Canada's early space policy development 1958–1974

In the absence of a mature body of literature on the origins and evolution of the Canadian space program, recent official publications have arbitrarily chosen 1974, the year that Canada's civilian space policy was ratified in the House of Commons, as the popular date of origin. However, this start date ignores several significant policy documents that influenced Canada's space program development prior to that year. This article examines policy that shaped Canada's space program during the ‘golden age’ of space exploration (1958–1974), and will demonstrate that the true origins of the Canadian space program date back much earlier that the current perception.     

I: PRECISE ORBIT DETERMINATION AND GRAVITY FIELD MODELLING: Strategies for Precise Orbit Determination of Low Earth Orbiters Using the GPS

Considerable experience accumulated during the past decade in strategies for processing GPS data from ground-based geodetic receivers. First experience on the use of GPS observations from spaceborne receivers for orbit determination of satellites on low altitude orbits was gained with the launch of TOPEX/POSEIDON ten years ago. The launch of the CHAMP satellite in July 2000 stimulated a number of activities worldwide on improving the strategies and algorithms for orbit determination for Low Earth Orbiters (LEOs) using the GPS. Similar strategies as for ground-based receivers are applied to data from spaceborne GPS receivers to determine high precision orbits. Zero- and double-differencing techniques are applied to obtain kinematic and/or reduced-dynamic orbits with an accuracy which is today at the decimeter level. Further developments in modeling and processing strategies will continuously improve the quality of GPS-derived LEO orbits in the near future. A significant improvement can be expected from fixing double-difference phase ambiguities to integer numbers. Particular studies focus on the impact of a combined processing of LEO and GPS orbits on the quality of orbits and the reference frame realization. This revised version was published online in August 2006 with corrections to the Cover Date.     

Full-polarization matched-illumination for target detection and identification

This paper investigates the optimization of the full-polarization radar transmission waveform and the receiver response to maximize either target detection or identification performance. Application of such full-polarization matched-illumination techniques to simulated VHF-band frequency response data of mobile surface targets yields a significant performance improvement over that corresponding to chirped full-polarization transmission waveforms.     

Modified gradiometer technique applied to Double Star (TC-1)

On TC-1 (Tan Ce 1), the equatorial spacecraft of the Double Star mission, a strong spin-synchronized magnetic interference from the solar panels was observed. In-flight correction techniques for spinning spacecraft that are based on minimizing spin tones in the spin-aligned component and in the magnitude of the ambient magnetic field are therefore not possible in this case. However, due to the fortunate situation that the spacecraft carries two flux-gate magnetometers on the same boom (at 0.5 m distance from each other), the spacecraft field effects could be removed from the spin-averaged data to achieve 0.2 nT relative accuracy, by using a gradiometer technique. Methodology and results are presented. The obtained accuracy allows the use of the data in multi-spacecraft studies together with the Cluster satellites.     

Simulated cometary matter as a test for enantiomer separating chromatography for use on comet 46P/Wirtanen.

The Cometary Sampling and Composition Experiment on board of European Space Agency's cornerstone mission ROSETTA is designed to identify organic molecules in cometary matter in situ by a combined pyrolysis gas chromatographic and mass spectrometric technique. Its capillary columns coated with chiral stationary phases received considerable attention, because they are designed for separations of non-complex enantiomers to allow the determination of enantiomeric ratios of cometary chiral organic compounds and consequently to provide information about the origin of molecular parity violation in biomolecules. To get gas chromatographic access to organic compounds on the comet, where macromolecules and complex organic polymers of low volatility are expected to make up the main organic ingredients, the combination of two injection techniques will be applied. The pyrolysis technique performed by heating cometary samples stepwise to defined temperatures in specific ovens resulting in thermochemolysis reactions of polymers and a chemical derivatization technique, in which the reagent dimethylformamide dimethylacetal assists pyrolysis derivatization reactions in producing methyl esters of polar monomers. The combination of the reagent assisted pyrolysis gas chromatographic technique with enantiomer separating chromatography was tested with laboratory-produced simulated cometary matter.     

Depeaking – economic optimization of air traffic systems

More than half of all flights in and out of Frankfurt International Airport are conducted by Lufthansa airlines, as it is one of their two major hubs. The so called hub and spokes systems allow airlines to bundle major passenger flows via connecting flights across the in- and outbound traffic. The reliability of these transfer connections, and specifically the arrival punctuality at the hub airports are crucial to the economics of the daily operation.Since Frankfurt International Airport has lately been one of the most congested airports in Europe, delays (in particular arrival delays) have increased quite significantly throughout the last years. To compensate for additional queueing time in the arrival processes, the scheduled block times inbound Frankfurt were continuously adjusted upwardly keeping the arrival punctuality (and thereby the connection reliability) close to stable. The two disadvantages of this approach have been the decrease in aircraft productivity and over-deliveries in peak hours, which in turn induce either additional block time delay or ground delay programs inbound Frankfurt.This paper introduces an iterative stochastic-simulation approach that models the vicious circle of lengthening block times and increased over-deliveries. In a second step it quantifies the operational and economical effects of depeaking the schedule and illustrates the overall growth potentials for the depeaked operation of the airport. The schedule was successfully implemented in Frankfurt in summer 2004.     

新型风扇整流罩设计

古德里奇公司与庞巴迪航宇公司共同为V2500-A5发动机短舱开发了一种新型风扇整流罩,可以减轻发动机重量及维修成本.2008年初秋,该项目获得了FAA颁发的补充型号认证(STC).     

Non-Gaussian clutter characterization applied to OTHR using a mixture of two Rayleigh probability density functions

A practical technique for characterizing non-Gaussian radar clutter is specified and demonstrated using Over The Horizon Radar (OTHR) data, as an example. The technique employs maximum likelihood to fit the probability density of the clutter amplitude returns to a mixture of two Rayleigh probability densities instead of the single Rayleigh density typically used for Gaussian clutter. This model for non-Gaussian clutter is fully specified for any set of clutter amplitudes by a log likelihood, two Rayleigh parameters, and a mixing coefficient. A 3D plot of these values yields an easily-visualized clutter characterization, as is illustrated using OTHR data. This technique is a demonstration of clutter characterization using OTHR data, but the method can be applied to characterize other types of clutter data.