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The United States Airlock provides the capability to sustain life in the habitable environment of the International Space Station (ISS) and also supports the Extravehicular Activities (EVA) by providing a means for the crew to translate from the pressurized station environment to space vacuum. The Airlock consists of the Crewlock and Equipment Lock pressurized volumes, two high-pressure oxygen and two high-pressure nitrogen gas tanks. The Airlock Environmental Control and Life Support (ECLS) System consists of the following subsystems: Atmosphere Control and Supply (ACS), Atmosphere Revitalization (AR), Fire Detection and Suppression (FDS) and Temperature and Humidity Control (THC). This paper provides an overview of the Airlock ECLS System and details the verification and testing methodologies utilized during the Qualification test program.

To sustain the extra-vehicular activity (EVA) rate required to assemble and maintain the International Space Station (ISS), we must enhance our ability to plan, train for, and execute EVAs. An underlying analysis capability must be in place to ensure EVA access to all external worksites either as a starting point for ground training, to generate information needed for on-orbit training, or to react quickly to develop contingency EVA plans, techniques, and procedures. This paper describes a potential flight experiment for application of custom human modeling analysis to plan and train for EVAs to enhance space station functionality and usability through assembly and operation.

This paper describes the design and testing of a three phase, 200 Amp. per phase, AC power controller intended to replace electromechanical bus tie and cross tie contactors in commercial aircraft electric power systems. In order to design an effective overall electric power system, both the primary transmission subsystem and the secondary distribution subsystem must operate together, controlling the flow of power in a seamless fashion. This is not possible using electromechanical contactors in the primary subsystem.

The McDonnell Douglas Delta family of launch vehicles, in its more than 30-year history, has proven to be the most reliable spacecraft deployment platform for both the US government and the private sector. This success is due to the continuous and focused application of advanced, affordable engineering and manufacturing technologies in all stages of the design, fabrication, assembly, quality assurance, and launch. One of the recent technological breakthroughs that has enhanced the Delta's service capabilities is the development and use of large composite structures in critical components. Among these structures is the payload fairing, which acts as a protective shroud for the spacecraft. Traditional composite manufacturing techniques, however, are very labor-intensive and time-consuming.

The KEEP EAGLE flight test program was conducted from August 1994 until August 1995 at Edwards AFB by a combined government/contractor test team to evaluate improvements to F-15E high angle-of-attack and spin recovery characteristics. This paper will trace the program from its inception in 1992 until conclusion in 1995, with emphasis on the test approach and flight test techniques employed for this high risk program. Specifically, the test approach included novel assessments of spin recovery control power early in the flight test program using controlled build-ups in yaw rate. The program also used simulation effectively to improve test efficiency and maintain test team proficiency with normal and emergency procedures. These techniques allowed a relatively aggressive flight test program without compromising safety. A total of 18 different aircraft configurations were successfully tested, with 146 developed spins completed throughout the course of 81 program flights.

This paper is focusing on considerations pertaining to riveting/fastening systems and assembly methodology currently in use for large aircraft fuselage structures. Discussion of process principles on which current systems are based is addressing distribution of rivets along the aircraft structure, riveting/fastening systems and equipment flexibility. An attempt was made to predict the most probable future equipment development trends based on the need for more efficiency in all aircraft structural assembly and in high level and final assembly areas.

The successes of the long-duration MDA/NASA test programs for advanced life-support systems conducted prior to 1971 were highly dependent on the selection and training of both the test crews that remained inside the test chamber throughout the test periods and the outside operating staff. The operating staff was responsible for overall test performance, crew safety monitoring, operation and maintenance of the test facilities, and collection and maintenance of data. A selection, training, and certification program was developed and performed to ensure operating staff members had the correct technical skills and could work effectively together with the inside crew. A training program was designed to ensure that each selected operating staff member was capable of performing all assigned functions and was sufficiently cross-trained to serve at other positions on a contingency basis, if needed.

A novel robot architecture has been developed which promises cost savings in a variety of applications in Space and on Earth. Utilizing cables in order to effect motion in a general workspace provides large weight savings, as well as high end effector stiffness. The architecture has been built and successfully tested in space. The capability of the robotic system to actuate those switches, dials, and buttons expected in space environments, as well as to read displays and transmit video to earth for operator feedback have been proven, and are discussed herein.

