Application of Endfire Arrays at Contemporary Glide-Slope Problem Sites

The application of the endfire-type, compatible instrument landing system (ILS) glide slope is discussed in the context of providing increased capability to install facilities without requirements for extensive terrain modification. Costs of preparing a site for glide-slope operation can be reduced many times by eliminating the requirement for the usual image-forming ground plane. An example is given where the first endfire glide slope has been installed at an airdrome on a mesa giving a high quality path in space in spite of the limited real estate. Recent flight data from this glide slope are presented.     

罗-罗在A3XX发动机竞争中首战告捷

在Ａ３ＸＸ的发动机竞争中，英国罗－罗公司的遄达９００选用于新加坡航空公司订购的Ａ３ＸＸ     

High temperature alters the growth reaction of Pottia protonemata.

Under gravistimulation, dark-grown protonemata of Pottia intermedia revealed negative gravitropism with a growth rate of approximately 28 μm·h⁻¹ at room temperature (20 °C). In 7 days, the protonema formed a bundle of vertically oriented filaments. At an elevated temperature (30 °C), bundles of vertically growing filaments were also formed. However, both filament growth rate and amplitude of the gravicurvature were reduced. Red light (RL) irradiation induced a positive phototropism of most apical protonemal cells at 20 °C. In a following period of darkness, approximately two-thirds of such cells began to grow upward again, recovering their negative gravitropism. RL irradiation at the elevated temperature caused a partial increase in the number of protonemal cells with negative phototropism, but the protonemata did not exhibit negative gravitropism after transfer to darkness. The negative gravitropic reaction was renewed only when protonemata were placed at 20 °C. A dramatic decrease in starch amount in protonemal apical cells, which are sensitive to both gravity and light, occurred at the higher temperature. Such a decrease may be one of the reasons for the inhibition of the protonemal gravireaction at the higher temperature. The observation has a bearing on the starch-statolith theory.     

Radiation measurements on the flight of IML-2.

The second flight of the International Microgravity Laboratory (IML-2) on Space Shuttle flight STS-65 provided a unique opportunity for the intercomparison of a wide variety of radiation measurement techniques. Although this was not a coordinated or planned campaign, by sheer chance, a number of space radiation experiments from several countries were flown on this mission. There were active radiation measuring instruments from Japan and US, and passive detectors from US, Russia, Japan, and Germany. These detectors were distributed throughout the Space Shuttle volume: payload bay, middeck, flight deck, and Spacelab. STS-65 was launched on July 8, 1994, in a 28.45 degrees x 306 km orbit for a duration of 14 d 17 hr and 55 min. The crew doses varied from 0.935 mGy to 1.235 mGy. A factor of two variation was observed between various passive detectors mounted inside the habitable Shuttle volume. There is reasonable agreement between the galactic cosmic ray dose, dose equivalent and LET spectra measured by the tissue equivalent proportional counter flown in the payload bay with model calculations. There are significant differences in the measurements of LET spectra measured by different groups. The neutron spectrum in the 1-20 MeV region was measured. Using fluence-dose conversion factors, the neutron dose and dose equivalent rates were 11 +/- 2.7 microGy/day and 95 +/- 23.5 microSv/day respectively. The average east-west asymmetry of trapped proton (>3OMeV) and (>60 MeV) dose rate was 3.3 and 1.9 respectively.     

Mean winds of the mesosphere and lower thermosphere (60–110 km): A global distribution from radar systems (MF,Meteor, VHF)

During the last decade a large number of radars (～12) have been developed, which have produced substantial quantities of tidally-corrected mean winds data. The distribution of the radars is not global, but many areas are well covered: the Americas with Poker Flat (65°N), Saskatoon (52°N), Durham (43°N), Atlanta (34°N), Puerto Rico (18°N); Europe with Kiruna (68°), Garchy (47°N) and Monpazier (44°N); and Oceania with Christchurch (44°S), Adelaide (35°S), Townsville (20°S), and Kyoto (35°N). Zonal and meridional wind height-time cross-sections from $\text{60}\text{80}$ km (MF/Meteor Radar) to ～110 km have been prepared for the last 5–6 years. They are compared with cross-sections from CIRA-72 for zonal winds, and Groves (1969) for meridional winds.It is shown that while CIRA-72 is still a useful model for many purposes, significant differences exist between it and the new radar data. The latter demonstrate important seasonal, latitudinal, longitudinal and hemispheric variations. The new meridional cross-sections are of great value. The common features with Groves (1969) are the equatorward cells in summer near 85 km; however their strength (～10 ms^?1) and size are less. Systematic and somewhat different variations emerge at higher (?52°N) and middle (35–44°) latitudes.     

