Comet Wild 2
Comet 81 P/Wild, also named Wild 2, was discovered in 1978. After a passage close to Jupiter in 1974, its orbit moved toward the inner solar system, with a high ellipticity and a short period (6.4 years). Its perihelion is close to 1 AU. In January 2004, comet Wild 2 was approached by the Stardust spacecraft which collected cometary grains from its tail and brought them back to Earth in 2006. This cometary matter included material originating from different regions of the solar system before being incorporated into the comet nucleus. The presence of glycine, the simplest amino acid, has been reported in the cometary samples. Comet Wild 2 is the only comet for which samples have been brought back to Earth and analyzed.