In-Flight Reconfiguration with System-On-Module Based Architectures for Science Instruments on Nanosatellites

For science payloads on nanosatellite missions, there is a great interest in cost-effective, reliable and state-of-the-art computing performance. Highly integrated system architectures combine reconfigurable System-on-Chip (SoC) devices, memory and peripheral interfaces in a single System-on-Module (SoM) and offer low resource requirements regarding power and mass, but moderate to high processing power capabilities. The major advantages of these architectures are flexibility, (re)programmability, modularity and module reuse. However, it is a challenge to use SoM with COTS based memories devices in a radiation sensitive environment. In order to achieve these requirements, mitigation measures, such as the use of redundant or alternative memory devices and in-flight reconfiguration, are important in terms of reliability. Reprogramming strategies e.g. partial dynamic reconfiguration and scrubbing techniques are published in the past. With a remote sensing instrument for atmospheric temperature measurements using a SRAM-based Xilinx Zynq-7000 SoM, we combine some of these techniques with supervisor circuits to select the boot image from alternative memory devices. The approach distinguishes between programmable logic and processing system reconfiguration, and enables in-flight firmware updates in the case of Single Event Effect (SEE) hazards or changing measurement conditions

Reconciliation of essential process parameters for an enhanced predictability of Arctic stratospheric ozone loss and its climate interactions

Significant reductions in stratospheric ozone occur inside the polar vortices each spring when chlorine radicals produced by heterogeneous reactions on cold particle surfaces in winter destroy ozone mainly in two catalytic cycles, the ClO dimer cycle and the ClO/BrO cycle. Chlorofluorocarbons (CFCs), which are responsible for most of the chlorine currently present in the stratosphere, have been banned by the Montreal Protocol and its amendments, and the ozone layer is predicted to recover to 1980 levels within the next few decades. During the same period, however, climate change is expected to alter the temperature, circulation patterns and chemical composition in the stratosphere, and possible geo-engineering ventures to mitigate climate change may lead to additional changes. To realistically predict the response of the ozone layer to such influences requires the correct representation of all relevant processes. The European project RECONCILE has comprehensively addressed remaining questions in the context of polar ozone depletion, with the objective to quantify the rates of some of the most relevant, yet still uncertain physical and chemical processes. To this end RECONCILE used a broad approach of laboratory experiments, two field missions in the Arctic winter 2009/10 employing the high altitude research aircraft M55-Geophysica and an extensive match ozone sonde campaign, as well as microphysical and chemical transport modelling and data assimilation. Some of the main outcomes of RECONCILE are as follows: (1) vortex meteorology: the 2009/10 Arctic winter was unusually cold at stratospheric levels during the six-week period from mid-December 2009 until the end of January 2010, with reduced transport and mixing across the polar vortex edge; polar vortex stability and how it is influenced by dynamic processes in the troposphere has led to unprecedented, synoptic-scale stratospheric regions with temperatures below the frost point; in these regions stratospheric ice clouds have been observed, extending over >106km2 during more than 3 weeks. (2) Particle microphysics: heterogeneous nucleation of nitric acid trihydrate (NAT) particles in the absence of ice has been unambiguously demonstrated; conversely, the synoptic scale ice clouds also appear to nucleate heterogeneously; a variety of possible heterogeneous nuclei has been characterised by chemical analysis of the non-volatile fraction of the background aerosol; substantial formation of solid particles and denitrification via their sedimentation has been observed and model parameterizations have been improved. (3) Chemistry: strong evidence has been found for significant chlorine activation not only on polar stratospheric clouds (PSCs) but also on cold binary aerosol; laboratory experiments and field data on the ClOOCl photolysis rate and other kinetic parameters have been shown to be consistent with an adequate degree of certainty; no evidence has been found that would support the existence of yet unknown chemical mechanisms making a significant contribution to polar ozone loss. (4) Global modelling: results from process studies have been implemented in a prognostic chemistry climate model (CCM); simulations with improved parameterisations of processes relevant for polar ozone depletion are evaluated against satellite data and other long term records using data assimilation and detrended fluctuation analysis. Finally, measurements and process studies within RECONCILE were also applied to the winter 2010/11, when special meteorological conditions led to the highest chemical ozone loss ever observed in the Arctic. In addition to quantifying the 2010/11 ozone loss and to understand its causes including possible connections to climate change, its impacts were addressed, such as changes in surface ultraviolet (UV) radiation in the densely populated northern mid-latitudes

