The Wall Street Journal
By Andy Pasztor
Nov. 12, 2014 7:22 p.m. ET
Long before the recent fatal crash of Virgin Galactic LLC’s rocket ship, the craft’s progress had been plagued by technical problems that few outsiders knew about, according to engineers and a former government official involved with the project.
Engineers and subcontractors working on SpaceShipTwo spent years wrestling with difficulties, ranging from inadequate rocket-motor thrust to problems in the flight-control system to structural deficiencies affecting the wings of the rocket’s carrier plane. Fixes were devised, flight tests were delayed and the result, these people said, was that some important elements of the project remained in flux for several years. Without a firm design, there was no way to reliably predict when the first passengers would make it to space for more than $200,000 a ticket.
It isn’t unusual for complex vehicles such as spacecraft and airliners to face repeated pitfalls and delays during development.
Yet throughout the process, Virgin Galactic founder Richard Branson repeatedly announced timetables that were more aggressive than technical advances warranted, the people said.
“It is normal for new air vehicles to undergo modifications during their design” and testing, Virgin Galactic said in a written statement this week. That process is “the very thing that improves their safety before paying customers fly on them,” it said.
Federal investigators probing the Oct. 31 crash, which killed one of the two pilots, believe a cockpit error started the catastrophic chain of events. The investigation is continuing.
The National Transportation Safety Board also is delving into internal company dynamics. “Was there pressure to do testing?” acting Chairman Christopher Hart said to reporters days after the accident. “Was there a problem with the training?”
Over the years, Mr. Branson used sweeping terms to describe his space-tourism company’s goals. The Associated Press in 2009 quoted him saying, “We’re literally hoping to send thousands of people into space over the next couple of years.”
Michael Moses, head of operations for Virgin Galactic, referred to tension between Mr. Branson’s upbeat projections and the persistent hurdles that challenged the company’s hundreds of technical experts. “There’s a difference between the marketing and the engineering” sides of the company, Mr. Moses said 10 days after the accident.
Mr. Branson—who repeatedly said he would take the first thrill ride himself, accompanied by family members—represented the ultimate “impatient customer, saying I want to fly by Christmas” or some other date, Mr. Moses said.
He said, however, that the company gave serious attention to traumatic events such as the recent crash. “Nobody would say you don’t have to fix anything,” in the wake of such a catastrophe, Mr. Moses said. Virgin Galactic is re-evaluating past engineering trade-offs “to make sure we’re still comfortable with them,” he added. Mr. Moses said management didn’t cut corners on safety or conducting flight tests.
Other people familiar with the details contend that Virgin Galactic and its main contractor didn’t adequately address some problems that arose. A former senior troubleshooter on the project worried that fuel seepage into the carbon-fiber core material of the center wing section of the carrier plane from which SpaceShipTwo is launched threatened to compromise its strength.
Mr. Moses said engineers added extra material to the plane’s wings to ensure that they would flex safely. They also changed the design of some of the rocket ship’s tail surfaces in the wake of an aerodynamic stall and unusually steep descent during a test flight, another Virgin Galactic executive said.
According to a senior engineer familiar with the project, high-ranking managers at Virgin Galactic failed to adequately heed warnings about chronic propulsion shortcomings that resulted in extensive delays and eventually forced Virgin Galactic to revamp its rocket motor and switch to a new fuel.
The engineer and a former government official recalled that engineers felt schedule decisions were announced with scant input from them. “Management’s attitude was simply we know best,” the official said.
Virgin Galactic said the company and its contractors “have internal milestones, such as schedule estimates and goals, but the companies are driven by safety and the completion of the flight test program before moving into commercial service.” Virgin Galactic’s schedules have always been consistent with internal schedules of its contractors and changes have “never impacted flight safety,” the company said in a written statement.
In more than seven years of development, SpaceShipTwo’s motor had been fired in flight only three times before last month’s crash—and never for longer than 20 seconds. Planned commercial flights to the edge of space 62 miles up are expected to require roughly a 60-second engine burn.
Seeds for technical turmoil were planted nearly a decade ago when the company that developed the original rocket motor had a falling-out with renowned aerospace designer Burt Rutan, who conceived the idea of launching a rocket ship from an airplane at 50,000 feet and was the driving force behind SpaceShipTwo. The dispute had to do with who deserved credit for developing the original rocket motor. The upshot was that Mr. Rutan’s company, Scaled Composites LLC, took over the job of building the motor, but troubles persisted.
It wasn’t until 2009, following a ground test that killed three of its employees, that Scaled Composites acknowledged needing help, according to the engineer familiar with the project. With Virgin Galactic’s approval, Scaled Composites recruited specialty engine maker Sierra Nevada Corp. to take over all engine work. Scaled Composites is now a unit of Northrop Grumman Corp. , which declined to comment. Shortly after the fatal explosion, Mr. Rutan said the company believed that the manner it which it conducted the test “was completely safe.”
When Sierra signed on in 2009, the company said it would take between four and six years to properly finish the job, the engineer said. Virgin Galactic still had “essentially a hole in the middle of the craft where the engine should have been” in the fall of 2010, the person recalled.
Nonetheless, Mr. Branson around the same time was quoted in newspapers saying that his own trip would happen in 18 to 24 months. That would have put him on board at the latest by the fall of 2012.
In 2012 and 2013, despite continuing performance problems with the engine, which burned a rubber compound combined with an oxidizer, the engineer recalled, Virgin Galactic kept saying Mr. Branson’s flight was less than a year away.
By the spring of this year, with Mr. Branson’s flight as the first passenger supposedly happening by year-end, the company changed course. Nagging vibrations were “very distressing to pilots because they simply couldn’t read their instruments,” the former government official said.
Also, the motor didn’t have enough power to blast the proposed 60-foot spaceship, six passengers and a crew of two to the required altitude. Sierra blamed Virgin Galactic for making SpaceShipTwo overweight and urged a temporary compromise to take up fewer passengers, according to the engineer familiar with the project.
Virgin Galactic responded it couldn’t make money under such circumstances, the person said. The partners responded by parting ways on engine development, and Virgin Galactic engineers switched to a new plastic-based fuel intended to boost the rocket’s power.
Mr. Moses, Virgin Galactic’s head of operations, said development was complicated by the fact that “we didn’t know exactly what the final weight and thrust would be.”
When Virgin Galactic’s own engineers conducted the fifth ground test of the reformulated, plastic-based fuel, earlier this year, an explosion all but obliterated the test stand, two people familiar with the test said. Virgin Galactic President George Whitesides this month said the test was intended to demonstrate how the motor would perform under extreme conditions: specifically, the company drilled holes on the outside, apparently to simulate an in-flight rupture.
But the two people knowledgeable about the test disputed that the explosion was part of a plan. “No company would purposely destroy its own testing facility the first time it tried a new fuel,” one of the people said.
Virgin Galactic responded in a written statement that “we knew failure was a potential outcome.”
Recently, Mr. Branson has said he might now steer clear of schedule pronouncements. “I have given dates in the past and not met them,” Mr. Branson told ITV News this month. “I don’t want to give the skeptics about our program any extra ammunition.”
—Jon Ostrower contributed to this article.
- Source: http://online.wsj.com
Subscribe to:
Post Comments (Atom)
No comments:
Post a Comment