The CRS-5 mission lifted off today in a pre-dawn launch at 4:47 am EST from Space Launch Complex 40 at Cape Canaveral Air Force Station, Florida. As the unmanned spacecraft rose into orbit to resupply the International Space Station, the first stage of its Falcon 9 booster made an historic attempt at a powered landing on a drone barge positioned in the Atlantic Ocean, which did not come off successfully.

CRS-5 launched under scattered clouds as the Falcon 9 generated 1.3 million lb of thrust. One minute and ten seconds into the flight, the spacecraft went through its area of maximum aerodynamic pressure, called max Q, and the first stage engines cut out at two minutes and 37 seconds. Traveling at an altitude of 50 miles (80 km) and ten times the speed of sound, the first stage separated from the second, which propelled the Dragon into orbit with a seven-minute burn.

Normally, this would have been the end for the Falcon 9 booster as it crashed back into the Earth's atmosphere, but as part of SpaceX's program to develop a completely reusable spaceflight system, today's launch was followed by an experimental power landing of the rocket on an "autonomous spaceport drone ship," which is a custom-built platform measuring 300 x 100 ft (91 x 30 m) with wings extending the width to 170 ft (52 m), and uses computerized thrusters to keep stationary.