Exosat for Ground-based Observers

1982 ◽  
Vol 4 (4) ◽  
pp. 458-460
Author(s):  
A. B. Giles
Keyword(s):  
Early Stage ◽  
European Space Agency ◽  
The Other ◽  
Baseline Design ◽  
X Ray ◽  
Stage Of Development ◽  
Space Agency ◽  
Changing Role ◽  
Unique Capability

The first version of this mission was approved by the European Space Agency (ESA) Council in 1973 but did not infact start its Phase B study until 1977. The early baseline design had been constrained by the requirement to make the spacecraft compatible in size and weight with the performance of a NASA Delta rocket, since this was seen as a necessary back-up to Ariane, then at an early stage of development. The mission payload then evolved with time due to the changing role dictated by the technical successes and observations made by the series of well-known X-ray satellites. The final spacecraft has emerged to have a unique capability since all the other X-ray satellites except the small Hakucho have now expired.

The Application of UX Research in New Energy Vehicle Innovation

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Menghan TAO ◽  
Ning XIAO ◽  
Xingfu ZHAO ◽  
Wenbin LIU
Keyword(s):  
Early Stage ◽  
Rapid Expansion ◽  
The Other ◽  
Innovative Product ◽  
Stage Of Development ◽  
New Energy ◽  
New Energy Vehicle ◽  
The One ◽  
New Energy Vehicles ◽  
Degree Of Innovation

New energy vehicles(NEV) as a new thing for sustainable development, in China, on the one hand has faced the rapid expansion of the market; the other hand, for the new NEV users, the current NEVs cannot keep up with the degree of innovation. This paper demonstrates the reasons for the existence of this systematic challenge, and puts forward the method of UX research which is different from the traditional petrol vehicles research in the early stage of development, which studies from the user's essence level, to form the innovative product programs which meet the needs of users and being real attractive.

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.

scholarly journals OLCI A/B Tandem Phase Analysis, Part 1: Level 1 Homogenisation and Harmonisation

2020 ◽  
Vol 12 (11) ◽  
pp. 1804 ◽  
Author(s):  
Nicolas Lamquin ◽  
Sébastien Clerc ◽  
Ludovic Bourg ◽  
Craig Donlon
Keyword(s):  
European Space Agency ◽  
Companion Paper ◽  
The Other ◽  
Satellite Mission ◽  
Space Agency ◽  
The Future ◽  
Level 1 ◽  
Level 2 ◽  
Very High ◽  
Sentinel 2

Copernicus is a European system for monitoring the Earth in support of European policy. It includes the Sentinel-3 satellite mission which provides reliable and up-to-date measurements of the ocean, atmosphere, cryosphere, and land. To fulfil mission requirements, two Sentinel-3 satellites are required on-orbit at the same time to meet revisit and coverage requirements in support of Copernicus Services. The inter-unit consistency is critical for the mission as more S3 platforms are planned in the future. A few weeks after its launch in April 2018, the Sentinel-3B satellite was manoeuvred into a tandem configuration with its operational twin Sentinel-3A already in orbit. Both satellites were flown only thirty seconds apart on the same orbit ground track to optimise cross-comparisons. This tandem phase lasted from early June to mid October 2018 and was followed by a short drift phase during which the Sentinel-3B satellite was progressively moved to a specific orbit phasing of 140° separation from the sentinel-3A satellite. In this paper, an output of the European Space Agency (ESA) Sentinel-3 Tandem for Climate study (S3TC), we provide a full methodology for the homogenisation and harmonisation of the two Ocean and Land Colour Instruments (OLCI) based on the tandem phase. Homogenisation adjusts for unavoidable slight spatial and spectral differences between the two sensors and provide a basis for the comparison of the radiometry. Persistent radiometric biases of 1–2% across the OLCI spectrum are found with very high confidence. Harmonisation then consists of adjusting one instrument on the other based on these findings. Validation of the approach shows that such harmonisation then procures an excellent radiometric alignment. Performed on L1 calibrated radiances, the benefits of harmonisation are fully appreciated on Level 2 products as reported in a companion paper. Whereas our methodology aligns one sensor to behave radiometrically as the other, discussions consider the choice of the reference to be used within the operational framework. Further exploitation of the measurements indeed provides evidence of the need to perform flat-fielding on both payloads, prior to any harmonisation. Such flat-fielding notably removes inter-camera differences in the harmonisation coefficients. We conclude on the extreme usefulness of performing a tandem phase for the OLCI mission continuity as well as for any optical mission to which the methodology presented in this paper applies (e.g., Sentinel-2). To maintain the climate record, it is highly recommended that the future Sentinel-3C and Sentinel-3D satellites perform tandem flights when injected into the Sentinel-3 time series.

scholarly journals A comparison between the two lobes of comet 67P/Churyumov–Gerasimenko based on D/H ratios in H2O measured with the Rosetta/ROSINA DFMS

