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NASA's Johnson Space Center opened for business at its 1,620-acre site 25 miles southeast of Houston in February 1964.

Houston was chosen as the site for the center after an investigation of many locations throughout the United States. The selection was announced in September 1961. Personnel began moving their offices from Langley Field in Virginia to Houston in October 1961 and construction began in April 1962.

The responsibilities of the center include the design, development and testing of spacecraft and associated systems for manned flight; the selection and training of astronauts; planning and conducting manned missions; and extensive participation in the medical, engineering and scientific experiments that help man understand and improve his environment.

The facilities were designed and built to house the wide variety of technical and scientific disciplines required for JSC's mission. The center's organization was divided into several directorates responsible for specific functions-spacecraft development, astronaut training or space flight planning, for example. The organization's flexibility allows frequent realignment of the directorates to keep pace with the changing directions of manned space flight. Some of the original directorates have reorganized, merged or split into separate groups; and new directorates have been created as needed.

The Johnson Space Center program offices direct or coordinate the efforts required locally, elsewhere within NASA or by industrial contractors to fulfill specific program responsibilities. The center has program management responsibility for the space shuttle program, its overall systems engineering and system integration, and the definition of elements that require government and contractor coordination. Directorates and program offices are responsible to the center director, who in turn is responsible to the Office of Space Flight at NASA Headquarters in Washington, D.C.

The JSC facilities are situated near Clear Lake on a site that was donated to NASA by Rice University. The facilities comprise approximately 100 different buildings that range in size and use from the nine-story project management building to the tiny traffic control booths at each entrance. While many structures are devoted to office space, others are uniquely designed for special tasks.

Building 30 is the Mission Control Center. The first half of the first floor, the windowless Mission Operations wing, houses the computers, processors, control panels, tape recorders, test boards, wiring, displays, controls and distribution equipment that support activities on the second and third floors. The second half of the first floor, the more conventional looking Operations Support wing, mainly contains office space. Here in the Mission Control Center a systems engineer can determine if life-sustaining oxygen is flowing at the proper rate or if a switch is in the proper position.

Many of the special facilities at JSC are designed to help determine if spacecraft systems and materials can stand up against the rigors of space flight. One such facility is the Space Environment Simulation Laboratory in Building 32. It contains two vacuum chambers: one is 120 feet high by 65 feet in diameter, and the other is 43 feet high by 35 feet in diameter. A complete spacecraft or individual components can be subjected not only to spacelike vacuum but also to temperature extremes from 280 F below zero to 260 F above zero. Nearby, at the Vibration and Acoustic Test Facility in Building 49, space hardware is buffeted by equipment that simulates the shakes and sounds that the spacecraft experiences in flight. In contrast, complete silence is found in the Anechoic Chamber Test Facility in Building 14, where the foam-covered walls, floor and ceiling soak up stray signals during spacecraft communication system tests.

Just as unique are some of the specialized facilities used to test and train the personnel who fly the spacecraft. In the Space Shuttle Orbiter Mockup and Integration Laboratory in Building 9A, astronauts train in full-scale space shuttle orbiter forward crew compartments and in a 60-foot-long payload bay. Across the street is the Lunar Sample Building, Building 31A.

The Weightless Environment Training Facility in Building 29 provides controlled neutral buoyancy in water to simulate weightlessness. The facility is an essential tool in the design, testing and development of spacecraft and crew equipment; the evaluation of body restraints and handholds; the development of new procedures; and the determination of extravehicular capabilities and work load limits. For the astronaut, it allows important preflight training and familiarity with planned crew activities and the dynamics of body motion under weightless conditions.

Most of the time spent in training an astronaut for a specific mission is logged in simulators that duplicate spacecraft equipment and control panels or even the entire spacecraft cabin. The most sophisticated training devices are the mission simulators, which incorporate on-screen projections where the spacecraft windows would be. The scenes are those the crew will see during the real mission. These training devices in the Mission Simulation and Training Facility can be tied in with the Mission Control communication system so that the crews and flight controllers can practice the entire mission many times before actual flight.

Other specialized facilities at JSC include a photography processing laboratory, a technical services shop, a printing plant, cafeterias, a fire department, a dispensary and a visitor center that houses spacecraft from the Mercury, Gemini and Apollo manned space programs. The Johnson Space Center also maintains aircraft for astronaut training, research programs and administrative travel at nearby Ellington Field, and it also operates the White Sands Test Facility in New Mexico.

