scholarly journals Retrieval of ionospheric profiles from the Mars Express MARSIS experiment data and comparison with radio-occultation data

2012 ◽  
Vol 2 (1) ◽  
pp. 87-106
Author(s):  
B. Sánchez-Cano ◽  
O. Witasse ◽  
M. Herraiz ◽  
S. M. Radicella ◽  
J. Bauer ◽  
...  
Keyword(s):  
Radio Occultation ◽  
European Space Agency ◽  
Planetary Science ◽  
Data Set ◽  
Mars Express ◽  
Radio Science ◽  
Space Agency ◽  
Martian Ionosphere ◽  
Occultation Data ◽  
Ionospheric Sounding

Abstract. Since 2005 the Mars Advanced Radar and Ionospheric Sounding experiment (MARSIS) aboard Mars Express has acquired a unique data set on the ionosphere of Mars made up of ionospheric soundings taken by the instrument working in its Active Ionospheric Sounding (AIS) mode. These soundings play a role similar to those of modern Terrestrial digisondes in the analysis of our planet ionosphere and have allowed us to dramatically improve our knowledge about the Martian ionosphere. This paper describes this kind of data, which are available from the public Planetary Science Archive, and introduces the MAISDAT tool developed by the European Space Agency to analyze and derive the vertical profile of electron density. Comparisons with radio-occultation profiles obtained from Mars Express Radio Science instrument are performed to validate the procedure used in this study.

scholarly journals Retrieval of ionospheric profiles from the Mars Express MARSIS experiment data and comparison with radio occultation data

2012 ◽  
Vol 1 (1) ◽  
pp. 77-84 ◽  
Author(s):  
B. Sánchez-Cano ◽  
O. Witasse ◽  
M. Herraiz ◽  
S. M. Radicella ◽  
J. Bauer ◽  
...  
Keyword(s):  
Radio Occultation ◽  
European Space Agency ◽  
Planetary Science ◽  
Mars Express ◽  
Radio Science ◽  
The Public ◽  
Space Agency ◽  
Martian Ionosphere ◽  
Occultation Data ◽  
Ionospheric Sounding

Abstract. Since 2005 the Mars Advanced Radar and Ionospheric Sounding experiment (MARSIS) aboard Mars Express has acquired a unique dataset on the ionosphere of Mars made up of ionospheric soundings taken by the instrument working in its active ionospheric sounding (AIS) mode. These soundings play a role similar to those of modern Terrestrial digisondes in the analysis of our planet ionosphere and have allowed us to dramatically improve our knowledge about the Martian ionosphere. This paper describes this kind of data, which are available from the public Planetary Science Archive, and introduces the MAISDAT tool developed by the European Space Agency to analyze and derive the vertical profile of electron density. Comparisons with radio occultation profiles obtained from Mars Express Radio Science instrument are performed to validate the procedure used in this study.

scholarly journals Calibration Techniques for Studying Venus and Mars Atmospheres

2020 ◽  
Vol 99 (4) ◽  
pp. 255-261
Author(s):  
Edoardo Gramigna
Keyword(s):  
Radio Occultation ◽  
European Space Agency ◽  
Point Of View ◽  
Mars Atmosphere ◽  
Radio Science ◽  
Space Agency ◽  
Spacecraft Trajectory ◽  
Venus Express ◽  
Calibration Techniques ◽  
Venus Atmosphere

AbstractThe European Space Agency Venus Express mission (VEX) was sent to Venus in 2005 to unveil the unsolved mysteries regarding its atmosphere, the plasma environment and its temperatures. Radio occultation experiments performed by VeRa radio science instrument probed the planet’s atmosphere by studying the frequency shift on the radio signal sent by the spacecraft to Earth-based ground stations. This study carries out the calibration of the radio frequencies within a radio occultation experiment in order to correct the main sources of error as: thermal noise, spacecraft clock, spacecraft trajectory, and plasma noise. Any uncalibrated effects will bias the retrieval of atmospheric properties. A comparison of the occultation experiments between Venus and Mars is presented, both from the engineering and scientific point of view, through the analysis of Venus Express and Mars Global Surveyor (MGS) occultations data, highlighting stronger calibrations required for VEX, the extreme, hostile, thick Venus’ atmosphere, and a friendly, thin Mars’ atmosphere. This investigation analyzes Venus Express data recorded by the NASA Deep Space Network in 2014, and the results are compatible to previous studies of Venus atmosphere with VEX between 2006 and 2009.