Reconciliation of essential process parameters for an enhanced predictability of Arctic stratospheric ozone loss and its climate interactions : (RECONCILE) ; activities and results

The international research project RECONCILE has addressed central questions regarding polar ozone depletion, with the objective to quantify some of the most relevant yet still uncertain physical and chemical processes and thereby improve prognostic modelling capabilities to realistically predict the response of the ozone layer to climate change. This overview paper outlines the scope and the general approach of RECONCILE, and it provides a summary of observations and modelling in 2010 and 2011 that have generated an in many respects unprecedented dataset to study processes in the Arctic winter stratosphere. Principally, it summarises important outcomes of RECONCILE including (i) better constraints and enhanced consistency on the set of parameters governing catalytic ozone destruction cycles, (ii) a better understanding of the role of cold binary aerosols in heterogeneous chlorine activation, (iii) an improved scheme of polar stratospheric cloud (PSC) processes that includes heterogeneous nucleation of nitric acid trihydrate (NAT) and ice on non-volatile background aerosol leading to better model parameterisations with respect to denitrification, and (iv) long transient simulations with a chemistry-climate model (CCM) updated based on the results of RECONCILE that better reproduce past ozone trends in Antarctica and are deemed to produce more reliable predictions of future ozone trends. The process studies and the global simulations conducted in RECONCILE show that in the Arctic, ozone depletion uncertainties in the chemical and microphysical processes are now clearly smaller than the sensitivity to dynamic variability

GRIPS-HI, a novel spectral imager for ground based measurements of mesopause temperatures

The NDMC (Network for the Detection of Mesospheric Change) is a global network of measurement sites dedicated to the surveillance of the mesopause region. One main objective of the network is the early identification of climate signals. A key parameter is the mesopause temperature which can be derived from the emission spectrum of a layer of vibrationally excited hydroxyl (OH) at an altitude of approximately 87km. Foremost, emission lines in the SWIR regime between 1520nm and 1550nm are of interest for remote temperature sensing. This report deals with the development of a new generation of GRIPS instruments, which are commonly employed for the observation of mesopause temperatures. The new prototype demonstrates how the application of so called Spatial Heterodyne Interferometers (SHI) can overcome the limitations of currently used grating spectrometers, in terms of spectral resolution and optical throughput. The presented prototype proposes improvements in optical throughput and spectral resolution of about one order of magnitude, significantly reducing the uncertainties of the measured mesopause temperatures. Furthermore, an SHI can be built in monolithic configurations which are aligned and characterized once during assembly without the need of realignment at the measurement site. This makes SHI based instruments ideal for mobile applications

A Long-Life Science Sensor Electronics for Atmospheric Remote Sensing Imaging from CubeSats in Low-Earth-Orbits

