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At least 577 records · Page 32

An AI Approach to Ground Station Autonomy for Deep Space Communications

This paper describes an architecture for an autonomous deep space tracking station (DS-T). The architecture targets fully automated routine operations encompassing scheduling and resource allocation, antenna and receiver predict generation. track procedure generation from service requests, and closed loop control and error recovery for the station subsystems. This architecture has been validated by the construction of a prototype DS-T station, which has performed a series of demonstrations of autonomous ground station control for downlink services with NASA's Mars Global Surveyor (MGS).

Fisher, Forest↗

ACTS Ka-Band Earth Stations: Technology, Performance, and Lessons Learned

The Advanced Communications Technology Satellite (ACTS) Project invested heavily in prototype Ka-band satellite ground terminals to conduct an experiments program with ACTS. The ACTS experiments program proposed to validate Ka-band satellite and ground-station technology, demonstrate future telecommunication services, demonstrate commercial viability and market acceptability of these new services, evaluate system networking and processing technology, and characterize Ka-band propagation effects, including development of techniques to mitigate signal fading. This paper will present a summary of the fixed ground terminals developed by the NASA Glenn Research Center and its industry partners, emphasizing the technology and performance of the terminals and the lessons learned throughout their 6-year operation, including the inclined orbit phase-of-operations. The fixed ground stations used for experiments by government, academic, and commercial entities used reflector-based offset-fed antenna systems with antennas ranging in size from 0.35 to 3.4 in. in diameter. Gateway earth stations included two systems referred to as the NASA Ground Station (NGS) and the Link Evaluation Terminal (LET).

Reinhart, Richard C.↗

Automatic Weather Station (AWS) Lidar

An autonomous, low-power atmospheric lidar instrument is being developed at NASA Goddard Space Flight Center. This compact, portable lidar will operate continuously in a temperature controlled enclosure, charge its own batteries through a combination of a small rugged wind generator and solar panels, and transmit its data from remote locations to ground stations via satellite. A network of these instruments will be established by co-locating them at remote Automatic Weather Station (AWS) sites in Antarctica under the auspices of the National Science Foundation (NSF). The NSF Office of Polar Programs provides support to place the weather stations in remote areas of Antarctica in support of meteorological research and operations. The AWS meteorological data will directly benefit the analysis of the lidar data while a network of ground based atmospheric lidar will provide knowledge regarding the temporal evolution and spatial extent of Type la polar stratospheric clouds (PSC). These clouds play a crucial role in the annual austral springtime destruction of stratospheric ozone over Antarctica, i.e. the ozone hole. In addition, the lidar will monitor and record the general atmospheric conditions (transmission and backscatter) of the overlying atmosphere which will benefit the Geoscience Laser Altimeter System (GLAS). Prototype lidar instruments have been deployed to the Amundsen-Scott South Pole Station (1995-96, 2000) and to an Automated Geophysical Observatory site (AGO 1) in January 1999. We report on data acquired with these instruments, instrument performance, and anticipated performance of the AWS Lidar.

Rall, Jonathan A.R.↗

Space Station Biological Research Project

NASA Ames Research Center is responsible for the development of the Space Station Biological Research Project (SSBRP) which will support non-human life sciences research on the International Space Station Alpha (ISSA). The SSBRP is designed to support both basic research to understand the effect of altered gravity fields on biological systems and applied research to investigate the effects of space flight on biological systems. The SSBRP will provide the necessary habitats to support avian and reptile eggs, cells and tissues, plants and rodents. In addition a habitat to support aquatic specimens will be provided by our international partners. Habitats will be mounted in ISSA compatible racks at u-g and will also be mounted on a 2.5 m diameter centrifuge except for the egg incubator which has an internal centrifuge. The 2.5 m centrifuge will provide artificial gravity levels over the range of 0.01 G to 2 G. The current schedule is to launch the first rack in 1999, the Life Sciences glovebox and a second rack early in 2001, a 4 habitat 2.5 in centrifuge later the same year in its own module, and to upgrade the centrifuge to 8 habitats in 2004. The rodent habitats will be derived from the Advanced Animal Habitat currently under development for the Shuttle program and will be capable of housing either rats or mice individually or in groups (6 rats/group and at least 12 mice/group). The egg incubator will be an upgraded Avian Development Facility also developed for the Shuttle program through a Small Business and Innovative Research grant. The Space Tissue Loss cell culture apparatus, developed by Walter Reed Army Institute of Research, is being considered for the cell and tissue culture habitat. The Life Sciences Glovebox is crucial to all life sciences experiments for specimen manipulation and performance of science procedures. It will provide two levels of containment between the work volume and the crew through the use of seals and negative pressure. The glovebox will accommodate use by two crew persons simultaneously and the capability for real time video down-link and data acquisition. In house testbeds and Phase B studies of the centrifuge validated the concepts of vibration isolation and autobalancing systems to meet the ISSA microgravity requirements. The vibration isolation system is effective above the centrifuge rotation frequency while the autobalancing system on the rotor removes vibration at and below the rotation rate. Torque of the Station, induced by spin-up/spindown of the centrifuge, can be minimized by controlling spin-up/spin-down rates. The SSBRP and ISSA will provide the opportunity to perform long-term, repeatable and high quality science. The long duration increments available on the Station will permit multigeneration studies of both plants and animals which have not previously been possible. The u-g habitat racks and the eight habitat centrifuge will accommodate sufficient number of specimens to permit statistically significant sampling of specimens to investigate the time course of adaptation to altered gravity environments. The centrifuge will, for the first time, permit investigators to use gravity itself as a tool to investigate fundamental processes, to investigate the intensity and duration of gravity to maintain normal structure and function, to separate the effects of u-g from other environmental factors and to examine artificial gravity as a potential countermeasure for the physical deconditioning observed during space flight.

