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At least 253 records · Page 14

Freedom is an international partnership

The NASA Space Station Freedom (SSF) project initiated in 1984 is a collaborative one among the U.S., Japan, Canada, and the 10 nations participating in ESA. The SSF partners have over the last six years defined user requirements, decided on the hardware to be manufactured, and constructed a framework for long-term cooperation. SSF will be composed of user elements furnished by the foreign partners and a U.S.-supplied infrastructure encompassing the truss assembly, electrical power system, and crew living quarters. The U.S. will also furnish a lab and a polar-orbit platform; ESA, a second lab and the coorbiting Free-Flying Laboratory, as well as a second polar platform. Japan's Japanese Experiment Module shall include an Exposed Facility and an Experimental Logistics module. Canada will contribute the Mobile Servicing System robotic assembler/maintainer for the whole of SFF.

Kohrs, Richard H.↗

Potential use of tiltrotor aircraft in Canadian aviation

The aviation system in Canada is described as it relates to the potential applicability of tiltrotor technology. Commuter service in two corridors, the Vancouver-Victoria route on the west coast and the heavily traveled Montreal-Toronto corridor in eastern Canada, are examined. The operation of air service from the near-downtown Toronto STOLport and from the Vancouver-Victoria downtown heliport facilities is described. The emergency medical services, search and rescue, and natural resources development sectors are described with regard to the needs that tiltrotor technology could uniquely meet in these areas. The airport construction program in isolated communities of northern Quebec and possible tiltrotor service in northern regions are reviewed. The Federal and provincial governments' financial support policy regarding the aeronautical industry is to encourage the establishment and expansion of businesses in the field of aeronautics and to make possible the acquisition of new technology. This policy has implications for the tiltrotor program.

Gazdag, Denyse↗

Thermal balance testing of the Anik-E spacecraft

Spar Aerospace, Ltd. of Canada has recently completed the first of two infrared thermal balance/thermal vacuum tests on Canada's next generation of telecommunication satellites: Anik-E. Anik-E is a two spacecraft program using a three axis stabilized GE 5000 series bus as the vehicle for its payload. The infrared test setup consists of the mechanical hardware required to support the spacecraft within the thermal vacuum chamber and the infrared rig which supports the spacecraft. Spar developed a software package which calculated the lamp positions to provide the necessary uniform heat flux, based on the required heat inputs on the various isothermal zones of the spacecraft for the different phases of the tests. Infrared heat sensors, radiometers, were installed on the spacecraft surfaces. These were connected to the facility data processing system and continually monitored the flux absorbed by the various spacecraft surfaces. The test set up had distinct advantages. It enabled testing to progress directly from the thermal balance to thermal vacuum. Waveguide runs were installed for the communications portion of the testing prior to pumpdown. This precluded the requirement to return to ambient to reconfigure the setup.

Golob, Alex↗

Organic acids and selected nitrogen species for ABLE-3

The NASA Global Tropospheric Experiment (GTE) executed airborne science missions aboard the NASA Wallops Electra (NA429) in the North American high latitude (greater than 45 deg North) atmosphere during Jul. to Aug. 1988 and Jul. to Aug. 1990. These missions were part of GTE's Atmospheric Boundary Layer Experiment (ABLE). The 1988 mission , ABLE-3A, examined the ecosystems of Alaska as a source and/or sink for important tropospheric gases and particles, and gained new information on the chemical composition of the Arctic atmosphere during the summertime. During 1990 the second high latitude mission, ABLE-3B, focused on the Hudson Bay Lowland and Labrador regions of Canada. Both of these missions provided benchmark data sets on atmosphere biosphere exchange and atmospheric chemistry over largely uninhabited regions of North America. In support of the GTE/ABLE-3A and -3B field missions, the University of New Hampshire flew instrumentation aboard the Wallops Electra research aircraft to provide measurements of the trace gases nitric (HNO3), formic (HCOOH), and acetic (CH3COOH) acid. In addition, measurements were conducted to determine the major water soluble ionic composition of the atmospheric aerosol. For ABLE-3B, groundbased measurements of the acidic trace gases were also performed from the NASA micrometerological tower situated at Schefferville, Laborador. These measurements were aimed at assessing dry deposition of acidic gases to the taiga ecosystem in the Laborador region of Canada.

