SpaceX stands down Falcon launch

SpaceX was forced on Monday to postpone its latest commercial cargo re-supply mission to the space station. About 80 minutes before the company’s Falcon-9 rocket was due to make a 16:58 local time (20:58 GMT) lift-off from the Kennedy Space Center, engineers called a halt to proceedings. Sensors indicated a helium leak in the vehicle’s first-stage. 
SpaceX’s next opportunity to get the rocket and its Dragon freighter off the ground will be on Friday. The company is looking to send up just over two tonnes of food, science experiments and general equipment, including spacesuit spares and a set of legs for the station’s Robonaut robot.
The mission will see also SpaceX try to advance the technology needed to recover and re-use Falcon rocket parts. Engineers have fitted landing legs to the vehicle’s first-stage. Normally, this stage is discarded at 80km in altitude almost three minutes into a flight, whereupon it begins a destructive dive back through the atmosphere.
SpaceX wants to be able to recover these stages in good working order, to refurbish them and then to put them back on the launch pad. This could help push down the cost of future space access. Following first-stage separation on the upcoming mission, the lower segment of the Falcon will re-light some of its engines to slow its fall to Earth.