S. Radu
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10 records found
1
The paper presents the initial outcomes of a project, currently ongoing under the supervision of the European Space Agency, having the main objective to specify and design a Fault Detection Isolation and Recovery (FDIR) system by making use of relevant RAMS (Reliability, Availability, Maintainability, Safety) analyses for missions in non-deterministic environment with limited resources. The initial project tasks have been to select a study case represented by a CubeSat complex mission, analyse in detail both its mission and system requirements and, based on them, define a set of relevant RAMS analyses to be carried out in the second phase of the project, as inputs for the development of a FDIR concept aimed at a careful balance of the limited spacecraft resources in case of critical failures. Two possible study cases have been identified: LUMIO, a 12U CubeSat mission for the observation of micro-meteoroid impacts on the Lunar farside, and M-ARGO, a 12U deep-space CubeSat which will rendezvous with a near-Earth asteroid and characterize its physical properties for the presence of in-situ resources. Although both missions are characterized by a high level of autonomy and complexity in a harsh environment, LUMIO has been eventually selected as study case for the project. In the paper, the challenges and features of this mission are shortly presented. The specificities of the RAMS analysis and FDIR concept for this specific class of small satellite missions (including the selected study case) are highlighted in the paper, looking in particular at aspects such as the improvement of reliability while maintaining the CubeSat philosophy, the tuning of mission and system requirements in view of facilitating the design and implementation of the FDIR concept, and the current gaps within the RAMS/FDIR body of knowledge. The conclusions drawn during this first project phase provide a real view of how systems engineering must work in tandem with RAMS analyses and FDIR to achieve a more robust and functional mission architecture, thus improving the mission reliability.
PocketQubes are a form factor of highly miniaturized satellites with a body of one or more cubic units of 5 cm. In this paper, the characteristics of PocketQubes in terms of their constraints and their (potential) utility are treated. To avoid space debris and limit collision risk, the orbits of PocketQubes need to be constraint. An analysis of orbital decay characteristics has been carried out which, considering existing space regulations and a pro-active attitude, PocketQubes should preferably be launched in low Earth orbits below 400 km altitude. Due to technical constraints, such as form factor, power and attitude control, the domain of applications for single PocketQube missions is limited. Still, they can act as low-cost training and technology demonstration platforms. To make PocketQubes an attractive platform for other types of missions, not only the launch cost, but also the development, production and operations cost should be significantly lower than CubeSats. When the PocketQube platform matures and produced in high numbers, networks of PocketQubes can enable new applications. Applications considered feasible are in the field of (but not limited to) continuous surveillance using optical instruments, gravity field monitoring using precise orbit determination, in-situ measurements of the space environment, low data rate or bandwidth communication services and inexpensive probes around other celestial bodies.
One of the in-situ characterization technologies currently under investigation at Delft University of Technology is the so-called “Smart-Net”, which makes use of the PocketQube satellite platform developed by the Space Systems Engineering group. PocketQubes are cube-shaped platform based on 50 mm3 units with a mass of less than 250 g each. Delft University of Technology has embarked in the design and development of this class of picosatellites in order to further advance its research on satellite miniaturization: a PocketQube, by definition, has 8 times less volume when compared to a CubeSat. Potentially, deep space and interplanetary missions can gain even more advantage from the use of large networks of these very small satellites, by reducing costs, improving redundancy and assure high scientific return through their use in big numbers.
In the innovative Smart-Net, a number of PocketQube devices, equipped with a full suite of sensors and radio beacons, are used to sense the surface of an asteroid, measure its temperatures in various locations and its dynamics and rotational speed, while directly transmitting the gathered scientific information to the Earth. These PocketQube units represent the nodes of a net that can fully wrap and cover the entire surface of a small asteroid up to a few meters in size, with the net wires representing at the same time an antenna for direct communication from the PocketQubes to the Earth or a mother spacecraft. The PocketQube units are also equipped with hooks, to increase the chances for anchoring a body with very low gravity field. This paper presents the preliminary design of the Smart-Net and the expected challenges for its development and in-situ validation in an actual space mission.
