The GGS/POLAR magnetic fields investigation

The magnetometer on the POLAR Spacecraft is a high precision instrument designed to measure the magnetic fields at both high and low altitudes in the polar magnetosphere in 3 ranges of 700, 5700, and 47000 nT. This instrument will be used to investigate the behavior of fieldaligned current systems and the role they play in the acceleration of particles, and it will be used to study the dynamic fields in the polar cusp, magnetosphere, and magnetosheath. It will measure the coupling between the shocked magnetosheath plasma and the near polar cusp magnetosphere where much of the solar wind magnetosphere coupling is thought to take place. Moreover, it will provide measurements critical to the interpretation of data from other instruments. The instrument design has been influenced by the needs of the other investigations for immediately useable magnetic field data and high rate (100+vectors s^–1) data distributed on the spacecraft. Data to the ground includes measurements at 10 vectors per second over the entire orbit plus snapshots of 100 vectors per second data. The design provides a fully redundant instrument with enhanced measurement capabilities that can be used when available spacecraft power permits.     

Proton phase space densities (0.5eV<Ep<5MeV) at midlatitudes from Ulysses SWICS/HI-SCALE measurements

Proton phase space densities in the solar wind frame from suprathermal velocities 10 km s^–1 to 30,000 km s^–1 (0.5 eV–5 MeV) were derived from combined SWICS and HISCALE measurements when Ulysses was at 5 AU and –24° heliolatitude. The period (19–23 January 1993) encompasses a forward/reverse shock pair (20 January, 0500 UT and 22 January, 0300 UT). Strong evidence is found for shock acceleration of pickup protons from interstellar hydrogen at all energies measured.     

Solar wind charge states measured by ULYSSES/SWICS in the south polar hole

The Ulysses mission now has an extensive data base covering several passes of the south polar coronal hole as the spacecraft proceeds to higher latitudes. Using composition measurements from the SWICS experiment on the Ulysses spacecraft, we have obtained charge state distributions, and hence inferred coronal ionization temperatures, for several solar wind species. In particular, we present an overview of Oxygen ionization temperature measurements, based on the O⁷⁺/O⁶⁺ ratio, for the period January 1993 until April 1994 (23°S to 61°S heliographic latitude), and detailed Oxygen, Silicon and Iron charge state distributions of the south polar hole during a two month period of nearly continuous hole coverage, Dec 1993–Jan 1994 (45°S to 52°S heliographic latitude).     

Epilogue: Cosmic Rays in the Active Heliosphere

Space Science Reviews -     

Aircraft Stores Interface Manual (ASIM) adopts paperlessinformation technology

During recent years, defense budgets have been cut across all services while the cost of maintaining current standards has risen. The Aircraft Stores Interface Manual (ASIM) Program Office found that maintaining a staff for paper updates was no longer feasible and was tasked by the North Atlantic Treaty Organization (NATO) Air Armament Working Party (AAWP) to digitize the ASIM manuals. Converting this information from paper to electronic media presented several challenges which are discussed. Adopting Paperless Information Technology and replacing “Snail Mail” with the World Wide Web is presented     

Optimal time-varying load sharing for divisible loads

A load sharing problem involving the optimal load allocation of divisible loads in a distributed computing system consisting of N processors interconnected through a bus-oriented network is investigated. For a divisible lend, the workload is infinitely divisible so that each fraction of the workload can be distributed and independently computed on each processor. For the first time in divisible load theory, an analysis is provided in the case when the processor speed and the channel speed are time varying due to background jobs submitted to the distributed system with nonnegligible communication delays. A numerical method to calculate the average of the time-varying processor speed and the channel speed and an algorithm to find the optimal allocation of the workload to minimize the total processing finish time are proposed via a deterministic analysis. A stochastic analysis which makes use of Markovian queueing theory is introduced for the case when arrival and departure times of the background jobs are not known     

Ultra-wideband impulse radar-an overview of the principles

Over the past decade, extensive research work has been carried out to develop the ultra-wideband (UWB) technology for radar applications, and to resolve the practical challenges in implementing an efficient UWB radar system. In this paper, we present an overview of the basic principles of UWB impulse radar. The focus is on the principles of UWB signal generation, impulse radiation, waveform design, pulse compression, range-velocity resolution (ambiguity function), array beamforming, and radar-target signature     

THE CLUSTER DATA PROCESSING SYSTEM: A DISTRIBUTED SYSTEM IN SUPPORT OF A CHALLENGING SCIENTIFIC MISSION

The Cluster mission is aimed at the study of small-scale structures that are believed to be fundamental in determining the behaviour of key interactive processes of cosmic plasma. The mission will be controlled from the European Space Operations Centre (ESOC). ESOC is also in charge of the commanding of the scientific payloads on-board the four Cluster spacecraft after negotiation with the Cluster Principal Investigators (PIs) and of collecting and distributing the mission's scientific results to the Cluster community. This paper describes the process of translating the scientific requirements of the Cluster mission into a data-processing system supporting the mission via the definition of an appropriate operational scenario. In particular, the process of negotiation between the PIs and ESOC to command the spacecraft is mediated by the Joint Science Operations Centre (JSOC) and finalised by the Cluster Mission Planning System (CMPS) while the return of the data to the Cluster community is actuated by the Cluster Data Disposition System (CDDS). The Cluster Mission Control System (CMCS) provides the interface between these two systems and the spacecraft. These elements constitute the Cluster Data-Processing System (CDPS).