emergency, it can be mechanically or manually repositioned in 15 seconds. It is extended and retracted by four hydraulic cylinders. In its retracted position, it is latched to the FSS.
The OAA is located 147 ft. above the pad surface. It is 65 ft. long, 5 ft. wide and 8 ft. high and weighs 52,000 lb.
The external tank hydrogen vent line and access arm consists of a retractable access arm and a fixed support structure. The system allows mating of the external tank umbilicals and contingency access to the tank interior, while at the same time, protecting sensitive components of the system from damage during launch.
The access arm supports small helium and nitrogen lines and electrical cables, all of which are located on an 8" diameter hydrogen vent line.
At SRB ignition, the umbilical is released from the Shuttle vehicle and retracted 33" into its latched position by a system of counterweights. The service lines rise about 18", pivot and drop to a vertical position on the fixed structure where they are protected from damage during launch. All of this activity occurs in just 2 seconds. The access arm itself rotates 120 degrees to its stowed position in approximately 3 minutes.
The fixed structure is mounted on the northeast corner of the FSS about 167 ft. above the pad surface. The access arm is 48 ft. long and weighs 15,000 lb.
This retractable arm supports a vent hood that vacuums away liquid oxygen vapors as they boil off from the external tank. It also supports associated systems such as heated gaseous nitrogen lines, the liquid oxygen vapor ducts and electrical wiring.
Before the liquid oxygen and hydrogen are loaded, the arm is swung into position over the external tank and the vent hood is lowered into position over the liquid oxygen tank vents. Two inflatable "accordion" type seals cover the liquid oxygen vent openings. A heated gaseous nitrogen purge of about 25 lb. per minute flows into the seal cavity, mixing with the cold liquid oxygen vapors preventing the outside from freezing.
At about 2 minutes and 30 seconds before launch, the vent hood is lifted to clear the external tank, and the arm is retracted into the "latchback" position against the FSS. In the event a countdown hold occurs after this time, the arm can be re-extended and the vent hood relowered onto the external tank. When the 2-minute, 30-second mark in the countdown is again reached, the arm once again is retracted.
Also located on the FSS is the emergency exit system -- the "slidewire." This system provides an emergency escape route for persons in the Shuttle vehicle and on the RSS until T-minus 30- seconds in the countdown. Seven slidewires extend from the orbiter access arm level to the ground on the west side of both pads.
A flatbottom basket surrounded by netting is suspended from each wire. Each basket can hold up to three persons, if necessary. When boarded, the basket quickly slides down a l,200-ft.-long wire to the emergency shelter bunker located west of each pad. The baskets are slowed and brought to a stop at the landing zone by a deceleration system consisting of a breaking system catch net and drag chain
The 80-ft.-tall lightning mast extends above the FSS to provide protection from lightning strikes. It is made of fiberglass and is grounded by a cable anchored in the ground l,100 ft. south of the FSS and extends up and over the mast and then back down to a second ground anchor l,100 ft. north of the FSS. The mast functions as an electrical insulator holding the cable away from the FSS and as a mechanical support in rolling contact with the cable. The cable becomes a catenary wire which provides a cone of protection for the pad and vehicle during a lightning storm. The mast support structure is 20 feet tall.
The RSS is supported by a rotating bridge which pivots about a vertical axis. It is located on the west side of each pad's flame trench. The RSS rotates 120 degrees (one-third of a circle). The hinge column sits on the pad surface and is braced to the FSS. Support for the outer end of the bridge is provided by two eight-wheel, motor-driven trucks moving along a circular twin-rail flush with the pad surface. The track crosses the flame trench on a permanent bridge.
The RSS is 102 feet long, 50 ft. wide and 130 ft. high. Its main structure extends from 59 ft. to 189 ft. above the pad floor.
The RSS has orbiter access platforms at five levels. These platforms provide closeout crew access to the payload bay while the orbiter is being serviced for launch. Each platform has independent extendable planks that can be arranged to conform to the shape and overall dimensions of a specific item of Space Shuttle cargo.
