scholarly journals Characterization of dark current signal measurements of the ACCDs used on board the Aeolus satellite

2021 ◽  
Vol 14 (7) ◽  
pp. 5153-5177
Author(s):  
Fabian Weiler ◽  
Thomas Kanitz ◽  
Denny Wernham ◽  
Michael Rennie ◽  
Dorit Huber ◽  
...  
Keyword(s):  
Dark Current ◽  
European Space Agency ◽  
Current Signal ◽  
Wind Retrieval ◽  
Root Cause ◽  
Space Agency ◽  
Correction Scheme ◽  
Successful Launch ◽  
Flight Hardware

Abstract. Even just shortly after the successful launch of the European Space Agency satellite Aeolus in August 2018, it turned out that dark current signal anomalies of single pixels (so-called “hot pixels”) on the accumulation charge-coupled devices (ACCDs) of the Aeolus detectors detrimentally impact the quality of the aerosol and wind products, potentially leading to wind errors of up to several meters per second. This paper provides a detailed characterization of the hot pixels that occurred during the first 1.5 years in orbit. The hot pixels are classified according to their characteristics to discuss their impact on wind measurements. Furthermore, mitigation approaches for the wind retrieval are presented and potential root causes for hot pixel occurrence are discussed. The analysis of the dark current signal anomalies reveals a large variety of anomalies ranging from pixels with random telegraph signal (RTS)-like characteristics to pixels with sporadic shifts in the median dark current signal. Moreover, the results indicate that the number of hot pixels almost linearly increased during the observing period between 2 September 2018 and 20 May 2020 with 6 % of the ACCD pixels affected in total at the end of the period leading to 9.5 % at the end of the mission lifetime. This work introduces dedicated instrument calibration modes and ground processors, which allowed for a correction shortly after a hot pixel occurrence. The achieved performance with this approach avoids risky adjustments to the in-flight hardware operation. It is demonstrated that the success of the correction scheme varies depending on the characteristics of each hot pixel itself. With the herein presented categorization, it is shown that multi-level RTS pixels with high fluctuation are the biggest challenge for the hot pixel correction scheme. Despite a detailed analysis in this framework, no conclusion could be drawn about the root cause of the hot pixel issue.

scholarly journals Characterization of dark current signal measurements of the ACCDs used on-board the Aeolus satellite

2020 ◽  
Author(s):  
Fabian Weiler ◽  
Thomas Kanitz ◽  
Denny Wernham ◽  
Michael Rennie ◽  
Dorit Huber ◽  
...  
Keyword(s):  
Dark Current ◽  
European Space Agency ◽  
Current Signal ◽  
Wind Retrieval ◽  
Root Cause ◽  
Space Agency ◽  
Correction Scheme ◽  
Successful Launch ◽  
Wind Measurements

Abstract. Already shortly after the successful launch of the European Space Agency satellite Aeolus in August 2018, it turned out that dark current signal anomalies of single pixels (so-called hot pixels) on the Accumulation-Charge-Coupled Devices (ACCDs) of the Aeolus detectors detrimentally impact the quality of the aerosol and wind products potentially leading to wind errors of up to 4 m/s. This paper provides a detailed characterization of the hot pixels which occurred during the first one and a half years in orbit. The hot pixels are classified according to their characteristics to discuss their impact on wind measurements. Furthermore, mitigation approaches for the wind retrieval are presented and potential root causes for the hot pixel occurrence are discussed. The analysis of the dark current signal anomalies reveals a large variety of anomalies ranging from pixels with Random Telegraph Signal (RTS)-like characteristics to pixels with sporadic shifts in the median dark current signal. Moreover, the results indicate that the number of hot pixels has almost linearly increased during the observing period between 2018-09-02 until 2020-05-20 with 6 % of the ACCD pixels affected in total at the end of the period leading to 9.5 % at the end of mission lifetime. This work introduces dedicated instrument calibration modes and ground processors which allowed for a correction shortly after a hot pixel occurrence. The achieved performance with this approach avoids risky adjustments to the inflight hardware operation. It is demonstrated that the success of the correction scheme varies depending on the characteristics of each hot pixel itself. With the herein presented categorization, it is shown that multi-level RTS pixels with high fluctuation are the biggest challenge for the hot pixel correction scheme. Despite a detailed analysis in this framework, no conclusion could be drawn about the root cause of the hot pixel issue.

