Browsing Peer Reviewed by Title
Now showing items 4-23 of 24
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Characterization of a semidiurnal eastward-propagating tide at high northern latitudes with Mars Global Surveyor electron density profiles
(American Geophysical Union, 2007-08-03)Apparent phase velocities of zonal structure, estimated from Mars Global Surveyor (MGS) electron density profiles, are used to identify and characterize SE1, the semidiurnal eastward-propagating tide with zonal wave number ... -
Communication satellite power amplifiers: current and future SSPA and TWTA technologies
(Wiley, 2016-04)This study captures the state of current satellite transponder technology, specifically, solid-state power amplifiers (SSPAs) and traveling wave tube amplifiers (TWTAs), and describes expected future advances, including ... -
Effect of Longitude-Dependent Cloud Coverage on Exoplanet Visible Wavelength Reflected-Light Phase Curves
(IOP Publishing, 2015-05-10)We use a planetary albedo model to investigate variations in visible wavelength phase curves of exoplanets. Thermal and cloud properties for these exoplanets are derived using one-dimensional radiative-convective and cloud ... -
Exoplanet Albedo Spectra and Colors as a Function of Planet Phase, Separation, and Metallicity
(The Astrophysical Journal, 2010-11-20)First generation space-based optical coronagraphic telescopes will obtain images of cool gas- and ice-giant exoplanets around nearby stars. Exoplanets lying at planet-star separations larger than about 1 AU—where an exoplanet ... -
Implementation and validation of a CubeSat laser transmitter
(SPIE, 2016)The paper presents implementation and validation results for a CubeSat-scale laser transmitter. The master oscillator power amplifier (MOPA) design produces a 1550 nm, 200mW average power optical signal through the use of ... -
Interplanetary space weather effects on Lunar Reconnaissance Orbiter avalanche photodiode performance.
(Space Weather: The International Journal of Research & Applications, 2016)Space weather is a major concern for radiation-sensitive space systems, particularly for interplanetary missions, which operate outside of the protection of Earth's magnetic field. We examine and quantify the effects of ... -
Interpolation Method for Update with Out-of-Sequence Measurements: The Augmented Fixed-Lag Smoother
(American Institute of Aeronautics and Astronautics, 2016-11)In this study, the authors propose a novel method to handle OOSMs in Kalman filtering. The proposed method, called the augmented fixed-lag smoother (AFLS), is based on the fixed-lag smoother (FLS) formulation, which has ... -
Laser-Guide-Star Satellite for Ground-Based Adaptive Optics Imaging of Geosynchronous Satellites
(Journal of Spacecraft & Rockets, 2017-05)In this study, the feasibility and utility of using a maneuverable nanosatellite laser guide star from a geostationary equatorial orbit have been assessed to enable ground-based, adaptive optics imaging of geosynchronous ... -
Mars atmospheric CO2 condensation above the north and south poles as revealed by radio occultation, climate sounder, and laser ranging observations
(Journal Of Geophysical Research-Planets, 2012-07-10)We study the condensation of CO2 in Mars' atmosphere using temperature profiles retrieved from radio occultation measurements from Mars Global Surveyor (MGS) as well as the climate sounding instrument onboard the Mars ... -
Physical characteristics and occurrence rates of meteoric plasma layers detected in the Martian ionosphere by the Mars Global Surveyor Radio Science Experiment
(American Geophysical Union, 2008-12-30)Low-altitude plasma layers are present in 71 of 5600 electron density profiles from the Martian ionosphere obtained by the Mars Global Surveyor Radio Science experiment. These layers are produced by the ablation of meteoroids ... -
Planetary Imaging Concept Testbed Using a Recoverable Experiment-Coronagraph (PICTURE C)
(SPIE, 2015)An exoplanet mission based on a high-altitude balloon is a next logical step in humanity's quest to explore Earthlike planets in Earthlike orbits orbiting Sunlike stars. The mission described here is capable of spectrally ... -
Quantifying the average and the likelihood of increases in space weather indices and in situ measurements during Solar Cycles 20–23
(International Journal of Space Science and Engineering, 2013-01)It is known that space weather harshly affects spacecraft performance, yet spacecraft operations and understanding the cause of anomalies can be challenging due to the complexity of environmental metrics. In this work, we ... -
Radio science measurements of atmospheric refractivity with Mars Global Surveyor
(American Geophysical Union, 2006-05-20)Radio occultation experiments with Mars Global Surveyor measure the refractive index of the Martian atmosphere from the surface to ~250 km in geopotential height. Refractivity is proportional to neutral density at low ... -
Radiometer Calibration Using Colocated GPS Radio Occultation Measurements
(Institute of Electrical and Electronics Engineers, 2014-10)We present a new high-fidelity method of calibrating a cross-track scanning microwave radiometer using Global Positioning System (GPS) radio occultation (GPSRO) measurements. The radiometer and GPSRO receiver periodically ... -
Response of geostationary communications satellite solid-state power amplifiers to high-energy electron fluence
(AGU Space Weather, 2015-05-25)The key components in communications satellite payloads are the high-power amplifiers that amplify the received signal so that it can be accurately transmitted to the intended end user. In this study, we examine 26 amplifier ... -
Response of geostationary communications satellite solid-state power amplifiers to high-energy electron fluence.
(American Geophysical Union, 2015-05)The key components in communications satellite payloads are the high-power amplifiers that amplify the received signal so that it can be accurately transmitted to the intended end user. In this study, we examine 26 amplifier ... -
Space weather radiation effects on geostationary satellite solid-state power amplifiers
(American Geophysical Union, 2013-08)In order to understand and mitigate the effects of space weather on the performance of geostationary (GEO) communications satellites, we analyze 16 years of archived telemetry data from Inmarsat, the UK-based telecommunications ... -
SPICES: spectro-polarimetric imaging and characterization of exoplanetary systems.
(Experimental Astronomy, 2012-10)SPICES (Spectro-Polarimetric Imaging and Characterization of Exoplanetary Systems) is a five-year M-class mission proposed to ESA Cosmic Vision. Its purpose is to image and characterize long-period extrasolar planets and ... -
Telemetry Fault-Detection Algorithms: Applications for Spacecraft Monitoring and Space Environment Sensing
(2018-05-19)Algorithms have been developed that identify unusual behavior in satellite health telemetry. Telemetry from solid-state power amplifiers and amplifier thermistors from 32 geostationary Earth orbit communications satellites ... -
Trapped photoelectrons during spacecraft charging in sunlight
(Institute of Electrical and Electronics Engineers, 2015-09)For a dielectric spacecraft charging in sunlight, the potentials are different on the sunlit and dark sides. Differential charging of spacecraft surfaces can trap low-energy electrons by means of potential wells and barriers. ...