scholarly journals A New Method Based on a Multilayer Perceptron Network to Determine In-Orbit Satellite Attitude for Spacecrafts without Active ADCS Like UVSQ-SAT

2021 ◽  
Vol 13 (6) ◽  
pp. 1185
Author(s):  
Adrien Finance ◽  
Mustapha Meftah ◽  
Christophe Dufour ◽  
Thomas Boutéraon ◽  
Slimane Bekki ◽  
...  
Keyword(s):  
Climate Change ◽  
Deep Learning ◽  
Learning System ◽  
New Method ◽  
Radiation Budget ◽  
The Sun ◽  
Radiative Fluxes ◽  
Satellite Attitude ◽  
The Earth ◽  
Radiation Measurements

Climate change is largely determined by the radiation budget imbalance at the Top Of the Atmosphere (TOA), which is generated by the increasing concentrations of greenhouse gases (GHGs). As a result, the Earth Energy Imbalance (EEI) is considered as an Essential Climate Variable (ECV) that has to be monitored continuously from space. However, accurate TOA radiation measurements remain very challenging. Ideally, EEI monitoring should be performed with a constellation of satellites in order to resolve as much as possible spatio-temporal fluctuations in EEI which contain important information on the underlying mechanisms driving climate change. The monitoring of EEI and its components (incoming solar, reflected solar, and terrestrial infrared fluxes) is the main objective of the UVSQ-SAT pathfinder nanosatellite, the first of its kind in the construction of a future constellation. UVSQ-SAT does not have an active determination system of its orientation with respect to the Sun and the Earth (i.e., the so-called attitude), a prerequisite in the calculation of EEI from the satellite radiation measurements. We present a new effective method to determine the UVSQ-SAT’s in-orbit attitude using its housekeeping and scientific sensors measurements and a well-established deep learning algorithm. One of the goals is to estimate the satellite attitude with a sufficient accuracy for retrieving the radiative fluxes (incoming solar, reflected solar, terrestrial infrared) on each face of the satellite with an uncertainty of less than ±5 Wm−2 (1σ). This new method can be extended to any other satellites with no active attitude determination or control system. To test the accuracy of the method, a ground-based calibration experiment with different attitudes is performed using the Sun as the radiative flux reference. Based on the deep learning estimation of the satellite ground-based attitude, the uncertainty on the solar flux retrieval is about ±16 Wm−2 (1σ). The quality of the retrieval is mainly limited by test conditions and the number of data samples used in training the deep learning system during the ground-based calibration. The expected increase in the number of training data samples will drastically decrease the uncertainty in the retrieved radiative fluxes. A very similar algorithm will be implemented and used in-orbit for UVSQ-SAT.

scholarly journals Editorial for Special Issue “Earth Radiation Budget”

2020 ◽  
Vol 12 (20) ◽  
pp. 3379
Author(s):  
Steven Dewitte
Keyword(s):  
Climate Change ◽  
Remote Sensing ◽  
Radiation Budget ◽  
Climate Data ◽  
Special Issue ◽  
The Earth ◽  
Earth Radiation Budget ◽  
Term Monitoring ◽  
Earth Radiation

The Earth Radiation Budget (ERB) at the top of the atmosphere describes how the Earth gains energy from the Sun and loses energy to space through the reflection of solar radiation and the emission of thermal radiation. The ERB is measured from space with dedicated remote sensing instruments. Its long-term monitoring is of fundamental importance for understanding climate change. This Special Issue contains contributions focusing on ERB remote sensing instruments for either (1) the establishment of past and current ERB Climate Data Records (CDRs), (2) insights in climate change gained from the analysis of ERB CDRs, and 3) the outlook for continued or improved future ERB monitoring.

scholarly journals The Carbon Dioxide Removal Model Intercomparison Project (CDR-MIP): Rationale and experimental design

2017 ◽  
Author(s):  
David P. Keller ◽  
Andrew Lenton ◽  
Vivian Scott ◽  
Naomi E. Vaughan ◽  
Nico Bauer ◽  
...  
Keyword(s):  
Climate Change ◽  
Carbon Dioxide ◽  
Carbon Dioxide Removal ◽  
Radiation Budget ◽  
Earth System ◽  
Emission Scenarios ◽  
Model Intercomparison ◽  
The Earth ◽  
Intercomparison Project ◽  
Removal Model