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One of the in-situ characterization technologies currently under investigation at Delft University of Technology is the so-called “Smart-Net”, which makes use of the PocketQube satellite platform developed by the Space Systems Engineering group. PocketQubes are cube-shaped platform based on 50 mm3 units with a mass of less than 250 g each. Delft University of Technology has embarked in the design and development of this class of picosatellites in order to further advance its research on satellite miniaturization: a PocketQube, by definition, has 8 times less volume when compared to a CubeSat. Potentially, deep space and interplanetary missions can gain even more advantage from the use of large networks of these very small satellites, by reducing costs, improving redundancy and assure high scientific return through their use in big numbers.
In the innovative Smart-Net, a number of PocketQube devices, equipped with a full suite of sensors and radio beacons, are used to sense the surface of an asteroid, measure its temperatures in various locations and its dynamics and rotational speed, while directly transmitting the gathered scientific information to the Earth. These PocketQube units represent the nodes of a net that can fully wrap and cover the entire surface of a small asteroid up to a few meters in size, with the net wires representing at the same time an antenna for direct communication from the PocketQubes to the Earth or a mother spacecraft. The PocketQube units are also equipped with hooks, to increase the chances for anchoring a body with very low gravity field. This paper presents the preliminary design of the Smart-Net and the expected challenges for its development and in-situ validation in an actual space mission.
The new satellite platform, called Delfi-PQ, inspired by the success of previous Delfi satellite projects is seen as an opportunity for innovation and offers research challenges in the miniaturization field of systems and components. The focus of this paper is to highlight those innovations and challenges, and to communicate the progress that has been made with respect to building a core platform and standardized bus.
The mission of Delfi-PQ is to demonstrate a reliable core bus and outer structure for a three unit PocketQube that shall be tested in flight as a first iteration of a series of PocketQubes to be developed by Delft University of Technology. The core bus shall fit in one unit - 1P (50x50x50mm), having as aim that after further miniaturization and optimization, the second unit shall contain an advanced subsystem (e.g. advanced Attitude Determination and Control System - ADCS) and the third unit shall consist of a scientific payload (e.g micro-propulsion, lensless camera). For Delfi-PQ, the focus was on the miniaturization process and on the structure of the PocketQube. The core platform of the first Delfi-PQ consists of the Electrical Power System (including two 3.7V batteries and solar panels with two cells/each X-Y face), On-board Computer, Communications System, ADCS (including two magnetorquers and three magnetometers), as well as: temperature sensors and two different sensors for assessing the rotational speed of the PocketQube. ...
The new satellite platform, called Delfi-PQ, inspired by the success of previous Delfi satellite projects is seen as an opportunity for innovation and offers research challenges in the miniaturization field of systems and components. The focus of this paper is to highlight those innovations and challenges, and to communicate the progress that has been made with respect to building a core platform and standardized bus.
The mission of Delfi-PQ is to demonstrate a reliable core bus and outer structure for a three unit PocketQube that shall be tested in flight as a first iteration of a series of PocketQubes to be developed by Delft University of Technology. The core bus shall fit in one unit - 1P (50x50x50mm), having as aim that after further miniaturization and optimization, the second unit shall contain an advanced subsystem (e.g. advanced Attitude Determination and Control System - ADCS) and the third unit shall consist of a scientific payload (e.g micro-propulsion, lensless camera). For Delfi-PQ, the focus was on the miniaturization process and on the structure of the PocketQube. The core platform of the first Delfi-PQ consists of the Electrical Power System (including two 3.7V batteries and solar panels with two cells/each X-Y face), On-board Computer, Communications System, ADCS (including two magnetorquers and three magnetometers), as well as: temperature sensors and two different sensors for assessing the rotational speed of the PocketQube.