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An overview of NASA Space Station planning activities is given. Among the specific topics addressed are: the role of private contractors in the construction and operation of Space Station; international cooperation in planning Space Station configurations; and optimum management strategies for Space Station planning activities. The division of work packages for the preliminary design definition phase of the Space Station program is described.
The Dynamics Explorer (DE) satellite carries an Auroral Imaging Package which contains filters designed for performing backscatter ultraviolet measurements to measure total column ozone in the Earth's middle and lower atmosphere. Measurements are obtained at 317.5 mm (to measure ozone absorption) and 360 nm (to measure scene reflectivity). In October 1985 and 1986, measurements were obtained near apogee of the Antarctic ozone hole. The only other high spatial resolution measurements were obtained from the Nimbus 7 Total Ozone Mapping Spectrometer (TOMS) experiment. In October 1987, the Dynamics Explorer apogee had precessed into the Northern Hemisphere preventing measurements of the ozone hole. However, measurements should be obtained from DE of the ozone hole in both 1988 and 1989. Considering that the Nimbus 7 TOMS instrument has long exceeded its expected lifetime, the DE Spin Scan Ozone Imager (SOI) experiment could easily play a crucial role in studies of the ozone hole over the next few years.
A vehicle capable of performing the transfer of eight people to and from the Space Station Freedom is currently in the conceptual/preliminary design stages at the NASA Langley Research Center. Structural definition of this Personnel Launch System (PLS) and the considerations leading to it are described. Issues such as cost, technology level, human factors, and maintainability are used as guidelines for the structural definition. A synergistic design technique involving aerodynamics, performance, mission, packaging, and weights and sizing analyses is utilized to evaluate the structural design. A closed-loop design is achieved when the mission requirements are met by each previously mentioned analysis for a particular vehicle weight. Although satisfactory, the structural concept presented herein is not to be treated as a final answer, but one promising solution. An examination of alternative designs and more detailed analyses can be undertaken in order to identify design inadequacies and more efficient approaches.
The current status for manned Mars missions and the associated challenges are summarized. Mission benefits are considered to increase with increasing Mars entry velocity. However, significant benefits accrue at moderate entry velocities between 7 and 8 km/sec, which is the realistically achievable range in view of g-limits and heating constraints. Blunt, low mass/drag coefficient (reference area) vehicles with L/Ds from 0.3 to 0.5 are found to be the preferred configurations, taking into account their adequate control authority and good payload packaging characteristics. The overall design characteristics of Mars aerocapture vehicles can be established with good confidence, using flight and ground test data and the state-of-the-art flow field analysis techniques. The principal challenges are identified as follows: to refine the knowledge of the Martian atmosphere in order to reduce design conservatism, to extend present stagnation region heating analyses to the entire vehicle forebody, and to develop reflective low-wall-catalycity TPS systems for enabling reusable vehicles.
The design of a coplanar waveguide low-pass filter made of YBa2Cu3O(7-delta) (YBCO) on an LaAlO3 substrate is described. Measurements were incorporated into simple models for microwave CAD analysis to develop a final design. The patterned and packaged coplanar waveguide low-pass filter of YBCO, with dimensions suited for integrated circuits, exhibited measured insertion losses when cooled in liquid nitrogen superior to those of a similarly cooled thin-film copper filter throughout the 0 to 9.5 GHz passband. Coplanar waveguide models for use with thin-film normal metal (with thickness either greater or less than the skin depth) and YBCO are discussed and used to compare the losses of the measured YBCO and copper circuits.
The Laser Transmitter Module (LTM) is a three-color Q-switched flashlamp pumped Nd:YAG laser. The original design concept was to package commercially available optics and flashlamp electronics for spaceflight with a power consumption goal of 2200 W and a weight goal of 600 lbs. The optical output was to exceed 200 mJ of IR, 400 mJ of green, and 150 mJ of UV per pulse at 10 Hz. The new space qualified laser exceeds the optical output requirements by 188 percent, 50 percent, and 13 percent in the UR, green, and UV respectively. This output needs only 1500 W at a weight of only 500 lbs. The LTM was delivered to the NASA Langley Research Center in December 1991. Optical characterization is now being completed.
This addendum to the final report provides a description of the work performed under the subject contract. This report describes the work that was performed by SRS Technologies from Jan. 1992 - Jan. 1993. The work that was performed included the following: (1) a study of the Space Station Freedom (SSF) Preliminary Design Review (PDR) data package and an identification of the maintenance concept, structure, implementation plans, training plan, and the LSAR approach; development of a working ability with the ALSTAR and DATA Express software; (3) a review of the SSF maintenance concept; and (4) an update of the ALSTAR data base.
