Low-Stress Silicon Cladding for Surface Finishing Large UVOIR Mirrors, Phase I

Metadata Updated: May 2, 2019

In this Phase I research, ZeCoat Corporation will develop an affordable, low-stress silicon cladding process which is super-polishable for large UVOIR mirrors. The proposed ion-assisted evaporation process is directly scaleable to SiC mirrors several meters in diameter. The process is based on a novel, low temperature, ion-assisted, evaporation technique (IAD), whereby the coating stress of a silicon film may be manipulated from compressive to tensile, in order to produce a near-zero net stress for the complete layer. A cladding with little intrinsic stress is essential to minimize bending that would otherwise distort the figure of very lightweight mirrors.
Current methods to produce a polishable silicon cladding utilize CVD processes that produce highly stressed Si coatings. The current processes require high-temperatures (hundreds of degrees Celsius) and are not readily scaleable to large mirrors. CVD Si cladding is currently limited to mirror substrates less than 1-meter in diameter. The proposed IAD process produces little heat, and the mirror size is limited only by the size of the vacuum chamber. Large silicon carbide (SiC) mirrors (3-4 meters in diameter) are being considered for future space-based UVOIR astronomy missions. These lightweight mirrors will likely require a highly-polishable layer of silicon (10 to 50 microns) applied on top of the SiC. A relatively thick layer of Si is desirable for the purpose of reducing figuring time and for achieving a super-polished surface, suitable for UV astronomy. Normal incidence 4-meter class UVOIR telescopes have been cited as a high priority by multiple government review panels including; the National Research Council's (NRC) study of NASA's Space Technology Roadmap and Priorities, The Office of the Chief Technologist, The Cosmic Origins Program and NWNH Decadal.

Access & Use Information

Public: This dataset is intended for public access and use. License: U.S. Government Work

Downloads & Resources

Dates

Metadata Created Date August 1, 2018
Metadata Updated Date May 2, 2019

Metadata Source

Harvested from NASA Data.json

Additional Metadata

Resource Type Dataset
Metadata Created Date August 1, 2018
Metadata Updated Date May 2, 2019
Publisher Space Technology Mission Directorate
Unique Identifier TECHPORT_16654
Maintainer
TECHPORT SUPPORT
Maintainer Email
Public Access Level public
Bureau Code 026:00
Metadata Context https://project-open-data.cio.gov/v1.1/schema/catalog.jsonld
Metadata Catalog ID https://data.nasa.gov/data.json
Schema Version https://project-open-data.cio.gov/v1.1/schema
Catalog Describedby https://project-open-data.cio.gov/v1.1/schema/catalog.json
Datagov Dedupe Retained 20190501230127
Harvest Object Id 464e9dcd-e63e-4707-99c7-860f5ee2a538
Harvest Source Id 39e4ad2a-47ca-4507-8258-852babd0fd99
Harvest Source Title NASA Data.json
Data First Published 2013-11-01
Homepage URL https://techport.nasa.gov/view/16654
License http://www.usa.gov/publicdomain/label/1.0/
Data Last Modified 2018-07-19
Program Code 026:027
Source Datajson Identifier True
Source Hash 0ee415f86c07bf8509eaee58247d917be95e3488
Source Schema Version 1.1

Didn't find what you're looking for? Suggest a dataset here.