Search Results

This paper describes the initial results of a simulation experiment in which the human factors implications of three Mixed Equipage, Integrated Air-Ground, Free Flight Air Traffic Management (ATM) scenarios were investigated. The experiment primarily addressed how to accommodate a fleet of mixed equipped aircraft, with and without Airborne Separation Assurance System (ASAS), in a transitional free flight era in which both air and ground players have defined responsibilities. All three transitional ATM operational concepts evaluated, were designed with the idea that equipping aircraft should be immediately beneficial to the airlines.

Various aspects of different sensors and components, (being) developed or fine-tuned for aerospace thermal control and propellant systems, are discussed, i.e.: rotatable radial heat pipe joints, vapour quality sensors, controllable valves, condensers, flow metering assemblies and propellant gauges.

Against the manufacturing requirement for both lower lead time and reduced machining time for titanium components, a new concept was conceived assembling sheet material and other stock into semi finished parts by (explosive) impact welding. It is believed that this concept (which we named SLAM) could be especially beneficial for titanium alloy and nickel alloy. The present investigation centered on the feasibility of this technology for the widely used Ti6Al4V alloy. Impact process parameters were established and mechanical properties were investigated. In general, static properties were good. Fatigue strength reduced however, although much less so for notched specimens compared to un-notched material. Fatigue crack initiation could be linked to complex features within the (wavy) weld interface associated with the ‘first generation’ impact welding parameters. Next steps are foreseen to improve the fatigue performance.

Two-phase heat transport systems are currently considered for the thermal management of future large power spacecraft. The monitoring of the quality, being the relative vapour mass content, of the two-phase mixture at various locations in the system, is valuable - possibly indispensable - for the proper operation of such a system. This paper reviews concepts for quality monitoring. Only a few concepts turn out to be suitable for spacecraft applications. Promising concepts are based on the capacitance, sonic velocity and index of refraction. These concepts are described and quantitatively analyzed. Applicability, advantages, restrictions and some hardware aspects are discussed.

An introduction is given of phased array beamforming techniques for locating acoustic sources. Starting from basic principles, the Conventional Beamforming technique is described. It is explained how this technique can be applied to wind tunnel measurements. Further, a number of advanced array processing techniques are discussed. One chapter is devoted to the array processing technique for the location of moving sources. This technique can be applied to rotating sources, for example on wind turbine blades, and to source location on aircraft flying over a microphone array.

The Alpha Magnetic Spectrometer AMS-2 is planned for a five years mission as attached payload on ISS, the International Space Station. It is an international experiment searching for anti-matter, dark matter, and missing matter. AMS-2, an improved version of AMS-1 flown on STS 91, consists of various particle detector systems, one of these being the (Silicon) Tracker. The trade-off based choice and the experimental feasibility demonstration of a mechanically pumped two-phase CO2 cooling loop for the Tracker is discussed in detail. The current status and ongoing and planned development activities are discussed.

With the fast growing demand for space based telecommunication capabilities in combination with application of high density electronics, the cooling requirements for future telecommunication satellites is steadily increasing, up to a point that conventional cooling technologies using (loop) heat pipes are no longer ennough to cope with in-orbit load and heat rejection variations, large number of thermal interfaces and testing constraints. To prepare for future high performance cooling requirements, the European Space Agency, ESA initiated the development of a Single-Phase Mechanically Pumped Fluid Loop (MPFL) which was one of the two heat transfer element options for the large Alphabus deployable radiator (see Figure 2).

Free Flight (FF) would permit aircraft to fly preferred routes, and self-separate, with minimal ATC intervention. The controller would be expected to intervene tactically only as necessary to ensure separation. Based on the results of earlier experiments at the NLR, an enhanced ATC display was developed that incorporated airborne-derived conflict detection and resolution information. Trials with controllers demonstrated benefits in terms of monitoring time and performance, as well as in general acceptance. Two important issues were identified for future work: (1) FF training needs and (2) controller responses to abnormal system modes.