Showing papers in "Acta Astronautica in 1990"

TL;DR: The results indicate that eccentric rotation is a valuable method to test for bilateral otolith asymmetries and can be applied to preflight tests of astronaut candidates for susceptibility to spacesickness and for clinical evaluation of unilateral otolith impairments.

TL;DR: There appears to be a new organization of the cognitive image of the body scheme, the missing vestibular information being supplied by peripheral vision instead which could play a role in the astronaut's perception of his own movement.

TL;DR: The instability of liquid and gas interface can be induced by the pressure of longitudinal and lateral accelerations, vehicle vibration, and rotational fields of spacecraft in a microgravity environment as mentioned in this paper.

TL;DR: In this article, the authors reviewed complex interactions between flexibility, deployment, environmental forces and attitude dynamics during both steady state and transient phases of a spacecraft during both static and dynamic phases.

TL;DR: In this paper, the trajectory of an aero-assisted flight experiment (AFE) is analyzed in a 3D space, employing the full system of 6 ordinary differential equations (ODEs) describing the atmospheric pass.

TL;DR: In this paper, a detailed analysis of the critical population for the setting-in of a chain reaction is presented, and it is shown that this critical population is only about 2 to 3 times the current population and could be reached within 20 to 50 years, if spaceflight activities will be continued as in the past.

TL;DR: Only carefully-planned experiments in space preceded by thorough ground-based studies can provide the information needed to increase the amount of time humans can safely spend in space.

TL;DR: In this paper, the minimum altitude reachable by the probe is estimated based upon considerations of dynamic stability, tether temperature, resistance of the tether material, and propellant consumption required to maintain a constant orbital altitude.

TL;DR: In this article, the requirements for a photovoltaic powered lunar base are discussed, including requirements for power during the lunar day and during the night, solar cells, present and future availability, efficiency, specific power, and temperature sensitivity, storage options for the lunar night, arrays and system integration, and the potential for production of photoltaic arrays and storage capability from locally available materials.

TL;DR: The nominal Hipparcos mission is outlined, with the definition of its scientific goals and the description of the major design characteristics of the satellite and its payload.

TL;DR: In this article, the unsteady thermocapillary flow with deformable free surface in a two-dimensional, rectangular thin liquid bridge is investigated theoretically, where the temperature is fixed at one end and sinusoidally varied at the other end.

TL;DR: The impact on human society of radio contact with an extraterrestrial civilization vary widely between paranoid projections that contact with advanced extraterrestrials would quickly devastate the human spirit, and pronoid predictions that the extraterrestrial would be so advanced that they would swiftly and benevolently lead us into a golden age as mentioned in this paper.

TL;DR: It was concluded that negative water balance evidently resulted not from shortage of water in the diet but from the inability of the body to retain optimum amounts of fluid under HK and a set of intensive PEs.

TL;DR: The Cassini mission is a joint ESA NASA mission for the exploration of the Saturnian System as discussed by the authors, which consists of two components: an Orbiter designed to tour Saturn for 4 years and an atmospheric Probe to Titan, Saturn's largest moon.

TL;DR: In this article, the authors demonstrate validity of the mathematical model aimed at studying offset control of an orbiting platform supported tethered satellite system using a ground-based experimental facility, and demonstrate the effectiveness of the offset control strategy during both the stationkeeping and retrieval phases.

TL;DR: In this paper, the exact form of the solar radiation pressure on a heliocentric orbiting solar sail is obtained for a finite angular sized solar disk by the use of specific intensity calculation.

TL;DR: In this article, the response of a viscous liquid column to counter-directional one-sided and phase-different pitching excitation of the walls between which the column is placed has been presented in zero-gravity environment.

TL;DR: In this paper, the exact dimensionless equations of motion and the necessary conditions for the computation of the optimal trajectories of a hypervelocity vehicle flying through a non-rotating spherical planetary atmosphere are presented.

TL;DR: The experiments vaidate the concept of the hybrid navigation system and confirm its capability to realize space autonomy and its feasibility for space application in the point of existing hardware technology.

TL;DR: In this paper, the main elements and sub-systems of a Microgravity Isolation Mount (MGIM) based on this non-contact strategy and designed to be accommodated inside a Columbus single rack are described.

TL;DR: In this article, the dynamics of a space manipulator designed to be set on a servicing satellite (S 0 ) and to grasp another satellite (P 0 ) are investigated, where a continuum approach is used to describe distributed flexibility in the manipulator.

TL;DR: In this paper, the authors identify the status of technology on the following: 1) Aluminium and titanium alloys and their composites, 2) Superalloys and superalloys, 3) Carbon, glass-ceramic and ceramic matrix composites.

TL;DR: In this article, a number of system aspects, based on current technology parameter values, have been evaluated for kilometric optical arrays and it has been shown that such structures are not only of low mass (0.8 -1.8 kg/m baseline) and efficient packaging but also provide a thermally stable backbone, with sufficient stiffness to make attitude control easily manageable and offering the promise of good separation between the equipment and the sensors at critical high frequencies, where backbone stability is mandatory to make astronomical observations possible.

TL;DR: In this article, the dynamics of fully developed, fully developed dispersed liquid-vapor flow in a straight duct at 0-g is simulated by flowing water containing n-butyl benzoate droplets.

TL;DR: In this paper, a Lagrangian formulation for studying the dynamics and control of the proposed Space Station based Mobile Servicing System (MSS) for a particular case of inplane libration and maneuvers is presented.

TL;DR: The success of Consort 1 demonstrated the ability of industry, working with university centers and government agencies, to rapidly prepare and launch payloads.

TL;DR: In this paper, the authors studied the instantaneous energy of a spacecraft by means of its Karhunen-Loeve eigenfunction expansion and proved that the eigenfunctions are Bessel functions of the first kind and order zero.

TL;DR: In this article, a committee of representatives of governmental and non-governmental organizations is proposed for a wise and cautious analysis of the matter, and the creation of a committee is discussed.

TL;DR: In this paper, the authors present the pump design and analyses and the results from the test campaigns of three different pump configurations, carried out with water as test liquid, and also give the head rise, efficiency and suction performance together with other characteristics.

TL;DR: In this paper, the authors discuss the possible need for partial restriction of data about the location and channel of a suspected signal in the case of SETI signals, and propose three steps to alleviate the particularly difficult factors (numbers 4, 5, 6): an international treaty for immediate sharing of possible signals with SETI scientists in several other countries; implementation and frequent use of an actual network of scientists for such sharing; and further study of the possible needing for partial restricting of data.