Search results for "Physics::Space Physics"
showing 10 items of 357 documents
"Table 133" of "Studies of QCD at e+ e- centre-of-mass energies between 91-GeV and 209-GeV."
2004
Oblateness distribution at c.m. energy 91.20 GeV.
"Table 135" of "Studies of QCD at e+ e- centre-of-mass energies between 91-GeV and 209-GeV."
2004
Oblateness distribution at c.m. energy 161.00 GeV.
"Table 136" of "Studies of QCD at e+ e- centre-of-mass energies between 91-GeV and 209-GeV."
2004
Oblateness distribution at c.m. energy 172.00 GeV.
"Table 137" of "Studies of QCD at e+ e- centre-of-mass energies between 91-GeV and 209-GeV."
2004
Oblateness distribution at c.m. energy 183.00 GeV.
"Table 139" of "Studies of QCD at e+ e- centre-of-mass energies between 91-GeV and 209-GeV."
2004
Oblateness distribution at c.m. energy 200.00 GeV.
Optimal Starting Conditions for the Rendezvous Maneuver, Part 1: Optimal Control Approach
2008
We consider the three-dimensional rendezvous between two spacecraft: a target spacecraft on a circular orbit around the Earth and a chaser spacecraft initially on some elliptical orbit yet to be determined. The chaser spacecraft has variable mass, limited thrust, and its trajectory is governed by three controls, one determining the thrust magnitude and two determining the thrust direction. We seek the time history of the controls in such a way that the propellant mass required to execute the rendezvous maneuver is minimized. Two cases are considered: (i) time-to-rendezvous free and (ii) time-to-rendezvous given, respectively equivalent to (i) free angular travel and (ii) fixed angular trave…
Optimal Trajectories for Spacecraft Rendezvous
2007
The efficient execution of a rendezvous maneuver is an essential component of various types of space missions. This work describes the formulation and numerical investigation of the thrust function required to minimize the time or fuel required for the terminal phase of the rendezvous of two spacecraft. The particular rendezvous studied concerns a target spacecraft in a circular orbit and a chaser spacecraft with an initial separation distance and separation velocity in all three dimensions. First, the time-optimal rendezvous is investigated followed by the fuel-optimal rendezvous for three values of the max-thrust acceleration via the sequential gradient-restoration algorithm. Then, the ti…
Influence of the Electromagnetic, G-Jitter or Thermocapillary Forces on the Stability of the Stationary Buoyancy Convection
1992
Microgravity conditions seem to be very useful for crystal growth processes. Reduced gravitational force strongly weakens the buoyancy convection, so the convective oscillations in the melt become impossible [1]. This is the main reason of numerous attempts to obtain monocrystal materials with homogeneous internal structure in microgravity. On the other hand for non-isothermal fluid in microgravity conditions other driving forces become more significant than on the Earth. The main of them are thermocapillarity and g-jitter. The thermocapillary forces exist on the non-uniformly heated free liquid surfaces and cause motion of the fluid. The g-jitter appears in space unavoidably because of the…
Evidence of small-scale magnetic concentrations dragged by vortex motion of solar photospheric plasma
2010
Vortex-type motions have been measured by tracking bright points in high-resolution observations of the solar photosphere. These small-scale motions are thought to be determinant in the evolution of magnetic footpoints and their interaction with plasma and therefore likely to play a role in heating the upper solar atmosphere by twisting magnetic flux tubes. We report the observation of magnetic concentrations being dragged towards the center of a convective vortex motion in the solar photosphere from high-resolution ground-based and space-borne data. We describe this event by analyzing a series of images at different solar atmospheric layers. By computing horizontal proper motions, we detec…
Theoretical absorption spectrum of the Ar–CO van der Waals complex
2003
The three-dimensional intermolecular electric dipole moment surface of Ar–CO is calculated at the coupled cluster singles and doubles level of theory with the aug-cc-pVTZ basis set extended with a 3s3p2d1f1g set of midbond functions. Using the rovibrational energies and wave functions of our recent study [J. Chem. Phys. 117, 6562 (2002)], temperature-dependent spectral intensities are evaluated and compared to available experimental data. Based on the theoretical spectrum, alternative assignments of the experimentally observed lines in the fundamental band of CO around 2160 and 2166 cm−1 are suggested. Thomas.Bondo@uv.es