The Lyman Far Ultraviolet Spectroscopic Mission (Invited Paper)

1987 ◽  
Vol 7 (2) ◽  
pp. 173-184 ◽  
Author(s):  
Ian R. Tuohy ◽  
Michael A. Dopita
Keyword(s):  
Molecular Hydrogen ◽  
Extreme Ultraviolet ◽  
European Space Agency ◽  
Light Element ◽  
Grazing Incidence ◽  
Spectral Lines ◽  
Important Species ◽  
Element Abundances ◽  
Space Agency ◽  
Far Ultraviolet

AbstractThe Lyman mission will undertake the first sensitive high resolution spectroscopic observations in the largely unexplored 912-1216Å region. This astrophysically critical wavelength interval is exceedingly rich in diagnostic spectral lines such as the Lyman series of atomic hydrogen and deuterium, the Lyman and Werner bands of molecular hydrogen and deuterium, and the resonance lines of numerous important species including CIII, NI-III and OVI. Lyman will have a major impact in all areas of modern astrophysics, with the most fundamental contribution being the determination of light element abundances in the local interstellar medium and in the intergalactic medium at low redshift. The mapping of hot gas (T ∼ 3 × 105K) and molecular hydrogen and HD in the disk and halo of our galaxy represent additional major objectives for which Lyman is uniquely qualified.The Lyman payload will comprise a grazing incidence telescope and three spectroscopic instruments: the prime spectrograph operating between 912-1250Å with a resolution of λ/ Δλ ∼ 30,000, a far ultraviolet spectrograph (1200-2000Å;λ/ Δλ ∼ 10,000), and an extreme ultraviolet spectrograph (100-900Å; λ /Δλ ∼ 300). Observations will be conducted from a highly efficient 48 hour elliptical orbit which will allow long un-interrupted exposures and real time operations. It is anticipated that Lyman will be launched by Ariane in 1996, and will have an operational lifetime of at least 5 years. Data reception and spacecraft control will be undertaken from ground stations in Spain and in Australia.Lyman is currently being studied at Phase-A level by Australia in close coordination with the European Space Agency. The scientific involvement is the responsibility of the Lyman Science Working Group, composed of members representing the various astronomical institutions in Australia. Funding to support the technical and scientific aspects of the mission is provided via the Australian Space Board and the Department of Industry, Technology and Commerce in recognition of the major opportunity that Lyman presents to the Australian aerospace industry.

Spectral Observations of the Extreme Ultraviolet Astronomical Background Radiation

1988 ◽  
Vol 102 ◽  
pp. 63-66
Author(s):  
S. Labov ◽  
S. Bowyer
Keyword(s):  
Interstellar Medium ◽  
Background Radiation ◽  
Extreme Ultraviolet ◽  
Grazing Incidence ◽  
Sounding Rocket ◽  
Interstellar Space ◽  
Spectral Measurements ◽  
Interstellar Gas ◽  
Hot Plasma ◽  
Far Ultraviolet

AbstractObservations in the far ultraviolet and soft x-ray bands suggest that the interstellar medium contains several components of high temperature gas (105to 106K). If large volumes of local interstellar space are filled with this hot plasma, emission lines will be produced in the extreme ultraviolet (EUV). Diffuse EUV radiation, however, has only been detected with photometric instruments; no spectral measurements exist below 520Å. We have designed a unique grazing incidence spectrometer to study the diffuse emission between 80 and 650Å with 10 to 30Å resolution. This instrument was successfully flown on a sounding rocket in April of 1986 and a preliminary analysis reveals several features. In addition to the expected interplanetary He I 584Å emission and the geocoronal He II 304Å emission, other features appear which may originate in the hot ionized interstellar gas. These features are discussed along with the possible implications to the hot phase of the interstellar medium.

Spectroscopic analysis of M- and N-intrashell transitions in Co-like to Na-like Yb ions

2021 ◽  
Author(s):  
Roshani Silwal ◽  
Dipti Dipti ◽  
Endre Takacs ◽  
Joan M. Dreiling ◽  
Samuel C Sanders ◽  
...  
Keyword(s):  
Electron Beam ◽  
Magnetic Dipole ◽  
Large Scale ◽  
Ion Trap ◽  
Extreme Ultraviolet ◽  
Wavelength Region ◽  
Grazing Incidence ◽  
Spectral Lines ◽  
Electron Beam Ion Trap ◽  
Large Scale Simulations

Abstract The M-intrashell spectra from Co-like Yb43+ through Na-like Yb59+ ions produced in an electron beam ion trap (EBIT) at the National Institute of Standards and Technology have been studied in the extreme ultraviolet (EUV) range. A few N-intrashell transitions for Co-like Yb43+ and Fe-like Yb44+ are also reported. The EUV radiation was observed with a flat-field grazing incidence spectrometer in the wavelength region of about 7.5 nm to 26.2 nm. The electron beam energies were varied between 3.6 keV and 18 keV to produce the ionization stages of interest. The line identifications were based on the large-scale simulations of the EBIT plasma emission using the non-Maxwellian collisional-radiative code NOMAD. A total of 76 previously unobserved spectral lines corresponding to electric-dipole and magnetic-dipole transitions in the above mentioned ions were identified and discussed. In particular, our accurate wavelength of 24.3855±0.0005 nm for a magnetic-dipole (M1) transition in the ground configuration of Co-like ion presents a solid benchmark for comparisons with the most advanced theories of atomic structure.

scholarly journals The Herschel SPIRE Fourier Transform Spectrometer Spectral Feature Finder – III. Line identification and off-axis spectra

