CAPE CANAVERAL, Fla. (AP) — A private company is on the verge of launching another cargo ship to the International Space Station.
On Sunday night, California-based SpaceX will attempt to send a Dragon capsule to the orbiting lab and its three-member crew.
Liftoff of the company's unmanned Falcon rocket is scheduled for 8:35 p.m. EDT. Forecasters put the odds of acceptable weather at 60 percent. Thick clouds and rain are the main concerns.
A Dragon cargo ship successfully docked to the space station last May, but that was considered a test flight. The coming mission is the first under a $1.6 billion contract with NASA that calls for a dozen resupply flights by SpaceX, essential in the post-shuttle era.
"We got there once. We demonstrated we could do it, so there might be a teeny, teeny bit of relaxation. Not a lot, though," SpaceX President Gwynne Shotwell told reporters Saturday night.
NASA was monitoring a potentially threatening piece of orbiting junk, but said that even if the space station had to steer clear of the object, that would not delay the SpaceX mission.
This newest Dragon will haul about 1,000 pounds of food, clothes and gear, including ice cream for the American, Russian and Japanese astronauts on board. (The ice cream will go up in freezers meant for research). Even more cargo will be coming back.
The capsule will remain docked to the space station for most of October. Astronauts will fill the capsule with blood and urine samples, other experiments and old equipment, for its return to Earth at the end of the month. By then, the complex will be back to a full crew of six.
The nearly 500 tubes of blood and syringes of urine have been stashed in space station freezers since the last space shuttle flight, by Atlantis, in July 2011. The decommissioned Atlantis, and sister ships Discovery and Endeavour, are now museum relics.
NASA nutritionist Scott Smith said these blood and urine samples — part of medical studies — will be the first to be returned since Atlantis' final voyage.
"This is the first real return vehicle for this type of sample," Scott said.
The cargo ships periodically flown by Russia, Japan and Europe do not have the capability to return anything; they burn up upon re-entry. The SpaceX Dragons parachute down into the Pacific, reminiscent of NASA's old-time capsules.