Coronal radio-sounding detection of a CME during the 1997 Galileo solar conjunction

Frequency fluctuations of the Galileo S-band radio signal were recorded nearly continuously during the spacecraft’s solar conjunction from December 1996 to February 1997. A strong propagating disturbance, most probably associated with a coronal mass ejection (CME), was detected on 7 February when the radio ray path proximate point was on the west solar limb at about 54 solar radii from the Sun. The CME passage through the line of sight is characterized by a significant increase in the fluctuation intensity of the recorded frequency and by an increase in the plasma speed from about 234 km s⁻¹ up to about 755 km s⁻¹. These velocity estimates are obtained from a correlation analysis of frequency fluctuations recorded simultaneously at two widely-separated ground stations. The density turbulence power spectrum is found to steepen behind the CME front. The Galileo radio-sounding data are compared with SOHO/LASCO observations of the CME in the corona and with WIND spacecraft data near the Earth’s orbit.     

Software replacement of test module adapters for depot instrumentation due to obsolescence

Depot-level automatic test equipment has been used over the years by various facets of both the government and commercial industry. Over time, the instrumentation used in the depot will need to be repaired or replaced and, oftentimes, the older instruments are no longer serviceable or manufactured. This paper discusses how to replace the obsolete instrument and its associated hardware. Test module adapter with a software module and driver that allows compatibility between the original test executive and the modern instrument without re-hosting existing test program sets. Systems & Electronics, Inc. has implemented this procedure for a digitizer and precision DC power supply on a depot that utilizes the IEEE-488 general purpose interface bus (GPIB) for communication between the control computer and instrumentation.     

Simplified Solution for a Class of Fading Memory Filters

A fading memory filter is a least squares estimator (LSE) thatapplies an exponentially decaying weight to past measurements.When compared with a standard Kalman filter, its key advantagesare asymptotic stability and reduced sensitivity to modeling errors.This paper derives a simple solution for a class of fading memoryfilters, resulting in a reduction in computational complexity. Steadystate filter solutions are obtained for second-and third-order filtersused in a global positioning system (GPS) receiver for high dynamicvehicles.     

Human Factors R&D Requirements for Future Aerospace Cockpit Systems

Cockpits are rapidly changing from dedicated instruments to multifunction displays, integrated controls, and computer controlled subsystems. Solid-state displays, voice recognition, and artificial intelligence are just a few of the emerging technologies that will help the pilot perform his mission in the future. Early investigations involving mission analysis, sensor data, software development, and evaluations will be required to insure total integration. These new technologies will require extensive human factors research in the areas of anthropometry, displays, controls, human/computer interface, automation, and workload assessment to support the integration process. This research will help provide weapons systems that have increased survivability and reduced pilot workload. This paper addresses some of the human factors research that will be needed to help develop future cockpit systems. It also reviews the basic evolution of the crew station and some of the emerging technologies that will drive human factors research in the 1990s. In the past, crew systems were designed to provide each aircraft function with a corresponding instrument display, such as airspeed indicator, altimeter, attitude direction indicator, vertical velocity indicator, etc. The bulk of the information had to be integrated by the pilot. Present systems are in a state of transition. We are rapidly moving from individual instruments to multifunction displays. The C-17, HH-60, F-15E, B-1B, F-111D, and F-16C/D aircraft use multifunction, cathode-ray tube displays, some of which are color. Another trend is the continued increase in the use of integrated controls.     

Identification Techniques for SARSAT Signals

A process for the identification of emergency locator transmitter (ELT) signals related to search and rescue satellite-aided tracking (SARSAT) is presented. The ELT identification process is particularly important in order to increase the probability of detection and eliminate sources of interference from the data set. A set of ELT signal parameters is introduced and methods for estimating these parameters are developed. A theoretical analysis and performance evaluation of these methods is provided.     

Connection between the discrete auroral structures drifting equatorward during the substorm expansion phase and the energetic particle injections at the geostationary orbit

The formation of an auroral bulge with a bright dynamical arc at its polar boundary is one of the main manifestations of the magnetospheric substorm expansion phase at the ionospheric level. At the same time, the region of discrete aurora broadens not only polewards but equatorwards as well. The discrete forms of auroras moving equatorwards form a dynamical equatorial boundary of the auroral bulge shifting together with them. The paper presents a spatial-time comparison of the drifting discrete auroras to the injection of energetic particles at the geostationary orbit. It is shown that bursts in the fluxes of energetic particles at the LANL geostationary satellites located in the same sector of MLT correspond to the majority of drifting discrete auroral structures observed by the all-sky camera. In the cases when the bursts in the fluxes are absent, the minimum latitude reached by the auroral structures at the equatorward drift is higher than the ionospheric projection of the geostationary orbit. A possible relation of the drifting discrete auroras to the plasma stream jets in the plasma sheet is discussed.     

Chemical protection against ionizing radiation.

Some of the problems related to chemical protection against ionizing radiation are discussed with emphasis on: definition, classification, degree of protection, mechanisms of action and toxicity. Results on the biological response modifyers (BRMs) and on the combination of nontoxic (i.e. low) doses of sulphydryl radioprotectors and BRMs are presented.     

Instrumentation for investigation of the depth-dose distribution by the Liulin-5 instrument of a human phantom on the Russian segment of ISS for estimation of the radiation risk during long term space flights.

Described is the Liulin-5 experiment and instrumentation, developed for investigation of the space radiation doses depth distribution in a human phantom on the Russian Segment of the International Space Station (ISS). Liulin-5 experiment is a part of the international project MATROSHKA-R on ISS. The experiment MATROSHKA-R is aimed to study the depth dose distribution at the sites of critical organs of the human body, using models of human body-anthropomorphic and spherical tissue-equivalent phantoms. The aim of Liulin-5 experiment is long term (4-5 years) investigation of the radiation environment dynamics inside the spherical tissue-equivalent phantom, mounted in different places of the Russian Segment of ISS. Energy deposition spectra, linear energy transfer spectra, flux and dose rates for protons and the biologically-relevant heavy ion components of the galactic cosmic radiation will be measured simultaneously with near real time resolution at different depths of the phantom by a telescope of silicon detectors. Data obtained together with data from other active and passive dosimeters will be used to estimate the radiation risk to the crewmembers, verify the models of radiation environment in low Earth orbit, validate body transport model and correlate organ level dose to skin dose. Presented are the test results of the prototype unit. The spherical phantom will be flown on the ISS in 2004 year and Liulin-5 experiment is planned for 2005 year.     

Performance limits of sensor-scheduling strategies in electronic support

The case is considered in which a frequency-agile receiver (FAR) for electronic support (ES) attempts to intercept radar emissions over a wide search bandwidth. It was recently shown [1,2] that a random strategy exists in which the expected intercept time can be made arbitrarily close to linear as a function of the scan period of the radar. Can a deterministic strategy be devised in which a similar linear relationship exists for the maximum intercept time? By applying the celebrated arithmetic results of van der Waerden [3] and Szemeredi [4], we show that no such strategy is possible.