Analysis of selected Solar events with Mars Express radio occultation data 

2021 ◽  
Author(s):  
Özgür Karatekin ◽  
Ananya Krishnan ◽  
Nayeem Ebrahimkutty ◽  
Greg Henry ◽  
Ahmed El Fadhel ◽  
...  
Keyword(s):  
Radio Occultation ◽  
Mars Express ◽  
Solar Events ◽  
Occultation Data ◽  
Radio Occultation Data

scholarly journals Six years of total ozone column measurements from SCIAMACHY nadir observations

2009 ◽  
Vol 2 (1) ◽  
pp. 87-98 ◽  
Author(s):  
C. Lerot ◽  
M. Van Roozendael ◽  
J. van Geffen ◽  
J. van Gent ◽  
C. Fayt ◽  
...  
Keyword(s):  
Cross Sections ◽  
Total Ozone ◽  
Large Scale ◽  
European Space Agency ◽  
Data Sets ◽  
Data Set ◽  
Ozone Data ◽  
Space Agency ◽  
German Aerospace ◽  
The Impact

Abstract. Total O3 columns have been retrieved from six years of SCIAMACHY nadir UV radiance measurements using SDOAS, an adaptation of the GDOAS algorithm previously developed at BIRA-IASB for the GOME instrument. GDOAS and SDOAS have been implemented by the German Aerospace Center (DLR) in the version 4 of the GOME Data Processor (GDP) and in version 3 of the SCIAMACHY Ground Processor (SGP), respectively. The processors are being run at the DLR processing centre on behalf of the European Space Agency (ESA). We first focus on the description of the SDOAS algorithm with particular attention to the impact of uncertainties on the reference O3 absorption cross-sections. Second, the resulting SCIAMACHY total ozone data set is globally evaluated through large-scale comparisons with results from GOME and OMI as well as with ground-based correlative measurements. The various total ozone data sets are found to agree within 2% on average. However, a negative trend of 0.2–0.4%/year has been identified in the SCIAMACHY O3 columns; this probably originates from instrumental degradation effects that have not yet been fully characterized.

Europe's Path To Mars: The European Space Agency's Mars Express Mission

2011 ◽  
Vol 41 (2) ◽  
pp. 123-178 ◽  
Author(s):  
Arturo Russo
Keyword(s):  
Selection Process ◽  
European Space Agency ◽  
Management Approach ◽  
Mars Exploration ◽  
Mars Express ◽  
The Public ◽  
Science Programme ◽  
Space Agency ◽  
History Of

Mars Express is the first planetary mission accomplished by the European Space Agency (ESA). Launched in early June 2003, the spacecraft entered Mars's orbit on Christmas day of that year, demonstrating the new European commitment to planetary exploration. Following a failed attempt in the mid-1980s, two valid proposals for a European mission to Mars were submitted to ESA's decision-making bodies in the early 1990s, in step with renewed international interest in Mars exploration. Both were rejected, however, in the competitive selection process for the agency's Science Programme. Eventually, the Mars Express proposal emerged during a severe budgetary crisis in the mid-1990s as an exemplar of a “flexible mission” that could reduce project costs and development time. Its successful maneuvering through financial difficulties and conflicting scientific interests was due to the new management approach as well as to the public appeal of Mars exploration. In addition to providing a case study in the functioning of the ESA's Science Programme, the story of Mars Express discussed in this paper provides a case study in the functioning of the European Space Agency's Science Programme and suggests some general considerations on the peculiar position of space research in the general field of the history of science and technology.

