Operations System vs. Operating System: Towards a Ground System Supporting Satellite Application Programming

The term operating system refers to a software component, which traditionally controls the resources and the processes of a computer, and by providing the appropriate interfaces allows for the implementation of custom user applications. This is a common definition, working very well for ordinary computer systems. Yet, what if the operating system and a corresponding application are physically separated, because the computer is within a satellite in space, while the user program is executed on ground? Then, capabilities must be created to connect both, which is of course complicated by the natural boundaries in satellite communication, for example the limited satellite contact times. Over the past decades, several systems have been developed, which are capable of managing satellite resources and the mission schedule from ground. Although this covers quite well the purpose of an operating system, other terms have evolved in this domain: operations system, ground system, mission control system, ground data handling, etc. The problem though is, those systems primarily focus on the exchange of data and satellite TM/TC, rather than the actual control process. This creates an artificial barrier between ground and space, which harms the development capabilities for ground based satellite applications. This paper introduces a novel approach for an operations system architecture, which can be considered as a ground extension of the satellite’s operating system. This approach shall not break with the existing conventions and definitions, especially in terms of operating systems, but shall introduce a new view on satellite operations. In a layered, functional software architecture, the operating system is the lowest layer between the hardware and the application. Through the definition of the appropriate interfaces in the ground system, a software architecture can be created that actively supports outsourcing parts of the satellite control process to ground. The proposed approach has great potential for various applications in satellite operations. It supports the implementation of automatic system control processes, the implementation of custom payload applications, and the integration of respective activities into the satellite schedule. As applications and operators interact with a verified schedule, and operations is thus no longer limited to low-level commanding, the approach further reduces the risk of the mission being jeopardized by human mistake

Update on DLR's OSIRIS program and first results of OSIRISv1 on Flying Laptop

Optical satellite links have gained increasing attention throughout the last years. Especially for the application of optical satellite downlinks. Within the OSIRIS program, DLR's Institute of Communications and Navigation develops optical terminals and systems which are optimized for small satellites. After the successful qualification and launch of two precursor terminals, DLR currently develops OSIRISv3, a 3rd generation OSIRIS terminal with up to 10 Gbps downlink rate, and OSIRIS4Cubesat, a miniaturized version optimized for Cubesat Applications. The University of Stuttgart's Institute of Space Systems develops small satellites, which are used to demonstrate novel technologies in the Space domain. Together, DLR and University of Stuttgart integrated the first OSIRIS generation onboard the Flying Laptop satellite, which was launched in July 2017 and has been successfully operated since. This paper will give an overview about DLR's OSIRIS program. Furthermore, it will show first results of OSIRISv1 on Flying Laptop. Therefore, the Flying Laptop satellite and OSIRISv1 will be explained. Preliminary results from the validation campaign, where optical downlinks have been demonstrated, will be given. © 2019 SPIE. Downloading of the abstract is permitted for personal use only

Analysis of collision avoidance manoeuvres using aerodynamic drag for the Flying Laptop satellite

Collision avoidance is a topic of growing importance for any satellite orbiting Earth. Especially those satellites without thrusting capabilities face the problem of not being able to perform impulsive collision avoidance manoeuvres. For satellites in Low Earth Orbits, though, perturbing accelerations due to aerodynamic drag may be used to influence their trajectories, thus offering a possibility to avoid collisions without consuming propellant. Here, this manoeuvring option is investigated for the satellite Flying Laptop of the University of Stuttgart, which orbits the Earth at approximately 600 km. In a first step, the satellite is aerodynamically analysed making use of the tool ADBSat. By employing an analytic equation from literature, in-track separation distances can then be derived following a variation of the ballistic coefficient through a change in attitude. A further examination of the achievable separation distances proves the feasibility of aerodynamic collision avoidance manoeuvres for the Flying Laptop for moderate and high solar and geomagnetic activity. The predicted separation distances are further compared to flight data, where the principle effect of the manoeuvre on the satellite trajectory becomes visible. The results suggest an applicability of collision avoidance manoeuvres for all satellites in comparable and especially in lower orbits than the Flying Laptop, which are able to vary their ballistic coefficient.Comment: 12 pages, 13 figures. arXiv admin note: text overlap with arXiv:2302.0689

Optical Data Downlinks from OSIRIS on Flying Laptop Satellite

Optical High-Speed Telemetry Downlinks for high data volumes from Earth Observation Satellites in Low Earth Orbit (OLEODL) is currently developing into a future standard in high-speed space communications. The German Aerospace Center (DLR) Institute for Communications and Navigation (IKN) has developed the miniaturized data downlink terminal OSIRIS (Optical Space InfraRed downlInk System) for space-to-ground links over LEO-distances, and has proven its Performance by pre-operational downlinks from the University of Stuttgart Flying-Laptop (FLP) satellite

Downlink communication experiments with OSIRISv1 laser terminal onboard Flying Laptop satellite

Downlink measurement campaigns from the optical downlink terminal OSIRISv1 onboard the LEO satellite Flying Laptop were carried out with the French Observatoire de la Cote d Azur and with two Optical Ground Stations of the German Aerospace Center. On/off keyed data at 39 Mb/s were modulated on the laser signal, and according telecom reception was performed by the ground stations. The pointing of the laser terminal was achieved by open-loop body pointing of the satellite orientation, with its star sensor as attitude control signal. We report here on the measurements and investigations of the downlink signal and the data transmission

Optical bench development for laser communication OSIRIS mission at Grasse (France) station

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