ALBERT

Description: The viewgraphs and discussion of the status of the F-16XL SSLFC numerical design validation are provided. The F-16XL Supersonic Laminar Flow Control Program (SSLFC) is a joint effort involving Rockwell's North American Aircraft Division, NASA Ames-Dryden Flight Research Facility, and NASA Langley Research Center. The objectives of the program are to demonstrate that laminar flow can be obtained on a highly swept wing at supersonic speeds, validate the capabilities of a numerical methodology designed to predict boundary layer transition, and validate the capabilities of the methodology in the design of active and passive laminar flow control (LFC) concepts. The F-16XL SSLFC Program consists of the design, fabrication, installation, and flight test of an active laminar flow control glove for the F-16XL. The glove design emphasized the active (suction) control of attachment line and crossflow boundary condition instabilities. The glove design envelop was constrained by the existing geometry, safety of flight considerations, and space requirements for the suction mechanism. The leading edge extension of the glove was limited to 10 inches for consideration of asymmetric flying qualities and the glove height above the existing surface restricted to two inches. The active (suction) portion of the wing extends to nominally 25 percent chord. The glove was constructed of a micro-perforated titanium sheet (hole diameter = 0.025 inches, spacing ratio = 1/8, and sheet thickness = 0.0025 inches). The glove design includes 22 separate chambers to allow suction variation in the chordwise direction. The F-16XL SSLFC program is currently in the flight test phase.

Description: Ventral fin loads, expressed as normal force coefficients, bending moment coefficients, and torque coefficients, were measured during flight tests of a YF-12A airplane. Because of the proximity of the ventral fin to the ailerons, the aerodynamic loads presented were the result of both sideslip loads and aileron crossflow loads. Aerodynamic data obtained from strain gage loads instrumentation and some flight pressure measurements are presented for several Mach numbers ranging from 0.70 to 2.00. Selected wind tunnel data and results of linear theoretical aerodynamic calculations are presented for comparison.

Description: We describe the calibration and data processing methods used to generate full-sky maps of the cosmic microwave background (CMB) from the first year of Wilkinson Microwave Anisotropy Probe (WMAP) observations. Detailed limits on residual systematic errors are assigned based largely on analyses of the flight data supplemented, where necessary, with results from ground tests. The data are calibrated in flight using the dipole modulation of the CMB due to the observatory's motion around the Sun. This constitutes a full-beam calibration source. An iterative algorithm simultaneously fits the time-ordered data to obtain calibration parameters and pixelized sky map temperatures. The noise properties are determined by analyzing the time-ordered data with this sky signal estimate subtracted. Based on this, we apply a pre-whitening filter to the time-ordered data to remove a low level of l/f noise. We infer and correct for a small (approx. 1 %) transmission imbalance between the two sky inputs to each differential radiometer, and we subtract a small sidelobe correction from the 23 GHz (K band) map prior to further analysis. No other systematic error corrections are applied to the data. Calibration and baseline artifacts, including the response to environmental perturbations, are negligible. Systematic uncertainties are comparable to statistical uncertainties in the characterization of the beam response. Both are accounted for in the covariance matrix of the window function and are propagated to uncertainties in the final power spectrum. We characterize the combined upper limits to residual systematic uncertainties through the pixel covariance matrix.

Description: We present the list of point sources found in the WMAP 5-year maps. The technique used in the first-year and three-year analysis now finds 390 point sources, and the five-year source catalog is complete for regions of the sky away from the galactic plane to a 2 Jy limit, with SNR greater than 4.7 in all bands in the least covered parts of the sky. The noise at high frequencies is still mainly radiometer noise, but at low frequencies the CMB anisotropy is the largest uncertainty. A separate search of CMB-free V-W maps finds 99 sources of which all but one can be identified with known radio sources. The sources seen by WMAP are not strongly polarized. Many of the WMAP sources show significant variability from year to year, with more than a 2:l range between the minimum and maximum fluxes.

Description: We present a new estimate of foreground emission in the WMAP data, using a Markov chain Monte Carlo (MCMC) method. The new technique delivers maps of each foreground component for a variety of foreground models, error estimates of the uncertainty of each foreground component, and provides an overall goodness-of-fit measurement. The resulting foreground maps are in broad agreement with those from previous techniques used both within the collaboration and by other authors. We find that for WMAP data, a simple model with power-law synchrotron, free-free, and thermal dust components fits 90% of the sky with a reduced X(sup 2) (sub v) of 1.14. However, the model does not work well inside the Galactic plane. The addition of either synchrotron steepening or a modified spinning dust model improves the fit. This component may account for up to 14% of the total flux at Ka-band (33 GHz). We find no evidence for foreground contamination of the CMB temperature map in the 85% of the sky used for cosmological analysis.

