WASHINGTON — Space Exploration Technologies Corp. () expects to have another Falcon 1 rocket on the launch pad within weeks of a disappointing third flight attempt Aug. 2, which ended in failure when the rocket’s first stage re-contacted the second stage after separation.
The Hawthorne, Calif.-based rocket start-up says avoiding a repeat of that scenario should be as easy as inserting an extra couple of seconds between main engine cut off and stage separation.
“We have quite a definitive understanding of what went wrong on the last flight,” SpaceX Chief Executive Elon Musk told reporters in an Aug. 6 teleconference. “If we were to increase that gap by even a second or two, this problem would not have arisen.”
launched its third Falcon 1 around 11:30 p.m. EDT from the U.S. Army’s Reagan Missile Test Site on Omelek Island in the Kwajalein Atoll, which sits about 4,000 kilometers southwest of Hawaii in the central Pacific Ocean.
Video released by the company Aug. 6 shows that the rocket’s first and second stages separated as planned about 2 minutes and 20 seconds into the flight. However, unanticipated residual thrust from the recently redesigned Merlin 1C main engine caused the first stage to fly into the second stage just as the latter began to fire.
Both halves of the rocket fell into the ocean well east of the U.S. Marshall Islands, along with a payload that included the Pentagon’s Trailblazer demonstration satellite and two tiny NASA satellites mounted on an adapter ring being tested for Malaysia’s Astronautic Technology (M) Sdn. Bhd. (ATSB) in preparation for a Falcon launch of its RazakSat remote sensing satellite. Also lost were the cremated remains of more than 200 people, including those of NASA astronaut Gordon Cooper and actor James Doohan of “Star Trek” fame.
The Aug. 2 launch marked the first flight of SpaceX’s Merlin 1C engine, which uses a regenerative cooling system that circulates propellant through a series of channels along the thrust nozzle before sending it to the combustion chamber for ignition. Previous Merlin engines used ablative cooling systems that burned away material to shed excess heat. SpaceX learned the hard way that the new engine takes longer to cease producing thrust after the command is given than its predecessor.
Musk said the residual thrust issue was not discovered during testing because the chamber pressure inside the engine once it shuts down is so low – about 10 pounds per square inch – that it is masked by the ambient pressure of 14.5 pounds per square inch that the engine operates in on the company’s ground test stand in Texas. However, in a near-vacuum at such a high altitude, that residual thrust was enough to cause the first stage to re-contact the second stage.
Musk said that in contrast to the second Falcon 1 flight – which did not make orbit due to a premature second-stage shutdown – the Aug. 2 flight had only one issue that needs to be worked before the next launch. As a result, Musk said, the next Falcon 1 would ship out for Omelek Island before the end of August with an eye toward launching in September pending range availability.
“If we had a rocket on the launch pad tomorrow we could make this timing change, launch and be okay,” he said.
But since Malaysia’s ATSB – whose RazakSat satellite is next in line on the Falcon 1 manifest – wants to see at least one successful launch before entrusting the vehicle with its payload, SpaceX is approaching flight four as a demonstration. Although he did not rule out having a paying customer aboard the next flight, Musk said SpaceX previously promised ATSB, which is wholly owned by Malaysia’s Ministry of Finance, that it would prove Falcon 1’s ability to reach orbit before launching RazakSat.
Musk also said he does not intend to launch the larger, more expensive Falcon 9 before Falcon 1 proves itself. The first Falcon 9 is slated to arrive at Florida’s Cape Canaveral Air Force Station before the end of the year in preparation for a demonstration launch for a U.S. government customer SpaceX is forbidden to identify.
“I wouldn’t feel comfortable launching Falcon 9 until we got at least one Falcon 1 to orbit,” he said.
has four other Falcon 9 launches on its manifest for 2009, including two demonstration flights under NASA’s Commercial Orbital Transportation Services (COTS) program, which is pumping $278 million into SpaceX’s effort to demonstrate a cargo delivery system for the international space station.
Doug Cooke, NASA deputy associate administrator for exploration systems – the NASA directorate funding COTS – told reporters Aug. 5 that while the agency certainly had been hoping for a success Aug. 2, it has not lost faith in SpaceX.
“We obviously wish it had gone better. This is a tough business,” Cooke said. “We all have to get through test failures and things like that. I’m sure they’ll learn from it.”
Three days before the Aug. 2 launch, SpaceX conducted its first firing of the nine engines that comprise the Falcon 9’s first stage at its Texas test facility near McGregor. “The nine-engine firing is a big deal,” Cooke said, noting that SpaceX completed it about two months ahead of the schedule spelled out in its COTS agreement. Assuming NASA signs off on the results, the engine test will earn SpaceX a $22 million payday from NASA, bringing the company’s total COTS payments earned to date of just under $200 million.
Meanwhile, SpaceX announced following the Aug. 2 launch that it had accepted a $20 million investment the previous week from Founders Fund, a San Francisco-based venture capital firm managed by three of Musk’s former PayPal co-founders.
Musk said SpaceX remains cash flow positive with enough capital on hand for at least three more flights. “I suspect we won’t actually use the $20 million,” he said. “It’s only there for a worst-case scenario.”
Musk also made clear that he is ready to endure more setbacks if that is what it takes to ultimately field the safe, reliable and low-cost rockets he pledged six years ago to bring to the market.
“I’ve never given up and I’ve never lost,” Musk said. “And I’m not going to start now.”
Malik contributed to this story from New York.