KSC's Automated Launch Processing System

To maintain the desired launch rate, Space Shuttle vehicles must be assembled, checked out and launched as quickly and inexpensively as safety requirements permit. This pace is made possible by the Launch Processing System, or LPS -- a highly automated, computer- controlled system that oversees the entire checkout and launch process.

The LPS continually monitors the Space Shuttle and its ground components, including its environmental controls and propellant loading equipment. Temperatures, pressures, flow rates, voltages, valve and switch positions and many other critical parameters are monitored several times times each second to see if they are performing as expected. If any reading deviates from normal, the LPS automatically alerts the proper system operator who can then apply human intelligence to the problem.

The checkout and launch process begins with the arrival of Space Shuttle components at Kennedy Space Center. The orbiter, once it has arrived at the Shuttle Landing Facility after a previous mission, is taken to the Orbiter Processing Facility (OPF), where it is refurbished and prepared for its next flight. It is then transferred to the huge Vehicle Assembly Building (VAB) for mating with the solid rocket boosters and the external tank.

The booster segments filled with propellants (shipped from the contractor in Utah) are transferred to the VAB from adjacent checkout and storage facilities. Non-propellant booster components are delivered from a nearby refurbishment facility. The external tank, following delivery from the contractor in Louisiana, is checked out and stored in the VAB. It is the only piece of Shuttle hardware that is not reused.

The mating process begins begins with the stacking of the solid rocket boosters on a mobile launcher platform inside the VAB. The external tank is attached to the boosters, and then the orbiter to the tank. The entire assembly is then carried out to the launch pad by a large tracked vehicle called the crawler-transporter.

The LPS, using digital computers, automatically provides the bulk of the checkout work for the orbiter and much of that for the tank and boosters, reducing the turnaround time between missions and the number of operating personnel involved. It also controls countdown and launch activities. The test engineers operate the LPS through its Checkout, Control and Monitor Subsystem from firing rooms in the Launch Control Center (LCC), the four-story structure located adjacent to the VAB. Two or more Shuttles can be processed simultaneously. During assembly and checkout, the LPS will interface with the solid rocket boosters, external tank, orbiter main engines, and other complex orbiter systems. The LPS also monitors ground support equipment through extensions called hardware interface modules, or HIMS. These modules are located in the OPF, the VAB high bays, the Hypergolic Maintenance Facility in the KSC Industrial Area, the launch pads, the various spacecraft checkout buildings and other sites supporting Shuttle maintenance and checkout. The LPS consists of three major subsystems: Checkout, Control and Monitor; Central Data; and Record and Playback.

Checkout, Control and Monitor Subsystem

The Checkout Control and Monitor Subsystem, or CCMS, consists of operator-manned consoles in the firing rooms, minicomputers, a data transmission system, a data recording area, HIMs, a common data buffer and front-end processors.

Each subsystem operator position in a firing room has its own keyboard and visual display system. The information the human operator needs to make his or her decisions is displayed on computer monitors. Charts and diagrams are shown, pointing out where the unexpected condition exists, and using different colors to indicate the degree of urgency. A red signal means that immediate human attention is needed to prevent possibly serious consequences.

Each group of three keyboards and display systems is considered as one console and operates as a unit. Two consoles, or six operator positions, are usually arranged in a quadrant, or semicircle. All consoles are orchestrated to work together on major tasks through an Integration Console at the front of the firing room. The small computer with each console has an on-line disk storage capacity of five million words to hold all the test procedures to be conducted by that operator and his or her assistants. The checkout and launch functions of each console can be changed, if necessary, by patching and reloading data from the master console.

The master console in the firing room provides the controlling link for transfer of the real-time software from the Shuttle Data Center, or SDC, where it is compiled, to the network of up to 100 parallel minicomputers and microprocessors throughout the LPS. About 40 minicomputers are used during a regular launch.

The number of personnel on duty in a firing room at launch time is less than half of the 450 that were required to launch an Apollo/Saturn vehicle. This reduction in manpower is possible because the LPS monitors thousands of measurements on the Space Shuttle and its ground support equipment, compares them to predefined tolerance levels, and displays only those values that are out of tolerance. This selective process is called the exception monitor capability. In many cases, the LPS computers will automatically react to the exception conditions and perform safing or other related functions without test engineer intervention.

Central Data Subsystem and Shuttle Data Center

When the LPS system was first designed, it contained two large-scale computers (Honeywell DPS-90/92T) that stored test procedures, vehicle processing data, a master program library, historical data, pre- and post-test data analyses, and other related data. This system was called the Central Data Subsystem or CDS. In 1999, that system was upgraded to a cluster of high-end minicomputers and is now called the Shuttle Data Center. These computers make an immense amount of data immediately available to the smaller computers of the CCMS, which have much less storage capacity.

The SDC is located on the second floor of the LCC. In addition to the individual data lines and high speed computer networks, it has two major interfaces. The real-time interface receives the space vehicle and ground support processing data from the CCMS. The video simulation interface provides simulated test data to support the testing of computer programs in the firing rooms without actually having a Space Shuttle present.

Record and Playback Subsystem

The primary function of the Record and Playback Subsystem, or RPS, is to record unprocessed Shuttle instrumentation data during tests and launch countdowns. These recordings can then be played back for post-test analysis when firing room personnel wish to troubleshoot Shuttle or LPS problems. In addition, a limited number of selected data signals can be processed for display or evaluation.

