Performance Analysis of the Modulation Cancellation Altimeter

The performance of the modulation cancellation altimeter is investigated. Several sources of error are considered, specifically: 1) terrain averaging error; 2) output noise fluctuations; 3) errors due to phase shifts; and 4) acquisition ambiguities. The predominant parameters affecting these errors are investigated with a view towards optimizing the performance of the altimeter.     

Bars — A dual bistatic auroral radar system for the study of electric fields in the Canadian sector of the auroral zone

One instrument of the Canadian Auroral Network for the Open Program Unified Study (CANOPUS) is a pulsed dual bistatic auroral radar system (BARS) for the mapping of ionospheric electric fields, using the STARE technique originated by R.A. Greenwald [14]. The Canadian system is presently in the specification and design phases, with the objective of being operational by mid-1984. This paper describes the geometry of the BARS system, the design considerations, and the planned data and control network.     

The failure of marginal detonations in expanding channels

Critical conditions for detonation failure due to tube expansion have been observed in marginal detonations propagating in a in. (6.35 × 76.2 mm) channel. In these experiments, a well established marginal detonation propagating in the narrow channel entered a test section in which one of the narrow walls was inclined to the central axis at positive angles which ranged from 10° to 45°. Experiments were performed at pressures ranging from 60 to 200 torr (8 to 26.7 kPa) in stoichiometric hydrogen-oxygen mixtures diluted with 20, 50 and 70% argon. Smoke track records obtained on the surface which is the major dimension of the tube, were used to determine failure, incipient failure or self-sustenance of the entering wave.Because of the narrow tube used in the studies the incident waves were marginal in that their velocity was below the expected CJ (Chapman-Jouguet) value, their transverse wave spacing was larger than one would see in a large tube, and the transverse waves were of greater strength than in an ordinary detonation. All of these indicators of marginal behavior became progressively more pronounced as the pressure dropped from 200 torr (26.7 kPa) to the limit pressure of approximately 58 torr (7.73 kPa).The most interesting result of this experimental investigation is that the theoretical analyses predicted that simple one-dimensional opening of the tube should not show a pressure dependence to failure, while the experiments showed a definite decrease in the opening angle required for failure as initial pressure decreased. This behavior is related to the marginality of the incident waves, which is observed to increase smoothly with decreased pressure. It is postulated that detonation failure in the hydrogen-oxygen system occurs when the shock velocity at the end of the cell drops to about 0.60 of the CJ value due either to marginal behavior or to an expansion of the cross section of the tube.     

Superclustering and the large-scale structure of the universe

The spatial distribution of a complete redshift sample of nearby rich clusters of galaxies is studied. Strong superclustering, extending to very large scales (100h⁻¹Mpc), is observed in the cluster distribution. In particular, we determined and discuss below the following studies:I. The spatial correlation function of rich clusters of galaxies.II. The construction of a complete catalog of superclusters and a study of their growth (percolation).III. The finding of large-scale superclusters surrounding the giant galaxy void in Bootes.IV. The finding of a 300 Mpc void of rich clusters of galaxies.All the above studies provide evidence for the existence of large-scale structure in the universe, and reveal some of its characteristics. These findings are of importance to models of the formation of galaxies and structure in the universe.     

Scientific results from the pioneer Saturn infrared radiometer

The Pioneer 11 Infrared Radiometer instrument made observations of Saturn and its rings in broadband channels centered at 20 and 45 μm and obtained whole-disk information on Titan. A planetary average effective temperature of 96.5±2.5 K implies a total emission 2.8 times the absorbed sunlight. Correlation with radio science results implies that the molar fraction of H₂ is 90±3% (assuming the rest is He). Temperatures at the 1 bar level are 137 to 140 K; regions appearing cooler may be overlain by a cloud acting as a 124 K blackbody surface. A minimum temperature averaging 87 K is reached near 0.06 bars. Ring boundaries and optical depths are consistent with those at optical wavelengths. Ring temperatures are 64–86 K on the south (illuminated) side, ～54 K on the north (unilluminated) side, and at least 67 K in Saturn's shadow. There is evidence for a south to north drop in ring temperatures. Titan's 45 μm brightness temperature is 75±5 K.     

Dynamic imaging and RCS measurements of aircraft

Results on radar cross section (RCS) measurements and inverse synthetic aperture radar images of a Mooney 231 aircraft using a ground-to-air measurement system (GTAMS) and a KC-135 airplane using an airborne radar are presented. The Mooney 231 flew in a controlled path in both clockwise and counterclockwise orbits, and successively with the gear down, flaps in the take-off position and with the speed brakes up. The data indicates that RCS pattern measurements from both ground-based and airborne radar of flying aircraft are useful and that the inverse synthetic aperture radar (ISAR) images obtained are valuable for signature diagnostics     

Electrical power on a 30 kW space-based radar satellite

An electrical power system for a space-based radar satellite is described. When the radar is on, its transmitter needs an average DC power of 30 kW. The problem of distributing the power efficiently in pulses to many transmit/receive modules is addressed. System requirements include a high-voltage battery and transmission line, load-sharing between the solar array, and the battery during sunlit periods, and a 25-kW solar array. A scaled-down version of the power system for a proof-of-concept demonstration is described     

Determination of orbits with Torun Orbit Processor system

The Torun Orbit Processor system (TOP) is a multipurpose system designed to provide the research requirements of the various orbital problems for artificial satellites. The analysis of mathematical model for the TOP system began in 1991 and coding for the IBM PC and Sun SparcStation 10 computers was completed in 1993. TOP was first used for laser data processing of Lageos satellite and for simulations of satellite-to-satellite tracking technique (SST). This paper gives an overview of TOP system and highlights some problems connected with orbit recovery.     

Some aspects of the early evolution of photosynthesis.

The early evolution of a photocatalytic system of the porphyrin type, able to efficiently collect and utilize solar energy for primary electron transfer is discussed. Experimental results concerning some spectral and photochemical properties of the porphyrins, biosynthetic precursors of chlorophyll and their complexes with polymeric templates are reviewed. Protoporphyrin IX associated with pigmented proteinoid is demonstrated to be a favourable candidate for a role of a photosensitizer of the first photosynthetic reaction centers. The origin and early evolution of the photosynthetic electron transfer chain and of the phosphorylating mechanism are discussed with emphasis on the energetic mechanisms of archaebacteria.