The solar probe shield/antenna materials characterization

Citation
J. Randolph et al., The solar probe shield/antenna materials characterization, CARBON, 37(11), 1999, pp. 1731-1739
Citations number
14
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
CARBON
ISSN journal
0008-6223 → ACNP
Volume
37
Issue
11
Year of publication
1999
Pages
1731 - 1739
Database
ISI
SICI code
0008-6223(1999)37:11<1731:TSPSMC>2.0.ZU;2-X
Abstract
This paper describes the development process used to select the shield/ante nna material satisfying the design requirements of the Solar Probe mission that will encounter a flux at perihelion equivalent to an intensity of 3000 times greater than that at the Earth. A joint U.S.-French testing program was devised that would screen samples of carbon-carbon to determine the fab rication process that would produce the best thermal-optical and thermal-me chanical properties, lowest mass loss, and acceptable RF properties for tem peratures up to 2400 K during shield operation. The thermal optical propert ies are emphasized since these determine the operating temperature and mass loss of the shield and are the most uncertain. The U.S. optical testing pr ogram relied on two facilities. The first facility used a high intensity ha logen lamp to heat the sample. The temperature data were used in a heat bal ance equation to determine the solar absorptance/infrared emittance (alpha/ epsilon) ratio given the known heat flux input. The emittance of the sample s was determined, independently, by another specially calibrated facility t hat used Joule heating of the samples and measured the temperature by remot e pyrometry that had been precisely calibrated. The French testing utilized a precisely designed chamber facility at the CNRS 1000 kW Solar Furnace at Odeillo Font Romeu and the data collected there are sufficient to identify the thermal-optical properties of the materials, as well as their mass los s characteristics at high temperatures including the principal carbon vapor species evolved. (C) 1999 Elsevier Science Ltd. All rights reserved.