A detailed SINDA-FLUINT thermo-hydraulic math model of the International Space Station Alpha single-phase thermal control system has been developed to evaluate the system steady state and transient responses. The model is being used to determine critical system performance characteristics, such as line sizing, flow distribution, and temperatures of critical components. It is also used to support the design of the control system required to maintain set point temperature and a constant system pressure. In the future the model will be correlated with test data to provide a reliable tool to support the Space Station operation. A detailed description of the model is presented in this paper, together with sample calculations representing critical Space Station operating conditions. Sensitivity of computed results to variations in critical design parameters is also presented. Since the model will continue to evolve and be improved, logical process to be followed is also outlined.

Tactical aircraft have tire lives as low as 3-5 landings per tire causing excessive support costs. The goal of the Improved Tire Life (ITL) program was to begin developing technology to double aircraft tire life, particularly for tactical aircraft. ITL examined not only the tire, but also aircraft/landing gear design, aircraft operations, and the operational environment. ITL had three main thrusts which were successfully accomplished: 1) development of an analytical tire wear model, 2) initiation of technology development to increase tire life, and 3) exploration of new and unique testing methods for tire wear. This paper reports the work performed and the results of the USAF sponsored ITL program.

This paper describes the capabilities of using a time domain analysis to simulate the electrical waveforms on the MIL-STD-1553B data bus using the circuit simulation program SPICE. This simulation was developed to analyze the various data bus architectures of the Space Station Freedom (SSF) propulsion module system. The advantages of this model over frequency domain models is that the waveform is directly calculated, not synthesized, providing a more accurate and detailed waveform representation. Also, nonstandard configurations and effects can be modeled with accurate simulation results. The output of the simulation is an electrical waveform which can be measured at any point in the bus architecture. Therefore it is possible to see the distortion effects on the transmitted signal's waveform at any point on the MIL-STD-1553B data bus. This model accurately simulates the stray impedance effects of all bus components, and is flexible enough to examine any transmitted waveform.

The paper describes the development, implementation, and benefits of a real-time statistical process control (SPC) data acquisition and response system. The system has been installed on four production CNC riveters and provides enhanced, in-process control of automated fastening machine performance. Each system employs commercially available SPC components. These components, coupled with real-time data acquisition computers, have been integrated with the riveter's controllers and sensors to detect process anomalies as they occur. Real-time knowledge of fastening machine performance is the benefit of this system's approach to SPC. Fastener quality is ensured during the fastening cycle, not after sequences (and perhaps hundreds of rivets) have been completed.

A CELSS has been defined based on current or near-term technology. The CELSS was sized to support the metabolic load of four people on the Moon for ten years. A metabolic load of 14 MJ/person/day is assumed, including an average of 2.6 hr of EVA/person/day. Close to 100% closure of water, and oxygen, and 85% closure of the food loop is assumed. With 15% of the calories supplied from Earth, this should provide adequate dietary variety for the crew along with vitamin and mineral requirements. Other supply and waste removal requirements are addressed. The basic shell used is a Space Station Freedom 7.3 m (24 ft) module. This is assumed to be buried in regolith to provide protection from radiation, meteoroids, and thermal extremes. A solar dynamic power system is assumed, with a design life of 10 years delivering power at 368 kWh/kg. Initial estimates of size are that 73 m2 of plant growth area are required, giving a plant growth volume of about 73 m3.

The selection of a life support system for a lunar base depends on many interrelated factors, both programmatic and technical. Many factors are identifiable through the application of a systems engineering approach to the lunar base design, in which base and mission requirements are determined. In addition, there is a range of evolving technology options whose cost and maturity affect their potential for inclusion in base designs. Results of ongoing lunar base design are presented with emphasis on the selection of promising approaches for advanced life support systems that decrease overall cost for a single, permanently inhabited lunar base. We identify critical technology areas that inhibit the selection of closed life support systems and propose alternative basing scenarios to alleviate development and operational costs. In particular, we quantify the cost savings associated with establishing a base at a lunar pole in a region of permanent sunlight.

