In-Flight and Laboratory Vacuum-Friction Test Results
Abstract
Coefficient of friction measurements were made for six unlubricated metal couples exposed to the space environment aboard the OV-1-13 spacecraft and exposed to laboratory vacuum. Materials studied included mutually soluble, partially soluble, and insoluble metal combinations. Two samples of each material couple were tested in space and in the laboratory using the disk and rider technique. Linear velocity was 0.10 cm/s (2.5 in/min) and rider normal load was 4.45 N (1 lb) for the gold versus silver couples and 8.90 N (2 lb) for the other combinations. Results showed that friction data obtained in a clean ion-pumped laboratory vacuum of 10(exp -10) torr for materials with low mutual solubility can be correlated to operation in the vicinity of a typical scientific spacecraft that is exposed to an ambient pressure as low as 10(exp -12) torr. The expected increase in coefficient of friction with solubility was shown. Material couples with high mutual solubility present the hazard of unpredictable drastic friction increase in orbit which may not be evident in laboratory testing at levels down to 10(exp -10) torr. It was also shown that gross cold welding of unlubricated metals exposed to a satellite environment does not occur.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1973
- Accession Number
- ADA375664
Entities
People
- E. J. Devine
- H. E. Evans
- W. A. Leasure
Organizations
- National Aeronautics and Space Administration