Hundreds of contracting companies helped build the space program. These companies are located throughout the United States and range in size from small shops employing several people to corporations employing tens of thousands of people. The task of managing these efforts-bringing everything together in the proper place at the right time with confidence that it will work as planned-is monumental. JSC overcomes the distance problem by assigning resident managers to the spacecraft contractors' plants, where they participate in development, manufacturing and testing activities. Regular reviews and progress reports are summarized in status charts that show the progress of all program phases.

Program management defines and controls the many system interfaces to ensure compatibility of crew, spacecraft and launch vehicle; and it establishes quality control and reliability standards, as well as appropriate checkout and test procedures.

Similar management functions are performed by the NASA centers responsible for other aspects of the program: the launch vehicle at the George C. Marshall Space Flight Center in Huntsville, Ala.; tracking and communication systems at the Goddard Space Flight Center in Greenbelt, Md.; and launch facilities at the John F Kennedy Space Center in Florida. The total effort is coordinated by NASA Headquarters to a precise schedule and rigid standards; yet the controls are flexible enough to take advantage of new technology or to recover from failures.


    Since 1965, the Mission Control Center has been the nerve center for America's manned space program. The men and women who work in Building 30 have been vital to the success of every manned space flight since Gemini 4. These teams of experienced engineers and technicians monitor spacecraft systems and activities 24 hours a day during missions, using some of the most sophisticated communication, computer, data reduction and data display equipment available. They watch every movement the crew and spacecraft make, double-check every number to be sure missions are proceeding as expected and provide expertise to deal with the unexpected.

    During the Mercury project, when Mission Control was at Cape Canaveral, Fla., capsules were controlled almost entirely from the ground. The capsule's manual control systems served in most cases as backups to the automated systems, and astronauts relied heavily on ground control for solutions to problems. As spacecraft became more complex in the Gemini years, dependence on the new Mission Control Center in Houston lessened slightly. During Apollo, when distance and communication breaks made it necessary, some onboard systems became primary, while others still relied on direction from Mission Control. The frequent missions of the space shuttle program required a new approach to flight control. Since the orbiter's onboard computers monitor most systems for the flight crew, the ground control team's main responsibilities are to follow flight activities and be prepared for major maneuvers, schedule changes and unanticipated events. Still, from the moment the giant solid rocket boosters ignite at lift-off to the moment the landing gear wheels roll to a stop at the end of a mission, the Mission Control Center is the hub of communication and shuttle support.


    Mission Control's focal points are the two Flight Control rooms, where flight controllers get information from console computer displays or from projected displays that fill the wall at the front of the room. Almost everyone has seen the television pictures of flight controllers working feverishly at their consoles, headsets in place.

    The Mission Control Center contains two functionally identical Flight Control rooms, one on the second floor and one on the third. Only the third-floor Flight Control Room is used for missions carrying classified Department of Defense payloads. Either room can be used for mission control, or both can be used simultaneously to control separate flights. More often, one team of flight controllers conducts a flight while a second team participates in highly realistic training, or simulation, for a future mission.

    Flight controllers who work in the Flight Control rooms represent only the tip of the staffing iceberg in the Mission Control Center. Each of the 20 to 30 flight controllers who sit at consoles in the Flight Control Room has the help of many other engineers and flight controllers who monitor and analyze data in nearby staff support rooms.

    Atop each console are abbreviations for its function. Each console has a ''call sign,'' the name the flight controller uses when talking to other controllers over the various telephone communication circuits. In some cases, console names or initials are the same as the call signs. Mission command and control positions, their initials, call signs and responsibilities are listed below:

    - Flight director (FD), call sign ''Flight''-leads the flight control team and is responsible for overall space shuttle mission and payload operations and all decisions regarding safe, expedient flight.

    - Space communicator (CAPCOM), call sign ''Capcom''-serves as primary communicator between flight control and astronauts. The initials are a holdover from earlier manned flight, when Mercury was called a capsule rather than a spacecraft.

    - Flight dynamics officer (FDO), call sign ''Fido''-plans maneuvers and monitors trajectory in conjunction with guidance officer.

    - Guidance officer (GDO), call sign ''Guidance or Guido''-monitors onboard navigation and guidance computer software.

    - Data processing systems engineer (DPS)-determines status of data processing system, including the five onboard general-purpose computers, flight-critical and launch data lines, the malfunction display system, mass memories and system-level software.

    - Flight surgeon (Surgeon)-monitors crew activities, coordinates the medical operations flight control team, provides crew consultation, and advises flight director of the crew's health status.

    - Booster systems engineer (Booster)-monitors and evaluates performance of space shuttle main engines, solid rocket boosters and external tank during prelaunch and ascent phases of missions.

    - Propulsion systems engineer (PROP)-monitors and evaluates reaction control and orbital maneuvering systems during all phases of flight and manages propellants and other consumables available for maneuvers.