The Payload Changeout Room (PCR) is the enclosed, environmentally-controlled portion of the RSS which supports cargo delivery to the pad and subsequent vertical installation into the orbiter payload bay. Seals around the mating surface of the PCR fit against the orbiter and allow the opening of the payload bay or canister doors and removal of the cargo without exposure to outside air and contaminants. A clean-air purge in the PCR maintains environmental control during PCR cargo operations. Cargo is removed from the payload canister and installed vertically in the orbiter by the Payload Ground Handling Mechanism (PGHM).
. The Orbiter Midbody Umbilical Unit (OMBUU) provides access to and permits servicing of the mid-fuselage area of the orbiter. A sliding extension platform and a horizontally-moving line-handling mechanism provide access to the midbody umbilical door on the left side of the orbiter. Liquid oxygen and liquid hydrogen for the fuel cells and gases such as nitrogen and helium are provided through the OMBUU. Overall, the unit is 22 ft. long, 13 ft. wide and 20 ft. high. The OMBUU extends from the RSS at levels ranging from 158 ft. to 176 ft. above the pad surface.
. The hypergolic umbilical system (HUS) carries hypergolic fuel and oxidizer, helium and nitrogen service lines from the FSS to the Shuttle vehicle.
The system also provides for rapidly connecting the lines to and disconnecting them from the vehicle. Six umbilical handling units, manually operated and controlled at the pad, are attached to the RSS. The umbilical handling units consist of three pairs located to the left and right sides of the aft end of the orbiter to serve the Orbital Maneuvering Subsystem (OMS) and Reaction Control System (RCS), the payload bay, and the nose area of the orbiter.
The and the HUS connections with the orbiter are severed when the RSS is returned to its park site position before launch.
The OMS pods are made of an epoxy material that absorbs moisture from the humid Central Florida subtropical climate. Two large clamshell-like enclosures located at the base of the RSS completely surround the OMS pods when the RSS is in position around the orbiter. These enclosures are purged with heated air which absorbs the excess moisture.
. The Sound Suppression Water System is designed to protect the orbiter and its payloads from damage by acoustical energy --tremendous sounds -- reflected from the Mobile Launcher Platform when launch occurs.
The system includes the 290-ft. high water storage tanks adjacent to each launch pad containing 300,000 gallons of water. The water is released just before ignition of the Shuttle's engines. Water pours from 16 nozzles on top of the flame deflectors as well as from outlets in the main engine exhaust hole in the MLP, starting at T-6.6 seconds. When the SRBs are ignited at T-O, a massive torrent of water floods onto the MLP from six large "quench" nozzles or "rainbirds" mounted on its surface.
In addition, water also is sprayed into the primary SRB exhaust holes providing overpressure protection to the Shuttle when the SRBs ignite. Nine seconds after liftoff the peak water flow takes place.
The MLP "rainbirds" are 12 ft. high. The center two are 42 in. in diameter while the other four have a 30 in. diameter. Acoustical levels peak when the Shuttle is about 300 ft. above the MLP.
Design specifications for the Space Shuttle allow withstanding acoustical loads of up to 145 decibels. The sound suppression water system cuts the acoustical level to 142 dB -- three dB below the design requirement.
The SRB Ignition Overpressure Suppression System purpose is to help alleviate the effect of the initial reflected pressure pulse when the SRBs ignite. Without the system, the pulse would exert pressure on the Shuttle's wings and ailerons close to their design limits cause damage to the heat shield tiles. The system was installed after potentially damaging overpressures were noted during the first Shuttle launch in April 1981. The system reduced the overall pulse pressures by two-thirds.
The suppression system consists of two components. The first is a water spray system fed from large headers which provides a cushion of water directed down into and around the primary flame holes. This system is augmented by water bags in the primary and secondary flame holes which provide a mass of water to dampen the "blowback" pressure pulse from the engines.
Hydrogen vapors which occur during the main engine start sequence are exhausted into the engine nozzles just before ignition resulting in a hydrogen-rich atmosphere in the engine bells, which could explode and damage the engine bells. To prevent this, six hydrogen burnoff pre-igniters were installed in the tail service mast. Just before main engine ignition they are activated, igniting the free hydrogen in the the engine nozzles.This precludes what is called "rough combustion" when the main engines ignite.
. The pad surface flame deflectors protect the flame trench floor and the pad surface from the intense heat which occurs at launch. The flame trench is 490 ft. long, 58 ft. wide and 40 ft. high.
