A 300-foot-long barge will be used as an off-shore landing platform during launch of a SpaceX Falcon 9 rocket Friday. The primary goal of the flight is to deliver critical supplies and equipment to the space station, but SpaceX hopes to land the rocket's first stage on the barge for possible refurbishment and reuse -- a key milestone in the company's push to reduce launch costs. Harwood/CBS News

SpaceX engineers are gearing up to launch a Dragon cargo ship atop a Falcon 9 rocket Friday for the company's fifth operational space station resupply mission. And if all goes well, the Falcon 9's first stage will attempt to land on a barge stationed off the coast of Jacksonville, Fla., a key milestone in SpaceX founder Elon Musk's drive to lower costs by reusing boosters that otherwise would be discarded in the sea.

The Marmac 300, a platform barge listed on McDonough Marine Service's website and modified for use by SpaceX, features a spacious deck measuring 300 feet long and 170 feet wide. The barge, which SpaceX calls an autonomous spaceport drone ship, was seen by reporters over the weekend docked adjacent to the Jacksonville cruise ship terminal.

"Reusability is the critical breakthrough needed in rocketry to take things to the next level," Musk said during the MIT AeroAstro Centennial Symposium in October. "We've been able to soft land the rocket booster in the ocean twice so far. Unfortunately, it sort of sat there for several seconds then tipped over and exploded (laughter). It's quite difficult to reuse. It's as tall as a 14-story building. When a 14-story building falls over, it's quite a belly flop!

"So what we need to do is be able to either land on a floating platform or ideally boost back to the launch site and land back at the launch site. But before we boost back to the launch site and try to land there, we need to show that we can land with precision over and over again, otherwise something bad could happen."

The SpaceX barge would appear to be an ideal offshore landing platform. The deck's dimensions are listed as 300 feet by 100 feet on McDonough Marine's website, but the barge was widened by two wing-like additions seen extending from its sides. Company officials did not return a phone call seeking additional information, but the barge is believed to be equipped with powerful thrusters capable of maintaining its position to within a few tens of feet and internal water tanks to help damp out wave action.

An industry source said the platform will be operated remotely or autonomously on launch day with a crew stationed on another ship a safe distance away.

The width of the Marmac 300 barge was extended to provide additional landing space for the Falcon 9 first stage, which has a leg span of some 70 feet. The dimensions of the landing platform are 300 feet by about 170 feet.

Harwood/CBS News

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SpaceX readies barge for off-shore rocket landing