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Hladczuk, N.A. (author), van den IJssel, J.A.A. (author), Kodikara, T. (author), Siemes, C. (author), Visser, P.N.A.M. (author)
Uncertainties in radiation pressure modelling play a significant role in the thermospheric density and crosswind observations derived from the GRACE-FO accelerometer, especially during low solar activity. Under such conditions, the radiation pressure acceleration matches the magnitude of the aerodynamic acceleration along the track and...
journal article 2024
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Siemes, C. (author), van den IJssel, J.A.A. (author), Visser, P.N.A.M. (author)
Thermosphere mass density and crosswind can be derived from accelerometer and GNSS tracking data. However, present datasets are often provided without comprehensive uncertainty specifications. We present a newly developed method that propagates measurement noise and errors in the satellite specification, thermosphere models, and radiation flux...
journal article 2024
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Callejon Cantero, M. (author), Pastor-Rodriguez, A. (author), Siemes, C. (author)
The uncertainty on Thermospheric Mass Density (TMD), as derived from atmospheric models, can reach extremely high values. This effect is noteworthy in Low Earth Orbit (LEO), where atmospheric drag is the main perturbing force, as well as the most uncertain. LEO harbours almost 18,000 space objects at the end of 2021, around 60% of the total...
conference paper 2023
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Tobiska, W. Kent (author), Pilinski, Marcin (author), Bruinsma, Sean L. (author), Sutton, Eric (author), Knipp, Delores (author), Mallik, Vishnuu (author), Jagatia, Bhavi (author), Siegers, Mike (author), Siemes, C. (author)
In Low Earth Orbit (LEO), atmospheric drag is the largest contributor to trajectory prediction error. The current thermospheric density model used by the Combined Space Operations Center (CSpOC) in operations is the High Accuracy Satellite Drag Model (HASDM). Since HASDM is not available for use outside of the US Government, satellite operators...
conference paper 2023
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Siemes, C. (author), Borries, Claudia (author), Bruinsma, S. (author), Fernandez-Gomez, I. (author), Hladczuk, N.A. (author), van den IJssel, J.A.A. (author), Kodikara, T. (author), Vielberg, K. (author), Visser, P.N.A.M. (author)
We present new neutral mass density and crosswind observations for the CHAMP, GRACE, and GRACE-FO missions, filling the last gaps in our database of accelerometer-derived thermosphere observations. For consistency, we processed the data over the entire lifetime of these missions, noting that the results for GRACE in 2011- 2017 and GRACE-FO...
journal article 2023
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Zhu, Qingyu (author), Lu, Gang (author), Lei, Jiuhou (author), Deng, Yue (author), Doornbos, E.N. (author), van den IJssel, J.A.A. (author), Siemes, C. (author)
The thermospheric neutral density response to the 7–9 September 2017 storms is investigated based on the Swarm satellite observations and the thermosphere-ionosphere-electrodynamic general circulation model (TIEGCM) simulation. The Swarm data depicted a prominent interhemispheric asymmetry (IHA) in the afternoon sector during the second storm...
journal article 2023
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Park, Jaeheung (author), van den IJssel, J.A.A. (author), Siemes, C. (author)
We statistically investigate fluctuation amplitudes (normalized to the background values) of dayside low-/mid-latitude upper-thermospheric mass density as observed by the Gravity Recovery and Climate Experiment (GRACE) and GRACE-Follow-On (GRACE-FO) spacecraft at ∼500 km altitude between 2002 and 2022. There are three new findings in our...
journal article 2023
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He, Jianhui (author), Astafyeva, Elvira (author), Yue, Xinan (author), Pedatella, Nicholas M. (author), Lin, Dong (author), Fuller-Rowell, Timothy J. (author), Fedrizzi, Mariangel (author), Doornbos, E.N. (author), Siemes, C. (author)
On 3 February 2022, at 18:13 UTC, SpaceX launched and a short time later deployed 49 Starlink satellites at an orbit altitude between 210 and 320 km. The satellites were meant to be further raised to 550 km. However, the deployment took place during the main phase of a moderate geomagnetic storm, and another moderate storm occurred on the...
journal article 2023
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Sarris, Theodore E. (author), Tourgaidis, Stelios (author), Pirnaris, Panagiotis (author), Baloukidis, Dimitris (author), Papadakis, Konstantinos (author), Doornbos, Eelco (author), Siemes, C. (author), Visser, P.N.A.M. (author), van den IJssel, J.A.A. (author)
Daedalus MASE (Mission Assessment through Simulation Exercise) is an open-source package of scientific analysis tools aimed at research in the Lower Thermosphere-Ionosphere (LTI). It was created with the purpose to assess the performance and demonstrate closure of the mission objectives of Daedalus, a mission concept targeting to perform in...
journal article 2023
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Siemes, C. (author), Maddox, Stephen (author), Carraz, Olivier (author), Cross, Trevor (author), George, Steven (author), van den IJssel, J.A.A. (author), Kiss-Toth, Marton (author), Pastena, Massimiliano (author), Visser, P.N.A.M. (author)
Cold Atom technology has undergone rapid development in recent years and has been demonstrated in space in the form of cold atom scientific experiments and technology demonstrators, but has so far not been used as the fundamental sensor technology in a science mission. The European Space Agency therefore funded a 7-month project to define the...
