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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,117 records · Page 62
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

Design of a resistojet for Space Station Freedom

In the mid 1990's, NASA will begin assembly of Space Station Freedom, a permanent outpost in a low-earth orbit. For the station to remain in that orbit, an altitude control system must be developed to resist the effects of atmospheric drag. One system being considered by NASA is called a resistojet, and it uses highly pressurized waste gases heated by electrical resistance to provide thrust on the order of 1 Newton. An additional function of the resistojet is to vent waste gases used by the station and its inhabitants. This report focuses on resolving the issues of system performance, flow and heater control, and materials selection and designing test procedures to resolve, by experimentation, any remaining issues. The conceptual model of the resistojet consists of a shell wrapped by a resistive coil with gases flowing internally through the tube with additional components such as regulators, transducers, and thermocouples. For system performance, the major parameters were calculated from the desired thrust range, the pressure within the resistojet and the cold flow mode of operation; waste gases were analyzed at 100 percent capacity and between 58.95 kPa and 552 kPa. The design team found that any ventilation under all conditions would produce thrust, and therefore, it was decided to limit the design of the ventilation function. The design team proceeded with a simplified model to determine the nozzle throat diameter and chamber diameter.

Garza, Jose↗
NASA NTRS1993

Berthing of Space Station Freedom using the shuttle remote manipulator system

A large-angle, flexible, multi-body, dynamic modeling capability was developed to help validate analytical simulations of the dynamic motion and control forces which occur while berthing of Space Station Freedom to the Shuttle Orbiter during early assembly flights. The dynamics and control of the station, the attached Shuttle Remote Manipulator System, and the Orbiter during a berthing maneuver are described. Emphasis is placed on the modeling of the Shuttle Remote Manipulator System in the multi-body simulation. The influence of the elastic behavior of the station and of the Remote Manipulator System on the attitude control of the station/Orbiter system during the maneuver is investigated.

Cooper, Paul↗
NASA NTRS1993

Heavy-lift vehicle-launched Space Station method and apparatus

Methods and apparatus are provided for a single heavylift launch to place a complete, operational space station on-orbit. A payload including the space station takes the place of a Shuttle Orbiter using the launch vehicle of the Shuttle Orbiter. The payload includes a forward shroud, a core module, a propulsion module, and a transition module between the core module and the propulsion module. The essential subsystems are pre-integrated and verified on Earth. The core module provides means for attaching international modules with minimum impact to the overall design. The space station includes six control moment gyros for selectably operating in either LVLH (local-vertical local-horizontal) or SI (solar inertial) flight modes.

Wade, Donald C.↗
NASA NTRS1993

The value and potential of animal research in enabling astronaut health - Transition from Spacelab to Space Station Freedom

Maintaining astronaut health is a critical aspect of human space exploration. Three decades of space research have demonstrated that microgravity produces significant physiological changes in astronauts. For long-duration missions, the possibility exists that these changes may prevent the achievement of full health and safety and may therefore require countermeasures. Meeting this goal depends on a strong biomedical foundation. Although much research is conducted with humans, some of the most critical work involves a necessary in-depth look into complex problem areas requiring invasive procedures using animals. Much of this research cannot be performed in humans within the bounds of accepted medical practice. A large portion of knowledge and experience in flying animals and applying the data to astronaut health has been obtained through the Spacelab experience and can be applied to a space station situation (expanded to accommodate necessary standardization and flexibility). The objectives of this paper are to (a) discuss the value and potential of animal research in answering critical questions to enable astronaut health for advanced missions, (b) discuss how previous Spacelab operational experience in animal studies can be applied to facilitate transition into a space station era, and (c) review capabilities of biological facilities projected for Space Station Freedom.

Garshnek, V.↗
NASA NTRS1993

KSC ground operations planning for Space Station

At the Kennedy Space Center (KSC) in Florida, processing facilities are being built and activated to support the processing, checkout, and launch of Space Station elements. The generic capability of these facilities will be utilized to support resupply missions for payloads, life support services, and propellants for the 30-year life of the program. Special Ground Support Equipment (GSE) is being designed for Space Station hardware special handling requirements, and a Test, Checkout, and Monitoring System (TCMS) is under development to verify that the flight elements are ready for launch. The facilities and equipment used at KSC, along with the testing required to accomplish the mission, are described in detail to provide an understanding of the complexity of operations at the launch site. Assessments of hardware processing flows through KSC are being conducted to minimize the processing flow times for each hardware element. Baseline operations plans and the changes made to improve operations and reduce costs are described, recognizing that efficient ground operations are a major key to success of the Space Station.

