Washington, Jumada II 01, 1437, March 10, 2016, SPA -- An unmanned mission to study Mars' interior, postponed after difficulties repairing an instrument crucial to the mission's goal, will launch on May 5, 2018, NASA said Wednesday, according to dpa. The launch of NASA's InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) Mars lander was originally set for March 2016 but postponed indefinitely in December. An extremely sensitive instrument used to measure seismic activity developed a leak in its vacuum seal, which continued to fail after twice undergoing repair. Officials from the US space agency said the needed fix was not possible before the original launch date. Favourable alignment of Earth and Mars occurs for only a few weeks every 26 months, and March 2016 was when that window would next occur. "The quest to understand the interior of Mars has been a longstanding goal of planetary scientists for decades. We're excited to be back on the path for a launch, now in 2018," NASA administrator John Grunsfeld said. --SPA 03:09 LOCAL TIME 00:09 GMT www.spa.gov.sa/w