Johnson, Catherine C.↗

A Mars Micro-Meteorological Station Mission

The Mars Micro-Meteorological Station (Micro-Met) Mission is designed to provide the global surface pressure measurements required to help characterize the martian general circulation and climate system. Measurements of surface pressure distributed both spatially and temporally, coupled with simultaneous measurements from orbit, will enable the determination of the general circulation, structure and driving factors of the martian atmosphere as well as the seasonal CO2 cycle. The influence of these atmospheric factors will in turn provide insight into the overall martian climate system. With the science objective defined as the long term (at least one Mars year) globally distributed measurement of surface atmospheric pressure, a straightforward, near term and low cost network mission has been designed. The Micro-Met mission utilizes a unique silicon micro-machined pressure sensor coupled with a robust and lightweight surface station to deliver to Mars 16 Micro-Met stations via a Med-Lite launch vehicle. The battery powered Micro-Met surface stations are designed to autonomously measure, record and transmit the science data via a UHF relay satellite. Entry, descent and landing is provided by an aeroshell with a new lightweight ceramic thermal protection system, a parachute and an impact absorbing structure. The robust lander is capable of surviving the landing loads imposed by the high altitude landing sites required in a global network. By trading the ability to make many measurements at a single site for the ability to make a single measurement at several sites, the Micro-Met mission design satisfies the requirement for truly global meteorological science.

Merrihew, Steven C.↗

End-to-End Data System Architecture for the Space Station Biological Research Project

The Space Station Biological Research Project (SSBRP) Is developing hardware referred to as the "facility" for providing life sciences research capability on the International Space Station. This hardware includes several biological specimen habitats, habitat holding racks, a centrifuge and a glovebox. An SSBRP end to end data system architecture has been developed to allow command and control of the facility from the ground, either with crew assistance or autonomously. The data system will be capable of handling commands, sensor data, and video from multiple cameras. The data will traverse through several onboard and ground networks and processing entities including the SSBRP and Space Station onboard and ground data systems. A large number of onboard and ground (,entities of the data system are being developed by the Space Station Program, other NASA centers and the International Partners. The SSBRP part of the system which includes the habitats, holding racks, and the ground operations center, User Operations Facility (UOF) will be developed by a multitude of geographically distributed development organizations. The SSBRP has the responsibility to define the end to end data and communications systems to make the interfaces manageable and verifiable with multiple contractors with widely varying development constraints and schedules. This paper provides an overview of the SSBRP end-to-end data system. Specifically, it describes the hardware, software and functional interactions of individual systems, and interface requirements among various entities of the end-to-end system.

Mian, Arshad↗

Monitoring the Microgravity Environment Quality On-board the International Space Station Using Soft Computing Techniques: Preliminary System Performance Results - Part 2