2020 ◽  
Vol 496 (4) ◽  
pp. 4906-4922 ◽  
Author(s):  
Chris S Benson ◽  
N Hładczuk ◽  
L D Spencer ◽  
A Robb ◽  
J Scott ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Signal To Noise Ratio ◽  
European Space Agency ◽  
Spectral Feature ◽  
Spectral Lines ◽  
Spectral Features ◽  
Fourier Transform Spectrometer ◽  
Line Identification ◽  
Space Agency ◽  
Feature Fitting

ABSTRACT The European Space Agency Herschel Spectral and Photometric Imaging Receiver (SPIRE) Fourier Transform Spectrometer (FTS) Spectral Feature Finder (FF) project is an automated spectral feature fitting routine developed within the SPIRE instrument team to extract all prominent spectral features from all publicly available SPIRE FTS observations. We present the extension of the FF to include the off-axis detectors of the FTS in sparsely sampled single-pointing observations, the results of which have been ingested into the catalogue. We also present the results from an automated routine for identifications of the atomic/molecular transitions that correspond to the spectral features extracted by the FF. We use a template of 307 atomic fine structure and molecular lines that are commonly found in SPIRE FTS spectra for the cross-match. The routine makes use of information provided by the line identification to search for low signal-to-noise ratio features that have been excluded or missed by the iterative FF. In total, the atomic/molecular transitions of 178 942 lines are identified (corresponding to 83 per cent of the entire FF catalogue), and an additional 33 840 spectral lines associated with missing features from SPIRE FTS observations are added to the FF catalogue.

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.

scholarly journals BepiColombo Science Investigations During Cruise and Flybys at the Earth, Venus and Mercury

2021 ◽  
Vol 217 (1) ◽  
Author(s):  
Valeria Mangano ◽  
Melinda Dósa ◽  
Markus Fränz ◽  
Anna Milillo ◽  
Joana S. Oliveira ◽  
...  
Keyword(s):  
French Guiana ◽  
European Space Agency ◽  
Scientific Research ◽  
The Earth ◽  
Space Agency ◽  
Spacecraft Mission ◽  
Joint Mission ◽  
Science Investigations ◽  
Orbit Insertion ◽  
Inner Heliosphere

AbstractThe dual spacecraft mission BepiColombo is the first joint mission between the European Space Agency (ESA) and the Japanese Aerospace Exploration Agency (JAXA) to explore the planet Mercury. BepiColombo was launched from Kourou (French Guiana) on October 20th, 2018, in its packed configuration including two spacecraft, a transfer module, and a sunshield. BepiColombo cruise trajectory is a long journey into the inner heliosphere, and it includes one flyby of the Earth (in April 2020), two of Venus (in October 2020 and August 2021), and six of Mercury (starting from 2021), before orbit insertion in December 2025. A big part of the mission instruments will be fully operational during the mission cruise phase, allowing unprecedented investigation of the different environments that will encounter during the 7-years long cruise. The present paper reviews all the planetary flybys and some interesting cruise configurations. Additional scientific research that will emerge in the coming years is also discussed, including the instruments that can contribute.

scholarly journals Gaia Data Release 2

2018 ◽  
Vol 616 ◽  
pp. A2 ◽  
Author(s):  
L. Lindegren ◽  
J. Hernández ◽  
A. Bombrun ◽  
S. Klioner ◽  
U. Bastian ◽  
...  
Keyword(s):  
Proper Motion ◽  
Input Data ◽  
European Space Agency ◽  
Iterative Solution ◽  
Spatial Correlations ◽  
Satellite Attitude ◽  
Space Agency ◽  
Data Release ◽  
Ccd Observations ◽  
Celestial Reference System

Context. Gaia Data Release 2 (Gaia DR2) contains results for 1693 million sources in the magnitude range 3 to 21 based on observations collected by the European Space Agency Gaia satellite during the first 22 months of its operational phase. Aims. We describe the input data, models, and processing used for the astrometric content of Gaia DR2, and the validation of these resultsperformed within the astrometry task. Methods. Some 320 billion centroid positions from the pre-processed astrometric CCD observations were used to estimate the five astrometric parameters (positions, parallaxes, and proper motions) for 1332 million sources, and approximate positions at the reference epoch J2015.5 for an additional 361 million mostly faint sources. These data were calculated in two steps. First, the satellite attitude and the astrometric calibration parameters of the CCDs were obtained in an astrometric global iterative solution for 16 million selected sources, using about 1% of the input data. This primary solution was tied to the extragalactic International Celestial Reference System (ICRS) by means of quasars. The resulting attitude and calibration were then used to calculate the astrometric parameters of all the sources. Special validation solutions were used to characterise the random and systematic errors in parallax and proper motion. Results. For the sources with five-parameter astrometric solutions, the median uncertainty in parallax and position at the reference epoch J2015.5 is about 0.04 mas for bright (G < 14 mag) sources, 0.1 mas at G = 17 mag, and 0.7 masat G = 20 mag. In the proper motion components the corresponding uncertainties are 0.05, 0.2, and 1.2 mas yr−1, respectively.The optical reference frame defined by Gaia DR2 is aligned with ICRS and is non-rotating with respect to the quasars to within 0.15 mas yr−1. From the quasars and validation solutions we estimate that systematics in the parallaxes depending on position, magnitude, and colour are generally below 0.1 mas, but the parallaxes are on the whole too small by about 0.03 mas. Significant spatial correlations of up to 0.04 mas in parallax and 0.07 mas yr−1 in proper motion are seen on small (< 1 deg) and intermediate (20 deg) angular scales. Important statistics and information for the users of the Gaia DR2 astrometry are given in the appendices.

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