Results 71 to 80 of about 1,149 (246)

An Unbalanced QPSK-Based Integrated Communication-Ranging System for Distributed Spacecraft Networking

Sensors, 2020
The spacecraft tracking telemetering and command (TT&C) system plays an essential role in celestial and terrestrial networks, requiring relative ranging and communication, particularly in satellite formation flying networks and distributed spacecraft ...
Na Zhao, Qing Chang, Hao Wang, Zhibo Zhang   +3 more
doaj   +1 more source

An eye on long‐duration spaceflight: Controversies, countermeasures and challenges

Experimental Physiology, EarlyView.
Abstract Space flight‐associated neuroocular syndrome (SANS) is a consequence of long‐duration space flight and is detected in two‐thirds of astronauts. In‐flight, this can cause a change in the refraction of the eyes, requiring graded hypermetropic ‘superfocus adjustable’ glasses, optic nerve head oedema and choroidal folds.
Vincent Wing Sum Ng, Susan Patricia Mollan   +1 more
wiley   +1 more source

Adaptive Terminal Sliding Mode Control of Electromagnetic Spacecraft Formation Flying in Near-Earth Orbits

Advances in Mechanical Engineering, 2014
An adaptive terminal sliding mode control for six-degree-of-freedom electromagnetic spacecraft formation flying (EMFF) in near-Earth orbits is presented.
Jingrui Zhang, Changqin Yuan, Dongmei Jiang, Dawei Jin   +3 more
doaj   +1 more source

The Influence of J2 on Formation Flying of Micro-Satellites in Low Near Equatorial Orbits

Journal of Advances in Information Technology, 2014
Taking into considerations the effect of the Earth’s oblateness parameters, particularly J2, the present work assess such influence on the formation flight of micro satellites in near equatorial low orbits. The modified Clohessy-Wiltshire equations
Harijono Djojodihardjo
doaj   +1 more source

Isometric training at longer muscle–tendon complex lengths: A potential countermeasure to impaired neuro‐muscle–tendon function during space travel

Experimental Physiology, EarlyView.
Abstract Manned space exploration to distant destinations, including Mars, continues to be an aspiration of humankind. Space travel does, however, present many challenges to the body, amongst which adaptation to microgravity is perhaps the largest. For instance, both short and long manned spaceflight missions have shown substantial deleterious effects ...
Gerard McMahon, Andy Sanderson, Hans Degens   +2 more
wiley   +1 more source

Consensus SE(3)-Constrained Extended Kalman Filter for Close Proximity Orbital Relative Pose Estimation

Aerospace
In this paper, a recently proposed SE(3)-constrained extended Kalman filter (EKF) is extended to formulate a strategy for relative orbit estimation in a space-based sensor network. The resulting consensus SE(3)-constrained EKF utilizes space-based sensor
S. Mathavaraj, Eric A. Butcher
doaj   +1 more source

Spaceborne and spaceborn: Physiological aspects of pregnancy and birth during interplanetary flight

Experimental Physiology, EarlyView.
Abstract Crewed interplanetary return missions that are on the planning horizon will take years, more than enough time for initiation and completion of a pregnancy. Pregnancy is viewed as a sequence of processes – fertilization, blastocyst formation, implantation, gastrulation, placentation, organogenesis, gross morphogenesis, birth and neonatal ...
Arun V. Holden
wiley   +1 more source

Reduced attitude synchronization of rigid spacecraft with guaranteed performance

Franklin Open
This paper addresses the problem of reduced attitude synchronization, specifically focusing on the coordination of pointing directions between two spacecraft modeled as rigid bodies.
Geethu I., Rakesh R. Warier
doaj   +1 more source

Low magnetic disturbance analysis and testing of a novel proof mass type for gravitational reference sensor system

Advances in Mechanical Engineering, 2019
The proof mass used for gravitational-wave or Earth-gravity-field detection is usually comprised of materials such as gold–platinum alloys, which have a high density and low magnetic susceptibility, in order to reduce the magnetic disturbance produced by
Zeyang Zhao, Zhaokui Wang, Yulin Zhang
doaj   +1 more source

Dynamics Modeling of Spacecraft Formation Flying and Evaluating the Models Accuracy under the Effects of Relative Distance, Eccentricity and Earth Gravitational Perturbation [PDF]

فصلنامه علوم و فناوری فضایی, 2012
Relative motion of satellites in a formation can be studied in several forms of dynamics models. In this paper, some of the most applicable models each implying particular assumptions, constraints and specifications are described in Cartesian and orbital
M. Navabi, M. Barati
doaj