scholarly journals Metal Hydride Compressors with Gas-Gap Heat Switches: Concept, Development, Testing, and Space Flight Operation for the Planck Sorption Cryocoolers

Inorganics ◽  
2019 ◽  
Vol 7 (12) ◽  
pp. 139 ◽  
Author(s):  
Robert C. Bowman
Keyword(s):  
European Space Agency ◽  
Thermal Conductance ◽  
Liquid Hydrogen ◽  
Hydrogen Gas ◽  
Lessons Learned ◽  
Temperature Modulation ◽  
Infrared Sensors ◽  
Heating And Cooling ◽  
Space Agency ◽  
Gas Gap

Two closed-cycle cryogenic refrigerators were used to generate temperatures of ~18 K via evaporation of liquid hydrogen at the interfaces with radiofrequency and infrared sensors on an Earth-orbiting spacecraft that measured the anisotropy of the cosmic microwave background (CMB) during the European Space Agency (ESA) Planck Mission from June 2009 until October 2013. The liquid hydrogen phase was continuously generated in each Planck Sorption Cryocooler (PSC) by coupling a Joule–Thomson (J–T) expander to hydrogen gas initially pressurized to nominally 3000 kPa (i.e., ~30 bar) and subsequently discharged at pressure of 30 kPa (i.e., ~0.3 bar) by desorption and absorption using LaNi4.78Sn0.22Hx contained in six individual sorbent beds. The pressures were varied by alternately heating and cooling this hydride that included temperature modulation with an integrated Gas-Gap Heat Switch (GGHS). The novel GGHS used the low-pressure hydride ZrNiHx to vary thermal conductance between the bed containing the LaNi4.78Sn0.22Hx sorbent and the rest of the compressor system. The design features and development of these hydride components are described along with details of fabrication and assembly. The results obtained during extended laboratory testing are also summarized. The predictions from this preflight testing are compared to the performance observed while operating in orbit during the Planck Mission. This review ends with a summary of lessons learned and recommendations for improved systems.

scholarly journals Development of Embedded Boot Software for a Satellite Instrument Control Unit: Lessons Learned

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Jesús Fernández-Conde ◽  
Jaime Gómez-Saez-de-Tejada ◽  
David Pérez-Lizán ◽  
Rafael Toledo-Moreo
Keyword(s):  
Real Time ◽  
European Space Agency ◽  
Control Unit ◽  
Lessons Learned ◽  
System Failure ◽  
Application Software ◽  
Satellite Mission ◽  
Space Agency ◽  
Expected Performance ◽  
Instrument Control

A satellite spacecraft is generally composed of a central Control and Data Management Unit (CDMU) and several instruments, each one locally controlled by its Instrument Control Unit (ICU). Inside each ICU, the embedded boot software (BSW) is the very first piece of software executed after power-up or reset. The ICU BSW is a nonpatchable, stand-alone, real-time software package that initializes the ICU HW, performs self-tests, and waits for CDMU commands to maintain on-board memory and ultimately start a patchable application software (ASW), which is responsible for execution of the nominal tasks assigned to the ICU (control of the satellite instrument being the most important one). The BSW is a relatively small but critical software item, since an unexpected behaviour can cause or contribute to a system failure resulting in fatal consequences such as the satellite mission loss. The development of this kind of embedded software is special in many senses, primarily due to its criticality, real-time expected performance, and the constrained size of program and data memories. This paper presents the lessons learned in the development and HW/SW integration phases of a satellite ICU BSW designed for a European Space Agency mission.

scholarly journals Robotic experiments with cooperative Aerobots and underwater swarms

Robotica ◽  
2009 ◽  
Vol 27 (1) ◽  
pp. 37-49 ◽  
Author(s):  
Ehsan Honary ◽  
Frank McQuade ◽  
Roger Ward ◽  
Ian Woodrow ◽  
Andy Shaw ◽  
...  
Keyword(s):  
Computer Simulations ◽  
Real World ◽  
European Space Agency ◽  
Underwater Vehicles ◽  
Lessons Learned ◽  
Data Handling ◽  
The Real ◽  
Unmanned Underwater Vehicles ◽  
Space Agency ◽  
Processing Power

SUMMARYSciSys has been involved in the development of Planetary Aerobots (arial robots) funded by the European Space Agency for use on Mars and has developed image-based localisation technology as part of the activity. However, it is possible to use Aerobots in a different environment to investigate issues regarding robotics behaviour, such as data handling, limited processing power, and limited sensors. This paper summarises the activity where an Aerobot platform was used to investigate the use of multiple autonomous unmanned underwater vehicles (UUVs) by simulating their movement and behaviour. It reports on the computer simulations and the real-world tests carried out and the lessons learned from these experiments.