Lyon, J. R.↗
NASA NTRS1994

The controlled ecological life support system Antarctic analog project: Analysis of wastewater from the South Pole Station, Antarctica, volume 1

The Controlled Ecological Life Support system (CELSS) Antarctic Analog Project (CAAP) is a joint National Science Foundation (NSF) and NASA project for the development, deployment and operation of CELSS technologies at the Amundsen-Scott South Pole Station. NASA goals are operational testing of CELSS technologies and the conduct of scientific studies to facilitate technology selection and system design. The NSF goals are that the food production, water purification, and waste treatment capabilities which will be provided by CAAP will improve the quality of life for the South Pole inhabitants, reduce logistics dependence, and minimize environmental impacts associated with human presence on the polar plateau. This report presents an analysis of wastewater samples taken from the Amundsen-Scott South Pole Station, Antarctica. The purpose of the work is to develop a quantitative understanding of the characteristics of domestic sewage streams at the South Pole Station. This information will contribute to the design of a proposed plant growth/waste treatment system which is part of the CELSS Antarctic Analog Project (CAAP).

Flynn, Michael T.↗
NASA NTRS1992

Medical care capabilities for Space Station Freedom: A phase approach

As a result of Congressional mandate Space Station Freedom (SSF) was restructured. This restructuring activity has affected the capabilities for providing medical care on board the station. This presentation addresses the health care facility to be built and used on the orbiting space station. This unit, named the Health Maintenance Facility (HMF) is based on and modeled after remote, terrestrial medical facilities. It will provide a phased approach to health care for the crews of SSF. Beginning with a stabilization and transport phase, HMF will expand to provide the most advanced state of the art therapeutic and diagnostic capabilities. This presentation details the capabilities of such a phased HMF. As Freedom takes form over the next decade there will be ever-increasing engineering and scientific developmental activities. The HMF will evolve with this process until it eventually reaches a mature, complete stand-alone health care facility that provides a foundation to support interplanetary travel. As man's experience in space continues to grow so will the ability to provide advanced health care for Earth-orbital and exploratory missions as well.

Doarn, C. R.↗
NASA NTRS1994

A low-cost transportable ground station for capture and processing of direct broadcast EOS satellite data

The Earth Observing System (EOS), part of a cohesive national effort to study global change, will deploy a constellation of remote sensing spacecraft over a 15 year period. Science data from the EOS spacecraft will be processed and made available to a large community of earth scientists via NASA institutional facilities. A number of these spacecraft are also providing an additional interface to broadcast data directly to users. Direct broadcast of real-time science data from overhead spacecraft has valuable applications including validation of field measurements, planning science campaigns, and science and engineering education. The success and usefulness of EOS direct broadcast depends largely on the end-user cost of receiving the data. To extend this capability to the largest possible user base, the cost of receiving ground stations must be as low as possible. To achieve this goal, NASA Goddard Space Flight Center is developing a prototype low-cost transportable ground station for EOS direct broadcast data based on Very Large Scale Integration (VLSI) components and pipelined, multiprocessing architectures. The targeted reproduction cost of this system is less than $200K. This paper describes a prototype ground station and its constituent components.

Davis, Don↗
NASA NTRS1994

Open solutions to distributed control in ground tracking stations

The advent of high speed local area networks has made it possible to interconnect small, powerful computers to function together as a single large computer. Today, distributed computer systems are the new paradigm for large scale computing systems. However, the communications provided by the local area network is only one part of the solution. The services and protocols used by the application programs to communicate across the network are as indispensable as the local area network. And the selection of services and protocols that do not match the system requirements will limit the capabilities, performance, and expansion of the system. Proprietary solutions are available but are usually limited to a select set of equipment. However, there are two solutions based on 'open' standards. The question that must be answered is 'which one is the best one for my job?' This paper examines a model for tracking stations and their requirements for interprocessor communications in the next century. The model and requirements are matched with the model and services provided by the five different software architectures and supporting protocol solutions. Several key services are examined in detail to determine which services and protocols most closely match the requirements for the tracking station environment. The study reveals that the protocols are tailored to the problem domains for which they were originally designed. Further, the study reveals that the process control model is the closest match to the tracking station model.