The system includes the main engine or orbiter flame deflector which is 38 ft. high, 57.6 ft. wide and weighs l.3 million lb. The SRB flame deflector abuts the orbiter flame deflector to form a flat, inverted V-shaped structure beneath the MLP's three exhaust holes. This deflector is 42.5 ft. high, 42 ft. long and weighs l.l million lb. Both deflectors are made of steel and are covered with a temperature-resistant concrete surface about 5 in. thick.
There also are two movable flame deflectors located on each side of the flame trench. They are 19.5 ft. high, 44 ft. long and 17.5 ft. long.
Propellant servicing of the Space Shuttle's reaction control systems, the booster auxiliary power units and the external tank is performed at the launch pad. Fuel lines lead from various propellant storage facilities to the pad structure and umbilical connections. These facilities include the liquid oxygen and liquid hydrogen and the hypergolic storage and distribution facilities.
Liquid oxygen, the Shuttle's main engine oxidizer, is stored in a 900,000-gallon storage tank located in the northwest corner of each launch pad. These ball-shaped vessels are actually huge vacuum bottles called Dewar bottles which store the liquid oxygen at a temperature of minus 297 degrees F.
Liquid hydrogen is stored in 850,000-gallon storage tanks located in the northwest corner of each launch pad. These tanks also are enormous vacuum bottles able to store the liquid at temperatures below minus 423 degrees F. Liquid hydrogen is an extremely light weight super-cold liquid -- a gallon weighs about a half pound. Because of the liquid's light weight, pumps are not needed to transfer the propellant to the pad. Instead, vaporizers convert a small portion of the tanks liquid hydrogen in the into gas and it is the gas pressure exerted from the top of the tank that moves the liquid into the transfer lines to the pad. Vacuum-jacketed transfer lines permit the hydrogen to flow into the orbiter through the Tail Service Masts.
The orbiter's Orbital Maneuvering Subsystem (OMS) and Reaction Control System (RCS) engines use monomethyl hydrazine as fuel and nitrogen tetroxide as the oxidizer. These toxic fluids can be stored at ambient temperatures. Being hypergolic they ignite on contact with each other. Therefore, they are stored in well-separated locations, at the southwest and southeast corners of the pads.
The vital links between the Launch Processing System in the Launch Control Center (LCC), the ground support equipment and the Shuttle's flight hardware at the pad are provided by elements located in the Pad Terminal Connection Room (PTCR) below the pad's elevated hardstand.
All pad Launch Processing System terminals--called Hardware Interface Modules--interface with the Central Data Subsystem in the LCC.
The Launch Equipment Test Facility (LETF) is located in the KSC Industrial Area, south of the Operations and Checkout Building. It is here that extensive tests of launch-critical ground systems and equipment are conducted. Failure of any of these systems could cause serious consequences during launch.
The LETF can simulate launch events as such vehicle movement due to wind, orbiter engine ignition and liftoff and the effects of solar heating and cryogenic shrinkage. The ability of the ground systems to react properly to these events must be verified before committing the Shuttle to launch.
Examples of the systems tested at the facility include the external tank vent line, the external tank oxygen vent arm, the orbiter's access arm and the rolling beam umbilical system -- all are located in the FSS.
The test facilities include an SRB holddown test stand, a tower simulator, an orbiter access arm random motion simulator, an external tank oxygen vent system simulator, a tail service mast/external tank hydrogen vent line and a random motion and liftoff simulator. Tests in the facility are monitored in a control building on the west side of the LETF complex.
The LETF test equipment was moved to KSC from NASA's Marshall Space Flight Center (MSFC) where many of its components were originally used for similar purposes during the Apollo program.
A wide variety of cargoes -- some deployed from the Shuttle, others carried into space and returned at the end of the mission are delivered to KSC where they undergo final processing, checkout and installation in the orbiter's payload bay.
Space Shuttle cargo processing is performed in parallel with vehicle processing so fully-integrated and tested payloads are ready for orbiter installation at the appropriate time to meet launch schedules
In order to assure an efficient Shuttle turnaround flow, a simulated orbiter-to-cargo interface verification of the entire cargo is performed before it is installed in the orbiter.
