Wide Field Infrared Survey Telescope (WFIRST) Observatory Overview

NASA's Wide Field Infrared Survey Telescope (WFIRST) is being designed to deliver unprecedented capability in dark energy and exoplanet science, and to host a technology demonstration coronagraph for exoplanet imaging and spectroscopy. The observatory design has matured since 2013; we present a comprehensive description of the observatory configuration as refined during the WFIRST Phase-A study. The observatory is based on an existing, repurposed 2.4 meter space telescope coupled with a 288 megapixel near-infrared (0.6 to 2 microns) HgCdTe focal plane array with multiple imaging and spectrographic modes. Together they deliver a 0.28 square degree field of view, which is approximately 100 times larger than the Hubble Space Telescope, and a sensitivity that enables rapid science surveys. In addition, the coronagraph technology demonstration will prove the feasibility of new techniques for exoplanet discovery, imaging, and spectral analysis. A composite truss structure meters both instruments to the telescope assembly, and the instruments and the spacecraft are flight serviceable. We present configuration changes since 2013 that improved interfaces, improved testability, and reduced technical risk. We provide an overview of our Integrated Modeling results, performed at an unprecedented level for a phase-A study, to illustrate performance margins with respect to static wavefront error, jitter, and thermal drift

Construction et performances d'un laser chimique HF continu amorcé par une décharge micro-onde

On décrit la construction d'un laser chimique HF continu, basé sur la réaction exothermique F + H2 → HF(v,j) + H. Les atomes de fluor sont produits à partir d'une décharge micro-onde dans le mélange SF6 + He. Les dimensions transversales de la chambre de réaction sont 50 mm de long et 6 mm de haut. L'axe de la cavité optique est normal aux directions d'écoulement de chacun des gaz réagissants, celles-ci faisant entre elles un angle de 72°. La puissance du laser, fonctionnant avec une cavité optique non sélective, est 16 W. L'efficacité chimique correspondante est 3 % et l'efficacité électrique 0,7 %. Le rayonnement se compose de 14 raies correspondant aux transitions Pv( j) de vibration-rotation de la molécule HF : v,j—1 → v — 1,j (v = 1, 2, 3). Lorsqu'une cavité optique sélective est utilisée, le laser peut fonctionner successivement sur 12 raies correspondant aux transitions P1(j) et P2( j). Le gain non saturé de plusieurs transitions P2(j) est environ 0,11 cm-1

Construction et performances d'un laser chimique HF continu amorcé par une décharge micro-onde

In this paper we present the design and discuss the performances of a continuous HF chemical laser, based on the exothermic reaction F + H2 → HF(v,j) + H. Fluorine atoms are produced in a SF6 + He mixture by means of a microwave discharge apparatus. The dimensions of the laser chamber are 50 mm in length and 6 mm high. The F and H2 streams form an angle of 72°, the optical axis being perpendicular to them. The multiline laser power is 16 W with chemical and electrical efficiencies of 3 % and 0.7 % respectively. The output spectrum consists of 14 lines corresponding to vibration-rotation Pv(j) transitions of the HF molecule : v, j — 1 → v — 1, j (v = 1, 2, 3). Under single-line operation, lasing action is observed on 12 lines successively, corresponding to P 1(j) and P2(j) transitions. The unsaturated gain for several P2(j) transitions is approximately 0.11 cm-1.On décrit la construction d'un laser chimique HF continu, basé sur la réaction exothermique F + H2 → HF(v,j) + H. Les atomes de fluor sont produits à partir d'une décharge micro-onde dans le mélange SF6 + He. Les dimensions transversales de la chambre de réaction sont 50 mm de long et 6 mm de haut. L'axe de la cavité optique est normal aux directions d'écoulement de chacun des gaz réagissants, celles-ci faisant entre elles un angle de 72°. La puissance du laser, fonctionnant avec une cavité optique non sélective, est 16 W. L'efficacité chimique correspondante est 3 % et l'efficacité électrique 0,7 %. Le rayonnement se compose de 14 raies correspondant aux transitions Pv( j) de vibration-rotation de la molécule HF : v,j—1 → v — 1,j (v = 1, 2, 3). Lorsqu'une cavité optique sélective est utilisée, le laser peut fonctionner successivement sur 12 raies correspondant aux transitions P1(j) et P2( j). Le gain non saturé de plusieurs transitions P2(j) est environ 0,11 cm-1

Design and preliminary performance of a transverse-flow "quasi-CW" HF chemical laser

Experimental system -- Experimental results and discussion

Multi-Institutional Practice-Patterns in Fetal Congenital Heart Disease Following Implementation of a Standardized Clinical Assessment and Management Plan.