scholarly journals The operational cloud retrieval algorithms from TROPOMI on board Sentinel-5 Precursor

2017 ◽  
Author(s):  
Diego G. Loyola ◽  
Sebastián Gimeno García ◽  
Ronny Lutz ◽  
Fabian Romahn ◽  
Robert J. D. Spurr ◽  
...  
Keyword(s):  
European Space Agency ◽  
Recognition Algorithm ◽  
Trace Gas ◽  
Infrared Sensors ◽  
Cloud Parameters ◽  
Cloud Properties ◽  
Low Clouds ◽  
Space Agency ◽  
Retrieval Algorithms ◽  
Data Record

Abstract. This paper presents the operational cloud retrieval algorithms for the TROPOspheric Monitoring Instrument (TROPOMI) on board the European Space Agency Sentinel-5 Precursor (S5P) mission scheduled for launch in 2017. Two algorithms working in tandem are used for retrieving cloud properties: OCRA (Optical Cloud Recognition Algorithm) and ROCINN (Retrieval of Cloud Information using Neural Networks). OCRA retrieves the cloud fraction using TROPOMI measurements in the UV/VIS spectral regions and ROCINN retrieves the cloud top height (pressure) and optical thickness (albedo) using TROPOMI measurements in and around the oxygen A-band in the NIR. Cloud parameters from TROPOMI/S5P will be used not only for enhancing the accuracy of trace gas retrievals, but also for extending the satellite data record of cloud information derived from oxygen A-band measurements, a record initiated with GOME/ERS-2 over twenty years ago. Use of the oxygen A-band generates complementary cloud information (especially for low clouds), as compared to traditional thermal infrared sensors (as used in most meteorological satellites) that are less sensitive to low clouds due to reduced thermal contrast. The OCRA and ROCINN algorithms are integrated in the S5P operational processor UPAS (Universal Processor for UV/VIS/NIR Atmospheric Spectrometers), and we present here UPAS cloud results using OMI and GOME-2 measurements. In addition, we examine anticipated challenges for the TROPOMI/S5P cloud retrieval algorithms and we discuss the future validation needs for OCRA and ROCINN.

Developing the Planck Mission Simulation as a Multi-Platform Immersive Application

2011 ◽  
Author(s):  
Gerald A. Dekker ◽  
John Moreland ◽  
Jatila van der Veen
Keyword(s):  
European Space Agency ◽  
Data Gathering ◽  
Lessons Learned ◽  
Microwave Background ◽  
The Public ◽  
Systems Implementation ◽  
Space Agency ◽  
Accuracy And Precision ◽  
Technical Details ◽  
Mission Simulation

Planck is an international mission led by the European Space Agency with significant contribution by NASA, designed to measure the anisotropy of the Cosmic Microwave Background (CMB), the oldest radiation of the universe, with the greatest accuracy and precision of any such CMB experiment to date. The present work was completed as part of the Planck Education and Public Outreach (E/PO) effort to communicate the results of Planck science to the public. The Planck Mission Simulation is a multiplatform, interactive visualization of the mission, from launch to orbital insertion to data gathering operations. The simulation was developed for a number of hardware and software configurations. Originally designed for a multi-screen virtual reality system, the scope of project grew to include other systems, including 3D kiosk displays, stereoscopic televisions, and domed-roomed systems. Implementation factors, technical details, and lessons learned from deployment on various platforms are discussed.

scholarly journals Spacecraft collision avoidance challenge: Design and results of a machine learning competition

Astrodynamics ◽  
2021 ◽  
Author(s):  
Thomas Uriot ◽  
Dario Izzo ◽  
Luís F. Simões ◽  
Rasit Abay ◽  
Nils Einecke ◽  
...  
Keyword(s):  
Machine Learning ◽  
Collision Avoidance ◽  
Risk Mitigation ◽  
European Space Agency ◽  
Close Approach ◽  
Lessons Learned ◽  
Mitigation Measures ◽  
Collision Risk ◽  
Problem Domain ◽  
Space Agency

AbstractSpacecraft collision avoidance procedures have become an essential part of satellite operations. Complex and constantly updated estimates of the collision risk between orbiting objects inform various operators who can then plan risk mitigation measures. Such measures can be aided by the development of suitable machine learning (ML) models that predict, for example, the evolution of the collision risk over time. In October 2019, in an attempt to study this opportunity, the European Space Agency released a large curated dataset containing information about close approach events in the form of conjunction data messages (CDMs), which was collected from 2015 to 2019. This dataset was used in the Spacecraft Collision Avoidance Challenge, which was an ML competition where participants had to build models to predict the final collision risk between orbiting objects. This paper describes the design and results of the competition and discusses the challenges and lessons learned when applying ML methods to this problem domain.