Payloads follow one of two functional flows: l) those that are installed horizontally into the payload bay at the Orbiter Processing Facility (OPF), and 2) those that are installed vertically into the payload bay at the launch pad.
Multi-Use Mission Support Equipment. Payload processing is facilitated by special payload handling equipment and devices called the Multi-Use Mission Support Equipment (MMSE). MMSE consists of the Payload Canister, the Payload Canister Transporter, the Payload Strongback and the Payload Handling Fixture
The Payload Canister is a large, environmentally-controlled cargo container in which fully-integrated Shuttle payloads are transported from the Vertical Processing Facility (VPF) to the Payload Changeout Room at the launch pad, the Shuttle Payload Integration Facility (SPIF) or from the Operations and Checkout (O&C) Building to the OPF.
There are two Payload Canisters at KSC. They are 65 ft. long, 18 ft., 7 in. wide. The canisters can hold vertically or horizontally processed payloads of up to 15 ft. in diameter and 60 ft. in length -- matching the cargo-carrying capacity of the orbiter's payload bay. They can hold payloads weighing up to 65,000 lb. and are supported the same way as they are in the payload bay -- by trunnion and keel supports. Their clamshell-shaped doors are the same size as those on the orbiter.
Equally unique are the two vehicles used to move payload canisters the Payload Canister Transporters. They are self-propelled and have 48 wheels, each of which is independently steerable, allowing movement forward, back, sideways or around. They are 65 ft. long and 23 ft. wide. They weigh 140,000 lb. empty. Fully loaded they have a gross weight of 170,500 lb. Their flatbeds can be raised and lowered from 5 to 7 ft. as needed. Their top speed, unloaded is 16. Loaded they have a top speed of 5 mil. an hr. In what is called their "creep mode" they can slow down to a quarter of an inch per second, which is 0.0142 mil. an hr. They can carry the Payload Canister in either a horizontal or vertical position.
The Payload Strongback supports horizontally processed payload sections and postflight payload and airborne support equipment (ASE) removal. It consists of a rigid steel frame with adjustable beams, brackets and clamps designed to prevent bending or twisting of payload elements. Overall, it is 60 ft. long, 16 ft. wide and 9 ft. high weighing 40,000 lb.
The fourth key element of the MMSE is the Payload Handling Fixture. It is designed to handle Shuttle payloads at the contingency landing sites and can be airlifted by Air Force C-5A aircraft.
Vertical Cargo Processing Facilities. Automated, communications satellites, free-flyer pallets and small self-contained payloads (Getaway Specials), including upper stages, are received and processed at NASA facilities at the Cape Canaveral Air Force Station (CCAFS).
Larger Shuttle payloads such as the Tracking and Data Relay Satellite (TDRS), Spacelab and the Hubble Space Telescope are received and prepared for launch in the KSC Industrial Area located on Merritt Island across the Banana River from CCAFS.
Major facilities used by NASA at CCAFS to process deployable payloads include Buildings AE, AO, AM and Hangar S. These facilities have been used since the early days of the U.S. space program. In fact, Hangar S dates back to the Mercury program. It is now used to prepare free-flyer pallets. Buildings AE, AO and AM contain high bay areas where large automated spacecraft are processed. In other facilities at CCAFS, small self-contained payloads are processed at the modified Delta Third Stage Facility building.
After the upper stage and the spacecraft have been mated, they are moved to the Vertical Processing Facility (VPF) in the KSC Industrial Area for integrated testing. Those payloads that use the Delta-class spin-stabilized upper stages undergo checkout at the Payload Spin Test Facility.
All vertically-processed payloads are integrated in the VPF in the KSC Industrial Area. This large facility has an environmentally-controlled high bay and airlock containing 10,153 square ft. of floor space. It is 105 ft. high. Payloads are brought to the high bay through a 71 ft. high, 38 ft.-wide door.
