In a refurbished Air Force hangar at Cape Canaveral, engineers from NASA and commercial space company SpaceX on Tuesday pored over data from a launchpad test of a gleaming white rocket poised to be the next step in U.S. space strategy.

The review may be the final hurdle before a much-delayed and highly anticipated launch — the first attempt to send a privately designed and built unmanned spacecraft to the international space station.

What SpaceX and NASA hope to do is part of a plan begun under President George W. Bush and enhanced by President Obama to turn travel to and from the space station into a largely private and less costly venture, freeing up NASA to plan for deep-space journeys to asteroids, the moon and ultimately Mars.

“It’s proving to be harder and more complicated and more expensive than [SpaceX founder] Elon Musk anticipated,” said Dale Ketcham of the Spaceport Research and Policy Institute at Central Florida University. “But it’s still more efficient than NASA.”

The company and the space agency are “targeting” Monday for the launch, but more delays could crop up if the final data check turns up problems. “We’re going to check and double-check and triple-check before launch day,” said Kirstin Brost Grantham, a spokeswoman for SpaceX.

If all goes well, the flight will deliver 1,100 pounds of food, water and other cargo to the 16-nation outpost, a capability the United States gave up when it retired the space shuttle last year. (Cargo vehicles built by Russia, Europe and Japan now supply the six-person crew.) Even more crucially, a successful docking would mark a milestone for commercial space companies.

NASA and SpaceX officials are emphasizing the excitement of the mission while tamping down expectations, noting just how difficult it will be to dock a new spacecraft to the space station. Many systems on the unmanned Dragon capsule, including its solar panels and the hardware and software needed to dock with the station, are being flown for the first time.

“This is a really tough flight,” William H. Gerstenmaier, NASA’s top official for human spaceflight, said during a recent news briefing. “What we’re asking them to do is amazing.”

The launch was originally designed as a fly-by of the station in which the Dragon would demonstrate it could approach, navigate with precision, “free-drift,” hold nearby and abort if necessary.

But last year SpaceX and Musk asked NASA for permission to try an actual docking. NASA’s Commercial Orbital Transportation Services program manager, Alan Lindenmoyer, said that after a safety review, the agency decided to allow an attempted docking if the other maneuvers succeed.

The docking, if it occurs, will be on the third day of the flight, and the Dragon capsule will stay attached to the station for up to 18 days.

Although the craft will carry cargo, Musk said the effort remains “explicitly a test flight. Indeed, we may not succeed in getting all the way to the space station.” Later he said, “A lot can go wrong with a mission like this.”

SpaceX employees will control the capsule through docking, Musk said, although astronauts on the station also have an emergency abort switch. NASA Mission Control in Houston will also make a number of “go” or “no go” decisions as the spacecraft nears the station.

If the capsule is allowed to attempt a docking, astronauts on the station will grab it with a 57-foot robotic arm that will pull the capsule to the docking port.

The launch has been delayed several times. SpaceX engineers have struggled to ensure that electronics in the Dragon capsule do not interfere with the space station’s systems. In late April, the company pushed the launch back another week to run more computer simulations of the docking. Monday’s launchpad test was delayed by an hour by a computer glitch.

Still, SpaceX is ahead of other private space companies. It has already successfully launched one Dragon capsule that orbited Earth and landed safely on target, in the Pacific Ocean, in December 2010. A NASA analysis published last year found that SpaceX developed its Falcon rocket for about a third of what NASA would have spent.

Orbital Sciences of Dulles is the other U.S. company with a NASA contract to deliver cargo to the station. That company has scheduled the first launch of its Antares rocket and cargo carrier from Wallops Island, Va., late this summer.

Private contractors have built rockets for NASA in the past, of course, but the new companies have been given much freer rein to design and operate their vehicles under fixed-price contracts.

The SpaceX venture is especially significant because its capsule — unlike any other cargo carriers under production or available from other nations — was designed to return to Earth rather than break up in the atmosphere. That would allow scientists to have their experiments returned, another capability the United States gave up when it retired the shuttle. (The Russian craft that now ferry astronauts to and from the space station return only crew members, not cargo.)

A successful flight would also aid SpaceX in its race to become the first commercial company chosen by NASA to carry astronauts to and from the station. SpaceX is competing with space stalwart Boeing and two newer companies, Sierra Nevada and Blue Origin (founded by Amazon chief executive Jeff Bezos), for NASA contracts to carry crew.

Space experts are watching the launch carefully for indications of how far commercial space has come, but they do not necessarily expect the capsule to dock.

“If Dragon fails at launch, that’s a bad thing that will get people concerned,” said John Logsdon, professor emeritus at the Space Policy Institute at George Washington University.

“But if it gets close but can’t dock, I would say that’s a setback but not a tragedy,” he added. “If they’re able to get close or even dock, then it would do quite a bit for commercial space — a real validation for those in NASA who set this in motion.”

While that view is common among officials involved in the effort, it is not necessarily the view of the SpaceX employees trying to make it work.

Encountered at dinnertime at a restaurant near the SpaceX hangar at Cape Canaveral earlier this year, four SpaceX engineers were preparing to return for a second shift. When asked what would make this mission a success, one engineer said that “there’s only one definition” — getting to the space station and docking.

Musk, who also founded the company that makes Tesla electric cars, has a contract with NASA to fly 12 cargo missions to the space station for a total of $1.6 billion. The contract can be extended to a value of $3.1 billion if the early supply flights are successful.

SpaceX, which is based in Hawthorne, Calif., and employs 1,700 people, is eying a second unused Air Force hangar at Cape Canaveral so it can ready two rockets simultaneously. It also may rent one of NASA’s two now-unused space shuttle launchpads and is discussing plans for a launch facility in Texas.

Meanwhile, Musk regularly makes waves by limning much grander dreams. This year, he talked of sending people to Mars for $500,000 a pop — the cost today of hoisting 6 or 7 gallons of water into low Earth orbit. The company’s Web site is filled with videos of huge rockets that will — someday — fly back to the launch site for near-instant refueling and relaunch. These reusable rockets do not yet exist, and Mars remains as distant as ever.

Before SpaceX heads for the Red Planet, it has many hugely challenging and more immediate concerns — building and launching 40 rockets over the next five years to fulfill contracts worth $4 billion.

In addition to carrying out the 12 space station resupply missions, the company has contracts to launch satellites for Canada, Thailand, Taiwan, Israel and Argentina.

It is also working to grab a share of the Defense Department satellite launch business away from the consortium of aerospace heavyweights Lockheed Martin and Boeing called the United Launch Alliance.

In recent years, both Russia and China have launched more rockets with satellites or capsules than the United States, and American space prowess has been questioned — especially in Congress. Musk said recently that one of his goals is to help make the United States the top nation for space launches again, although with a twist.

“It would be historically significant if Dragon were to become the first commercial spacecraft to conduct a docking,” he said in an e-mail. “By commercial, I mean a design that was conceived of and brought into being primarily by a private company, rather than a nation.”