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Thousands of satellites circle our planet, many relying on TI space-qualified electronics to monitor changes in climate and oceans, improve farm yields, and provide us with communications, navigation, and other scientific data.
Space, however, is the most unforgiving of all operating environments. The harsh environment requires that the electronic components used in making satellites must withstand a wide variety of challenges ranging from hundreds of degrees of temperature change to massive amounts of radiation. Added to the mix is an expectation of flawless functioning for decades, usually without the possibility of upgrades or performance tweaks.
Outside the protective cover of the Earth’s atmosphere, the solar system is filled with radiation that can damage electronic devices. The effects range from performance degradation to complete functional failure.
Most Components and Materials Not Made for Space
These harsh conditions mean that commercial off-the-shelf (COTS) components can’t be used for space missions. Some space programs have investigated using automotive-grade AEC-Q100 products with more stringent qualification requirements added. However, the extra qualification steps in Q100 parts still don’t meet all of the necessities of a space application.
Thus, there are strict limits on materials that can be used in space, which may endure phenomena such as outgassing. Outgassing is a process whereby the harsh temperature and vacuum conditions of space vaporize organic compounds from materials like plastic, glues, and adhesives, and then they’re deposited onto electronics, causing them to fail.
What’s more, substances such as cadmium and zinc will disintegrate in low pressures, and other metals like tin will develop metallic whiskers—called dendrites—that could bridge electrical connections and induce shorts and component failures.
Tin whiskers are electrically conductive, crystalline structures that sometimes grow from surfaces where tin is used as a final finish. To counteract this possibility, finishes on spacecraft components are either nickel-palladium-gold or 63% tin/37% lead to reduce the risk of tin-whisker-induced failures.
Device Selection for the Mission at Hand
To enable shorter development times, Texas Instruments’ Space EP products provide extensive radiation characterization to meet the requirements of space missions (Fig. 1).