Neural [correction of Neutral] networks for control, identification and diagnosis.

Advances in the theory and technology of artificial neural networks provide the potential for new approaches to the problems of control, identification, and diagnosis for large, complex systems. However, these approaches must be validated for specific applications before they can be exploited effectively. Because of the unique capabilities they offer, neural networks should play an important role in space exploration systems operations. After a brief introduction to neural networks is presented, some applications of neural networks to identification and control of space systems are described and discussed. They span the spectrum of relatively straightforward to rather complex applications. An explanation of how neural networks can be applied to such important tasks as fault diagnosis and accommodation is presented. Neural networks are shown to be part of the hierarchy of intelligent control where a higher order decision element monitors and supervises lower order elements for sensing and actuation.     

Radiation effects on late cytopathological parameters in the murine lens relative to particle fluence.

Lenses of mice irradiated with 250 MeV protons, 670 MeV/amu 20Ne, 600 MeV/amu 56Fe, 600 MeV/amu 93Nb and 593 MeV/amu 139La ions were evaluated by analyzing cytopathological indicators which have been implicated in the cataractogenic process. The LETs ranged from 0.40 keV/micrometer to 953 keV/micrometer and fluences from 1.31 10(3)/mm2 to 4.99 x 10(7)/mm2. 60Co gamma-rays were used as the reference radiation. The doses ranged from 10 to 40 cGy. The lenses were assessed 64 weeks post irradiation in order to observe the late effects of LET and dose on the target cell population of the lens epithelium. Our study shows that growth dependent pathological changes occur at the cellular level as a function of dose and LET. The shapes of the RBE-LET and RBE-dose curves are consistent with previous work on eye and other biological systems done in both our laboratory and others. The RBEmax's were estimated, for the most radiation cataract related cytological changes, MN frequency and MR disorganization, by calculating the ratio of the initial slopes of dose effect curve for various heavy ions to that of 60Co gamma-ray. For each ion studied, the RBEmax derived from micronucleus (MN) frequency is similar to that derived from meridional row (MR) disorganization, suggesting that heavy ions are equally efficient at producing each type of damage. Furthermore, on a per particle basis (particle/cell nucleus), both MN frequency and MR disorganization are LET dependent indicating that these classic precataractogenic indicators are multi-gene effects. Poisson probability analysis of the particle number traversing cell nuclei (average area = 24 micrometers2) suggested that single nuclear traversals determine these changes. By virtue of their precataractogenic nature the data on these endpoints intimate that radiation cataract may also be the consequence of single hits. In any case, these observations are consistent with the current theory of the mechanism of radiation cataractogenesis, which proposes that genomic damage to the epithelial cells surviving the exposure is responsible for opacification.     

Future fighter fable: a day in the life of a future fighter-how dowe get there from here?

The intent of this tongue-in-cheek paper is to stimulate thought about technologies that may be included in future weapons systems and how the weapon system developer is impacted today. It explores a day in the life of a future generation fighter aircraft (year 2015-2025 time-frame). The scenario starts from the perspective of the ground crew awaiting the return of their future fighters: the new A/F-2, “Thunderchief II”-to a dispersed operations location (DOL) from a combat air patrol (CAP) mission in the fictitious country of Crad. A nonrestrictive technology view is assumed, tempered with as much realism as one can logically include in the scenario, with some of today's evolving technology thrusts     

Application of numerical Fourier transformation on measurements made on board rotating spacecrafts

Signals obtained on board rocket payloads or satellites are often “spin modulated”. The relevant information is then found within the envelope and the phase of the signal. The most efficient method of extracting this information is the numerical Fourier analysis.     

Interannual variability

The new Reference Atmosphere presented here is based on global satellite data and forms a very useful basis for climatological studies. When using such climatologies it is important to be aware of the well known interannual variability which in the middle atmosphere is particularly large during the northern winters and southern springs.     

Interface and usability assessment of imaging systems

This paper discusses a plan for collecting critical information about the interface, usability, and the efficiency and effectiveness of two imaging systems: Rapiscan's Secure 1000 and American Science & Engineering's Body Search; both systems use backscatter technology.     

The solar orbiter mission

Approved in October 2000 by ESA's Science Programme Committee as a flexi-mission, the Solar Orbiter will studythe Sun and unexplored regions of the inner heliosphere from a unique orbit that brings the probe to within 45 solar radii (0.21 AU) of our star, and to solar latitudes as high as 38°. This orbit will allow the Solar Orbiter to make fundamental contributions to our understanding of the acceleration and propagation of energetic particles in the extended solar atmosphere. During quasi-heliosynchronous phases of the orbit, Solar Orbiter will track a given region of the solar surface for several days, making possible unprecedented studies of the sources of impulsive and CME-related particle events. The scientific payload to be carried by the probe will include a sophisticated remote-sensing package, as well as state-of-the-art in-situ instruments. The multi-wavelength, multi-disciplinary approach of Solar Orbiter, combined with its novel location, represents a powerful tool for studies of energetic particle phenomena.