scholarly journals Calibrations and Wind Observations of an Airborne Direct-Detection Wind LiDAR Supporting ESA’s Aeolus Mission

2018 ◽  
Vol 10 (12) ◽  
pp. 2056 ◽  
Author(s):  
Uwe Marksteiner ◽  
Christian Lemmerz ◽  
Oliver Lux ◽  
Stephan Rahm ◽  
Andreas Schäfler ◽  
...  
Keyword(s):  
Direct Detection ◽  
European Space Agency ◽  
Measurement Data ◽  
Calibration Method ◽  
Satellite Mission ◽  
Absolute Deviation ◽  
Wind Retrieval ◽  
Space Agency ◽  
Successful Launch ◽  
Wind Lidar

The Aeolus satellite mission of the European Space Agency (ESA) has brought the first wind LiDAR to space to satisfy the long-existing need for global wind profile observations. Until the successful launch on 22 August 2018, pre-launch campaign activities supported the validation of the measurement principle, the instrument calibration, and the optimization of retrieval algorithms. Therefore, an airborne prototype instrument has been developed, the ALADIN Airborne Demonstrator (A2D), with ALADIN being the Atmospheric Laser Doppler Instrument of Aeolus. Two airborne campaigns were conducted over Greenland, Iceland and the Atlantic Ocean in September 2009 and May 2015, employing the A2D as the first worldwide airborne direct-detection Doppler Wind LiDAR (DWL) and a well-established coherent 2-µm wind LiDAR. Both wind LiDAR instruments were operated on the same aircraft measuring Mie backscatter from aerosols and clouds as well as Rayleigh backscatter from molecules in parallel. This paper particularly focuses on the instrument response calibration method of the A2D and its importance for accurate wind retrieval results. We provide a detailed description of the analysis of wind measurement data gathered during the two campaigns, introducing a dedicated aerial interpolation algorithm that takes into account the different resolution grids of the two LiDAR systems. A statistical comparison of line-of-sight (LOS) winds for the campaign in 2015 yielded estimations of the systematic and random (mean absolute deviation) errors of A2D observations of about 0.7 m/s and 2.1 m/s, respectively, for the Rayleigh, and 0.05 m/s and 2.3 m/s, respectively, for the Mie channel. In view of the launch of Aeolus, differences between the A2D and the satellite mission are highlighted along the way, identifying the particular assets and drawbacks.

Combining ExoMars’ Ma_MISS and Drill data

2020 ◽  
Author(s):  
Alessandro Frigeri ◽  
Maria Cristina De Sanctis ◽  
Francesca Altieri ◽  
Simone De Angelis ◽  
Marco Ferrari ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Water Content ◽  
Large Scale ◽  
Mechanical Response ◽  
European Space Agency ◽  
Volcanic Rocks ◽  
Space Agency ◽  
Geophysical Imaging

