Selecting the right adhesive for space applications is extremely important, mainly due to the high vacuum (around 10-8 Torr) and the variation in temperatures. A key concern is the outgassing property of these adhesives. Any outgassing might lead to contamination of electronic or optical components, which can have a drastic impact on the optical properties of the system.
Since outgassing is an important consideration in selecting the right adhesive for a space application, NASA and many other government agencies require these adhesives to pass the ASTM E-595 outgassing test. This test requires the total mass loss (TML) and collected volatile condensable materials (CVCM) to be less than 1% and 0.1%, respectively. TML is the weight of the product lost after an exposure to vacuum (less than 5 x 10-5) for 24 hours at 125°C. CVCM is the amount of volatiles which condense in a plate maintained at 25°C. Curing schedule also plays a vital role in achieving the best low outgassing properties.
Apart from low outgassing, excellent resistance to temperatures over a wide range is a desired property for adhesives in space applications. Good performance at very low temperatures (around -110°F) is particularly important. Also of major significance for adhesives not sandwiched between two adherends is their capability of withstanding exposure to proton, electron and heavy ion types of radiation.
Master Bond offers an extensive range of products which meet NASA low outgassing specifications combined with resistance to very low and high temperatures. Many of the low outgassing products offer optical clarity, thermal conductivity/electrical insulation, electrical conductivity and cryogenic serviceability.
