Pillinger was the principal investigator for "Beagle 2" Mars lander project, part of European Space Agency's (ESA) 2003 "Mars Express" mission. Initially considered a failure, it has since come to light that the space craft did successfully touch down on the surface of Mars. The UK Space Agency on 16 January 2015 indicated that "Beagle 2" had indeed reached the surface of Mars on 25 December 2003, but had failed to deploy fully. Images taken by the HiRISE camera on NASA's "Mars Reconnaissance Orbiter" (MRO) identified clear evidence for the lander and convincing evidence for key entry and descent components on the surface of Mars within the expected landing area of Isidis Planitia (an impact basin close to the equator).