Berlin/Frankfurt, Muharram 19, 1436, Nov 12, 2014, SPA -- The European Space Agency (ESA) landed a probe on a comet on Wednesday, a first in space exploration and the climax of a decade-long mission to examine up close the remnants of the birth of Earth's solar system, Reuters reported. The 100-kg (220-pound) lander - virtually weightless on the comet's surface - touched down on schedule at about 1600 GMT after a seven-hour descent from spacecraft Rosetta around half a billion kilometres (300 million miles) from Earth. During the launch, harpoons designed to anchor the probe, named Philae, failed to deploy and the ESA is having to consider options for refiring them to ensure it does not drift back into space. -- SPA 21:28 LOCAL TIME 18:28 GMT www.spa.gov.sa/w