The RM2's job is to propel SS2 and its two crew and six passengers or mission payload to altitudes over 100 km (62 mi.) with margin to spare. SS2 tests recommenced with a series of taxi tests at Mojave on June 1. Since ground and flight tests began, however, the propulsion system has become heavier than expected, resulting in an increase in operating empty weight over early assumptions. “For flight tests, this warranted looking at the overall capability of the landing gear,” says Siebold.

Unlike SS1, which was aimed at grabbing the X Prize, SS2 is designed to be a fully reusable transport. “We want a system that's robust,” Siebold stresses. “We therefore made changes to the wheels and brakes to get it closer to a production configuration.” On June 1, the spacecraft was towed behind a truck down the runway to conduct four tests of newer, higher-capacity brakes at 30-65 mph with four different pilots: Virgin Galactic chief pilot Dave MacKay and Scaled test pilots Siebold, Mike Alsbury and Clint Nichols.

Testing of the WK2 carrier aircraft has also accelerated since the aircraft resumed flights in April after a four-month spell on the ground. Much of the work so far this year has focused on the performance of a redesigned fuel inlet cooler and cycling of the gear at high altitudes after prolonged “cold-soaking.” “We've made some updates to the aircraft, and done some of those on the main landing gear,” says Shane.

Deployment of the gear at altitude is required to increase drag for faster descent. Issues with the gear have included sluggish deployment at high altitude and a partial collapse of the left main leg in August 2010. Overall, however, Shane classes the WK2 as being at a “high level of development.”

Flight-test lessons will be incorporated into production WK2s and SS2s, the first of which have now entered manufacturing at The Spaceship Company (TSC), the Mojave-based joint venture set up by Scaled and Virgin Galactic. Cabin halves, lower-wing skins and window surrounds for the next SS2 are built, while wing-skin panels for WK2 No. 2 have been laid in the 140-ft.-long wing jig in TSC's new $8 million final assembly, integration and test hangar site. Officially opened in September 2011, the 68,000-sq.-ft. facility is starting to fill up with structures and tooling. “This year is about parts fabrication and next year is for major assembly,” says TSC's vice president of operations, Enrico Palermo.

In the buildup to operations, Virgin Galactic's primary focus remains on passenger flights, despite a growing list of other applications including science, research and a potential small satellite launch. Although since its founding in 2004, the company has deliberately remained vague about the exact schedule for the start of services, the plan was believed to have aimed at beginning suborbital flights by or before 2011.

The extended schedule notwithstanding, the company continues to collect bookings for its flights at $200,000 per ticket. Virgin Galactic is expected to reveal a new tally at Farnborough this week with well in excess of 500 would-be space adventurers, and more than the total number of people ever to have traveled into space.

Preparations also continue for the start of commercial spaceflights from the purpose-developed Spaceport America facility near Las Cruces, N.M. As anchor tenant, Virgin Galactic is working with the FAA and local military airspace operators at White Sands Missile Range and Holloman AFB to “make sure we are a good neighbor,” says Whitesides. Virgin also recently held a team meeting with state authorities over ongoing work to extend the Spaceport's 10,000-ft. runway by a further 2,000 ft. “That's in the works and will be complete in time for our commercial schedule,” he adds.

The base of the highly unusual building is also nearing completion and should be finished over the summer. “The next phase will be Virgin Galactic coming in with contractors to do the requisite finish we think is required for our customers. In 2013, we will be outfitting the facility with equipment for ground support and more.”