Talbot, Robert W.↗

Canadian MSAT field trial program user requirements

A wide range of mobile satellite service offerings will be available in late 1993 with the launch of Canada's first satellite devoted almost exclusively to mobile and transportable services. During the last seven years, the Dept. of Communications has been meeting with potential MSAT users in government and the private sector as part of a $20M Communications Trials Program. User trials will be conducted using leased capacity as well as capacity on Canada's MSAT satellite. User requirements are discussed which were identified under the Communications Trials Program. Land, marine, aeronautical, and fixed applications are described from the perspective of the end users. Emphasis is placed on field trials being accomplished using leased capacity such as the marine data trial being implemented by Ultimateast Data Communications, trials using transportable briefcase terminals and additional field trials being considered for implementation with the TMI Mobile Data Service. The pre-MSAT trials that will be conducted using leased capacity are only a limited sample of the overall end user requirements that have been identified to date. Additional end user applications are discussed, along with a summary of user benefits.

Pedersen, Allister↗

Multi-polarization C-band SAR for soil moisture estimation

Previous studies of synthetic aperture radar (SAR) imagery have shown qualitative relationships between radar backscatter and soil moisture. However, to be able to use these data in operational programs it will be necessary to establish quantitatively how the radar return is related to soil moisture and the effects of surface roughness, soil type, and vegetation cover and growth stage, as a function of frequency and polarization. To this end, a multi-year experiment began in 1990 as a cooperative venture amongst the Canada Center (Agriculture Canada), and the Universities of Guelph, Sherbrooke, Laval, and Waterloo. During 1990, SAR imagery was acquired during two periods (May and Jun.) to correspond to times of minimal and substantial vegetation cover. SAR data were acquired on three days in May and on four days in Jul. to cover different soil moisture conditions. This unique comprehensive data set is used to investigate the relationships between soil moisture and radar backscatter. The experiment and data collected are described, and a preliminary qualitative interpretation of the relationship between soil moisture and image tone is provided.

Brown, R. J.↗

Lidar Atmospheric Observatory in the Canadian Arctic

During the last decade there have been growing concerns about a broad variety of atmospheric properties. Among these, a depletion of the stratospheric ozone layer has attracted considerable attention from the general public, politicians and scientists due to its vital impact for the entire global biosphere. One of the major warning signs was the discovery of the 'ozone hole' in the Antarctic region where the concentration of the ozone in the stratosphere was significantly reduced. At present the stratospheric ozone layer in this region is being continuously monitored by groups of scientists from around the world and numerous observations of the ozone layer on the global scale have clearly demonstrated the process of ozone depletion. Recent observations by NASA have shown significant depletion in the Arctic region. This paper provides an initial description of two lidars that are planned to be installed in a new observatory for atmospheric studies in the Canadian Arctic. This observatory is being constructed under the supervision of the Atmospheric Environment Services (AES) of Canada as a part of Green Plan - an initiative of the Federal Government of Canada. The station is located at Eureka on Ellesmere Island at a latitude of 80 degrees N and a longitude of 86 degrees W.

Ulitsky, Arkady↗

SAR in support of geological investigations of the Sudbury structure

Imaging radar is an important contributing source of information for a range of geological problems and environments. Airborne SAR and ERS-1 data integrated with other geoscience datasets are being used in an attempt to characterize the crustal fracturing associated with the Sudbury structure. This presentation highlights examples of integrated and composite images aimed at facilitating the interpretation of the Sudbury structure. This work is the result of an ongoing cooperative multidisciplinary SAR study of the basin carried out by the Canada Center for Remote Sensing, Ontario's provincial Remote Sensing Office, the Ontario Geological Survey, and the Geological Survey of Canada.

Singhroy, V.↗

Status of the Olympus experiment at CRC

The status of the Olympus Propagation Experiment of the Communications Research Centre in Ottawa, Canada, is briefly summarized. Path attenuation measurements at multiple frequencies correlated with concurrent dual polarized radar data provide a unique method to investigate propagation effects. An experiment of this type is being implemented by the Communications Research Centre (CRC) on the grounds of the National Research Council of Canada in Ottawa. Beacon receivers monitor signals from the Olympus satellite at 12.5, 19.77, and 29.66 GHz at a path elevation angle of 14.2 deg. Sky noise radiometers operating near the same frequencies and pointed along the same path provide additional propagation information. A colocated dual-polarized 9.6-GHz radar probes the precipitation state on the path, permitting identification of precipitation regimes that cause the observed impairments. The Olympus experiment configuration is displayed pictorially. Information on path propagation phenomena can be deduced by correlating the radar, beacon, and sky noise data. Melting layer effects and propagation losses for higher time percentages are prime interests. Data collected by Diversitel Communications during equipment verification tests are presented.