    - Guidance, navigation and control systems engineer (GNC)-monitors all vehicle guidance, navigation and control systems; notifies flight director and crew of impending abort situations; advises crew regarding guidance malfunctions.

    - Electrical, environmental and consumables systems engineer (EECOM)-monitors cryogenic levels for fuel cells, avionics and cabin cooling systems, electrical distribution systems, cabin pressure control systems and vehicle lighting systems.

    - Instrumentation and communications systems engineer (INCO)-plans and monitors the configuration of in-flight communications, television and instrumentation systems.

    - Ground control (GC)-directs maintenance and operation activities affecting Mission Control hardware, software and support facilities; coordinates space flight tracking and data network and Tracking and Data Relay Satellite system with Goddard Space Flight Center.

    - Flight activities officer (FAO)-plans and supports crew activities, checklists, procedures and schedules.

    - Payload officer (Payload)-coordinates onboard and ground system interfaces between the flight control team and payload user and monitors Spacelab and upper stage systems and their interfaces with the payload.

    - Maintenance, mechanical arm and crew systems engineer (MMACS), call sign ''Max''-monitors operation of the remote manipulator arm and the orbiter's structural and mechanical system; follows use of onboard crew hardware and in-flight equipment maintenance.

    - Public affairs officer (PAO)-provides mission commentary to supplement and explain air-to-ground transmissions and flight control operations to the news media and the public.

    During missions in which a Spacelab module is carried in the orbiter's payload bay, additional flight control positions are required. A command and data management systems officer (CMDS) is responsible for data processing systems involving Spacelab's two major computers. The EECOM manages systems extended from the orbiter to the Spacelab, such as power distribution, life support, cooling and cabin fans, which require more complex monitoring. Cryogens for fuel cells, also managed by the EECOM, become more critical for Spacelab missions because of the higher power levels used and because consumption must be monitored and budgeted over a longer period. The DPS controller works closely with the CDMS officer in monitoring additional displays covering nearly 300 items.


    The Multipurpose Support Room groups participate in planning and support functions. Dedicated to multiple flights, they provide planning expertise for future flights, perform periodic support and systems checks on current flights and respond quickly to any in-flight contingency.



    Space shuttle communication and tracking are accomplished through a combination of the Tracking and Data Relay Satellite system (which consists of three geosynchronous satellites-the first put into orbit in 1983, the second to be launched in 1988 and a spare satellite to be launched later); a ground station at White Sands, N. M.; and the ground space flight tracking and data network. When the TDRSS becomes fully operational, the ground-based tracking network will be closed. The NASA communications network, which will be augmented with a domestic satellite, links tracking stations with ground control centers. The TDRSS, which provides the principal coverage for all shuttle flights, makes it possible to monitor the flight almost continuously, increasing the probability of experiment success, reducing the need for onboard data storage and allowing in-flight experiment changes.

    The Mission Control Center is supported by an emergency power building that houses generators and air-conditioning equipment for use if regular power fails. If a catastrophic failure were to shut down the Houston control center, an emergency facility at the White Sands Test Facility would be activated. The emergency control center is a stripped-down version of the Houston control center, incorporating just enough equipment to let the controllers support the flight to its conclusion.

    One of the most interesting Flight Control Room support facilities is the display and control system, a series of projection screens on the front wall for a variety of displays ranging from charts that plot the spacecraft's location to actual television pictures of activities inside the space shuttle, views of Earth, payload deployment and retrieval, and extravehicular work by mission specialists. Other displays show such critical data as elapsed time after launch or the time remaining before a maneuver or other event.

    Flight controllers base many of their decisions or recommendations on the information given by the display and control system. The real-time computer complex processes telemetry and tracking data to update controllers on space shuttle systems. Controllers can call up stored reference data based on simulated flights previously conducted as practice for the actual mission.

    The consoles of the flight controllers in the Flight Control Room, the Multipurpose Support Room and the Payload Operations Control Center include one or more TV screens and switches to let the controller view a data display on a number of different channels. The controller may select the same display shown on the large projection screens or call up data of special interest just by changing channels. A library of prepared reference data is available to display static information, while digital-to-television display generators provide dynamic, or constantly changing, data.

    In the future, these traditional consoles will be augmented with engineering work stations that provide more capability to monitor and analyze data in support of the increasing flight rate. A further update will change the means of computer support. Instead of the current mainframe central computer that drives all flight control consoles, each console will have its own smaller computer designed to monitor a specific system. These smaller computers will be linked in a network so that they can share data.


