- Corrosion in space
Corrosion in space is the corrosion of materials occurring in outer space. Instead of moisture and oxygen acting as the primary corrosion causes, the materials exposed to outer space are subjected to vacuum, bombardment by ultraviolet light and x-rays, high-energy charged particles (mostly electrons and protons from the solar wind). In the upper layers of the atmosphere (between 90–800 km), the atmospheric atoms, ions and free radicals, most notably atomic oxygen, play major role. The concentration of atomic oxygen depends on altitude and solar activity, as the bursts of ultraviolet radiation cause photodissociation of molecular oxygen. Between 160 and 560 km, the atmosphere consists of about 90% atomic oxygen.
Corrosion in space has the highest impact on spacecraft with moving parts. Early satellites tended to develop problems with seizing bearings. Now the bearings are coated with a thin layer of gold.
Different materials resist corrosion in space differently. For example, aluminium is slowly eroded by atomic oxygen, while gold and platinum are highly corrosion-resistant. Gold-coated foils and thin layers of gold on exposed surfaces are therefore used to protect the spacecraft from the harsh environment. Thin layers of silicon dioxide deposited on the surfaces can also protect metals from the effects of atomic oxygen; eg, the Starshine 3 satellite aluminium front mirrors were protected that way. However, the protective layers are subject to erosion by micrometeorites.
Many plastics are considerably sensitive to atomic oxygen and ionizing radiation. Coatings resistant to atomic oxygen are a common protection method, especially for plastics. Silicone-based paints and coatings are frequently employed, due to their excellent resistance to radiation and atomic oxygen. However, the silicone durability is somewhat limited, as the surface exposed to atomic oxygen is converted to silica which is brittle and tends to crack.
The process of space corrosion is being actively investigated. One of the efforts aims to design a sensor based on zinc oxide, able to measure the amount of atomic oxygen in the vicinity of the spacecraft; the sensor relies on drop of electrical condictivity of zinc oxide as it absorbs further oxygen.
The outgassing of volatile silicones on low Earth orbit devices leads to presence of a cloud of contaminants around the spacecraft. Together with atomic oxygen bombardment, this may lead to gradual deposition of thin layers of carbon-containing silicon dioxide. Their poor transparency is a concern in case of optical systems and solar panels. Deposits of up to several micrometers were observed after 10 years of service on the solar panels of the Mir space station.
Other sources of problems for structures subjected to outer space are erosion and redeposition of the materials by sputtering caused by fast atoms and micrometeorites. Another major concern, though of non-corrosive kind, is material fatigue caused by cyclical heating and cooling and associated thermal expansion mechanical stresses.
- ^ The Use of Silicone Adhesives in Space Applications
- ^ Optimizing Atomic Oxygen Resistance on Coated Substrates Using TechOptimizer
- ^ Banks, Bruce A.; De Groh, Kim K.; Rutledge, Sharon K.; Haytas, Christy A. (1999). "Consequences of atomic oxygen interaction with silicone and silicone contamination on surfaces in low earth orbit". Proc. SPIE 3784: 62. Bibcode 1999SPIE.3784...62B.
- Failure in spacecraft systems
- New Scientist premium article: Space is corrosive
- NASA Long Duration Exposition Facility: surface contamination in space
Wikimedia Foundation. 2010.
Look at other dictionaries:
Corrosion — v · d · e Materials failure modes Buckling · … Wikipedia
Space solar power — Space based solar power (SBSP or SSP) is the conversion of solar energy into power, usable either in space or on earth, from a location in space, usually geosynchronous orbit (GSO). Photovoltaics (PV) would generally be utilized for energy… … Wikipedia
Space elevator safety — There are many safety issues associated with the construction and operation of a space elevator. A space elevator would present a considerable navigational hazard, both to aircraft and spacecraft. Aircraft could be dealt with by means of simple… … Wikipedia
Space Foundation — The Space Foundation is a nonprofit organization that supports the global space industry through information and education programs. It is a resource for the entire space community industry, national security organizations, civil space agencies,… … Wikipedia
Space-based solar power — Left: Part of the solar energy is lost on its way through the atmosphere by the effects of reflection and absorption. Right: Space based solar power systems convert sunlight to microwaves outside the atmosphere, avoiding these losses, and the… … Wikipedia
Space Needle — Infobox Skyscraper building name = Space Needle built = 1961 1962 use = mixed, tourist attraction caption = Space Needle from Volunteer Park with the EMP building and monorail on bottom. location = Seattle, Washington, United States of America… … Wikipedia
Space Pen — La versión actual de este artículo o sección parece estar escrita a modo de publicidad. Para satisfacer los estándares de calidad de Wikipedia y procurar un punto de vista neutral, este artículo o sección puede requerir limpieza. Por favor… … Wikipedia Español
Monkeys in space — Sam, a Rhesus monkey, flew to an altitude of 88 km in 1959. (NASA) Before humans went into space, several animals were launched into space, including numerous monkeys, so that scientists could investigate the biological effects of space travel.… … Wikipedia
Cape Canaveral Air Force Station Space Launch Complex 40 — Coordinates: 28°33′44″N 80°34′38″W / 28.562106°N 80.577180°W / 28.562106; 80.577180 … Wikipedia
Kennedy Space Center Launch Complex 39 — Launch Complex 39 redirects here. For the Proton launch complex at Baikonur, see Baikonur Cosmodrome Site 200. Launch Complex 39 An aerial view of Launch Complex 39 Launch site Kennedy Space Center Locat … Wikipedia