Cometary and Interstellar Dust Analyzer for comet Wild 2

Abstract

The Cometary and Interstellar Dust Analyzer (CIDA) instrument analyzes the composition of individual grains in the cometary coma. As each particle impacts a silver plate, the high-impact energy due to the relative velocity of the spacecraft as it flies through the coma causes the elements and molecular compounds in the particle to become ionized. Using a fast time-of-flight mass spectrometer, a complete set of ions are detected for each impact, from a mass range of 1 (atomic hydrogen) up to a few thousand atomic mass units, encompassing all elements in the periodic table and many molecules, such as organic compounds. This experimental technique has already been applied with excellent success at Halley's comet, and the CIDA derivative instrument is flying on the Stardust mission, which will encounter comet Wild 2 in January of 2004. The data returned will give clues to the elemental and chemical composition of the dust component of this comet.