The VPF has two payload workstands each with six fixed platforms. They are serviced by a 2-ton hoist. Two bridge-type cranes -- one with a 25-ton capacity and the other 12 tons -- can be linked to provide a single lift capability of up to 35 tons, if required. Also available is a 10-ton-capacity monorail crane in the airlock. Other KSC vertical payload checkout facilities include:
*Spacecraft Assembly and Encapsulation Facility used to assemble, test, encapsulate and sterilize heavy payloads. Located in the Industrial Area, it has a high bay, two low bays, an airlock, a test cell, a sterilization oven, a control room, as well as administrative offices and mechanical support rooms. The facility was built originally for prelaunch processing of Viking and Voyager planetary mission spacecraft.
*Radioisotope Thermoelectric Generator Storage Building. Located in a remote area of the Industrial Area, radioisotope thermoelectric generators used for spacecraft power-generating systems are stored before they are installed in the spacecraft prior to launch.
*Cargo Hazardous Servicing Facility. A relatively new building where hazardous fuel loading and ordinance servicing takes place. The building is 120 ft. high, 200 ft. long and contains 6,000 square ft. of floor work space. It can accommodate the largest vertical or horizontally loaded spacecraft, including the Payload Canister. It has two complete spacecraft checkout and communications ground stations, an airlock, large rolling doors and two overhead cranes with 15- and 50-ton lifting capabilities. The facility also includes a separate Control Building to monitor payload servicing operations.
*Payload Changeout Room. The PCR attached to the Rotating Service Structure at the launch pad is an environmentally-controlled facility where Shuttle cargo is delivered and vertically installed in the payload bay. Seals around the mating surface of the room inflate, allowing the orbiter's payload bay doors to open for installation of the payload without exposure to outside contamination. A clean air purge in the room maintains the necessary environmental control. Cargo is taken from the Payload Canister and installed vertically in the orbiter using the Payload Ground Handling Mechanism (PGHM). Access is provided by fixed and extensible work platforms.
Vertical Cargo Processing Operations. Processing, testing and integrating vertically-installed payloads is carried out in the VPF under controlled-environment conditions. Processing varies depending on the type of upper stage involved. For example, a spacecraft already mated to a PAM-D is placed directly on one of two workstands after its removal from the Transporter Canister. Those payloads using the IUS upper stage are mated together at the VPF.
No matter where the upper stages are mated to their spacecraft, the entire cargo is assembled on a single workstand where checkout is accomplished by Cargo Integration Test Equipment (CITE), a process that begins with power activation. The overall procedure includes numerous functional tests, computer and communications interface checks and tests of the command and monitor functions.
The last major VPF activity is the Payload Interface Verification Test. This involves verifying payload/cargo mechanical and functional connections are compatible with the orbiter. When this is assured, the cargo is placed in the Payload Canister and taken to the Payload Changeout Room at the launch pad and installed in the orbiter .
The O&C Building is a 5-story, 600,000 square-ft. structure containing offices, laboratories, astronaut crew living quarters, and spacecraft assembly areas. It is located in the Industrial Area, east of the KSC Headquarters Building.
Officially called the Spacelab Assembly and Test Area, the facility is 650 ft. long and 85 ft. wide. It is divided into a high bay, 157 ft. long and 104 ft. high, and a low bay, 475 ft. long and 70 ft. high. Environmentally, the area is maintained at 75 degrees F (plus or minus 2 degrees), with relative humidity controlled at 60 percent or lower.
Within the Spacelab checkout area, there are two Cargo Integration Test Equipment (CITE) assembly and checkout workstands, an engineering model workstand, pallet staging workstands, a rack/floor workstand, a tunnel maintenance area, an airlock maintenance area and two end cone stands. The two CITE workstands are controlled from two automatic test equipment control rooms located on the third floor of the O&C Building.
The mechanical and electrical ground support equipment needed for Spacelab checkout is located in and around the workstands. The facility is designed to handle two separate Spacelab processing flows simultaneously. An orbiter/Spacelab interface adapter and two racks which simulate the orbiter's aft flight deck are attached to the end of the workstands. Orbiter utility interfaces for electrical, gas and fluids are available through ground support equipment cables or lines.
Spacelab Processing and Integration Operations. The Spacelab processing concept allows users to design and develop experiments which can be integrated with other individual experiments into a complete Spacelab payload.
Spacelab processing starts with the integration and checkout of experiment packages and equipment with the appropriate structural mounting elements such as racks for the Spacelab pressurized module and pallet segments for experiments designed to be exposed to the space environment.
