BEAVIS: Balloon Enabled Aerial Vehicle for IoT and Sensing

UAVs are becoming versatile and valuable platforms for various applications. However, the main limitation is their flying time. We present BEAVIS, a novel aerial robotic platform striking an unparalleled trade-off between the maneuverability of drones and the long-lasting capacity of blimps. BEAVIS scores highly in applications where drones enjoy unconstrained mobility yet suffer from limited lifetime. A nonlinear flight controller exploiting novel, unexplored, aerodynamic phenomena to regulate the ambient pressure and enable all translational and yaw degrees of freedom is proposed without direct actuation in the vertical direction. BEAVIS has built-in rotor fault detection and tolerance. We explain the design and the necessary background in detail. We verify the dynamics of BEAVIS and demonstrate its distinct advantages, such as agility, over existing platforms including the degrees of freedom akin to a drone with 11.36× increased lifetime. We exemplify the potential of BEAVIS to become an invaluable platform for many applications

Pleiades High Resolution Satellite : A Solution for Military and Civilian Needs in Metric-Class Optical Observation

In 2000, Cnes (French space agency) decided to initiate the Pleiades program consisting in a constellation of European satellite components dedicated to Earth observation. Astrium is in charge of the first French component, named Pleiades High Resolution, as satellite prime contractor. This satellite aims at fulfilling the needs of French and Italian governments, for both civilian and military users, in metric-class optical observation at the 2006 horizon. This small satellite weighting around 900 kg will orbit at 695 km on a Sun synchronous orbit. It will provide colored images of more than 20 km swath, with a panchromatic resolution better than 1 meter, and a multi-spectral resolution of 2.8 m at nadir. The image data handling chain will make maximum use of the onboard 600 Gbits solid state mass memory, and of the downlink at 600 Mbps in X-band. The satellite will provide high image quality performances, characterized by a highly stable dynamic behavior, and an autonomous image location better than 20 m (maximum). This highly agile spacecraft will maneuver 60 deg in less than 25 sec. To support those performances, new technologies will be used, such as light material with high thermal stability for the instrument structure, integrated detection electronics near the focal plane, Control Moment Gyros for agility, Fiber Optic Gyros for high accuracy attitude measurement, Li-ion batteries and triple junction solar cells for a power system maximum efficiency. After a short mission introduction, the paper presents the satellite design with its different functional chains. The satellite performances are then presented

IXPE Mission System Concept and Development Status

The Goal of the Imaging X-Ray Polarimetry Explorer (IXPE) Mi SMEX), is to expand understanding of high-energy astrophysical processes and sources, in support of NASAs first science objective in Astrophysics: Discover how the universe works. IXPE, an international collaboration, will conduct X-ray imaging polarimetry for multiple categories of cosmic X-ray sources such as neutron stars, stellar-mass black holes, supernova remnants and active galactic nuclei. The Observatory uses a single science operational mode capturing the X-ray data from the targets. The IXPE Observatory consists of spacecraft and payload modules built up in parallel to form the Observatory during system integration and test. The payload includes three X-ray telescopes each consisting of a polarization-sensitive, gas pixel X-ray detector, paired with its corresponding grazing incidence mirror module assembly (MMA). A deployable boom provides the correct separation (focal length) between the detector units (DU) and MMAs. These payload elements are supported by the IXPE spacecraft which is derived from the BCP-small spacecraft architecture. This paper summarizes the IXPE mission science objectives, updates the Observatory implementation concept including the payload and spacecraft ts and summarizes the mission status since last years conference

The Large UV/Optical/Infrared Surveyor (LUVOIR): Decadal Mission Concept Design Update

