Results 31 to 40 of about 4,818 (307)
Toward Accurate Physics‐Based Specifications of Neutral Density Using GNSS‐Enabled Small Satellites
Space Weather, 2021 Satellite‐atmosphere interactions cause large uncertainties in low‐Earth orbit determination and prediction. Thus, knowledge of and the ability to predict the space environment, most notably thermospheric mass density, are essential for operating ...
Eric K. Sutton +6 more
doaj +1 more source
Minimum thrust levels for spinning drag-free satellites [PDF]
Automatica, 1975 Abstract A drag-free satellite, which contains an internal unsupported proof mass, is shielded form external forces such as solar pressure. Thrustors force via a linear control law with a deadband - the satellite to follow the proof mass and hence the satellite follows an almost purely gravitational orbit.
Geert Jan Olsder, J. David Powell
openaire +1 more source
Comparison of a Neutral Density Model With the SET HASDM Density Database
Space Weather, 2021 The EXospheric TEMperatures on a PoLyhedrAl gRid (EXTEMPLAR) method predicts the neutral densities in the thermosphere. The performance of this model has been evaluated through a comparison with the Air Force High Accuracy Satellite Drag Model (HASDM ...
Daniel R. Weimer +5 more
doaj +1 more source
Strategies for in-orbit calibration of drag-free control systems
, 2008 Drag-Free Satellites (DFS) are a class of scientific satellite missions designed for research on fundamental physics as well as geodesy. They consist, basically, of a small inner satellite (test mass) located in a cavity inside a larger satellite, the ...
Leite Filho, Waldemar Castro +2 more
core +1 more source
Unexpected space weather causing the reentry of 38 Starlink satellites in February 2022
Journal of Space Weather and Space Climate, 2022 The accidental reentry of 38 Starlink satellites occurred in early February 2022, associated with the occurrence of moderate magnetic storms. A poorly understood structure of Coronal Mass Ejections (CMEs) caused the magnetic storms at unexpected timing ...
Kataoka Ryuho +6 more
doaj +1 more source
Drag of suction cup tags on swimming animals : modeling and measurement [PDF]
, 2014 This work was supported by NOPP with NSF funds through ONR Grant N00014-11-1-0113. MJ was supported by NOPP and the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland).
Johnson, Mark +5 more
core +1 more source
Test Mass Capture Control for Drag-Free Satellite Based on State-Dependent Riccati Equation Method
ActuatorsThe drag-free satellite plays an important role in the space-based gravitational wave observatory. The capture control of test mass after release is a crucial technology that can affect the success of the mission.
Yingjie Chen +4 more
doaj +1 more source
Advanced Functional Materials, EarlyView.Two nitrogen‐doped 2D conjugated metal‐organic frameworks (2D c‐MOFs, namely Cu‐Nx‐OHBA, x = 2 or 4) are synthesized, featuring precise nitrogen incorporation via rational ligand design. The Cu‐Nx‐OHBA 2D c‐MOFs are largely tailorable by varying skeletal nitrogen density, with respect to electrical conductivity, Li‐storage capacitance, and Li‐transport
Xiangyu Li +7 more
wiley +1 more source
Data‐Driven Satellite Drag Modeling Without Dynamic Knowledge of the Atmosphere
Space WeatherIncreasing congestion in low Earth orbit (LEO) from new satellite deployments and a growing debris population has made accurate orbital trajectory prediction essential for anticipating and avoiding potential collisions on a regular basis.
William E. Parker, Richard Linares
doaj +1 more source
Designed Lewis Acid–Base Passivation for High Performance Perovskite Solar Cells
Advanced Functional Materials, EarlyView.ABSTRACT Silicon's high cost and long energy payback time remain major barriers to the global expansion of solar power. In contrast, metal–halide perovskites offer abundant, solution‐processable absorbers, and have achieved efficiencies of 25%–30%, positioning them as strong competitors to silicon.
Afna Manaf +4 more
wiley +1 more source