... The study of extra solar planets will be one of the most important areas of research in astronomy in this century. ... The first planets outside the solar system were found in 1992 around the millisecond pulsar PSR B1257+12 by Alex Wolszczan at the Arecibo Observatory . ... Three space missions based on this principle (MOST, COROT and Kepler ) have already been launched or approved, and have the last one at least has the potential to find Earth-sized planets. ... SIM ( NASA ) is one of such missions...