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Technical Paper

Virtual Laboratory (VLAB) Concept Applied in a Life Science Laboratory

As pieces of the International Space Station (ISS) enter their test phase, access to information and data from the test laboratories must be made immediately available to analysts, managers, and customers. The Virtual Laboratory (VLAB) concept provides remote access to laboratory test data and other information, indirectly as archived data or directly as real-time data off the test bed. We applied VLAB to a life support system hardware test (the Trace Contaminant Control System, TCCS) in the Life Support Technology Center (LSTC). In this paper we describe the VLAB concept in the context of the TCCS hardware test.
Technical Paper

Verification of Supply Chain Quality for Perishable Tools

Increased emphasis on standardizing processes and controlling variability in production operations includes validating perishable tools used in daily operations. Even though dealing with reputable manufacturers, many factors including communication, custom specifications and personnel turnover can lead to the perpetuation of mistakes if errors are not discovered and corrective action implemented. However, inspection is costly and inspection costs far outweigh many item costs unless considering product defects. A beneficial balance may be obtained by employing statistical sampling techniques similar to ISO 2859 [1] to verify the quality of incoming tools.
Technical Paper

Use of Electromagnetic and Vacuum Forces on Aircraft Assembly

Decades ago our innovative grandfathers developed the first automated riveting machines based on hard automation using kinematics and tools attached to a C-frame. The C-frame serves multiple functions: First, it holds the upper and lower tools in fixed positions relative to each other; second, it translates upper active tooling forces to the lower tool; and third, it embraces the part placed between the upper and lower tool. C-frames and newly developed yoke, ring and gantry machines, used for low level (first, second) fuselage and wing assembly are growing in size to exorbitant proportions to satisfy requirements of larger and larger structures. High costs are dictated by massive kinematics and complex controls that provide stability, precision, and process speed. All this is mainly needed because we have to carry mechanical forces around the part, from upper to lower tool along the C-frame, gantry, yoke, bridge, etc.
Technical Paper

Universal Splice Machine

There is an increasing demand in the aerospace industry for automated machinery that is portable, flexible and light. This paper will focus on a joint project between BROETJE-Automation and Boeing called the Universal Splice Machine (USM). The USM is a portable, flexible and lightweight automated drilling and fastening machine for longitudinal splices. The USM is the first machine of its kind that has the ability not only to drill holes without the need to deburr, (burrless drilling) but also to insert fasteners. The Multi Function End Effector (MFEE) runs on a rail system that is mounted directly on the fuselage using a vacuum cup system. Clamp up is achieved through the use of an advanced electromagnet. A control cart follows along next to the fuselage and includes an Automated Fastener Feeding System. This paper will show how this new advancement has the capabilities to fill gaps in aircraft production that automation has never reached before.
Technical Paper

Traceable Part Batching Performance Modeling: A Simulation Case Study

This paper addresses a simulation modeling case study of a batching process. The batching process exists in a multi-server, multi-queue aircraft component manufacturing system where all parts and batches are serial numbered for traceability. Every lot of parts requires a unique set of serial numbers and the sequence of batches is required to follow the airplane master production schedule. The study goal was to identify and provide solutions to shorten arrival time differences among parts going to the same batch in a system of more than 100 shared processes. Queue lengths, resource utilization, bottlenecks, and various scenario comparisons were yielded from simulation modeling exercises.
Technical Paper

The 747-400 Dreamlifter - Overview & Mission

The development of new commercial airliners is a very risky proposition. To get it right, airframe manufacturers must balance new technologies and manufacturing methods with global participation and business considerations. The 787 is Boeing's popular new wide body aircraft incorporating state of the art composites design and manufacturing methods. But new technology alone is not enough. A new logistics system was needed to integrate global partners in order to fully benefit from new technologies. The Boeing 747-400 Dreamlifter is a special purpose 747-400 modified to transport Boeing 787 airplane components through various stages of manufacturing.
Journal Article

Role of Power Distribution System Tests in Final Assembly of a Military Derivative Airplane

Boeing has contracts for military application of twin engine airplanes generically identified in this paper as the MX airplane. Unlike previous derivatives, the MX airplanes are produced with a streamlined manufacturing process to improve cost and schedule performance. The final assembly of each MX airplane includes a series of integration tests, called factory functional tests (FFTs), which are modified from those of typical commercial versions and verify correctness of equipment installation and basic functionalities. Two airplanes have been through the production line resulting in a number of FFT lessons learned. Addressed are the power distribution lessons learned: 1) the expanded coverage of the basic automated power-on generation system test, 2) the need for a manual wire continuity test, 3) salient features of the power distribution tests, and 4) keys to make first pass power distribution test smooth and successful.
Technical Paper