    The Flight Control Room, with its rows of consoles and its large display screens and flurry of activity, is a familiar sight to people around the world. But other equally busy areas of the Mission Control Center are just as important to the success of a flight. One such area on the first floor contains the network interface processor. It processes incoming digital data and distributes the information on a real-time basis to facilities associated with the Flight Control Room and support room displays. The system also handles the digital command signals to the spacecraft-the up-data link that lets Mission Control do such things as keep the spacecraft guidance computer's facts and figures up to date.

    The data computation complex, also on the first floor, processes incoming tracking and telemetry data and compares what is happening with what should be happening. Often, it does not display the information unless something goes wrong. As the system evaluates factors such as spacecraft position and velocity, it also computes what maneuvers should be made to correct them.

    The complex computes and evaluates on a real-time basis. Through high-speed electronic data from the worldwide tracking station network, including TDRSS, the complex ''sees'' what is happening almost at the instant it happens; and its computations are fast enough to aid in correcting a situation as it develops. The DCC also uses the data to predict where the spacecraft will be at any given time in the flight. In addition, the computers give acquisition information that helps the tracking stations point their antennas at the spacecraft. The complex also monitors and evaluates telemetry information from the spacecraft to be sure that equipment is performing normally.

    There are five primary computers in the DCC, any one of which can be used to support one Flight Control Room. Another can be used simultaneously to support another Flight Control Room. A third can be used simultaneously to support a live mission from the other Flight Control Room or to support a simulated flight for training additional teams of flight controllers. For critical mission phases, one of the computers is used as a dynamic standby, processing identical data concurrently, in case of a computer failure. The computers are also used to develop and perfect the software programs for each flight.

    Another important facility is the voice communications system, which enables flight controllers to talk to one another without having to leave their consoles. The system also connects controllers with specialists in support rooms, with flight crew training facilities (where specific procedures are tested on spacecraft simulators before they are recommended to the mission crew) and with the personnel along the STDN. It also provides the voice link between Mission Control and the spacecraft.

    The separately located simulation checkout and training system enables flight controllers in the Mission Control Center and flight crews in spacecraft simulators at the Johnson Space Center to rehearse a particular procedure or even a complete mission. The system even simulates voice and data reception from the STDN.


    The orbiter crew consists of the commander and pilot. Additional crew members are a mission specialist and one or more payload specialists. The commander and a pilot, or pilot-qualified mission specialist, are needed to operate and manage the orbiter. The makeup of the rest of the crew depends on the mission's requirements, complexity and duration. The detailed responsibilities of the mission and payload specialists are tailored to meet the requirements of each flight. Crew members work 8.5-hour days.

    The commander is responsible for the safety of the crew and has authority throughout the flight to deviate from the flight plan, procedures and assignments if necessary to preserve crew safety or vehicle integrity. The commander is also responsible for the overall execution of the flight plan in compliance with NASA policy, mission rules and Mission Control Center directives.

    The pilot, second in command of the flight, assists the commander in all phases of orbiter flight and is delegated certain responsibilities (e.g., during two-shift orbital operations). The commander or the pilot is also available to perform specific payload operations.

    The mission specialist coordinates payload operations and is responsible to the user for carrying out scientific objectives. The mission specialist resolves conflicts between payloads and approves flight plan changes caused by payload equipment failures. He or she may also operate experiments to which no payload specialist is assigned or may assist the payload specialist. During launch and recovery of payloads, the mission specialist monitors and controls them to ensure the orbiter's safety.

    The payload specialist manages and operates assigned experiments or other payloads and may resolve conflicts between users' payloads and approve flight plan changes caused by payload equipment failures. The payload specialist is cross-trained to assist the mission specialist or other payload specialists in experiment operation. In some instances, the payload specialist may be responsible for all experiments on board. He or she may operate required orbiter and Spacelab payload support systems, such as the instrument pointing subsystem, the command and data management subsystem and the scientific airlocks. The payload specialist also operates certain orbiter systems, such as the hatches and the food and hygiene systems, and is trained in normal and emergency procedures for crew safety.

    The responsibility for on-orbit management of orbiter systems and attached payload support systems and for extravehicular activity and payload movement with the remote manipulator system rests with the basic crew because extensive training is required for safe and efficient operation of these systems. In general, the commander and pilot manage orbiter systems and standard payload support systems, such as Spacelab and inertial upper stage systems; the mission specialist and payload specialists manage payload support systems that are mission dependent and have an extensive interface with the payload, such as the instrument pointing subsystem.


    The space shuttle crew training facilities include mockups, functional trainers, mathematical models compatible with various computer complexes and complete payload (experiment) simulators. The payload simulators emphasize the payload philosophy, operations, malfunctions, objectives or requirements. The training facilities are located either at the Johnson Space Center or at user locations. Several crew training facilities at the center can interface with payloads or experiments.