A proposed international tropical reference atmosphere up to 80 km

Motivated by the need in many aerospace applications for a meaningful reference atmosphere characteristic of the whole of the tropics in both the northern and southern hemispheres of the globe, a proposal is made here for such an atmosphere upto an altitude of 80 km. The proposal is based on balloonsonde, rocketsonde and grenade and falling sphere data, respectively, in the range of about 0–20, 20–50 and 50–80 km height. The final proposal consists of six linear segments in the temperature distribution, with temperature values in degrees Centigrade of 27, ?9, ?74, ?5, ?5, ?74 and ?74 at altitudes of 0, 9, 16, 46, 52, 75 and 80 km respectively. The sea level pressure is taken as 1010 mb, and abridged tables of quantities of interest in meteorological and aerospace applications are provided.     

The contributions of the incoherent scatter radar technique to the development of thermospheric models

The contributions of the incoherent scatter radar technique to the development of thermospheric models is traced from the development of the radar technique in 1958. Emphasis is given to the qualitative information regarding thermospheric processes and behavior provided by the radar studies and the role that these results have played in the structural development of thermospheric models. The complementary nature of radar and satellite data in the development of recent models is stressed. In addition, a summary of pertinent radar developments over the past two years is presented. Primary among these are measurements made by high-latitude radars, multi-radar coordinated observations, the establishment of an incoherent scatter radar data base, and publication of a number of studies concerning high-latitude measurements, solar-cyle maximum results, long-term data sets, and lower thermosphere tides.     

Synthetic Environments for Simulated Missions

Synthetic environments offer Space Flight projects an opportunity to perform rapid, comprehensive, and rigorous modeling of the critical elements of a mission in order to compute quantitative measures of design performance, associated risk, and actual mission utility value. Significantly, these studies can be performed early in the mission cycle. These synthetic terrains are generated on parallel, high-performance computers and served to remote simulations at near-interactive speeds. The terrain creation uses a realistic sequence of physical phenomena such as cratering and dusting with parametric control of features such as surface roughness and rock density. Terrain resolution may be arbitrary but typically ranges from 0.01 to 10 meters. The terrain server has been used for two rover simulations, one using the actual Sojourner autonomy flight code, and the other a more general algorithm. Monte Carlo studies of rover designs interacting with synthetic environments were executed in parallel to quickly compute performance statistics and risk estimates.     

Study of the radiation environment on MIR space station with SILEYE-2 experiment.

In this work we present preliminary results of nuclear composition measurements on board space station MIR obtained with SILEYE-2 particle telescope. SILEYE-2 was placed on MIR in 1997 and has been working since then. It consists of an array of 6 active silicon strip detectors which allow nuclear and energetic identification of cosmic rays in the energy range between approximately 30 and 200 MeV/n. The device is attached to an helmet and connected to an eye mask which shields the cosmonaut eyes from light and allow studies of the Light Flashes (LF) phenomenon. In addition to the study of the causes of LF, the device is used to perform real time long term radiation environment monitoring inside the MIR, performing measurements in solar quiet and active days.     

A low cost steerable radio-telescope

We present the technical characteristics of a low-cost radio telescope for solar/non solar observations at decimetric (1200–1700 MHz) and centimetric (2700 and 5000 MHz) wavelengths known as Brazilian Decimetric Array (BDA). The technical specifications of the antenna, tracking system, log-periodic feed, preamplifier and the frequency-synthesised receiver with a Single Side Band (SSB) video output of 2.5 MHz are given.