WASHINGTON — Space Exploration Technologies (SpaceX) Corp.’s Falcon 9 rocket soared into orbit in its June 4 debut lofting a prototype cargo capsule and boosting the hopes of NASA’s controversial commercial spaceflight initiative.

After months of delay, a prolonged countdown and a last-second launch abort, the two-stage liquid oxygen- and kerosene-fueled rocket lifted off from Cape Canaveral Air Force Station, Fla., at 2:45 p.m. EDT. Only 1 hour and 15 minutes earlier, the launch was halted just before the countdown clock hit zero. A SpaceX launch commentator attributed the abort to an “out-of-limit start-up parameter.”

Prior to the abort, the launch countdown was held at T-minus 15 minutes for about two hours while the SpaceX flight team and range safety officials evaluated a low signal reading from one of the antennas on the Falcon 9’s flight termination system. Boats straying into the keep-out zone surrounding the coastal launch complex presented another nuisance to be dealt with prior to resuming the first countdown at 1:15 p.m.

Thousands of people tuned in to SpaceX’s glitch-prone webcast to watch the launch and kept tabs on the preparations throughout the day via Twitter, the microblogging website. As it became clear that SpaceX had defied critics by reaching orbit with the Falcon 9 on its first try, the plaudits quickly poured in.

“Congrats to SpaceX on a great first flight for the Falcon 9!” tweeted NASA Deputy Administrator Lori Garver.

William Pomerantz, senior director of space projects at the X Prize Foundation, let it be known that he was going to celebrate by having a beer with lunch. “I feel like I earned it, just by watching, wishing, and believing,” he tweeted.

Brett Alexander, president of the Commercial Space Flight Federation — a Washington group that counts SpaceX among its members — called the day “historic.”

“The Falcon 9 rocket rising into the sky was carrying the hopes and dreams of the hundreds of engineers who worked on this new project,” Alexander said in an e-mail to Space News. “And I know that thousands of well-wishers across the country were cheering that rocket on. For a brand-new rocket to accomplish this much on its first mission is truly impressive, given the historical track record of new vehicles.”

That enthusiasm at SpaceX’s success was not universally shared, however.

U.S. Sen. Kay Bailey Hutchison (R-Texas), a critic of President Barack Obama’s plan to rely on companies like SpaceX to ferry cargo and astronauts to the international space station, tempered her mild praise with a dose of complaint, calling the launch “a belated sign that efforts to develop modest commercial capabilities are showing some promising signs.”

“Make no mistake, even this modest success is more than a year behind schedule, and the project deadlines of other private space companies continue to slip as well,” she said in a statement.

NASA Administrator Charles Bolden, in a written statement, said the Falcon 9’s successful debut was “an important milestone in the commercial space transportation effort and puts the company closer to providing cargo services to the International Space Station.

“This launch of the Falcon 9 gives us even more confidence that a resupply vehicle will be available after the space shuttle fleet is retired.”

Although the rocket carried a prototype of the Dragon cargo capsule on its debut, the June 4 flight does not count as one of the three demonstrations the company agreed in 2006 to conduct under NASA’s Commercial Orbital Transportation Services (COTS) program. SpaceX won a $1.6 billion contract in 2008 to deliver cargo to the international space station using the Falcon 9 and Dragon.

SpaceX officials said prior to the launch that they were targeting July for the first COTS demonstration flight. The Dragon built for that mission is expected to spend five hours in space, completing several orbits before returning to Earth. The second COTS demo is targeted for March 2011. SpaceX hopes to send that flight to the space station, rather than perform the fly-by originally proposed, but NASA has to approve the change of plans.


A Long Wait

When SpaceX delivered the Falcon 9 hardware to the launch pad late last year, the company expected to launch between March and May. But U.S. Air Force concerns about the flight termination system, which uses explosives to destroy the rocket in the event that it veers off course, continued to hold up the rocket’s maiden flight.

During a June 3 teleconference with reporters, SpaceX founder and chief executive Elon Musk said the Air Force had signed off on the Falcon 9 flight termination system (FTS) earlier that day.

“It’s a pretty intense testing process for the flight termination system. Obviously they want to make sure it works even under extreme circumstances,” Musk said. “There were some elements of it that we underestimated, some elements that our suppliers underestimated completing the development of the FTS system.”

Prior to launch, Musk likened the odds of a successful first launch to surviving a game of Russian roulette.

“I think my personal assessment of the likelihood of success is probably 70 to 80 percent,” he said. “However … that is less than the probability of success in Russian roulette.”

SpaceX said in 2005 that it had sold Falcon 9’s inaugural launch to a U.S. government customer it was not permitted to name, prompting speculation that the customer is an intelligence agency since the U.S. Air Force publicly announces launch contracts even when the payloads are classified.

Falcon 9’s debut was supposed to have happened in 2007, but development of the rocket and its smaller sibling, the Falcon 1, took longer than planned.

In March, SpaceX aborted the Falcon 9’s first static-fire test just as the rocket’s nine engines were about to ignite for a planned 3.5-second burn. SpaceX officials said the test automatically aborted at T-minus 2 seconds when the rocket’s turbo machinery failed to commence spin start because a pressure valve that should have been commanded to open remained closed.

Six days earlier, SpaceX completed what the company described as a flawless countdown-and-propellant-loading exercise known in rocketry circles as a wet dress rehearsal.