Background Prenatal diagnosis of congenital heart disease has been associated with early-term delivery and cesarean delivery (CD). We implemented a multi-institutional standardized clinical assessment and management plan (SCAMP) through the University of California Fetal-Maternal Consortium. Our objective was to decrease early-term (37-39 weeks) delivery and CD in pregnancies complicated by fetal congenital heart disease using a SCAMP methodology to improve practice in a high-risk and clinically complex setting. Methods and Results University of California Fetal-Maternal Consortium site-specific management decisions were queried following SCAMP implementation. This contemporary intervention group was compared with a University of California Fetal-Maternal Consortium historical cohort. Primary outcomes were early-term delivery and CD. A total of 496 maternal-fetal dyads with prenatally diagnosed congenital heart disease were identified, 185 and 311 in the historical and intervention cohorts, respectively. Recommendation for later delivery resulted in a later gestational age at delivery (38.9 versus 38.1 weeks, P=0.01). After adjusting for maternal age and site, historical controls were more likely to have a CD (odds ratio [OR],1.8; 95% CI, 2.1-2.8; P=0.004) and more likely (OR, 2.1; 95% CI, 1.4-3.3) to have an early-term delivery than the intervention group. Vaginal delivery was recommended in 77% of the cohort, resulting in 61% vaginal deliveries versus 50% in the control cohort (P=0.03). Among pregnancies with major cardiac lesions (n=373), vaginal birth increased from 51% to 64% (P=0.008) and deliveries ≥39 weeks increased from 33% to 48% (P=0.004). Conclusions Implementation of a SCAMP decreased the rate of early-term deliveries and CD for prenatal congenital heart disease. Development of clinical pathways may help standardize care, decrease maternal risk secondary to CD, improve neonatal outcomes, and reduce healthcare costs

Multi-Institutional Practice-Patterns in Fetal Congenital Heart Disease Following Implementation of a Standardized Clinical Assessment and Management Plan.

Background Prenatal diagnosis of congenital heart disease has been associated with early-term delivery and cesarean delivery (CD). We implemented a multi-institutional standardized clinical assessment and management plan (SCAMP) through the University of California Fetal-Maternal Consortium. Our objective was to decrease early-term (37-39 weeks) delivery and CD in pregnancies complicated by fetal congenital heart disease using a SCAMP methodology to improve practice in a high-risk and clinically complex setting. Methods and Results University of California Fetal-Maternal Consortium site-specific management decisions were queried following SCAMP implementation. This contemporary intervention group was compared with a University of California Fetal-Maternal Consortium historical cohort. Primary outcomes were early-term delivery and CD. A total of 496 maternal-fetal dyads with prenatally diagnosed congenital heart disease were identified, 185 and 311 in the historical and intervention cohorts, respectively. Recommendation for later delivery resulted in a later gestational age at delivery (38.9 versus 38.1 weeks, P=0.01). After adjusting for maternal age and site, historical controls were more likely to have a CD (odds ratio [OR],1.8; 95% CI, 2.1-2.8; P=0.004) and more likely (OR, 2.1; 95% CI, 1.4-3.3) to have an early-term delivery than the intervention group. Vaginal delivery was recommended in 77% of the cohort, resulting in 61% vaginal deliveries versus 50% in the control cohort (P=0.03). Among pregnancies with major cardiac lesions (n=373), vaginal birth increased from 51% to 64% (P=0.008) and deliveries ≥39 weeks increased from 33% to 48% (P=0.004). Conclusions Implementation of a SCAMP decreased the rate of early-term deliveries and CD for prenatal congenital heart disease. Development of clinical pathways may help standardize care, decrease maternal risk secondary to CD, improve neonatal outcomes, and reduce healthcare costs