XRONOS is a general purpose timing analysis package. Although it was designed mainly for x-ray astronomy, XRONOS is basically detector and wavelength independent. It has been used to analyze data from the Einstein Observatory, Exosat and Ginga, as well as optical photometry and helioseismology data. It includes programs for: light curve(s), hardness ratio and color-color plotting, epoch folding, power spectrum, autocorrelation, cross correlation, time skewness, and statistical analysis. An overview of XRONOS and walkthrough of a XRONOS session are presented. The QDP/PLT plotting and function fitting program used by XRONOS is outlined and the algorithm and features of XRONOS are detailed.
A joint military-commercial effort to evaluate multichip module (MCM) structures is discussed. The program, Reliability Technology to Achieve Insertion of Advanced Packaging (RELTECH), has been designed to identify the failure mechanisms that are possible in MCM structures. The RELTECH test vehicles, technical assessment task, product evaluation plan, reliability modeling task, accelerated and environmental testing, and post-test physical analysis and failure analysis are described. The information obtained through RELTECH can be used to address standardization issues, through development of cost effective qualification and appropriate screening criteria, for inclusion into a commercial specification and the MIL-H-38534 general specification for hybrid microcircuits.
An orbit prediction software package (Sea Track) was designed to assist High Resolution Picture Transmission (HRPT) stations in the acquisition of direct broadcast data from sea-viewing spacecraft. Such spacecraft will be common in the near future, with the launch of the Sea viewing Wide Field-of-view Sensor (SeaWiFS) in 1994, along with the continued Advanced Very High Resolution Radiometer (AVHRR) series on NOAA platforms. The Brouwer-Lyddane model was chosen for orbit prediction because it meets the needs of HRPT tracking accuracies, provided orbital elements can be obtained frequently (up to within 1 week). Sea Track requires elements from the U.S. Space Command (NORAD Two-Line Elements) for the satellite's initial position. Updated Two-Line Elements are routinely available from many electronic sources (some are listed in the Appendix). Sea Track is a menu-driven program that allows users to alter input and output formats. The propagation period is entered by a start date and end date with times in either Greenwich Mean Time (GMT) or local time. Antenna pointing information is provided in tabular form and includes azimuth/elevation pointing angles, sub-satellite longitude/latitude, acquisition of signal (AOS), loss of signal (LOS), pass orbit number, and other pertinent pointing information. One version of Sea Track (non-graphical) allows operation under DOS (for IBM-compatible personal computers) and UNIX (for Sun and Silicon Graphics workstations). A second, graphical, version displays orbit tracks, and azimuth-elevation for IBM-compatible PC's, but requires a VGA card and Microsoft FORTRAN.
LSODE, the Livermore Solver for Ordinary Differential Equations, is a package of FORTRAN subroutines designed for the numerical solution of the initial value problem for a system of ordinary differential equations. It is particularly well suited for 'stiff' differential systems, for which the backward differentiation formula method of orders 1 to 5 is provided. The code includes the Adams-Moulton method of orders 1 to 12, so it can be used for nonstiff problems as well. In addition, the user can easily switch methods to increase computational efficiency for problems that change character. For both methods a variety of corrector iteration techniques is included in the code. Also, to minimize computational work, both the step size and method order are varied dynamically. This report presents complete descriptions of the code and integration methods, including their implementation. It also provides a detailed guide to the use of the code, as well as an illustrative example problem.
A screening evaluation is being conducted to determine the performance of several glass fabric/vinyl ester composite material systems for use in primary General Aviation aircraft structures. In efforts to revitalize the General Aviation industry, the Integrated Design and Manufacturing Work Package for General Aviation Airframe and Propeller Structures is seeking to develop novel composite materials and low-cost manufacturing methods for lighter, safer and more affordable small aircraft. In support of this Work Package, this study is generating material properties for several glass fabric/rubber toughened vinyl ester composite systems and investigates the effect of environment on property retention. All laminates are made using the Seemann Composites Resin Infusion Molding Process (SCRIMP), a potential manufacturing method for the General Aviation industry.
