Cube Laser Communication Terminal state of the Art

Based on the increasing need for higher data rates in CubeSat missions primarily for Earth observation and communication missions mainly focused on Direct-to-Earth (DTE) applications, DLR started the development of a highly compact laser communication payload for CubeSats. In parallel TESAT has used its experience for preparing and developing this technology for volume production. At the same time to ensure the compatibility with the ground stations, DLR started and lead the CCSDS working group for Optical On-Off-Keying (O3K) to further extend the commercial use of CubeLCT terminals. This cooperation between industry and research center has been very successful. The PIXL-1 mission was accomplished in a very agile new space approach, developing and demonstrating the technology in record time. Moreover, in order to enable the potential customers to deploy a complete end-to-end system, TESAT in cooperation with GSOC has specified the interface requirements for developing the first demonstrator for DTE optical system mission planning, mainly focused on the link planning challenges. This concept can be applied to current missions, and allows identifying the needs also for further applications. In addition to DTE links, the increasing demand for higher data rates and low latency communication in upcoming constellations of CubeSats also drives the need to extend the CubeLCT terminal with Inter-Satellite-Linkfunctionality. In continuation to the first development, IKN, RSC3 and TESAT, are currently developing a CubeLCT for intra-plane communication capable of transferring 100 Mbps over 1800 km. The upcoming challenges in operation of inter-satellite-links on CubeSats combined with the possibilities of enabling DTE are also covered in this paper

Survey and simulation of space debris using EISCAT UHF

This thesis starts with a review of the evolution of space debris, what is consists of, how it is made, how it is detected and tracked, and why it is such an important topic. Some of the worst collisions have contributed to causing 49% of the total space debris. If the launch rate continues, the "Kessler Syndrome" might become a reality destroying our future outlook for space communication and exploration. Furthermore, a deeper look at the contents is done and what is the impact of these hypervelocity objects. Highly-advanced ground surveillance systems are used to track and catalog the space debris stationed around the globe, and highly sophisticated space debris models are used to estimate the density of the total space debris population in all sizes, shapes and compositions. After 60 years in space, a lot of space debris has accumulated, resulting in a large increase of density in the polar regions. However, objects below 10 cm are not easily detected, but EISCAT UHF is capable detecting the sizes below 10 cm and down to 1 cm by using beampark experiments, its location makes it suitable for detecting polar region debris. The data is then used to confirm the catalog and the models. A 24-hour beampark experiment was done on 4th of January 2018 simultaneously at Tromsø and Svalbard, specifically for this thesis. It statistically measured the range, the Doppler velocity, and the echo strength of space debris. An inversion of apogee and inclination was then done by using these parameters. A modelling of a beampark experiment was simulated, propagating objects through the EISCAT UHF beam. It extracted the data from the ESA MASTER model and the output was the number of detections per day. A comparison of the beampark experiment 2018 campaign with the simulation model indicated that the simplified model shows good correlation with the observations

The data concept behind the data: From metadata models and labelling schemes towards a generic spectral library

Spectral libraries play a major role in imaging spectroscopy. They are commonly used to store end-member and spectrally pure material spectra, which are primarily used for mapping or unmixing purposes. However, the development of spectral libraries is time consuming and usually sensor and site dependent. Spectral libraries are therefore often developed, used and tailored only for a specific case study and only for one sensor. Multi-sensor and multi-site use of spectral libraries is difficult and requires technical effort for adaptation, transformation, and data harmonization steps. Especially the huge amount of urban material specifications and its spectral variations hamper the setup of a complete spectral library consisting of all available urban material spectra. By a combined use of different urban spectral libraries, besides the improvement of spectral inter- and intra-class variability, missing material spectra could be considered with respect to a multi-sensor/ -site use. Publicly available spectral libraries mostly lack the metadata information that is essential for describing spectra acquisition and sampling background, and can serve to some extent as a measure of quality and reliability of the spectra and the entire library itself. In the GenLib project, a concept for a generic, multi-site and multi-sensor usable spectral library for image spectra on the urban focus was developed. This presentation will introduce a 1) unified, easy-to-understand hierarchical labeling scheme combined with 2) a comprehensive metadata concept that is 3) implemented in the SPECCHIO spectral information system to promote the setup and usability of a generic urban spectral library (GUSL). The labelling scheme was developed to ensure the translation of individual spectral libraries with their own labelling schemes and their usually varying level of details into the GUSL framework. It is based on a modified version of the EAGLE classification concept by combining land use, land cover, land characteristics and spectral characteristics. The metadata concept consists of 59 mandatory and optional attributes that are intended to specify the spatial context, spectral library information, references, accessibility, calibration, preprocessing steps, and spectra specific information describing library spectra implemented in the GUSL. It was developed on the basis of existing metadata concepts and was subject of an expert survey. The metadata concept and the labelling scheme are implemented in the spectral information system SPECCHIO, which is used for sharing and holding GUSL spectra. It allows easy implementation of spectra as well as their specification with the proposed metadata information to extend the GUSL. Therefore, the proposed data model represents a first fundamental step towards a generic usable and continuously expandable spectral library for urban areas. The metadata concept and the labelling scheme also build the basis for the necessary adaptation and transformation steps of the GUSL in order to use it entirely or in excerpts for further multi-site and multi-sensor applications