<p>The ExoMars Rover and Surface Platform planned for launch in 2022 is a large international cooperation between the European Space Agency and Roscosmos with a scientific contribution from NASA.  Thales Alenia Space is the ExoMars mission industrial prime contractor. </p> <p>Besides sensors and instruments characterizing the surface at large scale, the ExoMars’ rover Rosalind Franklin payload features some experiments devoted specifically to the characterization of the first few meters of the Martian subsurface. These experiments are particularly critical for the main ExoMars objective of detecting traces of present or past life forms on Mars, which may have been preserved within the shallow Martian underground [1].</p> <p>Rosalind Franklin will be able to perform both non-invasive geophysical imaging of the underground [2] and subsurface <em>in situ</em> measurements thanks to the Drill unit installed on the rover. The Drill has been developed by Leonardo and its purposes are 1) to collect core samples to be analyzed in the Analytical Laboratory Drawer (ALD) onboard the Rover and 2) to drive the miniaturized spectrometer Ma_MISS within the borehole.   </p> <p>Ma_MISS (Mars Multispectral Imager for Subsurface Studies, [3]) will collect mineralogic measurements from the rocks exposed into the borehole created by the Drill with a spatial resolution of 120 μm down to 2 meters into the Martian subsurface.</p> <p>Rocks are composed of grains of minerals, and their reaction to an applied stress is related to the mechanical behavior of the minerals that compose the rock itself. The mechanical properties of a mineral depend mainly on the strength of the chemical bonds, the orientation of crystals, and the number of impurities in the crystal lattice.</p> <p>In this context, the integration of Ma_MISS measurements and drill telemetry are of great importance.  The mechanical properties of rocks coupled with their mineralogic composition provide a rich source of information to characterize the nature of rocks being explored by ExoMars rover’s drilling activity.</p> <p>Within our study, we are starting to collect telemetry recorded during the Drill unit tests on several samples ranging from sedimentary to volcanic rocks with varying degrees of weathering and water content.  In this first phase of the study, we focused our attention on the variation of torque and penetration speed between different samples, which have been found to be indicative of a particular type of rock or group of rocks and their water content.  </p> <p>We are planning to analyze the same rocks with the Ma_MISS breadboard creating the link between the mineralogy and the mechanical response of the Drill.      </p> <p>This will put the base for a more comprehensive and rich characterization of the <em>in situ</em> subsurface observation by Rosalind Franklin planned at Oxia Planum, Mars in 2023. </p> <p> </p> <p><strong>Acknowledgments: </strong>We thank the European Space Agency (ESA) for developing the ExoMars Project, ROSCOSMOS and Thales Alenia Space for rover development, and Italian Space Agency (ASI) for funding the Ma_MISS experiment (ASI-INAF contract n.2017-48-H.0 for ExoMars MA_MISS phase E/science).</p> <p> </p> <p><strong>References</strong></p> <p>[1] Vago et al., 2017. Astrobiology, 17 6-7. [2] Ciarletti et al., 2017. Astrobiology, 17 6-7. [3] De Sanctis et al., 2017. Astrobiology, 17 6-7.</p>

scholarly journals Uncertainty characterization of AOD for the AATSR dual and single view retrieval algorithms

2013 ◽  
Vol 6 (2) ◽  
pp. 4039-4075 ◽  
Author(s):  
P. Kolmonen ◽  
A.-M. Sundström ◽  
L. Sogacheva ◽  
E. Rodriguez ◽  
T. Virtanen ◽  
...  
Keyword(s):  
Climate Models ◽  
European Space Agency ◽  
Single View ◽  
Space Agency ◽  
Retrieval Algorithms ◽  
Statistical Sense ◽  
Using Data ◽  
Along Track ◽  
Global Uncertainty

Abstract. The uncertainty associated with satellite-retrieved aerosol properties is needed when these data are used to constrain chemical transport or climate models by using data assimilation. Global uncertainty as provided by comparison with independent ground-based observations is usually not adequate for that purpose. Rather the per-pixel uncertainty is needed. In this work we describe how these are determined in the AATSR dual and single view aerosol retrieval algorithms (ADV and ASV) which are used to retrieve aerosol optical properties from reflectance measured at the top of the atmosphere. AATSR is the Aerosol Along-Track Scanning Radiometer which flies on the European Space Agency Environmental Satellite ENVISAT. In addition, issues related to multi-year retrievals are described and discussed. The aerosol optical depth (AOD) retrieved for the year 2008 is validated versus ground-based AERONET sun photometer measurements with good agreement (r = 0.85). The comparison of the AOD uncertainties with those provided by AERONET shows that they behave well in a statistical sense. Other considerations regarding global multi-year aerosol retrievals are presented and discussed.