journal article 2022
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Bruinsma, Sean (author), Siemes, C. (author), Emmert, John T. (author), Mlynczak, Martin G. (author)
The quality and distribution in time and space of available atmospheric observations are crucial for the accuracy of semi-empirical thermosphere models. However, datasets can be inconsistent, and their qualities and resolutions are often unequal. The main thermospheric density datasets of this century are briefly described and then compared...
journal article 2022
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Catapano, Filomena (author), Buchert, Stephan (author), Qamili, Enkelejda (author), Nilsson, Thomas (author), Bouffard, Jerome (author), Siemes, C. (author), Coco, Igino (author), D'Amicis, Raffaella (author), Tøffner-Clausen, Lars (author), Trenchi, Lorenzo (author), Holmdahl Olsen, Poul Erik (author), Stromme, Anja (author)
Swarm is the European Space Agency (ESA)'s first Earth observation constellation mission, which was launched in 2013 to study the geomagnetic field and its temporal evolution. Two Langmuir probes aboard each of the three Swarm satellites provide in situ measurements of plasma parameters, which contribute to the study of the ionospheric plasma...
journal article 2022
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Mehta, Piyush M. (author), Paul, Smriti N. (author), Crisp, Nicholas H. (author), Sheridan, Philip L. (author), Siemes, C. (author), March, G. (author), Bruinsma, Sean (author)
Satellite drag modeling remains the largest source of uncertainty affecting space operations in low Earth orbit. The uncertainty stems from inaccurate models for mass density and drag coefficient. Drag coefficient modeling also impacts scientific knowledge on the physics and dynamics of the upper atmosphere through the estimation of high...
journal article 2022
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Plumaris, M.K. (author), Dirkx, D. (author), Siemes, C. (author), Carraz, Olivier (author)
Interplanetary missions have typically relied on Radio Science (RS) to recover gravity fields by detecting their signatures on the spacecraft trajectory. The weak gravitational fields of small bodies, coupled with the prominent influence of confounding accelerations, hinder the efficacy of this method. Meanwhile, quantum sensors based on Cold...
journal article 2022
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Massotti, Luca (author), Siemes, C. (author), March, G. (author), Haagmans, Roger (author), Silvestrin, Pierluigi (author)
ESA’s Next Generation Gravity Mission (NGGM) is a candidate Mission of Opportunity for ESA–NASA cooperation in the frame of the Mass Change and Geosciences International Constellation (MAGIC). The mission aims at enabling long-term monitoring of the temporal variations of Earth’s gravity field at relatively high temporal (down to 3 days) and...
journal article 2021
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March, G. (author), van den IJssel, J.A.A. (author), Siemes, C. (author), Visser, P.N.A.M. (author), Doornbos, Eelco N. (author), Pilinski, Marcin (author)
The satellite acceleration data from the CHAMP, GRACE, GOCE, and Swarm missions provide detailed information on the thermosphere density over the last two decades. Recent work on reducing errors in modelling the spacecraft geometry has greatly reduced scale differences between the thermosphere data sets from these missions. However, residual...
journal article 2021
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Palmroth, Minna (author), Grandin, Maxime (author), Sarris, Theodoros (author), Doornbos, Eelco (author), Tourgaidis, Stelios (author), March, G. (author), Siemes, C. (author), van den IJssel, J.A.A. (author), Visser, P.N.A.M. (author)
<p>The lower-Thermosphere-ionosphere (LTI) system consists of the upper atmosphere and the lower part of the ionosphere and as such comprises a complex system coupled to both the atmosphere below and space above. The atmospheric part of the LTI is dominated by laws of continuum fluid dynamics and chemistry, while the ionosphere is a plasma...
journal article 2021
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Schreiter, Lucas (author), Montenbruck, Oliver (author), Zangerl, Franz (author), Siemes, C. (author), Arnold, Daniel (author), Jäggi, Adrian (author)
Gravity fields derived from GPS tracking of the three Swarm satellites have shown artifacts near the geomagnetic equator, where the carrier phase tracking on the L2 frequency is unable to follow rapid ionospheric path delay changes due to a limited tracking loop bandwidth of only 0.25 Hz in the early years of the mission. Based on the...
journal article 2021
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Jiang, Guoying (author), Xiong, Chao (author), Stolle, Claudia (author), Xu, Jiyao (author), Yuan, Wei (author), Makela, Jonathan J. (author), Harding, Brian J. (author), Kerr, Robert B. (author), March, G. (author), Siemes, C. (author)
The re-estimates of thermospheric winds from the Gravity field and steady-state Ocean Circulation Explorer (GOCE) accelerometer measurements were released in April 2019. In this study, we compared the new-released GOCE crosswind (cross-track wind) data with the horizontal winds measured by four Fabry-Perot interferometers (FPIs) located at...
journal article 2021
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Haagmans, Roger (author), Siemes, C. (author), Massotti, Luca (author), Carraz, Olivier (author), Silvestrin, Pierluigi (author)
The paper addresses the preparatory studies of future ESA mission concepts devoted to improve our understanding of the Earth’s mass change phenomena causing temporal variations in the gravity field, at different temporal and spatial scales, due to ice mass changes of ice sheets and glaciers, continental water cycles, ocean masses dynamics and...
review 2020
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