J. Bouwmeester
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33 records found
1
AltiCube+
A low-cost long fixed-baseline radar altimeter solution based on cubesats on-orbit assembly
One of the most ambitious goals of modern astronomy is to uncover signs of extraterrestrial biological activity, primarily achieved through spectroscopic analysis of light emitted by exoplanets to identify specific atmospheric molecules. Most exoplanets are indirectly identified through techniques like transit or Doppler shift of the host star's flux. Long-term surveys have yielded statistical insights into the occurrence rates of different planet types based on factors such as radius/mass, orbital period, and the spectral type of the host star, initial estimates of terrestrial planets within the habitable zone have also emerged. However, the difficulty of detecting light from these exoplanets leaves much unknown about their nature, formation, and evolution. As the number of rocky exoplanets around nearby stars rises, questions about their atmospheric composition, evolutionary trajectory, and habitability increase. Direct measurement of an cxoplanct's atmospheric composition through its spectral signature in the infrared can provide answers. Measuring the infrared spectrum of these planets poses significant challenges due to the star/planet contrast and very small angular separation from their host stars. Previous research showed that space-based telescopes are mandatory, and unless large primary mirrors (>30m in diameter) can be sent into space, intcrfcrometric techniques become essential. Combining light from distant telescopes with interferometric techniques allows access to information at minimal angular separation, operating within the diffraction limit of individual telescopes. Successful demonstrations of on-ground nulling interferometry open a new era for such space-based missions. They are vital to sidestep and tackle these scientific questions. We recently initiated a new study with the European Space Agency to explore the design parameters and the performances related to an interferometric concept based on a single spacecraft and sparse multiple sub-apertures. Launch constraints are linked to the use of an Ariane 6 launch vehicle. Our parametric study covers a range of 1-4 m for the diameter of the telescope and a 10-60 m baseline. The most promising concept working in the infrared range (3-20μm) will be highlighted. This study is conducted by TUDelft in cooperation with KULeuven, CSL/ULiege, and Amos with the support of the European Space Agency.
Mctamatcrials and mctasurfaccs hold significant promise for space applications due to their compactness and lightweight characteristics. These devices use nanostructures embedded in their flat surfaces to manipulate the electromagnetic field for various purposes. Among their potential applications, metalenses stand out for their prospective role in the next generation of optical instruments deployed in space. Specifically, they offer considerable advantages for free space optical and quantum communications terminals. In intersatellite free space optical communication links, transmitter pointing errors degrade the performance of the link. Nevertheless, optimizing the shape of the transmitted beam through a metalens can improve the communication link performance. In this study, we delve into the application of metalenses for shaping laser beams in intersatellite optical communication scenarios. We present the preliminary design of the metalens and analyze its performance through numerical simulations, analyzing its feasibility and potential in space-based optical communications.
imaging spectroscopy. The goal is to address and further improve the observed spectral signatures of different plastics by imaging the observed scenery. In order to distinguish between these different kinds of plastics, a dedicated optical filtering system with a high resolution and revisit time has to be designed. Therefore, the concept is based on an Acousto-Optic Tunable Filter (AOTF), specifically designed for remote sensing and imaging. In order to achieve a high temporal resolution, being able to capture the evolution and movement of plastic in the oceans, a constellation of satellites are foreseen. Therefore, a low flying platform and deployable optics are introduced. Flying at 300 km altitude instead of a typical > 600 km for Earth observation satellites, reduces the required imaging aperture. ...
imaging spectroscopy. The goal is to address and further improve the observed spectral signatures of different plastics by imaging the observed scenery. In order to distinguish between these different kinds of plastics, a dedicated optical filtering system with a high resolution and revisit time has to be designed. Therefore, the concept is based on an Acousto-Optic Tunable Filter (AOTF), specifically designed for remote sensing and imaging. In order to achieve a high temporal resolution, being able to capture the evolution and movement of plastic in the oceans, a constellation of satellites are foreseen. Therefore, a low flying platform and deployable optics are introduced. Flying at 300 km altitude instead of a typical > 600 km for Earth observation satellites, reduces the required imaging aperture.
AltiCube+
A Low-Cost Long Fixed-Baseline Radar Altimeter Solution Based On CubeSats On-Orbit Assembly
Radar interferoinetry can be used to obtain sub-kilometer resolution over a swath at the expense of additional transmit power and a sufficiently long baseline to accommodate at least two antennas. This paper reports an innovative concept called AltiCube+, a low-cost long fixed-baseline interferometric radar altimeter based on CubeSats on-orbit assembly. The AltiCube+ concept consists of multiple 16U CubeSats, After an early operation and commissioning phase, these CubeSats will perform autonomous rendezvous and docking with each other via deployable booms to establish a long fixed-baseline, and then deploy antennas for an interferometric altimeter configuration. The uniqueness of AltiCube+ is on the potential scientific opportunities brought by two left and right looking interferometric altimeters with around 6 meter baseline (total system length is more than 8 m) and the sustainability due to its significantly low cost and short development lifecycle. If budget allows, multiple AltiCube+ systems with same or different altimetry capabilities can form a constellation to dramatically reduce the revisit time and, therefore, provide much better spatiotemporal coverage.
This chapter provides an overview of the command and data handling system (CDHS) in small satellites and CubeSats. The chapter presents first analysis of radiation effects, specifically targeted at this subsystem, to justify components and architecture choices. Improvements in radiation testing strategies are also presented, specifically for small satellites. State-of-the-art components are then presented, providing an overview of the current market and the most common architectures. An overview of past and current missions is also presented, providing a clear mapping of the presented state-of-the-art components and architectures to guide future designs. High-level design considerations are also presented to help the reader follow some of the current trends in the sector. This chapter, overall, aims at presenting the most common approaches for the CDHS system and comparing this with traditional satellites, showing where the main differences lay with component selection and testing strategies being the fundamental points driving the architecture choices.
The Architecture of CubeSats and PocketQubes
Towards a Lean and Reliable Implementation of Subsystems and Their Interfaces
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.
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.