Abstract. The recent IPCC reports state that continued anthropogenic greenhouse gas emissions are changing the climate threatening "severe, pervasive and irreversible" impacts. Slow progress in emissions reduction to mitigate climate change is resulting in increased attention on what is called Geoengineering, Climate Engineering, or Climate Intervention – deliberate interventions to counter climate change that seek to either modify the Earth's radiation budget or remove greenhouse gases such as CO2 from the atmosphere. When focused on CO2, the latter of these categories is called Carbon Dioxide Removal (CDR). The majority of future emission scenarios that stay well below 2 °C, and nearly all emission scenarios that do not exceed 1.5 °C warming by the year 2100, require some form of CDR. At present, there is little consensus on the impacts and efficacy of the different types of proposed CDR. To address this need the Carbon Dioxide Removal Model Intercomparison Project (or CDR-MIP) was initiated. This project brings together models of the Earth system in a common framework to explore the potential, impacts, and challenges of CDR. Here, we describe the first set of CDR-MIP experiments that are designed to address questions concerning CDR-induced climate "reversibility", the response of the Earth system to direct atmospheric CO2 removal (direct air capture and storage), and the CDR potential and impacts of afforestation/reforestation, as well as ocean alkalinization.

scholarly journals James Croll, celestial mechanics and climate change

2021 ◽  
pp. 1-7
Author(s):  
Malcolm LONGAIR
Keyword(s):  
Climate Change ◽  
Solar System ◽  
Celestial Mechanics ◽  
Orbital Dynamics ◽  
Milankovitch Cycles ◽  
The Sun ◽  
The Earth ◽  
Planetary Orbits ◽  
Mathematical Techniques ◽  
The Impact

ABSTRACT James Croll was a pioneer in studies of the impact of the slowly changing orbital dynamics of the Earth on climate change. His book Climate and Time in their Geological Relations (1875) was far ahead of its time in seeking correlations between climate change, the occurrence of ice ages and perturbations to the Earth's orbit about the Sun. The astronomical cycles he discovered are now called ‘Milankovitch Cycles’ after the Serbian scientist whose research was first published in the Handbuch der Klimatologie in 1930. The celestial mechanical and astronomical background to Croll's research is the focus of this essay. The development of the understanding of the impact of perturbations of the elliptical planetary orbits by other bodies in the solar system paralleled new mathematical techniques, many of which were developed in association with celestial mechanical problems. The central contributions of many of the major mathematicians of the late 18th and 19th Centuries, including Euler, Lagrange, Laplace and Le Verrier, are highlighted. Although Croll's contributions faded from view for several generations, his pioneering insights have now been demonstrated to have been basically correct.

Seti Space Missions

1997 ◽  
Vol 161 ◽  
pp. 761-776 ◽  
Author(s):  
Claudio Maccone
Keyword(s):  
Electromagnetic Waves ◽  
Space Missions ◽  
Gravitational Lens ◽  
The Sun ◽  
Space Antenna ◽  
Focal Distance ◽  
Large Space ◽  
The Earth ◽  
Space Antennas ◽  
New Space

AbstractSETI from space is currently envisaged in three ways: i) by large space antennas orbiting the Earth that could be used for both VLBI and SETI (VSOP and RadioAstron missions), ii) by a radiotelescope inside the Saha far side Moon crater and an Earth-link antenna on the Mare Smythii near side plain. Such SETIMOON mission would require no astronaut work since a Tether, deployed in Moon orbit until the two antennas landed softly, would also be the cable connecting them. Alternatively, a data relay satellite orbiting the Earth-Moon Lagrangian pointL2would avoid the Earthlink antenna, iii) by a large space antenna put at the foci of the Sun gravitational lens: 1) for electromagnetic waves, the minimal focal distance is 550 Astronomical Units (AU) or 14 times beyond Pluto. One could use the huge radio magnifications of sources aligned to the Sun and spacecraft; 2) for gravitational waves and neutrinos, the focus lies between 22.45 and 29.59 AU (Uranus and Neptune orbits), with a flight time of less than 30 years. Two new space missions, of SETI interest if ET’s use neutrinos for communications, are proposed.

