15 research outputs found
Hardware test program for evaluation of baseline range/range rate sensor concept
The test program Phase II effort provides additional design information in terms of range and range rate (R/R) sensor performance when observing and tracking a typical spacecraft target. The target used in the test program was a one-third scale model of the Hubble Space Telescope (HST) available at the MSFC test site where the tests were performed. A modified Bendix millimeter wave radar served as the R/R sensor test bed for evaluation of range and range rate tracking performance, and generation of radar signature characteristics of the spacecraft target. A summary of program test results and conclusions are presented along with detailed description of the Bendix test bed radar with accompaning instrumentation. The MSFC test site and facilities are described. The test procedures used to establish background levels, and the calibration procedures used in the range accuracy tests and RCS (radar cross section) signature measurements, are presented and a condensed version of the daily log kept during the 5 September through 17 September test period is also presented. The test program results are given starting with the RCS signature measurements, then continuing with range measurement accuracy test results and finally the range and range rate tracking accuracy test results
First Results from SPARO: Evidence for Large-Scale Toroidal Magnetic Fields in the Galactic Center
We have observed the linear polarization of 450 micron continuum emission
from the Galactic center, using a new polarimetric detector system that is
operated on a 2 m telescope at the South Pole. The resulting polarization map
extends ~ 170 pc along the Galactic plane and ~ 30 pc in Galactic latitude, and
thus covers a significant fraction of the central molecular zone. Our map shows
that this region is permeated by large-scale toroidal magnetic fields. We
consider our results together with radio observations that show evidence for
poloidal fields in the Galactic center, and with Faraday rotation observations.
We compare all of these observations with the predictions of a magnetodynamic
model for the Galactic center that was proposed in order to explain the
Galactic Center Radio Lobe as a magnetically driven gas outflow. We conclude
that the observations are basically consistent with the model.Comment: 11 pages, 2 figures, 1 table, submitted to ApJ Let
First Results from Viper: Detection of Small-Scale Anisotropy at 40 GHZ
Results of a search for small-scale anisotropy in the cosmic microwave
background (CMB) are presented. Observations were made at the South Pole using
the Viper telescope, with a .26 degree (FWHM) beam and a passband centered at
40 GHz. Anisotropy band-power measurements in bands centered at l = 108, 173,
237, 263, 422 and 589 are reported. Statistically significant anisotropy is
detected in all bands.Comment: 5 pages, 4 figures, uses emulateapj.sty, submitted to ApJ Letter
SOFIA and its facility Far Infrared Camera HAWC
The Stratospheric Observatory For Infrared Astronomy (SOFIA) is a 2.5 m telescope which will fly in a Boeing 747SP, commencing operation
in late summer 2004. SOFIA is a joint American/German project and for
most of this decade it will be the largest far-infrared telescope.
SOFIA will have a suite of instruments available to the astronomical
community, including the High-resolution Airborne Wide-band Camera
(HAWC) - its facility far-infrared camera