Ferri project: technologies to support advanced transportationsystems

The authors present the plan under discussion in Italy between the government entities and Aeritalia, the leading Italian aerospace company, for the technology development needed to support advanced transportation systems. The plan centers around the following areas: thermal protection and control; advanced structures and materials; guidance, navigation, and control; and tests and computation methods. Experimental activities needed to support the development of such systems and the difficulties involved are examined     

Some problems of very high-energy gamma-ray astronomy

The latest achievements in very high-energy (VHE) gamma-ray astronomy are discussed. Types of candidate objects for the sources of very high-energy gamma-quanta are considered, and pulsars, as the most probable ones, are anticipated. The objectives of VHE gamma-ray astronomy are presented, outlining the pressing need for complex observations of individual objects.     

Covert Penetration Systems

This paper discusses past, present, and future strategic aircraft requirements for ingress and egress, then focuses on the technologies of the CO2 Laser Radar and the Automatic Target Recognizer. Present systems currently consist of a mix of various sensors which are not correlated until each is presented to the operator. Additionally, active sensors are highly detectable by threat warning systems, while passive sensors do not provide critical range information. CO2 Laser and ATR technologies will significantly contribute to the resolution of these issues.     

Microwave Landing System

The National Microwave Landing Systems (MLS) program is a joint DOT/DOD/NASA effort to implement a common civil/military precision landing system to replace the current Instrument Landing System (ILS). The MLS will be capable of providing precision landing guidance down to Category III minimum while allowing for complex approach paths in both the horizontal and vertical planes. The system is based on the Time Reference Scanning Beam (TRSB) technique which was selected by the International Civil Aviation Organization (ICAO) in April 1978 as the new international landing system standard. MLS is less susceptible to interference from the surrounding area and provides a greater signal coverage area than ILS.     

Strapdown inertial measurement units for motion compensation forsynthetic aperture radars

It is shown that synthetic-aperture radar (SAR) motion can be compensated by using an antenna-mounted strapdown inertial measurement unit (IMU) as the motion sensing system, but sensor and system errors affect SAR image quality. A strapdown IMU consists of three accelerator channels and three gyro channels. Strapdown IMU errors include gyro-scale and accelerometer-scale factor and bias errors, velocity error, platform tilt, and errors induced by limited inertial sensor bandwidth. The effects of these errors on the SAR image quality are presented in terms of the SAR impulse response. IMU errors that cause low-frequency phase errors (less than one cycle per array time) are categorized in terms of quadratic and cubic phase errors. IMU errors that cause high-frequency phase errors (greater than one cycle per array time) are categorized in terms of the integrated sidelobe ratio and peak sidelobe ratio. A motion compensation system conceptualization is described wherein a strapdown IMU is attached to an antenna and transfer-aligns to the aircraft's master navigator     

The cosmic ray solar diurnal anisotropy

This paper reviews the present state of knowledge concerning the diurnal and semidiurnal variations in the galactic cosmic ray intensity. The analytical procedures that are required for extracting from the original data the desired information concerning the characteristics of the anisotropies outside the magnetosphere are described. These include corrections for atmospheric fluctuations, the determination of the amplitudes and phases of the daily variations, and their interpretation in terms of the free space anisotropies that give rise to them. The experimental results concerning the 24-h wave, including its long-term variations with periods of one and two solar cycles, and the characteristics of the total diurnal anisotropy are then discussed. The semidiurnal anisotropy is considered next. Transient anisotropies which manifest themselves as day-to-day variations, recurrence tendencies, cosmic ray storms, and diurnal variation trains, and which can introduce appreciable changes in the spectral parameters, are also of interest. The evolution of theoretical models developed to account for the diurnal and semidiurnal anisotropies, and fluctuations thereof, are then discussed in the light of the experimental results. Finally, the general features that are now well established, and the nature of the remaining problems, are summarized.     

Spectroscopic study of plasma parameters for solar active regions and flares

Results are given of the study of active regions and flares by a high resolution Mg XI ion spectra obtained aboard rockets and a satellite. It is shown that there is a noticable similarity in the physical conditions in the plasma of active regions and flares. Plasma of both sources consists okf a thermal component with the temperature T ～ 2.?3.10⁶K for active regions and T ～ 1.5?2.5.10⁷K for flares and in both cases of a relatively small number (～ 1–5%) of suprathermal electrons with an energy E ～ 3–6 kT.     

Microorganisms and biomolecules in space environment experiment ES 029 on Spacelab-1.

Bacterial spores are proper test organisms for studying problems of space biology and exobiology. During the Spacelab 1 mission, studies on the limiting factors for survival of Bacillus subtilis spores in free space have been performed. An exposure tray on the pallet of Spacelab 1 accomodated 316 samples of dry spores for treatment with space vacuum and/or the following selected wavelengths of solar UV: > 170 nm, 220 nm, 240nm, 260nm and 280 nm. After recovery, inactivation, mutation induction, reparability, and photochemical damages in DNA and protein have been studied. The results contribute to the understanding of the mechanisms of increased UV sensitivity of bacterial spores in vacuo and to a better assessment of the chance of survival of resistant forms in space and of interplanetary transfer of life.     

Very high energy gamma-ray sources

A brief review of very high energy gamma-ray astronomy achievements is presented. The results of observations of the Crab nebula, the Cygnus X-3, Vela pulsar, radiogalaxy Centaurus A and 2CG 195+4 show that all these objects are the sources of very high energy gamma-quanta. The most powerfull source is Cygnus X-3. Its gamma-ray luminosity is no less than 3·10³⁷ erg.s⁻¹. The upper limit of quanta energy is no less than 10¹⁶eV. All sources are variable in different time scales, from milliseconds up to years. The nature of all these sources is not known yet, but known ones are pulsars.