Heuser, William Randy↗
NASA NTRS1995

Quick Look Report of Acceleration Measurements on Mir Space Station During Mir-16

The NASA Microgravity Science and Applications Division (MSAD) sponsors the Space Acceleration Measurement System (SAMS) to support microgravity science experiments with microgravity acceleration measurements. In the past, SAMS was flown exclusively on the NASA Orbiters. MSAD is currently sponsoring science experiments participating in the Shuttle-Mir Science Program in cooperation with the Russians on the Mir space station. Included in the complement of MSAD experiments and equipment is a SAMS unit installed on the Mir space station. On 25 August 1994, the SAMS unit was launched on a Russia Progress vehicle to the Mir space station. The SAMS unit will support science experiments from the U.S. and Russia in a manner similar to the Orbiter missions by measuring the microgravity environments during the experiment operations. In October 1994, the SAMS unit recorded data on Mir for over fifty-three hours in seven different time periods to survey possible locations for future experiments. This report presents a quick look at the data and the microgravity environment during the time periods in which SAMS data were acquired. The Mir acceleration data were examined to ascertain gross attributes of the data. This report does not present an exhaustive examination of all possible activities due to the short time available to prepare this quick look report and due to the absence of complete timeline information during the SAMS recording time periods. Appendices A, B and C provide plots of the SAMS data for an overview of the microgravity environment at the times that data were recorded. Appendix D describes the procedures to access SAMS data by file transfer protocol (ftp) utilizing the internet. Appendix E contains a user comment sheet.

Delombard, Richard↗
NASA NTRS1995

LDEF's contribution to the selection of thermal control coatings for the Space Station

The design of the Space Station presented new challenges in the selection and qualification of thermal control materials that would survive in low Earth orbit for a duration of up to 30 years. Prior to LDEF, flight data were obtained from Orbiting Solar Observatory (OSO) satellites, a number of Orbiter flights, and limited ground tests. The excellent data obtained from the OSO satellites were based on calorimetry and temperature measurements which were transmitted to Earth; these satellites were not recovered. For some of these flight experiments it was difficult to distinguish between changes due to contamination, atomic oxygen (AO), ultraviolet radiation (UV), particle radiation and the synergistic effects between them. The data from Shuttle flights were primarily focused on developing a better understanding of atomic oxygen (AO) effects. Although UV and AO were present, the relatively short duration of the Orbiter flights, about one week, was viewed as too short to show the effects from UV or possible synergistic interactions with AO and contamination. At the beginning of the program in 1989 there was no established design data base for AO resistant thermal control coatings for the Space Station. Then came the Long Duration Exposure Facility (LDEF). It provided the first long life data for materials exposed and recovered from space with a characterized environment. Post flight analysis proved data on the effects of contamination on optical properties in the ram (velocity) and wake directions and the erosion of Teflon and multilayer insulation (MLI) covers. The results from LDEF confirmed and, in some cases, modified the approach used for the Space Station, as well as helped to focus our development activities. These development activities resulted in a number of new technical solutions which are applicable to many spacecraft surfaces and missions. LDEF also showed the detrimental effects that could occur from silicone contamination, an issue that has not been completely resolved. An investigation was initiated in 1993 on the effects of silicone contamination and was continuing at the time this paper was prepared.

Babel, Henry W.↗
NASA NTRS1995

Automated delay measurement system for an Earth station for Two-Way Satellite Time and Frequency Transfer

The measurement of the difference of the transmit and receive delays of the signals in a Two-Way Satellite Time and Frequency Transfer (TWSTFT) Earth station is crucial for its nanosecond time transfer capability. Also, the monitoring of the change of this delay difference with time, temperature, humidity, or barometric pressure is important for improving the TWSTFT capabilities. An automated system for this purpose has been developed from the initial design at NMi-VSL. It calibrates separately the transmit and receive delays in cables, amplifiers, upconverters and downconverters, and antenna feeds. The obtained results can be applied as corrections to the TWSTFT measurement when, before and after a measurement session, a calibration session is performed. Preliminary results obtained at NMi-VSL will be shown. Also, if available, the results of a manual version of the system that is planned to be circulated in Sept. 1994 together with a USNO portable station on a calibration trip to European TWSTFT Earth stations.

Dejong, Gerrit↗
NASA NTRS1992

Shuttle to Space Station. Heart Assist Implant. Hubble Update. X-30 Mock-Up

Shuttle to Space Station, Heart Assist Implant, Hubble Update, and X-30 Mockup are the four parts that are discussed in this video. The first part, Shuttle to Space Station, is focussed on the construction and function of the Space Station Freedom. While part two, Heart Assist Implant, discusses a newly developed electromechanical device that helps to reduce heart attack by using electric shocks. Interviews with the co-inventor and patients are also included. Brief introduction to Hubble Telescope, problem behind its poor image quality (mirror aberration), and the plan to correct this problem are the three issues that are discussed in part three, Hubble Update. The last part, part four, reviews the X-30 Mockup designed by the staff and students of Mississippi State University.

