Flying gas stations that can refuel robotic military aircraft have come a step closer . The first ever mid-air refuelling of an unmanned aircraft was today successfully achieved by the Navy 's X-47B drone . The Salty Dog 502 vehicle is one of two Unmanned Carrier Air Vehicle demonstrators ( UCAS-D ) on the X-47B program . Scroll down for video . The first mid-air refuelling of an unmanned aircraft was today successfully achieved by the Navy 's X-47B drone . Earlier today , the aircraft plugged its in-flight refuelling ( IFR ) probe into the hose of an Omega Air KC-707 tanker off the coast of Maryland . Earlier today , it plugged its in-flight refuelling ( IFR ) probe into the hose of an Omega Air KC-707 tanker off the coast of Maryland . During the test , it trailed the Omega Air Refuelling 707 tanker from a mile off before using optical sensors and a video camera to monitor its approach to within 20 feet ( six metres ) . Depending on the weather , the aerial refuelling demonstrations are due to last throughout the weekend . The drone is about the size of an F/A-18 Super Hornet , weighs in at 44,000 lb ( 20,000kg ) and has a 62ft ( 20m ) wingspan . Salty Dog 502 is one of two Unmanned Carrier Air Vehicle demonstrators ( UCAS-D ) on the X-47B program . The goal of each of the refuelling demonstrations is to transfer 3,000lbs of fuel in five minutes . But this is the final test of the historic X-47B , which will now be donated to museums despite , according to Foxtrot Alpha , only having 20 per cent of their flight hours used up . Refuelling in flight is the last hurdle for the Northrop Grumman-built jet , claims to Captain Beau Duarte , program manager of the Navy 's Unmanned Carrier Aviation . With a wingspan of 130 feet , the Triton is wider than commercial airliners such as the Boeing 737 . An airliner-sized Navy surveillance drone made its first transcontinental flight in September , flying 11 hours across the US . The cross-country test was the first for the MQ-4C Triton , which will play a role in the Navy 's planned Broad Area Maritime Surveillance program . The drone can provide blanket surveillance for the Navy as part of the branch 's Broad Area Maritime Surveillance program . Triton uses 'radar , infrared sensors and advanced cameras to provide full-motion video and photographs ' to Navy personnel . Northrop Grumman says the unmanned aircraft also has a capacity to fly up to 28 hours at a time and surveil 1million square miles in a single mission . With a wingspan of 130 feet , the Triton is wider than commercial airliners such as the Boeing 737 . Mid-air refuelling is difficult enough for human pilots , but the ability for drones to do it could eman they only ever have to land for equipment updates . The Navy envisions the X-47B 's successors , the UCLASS drones , as making 24-7 patrols around aircraft carriers . 'We will have met all of the program 's mission objectives and will [ take ] those lessons learned , fold them into the UCLASS performance specification , ' Duarte said . The X-47B drone is about the size of an F/A-18 Super Hornet , weighs in at 44,000 lb ( 20,000kg ) and has a 62ft ( 20m ) wingspan .
Salty Dog 502 trailed Omega Air Refuelling 707 tanker from a mile off . It used optical sensors and a camera to monitor approach to 20 feet . It then plugged its refuelling probe into hose of Drone . the Omega Air KC-707 is size of an F/A-18 Super Hornet and weighs 44,000lb ( 20,000kg )