Can SpaceX return booster to a barge? Third try Tuesday.

[Updated 5 p.m. EDT] Space Exploration Technologies Corp., which is slated to launch another cargo mission to the space station Tuesday afternoon, has shown it can ferry goods to and from the orbiting outpost successfully. Now it's trying to do something similar for spent rocket components – by attempting to return the first stage of its Falcon 9 rocket safely to a barge at sea.

Tuesday's attempt was scheduled after an approaching line of storms Monday came too close to Cape Canaveral Air Force Station, where the mission was to have launched at 4:33 p.m. Monday afternoon. Space Exploration Technologies Corp. (SpaceX) now plans to try for a 4:10 p.m. launch on Tuesday.

The effort represents the latest step in the company's bid to beat down the cost of launching payloads to space by developing a fully reusable rocket. If all goes well, for the first time in three tries, the booster will settle onto the barge for a soft landing, upright and intact.

From NASA's perspective, as well as that of SpaceX, which builds and operates the Falcon 9 rocket and its Dragon cargo capsule, the immediate goal is to deliver 2.2 tons of supplies to the space station. Those supplies include one espresso machine.

But the landing test carries its own import. If it works, "the implications are huge," said Hans Koenigsmann, the company's vice president of mission assurance, during a prelaunch briefing on Sunday.

In principle, fully reusable rockets could dramatically cut the cost of sending payloads into space. Spaceflight advocates have argued that dramatically cutting the cost of reaching Earth orbit could open near-Earth space to a host of commercial activities, from company or consortium R&D labs and manufacturing sites to orbiting resorts whose espresso cafes offer stunning views for more than a handful of government-employed astronauts.

The company's Falcon 9 already commands roughly $61 million for a commercial launch. SpaceX officials have said that a fully reusable rocket would cut the cost of a launch to between $5 million and $7 million.

That capability "would change how we approach transportation to space," Mr. Koenigsmann said. Operations would more closely resemble running an airline.

Building and operating a reusable spacecraft to reach Earth orbit proved hard enough when the craft had wings, like the space shuttle. The shuttle and its solid-fuel boosters were reusable. But the fuel tanks for the shuttle's main engines were new with every launch. And the shuttle's complexity, combined with periodic upgrades, never fully elevated the fleet above test-flight status.

SpaceX's approach has been to give the Falcon 9 the ability to spread four landing legs before touchdown as well as relatively small, paddle-like fins with open grids. The fins extend to steer the booster as it descends.

The first attempt to land on an autonomous barge came Jan. 10, during another space-station cargo mission. From SpaceX's perspective, the good news was that the booster reached the barge, validating the steering system. The bad news: The steering vanes used up the last of their hydraulic fluid just before touchdown. The booster slammed onto the barge's deck, skittered across it, and exploded.

Barge-landing test No. 2 came a month later, during the launch of the National Oceanic and Atmospheric Administration's Deep Space Climate Observatory, a new climate and space-weather monitoring satellite that the company successfully delivered to orbit.

SpaceX beefed up the hydraulic system controlling the vanes. But bad weather struck. Waves reportedly up to three stories tall crashed over the deck of the barge. This forced the company to move the vessel – newly christened Just Read the Instructions – out of the way.

Instead, the booster made a soft, vertical, controlled landing into the ocean within about 33 feet of its intended landing spot.

For Monday's expected launch, seas will be far calmer. Despite the accuracy of both landings and the extra hydraulic fluid to keep the steering vanes operating, Elon Musk, who heads SpaceX, says the likelihood of a successful landing Monday is less than 50 percent.

But if it works?

It would trigger "an epic landing party," Koenigsmann quipped.