Rogers, David V.↗

Effects of inorganic sulfur addition on fluxes of volatile sulfur compounds in Sphagnum peatlands

Short and long-term impacts of increased S deposition on fluxes of volatile S compounds (VSC's) from Sphagnum peatlands were investigated in an artificially acidified (sulfuric and nitric acids) poor fen (Mire 239) at the Experimental Lakes Area (ELA), Ontario, Canada. Additional experiments were conducted in a poor fen (Sallie's Fen) in Barrington, NH, USA. At Mire 239, emissions of VSC's were monitored, before and after acidification, at control (unacidified) and experimental sections within two major physiographic zones of the mire (oligotrophic and minerotrophic). The experimental segments of the mire received S amendments since 1983, in amounts equivalent to the annual S deposition in the highest polluted areas of Canada and U.S. Dimethyl sulfide (DMS) was the predominant VSC released from the mire and varied largely with time and space (i.e., from 2.5 to 127 nmol/m(sup -2)h(sup -1)). Sulfur addition did not affect DMS emissions in a period of hours to a few days, although it stimulated production of DMS and MSH in the anoxic surficial regions of the peat. DMS emissions in the experimental oligotrophic segment of the mire was approximately 3-fold greater than in the control oligotrophic segment, and approximately 10-fold greater than in the minerotrophic zones. These differences could be due to a combination of differences in types of vegetation, nutritional status, and S input. At Sallie's Fen, DMS fluxes were approximately 8 times higher from a Sphagnum site than from a bare peat site. Fluxes of VSC's were not significantly affected by sulfate amendments at both sites, while DMS and MSH concentrations increases greatly with time in the top 10 cm of the peat column. Our data indicated that although Sphagnum is not the direct source of DMS released from Sphagnum peatlands, it might play a role in regulating DMS emissions to the atmosphere.

Demello, William Zamboni↗

Flight service evaluation of composite components on the Bell helicopter model 206L

This is the final report on the advanced composite components which were placed in service on the 206L LongRanger helicopters in the continental United States, Canada, and Alaska. This report covers all test data which was gathered, as well as maintenance histories of the parts. The previous reports describe the fabrication, service experiences, and test data through 1986. This report contains information from these references, as well as data gathered after 1986. The status of the 40 sets of components is discussed. Each set consisted of a vertical fin, forward fairing, litter door, and baggage door. Almost 500,000 flight hours were accumulated on the 160 parts, with the high-time part accumulating 14,687 flight hours. Over 60 percent of the parts were destructively tested to measure strength and stiffness retention over the course of the program. The vertical fins had the greatest strength retention followed by the litter doors. The baggage doors had the poorest retention of strength. There was very little difference in property retention between the four primary operating regions: Northwest U.S., Southwest U.S., Gulf of Mexico Coastal Region, and the Northeast U.S. and Eastern Canada Region. The field problems have ranged from two lightning-struck fins to significant delaminations in the baggage doors. There was only one environmentally related field incident, in which the glass windows on the litter doors were found to loosen due to high temperatures experienced in the southwest region.

Wilson, Henry↗

ADS-33C related handling qualities research performed using the NRC Bell 205 airborne simulator

Over 10 years ago a project was initiated by the U.S. Army AVSCOM to update the military helicopter flying qualities specification MIL-8501-A. While not yet complete, the project reached a major milestone in 1989 with the publication of an Airworthiness Design Standard, ADS-33C. The 8501 update project initially set out to identify critical gaps in the requisite data base and then proceeded to fill them using a variety of directed research studies. The magnitude of the task required that it become an international effort: appropriate research studies were conducted in Germany, the UK and Canada as well as in the USA. Canadian participation was supported by the Department of National Defense (DND) through the Chief of Research and Development. Both ground based and in-flight simulation were used to study the defined areas and the Canadian Bell 205-A1 variable stability helicopter was used extensively as one of the primary research tools available for this effort. This paper reviews the involvement of the Flight Research Laboratory of the National Research Council of Canada in the update project, it describes the various experiments conducted on the Airborne Simulator, it notes significant results obtained and describes ongoing research associated with the project.

J Murray Morgan↗

A summary of microwave remote sensing investigations planned for BOREAS

The Boreal Ecosystem - Atmosphere Study (BOREAS) is a multidisciplinary field and remote sensing study that will be implemented jointly by the United States and Canada. The goal of BOREAS is to obtain an improved understanding of the interactions between the boreal forest biome and the atmosphere in order to clarify their roles in global change. Specific objectives are to improve the understanding of the processes that govern the exchanges of water, energy, heat, carbon, and trace gases between boreal ecosystems and the atmosphere, and to develop and validate remote sensing algorithms for transferring the understanding of these processes from local to regional scales. Two principal field sites, both within Canada, were selected. The northern site is located near Thompson, Manitoba, and the southern site encompasses Prince Albert National Park in Saskatchewan. The growing season in the northern site tends to be limited by growing-degree days while the southern site is limited by soil moisture and fire frequency. Most of the field work will occur at these two sites during 1993 and 1994 as part of six field campaigns. The first of these campaigns is scheduled for August 1993 and will involve instrument installation and an operational shakedown. Three large scale Intensive Field Campaigns (IFC's) are scheduled for 1994, along with two smaller scale Focused Field Campaigns (FFC's). The first 1994 campaign will be an FFC designed to capture the biome under completely frozen conditions during the winter. The second FFC and the first IFC are scheduled to capture the spring thaw period. Another IFC will take place in the summer during a period of maximum water stress. Finally, the third FFC will be scheduled to capture the collapse into senescence during the fall.