This paper presents the preliminary performance results of the artificial intelligence monitoring system in full operational mode using near real time acceleration data downlinked from the International Space Station. Preliminary microgravity environment characterization analysis result for the International Space Station (Increment-2), using the monitoring system is presented. Also, comparison between the system predicted performance based on ground test data for the US laboratory "Destiny" module and actual on-orbit performance, using measured acceleration data from the U.S. laboratory module of the International Space Station is presented. Finally, preliminary on-orbit disturbance magnitude levels are presented for the Experiment of Physics of Colloids in Space, which are compared with on ground test data. The ground test data for the Experiment of Physics of Colloids in Space were acquired from the Microgravity Emission Laboratory, located at the NASA Glenn Research Center, Cleveland, Ohio. The artificial intelligence was developed by the NASA Glenn Principal Investigator Microgravity Services Project to help the principal investigator teams identify the primary vibratory disturbance sources that are active, at any moment of time, on-board the International Space Station, which might impact the microgravity environment their experiments are exposed to. From the Principal Investigator Microgravity Services' web site, the principal investigator teams can monitor via a dynamic graphical display, implemented in Java, in near real time, which event(s) is/are on, such as crew activities, pumps, fans, centrifuges, compressor, crew exercise, structural modes, etc., and decide whether or not to run their experiments, whenever that is an option, based on the acceleration magnitude and frequency sensitivity associated with that experiment. This monitoring system detects primarily the vibratory disturbance sources. The system has built-in capability to detect both known and unknown vibratory disturbance sources. Several soft computing techniques such as Kohonen's Self-Organizing Feature Map, Learning Vector Quantization, Back-Propagation Neural Networks, and Fuzzy Logic were used to design the system.

Jules, Kenol↗

Amateur Radio On The International Space Station (ARISS) - The First Educational Outreach Program On ISS

Amateur Radio on the International Space Station (ARISS) represents the first educational outreach program that is flying on the International Space Station (ISS). The astronauts and cosmonauts will work hard on the International Space Station, but they plan to take some time off for educational activities with schools. The National Aeronautics and Space Administration s (NASA s) Education Division is a major supporter and sponsor of this student outreach activity on the ISS. This meets NASA s educational mission objective: To inspire the next generation of explorers.. .as only NASA can. The amateur radio community is helping to enrich the experience of those visiting and living on the station as well as the students on Earth. Through ARISS sponsored hardware and activities, students on Earth get a first-hand feel of what it is like to live and work in space. This paper will discuss the educational outreach accomplishments of ARISS, the school contact process, the ARISS international cooperation and volunteers, and ISS Ham radio plans for the future.

Conley, Carolynn Lee↗

Space Station Science Supported by Marshall Space Flight Center

The science program at Marshall Space Flight Center will be reviewed in the context of the overall NASA science program. An overview will be given on how Marshall science supports the International Space Station research program. The Microgravity research capabilities at Marshall's Biological and Physical Space Research Laboratory will be reviewed. The environment in orbit provides a unique opportunity to study Materials Science and Biotechnology in the absence of sedimentation and convection. There are a number of peer-selected investigations that have been selected to fly on the Space Station that have been conceived and are led by Marshall civil service and contractor scientists. In addition to Microgravity research the Station will enable research in New Initiative Research Areas that focus on enabling humans to live, work, and explore the solar system safely. The specific scientific instruments that have been developed for Materials Science and Biotechnology Research on the International Space Station will be discussed.

Whitaker, Ann F.↗

EXPRESS Rack: The Extension of International Space Station Resources for Multi-Discipline Subrack Payloads

The EXpedite the PRocessing of Experiments to Space Station or EXPRESS Rack System was developed to provide Space Station accommodations for subrack payloads. The EXPRESS Rack accepts Space Shuttle middeck locker type payloads and International Subrack Interface Standard (ISIS) Drawer payloads, allowing previously flown payloads an opportunity to transition to the International Space Station. The EXPRESS Rack provides power, data command and control, video, water cooling, air cooling, vacuum exhaust, and Nitrogen supply to payloads. The EXPRESS Rack system also includes transportation racks to transport payloads to and from the Space Station, Suitcase Simulators to allow a payload developer to verify data interfaces at the development site, Functional Checkout Units to allow payload checkout at KSC prior to launch, and trainer racks for the astronauts to learn how to operate the EXPRESS Racks prior to flight. Standard hardware and software interfaces provided by the EXPRESS Rack simplify the integration processes, and facilitate simpler ISS payload development. Whereas most ISS Payload facilities are designed to accommodate one specific type of science, the EXPRESS Rack is designed to accommodate multi-discipline research within the same rack allowing for the independent operation of each subrack payload. On-orbit operations began with the EXPRESS Rack Project on April 24, 2001, with one rack operating continuously to support long-running payloads. The other on-orbit EXPRESS Racks operate based on payload need and resource availability. Sustaining Engineering and Logistics and Maintenance functions are in place to maintain operations and to provide software upgrades.

Sledd, Annette↗

Space Station Freedom Overview

This document explains which countries and agencies participate in the development of Space Station Freedom, what the different structures on the station will be, and who is responsible for constructing them. The systems which will be operational in the baseline configuration of the station are listed, as is its assembly schedule. An overview of plans for space station evolution is also given.

