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PICA Forebody Heatshield Qualification for the Stardust Discovery Class MissionThis paper presents the qualification of the light weight Phenolic Impregnated Carbon Ablators (PICA) as the forebody heatshield for the Stardust Discovery Class Mission. The Stardust spacecraft will be launched in early 1999 and fly by Comet Wild-2 to collect cometary and interstellar dust and return them back to earth in the Sample Return Capsule (SRC). This earth re-entry will be the fastest to date, at 12.6 km/s, and therefore requires a heatshield that can withstand very high heating rates and stagnation pressures, as well as provide the necessary insulation to the vehicle structure. The PICA material was developed as part of the Lightweight Ceramic Ablators program at NASA Ames Research Center, and was baselined as the forebody heatshield because of its low density and superior ablation and thermal performance at severe aerothermodynamic conditions. Under a Small Business Innovative Research (SBIR) program with NASA Ames, Fiber Materials, Inc. developed a process to manufacture a single-piece PICA heatshield for the forebody of the SRC, along with witness material for the fabrication of the test models. The test models were fabricated and instrumented by the staff of Lockheed Martin Astronautics in Denver, Colorado. Full body preliminary aerothermal CFD calculations were performed at NASA Ames to determine the heating and stagnation pressure conditions. The Heat shield sizing was also performed at NASA Ames by using a new material response code that accounts for the highly porous characteristics of the PICA material. The ablation and thermal performance of PICA was qualified in the NASA Ames Interaction Heating Arc Jet Facility. A total of 24 models and four test conditions were used to qualify PICA at the predicted peak heat flux, heat load, shear, and stagnation pressure conditions. Surface and in-depth temperatures were measured using optical pyrometers and thermocouples. Surface recession was measured by using a template and a height gage. Several models were tested to evaluate repair procedures, and two models were cold soaked in liquid nitrogen, prior th testing, to investigate the effect of the cold space environment on the performance of the material. In addition, material cored from a demonstration single-piece heatshield was tested to verify that the PICA process can be successfully completed on a large, complex heatshield shape.
Document ID
20020040895
Acquisition Source
Ames Research Center
Document Type
Conference Paper
Authors
Tran, Huy K.
(NASA Ames Research Center Moffett Field, CA United States)
Johnson, Christine E.
(NASA Ames Research Center Moffett Field, CA United States)
Hsu, Ming-Ta
(Chem (H. C.) Co. Moffett Field, CA United States)
Smith, Marnell
(Chem (H. C.) Co. Moffett Field, CA United States)
Dill, Harry
(Orbital Sciences Corp. United States)
Rasky, Daniel J.
Date Acquired
August 20, 2013
Publication Date
January 1, 1996
Subject Category
Nonmetallic Materials
Meeting Information
Meeting: 32nd AIAA Thermophysics Conference
Location: Atlanta, GA
Country: United States
Start Date: June 23, 1997
End Date: June 25, 1997
Sponsors: American Inst. of Aeronautics and Astronautics
Funding Number(s)
PROJECT: RTOP 242-80-01
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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