Engineering topics

Boucarut, Ray

Publications and source records attributed to Boucarut, Ray.

4 records

NASA NTRS2004

Cryo-Infrared Optical Characterization at NASA GSFC

The development of large space infrared optical systems, such as the Next Generation Space Telescope (NGST), has increased requirements for measurement accuracy in the optical properties of materials. Many materials used as optical components in infrared optical systems, have strong temperature dependence in their optical properties. Unfortunately, data on the temperature dependence of most of these materials is sparse. In this paper, we provide a description of the capabilities existing in the Optics Branch at the Goddard Space Flight Center that enable the characterization of the refractive index and absorption coefficient changes and other optical properties in infrared materials at cryogenic temperatures. Details of the experimental apparatus, which include continuous flow liquid helium optical cryostat, and a Fourier Transform Infrared (FTIR) spectrometer are discussed.

Boucarut, Ray↗

NASA NTRS2004

Microshutters Arrays for the JWST Near Infrared Spectrometer

The Near Infrared Spectrograph (NIRSpec) for the James Webb Space Telescope (JWST) is an essential instrument for measuring the number and density evolution of galaxies following the epoch of initial formation. The NIRSpec is a multi-object spectrograph, allowing simultaneous observation of more than 100 candidate high redshift galaxies. A critical element of the instrument is the programmable field selector, the Microshutter Array. The system consists of four 175 x 384 arrays of individually openable shutters, close packed on a 100 x 200 micron pitch, which allow selection of over 200 candidate objects over the 3 min x 3 min field of the NIRSpec. We will describe the development, production, and test of this critical element of the NIRSpec.

Moseley, Harvey↗

NASA NTRS1999

Deformable Mirror Optical Calibration and Test Results

We describe the initial setup, configuration, and component level testing procedures that were used to incorporate a Xinetics 349 channel deformable mirror into the DCATT active optical system. Initial flattening results are presented as well as calibration data on actuator gain and mirror response. The RMS measures of surface quality are also analyzed for drift in the power-up state.

Dean, Bruce H.↗

NASA NTRS1999

Looking at NGST Through the Eyes of DCATT

The first phase of the Developmental Characterized Active Telescope Testbed (DCATT) hardware system was integrated at Goddard Space Flight Center in early March of 1999 and has been operational for almost a year. Experiments are currently being conducted on the testbed to quantify and refine various methods and techniques in the baseline wavefront sensing and control process. This paper addresses the actual optical design of the Phase 0 hardware configuration and discusses the open loop system level performance of the system. Lessons learned for NGST during the buildup and characterization of the system are presented.

Davila, Pam↗