Those experiments provided by the European Space Agency (ESA), undergo preliminary integration in Europe before they are shipped to the United States. In fact, all Spacelab payload elements are delivered to KSC as flight-ready as possible.
When individual experiments and payloads are delivered to the O&C Building, the special Spacelab "train" of pallets and racks is assembled using the pallet and/or rack stands. After mechanical build-up of the payload train, these elements are moved to the Spacelab integration workstand and mated with the Spacelab module or the support systems igloo. Operational hardware is refurbished and built-up in parallel with the payload build-up. When the complete Spacelab and payload configuration is ready, the Spacelab module's aft and forward end cones are installed, pallets are positioned and utilities are connected between pallets and the module.
The CITE stand simulates the orbiter and supports highly realistic Space Shuttle/Spacelab electrical and mechanical interface testing.
Once in the OPF the Spacelab is hoisted horizontally from the payload canister transporter by a crane, positioned over the orbiter, lowered, and installed in the payload bay. After installation it is connected to the orbiter interfaces. A payload/orbiter interface test is then conducted to verify the Spacelab is properly installed
When all of these activities are completed, the payload bay doors are closed and latched. The payload bay environment is maintained at 65 degrees F. -- plus or minus 5 degrees -- with a relative humidity of 30 to 50 percent. The orbiter is then powered down and moved to the VAB where it is mated to the external tank and the SRBs. The Spacelab payload requires no further access before launch, although it is possible to open the payload bay doors and reach the Spacelab using the Payload Ground Handling Mechanism, if required.
After movement to the launch pad, the Space Shuttle and the MLP are mated "hard down" on the pad and umbilicals are connected. The Shuttle again is powered up and preparations for launch proceed.
Processing of "Getaway Special" payloads -- officially called small self-contained payloads -- is carried out at the Getaway Special Facility on the Cape Canaveral Air Force Station (CCAFS) in what was formerly the Delta Third Stage Facility.
Since these payloads are self-contained they require only limited interfaces with the orbiter. Therefore, they do not need to be processed in the CITE facility. Instead, once processed at the Getaway Special Facility, they are mounted on a bridge beam in the payload bay while the orbiter is undergoing checkout and testing in the OPF.
Life sciences payloads are usually processed in a manner similar to other horizontally-integrated payloads. The live specimens used for these payloads are housed at Hangar L on the CCAFS, where facilities include laboratories, specimen holding areas and offices for principal investigators.
Life sciences programs are managed for NASA by the Ames Research Center, Mountain View, Calif. KSC is responsible for life sciences payload operations and logistical support.
At the launch pad, live specimens or those already in flight containers, are placed in the orbiter in one of two ways: by opening the payload bay doors and installing the specimens from a special access platform mounted on the Payload Ground Handling Mechanism (PGHM), or through the crew entry hatch with the specimens in containers which are then mounted on the orbiter middeck area.
The Department of Defense (DOD) conducts its own payload build-up and integration at the CCAFS under secure conditions. These procedures are similar to NASA's.
DOD payloads usually arrive by aircraft at the Skid Strip on CCAFS. Those requiring assembly and other testing are taken to an assembly area such as the Air Force-operated Satellite Assembly Building on CCAFS. When work there is completed, the payload is moved to the Shuttle Payload Integration Facility (SPIF) which is quite similar to the VPF at KSC. The SPIF is located in the Solid Motor Assembly Facility Building (SMAB) at the Titan Integrate, Transfer and Launch Complex.
Payloads that need little assembly go directly from the Skid Strip to the SPIF. It is at the SPIF where upper stages are mated with the spacecraft, as required.
Once the cargo elements are mated, cargo processing procedures are the same as those followed by NASA. For example, integration testing uses the DOD Orbiter Functional Simulator, a system very similar to the Cargo Integration Test Equipment at KSC. Once the complete payload is checked out it is placed in a NASA-provided canister for transport from the SPIF to the launch pad.
At the launch pad, the DOD cargo is placed in the Payload Changeout Room on the Rotating Service Structure. From there it is installed in the payload bay for final checkout and interface verification testing. Once testing activities are complete the payload and payload bay are closed out for flight. Click Here for LAUNCH CONTROL CENTER