Plasma-sprayed Bondable Stainless Surface (BOSS) coatings are being developed under the Solid Propulsion Integrity Program's (SPIP) Bondlines Package. These coatings are designed as a steel case preparation treatment prior to insulation lay-up. Other uses include the exterior of steel cases and bonding surfaces of nozzle components. They provide excellent bondability - rubber insulation and epoxy bonds fail cohesively within the polymer - for both fresh surfaces and surfaces having undergone natural and accelerated environmental aging. They have passed the MSFC requirements for protection of inland and sea coast environment. Because BOSS coatings are inherently corrosion resistant, they do not require preservation by greases or oils. The reduction/elimination of greases and oils, known bondline degraders, can increase SRM reliability, decrease costs by reducing the number of process steps, and decrease environmental pollution by reducing the amount of methyl chloroform used for degreasing and thus reduce release of the ozone-depleting chemical in accordance with the Clean Air Act and the Montreal Protocol. The coatings can potential extend the life of RSRM case segments and nozzle components by eliminating erosion due to multiple grit blasting during each use cycle and corrosion damage during marine recovery. Concurrent work for the Air Force show that other BOSS coatings give excellent bondline strength and durability for high-performance structures of aluminum and titanium.
Marshall Space Flight Center teamed with the University of Alabama in Huntsville (UAH) in 1989 on a program involving development of advanced simulation software. Concurrently, the State of Alabama chartered UAH to conduct a technology advancement program in support of the state's apparel manufacturers. In 1992, under contract to Marshall, UAH developed an apparel-specific software package that allows manufacturers to design and analyze modules without making an actual investment -- it functions on ordinary PC equipment. By 1995, Marshall had responded to requests for the package from more than 400 companies in 36 states; some of which reported savings up to $2 million. The National Garment Company of Missouri, for example, uses the system to design and balance a modular line before committing to expensive hardware; for setting up sewing lines; and for determining the composition of a new team.
Loredan Biomedical, Inc.'s LIDO, a computerized physical therapy system, was purchased by NASA in 1985 for evaluation as a Space Station Freedom exercise program. In 1986, while involved in an ARC muscle conditioning project, Malcom Bond, Loredan's chairman, designed an advanced software package for NASA which became the basis for LIDOSOFT software used in the commercially available system. The system employs a "proprioceptive" software program which perceives internal body conditions, induces perturbations to muscular effort and evaluates the response. Biofeedback on a screen allows a patient to observe his own performance.
Ultra-lightweight and inflatable gossamer space structures are designed to be tightly packaged for launch, then deploy or inflate once in space. These properties will allow for in-space construction of very large structures 10 to 1000 meters in size such as solar sails, inflatable antennae, and space solar power stations using a single launch. Solar sails are of particular interest because of their potential for propellantless propulsion. Gossamer structures do, however, have significant complications. Their low mass and high flexibility make them very difficult to test on the ground. The added mass and stiffness of attached measurement devices can significantly alter the static and dynamic properties of the structure. This complication necessitates an alternative approach for characterization. This paper discusses the development and application of photogrammetry and videogrammetry methods for the static and dynamic characterization of gossamer structures, as four specific solar sail applications demonstrate. The applications prove that high-resolution, full-field, non-contact static measurements of solar sails using dot projection photogrammetry are possible as well as full-field, noncontact, dynamic characterization using dot projection videogrammetry.
NASA issued a Request For Information (RFI) to identify technologies that might be available to monitor a list of air pollutants in the ISS atmosphere. After NASA received responses to the RFI, an expert panel was assembled to hear presentations from 9 technology proponents. The goal of the panel was to identify technologies that might be suitable for replacement of the current Volatile Organics Analyzer (VOA) within several years. The panelists consisted of 8 experts in analytical chemistry without any links to NASA and 7 people with specific expertise because of their roles in NASA programs. Each technology was scored using a tool that enabled rating of many specific aspects of the technology on a 4-point system. The maturity of the technologies ranged from well-tested instrument packages that had been designed for space applications and were nearly ready for flight to technologies that were untested and speculative in nature. All but one technology involved the use of gas chromatography for separation, and there were various detectors proposed including several mass spectrometers and ion mobility spectrometers. In general there was a tradeoff between large systems with considerable capability to address the target list and smaller systems that had much more limited capability.
A software package that has been designed to allow authentication for determining if the rover(s) is/are within a set of boundaries or a specific area to access critical geospatial information by using GPS signal structures as a means to authenticate mobile devices into a network wirelessly and in real-time has been developed. The advantage lies in that the system only allows those with designated geospatial boundaries or areas into the server. The Geospatial Authentication software has two parts Server and Client. The server software is a virtual private network (VPN) developed in Linux operating system using Perl programming language. The server can be a stand-alone VPN server or can be combined with other applications and services. The client software is a GUI Windows CE software, or Mobile Graphical Software, that allows users to authenticate into a network. The purpose of the client software is to pass the needed satellite information to the server for authentication.