606 research outputs found
Outer planet probe cost estimates: First impressions
An examination was made of early estimates of outer planetary atmospheric probe cost by comparing the estimates with past planetary projects. Of particular interest is identification of project elements which are likely cost drivers for future probe missions. Data are divided into two parts: first, the description of a cost model developed by SAI for the Planetary Programs Office of NASA, and second, use of this model and its data base to evaluate estimates of probe costs. Several observations are offered in conclusion regarding the credibility of current estimates and specific areas of the outer planet probe concept most vulnerable to cost escalation
A survey of multiple missions using gravity-assisted trajectories
Launch opportunities and advantages of gravity- assisted multiple missions to specific solar system target
Asteroid mission alternatives
The options for asteroid missions are evaluated within the constraints of existing or planned launch vehicles and low-thrust propulsion systems. A wide variety of missions is possible, including flyby, rendezvous, and even sample return. The multi-asteroid rendezvous concept requires an ion drive low-thrust propulsion system of the type being developed for a comet rendezvous. It is indicated that there are plentiful opportunities for such missions to visit four asteroids with stay times of 60-90 days each and with transit times between rendezvous of the order of a year
Hair-brane Ideas on the Horizon
We continue an examination of the microstate geometries program begun in
arXiv:1409.6017, focussing on the role of branes that wrap the cycles which
degenerate when a throat in the geometry deepens and a horizon forms. An
associated quiver quantum mechanical model of minimally wrapped branes exhibits
a non-negligible fraction of the gravitational entropy, which scales correctly
as a function of the charges. The results suggest a picture of AdS_3/CFT_2
duality wherein the long string that accounts for BTZ black hole entropy in the
CFT description, can also be seen to inhabit the horizon of BPS black holes on
the gravity side.Comment: 50 pages, 4 figures. v2: minor corrections, reference adde
Trajectory and propulsion characteristics of comet rendezvous opportunities
Trajectory and propulsion characteristics of spacecraft rendezvous mission opportunities to comets during 1975 to 199
Pioneer Mars 1979 mission options
A preliminary investigation of lower cost Mars missions which perform useful exploration objectives after the Viking/75 mission was conducted. As a study guideline, it was assumed that significant cost savings would be realized by utilizing Pioneer hardware currently being developed for a pair of 1978 Venus missions. This in turn led to the additional constraint of a 1979 launch with the Atlas/Centaur launch vehicle which has been designated for the Pioneer Venus missions. Two concepts, using an orbiter bus platform, were identified which have both good science potential and mission simplicity indicative of lower cost. These are: (1) an aeronomy/geology orbiter, and (2) a remote sensing orbiter with a number of deployable surface penetrometers
The accessible regions presentation of gravity-assisted trajectories using Jupiter
Accessibility of solar system regions to earth launched spacecraft using Jupiter gravity- assisted trajectorie
Orbital imagery for planetary exploration. Volume 3 - Orbit selection and definition
Orbital imagery for planetary exploration - orbital selections for Mars, Venus, Mercury, and Jupite
Ocean acidification does not alter grazing in the calanoid copepods Calanus finmarchicus and Calanus glacialis
It is currently under debate whether organisms that regulate their acid–base status under environmental hypercapnia demand additional energy. This could impair animal fitness, but might be compensated for via increased ingestion rates when food is available. No data are yet available for dominant Calanus spp. from boreal and Arctic waters. To fill this gap, we incubated Calanus glacialis at 390, 1120, and 3000 µatm for 16 d with Thalassiosira weissflogii (diatom) as food source on-board RV Polarstern in Fram Strait in 2012. Every 4 d copepods were subsampled from all CO2 treatments and clearance and ingestion rates were determined. During the SOPRAN mesocosm experiment in Bergen, Norway, 2011, we weekly collected Calanus finmarchicus from mesocosms initially adjusted to 390 and 3000 µatm CO2 and measured grazing at low and high pCO2. In addition, copepods were deep frozen for body mass analyses. Elevated pCO2 did not directly affect grazing activities and body mass, suggesting that the copepods did not have additional energy demands for coping with acidification, neither during long-term exposure nor after immediate changes in pCO2. Shifts in seawater pH thus do not seem to challenge these copepod species
2016 Student Compostition Concert
The School of Music\u27s talented student composers present a concert featuring the students\u27 original composed works performed by a wide variety of ensembles and instrumentation.https://digitalcommons.kennesaw.edu/musicprograms/1032/thumbnail.jp
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