A technique and diagnostic aids of diesel engine fuel equipment in service conditions

In this paper, a number of general approaches to the vibration diagnostics of diesel engine fuel equipment (including that of aircraft ones) is considered. Based on the corresponding analysis, the approach and particular techniques of vibration diagnostics under operating conditions (without dismantling the fuel equipment on the object to be examined) are presented.     

A glimpse from the inside of a space suit: What is it really like to train for an EVA?

The beauty of the view from the office of a spacewalking astronaut gives the impression of simplicity, but few beyond the astronauts, and those who train them, know what it really takes to get there. Extravehicular Activity (EVA) training is an intense process that utilizes NASA’s Neutral Buoyancy Laboratory (NBL) to develop a very specific skill set needed to safely construct and maintain the orbiting International Space Station. To qualify for flight assignments, astronauts must demonstrate the ability to work safely and efficiently in the physically demanding environment of the space suit, possess an acute ability to resolve unforeseen problems, and implement proper tool protocols to ensure no tools will be lost in space. Through the insights and the lessons learned by actual EVA astronauts and EVA instructors, this paper will take you on a journey through an astronaut’s earliest experiences working in the space suit, termed the Extravehicular Mobility Unit (EMU), in the underwater training environment of the NBL. This work details an actual Suit Qualification NBL training event, outlines the numerous challenges the astronauts face throughout their initial training, and the various ways they adapt their own abilities to overcome them. The goal of this paper is to give everyone a small glimpse into what it is really like to work in a space suit.     

Calculation of resultant vector and principal moment of light pressure forces acting upon the spacecraft with a solar sail

Two methods of calculating the resultant vector and principal moment of light pressure forces, having an effect on a spacecraft with a composite solar sail, are compared. The first method is based on analytical formulas obtained without regard to shading of some parts of the sail by others. The second method uses a detailed geometrical model of the sail, which allows one to take such shading into account. Some part of photons falling on a sail is supposed to be reflected from it in a mirror manner, while the others are completely absorbed. The range of variation of sail orientation parameters with respect to incident solar light streams, where the first method turns out to be accurate enough, is found.     

Omnidirectional integrated helicopter air data system based on the stationary multichannel aerometric transducer

In this paper, a problem of measuring the altitude-speed helicopter performance in the range of low and near-zero flight velocities is considered. The structural functional scheme of the omnidirectional helicopter air data system based on the stationary aerometric multichannel transducer (AMT) as well as the jet-convective measuring channels is shown and algorithms for the formation of the system output signals are presented. In order to extend the lower bound of operating speeds, it is proposed that the omnidirectional system be integrated with the aeromechanical measuring computer system that realizes the VIMI method with Luenberger’s observer. Also given is the algorithm support and the accuracy of the integrated system operation is estimated.     

Propulsion of space ships by nuclear explosion

Recent progress in the research on deuterium-tritium (D-T) inertially confined microexplosions encourages one to reconsider the nuclear propulsion of spaceships based on the concept originally proposed in the Orion project. We discuss first the acceleration of medium-sized spaceships by D-T explosions whose output is in the range of 0.1–10 t of TNT. The launching of such a ship into an Earth orbit or beyond by a large nuclear explosion in an underground cavity is sketched out in the second section of the paper, and finally we consider a hypothetical Mars mission based on these concepts. In the conclusion it is argued that propulsion based on the Orion concept only is not the best method for interplanetary travel owing to the very large number of nuclear explosion required. A combination of a super gun and subsequent rocket propulsion using advanced chemical fuels appears to be the best solution for space flights of the near future.From Kosmicheskie Issledovaniya, Vol. 43, No. 1, 2005, pp. 67–75.Original English Text Copyright © 2005 by Linhart, Kravárik.     

Ultrastructural aspects of otoliths and sensory epithelia of fish inner ear exposed to hypergravity.

The present electron microscopical investigations were directed to the question, whether alterations in the gravitational force might induce structural changes in the morphology of otoliths or/and inner ear sensory epithelia of developing and adult swordtail fish (Xiphophorus helleri) that had been kept either under long-term moderate hypergravity (8 days; 3g) or under short-time extreme hypergravity (10 minutes up to 9g). The otoliths of adult and neonate swordtail fish were investigated by means of scanning electron microscopy (SEM). Macular epithelia of adult fish were examined both by SEM and transmission electron microscopy (TEM). The saccular otoliths (sagittae) of normally hatched adult fish revealed an enormous inter- (and even intra-; i.e. left vs. right) individual diversity in shape and size, whereas the otoliths of utricles (lapilli) and lagenae (asterisci) seemed to be more constant regarding morphological parameters. The structural diversity of juvenile otoliths was found to be less prominent as compared to the adults, differing from the latter regarding their peculiar crystalline morphology. Qualitative differences in the fine structure (SEM) of otoliths taken from adult and larval animals kept under 3g in comparison to 1g controls could not be observed. The SEM and TEM investigations of sensory epithelia also did not reveal any effects due to 3g stimulation. Even extreme hypergravity (more than 7g) for 10 minutes did not result in distinct pathological changes.     

The atmospheric cosmic- and solar energetic particle radiation environment at aircraft altitudes

Galactic cosmic rays interact with the solar wind, the earth's magnetic field and its atmosphere to produce hadron, lepton and photon fields at aircraft altitudes. In addition to cosmic rays, energetic particles generated by solar activity bombard the earth from time to time. These particles, while less energetic than cosmic rays, also produce radiation fields at aircraft altitudes which have qualitatively the same properties as atmospheric cosmic rays. We have used a code based on transport theory to calculate atmospheric cosmic-ray quantities and compared them with experimental data. Agreement with these data is seen to be good. We have then used this code to calculate equivalent doses to aircraft crews. We have also used the code to calculate radiation doses from several large solar energetic particle events which took place in 1989, including the very large event that occurred on September 29^th and 30^th of that year. The spectra incident on the atmosphere were determined assuming diffusive shock theory.     

Influence of clinorotation and fettering stress on tail regeneration of Triturus vulgaris (Urodela).

Tail-amputated adult Triturus vulgaris, fettered in cuvettes of a fast-rotating clinostat were exposed to simulated weightlessness (60 rpm; equiv. to 10(-3)-10(-4) g), during a 14-day period. To feed and clean the animals rotation was stopped once a day for approx. 10 min. To test the influence of the fettering stress, a second series of animals was kept separately under normal earth conditions without rotation. A further control series was kept in a dark container without any handicap. While tail regeneration of the rotated animals was markedly accelerated, the fettered-only animals showed a considerably less marked acceleration effect. At the end of the 14-day period, all regenerates were reamputated together with an additional 5 mm of the tail stump. Although this second level of amputation was distant from the first, the regenerative growth rate of the rotated series was accelerated 123% in contrast to both the control and the fettered-only series. Our results demonstrate that the growth acceleration is induced by clinorotation. Fettering stress has no comparable influence. The growth promoting effect is not limited to the regenerating area.     

Development of simultaneous imaging polarimeter for asteroids

We are currently developing a polarimeter to study surface physical properties of asteroids. To enhance polarimetric accuracy and observational efficiency, we newly devised the polarimeter whose measurements can provide the two Stokes parameters Q and U, simultaneously. The test-observations of the prototype polarimeter have been carried out in December 2003 and January 2004, mounted on the 101 cm telescope at Bisei Astronomical Observatory, Okayama, Japan. In the observations, unpolarized and polarized standard stars were observed to measure an instrumental polarization and its uncertainty. As a result, an instrumental polarization of 5.06 ± 0.18% has been measured.