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Design space exploration (DSE) is a key activity in embedded system design methodologies and can be supported by well-defined models of computation (MoCs) and predictable platform architectures. The original design model, covering the application models, platform models and design constraints needs to be converted into a form analyzable by computer-aided decision procedures such as mathematical programming or genetic algorithms. This conversion is the process of design space identification (DSI), which becomes very challenging if the design domain comprises several MoCs and platforms. For a systematic solution to this problem, separation of concerns between the design domain and decision domain is of key importance. We propose in this paper a systematic DSI scheme that is (a) composable, as it enables the stepwise and simultaneous extension of both design and decision domain, and (b) tuneable, because it also enables different DSE solving techniques given the same design model. We exemplify this DSI scheme by an illustrative example that demonstrates the mechanisms for composition and tuning. Additionally, we show how different compositions can lead to the same decision model as an important property of this DSI scheme. Part of proceedings ISBN: 978-3-9819263-5-4QC 20220413

Frequency stabilized light sources with narrow linewidth are mandatory for atom interferometry based experiments. For compact experiment designs used on space platforms, tunable DFB diode lasers are often used. These lasers combine low energy consumption with small sizes, but lack long-term frequency stability. This paper presents an FPGA based laser frequency stabilization system for highly variable target frequencies using frequency modulated Rb-spectroscopy achieving latencies below 100 μs. The system consists of a DFB laser, a Rb-spectroscopy cell, a laser current controller and an FPGA board with an analog-digital conversion board. The digital part of the frequency stabilization system is a SoC mapped on an FPGA. The SoC consists of a processor, enabling user interaction via network connection, and the dedicated frequency stabilization module. This module consists of a demodulation stage, digital filters, a frequency estimator and a controller. To estimate the frequency, small ramps of the laser frequency are generated using a high-speed DAC connected to the laser current controller. The absorption spectroscopy output of this beam is sampled using a photodiode and a high-speed ADC. After signal conditioning with digital filters, the frequency estimator extracts the present mid-frequency of the laser applying pattern matching with a prerecorded reference spectrum. The frequency controller adjusts the mean laser current based on this estimation. The performance as well as the accuracy of the proposed laser stabilization system and its FPGA resource and power consumption are evaluated.

The impact of NO2 and other atmospheric trace gases on health and the environment is now acknowledged by governments around the world. The sources, both natural and anthropogenic, have been shown to affect the quality of life due to low air quality in densely populated areas. Consequently, the need for accurate global NO2 measurements with high spatial- A nd temporal resolution to monitor NO2 is becoming ever more important. Through an ESA study, TNO and KNMI have been evaluating measurement requirements and an instrument design for a Compact NO2 Spectrometer', based on a hyperspectral imaging instrument operating in the VIS (405-490nm] spectral range and aimed at combining the performance of state-of-the-art instruments with fine spatial sampling (0.5x0.5 km2). By use of a novel free-form optics a very compact low volume and low mass design has been achieved. Combining this with other small satellite design approaches for components the aim is to create a low cost instrument capable of being flown on a wide variety of space platforms. Global daily coverage can then be achieved with a relatively small constellation of instruments. The key design features are described for a 'Compact NO2 Spectrometer', such as the optical design approach, the use of free-form optics, an thermal' all aluminium approach. An overview of the development and airborne results from a breadboard of a small prototype system (Spectrolite) developed by TNO which uses many of the design features envisaged for this new instrument is given.

