 The exploration of Mars has come at a considerable financial cost with roughly two-thirds of all spacecraft destined for Mars failing before completing their missions, with some failing before they even began.Such a high failure rate can be attributed to the complexity and large number of variables involved in an interplanetary journey, and has led researchers to jokingly speak of "The Great Galactic Ghoul" which subsists on a diet of Mars probes.This phenomenon is also informally known as the "Mars Curse".