Analysis of conventional and asymmetric aircraft configurations using CEASIOM

One of the main drivers behind the SimSAC project and the CEASIOM software is to bring stability analysis and control system design earlier into the aircraft conceptual design process. Within this paper two very different aircraft are considered, a conventional T-tail based on the existing EA500 Very Light Jet and the second, a novel Z-wing configuration known as the GAV or general aviation vehicle. The first aircraft serves as a baseline comparison for the second, and the cruise case is considered as a benchmark for identifying potential drag reductions and aircraft stability characteristics. CEASIOM, the Computerised Environment for Aircraft Synthesis and Integrated Optimisation Methods, is used to generate aerodynamic data sets for both aircraft, create trim conditions and the associated linear models for classical stability analysis. The open-loop Z-wing configuration is shown to display both highly unstable and coupled modes before a multivariable Stability Augmentation System (SAS) is applied both to decouple and stabilise the aircraft. Within this paper, these two aircraft provide a test case with which to demonstrate the capabilities of the CEASIOM environment and the tools which have been developed during the SimSAC project. This new software suite is shown to allow conceptual development of unconventional novel configurations from mass properties through adaptive-fidelity aerodynamics to linear analysis and control system design.     

Black Hole Studies: Overview and Outlook

In this article, I will attempt to give an overview of the motivations for studying black holes and of the current major problems in the field. I will also give some perspectives on what can be done in the future, focusing on instrumentation which has already been approved. This chapter will necessarily be more speculative than the other chapters in this volume.     

Signatures of the Sudden Stratospheric Warming events of January–February 2008 in Seoul,S. Korea

The period January–February 2008 was characterized by four Sudden Stratospheric Warmings (SSWs) in the Northern Hemisphere, of which the last warming, at the end of February 2008, was a major warming. A significant decrease in mesospheric water vapour (H₂O) of more than 2 ppmv (∼40%) was observed by the ground-based microwave (GBMW) radiometer in Seoul, S. Korea [37.3°N, 126.3°E] during the major SSW. A comparison with ground-based mesospheric H₂O observations from the mid-latitude station in Bern [46.9°N, 7°E] revealed an anticorrelation in the mesospheric H₂O data during the major SSW. In addition, prior to the major warming, strong periodic fluctuations were recorded in the Aura MLS vertical temperature distribution between 15 and 0.05 hPa at Seoul. The mesospheric temperature oscillation was found to have a period of ∼10–14 days with a persistency of 3–4 cycles.     

Michelson Interferometer for Global High-Resolution Thermospheric Imaging (MIGHTI): Instrument Design and Calibration

The Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI) instrument was built for launch and operation on the NASA Ionospheric Connection Explorer (ICON) mission. The instrument was designed to measure thermospheric horizontal wind velocity profiles and thermospheric temperature in altitude regions between 90 km and 300 km, during day and night. For the wind measurements it uses two perpendicular fields of view pointed at the Earth’s limb, observing the Doppler shift of the atomic oxygen red and green lines at 630.0 nm and 557.7 nm wavelength. The wavelength shift is measured using field-widened, temperature compensated Doppler Asymmetric Spatial Heterodyne (DASH) spectrometers, employing low order échelle gratings operating at two different orders for the different atmospheric lines. The temperature measurement is accomplished by a multichannel photometric measurement of the spectral shape of the molecular oxygen A-band around 762 nm wavelength. For each field of view, the signals of the two oxygen lines and the A-band are detected on different regions of a single, cooled, frame transfer charge coupled device (CCD) detector. On-board calibration sources are used to periodically quantify thermal drifts, simultaneously with observing the atmosphere. The MIGHTI requirements, the resulting instrument design and the calibration are described.     

Comparison of the transport codes HZETRN,HETC and FLUKA for galactic cosmic rays

The HZETRN deterministic radiation code is one of several tools developed to analyze the effects of harmful galactic cosmic rays (GCR) and solar particle events on mission planning and shielding for astronauts and instrumentation. This paper is a comparison study involving the two Monte Carlo transport codes, HETC–HEDS and FLUKA and the deterministic transport code, HZETRN. Each code is used to transport an ion from the 1977 solar minimum GCR spectrum impinging upon a 20 g/cm² aluminum slab followed by a 30 g/cm² water slab. This research is part of a systematic effort of verification and validation to quantify the accuracy of HZETRN and determine areas where it can be improved. Comparisons of dose and dose equivalent values at various depths in the water slab are presented in this report. This is followed by a comparison of the proton and forward, backward and total neutron flux at various depths in the water slab. Comparisons of the secondary light ion ²H, ³H, ³He and ⁴He fluxes are also examined.     