    An orbiter 1-g trainer, a full-scale flight deck, a middeck, and a midbody (complete with payload bay) are used for crew training in habitability, extravehicular activity, ingress, egress, television operations, waste management, stowage and routine housekeeping and maintenance.

    The orbiter neutral buoyancy trainer, designed for use in the Weightless Environment Test Facility, includes a full-scale crew cabin middeck, airlock and payload bay doors. It simulates a zero-gravity environment for extravehicular training. The facility is 78 feet long, 33 feet wide and 25 feet deep and holds approximately 490,000 gallons of water.

    The shuttle mission simulator contains full-fidelity forward and aft crew stations. In this computer-controlled simulator, mathematical models of systems, consistent with flight dynamics, drive the crew station displays. Used for training on combined systems and flight team operations, it can simulate payload support systems with mathematical models, remote manipulator system dynamic operations with computer-generated imagery, and Spacelab support systems by interfacing with the Spacelab simulator. The SMS can interface with the Mission Control Center for integrated crew/ground simulations.

    The remote manipulator system task trainer consists of an aft crew station mockup, a payload bay mockup and a mechanically operated arm. It simulates payload grappling (in the payload bay), berthing, visual operations, payload bay camera operations and manipulator software operations. The user provides helium-inflatable models to simulate the payload geometrically.

    A Spacelab simulator, consisting of interior core and experiment segments with computer modeling of the Spacelab systems, is used to train flight and ground crews. This simulator is also used as a trainer for crew accommodations, habitability, stowage and safety methods.

    Payload specialist training for an orbiter-only flight requires approximately 180 hours. A flight with Spacelab pallets requires 189 hours of training, and a mission with a Spacelab module requires 203 hours.

    Two months of nearly full-time training approximates 320 hours of available time, half of which is spent in formal classroom and trainer/simulator instruction. The remaining time can be allocated to Johnson Space Center space shuttle payload flight plan integration and reviews, development and review of flight and mission rules, flight technique meetings and flight requirements implementation reviews. For some complex payloads (e.g., multidiscipline), the dedicated training may take more than two months. Payload specialists who have flown before take a proficiency examination and repeat any training necessary.

    Payload specialist training includes tasks necessary for any crew member to function effectively during flight; this training totals approximately 124 hours. Flight-dependent training can be divided into two types: payload discipline training and training necessary to support shuttle/payload integrated operations. The second is characterized by integrated simulations involving the entire flight operations support teams. Approximately 115 hours are devoted to this training.

    Payload specialist training may start as early as two years before the flight.


    Communication links between the orbiter and the space flight tracking and data network through the Tracking and Data Relay Satellite system were verified by the Electronic Systems Test Laboratory at JSC. The system development tests in support of orbital tests began in the fall of 1977; before that, the laboratory supported the successful approach and landing test program.

    The Shuttle Avionics Integration Laboratory is a highly specialized avionics test facility at JSC that houses a high-fidelity, end-to-end, operating avionics system. There are two test stations. The shuttle test station consists of a multistring set of flight-qualifiable avionics equipment located in flight-type equipment bays and shelves, complete with flight-type harnesses and cable runs. The guidance, navigation and control test station contains a rack-mounted avionics hardware complement limited to that necessary to perform guidance, navigation and control testing. Both stations use space shuttle flight software in conjunction with the Marshall Space Flight Center mated elements system and a subset of the Kennedy Space Center launch processing system. The mated elements system provides flight avionics hardware; flight software; flight wire harnesses; and sensor simulations for the external tank, the solid rocket boosters and the space shuttle main engines.

    The Shuttle Avionics Integration Laboratory verifies the functional integrity and compatibility of the integrated space shuttle avionics system, the onboard flight software for all mission phases and the avionics interfaces with the launch processing system for the prelaunch phase. Both SAIL test stations are supported by independent vehicle flight dynamic simulation and test control facilities. Environment, aerodynamics, vehicle dynamics, sensor simulation and scene generation are provided. A space shuttle aerosurface actuator simulator verifies the performance of the avionics hardware and software with the hydraulic aerosurface actuators. Similar simulations verify the performance of the reaction control system/orbital maneuvering system, space shuttle main engines and solid rocket booster thrust vector controls. A remote manipulator system simulation is also available for hardware/software verification.


Table of Contents

Information content from the NSTS Shuttle Reference Manual (1988)
Last Hypertexed Wednesday October 11 17:49:19 EDT 1995
Jim Dumoulin (

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