In preparation for the 2020 Astrophysics Decadal Survey, NASA has commissioned the study of four large mission concepts, including the Large Ultraviolet / Optical / Infrared (LUVOIR) Surveyor. The LUVOIR Science and Technology Definition Team (STDT) has identified a broad range of science objectives including the direct imaging and spectral characterization of habitable exoplanets around sun-like stars, the study of galaxy formation and evolution, the epoch of reionization, star and planet formation, and the remote sensing of Solar System bodies. NASAs Goddard Space Flight Center (GSFC) is providing the design and engineering support to develop executable and feasible mission concepts that are capable of the identified science objectives. We present an update on the first of two architectures being studied: a 15-meter-diameter segmented-aperture telescope with a suite of serviceable instruments operating over a range of wavelengths between 100 nm to 2.5 microns. Four instruments are being developed for this architecture: an optical / near-infrared coronagraph capable of 10(exp -10) contrast at inner working angles as small as 2 lambda/D; the LUVOIR UV Multi-object Spectrograph (LUMOS), which will provide low- and medium-resolution UV (100 400 nm) multi-object imaging spectroscopy in addition to far-UV imaging; the High Definition Imager (HDI), a high-resolution wide-field-of-view NUV-Optical-IR imager; and a UV spectro-polarimeter being contributed by Centre National dEtudes Spatiales (CNES). A fifth instrument, a multi-resolution optical-NIR spectrograph, is planned as part of a second architecture to be studied in late 2017

Practical Results on the Development of a Control Moment Gyro Based Attitude Control System for Agile Small Satellites

In this paper a new practical Attitude Control System is proposed, based on Control Moment Gyroscopes (CMG). These actuators can provide unique torque, angular momentum and slew rate capabilities to small satellites without any increase in power, mass or volume. This will help small satellites become more agile and maneuverable. Agility considerably increases the operational envelope and efficiency of spacecraft and substantially increases the return of earth and science mission data. The paper focuses on the practical work on developing the hardware for a low cost, miniature CMG for agile small satellites. Experimental results indicate the potential benefits of using CMGs. Specifically, a cluster of four Single Gimbal CMGs (SGCMG) is used to practically demonstrate full 3-axis control for a microsatellite class spacecraft. Additionally, results are presented on the development of a larger SGCMG proposed as an experimental payload for future enhanced microsatellite missions

Operationally Responsive Space: Past, Present and Future

Where did the idea of Operationally Responsive Space originate? You might imagine that the idea was born during the First Gulf War, (sometimes called the First Space War), where use was made of strategic space systems to support operations. It was apparent, though, that strategic systems with very small fields of view and long revisit times were not well suited to operational reconnaissance. Other limitations of these strategic systems included a tasking system not suited for tactical timelines; significant data downlink requirements, making it difficult to deliver data into the theatre; a large in-theatre “footprint” for intelligence analysts; and lack of “command assurance” that the requested collection would not be pre-empted by higher national priorities, for which reason field commanders were unwilling to place reliance on them for critical operations. It is tempting to think that these limitations inspired system designers to conceive of constellations of smaller, more affordable satellites with wider fields of view

Imaging X-Ray Polarimetry Explorer Mission Attitude Determination and Control Concept

The goal of the Imaging X-Ray Polarimetry Explorer (IXPE) Mission is to expand understanding of high-energy astrophysical processes and sources, in support of NASA's first science objective in Astrophysics: "Discover how the universe works." X-ray polarimetry is the focus of the IXPE science mission. Polarimetry uniquely probes physical anisotropies-ordered magnetic fields, aspheric matter distributions, or general relativistic coupling to black-hole spin-that are not otherwise measurable. The IXPE Observatory consists of Spacecraft and Payload modules. The Payload includes three polarization sensitive, X-ray detector units (DU), each paired with its corresponding grazing incidence mirror module assemblies (MMA). A deployable boom provides the correct separation (focal length) between the DUs and MMAs. These Payload elements are supported by the IXPE Spacecraft. A star tracker is mounted directly with the deployed Payload to minimize alignment errors between the star tracker line of sight (LoS) and Payload LoS. Stringent pointing requirements coupled with a flexible structure and a non-collocated attitude sensor-actuator configuration requires a thorough analysis of control-structure interactions. A non-minimum phase notch filter supports robust control loop stability margins. This paper summarizes the IXPE mission science objectives and Observatory concepts, and then it describes IXPE attitude determination and control implementation. IXPE LoS pointing accuracy, control loop stability, and angular momentum management are discussed

