Search Publications
Aggregate particles in the plumes of Enceladus
Ingersoll, Andrew P.; Zhang, Xi; Gao, Peter +1 more
Estimates of the total particulate mass of the plumes of Enceladus are important to constrain theories of particle formation and transport at the surface and interior of the satellite. We revisit the calculations of Ingersoll and Ewald (Ingersoll, A.P., Ewald, S.P. [2011]. Icarus 216(2), 492-506), who estimated the particulate mass of the Enceladu…
Automated localisation of Mars rovers using co-registered HiRISE-CTX-HRSC orthorectified images and wide baseline Navcam orthorectified mosaics
Tao, Yu; Muller, Jan-Peter; Poole, William
We present a wide range of research results in the area of orbit-to-orbit and orbit-to-ground data fusion, achieved within the EU-FP7 PRoVisG project and EU-FP7 PRoViDE project. We focus on examples from three Mars rover missions, i.e. MER-A/B and MSL, to provide examples of a new fully automated offline method for rover localisation. We start by …
Characterization of artifacts introduced by the empirical volcano-scan atmospheric correction commonly applied to CRISM and OMEGA near-infrared spectra
Arvidson, R. E.; Morris, R. V.; Mustard, J. F. +8 more
The empirical 'volcano-scan' atmospheric correction is widely applied to martian near infrared CRISM and OMEGA spectra between ∼1000 and ∼2600 nm to remove prominent atmospheric gas absorptions with minimal computational investment. This correction method employs division by a scaled empirically-derived atmospheric transmission spectrum that is ge…
DSMC simulation of Europa water vapor plumes
Trafton, L. M.; Berg, J. J.; Goldstein, D. B. +1 more
A computational investigation of the physics of water vapor plumes on Europa was performed with a focus on characteristics relevant to observation and spacecraft mission operations. The direct simulation Monte Carlo (DSMC) method was used to model the plume expansion assuming a supersonic vent source. The structure of the plume was determined, inc…
Stability within Jupiter's polar auroral 'Swirl region' over moderate timescales
Clarke, John T.; O'Donoghue, James; Connerney, John E. P. +7 more
Jupiter's Swirl region, poleward of the main auroral emission, has been characterised in previous observations as having highly variable auroral emission, changing dramatically across the region on a two-minute timescale, the typical integration time for UV images. This variability has made comparisons with H3+ emission diffi…
Treatment of non-sparse cratering in planetary surface dating
Michael, G. G.; Kneissl, T.; Schmedemann, N.
We here propose a new technique to derive crater size-frequency distributions (CSFDs) from non-sparsely cratered surfaces, by accounting for the loss of craters due to subsequent crater/ejecta coverage. This approach, which we refer to as the buffered non-sparseness correction (BNSC), relates each crater to a measurement area found by excluding re…
Enhanced erosion rates on Mars during Amazonian glaciation
Head, James W.; Fassett, Caleb I.; Levy, Joseph S.
Observations of Mars from the surface and from orbit suggest that erosion rates over the last ∼3 Gyr (the Amazonian) have been as slow as 10-5 m/Myr and have been dominated by aeolian processes, while ancient (Noachian) erosion rates may have been orders of magnitude higher due to impact bombardment and fluvial activity. Amazonian-aged …
How Janus' orbital swap affects the edge of Saturn's A ring?
Nicholson, Philip D.; French, Richard G.; Hedman, Matthew M. +6 more
We present a study of the behavior of Saturn's A ring outer edge, using images and occultation data obtained by the Cassini spacecraft over a period of 8 years from 2006 to 2014. More than 5000 images and 170 occultations of the A ring outer edge are analyzed. Our fits confirm the expected response to the Janus 7:6 Inner Lindblad resonance (ILR) b…
Saturn kilometric radiation intensities during the Saturn auroral campaign of 2013
Gurnett, D. A.; Dougherty, M. K.; Hospodarsky, G. B. +9 more
The Saturn auroral campaign carried out in the spring of 2013 used multiple Earth-based observations, remote-sensing observations from Cassini, and in situ-observations from Cassini to further our understanding of auroras at Saturn. Most of the remote sensing and Earth-based measurements are, by nature, not continuous. And, even the in situ measur…
Characterizing the particle size distribution of Saturn's A ring with Cassini UVIS occultation data
Colwell, Joshua E.; Esposito, Larry W.; Becker, Tracy M. +1 more
Stellar occultation data from Cassini's Ultraviolet Imaging Spectrograph (UVIS) have revealed diffraction spikes near sharp edges in Saturn's rings. The UVIS High Speed Photometer (HSP) observes these spikes as signals at ring edges that surpass measurements of the unocculted stellar signal. In Saturn's A ring, diffracted light can augment the dir…