Portable Fastener Delivery and Installation System

The Portable Fastener Delivery System or PFDS, has been developed at the Boeing St. Louis facility to streamline the manual fastener installation process. The PFDS delivers various fasteners, on demand, through a delivery tube to an installation tool used by the operator to install the fasteners in an aircraft assembly. This paper describes the PFDS in its current configuration, along with the associated Huck® International (now Alcoa Fastening Systems) installation tooling, as it is being implemented on the F/A-18E/F Nosebarrel Skinning application. As a “portable” system, the PFDS cart can be rolled to any location on the shop floor it might be needed. The system uses a removable storage cassette to cache many sizes and types of fasteners in the moderate quantities that might be required for a particular assembly task. The operator begins the installation sequence by calling for the particular fastener grip length needed using a wireless control pendant.
Technical Paper

Oxygen/Nitrogen Supply and Distribution for the United States On-Orbit Segment of the International Space Station

The on-orbit oxygen and nitrogen supply for the United States On-Orbit Segment (USOS) of the International Space Station (ISS) is provided in tanks mounted on the outside of the Airlock module. Gasses are supplied, for distribution to users within the USOS, via pressure regulators in the Airlock. The on-orbit storage can be replenished with gas that is scavenged from the Space Shuttle, or by direct replacement of the tanks. The supply and distribution system are described in this paper. The users of the gasses are identified. The system architecture is presented. Operational considerations are discussed.
Technical Paper

Node 1 With Advanced Resistive Exercise Device Computational Fluid Dynamics Modeling

This CFD study is aimed at evaluation of the ventilation characteristics within the ISS Node 1 with the Advanced Resistive Exercise Device (ARED) protrusions into ECLS keep-out zones. An assessment of Node 1 airflow characteristics in the presence of the ARED and a human body simulation model has been performed for the current on-orbit configuration of the Node 1 ventilation system. Both the quantitative velocity distribution analysis and qualitative three-dimensional airflow evaluation have shown that the installation of the ARED in the Node 1 radial bay produces a minimal impact on the cabin ventilation characteristics and the crew.
Technical Paper

Modeling Considerations and Stability Analysis of Aerospace Power Systems with Hybrid AC/DC Distribution

The modeling and simulation of electrical power systems has become a primary design tool for the synthesis of aerospace power systems with hybrid AC/DC distribution. Although in the past the use of extensive time domain simulations using detailed models has been favored, the need to study stability and associated phenomena in this type of power systems-having a high penetration of power electronics loads-has transformed the modeling requirements for aerospace applications. This paper explores different modeling aspects required to study both small-signal and large-signal stability in these systems, providing insight into the development of key system component models-variable frequency generators, line-commutated converters, PWM motor drives and constant power loads, as well as the theoretical foundations based on the Generalized Nyquist Criterion and the Lyapunov Direct and Indirect Methods to fully assess the stability conditions of these power systems.
Technical Paper

Microbial Characterization of Internal Active Thermal Control System (IATCS) Hardware Surfaces after Five Years of Operation in the International Space Station

A flex hose assembly containing aqueous coolant from the International Space Station (ISS) Internal Active Thermal Control System (IATCS) consisting of a 2 foot section of Teflon hose and quick disconnects (QDs) and a Special Performance Checkout Unit (SPCU) heat exchanger containing separate channels of IATCS coolant and iodinated water used to cool spacesuits and Extravehicular Mobility Units (EMUs) were returned for destructive analyses on Shuttle return to flight mission STS-114. The original aqueous IATCS coolant used in Node 1, the Laboratory Module, and the Airlock consisted of water, borate (pH buffer), phosphate (corrosion control), and silver sulfate (microbiological control) at a pH of 9.5 ± 0.5.
Technical Paper

Machining-Induced Residual Stress and Distortion

Distortion and buckling of aluminum aerospace components can be caused by machining-induced residual stress or by residual stress induced earlier in material processing. This stress is characterized through layer removal experiments and measurements of surface location. This stress is correlated to two machining process parameters, which can be changed, in order to control distortion and buckling of machined metallic components. Experiments are presented which compare distortion of thin machined parts to distortion of chemically milled parts in order to uncouple material bulk stress from machining-induced stress.
Technical Paper

Liquid Water Content and Droplet Size Distribution Mass Fractions for Wind Milling Engine Fan Blade Ice Accretion Analysis

A procedure for calculating the engine inlet diffuser section liquid water content and mass fractions of liquid water content associated with the water droplet size distribution for wind milling engine ice accretion analysis is presented. Critical fuel reserve calculation for extended twin-engine operation requires the determination of drag increase due to ice accretion on inoperative wind milling engine fan blade and guide vane.
Technical Paper

