Disadvantages of In-Office Whitening. 1  In-office bleaching is more expensive than take-home alternatives. 2  Its cost, on average, is $650, compared to $400 for take-home trays and under $100 for over-the-counter bleaching trays or whitening strips.
Planetary protection is a guiding principle in the design of an interplanetary mission, aiming to prevent biological contamination of both the target celestial body and the Earth in the case of sample-return missions.
Weather Library > How lightning protection systems work. Lightning protection systems are the modern development of the innovation pioneered by Benjamin Franklin: the lightning rod. Today, lightning protection systems are in use on thousands of buildings, homes, factories, towers, and even the Space Shuttle's launch pad. This article will examine why lightning protection is necessary and what the systems can and cannot do. In This Article: - Components of a lightning protection system.