The impact of NO2 and other atmospheric trace gases on health and the environment is now acknowledged by governments around the world. The sources, both natural and anthropogenic, have been shown to affect the quality of life due to low air quality in densely populated areas. Consequently, the need for accurate global NO2 measurements with high spatial- A nd temporal resolution to monitor NO2 is becoming ever more important. Through an ESA study, TNO and KNMI have been evaluating measurement requirements and an instrument design for a Compact NO2 Spectrometer', based on a hyperspectral imaging instrument operating in the VIS (405-490nm] spectral range and aimed at combining the performance of state-of-the-art instruments with fine spatial sampling (0.5x0.5 km2). By use of a novel free-form optics a very compact low volume and low mass design has been achieved. Combining this with other small satellite design approaches for components the aim is to create a low cost instrument capable of being flown on a wide variety of space platforms. Global daily coverage can then be achieved with a relatively small constellation of instruments. The key design features are described for a 'Compact NO2 Spectrometer', such as the optical design approach, the use of free-form optics, an thermal' all aluminium approach. An overview of the development and airborne results from a breadboard of a small prototype system (Spectrolite) developed by TNO which uses many of the design features envisaged for this new instrument is given.

The GAMMA-400 gamma-ray telescope is intended to measure the fluxes of gamma-rays and cosmic-ray electrons and positrons in the energy range from 100 MeV to several TeV. Such measurements concern the following scientific tasks: investigation of point sources of gamma-rays, studies of the energy spectra of Galactic and extragalactic diffuse emission, studies of gamma-ray bursts and gamma-ray emission from the Sun, as well as high precision measurements of spectra of high-energy electrons and positrons. Also the GAMMA- 400 instrument provides the possibility for protons and nuclei measurements up to knee. But the main goal for the GAMMA-400 mission is to perform a sensitive search for signatures of dark matter particles in high-energy gamma-ray emission. To fulfill these measurements the GAMMA-400 gamma-ray telescope possesses unique physical characteristics in comparison with previous and present experiments. The major advantage of the GAMMA-400 instrument is excellent angular and energy resolution for gamma-rays above 10 GeV. The GAMMA-400 experiment will be installed onboard of the Navigator space platform, manufactured by the NPO Lavochkin Association. The expected orbit will be a highly elliptical orbit (with apogee 300.000 km and perigee 500 km) with 7 days orbital period. An important profit of such an orbit is the fact that the full sky coverage will always be available for gamma ray astronomy.

This paper is devoted to the feasibility study of a wireless sensing system, mainly based on passive surface acoustic wave sensors, for remote measurement of temperature aboard space platforms. The use of passive sensors is particularly attractive since they need no battery and are robust in extreme environments, as they contain no active electronic circuits. The main objective of this paper is the complete characterization of the wireless system environment, in order to determine the main fundamental limits of this technology from a communication theory point of view. Preliminary experimental measurements are used for defining the main environment parameters, validating some of the theoretical limit computations, and proving the space application feasibility.

The Miura Ori is a mechanism composed by a polyhedral deployable surface. It has favorable qualities from engineering prospective that lead the growing interest on it. The present work focuses on its transmission of motion. The mechanism can be represented by spherical 4 bar linkages, and on this account a simple and effective mobility formula is presented. The mechanism having a number of excessive rigid members, it is also possible to remove all or some of them, variously arranged. The changes are included in the calculation of allowable mobility of the system. The resulting tool can be directly used for the design of deployable Miura Ori surfaces with customized shape.

The GAMMA-400 gamma-ray telescope currently under development is designed to measure fluxes of gamma rays and electron-positron cosmic-ray components, which could be associated with the annihilation or decay of dark matter particles, and to survey in detail the celestial sphere in order to search for and investigate discrete gamma-ray sources; to measure the energy spectra of Galactic and extragalactic dif- fuse gamma-ray emissions; and to study gamma-ray bursts and the gamma-ray emissions of active Sun. The GAMMA-400 energy range is 100 MeV to 3000 GeV. The gamma-ray telescope has an angular resolution of ∼0.01°, an energy resolution of ∼1%, and a proton rejection factor of ∼106. The GAMMA-400 will be installed on Russia’s Navigator space platform. Observations are planned to commence in 2018.

