Results 91 to 100 of about 1,938 (262)

GPS-Based Precision Baseline Reconstruction for the TanDEM-X SAR-Formation [PDF]

, 2007
The TanDEM-X formation employs two separate spacecraft to collect interferometric Synthetic Aperature Radar (SAR) measurements over baselines of about 1 km.
van Barneveld, Luuk, Montenbruck, Oliver, Visser, Pieter, Yoon, Yoke   +3 more
core  

The role of composition in the spectral evolution of carbonaceous asteroids as informed by Bennu sample return

Meteoritics &Planetary Science, EarlyView.
Abstract Near‐Earth rubble‐pile asteroids Bennu and Ryugu are part of the carbonaceous taxonomic complex (C‐complex), and samples returned from both bodies resemble the most aqueously altered carbonaceous chondrites. However, telescopic and spacecraft visible–near infrared (VIS–NIR) reflectance spectra of Ryugu exhibit a red (positive) spectral slope ...
Ralph E. Milliken, Takahiro Hiroi, Victoria E. Hamilton, Cody D. Schultz, Ed A. Cloutis, Hannah H. Kaplan, Melissa K. Kontogiannis, Nathalia Vega‐Santiago, Dani N. DellaGiustina, Harold C. Connolly Jr., Dante S. Lauretta   +10 more
wiley   +1 more source

Satellite Formation Flying Determination with Low-Cost GNSS Receivers Raw Data

Remote Sensing
Low-cost missions are ideal for applications that require spacecraft formation flying. The use of GNSS signals provides an economical solution to determine the orbital status of the formation.
David Forero, Segundo Esteban, Oscar R. Polo   +2 more
doaj   +1 more source

Deflecting small asteroids using laser ablation : Deep space navigation and asteroid orbit control for LightTouch2 Mission [PDF]

, 2013
This paper presents a low-cost, low mass, mission design to successfully intercept and deflect a small and faint, 4 m in diameter asteroid. Intended to be launched after 2025, the laser-ablating mission, LightTouch2 will be used to deflect the orbit of ...
Daniel Garci Yarnoz, Sanchez Cuartielles, Joan-Pau, Vasile, Massimiliano, Branco, Joao, Massimiliano L. Vasile, Garcia Yarnoz, Daniel, Vetrisano, Massimo, Massimo Vetrisano, João Branco, Joan Pau Sanchez Cuartielles   +9 more
core   +1 more source

Nanoscale space weathering features in mature lunar soil revealed by TEM and APT

Meteoritics &Planetary Science, EarlyView.
Abstract Space weathering significantly alters the optical, chemical, and structural properties of lunar regolith at micro‐ and nanoscales; yet detailed nanoscale variability within individual soils remains underexplored. Here we apply transmission electron microscopy (TEM) and atom probe tomography to four mineral grains (olivine, ilmenite, and two ...
Jennika Greer, Alexander M. Kling, Luke Daly, Dieter Isheim, David N. Seidman, Michelle S. Thompson, Philipp R. Heck   +6 more
wiley   +1 more source

Microstructural evidence for multiple generations of sulfide precipitation and impact‐induced thermal alteration under acidic conditions on Asteroid Ryugu

Meteoritics &Planetary Science, EarlyView.
Abstract Here we report on the microstructure and chemistry of sulfide minerals returned from asteroid (162173) Ryugu. We identify a unique sulfide population in particle A0016 composed of violarite (FeNi2S4), pyrite (FeS2), chalcopyrite (CuFeS2), pyrrhotite (Fe1‐xS), and pentlandite ([Fe,Ni]9S8).
M. C. Benner, B. S. Prince, D. L. Schrader, T. J. Zega   +3 more
wiley   +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

Evaluating interferometric baseline performances in a close formation flight by using relative GRACE GPS navigation solutions [PDF]

, 2006
In this paper the impact of relative position errors on the interferometric baseline performance of multistatic Synthetic Aperture Radar (SAR) satellites flying in a close formation is analyzed and assessed.
Kohlhase, Andreas, Kroes, Remko, D'Amico, Simone   +2 more
core