Computation of Optimal Earth-Mars and Earth-Venus Trajectories

Accurate solutions of minimal time Earth-Mars and Earth-Venus heliocentric trajectories are calculated with a shooting-Newton method. The flight times are less and the steering histories are diferent than those presented in [1], thus contradicting the optimality claims in [1].     

Non-intrusive methods for temperature measurements in liquid zones in microgravity environments

Material Science and Life Science experiments in microgravity both have urgent needs of evaluating the temperature distribution within and on the surface of liquid zones. Non intrusive methods are available which measure the IR radiations emitted by the surface. The thermograph systems have a number of advantages since they supply a thermal picture of the surface with sufficient time, space and temperature accuracy. A computerized system has been designed for data acquisition and elaboration and used for ground experiments; the system can also be used for space experiments with some modifications. Non intrusive measurements of bulk temperature in two dimensional liquid flow fields can be made by means of optical methods which detect variations of the index of refraction. A method is proposed which is able to take with the same optical apparatus shadowgraph. Schlieren and differential interferometers pictures. A computerized system is proposed for data acquisition and elaboration.     

The Voyager mission Photopolarimeter Experiment

The Voyager Photopolarimeter Experiment is designed to determine the physical properties of particulate matter in the atmospheres of Jupiter, Saturn, and the Rings of Saturn by measuring the intensity and linear polarization of scattered sunlight at eight wavelengths in the 2350–7500 Å region of the spectrum. The experiment will also provide information on the texture and probable composition of the surfaces of the satellites of Jupiter and Saturn and the properties of the sodium cloud around Io. During the planetary encounters a search for optical evidence of electrical discharges (lightning) and auroral activity will also be conducted.     

Device for mass measurement under zero-gravity conditions.

The problem considered in this paper is the investigation of the properties of a mass-meter, i.e. the device for determining the mass of cosmonaut's body under zero-gravity conditions. The estimates of accuracy of mass measurement by this device are given, and the results of measuring the masses of cosmonauts' bodies on the Salyut 5 and 6 orbital stations are presented.     

Multiple wavelength observations of flaring active regions

We present observations of flaring active regions with the Very Large Array (V.L.A. at 6 cm and 20 cm wavelengths) and the Westerbork Synthesis Radio Telescope (W.S.R.T. at 6 cm wavelength). These are compared with photospheric magnetograms (Meudon) and with Hα and offband Hα photographs (Big Bear and Ottawa River Solar Observatories). The 6 cm radiation of these active regions marks the legs of dipolar loops which have their footpoints in lower-lying sunspots. The intense, million degree radiation at 6 cm lies above sunspot umbrae in coronal regions where the longitudinal magnetic field strength H_? = 600 Gauss and the height above the sunspot umbrae h = 3.5±0.5 × 10⁹ cm. Circularly polarized horseshoe structures at 6 cm ring the sunspot umbrae. The high degree of circular polarization (?_c = 95%) of the horseshoes is attributed to gyroresonant emission above sunspot^? penumbrae. The 20 cm radiation of these active regions exhibits looplike coronal structures which extend across regions of opposite magnetic polarity in the underlying photosphere. The 20 cm loops are the radio wavelength counterparts of the X-ray coronal loops. We infer semilengths L = 5 × 10⁹ cm, maximum electron temperatures T_e(max) = 3 × 10⁶ K, emission measures ∫N_e²d$\text{l}$ = 10²⁸ cm^?5, and electron densities N_e = 10⁹ cm^?3 (or pressures p = 1 dyn cm^?2) for the 20 cm bremsstrahlung. A total of eight solar bursts were observed at 6 cm or 20 cm wavelength with second-of-arc angular resolution. The regions of burst energy were all resolved with angular sizes between 5″ and 30″, brightness temperatures between 2 × 10⁷ K and 2 × 10⁸ K, and degrees of circular polarization between 10% and 90%. The impulsive phase of the radio bursts are located near the magnetic neutral lines of the active regions, and between the flaring Hα kernels which mark the footpoints of magnetic loops. In one case there was preburst heating in the coronal loop in which a burst occurred. Snapshot maps at 10 s intervals reveal interesting burst evolution including rapid changes of circular polarization and an impulsive burst which was physically separated from both the preburst radio emission and the gradual decay phase of the burst.     

Approximate Ellipsoidal-Earth Equations for Mapping and Fix-Taking Calculations

Approximate equations are developed for converting geodetic coordinates to a local north-east-down (NED) Cartesian coordinate system, and it is shown that good accuracy can be obtained if the ellipsoidal shape of the Earth is taken into account.     

Siple VLF transmissions and their magnetospheric effects observed at Halley,Antarctica

Halley (75.5°S, 26.7°W, L = 4.3) is well placed for reception of subionospheric signals from the Siple transmitter. Occasionally a two-hop magnetospheric response to such signals can be observed. The data presented here are relevant to the problems of the radiation and propagation of VLF waves in the polar earth/ionosphere waveguide, duct stimulation and ducted wave amplification and the growth of triggered emissions. An upper sideband emission 20–40 Hz higher in frequency than the transmitted pulse was often received at a similar strength to, and simultaneously with the two-hop whistler mode echo.     

Heavy ion action on yeast cells: inhibition of ribosomal-RNA synthesis, loss of colony forming ability and induction of mutants.

The action of heavy ions (Ar to U) accelerated to specific energies up to about 10 MeV/u (u=atomic mass unit) on different functions of yeast cells was studied. Ribosomal-RNA synthesis is inhibited according to a single-hit mechanism. Inactivation cross-sections were linearly related to the ratio of the squares of the effective charge Z* and the velocity of the ions. It is concluded from the analysis that the range of the most energetic delta-electrons is larger than previously assumed. There is no such dependence for survival and induction of mutants. In both cases cross-sections increase with the ion's specific-energy indicating an important contribution of long-range delta-electrons. The analysis shows that diploid yeast is not killed by a single-hit mechanism even by very heavy ions if the track width is too small. The relative importance of the penumbral region is even more pronounced with the more sensitive strains.     

Preflare heating of filaments

Disappearances of preflare filaments have been observed on June 22, 1980 (S07,W13) (flare at 13.04 U.T.) and September 3, 1980 (flare at 7.52 U.T.). The analysis of MSDP data (MEUDON) leads to the followings conclusions : - Disappearances begin a few minutes before the Hα impulsive phase. - The filaments can be seen again after the flares. - Upwards motions occur in several points, without disturbing significantly preëxisting downflows.Velocity maps suggest shears or velocity loops.The filament disappearance seems to be due to a heating mechanism beginning before the flare maximum.