Return of SpaceX’s Dragon cargo craft delayed

SpaceX's Dragon spacecraft is attached to the International Space Station's Harmony module. Credit: NASA
SpaceX’s Dragon spacecraft is attached to the International Space Station’s Harmony module. Credit: NASA

Rough seas in the Pacific Ocean will keep SpaceX’s Dragon cargo capsule in space a few days longer than planned, with the unpiloted supply ship’s return to Earth now set for Saturday hauling a load of research specimens from the International Space Station back to the ground.

Landing was scheduled for Tuesday in a splashdown zone in the Pacific Ocean west of Baja California, but officials opted to delay the return to Saturday due to high sea states in the area, NASA said Monday.

Berthed at the space station’s Harmony module since Sept. 23, the SpaceX cargo craft delivered nearly 5,000 pounds of supplies and experiments, including a 3D printer, spacesuit batteries, a small satellite deployer, and a $26 million NASA instrument to help meteorologists study the intensification of hurricanes.

On the way back to Earth, the spacecraft’s pressurized cabin will contain refrigerated blood, urine and saliva samples, along with a habitat with 10 rodents, plants grown on the space station, materials specimens, student experiments, cameras and other gear selected for return to Earth for inspection and refurbishment.

The Dragon’s return trip will carry approximately 3,300 pounds of station hardware and experiments packed by astronauts.

SpaceX’s resupply freighter is the only spacecraft capable of returning significant amounts of cargo to Earth. Russia’s Soyuz crew capsule can land with limited cargo, and the space station’s other supply ships from Orbital Sciences Corp., Russia, Europe and Japan are designed to burn up during re-entry to dispose of trash.

Operating on commands from mission control, the space station’s robotic arm will grapple the Dragon cargo capsule and remove it from the Harmony module’s Earth-facing docking port early Saturday.

Astronauts Reid Wiseman and Barry “Butch” Wilmore will oversee the robot arm’s release of the 12-foot-diameter solar-powered Dragon spaceship at 9:56 a.m. EDT (1356 GMT) Saturday.

The Dragon’s Draco maneuvering thrusters will conduct three burns to depart the vicinity of the space station, then the craft will close and latch the door to its navigation bay before setting up for a de-orbit burn at 2:43 p.m. EDT (1843 GMT).

The spaceship will jettison its unpressurized trunk section and solar panels a few minutes later to burn up in the atmosphere, while the main module re-enters cocooned inside a specialized ablative heat shield developed by NASA and SpaceX to withstand temperatures reaching up to 3,000 degrees Fahrenheit on its hypersonic approach to a landing zone off the coast of Baja California.

Dual drogue parachutes will deploy when the capsule passes an altitude of about 45,000 feet, then three 116-foot-diameter main chutes will open to slow down the craft’s descent to a gentle 10 mph for splashdown at 3:39 p.m. EDT (1939 GMT).

A maritime recovery team will be on standby to recover the capsule from the Pacific Ocean and ferry it back to port in Long Beach, Calif., where SpaceX will hand over time-sensitive samples to NASA for delivery to science teams around the world.

The Dragon’s splashdown will end SpaceX’s fourth commercial resupply flight to the space station, which began with a middle-of-the-night launch Sept. 21 aboard a Falcon 9 rocket from Cape Canaveral.

SpaceX’s next cargo mission to the orbiting research lab is set for launch around Dec. 9.

Orbital Sciences, NASA’s other cargo transportation provider, is preparing its third operational mission to the space station for liftoff as soon as Oct. 27.