A late SWITCH to a new rocket fuel earlier this year may have slowed Virgin Galactic’s bid to establish the world’s first suborbital spaceline service, but the operator’s plans have not stalled, nor has it been standing still.
Eager to show progress with engine TESTS and new spaceship construction, Virgin’s efforts partly temper the evident frustration expressed by many who gathered here to mark the 10th anniversary of the X-Prize FLIGHTS of SpaceShipOne in 2004. The FLIGHTS won the $10 million Ansari X-Prize for Mojave Aerospace Ventures, a joint venture of Scaled Composites and Microsoft co-founder Paul Allen, and led directly to the establishment of Virgin Galactic and the development of the much larger SpaceShipTwo (SS2). The achievement ushered in the beginnings of what is still hoped to be a new era of affordable private suborbital space travel, but these goals remain unfulfilled a decade later.
While officials at Virgin Galactic are among the first to admit that the opening up of this new frontier has taken perhaps much longer than anyone expected in 2004, the company insists it is finally on the verge of full-duration powered test flights and the start of commercial suborbital flights in 2015. Providing a rare glimpse of progress on a second spacecraft under assembly at sister organization, The Spaceship Co., Virgin Galactic Vice President of Operations Mike Moses says, “we are ready for space.” A former NASA launch integration manager for the space shuttle, Moses adds that SS2 “has been in modification, getting retrofitted ready to resume powered flights.” He notes that “those are going to start imminently—literally very imminently.”
Commenting on the extensive gap between now and the last rocket flight in January, Moses says, “It might seem a long time since our last powered flight-TESTING and that maybe nothing has been happening, but [ground testing] has been happening.” Tests have largely focused on ground-firings of a HYBRID rocket motor fueled with polyamide-based plastic in place of the hydroxyl-terminated polybutadiene, a form of rubber used for the first SERIES of powered tests. Although this fuel had been used successfully in SpaceShipOne, the vehicle developer Scaled Composites and Virgin Galactic encountered fuel-burn stability and power issues as they tried to scale the Sierra Nevada Corp.-provided hybrid motor up to the size required by the larger SS2.
Virgin announced the switch to the new fuel in May, and CEO George T. Whitesides says tests have been positive, with firings now focused on demonstrating repeatable, predictable ignition and steady fuel burn. Trials have been conducted on two stands here, one of which is a vertical TEST unit with a large oxidizer tank and the other a portable device that replicates the flight tank, hardware and plumbing of the SS2. “We are doing a series of qualification firings versus development firings . . . and we have one more formal qualification in the program for the plastic [fuel],” Whitesides says. If this goes WELLand replicates performance in recent tests, the rocket will be cleared to restart powered flight tests.
In the run-up to the final series of powered tests, Scaled conducted another glide flight of the SS2 on Oct. 7 that included an activation of the tail feathering mechanism. The official transfer of the SS2 from Scaled to Virgin will take place upon completion of key contractual milestones, Whitesides says. Although the main intention remains to demonstrate a fully powered suborbital flight with an apogee beyond the 100-km (62-mi.) “Von Karman” altitude limit that defines the boundary between the atmosphere and space, Virgin will be satisfied with two main criteria: “We’d like at a minimum for [Sealed] to demonstrate supersonic reentry and peak heating, if we can,” Whitesides says.
“What we are trying to do is balance two things,” he adds. “Scaled Composites’ contractual responsibility is to demonstrate the spaceship can achieve the requirements we set out at the beginning of the program. At the same time, we want to get into commercial service as quickly as we can, and the best way to do that is to basically do as much of it as we can as quickly as we can.” The company therefore plans over the next few TEST FLIGHTS to “evaluate a few things,” Whitesides says.
These will include the readiness of Virgin Galactic’s operator’s license from the FAA, the technical progress of the actual TEST flights and the readiness of the spaceline’s own crews. “We think we’re in really good shape in that area now. We did a 4.5-hr. flight of the carrier aircraft this week and had no squawks at all,” he adds, referring to the high standard to which the Virgin Galactic team now operates the formerly Scaled-flown WhiteKnightTwo (WK2) carrier aircraft. “We are less tied up in the number of flights and more [involved] in Scaled demonstrating those technical milestones. Then we will be at a point where [Scaled President] Kevin Mickey and I will discuss when to make that switchover,” Whitesides notes.
Gaining the operator’s license is largely a question of timing, according to Whitesides. “We made our original application in the summer of 2013 and the clock started once we hit the ‘sufficiently complete’ milestone in August 2013,” he says. “That’s the point at which the FAA’s 180-day [review period] started.” As it became clear that more test and development work was required, Virgin requested a voluntary toll “a short number of days before the 180 days expired,” he adds.
TESTING meanwhile continues under Scaled’s experimental permit until Scaled and Virgin are ready to transition operations. “So what will happen is when Scaled and we, and frankly the FAA, feel like we are ready for this big transfer, we will request the toll be removed. Then the FAA will make a determination within the timeline, which is now less than a month.”
Following the latest glide flights, SS2 is expected to be fitted with the modified rocket MOTOR and flown for a series of final test flights to complete the development effort. “We are close to taking the spaceship from Scaled, which will mark the close of the development program. Then we will be off to the races,” Whitesides says. Virgin Galactic may conduct “one or two more test flights here [at Mojave] and then one or two in New Mexico [at Spaceport America, near Las Cruces], or maybe more,” he adds. “We will see what is required and then go into commercial service.” While the company declines to forecast when this may be, Virgin founder Richard Branson said in a recent televised interview that commercial flights could start next February or March.
Production of the second SS2 is well advanced inside the Mohave assembly facility operated by wholly owned Virgin subsidiary The Spaceship Company (TSC). The MANUFACTURING arm is a sister company to the Virgin Galactic operations group and was set up to make production versions of the SS2 and WK2 vehicles. “Today VIRTUALLY the whole outside shape of the vehicle and most of the internal structure is done. We have landing gear hanging underneath it,” says TSC President Doug Shane. The 68,000-sq-ft. final assembly integration and test hangar (Faith) building houses lay-up production jigs for the one-piece composite spars and wing skins for WK2 and SS2, as well as tools for producing fuselages.
“The plan is to have the second SS2 on its wheels by end of the year,” says TSC Operations Vice President Enrico Palermo. “It is an aggressive goal, but we are pushing the team toward that. We are taking it to FLIGHT tests next year and will then deliver it to Virgin Galactic in 2016. To have a spaceline, you need a fleet of spaceships, and that’s where TSC comes in.”
Compared to the first spacecraft, Serial No. 2 will have “the same outer mold line but incremental improvements,” Palermo adds. “We have taken lessons learned from when Scaled built the first vehicle and used those to optimize the structure and systems.” Shane notes that TSC is “doing a better job of controlling all the things you can control in a manufacturing operation to tighten tolerances and keep the weight down—we are taking advantage of the smart stuff.”
TSC will resume assembly of the second WK2 in 2015 once the second SS2 starts FLIGHT tests. As with the spaceship, the carrier aircraft will benefit from the experience gained during development of the initial WK2. The second aircraft will, however, be capable of greater payloads to handle the Launcher One air-launched orbital liquid-fueled rocket Virgin is developing. “Satellite launch is a very important part of the program and the second WhiteKnight will be able to lift a bit more weight,” says Branson. The current WK2 has a maximum take-off weight of 65,000 lb. and design payload is around 35,000 lb. The first wing skins and ribs for the 141-ft. span aircraft have been built and “we are starting to work on the spars,” adds Palermo.
Quelle: Aviation Week