A simplified approach to analyze the space debris evolution in the low earth orbit

During the past 60 years the number of objects on Earth orbits has increased. So has the risk of collisions, which is likely to be the main driver for space debris generation in the future. This is important, for example, in densely populated regions like the sun-synchronous orbit at around 800 km altitude. In order to predict the future development of the debris environment numerical simulations can be used. These simulations are usually based on initial assumptions like the launch rate, the probability distribution of success of post mission disposal measures and the likelihood for catastrophic collisions. The computationally expensive Monte-Carlo method is employed for the random sampling of the defined events. Additionally, a propagator needs to process the objects to determine potential collision partners, increasing the demand for computing power even further. In this paper an analytical model is presented, which is based on source and sink mechanisms, like launches, collisions and explosions. In this approach different altitude shells and diameter bins, as well as four different object classes for intact objects and fragments, each on circular and eccentric orbits are considered. By using pre-computed tables for orbital lifetimes and decay rates, both the computational effort and complexity of the model are decreased. The model can be adjusted to reflect different forecasts by altering the decay and collision rates. The paper concludes by showing preliminary results and a discussion of the generic approach, which allows the model to be fitted against more computationally expensive Monte-Carlo simulations

HVI-test setup for debris detector verification

Risk assessment concerning impacting space debris or micrometeoroids with spacecraft or payloads can be performed by using environmental models such as MASTER (ESA) or ORDEM (NASA). The validation of such models is performed by comparison of simulated results with measured data. Such data can be obtained from ground-based or space-based radars or telescopes, or by analysis of space hardware (e.g. Hubble Space Telescope, Space Shuttle Windows), which are retrieved from orbit. An additional data source is in-situ impact detectors, which are purposed for the collection of space debris and micrometeoroids impact data. In comparison to the impact data gained by analysis of the retrieved surfaces, the detected data contains additional information regarding impact time and orbit. In the past, many such in-situ detectors have been developed, with different measurement methods for the identification and classification of impacting objects. However, existing detectors have a drawback in terms of data acquisition. Generally the detection area is small, limiting the collected data as the number of recorded impacts has a linear dependence to the exposed area. An innovative impact detector concept is currently under development at the German Aerospace Centre (DLR) in Bremen, in order to increase the surface area while preserving the advantages offered by dedicated in-situ impact detectors. The Solar Generator based Impact Detector (SOLID) is not an add-on component on the spacecraft, making it different to all previous impact detectors. SOLID utilises existing subsystems of the spacecraft and adapts them for impact detection purposes. Solar generators require large panel surfaces in order to provide the spacecraft with sufficient energy. Therefore, the spacecraft solar panels provide a perfect opportunity for application as impact detectors. Employment of the SOLID method in several spacecraft in various orbits would serve to significantly increase the spatial coverage concerning space debris and micrometeoroids. In this way, the SOLID method will allow the generation of a large amount of impact data for environmental model validation. The ground verification of the SOLID method was performed at Fraunhofer EMI. For this purpose, a test model was developed. This paper focuses on the test methodology and development of the Hypervelocity Impact (HVI) test setup, including pretesting at the German Aerospace Centre (DLR), Bremen. Foreseen hardware and software for the automatic damage assessment of the detector after the impact are also presented

DEVELOPMENT OF A NEW MULTI-PURPOSE UAS FOR SCIENTIFIC APPLICATION

Project SUBVENTO is a joint research project of the research facility Technische Universität Braunschweig and the industry partner BBR - Baudis Bergmann Rösch Verkehrstechnik GmbH in close cooperation with the German Federal Agency for Technical Relief (THW). The Project is funded within the European Regional Development Fund (EFRE) allocated by the European Union. Therein an integrated system for the fast and automated remote detection of heat sources using an infrared camera is being developed. For a precise detection of fires or persons a very accurate navigation system including the algorithms and the hardware is required. Furthermore additional sensors like a multispectral camera applicable in small unmanned aerial vehicles (UAVs) should be implemented. Since the mentioned sensor equipment exceeds the current UAVs' payload limit, a new Carolo type aircraft with a wingspan of 3.6 m is designed. It has an increased payload capability and an extended flight time. This is possible due to an optimized aerodynamic layout and a high efficient propulsion system. Das Projekt SUBVENTO ist ein Verbund-Forschungsprojekt der Technischen Universität Braunschweig sowie dem Industriepartner BBR – Baudis Bergmann Rösch Verkehrstechnik GmbH und wird in enger Zusammenarbeit mit dem Deutschen Technischen Hilfswerk (THW) durchgeführt. Das Projekt wird über den Europäischen Fond zur regionalen Entwicklung (EFRE) durch die Europäische Union gefördert. In diesem Projekt wird ein integriertes System zur schnellen und automatischen Detektion von Hitzequellen mittels einer Infrarotkamera entwickelt. Zur genauen Positionsbestimmung der Feuer oder Personen ist ein präzises Navigationssystem, bestehend aus den Navigationsalgorithmen und der verwendeten Hardware, nötig. Des Weiteren sollen zusätzliche für Unbemannte Flugzeuge (UAVs) geeignete Sensoren, wie beispielsweise eine Multispektralkamera integriert werden. Da dieses Sensorpaket die Nutzlast der bisher verfügbaren Flugzeuge der Carolo Familie übersteigt, wird ein neues Muster mit einer Spannweite von 3,6 m entwickelt. Durch eine verbesserte aerodynamische Auslegung und ein effizientes Antriebssystem wird die Flugzeit und Nutzlastkapazität gesteigert