A Sporadic Third Layer in the Ionosphere of Mars

Science ◽  
2005 ◽  
Vol 310 (5749) ◽  
pp. 837-839 ◽  
Author(s):  
M. Pätzold ◽  
S. Tellmann ◽  
B. Häusler ◽  
D. Hinson ◽  
R. Schaa ◽  
...  
Keyword(s):  
Electron Density ◽  
Charge Exchange ◽  
Layer Structure ◽  
Electron Densities ◽  
Ionospheric Layer ◽  
Density Profiles ◽  
Mars Express ◽  
Radio Science ◽  
Martian Ionosphere ◽  
Electron Density Profiles

The daytime martian ionosphere has been observed as a two-layer structure with electron densities that peak at altitudes between about 110 and 130 kilometers. The Mars Express Orbiter Radio Science Experiment on the European Mars Express spacecraft observed, in 10 out of 120 electron density profiles, a third ionospheric layer at altitude ranges of 65 to 110 kilometers, where electron densities, on average, peaked at 0.8 × 1010 per cubic meter. Such a layer has been predicted to be permanent and continuous. Its origin has been attributed to ablation of meteors and charge exchange of magnesium and iron. Our observations imply that this layer is present sporadically and locally.

scholarly journals Oblique reflections in the Mars Express MARSIS data set: Stable density structures in the Martian ionosphere

2014 ◽  
Vol 119 (5) ◽  
pp. 3944-3960 ◽  
Author(s):  
D. J. Andrews ◽  
M. André ◽  
H. J Opgenoorth ◽  
N. J. T. Edberg ◽  
C. Diéval ◽  
...  
Keyword(s):  
Data Set ◽  
Mars Express ◽  
Martian Ionosphere

Analysis of solar events with Mars Express radio occultation data

2020 ◽  
Author(s):  
Özgür Karatekin ◽  
Ananya Krishnan ◽  
Julien Drevon ◽  
Ahmed El Fadhel ◽  
Nicolas Bergeot ◽  
...  
Keyword(s):  
Radio Occultation ◽  
Mars Express ◽  
Solar Events ◽  
Occultation Data ◽  
Radio Occultation Data

scholarly journals Gaia Data Release 2

2018 ◽  
Vol 616 ◽  
pp. A13 ◽  
Author(s):  
◽  
F. Spoto ◽  
P. Tanga ◽  
F. Mignard ◽  
J. Berthier ◽  
...  
Keyword(s):  
Solar System ◽  
A Priori ◽  
European Space Agency ◽  
Dramatic Improvement ◽  
Individual Values ◽  
Data Set ◽  
Position Information ◽  
Additional Information ◽  
Space Agency ◽  
Data Release

Context. The Gaia spacecraft of the European Space Agency (ESA) has been securing observations of solar system objects (SSOs) since the beginning of its operations. Data Release 2 (DR2) contains the observations of a selected sample of 14,099 SSOs. These asteroids have been already identified and have been numbered by the Minor Planet Center repository. Positions are provided for each Gaia observation at CCD level. As additional information, complementary to astrometry, the apparent brightness of SSOs in the unfiltered G band is also provided for selected observations. Aims. We explain the processing of SSO data, and describe the criteria we used to select the sample published in Gaia DR2. We then explore the data set to assess its quality. Methods. To exploit the main data product for the solar system in Gaia DR2, which is the epoch astrometry of asteroids, it is necessary to take into account the unusual properties of the uncertainty, as the position information is nearly one-dimensional. When this aspect is handled appropriately, an orbit fit can be obtained with post-fit residuals that are overall consistent with the a-priori error model that was used to define individual values of the astrometric uncertainty. The role of both random and systematic errors is described. The distribution of residuals allowed us to identify possible contaminants in the data set (such as stars). Photometry in the G band was compared to computed values from reference asteroid shapes and to the flux registered at the corresponding epochs by the red and blue photometers (RP and BP). Results. The overall astrometric performance is close to the expectations, with an optimal range of brightness G ~ 12 − 17. In this range, the typical transit-level accuracy is well below 1 mas. For fainter asteroids, the growing photon noise deteriorates the performance. Asteroids brighter than G ~ 12 are affected by a lower performance of the processing of their signals. The dramatic improvement brought by Gaia DR2 astrometry of SSOs is demonstrated by comparisons to the archive data and by preliminary tests on the detection of subtle non-gravitational effects.

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