BlackBridge owns and operates the RapidEye remote sensing constellation. The 5 satellites are capable of imaging more than 5 million square kilometres a day in 5 spectral bands. The tasking algorithm of the satellites is based on a tile... more
BlackBridge owns and operates the RapidEye remote sensing constellation. The 5 satellites are capable of imaging more than 5 million square kilometres a day in 5 spectral bands. The tasking algorithm of the satellites is based on a tile score system that accounts for the constraint that the RapidEye satellites were not designed to perform roll maneuvers between image takes on the same orbit. A more agile attitude control system, featuring the capability of performing roll maneuvers between individual image takes can further optimize the image collection. This paper shows that such a system grants the tasking process a larger flexibility and enables a faster coverage of the areas of interest. It depicts the impact of the attitude control system agility on the acquisition capacity of remote sensing constellations. Statistical cloud data is used to reproduce the tasking process and to simulate three imaging campaigns of large areas. The paper shows the acquisition capacity of the agile...
There are various robotic On-Orbit Servicing concepts existing, which aim at utilizing inspector satellites for obtaining high-fidelity video feedback from the remote environment. Most of these inspection tasks, which involve proximity... more
There are various robotic On-Orbit Servicing concepts existing, which aim at utilizing inspector satellites for obtaining high-fidelity video feedback from the remote environment. Most of these inspection tasks, which involve proximity operations, can be done autonomously by the spacecraft. However, there are cases such as sensor malfunctions or undefined spacecraft states, in which it seems advantageous to have the possibility of human interaction with the inspector satellite. An operator on ground with the capability of real-time control can complement autonomous operations and add robustness to mission operations. The SPHERES Interact program at the MIT Space Systems Laboratory currently develops concepts for efficient human spacecraft interaction. Using three experimental satellites aboard the International Space Station, a series of tests were executed, which evaluated different approaches and methods. Additionally, using another three of these experimental satellites on the air bearing table at the Space Systems Laboratory, advanced concepts can already be developed and verified on ground. This paper shows experiments, in which the SPHERES at MIT were controlled via a geostationary relay satellite of the European Space Agency (ESA), using a ground station in Germany. It emphasizes the benefits of real-time human spacecraft interaction and describes the design of the associated test environment.
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... Enrico Stoll, Alvar Saenz-Otero, and Brent Tweddle ... The main objective of the SPHERES Goggles is to provide a flight-traceable platform for the development, testing and maturation of computer vision-based navigation algorithms for... more
... Enrico Stoll, Alvar Saenz-Otero, and Brent Tweddle ... The main objective of the SPHERES Goggles is to provide a flight-traceable platform for the development, testing and maturation of computer vision-based navigation algorithms for space-craft proximity operations. ...
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In this paper we present a test environment to test preflight high-fidelity intersatellite communication links on ground. The basic requirements are given by the research project “Telepresence for Space Missions” which is part of a... more
In this paper we present a test environment to test preflight high-fidelity intersatellite communication links on ground. The basic requirements are given by the research project “Telepresence for Space Missions” which is part of a collaborative research centre (SFB 453 – Sonderforschungsbereich) funded by the Deutsche Forschungsgemeinschaft (DFG). The goal of this project is to analyze and test the possibility of establishing a communication link via a geostationary relay satellite having a signal roundtrip time smaller than 0.8 seconds. To establish a link between a Low Earth Orbit (LEO) satellite and a geostationary relay satellite, an Inter Satellite Link (ISL) tracking mechanism to steer the antenna is needed. To verify the functionality of the tracking mechanism, a test bed similar to attitude control system test beds had to be developed at the Institute of Astronautics. Start-ing from the requirements of the attitude control system for an on-orbit servicing mission, a selecti...
Within the last three years, the Joint Space Operations Center (JSpOC) detected 85 close approaches between the RapidEye constellation and secondary space objects. Most of the approaching objects were non-operational, such as debris from... more
Within the last three years, the Joint Space Operations Center (JSpOC) detected 85 close approaches between the RapidEye constellation and secondary space objects. Most of the approaching objects were non-operational, such as debris from the Chinese Fengyun 1C satellite.
The research activities of the Institute of Astronautics (IA) are focused on the analysis of the communication scenario of robotic space missions in detail. That includes also verification of a newly developed Light-weight Inter Satellite... more
The research activities of the Institute of Astronautics (IA) are focused on the analysis of the communication scenario of robotic space missions in detail. That includes also verification of a newly developed Light-weight Inter Satellite Link Antenna (LISA) for small satellites, corresponding steering mechanism and pointing algorithm. The investigation of inter-satellite links is mainly focused on transparent relay satellites which allow data relay between low earth orbit (LEO) and geostationary orbit (GEO) satellites. Therefore the ESA satellite ARTEMIS stands in the main focus of the research work of the Institute. The most important requirement for robotic space missions is given by the time delay between the operator on earth and the manipulator in space. Data processing and data handling strategies are playing also a important role in robotic space mission and are under investigation. The Institute of Astronautics realized a special test environment to investigate these points...
The authority over search and rescue operations (SAR) rests to the so-called rescue coordination center in the Federal Republic of Germany. An essential element for the coordination of SAR operations in general is the communication... more
The authority over search and rescue operations (SAR) rests to the so-called rescue coordination center in the Federal Republic of Germany. An essential element for the coordination of SAR operations in general is the communication between rescue workers and the rescue coordination center. A detailed description of the situation at a remote place, given by the incoming rescue teams, allows the rescue coordination center to get an overview of the scene and to make timely decisions regarding the necessity of a second alarm or calling special forces to the scene. A satellite based extension of the communication chain to, that enables video feedback the rescue coordination center fromon the remote site is a core element of this paper. This extension is realized using a satellite controlled multi-sensor unmanned aerial vehicle (UAV). A radio controlled copter is used that permits telepresent operations and thus, enables the rescue control center to initiate autonomous procedures at the s...
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ABSTRACT Upcoming space missions utilizing hyperspectral or other high-resolution sensors will generate a vast amount of data in orbit. The average communication duration between a spacecraft in low Earth orbit (LEO) to a dedicated ground... more
ABSTRACT Upcoming space missions utilizing hyperspectral or other high-resolution sensors will generate a vast amount of data in orbit. The average communication duration between a spacecraft in low Earth orbit (LEO) to a dedicated ground station is short and in addition, due to the high amount of data to be transferred at link times, a high-performance communication system on board of the satellite is indispensable.A solution that provides longer acquisition times with the ground station is to employ a high data-rate inter-satellite link to a geostationary relay satellite, which requires a flat, compact, steerable, light-weight yet robust antenna. Such an antenna system (antenna module plus pointing module) was developed for S-Band at the Institute of Astronautics (Technische Universität München), in cooperation with German space companies, research institutes and the German Aerospace Center (DLR). Its successful operation via the geostationary relay satellite Artemis was demonstrated in cooperation with ESA in 2007.This paper describes the evaluation of an antenna system in the Ka-Band, as a successor to be developed in the next two years for high data rates and the various applications of such an antenna system.