Cross Sections and Reaction Rates for Comparative Planetary Aeronomy

In this chapter we describe the current knowledge of a selection of collision processes and chemical reactions of importance to planetary aeronomy. Emphasis is placed on critical evaluation of what we know and what we wish we knew about fundamental processes required for interpretation, explanation, and modeling of atmospheric observations.     

The Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) on RBSP

The Electric and Magnetic Field Instrument and Integrated Science (EMFISIS) investigation on the NASA Radiation Belt Storm Probes (now named the Van Allen Probes) mission provides key wave and very low frequency magnetic field measurements to understand radiation belt acceleration, loss, and transport. The key science objectives and the contribution that EMFISIS makes to providing measurements as well as theory and modeling are described. The key components of the instruments suite, both electronics and sensors, including key functional parameters, calibration, and performance, demonstrate that EMFISIS provides the needed measurements for the science of the RBSP mission. The EMFISIS operational modes and data products, along with online availability and data tools provide the radiation belt science community with one the most complete sets of data ever collected.     

Orbital debris - status and possibilities for control

This article is a shortened version of a position paper on orbital debris compiled by an Ad hoc Expert Group of the International Academy of Astronautics' Committee on Safety, Rescue and Quality. Its objectives were to elaborate on the need and urgency for action and to indicate ways for its implementation. The article reviews debris control options and methods ranging from those requiring no technology development to those which require new and thus far untried developments.     

A maintenance-free lead acid battery for inertial navigationsystems aircraft

Historically, aircraft inertial navigation system (INS) batteries have utilized vented nickel-cadmium batteries for emergency DC power. The United States Navy and Air Force developed separate systems during their respective INS developments. The Navy contracted with Litton industries to produce the LTN-72 and Air Force contracted with Delco to produce the Carousel IV INS for the large cargo and specialty aircraft applications, over the years, a total of eight different battery national stock numbers (NSNs) have entered the stock system along with 75 battery spare part NSNs. The standard hardware acquisition and reliability program is working with the Aircraft Battery Group at Naval Surface Warfare Center Crane Division, Naval Air Systems Command (AIR 536), Wright Laboratory, Battelle Memorial Institute, and Concorde Battery Corporation to produce a standard INS battery. This paper discusses the approach taken to determine whether the battery should be replaced and to select the replacement chemistry. The paper also discusses the battery requirements, aircraft that the battery is compatible with, and status of Navy flight evaluation. Projected savings in avoided maintenance in Navy and Air Force INS systems is projected to be $14.7 million per year with a manpower reduction of 153 maintenance personnel. The new INS battery is compatible with commercially sold INS systems which represents 66% of the systems sold     

Early cardiovascular adaptation to zero gravity simulated by head-down tilt

The early cardiovascular adaptation to zero gravity, simulated by head-down tilt at 5 degrees, was studied in a series of 10 normal young men. The validity of the model was confirmed by comparing the results with data from Apollo and Skylab flights. Tilt produced a significant central fluid shift with a transient increase in central venous pressure, later followed by an increase in left ventricular size without changes in cardiac output, arterial pressure, or contractile state. The hemodynamic changes were transient with a nearly complete return to the control state within 6 hr. The adaptation included a diuresis and a decrease in blood volume, associated with ADH, renin and aldosterone inhibition.     

Fault Tolerant Computer System for the A129 Helicopter

The A129 integrated multiplex system (IMS) is a highly reliable computer system designed to implement automatic flight control, navigation, system monitoring, and other flight-critical and mission related tasks. The reliability of the IMS has been achieved through the development of hardware-implemented and software implemented fault-tolerance techniques which exploit several unique architectural and hardware characteristics. This paper describes the fault-tolerance design philosophy, the IMS architecture, the fault detection and fault recovery techniques, and the hardware and software structures. Also presented is a Markov reliability analysis which was used to quantify the reliability of the system.     

Nuclear power supplies in orbit

There are four dozen potentially dangerous radioactive satellites orbiting the Earth today. Currently planned launches will vastly increase their number, resulting in over three metric tons of fuel and fission products in orbit by the year 2000. This article describes the nuclear power supply systems used by both the USA and the USSR, and the actual and potential hazards and accidents involved. The author suggests that a programme for retrieving the majority of nuclear supplies in space is both necessary and economically possible.