The drone could scour Mars to look for landing sites for a manned mission in the 2020s Nasa will begin testing the craft here on earth at an altitude of 10,000 feet to recreate the conditions faced on the red planet. The drone named the Preliminary Research Aerodynamic Design to Land on Mars, or Prandtl-m, which is a flying wing aircraft is planned to be ready for launch from at high altitude via a balloon…