Spots on the Sun and Life on the Earth

2019 ◽  
Vol 15 (1) ◽  
pp. 73-77
Author(s):  
Valentina V. Ukraintseva ◽  
Keyword(s):  
The Sun ◽  
The Earth

Religion in the Age of the Anthropocene

2019 ◽  
Author(s):  
Arianne F. Conty
Keyword(s):  
Social Sciences ◽  
Climate Change ◽  
Natural Sciences ◽  
Human Beings ◽  
Risks And Benefits ◽  
Human Exceptionalism ◽  
The Earth ◽  
Contemporary Christian ◽  
Genesis 1 ◽  
Forms Of Life

Though responses to the Anthropocene have largely come from the natural and social sciences, religious responses to the Anthropocene have also been gaining momentum and many scholars have been calling for a religious response to complement scientific responses to climate change. Yet because Genesis 1:28 does indeed tell human beings to ‘subdue the earth’ monotheistic religions have often been understood as complicit in the human exceptionalism that is thought to have created the conditions for the Anthropocene. In distinction to such Biblical traditions, indigenous animistic cultures have typically respected all forms of life as ‘persons’ and such traditions have thus become a source of inspiration for ecological movements. After discussing contemporary Christian efforts to integrate the natural sciences and the environment into their responses to the Anthropocene, this article will turn to animism and seek to evaluate the risks and benefits that could ensue from a postmodern form of animism that could provide a necessary postsecular response to the Anthropocene.

Much Ado about (Practically) Nothing

2010 ◽  
Author(s):  
David Fisher
Keyword(s):  
Energy Source ◽  
Atomic Nucleus ◽  
The Sun ◽  
Scientific Journals ◽  
Rare Gases ◽  
Important Work ◽  
The Earth ◽  
Wide Range ◽  
Life On Mars ◽  
The Universe

There are eight columns in the Periodic Table. The eighth column is comprised of the rare gases, so-called because they are the rarest elements on earth. They are also called the inert or noble gases because, like nobility, they do no work. They are colorless, odorless, invisible gases which do not react with anything, and were thought to be unimportant until the early 1960s. Starting in that era, David Fisher has spent roughly fifty years doing research on these gases, publishing nearly a hundred papers in the scientific journals, applying them to problems in geophysics and cosmochemistry, and learning how other scientists have utilized them to change our ideas about the universe, the sun, and our own planet. Much Ado about (Practically) Nothing will cover this spectrum of ideas, interspersed with the author's own work which will serve to introduce each gas and the important work others have done with them. The rare gases have participated in a wide range of scientific advances-even revolutions-but no book has ever recorded the entire story. Fisher will range from the intricacies of the atomic nucleus and the tiniest of elementary particles, the neutrino, to the energy source of the stars; from the age of the earth to its future energies; from life on Mars to cancer here on earth. A whole panoply that has never before been told as an entity.

Dombey and Son

2008 ◽  
Author(s):  
Charles Dickens ◽  
Dennis Walder
Keyword(s):  
Family Relationships ◽  
The Sun ◽  
The Novel ◽  
The Earth ◽  
The Future ◽  
Original Illustrations ◽  
The One

Dombey and Son ... Those three words conveyed the one idea of Mr. Dombey's life. The earth was made for Dombey and Son to trade in, and the sun and moon were made to give them light.' The hopes of Mr Dombey for the future of his shipping firm are centred on his delicate son Paul, and Florence, his devoted daughter, is unloved and neglected. When the firm faces ruin, and Dombey's second marriage ends in disaster, only Florence has the strength and humanity to save her father from desolate solitude. This new edition contains Dickens's prefaces, his working plans, and all the original illustrations by ‘Phiz’. The text is that of the definitive Clarendon edition. It has been supplemented by a wide-ranging Introduction, highlighting Dickens's engagement with his times, and the touching exploration of family relationships which give the novel added depth and relevance.

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