The company is also developing a larger rocket, the Falcon 9, with nine engines in the first stage. That vehicle is intended to provide cargo services to the International Space Station under a contract for NASA after the shuttle program winds down in 2010. SpaceX performed a successful test firing of the Falcon 9 engines at its facilities in McGregor, Tex., last week.

Charles Lurio, an independent space consultant, it should not be surprising to lose single-use rocket vehicles in the early stages of development, because their very design does not allow test flights. "It's all or nothing once it leaves the pad," he said. "But I hope SpaceX keeps trying," he said. "They're very competent people."

In Mr. Musk's statement, he insisted that the company will not be deterred and still has strong support from its backers. "SpaceX will not skip a beat in execution going forward," he said, and added that the fourth flight, currently scheduled to take place in the fourth quarter of the year, and fifth flights are being prepared, and that he has given the go-ahead "to begin fabrication of flight 6."

And, he added, "We are in very good financial basis here. We have the resolve, we have the financial base, and we have the expertise" to identify the problem and go forward. "There should be no question about that." In a version of the statement distributed to employees, Mr. Musk said that the company "recently accepted a significant investment" that, along with the company's current cash reserves, will ensure that "we will have more than sufficient funding on hand to continue launching" the Falcon 1 and the larger Falcon 9 vehicles.

In the teleconference, Diane Murphy, the company spokeswoman, said that the mood at the company's headquarters quickly switched from excitement and cheers at the seemingly successful launch to concern and then disappointment. But when Mr. Musk addressed the employees, she said, and told them that the company would move forward with the fourth flight, "One of our employees immediately spoke up and said with great resolve, 'yes we will. We will get to orbit' — and everyone sent up a cheer."