System modelling of very low Earth orbit satellites for Earth observation

The operation of satellites in very low Earth orbit (VLEO) has been linked to a variety of benefits to both the spacecraft platform and mission design. Critically, for Earth observation (EO) missions a reduction in altitude can enable smaller and less powerful payloads to achieve the same performance as larger instruments or sensors at higher altitude, with significant benefits to the spacecraft design. As a result, renewed interest in the exploitation of these orbits has spurred the development of new technologies that have the potential to enable sustainable operations in this lower altitude range. In this paper, system models are developed for (i) novel materials that improve aerodynamic performance enabling reduced drag or increased lift production and resistance to atomic oxygen erosion and (ii) atmosphere-breathing electric propulsion (ABEP) for sustained drag compensation or mitigation in VLEO. Attitude and orbit control methods that can take advantage of the aerodynamic forces and torques in VLEO are also discussed. These system models are integrated into a framework for concept-level satellite design and this approach is used to explore the system-level trade-offs for future EO spacecraft enabled by these new technologies. A case-study presented for an optical very-high resolution spacecraft demonstrates the significant potential of reducing orbital altitude using these technologies and indicates possible savings of up to 75% in system mass and over 50% in development and manufacturing costs in comparison to current state-of-the-art missions. For a synthetic aperture radar (SAR) satellite, the reduction in mass and cost with altitude were shown to be smaller, though it was noted that currently available cost models do not capture recent commercial advancements in this segment. These results account for the additional propulsive and power requirements needed to sustain operations in VLEO and indicate that future EO missions could benefit significantly by operating in this altitude range. Furthermore, it is shown that only modest advancements in technologies already under development may begin to enable exploitation of this lower altitude range. In addition to the upstream benefits of reduced capital expense and a faster return on investment, lower costs and increased access to high quality observational data may also be passed to the downstream EO industry, with impact across a wide range of commercial, societal, and environmental application areas

First In-Orbit Results from the UoSAT -12 Minisatellite

In 1995, having built and launched twelve 50-kg micro satellites, the Surrey Space Centre made a strategic decision to develop and demonstrate a larger low-cost satellite platform. This internally-funded project became the UoSAT-12 research and development minisatellite, a 325-kg satellite demonstrating key bus and payload technologies. On 21 April, a converted SS-18 Inter Continental Ballistic Missile (ICBM) placed Surrey\u27s UoSAT-12 minisatellite in a 650 km, 65° orbit. The in-orbit acquisition and check-out of the satellite have been successful. Engineers operating the satellite from Surrey\u27s mission control centre have received initial results from attitude control, remote sensing, Global Positioning System (GPS) orbit determination, L-to-S band communications and orbit station-keeping systems

On Small Satellites for Oceanography: A Survey

The recent explosive growth of small satellite operations driven primarily from an academic or pedagogical need, has demonstrated the viability of commercial-off-the-shelf technologies in space. They have also leveraged and shown the need for development of compatible sensors primarily aimed for Earth observation tasks including monitoring terrestrial domains, communications and engineering tests. However, one domain that these platforms have not yet made substantial inroads into, is in the ocean sciences. Remote sensing has long been within the repertoire of tools for oceanographers to study dynamic large scale physical phenomena, such as gyres and fronts, bio-geochemical process transport, primary productivity and process studies in the coastal ocean. We argue that the time has come for micro and nano satellites (with mass smaller than 100 kg and 2 to 3 year development times) designed, built, tested and flown by academic departments, for coordinated observations with robotic assets in situ. We do so primarily by surveying SmallSat missions oriented towards ocean observations in the recent past, and in doing so, we update the current knowledge about what is feasible in the rapidly evolving field of platforms and sensors for this domain. We conclude by proposing a set of candidate ocean observing missions with an emphasis on radar-based observations, with a focus on Synthetic Aperture Radar.Comment: 63 pages, 4 figures, 8 table