Description: The Wilkinson Microwave Anisotropy Probe (WMAP), launched in 2001, has mapped out the Cosmic Microwave Background with unprecedented accuracy over the whole sky. Its observations have led to the establishment of a simple concordance cosmological model for the contents and evolution of the universe, consistent with virtually all other astronomical measurements. The WMAP first-year and three-year data have allowed us to place strong constraints on the parameters describing the ACDM model. a flat universe filled with baryons, cold dark matter, neutrinos. and a cosmological constant. with initial fluctuations described by nearly scale-invariant power law fluctuations, as well as placing limits on extensions to this simple model (Spergel et al. 2003. 2007). With all-sky measurements of the polarization anisotropy (Kogut et al. 2003; Page et al. 2007), two orders of magnitude smaller than the intensity fluctuations. WMAP has not only given us an additional picture of the universe as it transitioned from ionized to neutral at redshift z approx.1100. but also an observation of the later reionization of the universe by the first stars. In this paper we present cosmological constraints from WMAP alone. for both the ACDM model and a set of possible extensions. We also consider tlle consistency of WMAP constraints with other recent astronomical observations. This is one of seven five-year WMAP papers. Hinshaw et al. (2008) describe the data processing and basic results. Hill et al. (2008) present new beam models arid window functions, Gold et al. (2008) describe the emission from Galactic foregrounds, and Wright et al. (2008) the emission from extra-Galactic point sources. The angular power spectra are described in Nolta et al. (2008), and Komatsu et al. (2008) present and interpret cosmological constraints based on combining WMAP with other data. WMAP observations are used to produce full-sky maps of the CMB in five frequency bands centered at 23, 33, 41, 61, and 94 GHz (Hinshaw et al. 2008). With five years of data, we are now able to place better limits on the ACDM model. as well as to move beyond it to test the composition of the universe. details of reionization. sub-dominant components, characteristics of inflation, and primordial fluctuations. We have more than doubled the amount of polarized data used for cosmological analysis. allowing a better measure of the large-scale E-mode signal (Nolta et al. 2008). To this end we describe an alternative way to remove Galactic foregrounds from low resolution polarization maps in which Galactic emission is marginalized over, providing a cross-check of our results. With longer integration we also better probe the second and third acoustic peaks in the temperature angular power spectrum, and have many more year-to-year difference maps available for cross-checking systematic effects (Hinshaw et al. 2008).

Description: The Wilkinson Microwave Anisotropy Probe (WMAP) is a Medium-Class Explorer (MIDEX) satellite aimed at elucidating cosmology through full-sky observations of the cosmic microwave background (CMB). The WMAP full-sky maps of the temperature and polarization anisotropy in five frequency bands provide our most accurate view to date of conditions in the early universe. The multi-frequency data facilitate the separation of the CMB signal from foreground emission arising both from our Galaxy and from extragalactic sources. The CMB angular power spectrum derived from these maps exhibits a highly coherent acoustic peak structure which makes it possible to extract a wealth of information about the composition and history of the universe. as well as the processes that seeded the fluctuations. WMAP data have played a key role in establishing ACDM as the new standard model of cosmology (Bennett et al. 2003: Spergel et al. 2003; Hinshaw et al. 2007: Spergel et al. 2007): a flat universe dominated by dark energy, supplemented by dark matter and atoms with density fluctuations seeded by a Gaussian, adiabatic, nearly scale invariant process. The basic properties of this universe are determined by five numbers: the density of matter, the density of atoms. the age of the universe (or equivalently, the Hubble constant today), the amplitude of the initial fluctuations, and their scale dependence. By accurately measuring the first few peaks in the angular power spectrum, WMAP data have enabled the following accomplishments: Showing the dark matter must be non-baryonic and interact only weakly with atoms and radiation. The WMAP measurement of the dark matter density puts important constraints on supersymmetric dark matter models and on the properties of other dark matter candidates. With five years of data and a better determination of our beam response, this measurement has been significantly improved. Precise determination of the density of atoms in the universe. The agreement between the atomic density derived from WMAP and the density inferred from the deuterium abundance is an important test of the standard big bang model. Determination of the acoustic scale at redshift z = 1090. Similarly, the recent measurement of baryon acoustic oscillations (BAO) in the galaxy power spectrum (Eisenstein et al. 2005) has determined the acoustic scale at redshift z approx. 0.35. When combined, these standard rulers accurately measure the geometry of the universe and the properties of the dark energy. These data require a nearly flat universe dominated by dark energy consistent with a cosmological constant. Precise determination of the Hubble Constant, in conjunction with BAO observations. Even when allowing curvature (Omega(sub 0) does not equal 1) and a free dark energy equation of state (w does not equal -1), the acoustic data determine the Hubble constant to within 3%. The measured value is in excellent agreement with independent results from the Hubble Key Project (Freedman et al. 2001), providing yet another important consistency test for the standard model. Significant constraint of the basic properties of the primordial fluctuations. The anti-correlation seen in the temperature/polarization (TE) correlation spectrum on 4deg scales implies that the fluctuations are primarily adiabatic and rule out defect models and isocurvature models as the primary source of fluctuations (Peiris et al. 2003).

Description: Upper surface oil-flow photographs were obtained at transonic speeds on an F-111 transonic aircraft technology (TACT) aircraft, which had been fitted with a natural laminar-flow airfoil section. The oil-flow photographs were interpreted with regard to shock and boundary-layer characteristics and compared to results obtained from pressure distributions and boundary-layer measurements. Results indicated that flow phenomena (such as shock location and strength) and chord location of boundary-layer characteristics (such as transition location) could be correctly identified from the oil-flow photographs.

Description: Recently, two aircraft from the Dryden Flight Research Facility were used in the general study of natural laminar flow (NLF). The first, an F-14A aircraft on short-term loan from the Navy, was used to investigate transonic natural laminar flow. The second, an F-15A aircraft on long-term loan from the Air Force, was used to examine supersonic NLF. These tests were follow-on experiments to the NASA F-111 NLF experiment conducted in 1979. Both wings of the F-14A were gloved, in a two-phased experiment, with full-span(upper surface only) airfoil shapes constructed primarily of fiberglass, foam, and resin. A small section of the F-15A right wing was gloved in a similar manner. Each glove incorporated provisions for instrumentation to measure surface pressure distributions. The F-14A gloves also had provisions for instrumentation to measure boundary layer profiles, acoustic environments, and surface pitot pressures. Discussions of the techniques used to construct the gloves and to incorporate the required instrumentation are presented.