scholarly journals BepiColombo - Mission Overview and Science Goals

2021 ◽  
Vol 217 (8) ◽  
Author(s):  
J. Benkhoff ◽  
G. Murakami ◽  
W. Baumjohann ◽  
S. Besse ◽  
E. Bunce ◽  
...  
Keyword(s):  
Solar System ◽  
European Space Agency ◽  
Terrestrial Planet ◽  
Origin And Evolution ◽  
Space Agency ◽  
History Of ◽  
Joint Mission ◽  
Scientific Return ◽  
Scientific Payload

AbstractBepiColombo is a joint mission between the European Space Agency, ESA, and the Japanese Aerospace Exploration Agency, JAXA, to perform a comprehensive exploration of Mercury. Launched on $20^{\mathrm{th}}$ 20 th October 2018 from the European spaceport in Kourou, French Guiana, the spacecraft is now en route to Mercury.Two orbiters have been sent to Mercury and will be put into dedicated, polar orbits around the planet to study the planet and its environment. One orbiter, Mio, is provided by JAXA, and one orbiter, MPO, is provided by ESA. The scientific payload of both spacecraft will provide detailed information necessary to understand the origin and evolution of the planet itself and its surrounding environment. Mercury is the planet closest to the Sun, the only terrestrial planet besides Earth with a self-sustained magnetic field, and the smallest planet in our Solar System. It is a key planet for understanding the evolutionary history of our Solar System and therefore also for the question of how the Earth and our Planetary System were formed.The scientific objectives focus on a global characterization of Mercury through the investigation of its interior, surface, exosphere, and magnetosphere. In addition, instrumentation onboard BepiColombo will be used to test Einstein’s theory of general relativity. Major effort was put into optimizing the scientific return of the mission by defining a payload such that individual measurements can be interrelated and complement each other.

ESA’s Campaign Activities in Support of Earth Observation Projects: A focus on validation

2021 ◽  
Author(s):  
Dirk Schüttemeyer ◽  
Tania Casal ◽  
Malcom Davidson ◽  
Matthias Drusch ◽  
Julia Kubanek ◽  
...  
Keyword(s):  
European Space Agency ◽  
Earth Observation ◽  
Validation Dataset ◽  
Comprehensive Understanding ◽  
Space Agency ◽  
Fundamental Information ◽  
Future Space ◽  
Satellite Missions ◽  
Measurement Campaigns

<p>In the framework of its Earth Observation Programmes the European Space Agency (ESA) carries out ground based and airborne campaigns to support geophysical algorithm developments, calibration/validation activities, simulation of future space-borne earth observation missions, as well as application developments related to remote sensing of the atmosphere, land, oceans, solid earth and cryosphere.</p><p>ESA has conducted over 150 airborne and ground based measurement campaigns in the last 37 years, of which more than 80 were carried out since 2005. During this period a large number of campaigns have supported the validation of ESA’s satellite missions including for example SMOS and CryoSat. Ongoing activities are focusing on e.g. Sentinel-5Precursor and the preparation of upcoming Earth Explorer missions such as BIOMASS, FLEX, and FORUM. These validation campaigns aim to provide fundamental information about the confidence of data products and their required uncertainties One challenge in this context is a comprehensive understanding and characterization of measurement uncertainty of the validation dataset and the spatial and temporal support or representativity of these.</p><p><span>We will provide an overview of applied strategies to tackle these aspects for existing satellite missions and outline concepts for future missions, and how these integrate into broader earth observation science strategies. In addition, we will highlight recent activities and outline planned activities for the coming years.</span></p><p> </p>