2019 ◽  
Vol 489 (4) ◽  
pp. 4734-4740 ◽  
Author(s):  
Isaac R H G Schroeder ◽  
Kathrin Altwegg ◽  
Hans Balsiger ◽  
Jean-Jacques Berthelier ◽  
Michael R Combi ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
European Space Agency ◽  
Cometary Nucleus ◽  
The Other ◽  
Appreciable Difference ◽  
Space Agency ◽  
Close Proximity ◽  
Double Focusing ◽  
Comet 67P

ABSTRACT The nucleus of the Jupiter-family comet 67P/Churyumov–Gerasimenko was discovered to be bi-lobate in shape when the European Space Agency spacecraft Rosetta first approached it in 2014 July. The bi-lobate structure of the cometary nucleus has led to much discussion regarding the possible manner of its formation and on how the composition of each lobe might compare with that of the other. During its two-year-long mission from 2014 to 2016, Rosetta remained in close proximity to 67P/Churyumov–Gerasimenko, studying its coma and nucleus in situ. Based on lobe-specific measurements of HDO and H2O performed with the ROSINA Double Focusing Mass Spectrometer (DFMS) on board Rosetta, the deuterium-to-hydrogen (D/H) ratios in water from the two lobes can be compared. No appreciable difference was observed, suggesting that both lobes formed in the same region and are homogeneous in their D/H ratios.

scholarly journals AIDA: Asteroid Impact and Deflection Assessment

2012 ◽  
Vol 10 (H16) ◽  
pp. 480-480 ◽  
Author(s):  
Patrick Michel ◽  
A. Cheng ◽  
A. Galvez ◽  
C. Reed ◽  
I. Carnelli ◽  
...  
Keyword(s):  
European Space Agency ◽  
The Other ◽  
Applied Physics ◽  
Binary Asteroid ◽  
Jet Propulsion ◽  
Asteroid Impact ◽  
Space Agency ◽  
Goddard Space Flight Center ◽  
Asteroid Deflection ◽  
Joint Mission

AbstractAIDA (Asteroid Impact and Deflection Assessment) is a project of a joint mission demonstration of asteroid deflection and characterisation of the kinetic impact effects. It involves the Johns Hopkins Applied Physics Laboratory (with support from members of NASA centers including Goddard Space Flight Center, Johnson Space Center, and the Jet Propulsion Laboratory), and the European Space Agency (with support from members of the french CNRS/Cte dAzur Observatory and the german DLR). This assessment will be done using a binary asteroid target. AIDA consists of two independent but mutually supporting mission concepts, one of which is the asteroid kinetic impactor and the other is the characterisation spacecraft. The objective and status of the project will be presented.

scholarly journals Detection capabilities of the Athena X-IFU for the warm-hot intergalactic medium using gamma-ray burst X-ray afterglows

2020 ◽  
Vol 642 ◽  
pp. A24
Author(s):  
Sarah Walsh ◽  
Sheila McBreen ◽  
Antonio Martin-Carrillo ◽  
Thomas Dauser ◽  
Nastasha Wijers ◽  
...  
Keyword(s):  
Large Scale ◽  
Intergalactic Medium ◽  
Gamma Ray ◽  
Statistical Significance ◽  
European Space Agency ◽  
Gamma Ray Burst ◽  
X Ray ◽  
Baryonic Density ◽  
Space Agency ◽  
High Statistical Significance

At low redshifts, the observed baryonic density falls far short of the total number of baryons predicted. Cosmological simulations suggest that these baryons reside in filamentary gas structures, known as the warm-hot intergalactic medium (WHIM). As a result of the high temperatures of these filaments, the matter is highly ionised such that it absorbs and emits far-UV and soft X-ray photons. Athena, the proposed European Space Agency X-ray observatory, aims to detect the “missing” baryons in the WHIM up to redshifts of z = 1 through absorption in active galactic nuclei and gamma-ray burst (GRB) afterglow spectra, allowing for the study of the evolution of these large-scale structures of the Universe. This work simulates WHIM filaments in the spectra of GRB X-ray afterglows with Athena using the SImulation of X-ray TElescopes framework. We investigate the feasibility of their detection with the X-IFU instrument, through O VII (E = 573 eV) and O VIII (E = 674 eV) absorption features, for a range of equivalent widths imprinted onto GRB afterglow spectra of observed starting fluxes ranging between 10−12 and 10−10 erg cm−2 s−1, in the 0.3−10 keV energy band. The analyses of X-IFU spectra by blind line search show that Athena will be able to detect O VII−O VIII absorption pairs with EWO VII > 0.13 eV and EWO VIII > 0.09 eV for afterglows with F > 2 × 10−11 erg cm−2 s−1. This allows for the detection of ≈ 45−137 O VII−O VIII absorbers during the four-year mission lifetime. The work shows that to obtain an O VII−O VIII detection of high statistical significance, the local hydrogen column density should be limited at NH < 8 × 1020 cm−2.

scholarly journals Spherical analyzers and monochromators for resonant inelastic hard X-ray scattering: a compilation of crystals and reflections