Kohrs, Richard H.↗

Proceedings of the Space Station Freedom Clinical Experts Seminar

These are the proceedings of the Space Station Freedom Health Maintenance Facility 1990 Clinical Experts Seminar held August 27-29, 1990, at the Nassau Bay Hilton, Houston, Texas. Contained within are the agenda, list of medical consultants, executive summary, individual presentations, and the comments generated from the working groups. Issues include the adequacy of current Health Maintenance Facility for Space Station Freedom; impact of having, or not having, an ACRV or physician on board Space Station Freedom; new and developing technologies, techniques, and medications and their impact on the evolving Space Station Freedom, considerations surrounding x-ray, ultrasound, lab, decontamination, blood transfusion, nutrition, safe-haven, computer/telemedicine; suggestions as to how to train the Crew Medical Officer; and, how the consultant network will interface over the next several years.

Billica, Roger P.↗

International Space Station Increment-4/5 Microgravity Environment Summary Report

This summary report presents the results of some of the processed acceleration data measured aboard the International Space Station during the period of December 2001 to December 2002. Unlike the past two ISS Increment reports, which were increment specific, this summary report covers two increments: Increments 4 and 5, hereafter referred to as Increment-4/5. Two accelerometer systems were used to measure the acceleration levels for the activities that took place during Increment-4/5. Due to time constraint and lack of precise timeline information regarding some payload operations and station activities, not a11 of the activities were analyzed for this report. The National Aeronautics and Space Administration sponsors the Microgravity Acceleration Measurement System and the Space Acceleration Microgravity System to support microgravity science experiments which require microgravity acceleration measurements. On April 19, 2001, both the Microgravity Acceleration Measurement System and the Space Acceleration Measurement System units were launched on STS-100 from the Kennedy Space Center for installation on the International Space Station. The Microgravity Acceleration Measurement System supports science experiments requiring quasi-steady acceleration measurements, while the Space Acceleration Measurement System unit supports experiments requiring vibratory acceleration measurement. The International Space Station Increment-4/5 reduced gravity environment analysis presented in this report uses acceleration data collected by both sets of accelerometer systems: The Microgravity Acceleration Measurement System, which consists of two sensors: the low-frequency Orbital Acceleration Research Experiment Sensor Subsystem and the higher frequency High Resolution Accelerometer Package. The low frequency sensor measures up to 1 Hz, but is routinely trimmean filtered to yield much lower frequency acceleration data up to 0.01 Hz. This filtered data can be mapped to arbitrary locations for characterizing the quasi-steady environment for payloads and the vehicle. The high frequency sensor is used to characterize the vibratory environment up to 100 Hz at a single measurement location. The Space Acceleration Measurement System, which deploys high frequency sensors, measures vibratory acceleration data in the range of 0.01 to 400 Hz at multiple measurement locations. This summary report presents analysis of some selected quasi-steady and vibratory activities measured by these accelerometers during Increment- 4/5 from December 2001 to December 2002.

Jules, Kenol↗

Amateur Radio on the International Space Station - Phase 2 Hardware System

The International Space Station (ISS) ham radio system has been on-orbit for over 3 years. Since its first use in November 2000, the first seven expedition crews and three Soyuz taxi crews have utilized the amateur radio station in the Functional Cargo Block (also referred to as the FGB or Zarya module) to talk to thousands of students in schools, to their families on Earth, and to amateur radio operators around the world. Early on, the Amateur Radio on the International Space Station (ARISS) international team devised a multi-phased hardware development approach for the ISS ham radio station. Three internal development Phases. Initial Phase 1, Mobile Radio Phase 2 and Permanently Mounted Phase 3 plus an externally mounted system, were proposed and agreed to by the ARISS team. The Phase 1 system hardware development which was started in 1996 has since been delivered to ISS. It is currently operational on 2 meters. The 70 cm system is expected to be installed and operated later this year. Since 2001, the ARISS international team have worked to bring the second generation ham system, called Phase 2, to flight qualification status. At this time, major portions of the Phase 2 hardware system have been delivered to ISS and will soon be installed and checked out. This paper intends to provide an overview of the Phase 1 system for background and then describe the capabilities of the Phase 2 radio system. It will also describe the current plans to finalize the Phase 1 and Phase 2 testing in Russia and outlines the plans to bring the Phase 2 hardware system to full operation.

