Browsing by Author "Kingston, Jenny"

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    Development of commercial drag-augmentation systems for small satellites
    (ESA Space Debris Office, 2017-06-30) Palla, Chiara; Kingston, Jenny; Hobbs, Stephen
    In the framework of the ESA CleanSat programme Cranfield University is developing a family of drag augmentation system (DAS) modules to enable small satellites in Low Earth Orbit (LEO) to comply with space debris mitigation requirements. There are currently two mature Cranfield DAS designs based on deployable Kapton sails using stored energy for deployment. One concept is Icarus and it is currently on-board the UK’s TechDemoSat-1 (launched 8 July 2014) and Carbonite-1 spacecraft (launched 10 July 2015). The second concept is the de-orbit mechanism (DOM) module, which is due to fly as technological demonstrator on the upcoming ESA ESEO mission. The key drivers used during the design process were: low cost, low mass, easy testability, safety, reliability, and avoidance of additional debris production. These drivers matched with top-level requirements, from a potential customers perspective (e.g.: satellite integrators), which were defined during the CleanSat study. Other relevant requirements for the DAS included demisability, performance (in terms of orbital decay), area-to-mass ratio, functionality, lifetime, and environment compatibility. This paper discusses the compliance of the Cranfield DAS designs with the identified requirements, and illustrates the scalability via application to several case study missions (500 kg and 200 kg LEO satellites). The two most challenging aspects to assess were compliance with the lifetime required for storage on ground and pre-deployment on orbit, and the effect of the orbital environment (radiation, ATOX, debris) on the sail. The study has provided useful input to explore new concepts based on the heritage designs; these concepts are evolutions of the DOM unit and hybrid designs. The hybrid design combines aspects of the Icarus and the DOM concepts to reduce the limitations of the respective individual devices and improve scalability, adaptability and manufacturability. In addition, this work is helping to achieve commercial readiness for the technology. This will enable development of a commercial DAS offering that will be an attractive solution for small satellite integrators, allowing them to meet debris mitigation requirements.
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    Development of drag augmentation systems for de-orbiting small satellites
    (2017-06) Palla, Chiara; Kingston, Jenny
    The adoption of the ISO 24113 by ESA in 2014 has set an important milestone for the path towards an evolution and worldwide compliance of the Space Debris Mitigation (SDM) requirements. Small spacecraft classes have limited propulsion capabilities or even they are not provided with propulsion subsystem to achieve a controlled re-entry. This issue brings the need to develop affordable de-orbiting technologies with a limited reliance on the system level performance, ideally largely passive methods. The main aim of this research is to develop passive drag augmentation systems (DAS) for de-orbiting small spacecraft at the end of life, enabling them to comply with SDM requirements. After a feasibility study for the potential commercial use of DAS, the satellites’ need for passive de-orbiting technologies is investigated through market forecast and future scenarios of spacecraft compliance to the 25 years re-entry requirement. Spacecraft subsystems failures are analysed statistically to assess how they might impact the end of mission phase and to guide in the de-orbiting strategy selection. The applicability of current Cranfield DAS design is assessed by developing a simple model for preliminary drag area calculation, validating it with STELA and DRAMA, and calculating the additional area needed vs the area provided by DAS for a spacecraft sample. The requirements for DAS are analysed considering the customer’s needs with respect to the internal design drivers. A design parameters analysis is performed to evaluate the scalability of the DAS and their compatibility with satellite platforms. The parametric study together with the requirements analysis provide useful input to explore new concepts based on the heritage designs. In parallel, the De-Orbit Mechanism (DOM) technological demonstrator is developed from prototype model up to flight model, after undergoing qualification test campaign. The DOM will fly on board the upcoming ESA ESEO mission. This research will enable a commercial DAS products offering that will be an attractive solution for small satellite integrators, allowing them to meet debris mitigation requirements.
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    Modular, reconfigurable approach for a commercial space spacecraft programme
    (Cranfield University, 2003-06) Kingston, Jenny; Bowling, Tom
    This thesis presents the work performed in producing a system-level design for a modular, multipurpose small satellite platform. A multipurpose platform may be applied to a wide range of missions, and, to be commercially viable, the envelope of missions for which it is suitable should be as large as possible. The research therefore addresses the particular requirements that are specific to different mission types, and produces characteristic requirement sets for each. General design requirements are also derived, such as those for enabling modularity and allowing compatibility with different launch vehicles. The commercial requirements arising from the different market and customer sectors are also examined. Industry analysis allows identification of general market trends, and predictions are made regarding the likely size and characteristics of the market in which the proposed platform would compete. It is anticipated there could be a worldwide demand for more than twenty small satellites each year, for which a flexible small spacecraft platform could potentially compete. After derivation of the necessary requirements has been performed, a system-level design of the spacecraft platform is undertaken. The resulting design is based on a multi-module, reconfigurable concept, which can be adapted to fit the different launch envelopes of Pegasus-XL, Taurus, ASAP-5 and larger launchers, and also to accommodate a wide range of payloads. The subsystems are offered in different capability variants, which may be interchanged in response to different mission requirements. The platform equipment and structure forms a "standard parts lisf', from which the appropriate configuration can be built up. Schedule reductions are obtained due to the modular design allowing more of the integration and testing of the platform to be performed in parallel. The proposed programme for development of the platform uses up-front investment to conduct much of the detailed design of the platform in advance of any actual project. This allows the design effort to be shared across many subsequent projects, and the design phase of each new project to be minimised. The key benefits of the proposed platform and programme are adaptability, ability to rapidly reconfigure to mission requirements, suitability for future upgrading, and reduction of the project schedule.
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    What might sustainability of the GEO region look like?
    (Society of Photo-Optical Instrumentation Engineers (SPIE), 2021-10-12) Kingston, Jenny; Felicetti, Leonard; Hobbs, Stephen
    Sustainability in space is often discussed, but as a community we are only gradually learning what it actually means. To inform this understanding, a set of three parallel projects ran at Cranfield University (Oct 2020 to Mar 2021) to develop a scenario of sustainable use of the geostationary orbit region. The three projects were to develop mission designs for (a) a Scavenger spacecraft equipped with tools, actuators and sensors to perform rendezvous with selected satellites at their end of life, to harvest selected parts and components (i.e. solar panels, radiators, antenna reflectors), store and deliver them to the Recycler for refurbishment or recycling, (b) a Recycler space station located in GEO, capable of receiving parts and materials obtained by the Scavenger spacecraft and performing a range of inspection, recycling and repurposing operations on them, and (c) a candidate customer mission: a huge communications satellite based on the Airbus VASANT (VASt ANTenna) concept, with two antenna arrays, each 35 m square, sized to be able to communicate directly from GEO to mobile phone users at Earth's surface. Some of the features highlighted by these studies are (a) the technical challenges of reusing parts from old satellites: modularity and design-for-reuse seem to be key enablers, (b) the advanced robotics and autonomy implied by the on-orbit operations, (c) the challenge of long-term orbit control without excessive propellant consumption, and (d) although the technology is challenging, there are major non-technical challenges for the business case and for aspects such as the legal use of debris, liability for accidents, and compliance with any regulations. Sustainability is challenging, but nature leaves us no alternative.