Mcdonald, Kyle C.↗

An innovative approach to space education

At present, Canada does not have enough scientists to be competitive in the global economy, which is rapidly changing from a reliance on natural resources and industry to information and technology. Space is the final frontier and it is a multidisciplinary endeavor. It requires a knowledge of science and math, as well as non-science areas such as architecture and law. Thus, it can attract a large number of students with a diverse range of interests and career goals. An overview is presented of the space education program designed by Canadian Alumni of the International Space University (CAISU) to encourage students to pursue studies and careers in science and technology and to improve science literacy in Canada.

Marton, Christine↗

Tropospheric ozone and aerosol variability observed at high latitudes with an airborne lidar

Large-scale summertime (July-August) distributions of O3 and aerosols were observed in a broad range of atmosphere conditions over the tundra, ice, and ocean regions near Alaska in 1988 and over the lowlands and boreal forests of Canada in 1990. The tropospheric O3 budget in the high-latitude regions was found to be strongly influenced by stratospheric intrusions, and deposition at the surface was found to be the main sink for O3 in the troposphere. Enhanced levels of O3 were observed in plumes from fires in Alaska and Canada. This paper discusses the large-scale variability of O3 and aerosols observed in the high-latitude regions during these field experiments.

Browell, Edward V.↗

Visible light nitrogen dioxide spectrophotometer intercomparison: Mount Kobau, British Columbia, July 28 to August 10, 1991

Under the auspices of the World Meteorological Organization, Environment Canada hosted an international comparison of visible light spectrophotometers at Mt. Kobau, British Columbia in August of 1991. Instruments from four countries were involved. The intercomparison results have indicated that some significant differences exist in the responses of the various instruments, and have provided a basis for the comparison of the historical data sets which currently exist as a result of the independent researches carried out in the past in the former Soviet Union, New Zealand, and Canada.

Mcelroy, C. T.↗

The 1991 WMO ozone sonde intercomparison

The WMO ozone sonde intercomparison was held at Vanscoy, Saskatchewan from May 13 to May 24, 1991. The purpose of the intercomparison is to evaluate the performance of various ozone sonde types used operationally in the Global Ozone Observing System and to ensure that the accuracy and precision of the measurements are sufficient to detect long-term trends in stratospheric ozone. The intercomparison was sponsored by WMO and hosted by the Atmospheric Environment Service (AES) of Canada. It was attended by scientists from six countries: Canada, Finland, Germany, India, Japan and USA. A total of 10 balloon payloads were launched each carrying 7 or 8 sondes for a total of 67 successful ozone sonde flights. The payloads were carried to altitudes between 35 and 40 km where the flights terminated by balloon burst. Results of the profile measurements made during the series of the profile measurements made during the series of flight are used to determine statistically meaningful evaluations of the different sonde types. A description of the payload and the different ozone sondes is given. Preliminary results of the profile measurements and an evaluation of the performance of the sonde types are presented.

Kerr, James B.↗

Compendium of NASA data base for the Global Tropospheric Experiment's Arctic Boundary Layer Experiments ABLE-3A and ABLE-3B

The report provides a compendium of NASA aircraft data that are available from NASA's Global Tropospheric Experiment's (GTE) Arctic Boundary Layer Experiments (ABLE) conducted in July and August of 1988 (ABLE-3A) and 1990 (ABLE-3B). ABLE-3A flight experiments were based at Barrow and Bethel, Alaska, and included survey/transit flights to Thule, Greenland. ABLE-3B flight experiments were based at North Bay (Ontario) and Goose Bay, Canada, and included flights northward to Frobisher Bay, Canada. The primary purposes of the experiments were (1) the measurement of the flux of various trace gases from high-arctic ecosystems, (2) the elucidation of factors important to the production and destruction of ozone, and (3) the documentation of source and chemical signature of air common to and transported into the regions. The report provides a representation, in the form of selected data plots, of aircraft data that are available in archived format via NASA Langley's Distributed Active Archive Center. The archived data bases include data for other species measured on the aircraft as well as numerous supporting data, including meteorological observations/products, results from surface studies, satellite observations, and sondes releases.

Gregory, Gerald L.↗