2012 ◽  
Vol 20 (1) ◽  
pp. 74-79 ◽  
Author(s):  
Thomas Gog ◽  
Diego M. Casa ◽  
Ayman H. Said ◽  
Mary H. Upton ◽  
Jungho Kim ◽  
...  
Keyword(s):  
High Resolution ◽  
Lithium Niobate ◽  
Silicon Germanium ◽  
Early Stage ◽  
Double Crystal ◽  
Actual Performance ◽  
X Ray ◽  
Stage Of Development ◽  
X Ray Scattering ◽  
Ray Scattering

Resonant inelastic X-ray scattering (RIXS) experiments require special sets of near-backscattering spherical diced analyzers and high-resolution monochromators for every distinct absorption-edge energy and emission line. For the purpose of aiding the design and planning of efficient RIXS experiments, comprehensive lists of suitable analyzer reflections for silicon, germanium, α-quartz, sapphire and lithium niobate crystals were compiled for a multitude of absorption edges and emission lines. Analyzers made from lithium niobate, sapphire or α-quartz offer many choices of reflections with intrinsic resolutions currently unattainable from silicon or germanium. In some cases these materials offer higher intensities at comparable resolutions. While lithium niobate, sapphire or α-quartz analyzers are still in an early stage of development, the present compilation can serve as a computational basis for assessing expected and actual performance. With regard to high-resolution monochromators, bandpass and throughput calculations for combinations of double-crystal, high-heat-load and near-backscattering high-resolution channel-cuts were assembled. The compilation of these analyzer and monochromator data is publicly available on a website.

scholarly journals An Evaluation Matrix to Compare Computer Hydrological Models for Flood Predictions

Hydrology ◽  
2020 ◽  
Vol 7 (3) ◽  
pp. 42 ◽  
Author(s):  
Pasquale Filianoti ◽  
Luana Gurnari ◽  
Demetrio Antonio Zema ◽  
Giuseppe Bombino ◽  
Marco Sinagra ◽  
...  
Keyword(s):  
Prediction Accuracy ◽  
Early Stage ◽  
Optimal Choice ◽  
Evaluation Framework ◽  
The Other ◽  
Hydrological Models ◽  
Complete Evaluation ◽  
Flood Prediction ◽  
Stage Of Development ◽  
Performance Matrix

In order to predict and control the impacts of floods in torrents, it is important to verify the simulation accuracy of the most used hydrological models. The performance verification is particularly needed for applications in watersheds with peculiar climatic and geomorphological characteristics, such as the Mediterranean torrents. Moreover, in addition to the accuracy, other factors affect the choice of software by stakeholders (users, modellers, researchers, etc.). This study introduces a “performance matrix”, consisting of several evaluation parameters weighted by stakeholders’ opinions. The aim is to evaluate the accuracy of the flood prediction which is achieved by different models, as well as the pros and cons of software user experience. To this aim, the performances and requisites of four physical-based and conceptual models (HEC-HMS, SWMM, MIKE11 NAM and WEC-FLOOD) have been evaluated, by predicting floods in a midsized Mediterranean watershed (Mèsima torrent, Calabria, Southern Italy). In the case study, HEC-HMS and MIKE 11 NAM were the best computer models (with a weighted score of 4.45 and 4.43, respectively), thanks to their low complexity and computation effort, as well as good user interface and prediction accuracy. However, MIKE11 NAM is not free of charge. SWMM showed a lower prediction accuracy, which put the model in third place of the four models. The performance of WEC-FLOOD, although not being as good as for the other tested models, can be considered overall acceptable in comparison to the other well-consolidated models, considering that WEC-FLOOD is in the early stage of development. Overall, the proposal of the performance matrix for hydrological models may represent a first step in building a more complete evaluation framework of the hydrological and hydraulic commercial models, in order to give indications to allow potential users to make an optimal choice.

scholarly journals Achievements of Hinode in the first eleven years

2019 ◽  
Vol 71 (5) ◽  
Author(s):  
◽  
Khalid Al-Janabi ◽  
Patrick Antolin ◽  
Deborah Baker ◽  
Luis R Bellot Rubio ◽  
...  
Keyword(s):  
Solar Physics ◽  
European Space Agency ◽  
Review Article ◽  
Future Prospects ◽  
Optical Telescope ◽  
Imaging Spectrometer ◽  
X Ray ◽  
Space Agency ◽  
The Uk ◽  
Euv Imaging

Abstract Hinode is Japan’s third solar mission following Hinotori (1981–1982) and Yohkoh (1991–2001): it was launched on 2006 September 22 and is in operation currently. Hinode carries three instruments: the Solar Optical Telescope, the X-Ray Telescope, and the EUV Imaging Spectrometer. These instruments were built under international collaboration with the National Aeronautics and Space Administration and the UK Science and Technology Facilities Council, and its operation has been contributed to by the European Space Agency and the Norwegian Space Center. After describing the satellite operations and giving a performance evaluation of the three instruments, reviews are presented on major scientific discoveries by Hinode in the first eleven years (one solar cycle long) of its operation. This review article concludes with future prospects for solar physics research based on the achievements of Hinode.

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