The subsystem consists of instrumentation tape recorders, PCM and FM telemetry demultiplexing equipment, direct-write recorders and computers to provide the wide variety of data reduction capabilities necessary to support the launch crew's special needs in problem analysis and isolation. This subsystem also provides certain functions in support of the CCMS and CDS, such as data playback from downrange instrumentation tapes sent to KSC for data analysis by KSC systems engineers.

Altogether, the three subsystems form a highly efficient, automated means of performing what was previously a slow, expensive and labor-intensive process. The LPS greatly increases the performance capability of each test engineer. Automation and computer technology enable each person to do the work for which several people were needed on earlier manned space programs.

System Operations

A typical example of the LPS at work can be shown by following the liquid oxygen tank sequence when a Shuttle is on the pad. Only one console is required for this operation. Its task is to transfer some 529,000 liters (140,000 gallons) of a super-cold liquid at minus 181 degrees C (-295 degrees F) one-third of a mile, from the liquid oxygen tank at the edge of the pad to the external tank.

The console operator performs several programs to verify that the system is ready to begin the fill operation. These programs establish that; 1) All exception monitor limits are set to their standby conditions; 2) All system measurements are being reported; and 3) All mechanical valves are cycled to determine their readiness to operate. The LPS does all this without operator intervention, finishing, unless unusual conditions occur, in about ten minutes.

When the verifications are complete, the operator awaits a "go" signal from the lead test conductor. When this signal comes, the operator pushes a single button marked "Fill." The liquid oxygen loading operation begins, and continues automatically until completion. It includes these major steps:

Some 200 computer programs are required to operate all these phases of action. They operate a primary pump or secondary pump, primary fill valve, etc., throughout a complex piping system. While these programs are in process, some 150 measurements are constantly monitored to be certain all temperatures, pressures, etc., are within limits. If a condition is detected which requires immediate corrective action, the program takes that action and notifies the operator. Less immediate problems are called to the operator's attention for his consideration. The operator has the option to alter the sequence of events or take over control, in the unlikely event that he or she should think it necessary.

The loading of liquid oxygen is only one of hundreds of equally complicated, difficult operations performed automatically by the LPS, while operating under stringent safety and performance requirements. The end result is the launch of a Space Shuttle.

The concepts underlying the LPS can be applied to other, similar complex operations in many industrial applications. They can be adapted to operate as a multipurpose module system anywhere that mechanical and electrical systems are used to provide checkout and operational control. The programs are written in a high level language (GOAL, or Ground Operations Aerospace Language) that is adaptable to several different host computers. What began as a means of reducing costs and turnaround time for Space Shuttle launches may ultimately bring reductions in the costs of thousands of factory operations throughout the industrialized world.

Future Checkout System Needs at KSC

Rapid advancements in digital data processing and communications, plus increased launch processing requirements for the Space Shuttle, have led NASA to call for a replacement for the CCMS subsystem of the LPS. At the same time, a new test control and monitor system for the International Space Station and future NASA launch systems will be needed. All of these requirements will be met through a follow on of the Checkout & Launch Control System (CLCS) Project. The new CLCS design utilizes state-of-the-art, real-time computers; modern graphic displays; multi-tasking software and communications devices; and advanced design, development and testing capabilities.

A building block approach that allows the system to be upgraded with the latest commercial off-the-shelf hardware and software serves as the basis of the CLCS design. This methodology allows CLCS to be adaptable to a wide range of system and testing needs, and to economically sustain a 30-year-plus lifetime.

CLCS has interfaces with flight hardware and ground support equipment; a high-speed, high-capacity, real-time network; a large-scale data base subsystem; multiple archival and retrieval subsystems; a software production facility; a high-speed display network subsystem; and a modern display processing subsystem where operators will control and supervise test and checkout operations from high-quality color graphics workstations. Here, they will be able to perform multiple functions at the same time in a multi-tasking environment, while being provided with information on the status of the test proceedings and the condition of the test article.

Each CLCS firing room will have the capability to support over 100 locally connected computers, and can support multiple tests at the same time. During the tests, up to 50,000 changes in measurements will be monitored every second. If any of these measurements indicate a potentially dangerous condition, the system will respond to the emergency in less than 20 milliseconds. Currently, the old Firing Room 4, now called Operational Control Room 1 (OCR-1) is operational with a CLCS computer set.

International Space Station Checkout Implementation

The Test, Control and Monitor System (TCMS) is an implementation designed to control prelaunch testing and checkout for all ground support equipment, flight hardware and software elements, payloads and experiments for the International Space Station before launch on the Space Shuttle or future unmanned heavy lift vehicles. The TCMS is located in the Space Station Processing Facility (SSPF) at KSC. It is able to support simultaneous testing of multiple launch packages or individual items. Processing is accelerated by the use of computer simulations, which will take the place of components not yet delivered that interface with hardware already at KSC. These simulations save time, since all equipment is not in place before the testing of some components can begin.

Return to NASA Home Page Return to KSC Home Page

Last Updated Thursday, June 28 19:40:52 EDT 2001
Jim Dumoulin (Redacted)