Space structures are common in covering large area with few or no intermittent supports. The catastrophic failures of space structures are frequently reported and it urges to develop suitable techniques to prevent such failures. The composite space structures are found to be an efficient solution, in which the forces in the critical compression members are redistributed and safe guarded with concrete slabs. In this study, numerical studies were conducted using a standard finite element analysis package. Effect of shear connectors with varying heights on the behaviour of the space structure is studied. Results are compared with the steel space structure and composite space structure with full shear interaction. The maximum deflection observed in the steel space structure for the service load is less than span/300 and the maximum deflection observed in the steel concrete composite space structure for the service load is less than span/360, which ensures the serviceability conditions. The results show about 20 to 30 percent of reduction in deflection with about 250 percent increase in stiffness due to the composite action for the service load. The results substantiate that the length of shear connector should be equal to the concrete depth for more efficient composite interaction. The composite action is more effective and efficient in composite space structure for larger spans compared to shorter spans.

Double layered grid space structures are well known in the building industry for their ability to cover large areas. This paper presents the results of a parametric study on the various factors affecting the flexural behavior of double layered grid space structures, considering (i) various support arrangement (ii) concrete slab at the top and (iii) an experimental investigation on a full scale space grid. Based on the study it was concluded that top concrete slab enhances not only the strength of top chord compression members but also increase the strength and stiffness of the system with a fail safe system. It was found from the study that atleast 20% saving in steel is possible with a mid edge supported system.

High altitude Platforms represent a very attractive solution to enhance space communications in terms of available capacity and system topology. They can be geared with multi-functional payload, both for communications and Earth Observation missions. Thanks to their opportune position, they are the key for optics and RF technology integration in space communications. In this paper we evaluate the feasibility of an optical HAP-GEO-HAP link over more than 80,000 km above the stratosphere. In particular, we consider a system based on 1550 nm technology, that exploits the potentialities of DPSK modulation format with Direct-Detection balanced interferometer receiver, and optical amplifier.

The wide bandwidth offered by optical communications systems, is attracting more and more interest in space applications. Investigation has been carried out either on suitable modulations or resilient architectures for communications and Earth Observation (EO) missions. New elements have been introduced: High-Altitude- Platforms (HAP's), whose characteristics allow us to carry out an optical link between unmoving terminals, if GEO satellites are involved. This paper is describing an architecture for EO, based on two HAP's linked via a GEO satellite, whose optical payload offers an inline-like amplification for an overall link that can extend over 80,000 km. The aim of our work is to present a low power consumption system that guarantees the required Bit Error Rate (BER) . Both Direct Detection (DD) and coherent (homodyne and heterodyne) systems will be considered.

SEE ParentDocumentRecord|Ntt=19940004512 "USRA, NASA(USRA University Advanced Design Program Fifth Annual Summer Conference"; p. p 111-121 The Naval Postgraduate School's (NPS) Space Systems Academic Group (SSAG) is designing and developing a small communications satellite for launch aboard the shuttle as a complex autonomous payload (CAP). The objectives of PANSAT are three-fold. First, PANSAT will provide an ideal educational tool for the officer students at NPS supporting Space Systems Engineering and Space Systems Operations with hands-on hardware development. Second, the satellite will provide digital store-and-forward communications, or packet radio, for the amateur radio community. The third objective is to provide a low-cost, space-based platform for small experiments. PANSAT will be launched from the shuttle at a nominal altitude of 200 n.m. and an inclination of at least 37 degrees. The satellite weight is 150 lbs. Since there is no attitude control, eight dipole whip antennas will be used to provide isotropic ground coverage for communications. FM digital communications will be used with up-link and down-link on a single frequency in the amateur band of 437.25 MHz. A maximum 50 kHz of bandwidth is envisioned for the satellite. The expected lifetime of the satellite is 1 1/2 to 2 years before atmospheric reentry. The PANSAT design consists of the following: communications subsystem (COMM); computer, or data processor and sequencer (DP&S); power subsystem; structure subsystem; and experiment payload. Approved for public release; distribution is unlimited.