Measurement of the jettisoned object departure trajectory and velocity vector in the International Space Station (ISS)
reference frame is vitally important for prompt evaluation of the object's imminent orbit. We report on the first
successful application of photogrammetric analysis of the ISS imagery for the prompt computation of the jettisoned
object's position and velocity vectors. As post-EVA analyses examples, we present the Floating Potential Probe (FPP)
and the Russian "Orlan" Space Suit jettisons, as well as the
near-real-time (provided in several hours after the separation)
computations of the Video Stanchion Support Assembly Flight Support Assembly (VSSA-FSA) and Early Ammonia
Servicer (EAS) jettisons during the US astronauts space-walk. Standard close-range photogrammetry analysis was used
during this EVA to analyze two on-board camera image sequences
down-linked from the ISS. In this approach the ISS
camera orientations were computed from known coordinates of several reference points on the ISS hardware. Then the
position of the jettisoned object for each time-frame was computed from its image in each frame of the video-clips. In
another, "quick-look" approach used in near-real time, orientation of the cameras was computed from their position
(from the ISS CAD model) and operational data (pan and tilt) then location of the jettisoned object was calculated only
for several frames of the two synchronized movies.
Metal targets covered by micrometer layers of metal- phthalocyanines or fullerenes are studied here. An increase in XUV yield due to the optimized absorption of the laser field is reported. Effects of high-temperature plasma rapid expansion were observed. Moderate power nanosecond and picosecond neodymium lasers are used to produce an incident intensity of 1011 to 1013 W/cm2 on the targets. The plasma electron density was measured by fitting observed spectral profiles to the theoretical profiles. Collisional, Doppler, and Stark broadening mechanisms were considered in the calculations. Our measurement technique permits us to determine the electron density and temperature dependence on distances from the target surface from 1 mm up to approximately 5 mm. Electron temperature was measured by comparing intensities of spectral lines, belonging to the ions having a different degree of ionization. Preliminary experiments show that conversion efficiency for molecular coated targets is greater by a factor of approximately 1.5 than measured form bulk solid metal targets.
Metal targets covered by micrometer layers of metal- phthalocyanines or fullerenes are studied here. An increase in XUV yield due to the optimized absorption of the laser field is reported. Effects of high-temperature plasma rapid expansion (velocity about 106 cm/s) were observed. Moderate power nanosecond and picosecond neodymium lasers are used to produce an incident intensity of 1011 to 1013 W/cm2 on the targets. The plasma electron density was measured by fitting observed spectral profiles to the theoretical profiles. Collisional, Doppler, and Stark broadening mechanisms were considered in the calculations. Our measurement technique permits us to determine the electron density and temperature dependence on distances from the target surface from 1 mm (where Ne approximately equals 1018 cm-3 and Te approximately equals 14 eV are measured for aluminum plasma) up to approximately 5 mm (where Ne <EQ 1017 cm-3). Electron temperature was measured by comparing intensities of spectral lines, belonging to the ions having a different degree of ionization. Preliminary experiments show that conversion efficiency for molecular coated targets is greater by a factor of approximately 1.5 than measured from bulk solid metal targets.
Soft X-ray radiation from krypton and nitrogen clusters in a supersonic gas jet is studied here. Isolated lines of He- like nitrogen ions in the 1.5 to 3.0 nm wavelengths region and of 7 to 13-charged ions of krypton in the 1.5 to 20 nm region are observed using to 4 to 6 keV electron beam excitation with 50 to 75 mA beam current. The obtained spectra are investigated depending the gas jet flow and excitation parameters.
Metal targets covered by micrometer layers of metal- phthalocyanines are studied here. An increase in EUV yield due to optimized absorption of the laser field is reported. Effects of high-temperature plasma rapid expansion (velocity about 106 cm/s) were observed. Moderate power nanosecond and picosecond neodymium lasers are used to product an incident intensity of 1011 to 1013 W/cm2 on the targets. The plasma electron density was measured by fitting observed spectral profiles to theoretical profiles. Collisional, Doppler, and Stark broadening mechanisms were considered in the calculations. Our measurement technique makes it possible to determine the electron density and temperature dependence on distances from the target surface from 1 mm (where Ne equals 2.0 (+/- 0.5)1018 cm-3 and Te equals 14 eV are measured for aluminum plasma) up to approximately 5 mm (where Ne <EQ 1017 cm-3). Electron temperature was measured by comparing intensities of spectral lines, belonging to the ions having a different degree of ionization. Preliminary experiments show that conversion efficiency for molecular coated targets is greater by a factor of approximately 1.5 than measured from bulk solid metal targets.
Phthalocyanine coated targets, as well as tungsten, aluminum, and carbon targets are studied. Nanosecond and picosecond neodymium lasers capable of moderate output powers are used to produce 1011 to 1013 W/cm2 of incident intensity on the targets. The laser plasma temperature and electron density are measured by recording intensities and spectral shapes of ion lines in a spectral region from 40 to 300 nm. More than ten lines including Al3+ at 76.8 nm, Al2+ at 56 nm, Al+ at 237 nm, C3+ at 253 nm, and C2+ at 297 nm are observed and analyzed. The measurement technique permits us to determine electron density and electron temperature dependencies on the distance form the target surface ranging from 0.5 to 5 mm, where Ne greater than or equal to 1017 cm-3. For example, for an aluminum plasma at a distance 1 mm from the target, Ne equals 5 (plus or minus 1) 1017 cm-3 and Te equals 14 eV, respectively. For a new class of molecular materials (metal-phthalocyanines) an increased XUV output is observed due to effective laser radiation coupling into molecular targets. Different types of coatings (including fullerenes) are currently under investigation.
A spectrometric facility for measurements of reflection, absorption and excitation spectra of films and massive samples in 50 to 300 nm wavelength region with the spectral resolution up to 103 is designed and tested. Plasma produced EUV radiation from the laser beam focused onto a gaseous or a solid target makes it possible to achieve the spectral intensity on a sample up to 3(DOT)106 photons/s(DOT)cm-1. Application to measurement of reflection spectra of some phthalocynines is reported here.
We report the photoluminescence spectrum of well characterized, epitaxially grown single crystal C60 thin films. The highly regular and reproducible spectral features observed can be explained by a simple molecular model which takes into account enhanced coupling of an excited C60 molecule with its nearest neighbor. This model provides an identification of all the observed spectral features at low temperature including a qualitative understanding of the relative peak height ratios, as well as the observed temperature dependence of the PL spectrum.
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