CubeSats have become very popular in the past decades which yields to a continuously increasing number of developers in the academic field. For all science missions, customized payload electronics have to be developed, depending on measurement tasks and requirements. Especially for the deployment of more complex remote sensing payloads, state-of-the-art performance is needed to provide operational control and specific data processing of the image sensors. With a highly integrated System on Module (SoM) architecture low resource requirements for both, power and mass, but moderate to high processing power capabilities are available. The major advantages are flexibility, (re)programmability, modularity and module re-use in respect to lower development time and costs. However, it is a challenge to make this module suitable to implement it into space environment. With an efficient approach a radiation tolerant characteristics will be achieved by modelling the radiation environment, estimating the hazards at module level and reducing it to acceptable risks with necessary measures of mitigation techniques. This approach results into a sensor electronics which combines hardware and software redundancies to assure system availability and reliability for long life science missions in Low-Earth-Orbits (LEO). An dual imager electronics design is presented which uses module architecture based on reconfigurable hardware with a processing unit as high integrated commercial-off-the-shelf (COTS) components integrated in a 6U 3U CubeSat. First qualification and acceptance tests with the electronics will be shown

AtmoCube A1: airglow measurements in the mesosphere and lower thermosphere by spatial heterodyne interferometry

The Institute for Atmospheric and Environmental Research at the University of Wuppertal and the Institute of Energy and Climate Research Stratosphere at Research Center Juelich developed a CubeSat payload for atmospheric research. The payload consists of a small interferometer for the observation of airglow near 762 nm. The line intensities of the oxygen A-band are used to derive temperatures in the mesosphere and lower thermosphere region. The temperature data will be used to analyze dynamical wave structures in the atmosphere. The interferometer technology chosen to measure the ro-vibrational structure of the O2 atmospheric band near 762 nm is a spatial heterodyne interferometer originally proposed by Connes in 1958. It can be designed to deliver extraordinary spectral resolution to resolve individual emission lines. The utilization of a two-dimensional imaging detector allows for recording interferograms at adjacent locations simultaneously. Integrated in a six-unit CubeSat, the instrument is designed for limb sounding of the atmosphere. The agility of a CubeSat will be used to sweep the line-of-sight through specific regions of interest to derive a three-dimensional image of an atmospheric volume using tomographic reconstruction technique

A Small Satellite Payload for Airglow Measurements in the Upper Atmosphere by Spatial Heterodyne Interferometry

A novel small satellite payload for atmospheric research has been developed to study the temperature distribution in the mesosphere and lower thermosphere region. The payload consists of a small interferometer for the observation of airglow at 762 nm. The line intensities of the O2 A-band emissions are used to derive temperatures in the upper atmosphere. The temperature data will be used to analyze dynamical wave structures in the atmosphere which are important for modeling of the climate system. Integrated in a small satellite or a 6U CubeSat, the instrument needs a highly accurate attitude determination and control systems in the sub-arcmin range for limb sounding of the atmosphere. The payload electronics concept is based on a System-on-Module architecture which combines reconfigurable hardware with a processing unit as a highly integrated component. The agility of a CubeSat or the maneuverability of a small satellite can be used to focus the measurements on specific regions in the atmosphere from different viewing directions. Three-dimensional images of an atmospheric volume can be derived using tomographic reconstruction techniques. A prototype of this payload, launched on a Chinese technology demonstration satellite in December 2018, proved the practical usability of this instrument design

A Highly Miniaturized Satellite Payload Based on a Spatial Heterodyne Spectrometer for the Detection of Faint Emissions in the Atmosphere

A highly miniaturized limb sounder for the observation of faint emissions in the atmosphere is presented. The selected technology is a Spatial Heterodyne Spectrometer (SHS). The throughput of a SHS is orders of magnitude larger than of a conventional grating spectrometer of the same size. Its monolithic design makes it extremely robust against vibrations and shocks. It can be designed to deliver spectra at very high spectral resolution to resolve individual emission or absorption lines, or even Doppler shifts to derive winds. The small mass and low energy consumption makes SHS instruments particularly suitable for the deployment on nano-satellites or as secondary payloads on satellite constellations. In this presentation we introduce an instrument for the measurement of temperature in the mesosphere and lower thermosphere by observing the ro- vibrational structure of the O2 atmospheric band at 762 nm in limb viewing geometry is presented. This instrument is suited to fly on a 3-6 unit CubeSat or as a secondary payload on a larger satellite