High-acceleration mass drivers

After testing an early, simplified mass-driver (35 gravity acceleration) a second, designated MD2, was designed and is now operating. MD2 is of axial geometry, with individually powered drive coils of 13.1 cm diameter. Timing is derived through the interruption of light beams by the moving armature (bucket). Electric power is provided by the resonant discharge of sector capacitor banks through silicon-controlled rectifiers in a two-phase, quadrature circuit. The bucket flies in vacuum, guided by passive dynamic eddy-current magnetic forces, those currents flowing in strip conductors lining the inside of a nonconducting vacuum pipe. The initial length of MD2 is 2.5 m, divided equally into acceleration and deceleration. Nominal acceleration is 5000 m/sec². For routine testing an ohmic bucket is used. Quantitative measurements are obtained with a solid bucket carrying two superconducting coils with a current density of 25 kA/cm². A cryogenic station for cooling the bucket to liquid helium temperature is connected to the vacuum pipe. The test program, now begun, will concentrate on guidance and acceleration forces, measurement of drive shielding losses, and possible couplings of drive forces into modes of oscillation.     

Current views and future programs in cardiovascular physiology in space.

The volume shift of 2000 cm3 from the lower to the upper part of the human body during weightlessness gave rise to theoretical and practical questions which are addressed in this communication. The analysis revealed that the mobilized fluid reduced the interstitial fluid of the lower extremities by 40%. Applying the current ideas in the field of interstitial tissue physiology to these problems, one must conclude that the fluid displacement can only be brought about by a change of the interstitial tissue compliance. Based on the observations made by the astronauts and on our working hypothesis, a method was proposed to follow the fluid migration and to measure the tissue compliance in man. Results are reported from experiments under terrestrial conditions. They show that the tissue compliance indeed can be modulated. Applying the method in space can eventually help to clarify several concepts in terrestrial physiology.     

STADAR: Servo Tester with Automatic Data Acquisition and Reduction

STADAR is a Servo Tester with Automatic Data Acquisition and Reduction developed for the Apollo program. This paper describes the operational capability of STADAR and discusses certain aspects of the design. STADAR evaluates system performance by supplying an input stimuli and two data acquisition and analysis channels. Stimuli (0.02-30 c/s 0-10 V peak) are automatically programmed to a frequency accuracy of ±0.01 percent and an amplitude accuracy of ± 0.1 percent. Data acquisition accuracy is 0.1 percent or 50 microvolts. System design utilizes programmable data filters to improve system S/N ratio. Active filter mechanization methods and results are presented as well as techniques for instantaneous precise generation of stimuli which are automatically programmed.     

Solution numérique du problème de Képler

A numerical solution of the Kepler problem. Requiring a six-decimal accuracy, the Kepler problem can be solved with four iterations at most, even for an eccentricity close to 1, provided that a new initial approximation be introduced in this last case.     

The reactions of nitrogen heterocycles with acrolein: scope and prebiotic significance

It has been suggested that life began with a self-replicating RNA molecule. However, after much research into the prebiotic synthesis of RNA, the difficulties encountered have lead some to hypothesize that RNA was preceded by a simpler molecule, one more easily synthesized prebiotically. Many of the proposed alternative molecules are based on acrolein, since it reacts readily with nucleophiles, such as the nucleobases, via Michael addition and is readily synthesized from formaldehyde and acetaldehyde. Reports regarding the reactions of nucleobases with concentrated acrolein solutions suggest that this is a plausible reaction mechanism, though there are also reports that the "incorrect" isomers are obtained. The scope and kinetics of the reaction of acrolein with various nitrogen heterocycles are reported here. Reactions of pyrimidines often give N(1) adducts as the major products. Reactions of purines often give N(9) adducts in good yield. The reactions are rapid under neutral to slightly alkaline conditions, and proceed at low temperatures and dilutions. The implications of these findings for the origin of life are discussed.     

A methodology to determine the sociopolitical forces influencing lunar development policies

The rate of progress in any particular program is primarily dependent on the annual resources committed for the specific program. Soon after the turn of the century, the question of returning to the Moon will probably be raised again among political decision makers. At that time the positive and negative arguments will have to be weighed again. A simple method to analyse the relevant force-field was developed comprising the following steps: (1) Definition of positive and negative forces; (2) cross-impact analysis between the individual forces producing relative weights; (3) probability analysis of the current relevance of the individual forces; (4) estimating resulting negative and positive partial force-fields as functions for selected years between 1960 and 2030; and (5) determination of the strength of the resulting force influencing a decision. An example is presented.     

Proton Events and X-ray Flares in the Last Three Solar Cycles

A database joining the available information about proton enhancements near the Earth and their possible solar sources is organized on the basis of proton measurements of the GOES and IMP-8 satellites, the data of neutron monitors, and GOES X-ray measurements. One thousand one hundred and forty-four proton events with energy > 10 MeV have been selected in the period from 1975 to 2003. More than a half of these events can be reliably related to X-ray solar flares. A statistical analysis shows the probability of observing solar protons near the Earth and their maximum flux value to be strongly dependent on the importance of a flare and its heliolongitude. Proton events are recorded after all suitably located (western) flares with X-ray importance > X5. The heliolongitude of a flare predetermines the character of the time profile of proton events in many respects. The relationship of proton events with the other characteristics of flares is established. The flares associated with proton enhancements are characterized by longer duration, slower rise to the X-ray maximum, smaller temperature, and larger length of the X-ray loops.__________Translated from Kosmicheskie Issledovaniya, Vol. 43, No. 3, 2005, pp. 171–185.Original Russian Text Copyright © 2005 by Belov, Garcia, Kurt, Mavromichalaki.     

The USSR and satellite communications : Competition and cooperation

This article examines the USSR's satellite communications provision in the international arena. The author first outlines the Intercosmos programme, collaboration between the USSR and France and India, and maritime satellite communications. He then discusses in detail the INTERSPUTNIK system, and Soviet international coverage and competitiveness in television. In conclusion, the complex interaction and overlap between cooperation and competition in space is explained.     

Regional Centres for Space Science and Technology Education and ICG Information Centres affiliated to the United Nations

Based on resolutions of the United Nations General Assembly, Regional Centres for Space Science and Technology Education were established in India, Morocco, Nigeria, Brazil and Mexico. Simultaneously, education curricula were developed for the core disciplines of remote sensing, satellite communications, satellite meteorology, and space and atmospheric science. This paper provides a brief summary on the status of the operation of the regional centres with a view to use them as information centres of the International Committee on Global Navigation Satellite Systems (ICG), and draws attention to their educational activities.     

New estimates of ionization potentials of four DIB molecular carriers.

We present a study of the behaviour and ionization properties of four Diffuse Interstellar Bands (DIBs) at lambda lambda 5780, 5797, 6379 and 6613 angstroms. In the lambda lambda 5797, 6379 and 6613 angstrom DIBs, substructures have recently been detected, indicating large gaseous molecular carriers. Studying DIBs in regions with different physical properties in terms of UV flux and density enables us to monitor the behaviour of the carriers and hence to constrain their nature. As a follow-up of Sonnentrucker et al. (1997), we add new lines of sight and generalize the results for lines of sight with 2 or 3 clouds. This refines the Ionization Potential estimates which are between 10 and 13 eV, hence reminiscent of PAH or fullerene cations for those DIBs.