Bauer, F.↗

James Webb Space Telescope Station-keeping

The James Webb Space Telescope (JWST) is planned to be launched in 2011 to the Sun- Earth L2 libration point. The resultant delta-Vs (dV) from momentum unloads will perturb the orbit and necessitate frequent station-keeping maneuvers. The station-keeping dV budget is highly sensitive to the direction of the resultant dV vector. A simple spacecraft reorientation prior to each momentum unload will allow some control over the direction of the resultant dV vector. For each inertial momentum vector direction, an optimum spacecraft attitude is determined which gives a resultant dV vector that requires the least amount of station-keeping dV. Using this procedure, the station-keeping dV budget for JWST can be reduced by 60%.

Beckman, Mark↗

MSFC Space Station Program Commonly Used Acronyms and Abbreviations Listing

The Marshall Space Flight Center maintains an active history program to assure that the foundation of the Center's history is captured and preserved for current and future generations. As part of that overall effort, the Center began a project in 1987 to capture historical information and documentation on the Marshall Center's roles regarding Space Shuttle and Space Station. This document is MSFC Space Station Program Commonly Used Acronyms and Abbreviations Listing. It contains acronyms and abbreviations used in Space Station documentation and in the Historian Annotated Bibliography of Space Station Program. The information may be used by the researcher as a reference tool.

Gates, Thomas G.↗

Expert Water Quality Panel Review of Responses to the NASA Request for Information for the International Space Station On-Board Environmental Monitoring System

On August 9, 2003, NASA, with the cooperative support of the Vehicle Office of the International Space Station Program, the Advanced Human Support Technology Program, and the Johnson Space Center Habitability and Environmental Factors Office released a Request for Information, or RFI, to identify next-generation environmental monitoring systems that have demonstrated ability or the potential to meet defined requirements for monitoring air and water quality onboard the International Space Station. This report summarizes the review and analysis of the proposed solutions submitted to meet the water quality monitoring requirements. Proposals were to improve upon the functionality of the existing Space Station Total Organic Carbon Analyzer (TOCA) and monitor additional contaminants in water samples. The TOCA is responsible for in-flight measurement of total organic carbon, total inorganic carbon, total carbon, pH, and conductivity in the Space Station potable water supplies. The current TOCA requires hazardous reagents to accomplish the carbon analyses. NASA is using the request for information process to investigate new technologies that may improve upon existing capabilities, as well as reduce or eliminate the need for hazardous reagents. Ideally, a replacement for the TOCA would be deployed in conjunction with the delivery of the Node 3 water recovery system currently scheduled for November 2007.

Fishman, Julianna L.↗

Cathodes Delivered for Space Station Plasma Contactor System

The International Space Station's (ISS) power system is designed with high-voltage solar arrays that typically operate at output voltages of 140 to 160 volts (V). The ISS grounding scheme electrically ties the habitat modules, structure, and radiators to the negative tap of the solar arrays. Without some active charge control method, this electrical configuration and the plasma current balance would cause the habitat modules, structure, and radiators to float to voltages as large as -120 V with respect to the ambient space plasma. With such large negative floating potentials, the ISS could have deleterious interactions with the space plasma. These interactions could include arcing through insulating surfaces and sputtering of conductive surfaces as ions are accelerated by the spacecraft plasma sheath. A plasma contactor system was baselined on the ISS to prevent arcing and sputtering. The sole requirement for the system is contained within a single directive (SSP 30000, paragraph 3.1.3.2.1.8): "The Space Station structure floating potential at all points on the Space Station shall be controlled to within 40 V of the ionospheric plasma potential using a plasma contactor." NASA is developing this plasma contactor as part of the ISS electrical power system. For ISS, efficient and rapid emission of high electron currents is required from the plasma contactor system under conditions of variable and uncertain current demand. A hollow cathode plasma source is well suited for this application and was, therefore, selected as the design approach for the station plasma contactor system. In addition to the plasma source, which is referred to as a hollow cathode assembly, or HCA, the plasma contactor system includes two other subsystems. These are the power electronics unit and the xenon gas feed system. The Rocketdyne Division of Boeing North American is responsible for the design, fabrication, assembly, test, and integration of the plasma contactor system. Because of technical and schedule considerations, the NASA Lewis Research Center was asked to manufacture and deliver the engineering model, the qualification model, and the flight HCA units for the plasma contactor system as government furnished equipment. To date, multiple units have been built. One cathode has demonstrated approximately 28 000-hr lifetime, two development HCA units have demonstrated over 15 000-hr lifetime, and one HCA unit has demonstrated more than 38 000 ignitions. All eight flight HCA's have been manufactured, acceptance tested, and are ready for delivery to the flight contractor.

Patterson, Michael J.↗