Parabolic maneuvers of the Swiss Air Force fighter jet F-5E as a research platform for cell culture experiments in microgravity

Long-term sensitivity of human cells to reduced gravity has been supposed since the first Apollo missions and was demonstrated during several space missions in the past. However, little information is available on primary and rapid gravi-responsive elements in mammalian cells. In search of rapid-responsive molecular alterations in mammalian cells, short-term microgravity provided by parabolic flight maneuvers is an ideal way to elucidate such initial and primary effects. Modern biomedical research at the cellular and molecular level requires frequent repetition of experiments that are usually performed in sequences of experiments and analyses. Therefore, a research platform on Earth providing frequent, easy and repeated access to real microgravity for cell culture experiments is strongly desired. For this reason, we developed a research platform onboard the military fighter jet aircraft Northrop F-5E “Tiger II”. The experimental system consists of a programmable and automatically operated system composed of six individual experiment modules, placed in the front compartment, which work completely independent of the aircraft systems. Signal transduction pathways in cultured human cells can be investigated after the addition of an activator solution at the onset of microgravity and a fixative or lysis buffer after termination of microgravity. Before the beginning of a regular military training flight, a parabolic maneuver was executed. After a 1 g control phase, the parabolic maneuver starts at 13,000 ft and at Mach 0.99 airspeed, where a 22 s climb with an acceleration of 2.5g is initiated, following a free-fall ballistic Keplerian trajectory lasting 45 s with an apogee of 27,000 ft at Mach 0.4 airspeed. Temperature, pressure and acceleration are monitored constantly during the entire flight. Cells and activator solutions are kept at 37 °C during the entire experiment until the fixative has been added. The parabolic flight profile provides up to 45 s of microgravity at a quality of 0.05g in all axes. Access time is 30 min before take-off; retrieval time is 30 min after landing. We conclude that using military fighter jets for microgravity research is a valuable tool for frequent and repeated cell culture experiments and therefore for state-of-the art method of biomedical research.     

Analysis of carbonaceous biomarkers with the Mars Organic Analyzer microchip capillary electrophoresis system: carboxylic acids

The oxidizing surface chemistry on Mars argues that any comprehensive search for organic compounds indicative of life requires methods to analyze higher oxidation states of carbon with very low limits of detection. To address this goal, microchip capillary electrophoresis (μCE) methods were developed for analysis of carboxylic acids with the Mars Organic Analyzer (MOA). Fluorescent derivatization was achieved by activation with the water soluble 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) followed by reaction with Cascade Blue hydrazide in 30 mM borate, pH 3. A standard containing 12 carboxylic acids found in terrestrial life was successfully labeled and separated in 30 mM borate at pH 9.5, 20 °C by using the MOA CE system. Limits of detection were 5-10 nM for aliphatic monoacids, 20 nM for malic acid (diacid), and 230 nM for citric acid (triacid). Polyacid benzene derivatives containing 2, 3, 4, and 6 carboxyl groups were also analyzed. In particular, mellitic acid was successfully labeled and analyzed with a limit of detection of 300 nM (5 ppb). Analyses of carboxylic acids sampled from a lava tube cave and a hydrothermal area demonstrated the versatility and robustness of our method. This work establishes that the MOA can be used for sensitive analyses of a wide range of carboxylic acids in the search for extraterrestrial organic molecules.     

On Truncation Error Bounds for Sampling Representations of Band-Limited Signals

All sampling representations of band-limited signals involve infinite sums. The truncation error associated with a given representation is defined as the difference between the signal and an approximating sum utilizing a finite number of terms. In this paper truncation error is expressed as a contour integral for Lagrange interpolation, general Hermite interpolation, the Shannon series (cardinal series), the Fogel derivative series, and multidimensional sampling expansions. Truncation error bounds are obtained under various constraints on the signal magnitude, spectral smoothness, and energy content.     

High resolution solar ultraviolet measurements

The increase of our understanding of the processes acting in the solar corona and maintaining it is strongly dependent on the quality of the data that are obtained to check theories. The fine structure of the solar atmosphere seen from the photosphere and extending to the hottest parts of the corona requires data with high resolution in all parameter space (angular, spectral and temporal). To constrain the hypotheses that are proposed to describe the solar corona, it is necessary to establish an accurate energy budget taking into account the processes which are acting from the chromosphere to the corona. Some requirements can be established and compared with the data collected so far (or about to be collected) with the present SUMER (Solar Utraviolet Measurements of Emitted Radiations) instrumentation.     

Comets, Asteroids and Zodiacal Light as Seen by Iso

ISO performed a large variety of observing programmes on comets, asteroids and zodiacal light – covering about 1% of the archived observations – with a surprisingly rewarding scientific return. Outstanding results were related to the exceptionally bright comet Hale–Bopp and to ISO's capability to study in detail the water spectrum in a direct way. But many other results were broadly recognised: Discovery of new molecules in comets, the studies of crystalline silicates, the work on asteroid surface mineralogy, results from thermophysical studies of asteroids, a new determination of the asteroid number density in the main-belt and last but not least, the investigations on the spatial and spectral features of the zodiacal light.