Source record↗
NASA NTRS1992

Robust H infinity control design for the space station with structured parameter uncertainty

A robust H-infinity control design methodology and its application to a Space Station attitude and momentum control problem are presented. This new approach incorporates nonlinear multi-parameter variations in the state-space formulation of H-infinity control theory. An application of this robust H-infinity control synthesis technique to the Space Station control problem yields a remarkable result in stability robustness with respect to the moments-of-inertia variation of about 73% in one of the structured uncertainty directions. The performance and stability of this new robust H-infinity controller for the Space Station are compared to those of other controllers designed using a standard linear-quadratic-regulator synthesis technique.

Byun, Kuk-Whan↗
NASA NTRS1993

Impact of suntracking on Space Station controllability

The multibody dynamics of the Space Station is studied as affected by the suntracking motions of the photovotaic arrays. Dynamic responses are simulated for the Station being controlled by control moment gyros (CMGs). Controllability is shown to be a function of flight orientation, stage (inertial properties, CP-CG offset) and the suntracking dynamics. For certain combinations of these parameters, the aerodynamic, inertial disturbances and motor torques from alpha joint(s) arising from near-perfect suntracking are too large for the control moment gyro system to control. However, by imposing slight restrictions on the dynamics of the suntracking, CMGs are able to provide Station attitude stability with excellent pointing performance and an excellent microgravity environment.

Chipman, Richard↗
NASA NTRS1995

Heavy-lift vehicle-launched Space Station method and apparatus

Methods and apparatus are provided for a single heavy-lift launch to place a complete, operational space station on-orbit. A payload including the space station takes the place of a shuttle orbiter using the launch vehicle of the shuttle orbiter. The payload includes a forward shroud, a core module, a propulsion module, and a transition module between the core module and the propulsion module. The essential subsystems are preintegrated and verified on Earth. The core module provides means for attaching international modules with minimum impact to the overall design. The space station includes six control moment gyros for selectably operating in either LVLH (local-vertical local-horizontal) or SI (solar inertial) flight modes.

Wade, Donald C.↗
NASA NTRS1995

Alternate assembly sequence databook for the Tier 2 Bus-1 option of the International Space Station

The JSC International Space Station program office requested that SSB prepare a databook to document the alternate space station assembly sequence known as Tier 2, which assumes that the Russian participation has been eliminated and that the functions that were supplied by the Russians (propulsion, resupply, initial attitude control, communications, etc.) are now supplied by the U.S. Tier 2 utilizes the Lockheed Bus-l to replace much of the missing Russian functionality. The space station at each stage of its buildup during the Tier 2 assembly sequence is characterized in terms of of properties, functionality, resource balances, operations, logistics, attitude control, microgravity environment and propellant usage. The assembly sequence as analyzed was defined by JSC as a first iteration, with subsequent iterations required to address some of the issues that the analysis in this databook identified. Several significant issues were identified, including: less than desirable orbit lifetimes, shortage of EVA, large flight attitudes, poor microgravity environments, and reboost propellant shortages. Many of these issues can be resolved but at the cost of possible baseline modifications and revisions in the proposed Tier 2 assembly sequence.

Brewer, L. M.↗
NASA NTRS1993

Virtual egocenters as a function of display geometric field of view and eye station point

The accurate location of one's virtual egocenter in a geometric space is of critical importance for immersion technologies. This experiment was conducted to investigate the role of field of view (FOV) and observer station points in the perception of the location of one's egocenter (the personal viewpoint) in virtual space. Rivalrous cues to the accurate location of one's egocenter may be one factor involved in simulator sickness. Fourteen subjects viewed an animated 3D model, of the room in which they sat, binocularly, from Eye Station Points (ESP) of either 300 or 800 millimeters. The display was on a 190 by 245 mm monitor, at a resolution of 320 by 200 pixels with 256 colors. They saw four models of the room designed with four geometric field of view (FOVg) conditions of 18, 48, 86, and 140 degrees. They drew the apparent paths of the camera in the room on a bitmap of the room as seen from infinity above. Large differences in the paths of the camera were seen as a function of both FOVg and ESP. Ten of the subjects were then asked to find the position for each display that minimized camera motion. The results fit well with predictions from an equation that took the ratio of human FOV (roughly 180 degrees) to FOVg times the Geometric Eye Point (GEP) of the imager: Zero Station Point = (180/FOVg)*GEP

Psotka, Joseph↗