Automation of Operation and Testing for European Space Agency's OPS-SAT Mission

This thesis presents a solution for mission operation automation in European Space Agency's (ESA) OPS-SAT mission. To achieve this, the ESA internal mission automation system (MATIS) in combination with the mission control software (SCOS) are used. They control the satellite and all ground peripherals and programmes to enable fully automated and unsupervised satellite passes. The goal of this work is the transition from the existing manual operation, with a human operator watching over and controlling all systems, to an automated system. This system supports the operation engineer and replaces the operator himself. A large section of this thesis consists of the setup, configuration, integration of all programmes and virtual machines and testing of the MATIS software, as well as the Service Management Framework (SMF) which connects MATIS to non-MATIS applications like SCOS. During testing, a lot of problems could be identified, not only OPS-SAT specific ones, but also general problems applying to all missions that consider using MATIS for future operation automation. These findings and bugs discovered during testing are reported to the responsible authorities and presented in this work. Further features of this thesis are the elaborations of the mission operation automation concept and the satellite pass concept, providing an in-depth view of the automation and passes of OPS-SAT as well as the general concepts and thoughts, which can be used by other missions to accelerate integration. An additional key feature of this thesis is the newly developed standard for operation notation in Excel, which has been achieved in close cooperation with the operation engineer. Furthermore, to accelerate the process of switching from manual to automated procedures, several converters have been developed iteratively with the new standard. These converters allow fast transformation from Excel to the procedure programming language called PLUTO used by MATIS. Not only do the results and converters of this work accelerate the procedure integration by 80%, they also deliver a more stable mission automation system that can be used by other missions as well. Operation automation reduces the operational costs for satellites and space missions significantly, as well as reducing the human error to a minimum. Therefore, this thesis is the first step towards a future with complete automation in the area of satellite operations. Without this automation, future satellite cluster configurations, like Starlink from SpaceX, will not be possible to put into practice, due to their high complexity, exceeding the comprehensibility and reaction time of humans

Potencial das capacidades de observação da terra em África para melhorar a sustentabilidade ambiental da região

Duas décadas antes da publicação do “Relatório Brundtland”, a sustentabilidade ambiental já recorria a imagens de Observação da Terra (OT), recolhidas por satélites artificiais, úteis para meteorologia, monitorizar a poluição, desertificação, e alterações climáticas. África deu os primeiros passos no Espaço nos anos 70. Os países africanos investiram já mais de 300M de dólares em satélites de OT, e alguns constroem os seus próprios CubeSat. Ao contrário da Europa, nunca se materializou uma Agência Espacial que unisse esforços dos países africanos. Muitos stakeholders de ambiente africanos usam dados espaciais, e era importante perceber porque não fruiu ainda uma iniciativa espacial multinacional, e como poderia semelhante cooperação servir a sustentabilidade ambiental naquela região. A metodologia seguida aliou a pesquisa bibliográfica a um inquérito feito a entidades africanas dos setores de Espaço e de ambiente. Na primeira fase analisaram-se as 24 iniciativas espaciais africanas. Foram classificadas segundo uma escala proposta pelo autor, que dá primazia ao conhecimento, sobre a industrialização e orçamento. Concluiu-se que a África do Sul, a Argélia, a Nigéria, e Egito são os maiores casos de sucesso. Sendo evidente que as aplicações de OT têm impacto positivo na sustentabilidade ambiental, em África e noutras regiões do globo, foi realizado um inquérito (segunda fase) que obteve 95 respostas. Os inquiridos conhecem iniciativas espaciais, sobretudo não africanas, valorizam o Espaço como resposta aos desafios da sustentabilidade ambiental, e creem ser prioritário o conhecimento versus tecnologia. A casuística dos insucessos de iniciativas multinacionais africanas, torna irrealista esse tipo cooperação em Espaço, e impossível de emular o modelo da Agência Espacial Europeia. Propõe-se então, o roadmap para ajudar atores africanos a melhor guiar os seus esforços espaciais para sustentabilidade ambiental. O roadmap abrange boas práticas para iniciativas espaciais nacionais e multinacionais africanas, e o desenvolvimento local de aplicações de OT. São enfatizadas as potencialidades dos drones e das tendências “New Space”. Considera-se que os atores de Espaço africanos poderão alcançar mais sucesso investindo na educação e em políticas de dados abertas para a produção de informação pertinente aos stakeholders do ambiente.Already two decades before the “Brundtland” Report” was published, environmental sustainability was being served by Earth Observation (EO) images, collected by man-made satellites, and useful for meteorology, monitoring pollution, desertification and climate change. Africa took its first step into space in the 1970s. Over 700M USD have been since invested in EO satellites by African Nations, some building CubeSats on their own. Unlike in Europe, a Space Agency that would have joined African Nations’ forces never materialized. However, many environmental stakeholders in Africa use space data, and it is important to grasp why a multinational space initiative has not come into fruition, and how such cooperation could serve environmental sustainability in the region. The methodology followed combined bibliographic research and a survey made with African entities from the space and environment sectors. In the first phase, the 24 African space initiatives were analysed. This classification was made with a scale proposed by the author, which over emphasizes know-how over industrialisation and budget. Algeria, Nigeria, Egypt and South Africa were graded as the most successful. Evidence showing that EO applications can leave a positive impact on environmental sustainability in Africa and other regions in the world, a survey (undertaken in the second phase) gathered 95 responses, covering 34 of the 54 African nations. The responders were found to be knowledgeable about space initiatives, especially non-African, value space as a response to environmental sustainability challenges, and believe know-how should be a priority over technology. The underlying reasons why multinational initiatives have not succeeded in Africa, makes such type of cooperation unrealistic in space, and impossible to emulate the European Space Agency model. A roadmap is then devised to help African actors guide their space efforts towards environmental sustainability. This roadmap covers best practices for national and multinational African space initiatives, and the development of OT applications. The potential offered by drones and New Space trends are emphasized. It is considered that African space actors can achieve more success by investing in education and open data policies in order to produce information pertinent to environment stakeholders