International Space Station Temperature and Humidity Control Subassembly Hardware, Control and Performance Description

The temperature and humidity of the air within the habitable areas of the International Space Station are controlled by a set of hardware and software collectively referred to as the Temperature and Humidity Control (THC) subassembly. This subassembly 1) controls the temperature of the cabin air based on a crew selected temperature, 2) maintains humidity within defined limits, and 3) generates a ventilation air flow which circulates through the cabin. This paper provides descriptions of the components of the THC subassembly, their performance ranges, and the control approach of the hardware. In addition, the solutions of the design challenges of maintaining a maximum case radiated noise level of NC 45, controlling the cabin air temperature to within ±2°F of a setpoint temperature, and providing a means of controlling microbial growth on the heat exchanger surfaces are described.
Technical Paper

International Space Station Nitrogen System Performance

The Nitrogen System aboard the International Space Station (Station) continues to maintain Station total pressure and support several ongoing scientific and medical tasks. This paper addresses elevated leakage in the Nitrogen System, behavior during events such as nitrogen usage in other parts of the Station, and describes behavioral changes of the nitrogen Regulator/Relief Valve (regulator) since the activation of the Nitrogen System in 2001.
Technical Paper

International Space Station (ISS) Carbon Dioxide Removal Assembly (CDRA) Desiccant/Adsorbent Bed (DAB) Orbital Replacement Unit (ORU) Redesign

The Carbon Dioxide Removal Assembly (CDRA) is a part of the International Space Station (ISS) Environmental Control and Life Support (ECLS) system. The CDRA provides carbon dioxide (CO2) removal from the ISS on-orbit modules. Currently, the CDRA is the secondary removal system on the ISS, with the primary system being the Russian Vozdukh. Within the CDRA are two Desiccant/Adsorbent Beds (DAB), which perform the carbon dioxide removal function. The DAB adsorbent containment approach required improvements with respect to adsorbent containment. These improvements were implemented through a redesign program and have been implemented on units on the ground and returning from orbit. This paper presents a DAB design modification implementation description, a hardware performance comparison between the unmodified and modified DAB configurations, and a description of the modified DAB hardware implementation into the on-orbit CDRA.
Technical Paper

Integrated Orbiter/International Space Station Air Quality Analysis for Post-Mission 2A.1 Risk Mitigation

Crewmember ingress of the International Space Station (ISS) before that time accorded by the original ISS assembly sequence, and thus before the ISS capability to adequately control the levels of temperature, humidity, and carbon dioxide, poses significant impacts to ISS Environmental Control and Life Support (ECLS). Among the most significant considerations necessitated by early ingress are those associated with the capability of the Shuttle Transportation System (STS) Orbiter to control the aforementioned levels, the capability of the ISS to deliver the conditioned air among the ISS elements, and the definition and distribution of crewmember metabolic heat, carbon dioxide, and water vapor. Even under the assumption that all Orbiter and ISS elements would be operating as designed, condensation control and crewmember comfort were paramount issues preceding each of the ISS Missions 2A and 2A.1.
Technical Paper

Integrated Electrical System Testing and Modeling for Risk Mitigation

International Space Station (ISS) Payload Engineering Integration (PEI) organization adopted the advanced computation and simulation technology to develop integrated electrical system models based on the test data of various sub-units. This system model was used end-to-end to mitigate system risk for the integrated Space Shuttle Pre-launch and Landing configurations. The Space Shuttle carries the Multi-Purpose Logistics Module (MPLM), a pressurize transportation carrier, and the Laboratory Freezer for ISS, a freezer rack for storage and transport of science experiments from/to the ISS, is carried inside the MPLM. An end-to-end electrical system model for Space Shuttle Pre-Launch and Landing configurations, including the MPLM and Freezer, provided vital information for integrated electrical testing and to assess Mission success. The Pre-Launch and Landing configurations have different power supplies and cables to provide the power for the MPLM and the Freezer.
Journal Article

Integrated Ball-Screw Based Upset Process for Index Head Rivets Used in Wing Panel Assembly

A new high speed forming process for fatigue rated index head rivets used in wing panel assembly using ball-screw based servo squeeze actuation has been developed. The new process is achieved using a combination of force and position control and is capable of forming to 40,000 lbs at rates of up to 200,000 lbs/second whilst holding the part location to within +/− 10 thousandths of an inch. Multi-axis riveting machines often have positioning axes that are also used for fastener upset. It is often the case that while a CNC is used for positioning control, another secondary controller is used to perform the fastener upset. In the new process, it has been possible to combine the control of the upset process with the machine CNC, thus eliminating any separate controllers. The fastener upset force profile is controlled throughout the forming of the rivet by using a closed loop force control system that has a load cell mounted directly behind the stringer side forming tool.