Nanoprobe Characterization of Soft SRAM bit Fails in Advanced Technologies

2019 ◽  
Author(s):  
Satish Kodali ◽  
Chen Zhe ◽  
Chong Khiam Oh
Keyword(s):  
Yield Loss ◽  
Performance Metrics ◽  
Root Cause ◽  
Advanced Technologies ◽  
Capacitance Voltage ◽  
Defect Localization ◽  
Cv Measurements ◽  
Lightly Doped Drain ◽  
Dc Characterization

Abstract Nanoprobing is one of the key characterization techniques for soft defect localization in SRAM. DC transistor performance metrics could be used to identify the root cause of the fail mode. One such case report where nanoprobing was applied to a wafer impacted by significant SRAM yield loss is presented in this paper where standard FIB cross-section on hard fail sites and top down delayered inspection did not reveal any obvious defects. The authors performed nanoprobing DC characterization measurements followed by capacitance-voltage (CV) measurements. Two probe CV measurement was then performed between the gate and drain of the device with source and bulk floating. The authors identified valuable process marginality at the gate to lightly doped drain overlap region. Physical characterization on an inline split wafer identified residual deposits on the BL contacts potentially blocking the implant. Enhanced cleans for resist removal was implemented as a fix for the fail mode.

Case Study and Fault Modeling for Wrong Redundancy Evaluation on DRAM Devices

2007 ◽  
Author(s):  
Martin Versen ◽  
Dorina Diaconescu ◽  
Jerome Touzel
Keyword(s):  
Failure Mode ◽  
Failure Modes ◽  
Fault Modeling ◽  
Mode Analysis ◽  
Root Cause ◽  
Failure Mode Analysis

Abstract The characterization of failure modes of DRAM is often straight forward if array related hard failures with specific addresses for localization are concerned. The paper presents a case study of a bitline oriented failure mode connected to a redundancy evaluation in the DRAM periphery. The failure mode analysis and fault modeling focus both on the root-cause and on the test aspects of the problem.

scholarly journals Detailed Modeling of Cork-Phenolic Ablators in Preparation for the Post-flight Analysis of the QARMAN Re-entry CubeSat

2021 ◽  
Author(s):  
Claudio Miccoli ◽  
Alessandro Turchi ◽  
Pierre Schrooyen ◽  
Domenic D’Ambrosio ◽  
Thierry Magin
Keyword(s):  
Fluid Dynamics ◽  
Thermal Protection ◽  
A Priori ◽  
European Space Agency ◽  
Thermal Response ◽  
Accurate Method ◽  
Navier Stokes ◽  
Advection Equation ◽  
High Enthalpy ◽  
Space Agency

AbstractThis work deals with the analysis of the cork P50, an ablative thermal protection material (TPM) used for the heat shield of the qarman Re-entry CubeSat. Developed for the European Space Agency (ESA) at the von Karman Institute (VKI) for Fluid Dynamics, qarman is a scientific demonstrator for Aerothermodynamic Research. The ability to model and predict the atypical behavior of the new cork-based materials is considered a critical research topic. Therefore, this work is motivated by the need to develop a numerical model able to respond to this demand, in preparation to the post-flight analysis of qarman. This study is focused on the main thermal response phenomena of the cork P50: pyrolysis and swelling. Pyrolysis was analyzed by means of the multi-physics Computational Fluid Dynamics (CFD) code argo, developed at Cenaero. Based on a unified flow-material solver, the Volume Averaged Navier–Stokes (VANS) equations were numerically solved to describe the interaction between a multi-species high enthalpy flow and a reactive porous medium, by means of a high-order Discontinuous Galerkin Method (DGM). Specifically, an accurate method to compute the pyrolysis production rate was implemented. The modeling of swelling was the most ambitious task, requiring the development of a physical model accounting for this phenomenon, for the purpose of a future implementation within argo. A 1D model was proposed, mainly based on an a priori assumption on the swelling velocity and the resolution of a nonlinear advection equation, by means of a Finite Difference Method (FDM). Once developed, the model was successfully tested through a matlab code, showing that the approach is promising and thus opening the way to further developments.

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