Analyses of exobiological and potential resource materials in the Martian soil.

Potential Martian soil components relevant to exobiology include water, organic matter, evaporites, clays, and oxides. These materials are also resources for human expeditions to Mars. When found in particular combinations, some of these materials constitute diagnostic paleobiomarker suites, allowing insight to be gained into the probability of life originating on Mars. Critically important to exobiology is the method of data analysis and data interpretation. To that end we are investigating methods of analysis of potential biomarker and paleobiomarker compounds and resource materials in soils and rocks pertinent to Martian geology. Differential thermal analysis coupled with gas chromatography is shown to be a highly useful analytical technique for detecting this wide and complex variety of materials.     

A method for improving extended Kalman filter performance forangle-only passive ranging

A relatively simple method is presented which eliminates previously reported (Oct. 1985) erratic estimation performance associated with Cartesian formulations of the extended Kalman filter (EKF) for the 2D angle-only emitter location problem. The technique is based on an initialization procedure which combines a priori probability density function (pdf) information with single measurement a posteriori pdf information in a manner which is more efficient than the EKF. Simulation results are presented which demonstrate the utility of the technique as compared with a previously offered modified gain EKF     

The Electron Beam Instrument (F6) on Freja

The Electron Beam Instrument (F6) onFreja is the first attempt to apply the electron drift technique in a region of large ambient magnetic fields. The paper describes the operational principles, the technical realization, and the difficulties encountered in the derivation of the electric fields.     

Stellar infrared astronomy with EDISON

In this review the IR emission from circumstellar material is discussed, both of ionized gas and dust grains, and the astrophysical information that can be extracted from such observations. Some emphasis is placed on the possibilities of stellar IR astronomy using a large space-borne telescope, especially with respect to the much better spatial and spectral resolution of such a telescope compared to the current generation of ground-based and space IR telescopes.     

Field formation around negatively biased solar arrays in the LEO-plasma

Heavy emission caused by impacting plasma ions results in a fast discharging effect of the initially large surface potentials on the dielectric solar cells. This eventually counteracts the energization process of the plasma ions to the cover glasses and leaves no significant electric fields. Thus, with an existing thermal plasma, electrons are again able to reach dielectric surfaces. Strong localized electric fields of the order of several 10 kV/cm form near the interconnector-cover glass interface.     

Charging the new batteries-IC controllers track new technologies

Demands for portability have fueled significant developments in new battery technology. These developments have resulted in many more options in selecting the battery type for use in a particular project, but since most applications today are opting for rechargeable battery systems, the availability of battery charging solutions can become an equally important criteria in the selection process. Complicating this process are the demands for fast-but safe-charging with charge algorithms easily implemented with low-cost hardware. With the higher levels of complexity attendant with these more demanding algorithms, solutions have come primarily from the integrated circuit industry and the purpose of this paper is to provide a few examples of the latest efforts in this arena, specifically as addressed to lead-acid, nickel metal-hydride, and lithium-ion technologies     

Trunking vs. conventional radio systems

Correctional Service Canada (CSC) has recently replaced the aging, out-of-date radio communications systems in all major CSC facilities with new conventional digital radio systems. Based on very specific and restrictive operational requirements coupled with developments in digital radio technology and the Associated Public Communications Officers (APCO) Project 25 digital radio standards, it was determined that digital radio communications would best meet CSC's needs. The CSC national radio replacement program was completed in March 2000. Switching to a digital radio communications system gave CSC an opportunity to consider changing the existing radio system from a number of conventional, single-site systems to a trunking system. Areas to be considered when determining the architecture for a radio communication network, whether radio trunking systems or conventional radio systems should be used, are presented, In addition, the paper will also outline the requirements and measures taken to keep the radio communication network active and operational while the equipment was converted from an analog technology to a digital one     

Lower and upper limits to comet p/halley solid material loss rate

A radiative hydrodynamic model of comet P/Halley is used to investigate quantitatively the constraints imposed onto the Comet loss rate in solids by both the in-situ data and the remote sensing data. In particular, for the first time, the in-situ data are used to fit composite spectra extending from near-IR wavelengths to the microwave region. Also, for the first time the uncertainty affecting the ejection velocity of large grains is taken into account. The results suggest that only future rendez-vous studies of the grain density in the vicinity of a comet would be able to provide definitely reliable values of the comet loss rate.