A method for applying an organic coating to Z-93, an inorganic white thermal control paint, was developed to protect Z-93 from contamination and damage. A layer of FEP Teflon™ was applied over Z-93 to provide a smooth, continuous surface without adversely affecting its optical properties. Additionally, new low-absorptance, controlled-emittance thermal control paints were developed for low Earth orbit (LEO) applications, such as the International Space Station. These paints have a range of infrared emittances from 0.26 to 0.88, and are stable in simulated LEO environments, including atomic oxygen and ultraviolet radiation. Patent applications have been submitted for these concepts.

The Space Constructible Radiator (SCR) Life Test heat pipe performance testing is currently conducted at NASA/Johnson Space Center as part of the Advanced Technology Development Program. The SCR is a dual passage, monogroove heat pipe radiator designed and manufactured by Grumman Aerospace for NASA. The heat pipe has many aerospace applications since it can transport a large amount of heat with a compact lightweight design. As the micro-meteoroid/orbital debris environment worsens, it may be advantageous to add the heat pipe radiator to the Space Station's thermal control system. The SCR Life Test has been operating over the last 10 years and will continue until the year 2000. The overall heat transfer coefficient has decreased from 792 W/K (1500 Btu/Hr-°F) to 475 W/K (900 Btu/Hr-°F) but appears to have stabilized. This paper summarizes the SCR Life Test setup and the test results to date.

This paper defines the value of free-flying cameras to the Space Station. The use of free-flying cameras is an alternative to reliance on fixed cameras. The analysis is based upon results from recent neutral buoyancy evaluations of a free-flying camera known as the Supplemental Camera and Maneuvering Platform (SCAMP). SCAMP was evaluated for inspection and viewing capabilities that will be required by Space Station. Test results demonstrated that a free-flying camera could be used effectively for inspecting structure, viewing labels, providing views for control of extravehicular robotics (EVR) and for ground assistance during extravehicular activity (EVA) tasks.

The size and complexity of Space Station has driven the need for an accurate, reliable analytical tool to assess the extravehicular activity (EVA) crew interfaces at the worksite. On previous spacecraft, each worksite was developed and validated through Neutral Buoyancy underwater testing by the crew using mockups. For spacecraft requiring a significant amount of EVA over large areas, like Space Station, the cost of conducting underwater tests for each of the many hundred worksites becomes prohibitive. Therefore, limited testing must be augmented by accurate graphical analysis. The Unigraphics II, which is the Computer Aided Design (CAD) system for the International Space Station Alpha (ISSA) Product Group 1 design, was selected and developed. It has a major advantage of easy and rapid access to the accurate and updated Space Station design. The design can be rapidly obtained electronically from layouts, detail drawings, assembly drawings or the Electronic Development Fixture (EDF).

The objective of this paper is to present results of MDA's payload vibration isolation system research and development program. A unique isolation system with passive or active capabilities designed to provide isolation down to 10-6 g was developed and tested in our 1-g testbed under simulated microgravity conditions. Fluid and electrical umbilicals are also included in the system. The established isolation system performance requirements were met and the testbed data were used to refine our analytical models for predicting flight performance. Simulations using an updated Space Station configuration showed that the payload microgravity requirement can be met by upgrading the hardware from laboratory to flight tolerances and improving the control system design. The next step is to flight test the systems verified in 1 g on the STS/SPACEHAB using a middeck locker size development unit.

Future military aircraft will demand lower cost and lower weight subsystems that are more reliable, and easier to maintain and support. To identify and develop subsystems integration technologies that could provide benefits such as these to current and future military aircraft, the Air Force Wright Laboratory (WL/FIVE) initiated the Subsystem Integration Technology (SUIT) program in 1991. McDonnell Douglas Aerospace (MDA) together with Pratt and Whitney (PWA), and AlliedSignal Aerospace Systems and Equipment (ASE) was one of three teams that participated in Phase I of the SUIT program. The MDA Team's goal was to conceptually formulate a SUIT approach which would provide significantly reduced weight and costs while increasing cooling and power generation capabilities. These goals were achieved with a new and innovative energy subsystem suite which integrates aircraft and engine subsystem power, cooling, pumping, and controls.