Deploying Interactive Mission Planning Tools- Experiences and Lessons Learned -

2011 ◽  
Vol 15 (8) ◽  
pp. 1149-1158 ◽  
Author(s):  
Amedeo Cesta ◽  
◽  
Gabriella Cortellessa ◽  
Simone Fratini ◽  
Angelo Oddi ◽  
...  
Keyword(s):  
Problem Solving ◽  
European Space Agency ◽  
User Interaction ◽  
Work Practice ◽  
Lessons Learned ◽  
Mission Planning ◽  
Domain Modeling ◽  
Planning And Scheduling ◽  
Space Agency ◽  
Key Points

This article contains a retrospective overview of connected work performed for the European Space Agency (ESA) over a span of 10 years. We have been creating and refining an AI approach to problem solving and have infused a series of deployed planning and scheduling systems which have innovated the agency’s mission planning practice. The goal of this paper is to identify strong features of this experience, comment on general lessons learned and offer guidelines for work practice of the future. Specifically, the work considers some key points that have contributed to strengthening the effectiveness of our approach for the development of an end-to-end methodology to field applications: the attention to domain modeling, the constraint-based algorithm synthesis and the relevance of user interaction services.

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.

scholarly journals Applicability of NGGM near-real time simulations in flood detection

2019 ◽  
Vol 9 (1) ◽  
pp. 111-126
Author(s):  
A. F. Purkhauser ◽  
J. A. Koch ◽  
R. Pail
Keyword(s):  
European Space Agency ◽  
Earth System ◽  
The Earth ◽  
Future Mission ◽  
Space Agency ◽  
Flood Detection ◽  
The One ◽  
Real Time Simulations ◽  
Grace Mission ◽  
Gravity Mission

Abstract The GRACE mission has demonstrated a tremendous potential for observing mass changes in the Earth system from space for climate research and the observation of climate change. Future mission should on the one hand extend the already existing time series and also provide higher spatial and temporal resolution that is required to fulfil all needs placed on a future mission. To analyse the applicability of such a Next Generation Gravity Mission (NGGM) concept regarding hydrological applications, two GRACE-FO-type pairs in Bender formation are analysed. The numerical closed loop simulations with a realistic noise assumption are based on the short arc approach and make use of the Wiese approach, enabling a self-de-aliasing of high-frequency atmospheric and oceanic signals, and a NRT approach for a short latency. Numerical simulations for future gravity mission concepts are based on geophysical models, representing the time-variable gravity field. First tests regarding the usability of the hydrology component contained in the Earth System Model (ESM) by the European Space Agency (ESA) for the analysis regarding a possible flood monitoring and detection showed a clear signal in a third of the analysed flood cases. Our analysis of selected cases found that detection of floods was clearly possible with the reconstructed AOHIS/HIS signal in 20% of the tested examples, while in 40% of the cases a peak was visible but not clearly recognisable.

scholarly journals Prisma: A New Space Mission For Stellar Physics

1993 ◽  
Vol 137 ◽  
pp. 812-819
Author(s):  
T. Appourchaux ◽  
D. Gough ◽  
P. Hyoyng ◽  
C. Catala ◽  
S. Frandsen ◽  
...  
Keyword(s):  
European Space Agency ◽  
Real Space ◽  
Space Mission ◽  
Economic Conditions ◽  
X Ray ◽  
Space Agency ◽  
New Space

PRISMA (Probing Rotation and Interior of Stars: Microvariability and Activity) is a new space mission of the European Space Agency. PRISMA is currently in a Phase A study with 3 other competitors. PRISMA is the only ESA-only mission amongst those four and only one mission will be selected in Spring 1993 to become a real space mission.The goal of the Phase A study is to determine whether the payload of PRISMA can be accommodated on a second unit of the X-ray Multi-Mirror (XMM) bus; and whether the budget of the PRISMA mission can be kept below 265 MAU (’88 Economic conditions). The XMM mission is an approved cornerstone and is in a Phase A together with PRISMA.

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