The third time may be a charm, but even if it is not SpaceX's founder says he is committed to the launch business and now regrets having said two years ago that he probably would have only three chances to launch his Falcon 1 rocket successfully.

In the run up to the Falcon 1 rocket's 2006 maiden flight, Elon Musk, founder and president of Space Exploration Technologies (SpaceX), said he would be inclined to call it quits if he could not pull off a successful launch within three tries.

On that first flight, the Falcon 1's main engine caught fire and failed 29 seconds after liftoff, leading to the loss of the vehicle and payload, a small experimental satellite built by U.S. Air Force Academy cadets.

A year later, a second Falcon 1 was back on the pad, ready to try again, this time without a satellite on board. After an encouraging liftoff that saw the privately-financed Falcon 1 reach space for the first time, a control issue caused the rocket's kerosene-fueled main engine to shut down about 90 seconds too soon. Once again, the $6-million Falcon 1 had failed to achieve orbit.

With a third Falcon 1 launch attempt fast approaching, the 36-year-old serial entrepreneur is distancing himself from his three-and-out remark and assuring customers and his 470 employees that he is in the launch game for the long haul.

"I made a stupid comment once," Musk told reporters during a May 14 lunch here sponsored by the Space Foundation. "I was asked, 'how many failures can you withstand?' I said, 'well, if we had three failures in a row, then I suspect we would not get any customers, and then it wouldn't make sense to continue.' I was partially quoted thereafter saying, 'three failures and we're out.' That's actually not the full statement. The full statement was if our customers abandon us, then we are out."

Six years have passed since Musk started SpaceX to bring about the cheaper launches he sees as a necessary precondition for humanity fulfilling its potential as a truly spacefaring civilization. Although fielding a reliable, low-cost launcher is taking longer than he once hoped, Musk said he is not about to throw in the towel.

"We are in this for the long term," Musk said. "SpaceX will never give up. I will never give up. Never."

With a backlog of 12 launches on the manifest through 2011 and a newly inked launch services agreement with NASA potentially worth $1 billion, the Hawthorne, Calif.-based company actually managed to add new customers to its roster since the March 2007 launch attempt left the Falcon 1 with an 0-2 record.

Musk, however, makes the case that the Falcon 1's record should be amended to 1-1, or at least carry some sort of asterisk noting that the second launch was a confidence-boosting success "from a test standpoint" even if the rocket did not reach orbit.

"Given that after our last launch we signed up several new customers, I think it's safe to say that we can count that last launch as a success in the eyes of our customers which is really where it counts," he said.

And nothing gets Musk's back up like characterizing Falcon's second flight as a launch failure.

"One of the things that was very annoying was how the flight was described by some people in the media, frankly, who seem to be sort of 'the glass is one-tenth empty.' You know? I mean really," he said.

However, Musk later volunteered that launching satellites, unlike designing software or building electric cars — two other endeavors he knows well — is an unforgiving business.

Once the rocket leaves the pad, no amount of software updates or mechanical recalls will give the customer a working satellite if it fails to reach orbit safely.

"You have to get everything right," he said. "The passing grade is 100 percent."

Musk made clear that he will hold Falcon 1 to the unforgiving pass-or-fail grading criteria during its upcoming launch for the Pentagon's Operationally Responsive Space (ORS) program office, calling the planned late-June mission an "operational flight" as opposed to a test.

The payload for the mission has not been assigned, although a senior ORS official said in late April that the U.S. Air Force Research Laboratory's Plug and Play satellite is the top candidate for the mission, dubbed Jumpstart. Should Plug and Play not be ready to go in time, the official said, SpaceX will be asked to launch either the Trailblazer satellite, built by SpaceDev Inc., or CUSat, which was developed under a partnership between the Air Force and Cornell University.

SpaceX, for its part, will not be informed of the Pentagon's payload selection until two weeks before launch, which Musk said is targeted for "approximately the last week of June."

He said the rocket's first stage is already in place at the company's private island launch complex in the Kwajalein Atoll, with the second stage to join it there in a "couple of weeks."

Musk refused to be pinned down on a precise launch date, however, telling reporters SpaceX would take all the time it needs to get it right.

"At the end of the day we are not going to rush this flight," he said.

It also is clear SpaceX is not counting on the old adage "third time's the charm" to ensure a successful launch. Musk put the odds of a successful next flight at "85 to 90 percent."