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SpaceShipTwo test flight
SpaceShipTwo seen on its most recent unpowered test flight, on April 12; the contrail was produced by the “cold flow” of nitrous oxide propellant through its engine. A powered test flight could be as soon as Monday. (credit: Virgin Galactic/

Suborbital spaceflight powers up

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Today’s the day. Maybe.

After years of anticipation—and years of delays—Virgin Galactic’s SpaceShipTwo suborbital vehicle is widely expected to attempt its first powered flight on Monday. That flight is likely to involve a short burn of the vehicle’s hybrid rocket motor, enough to push the vehicle beyond Mach 1, but far short of what would be needed to fly into space. It would be similar to the first powered flight of SpaceShipOne, performed by Scaled Composites in December 2003, leading to the vehicle’s first full-fledged suborbital spaceflight the following June (see “SpaceShipOne makes history — barely”, The Space Review, June 24, 2004)

“We’re hoping to break the sound barrier. That’s planned Monday,” Branson said last week.

There’s been no formal announcement by Virgin Galactic that SpaceShipTwo will attempt a powered test flight Monday. But observers in and around Mojave Air and Space Port in California report preparations being made, and the airport has issued notices to airmen (NOTAMs) about access to the airport and surrounding airspace on Monday. Mojave-based space journalist Doug Messier reported Friday that access to the airport grounds themselves on Monday may be restricted to badged personnel, keeping out the press and the public.

“While many in the press and non-affiliate blogs are reporting an event in Mojave on Monday 29 April the Mojave Air & Space Port is not sponsoring a public or press related event,” read a statement on the front page of the airport’s website Sunday. “We cannot guarantee a date or time to monitor a test because tests occur when three critical items come together: the vehicle is ready, the weather can support and the test and airspace has been allocated.” (emphasis in original)

While neither Virgin Galactic nor the airport is talking, a senior—and not very anonymous—official is. “We’re hoping to break the sound barrier. That’s planned Monday,” said Sir Richard Branson, chairman of Virgin Galactic’s parent company, the Virgin Group, in an interview last week with the Las Vegas Sun. Branson was in Las Vegas in part to mark the latest milestone for another Virgin company, airline Virgin America, but said that after he finished business in Las Vegas “I’m going on to the Mojave Desert to be there for our first flight on our spaceship.”

“It will be a historic day. This is going to be Virgin Galactic’s year,” Branson continued. “We’ll break the sound barrier Monday and from there, we build up through the rest of the year, finally going into space near the end of the year.”

While Virgin may make a flight test of a crewed suborbital vehicle as soon as Monday, another company isn’t far behind. Just down the flightline from Virgin and Scaled at the Mojave airport, XCOR Aerospace is continuing work on its Lynx suborbital spaceplane, with plans to begin an incremental series of tests later this year.

“The concept design is done. I know what the approach is, I can put the numbers together,” Greason said of XCOR’s orbital vehicle plans.

“We’re not done yet,” said Jeff Greason, CEO of XCOR, said of Lynx in a presentation at the Space Access ’13 conference in Phoenix earlier this month. “It’s not because of any particular roadblock, but it’s just the usual 90-90 rule of project management: the first 90 percent takes the first 90 percent of the time, and the last 10 percent takes the other 90 percent of the time.”

While development of SpaceShipTwo’s hybrid rocket motor is widely believed to have been the major cause of that vehicle’s delays, Greason said propulsion is not an issue for Lynx. “Propulsion-wise, we’re in great shape,” he said, saying that the four engines, powered by liquid oxygen and kerosene, are now integrated into the fuselage of the Lynx Mark I prototype.

Instead, Greason said, XCOR has been working on a variety of other issues with the Lynx, including tweaks to the vehicle’s aerodynamics, avionics, and landing gear, as well as the production of the vehicle’s wings and a second fuselage. Flight tests are slated to begin in the second half of this year.

At Space Access, Greason also revealed new details about XCOR’s long-term plans to develop an orbital vehicle. “The concept design is done. I know what the approach is, I can put the numbers together,” he said. XCOR completed that concept in the last few months, he said, although hasn’t started a more detailed design of the system.

The concept, Greason explained, would use an existing aircraft, which Greason did not identify, and two reusable rocket-powered stages. The upper stage, he added, would likely use liquid hydrogen fuel, something XCOR had shied away from in the past, preferring to use kerosene or alcohol because it is easier to handle. The greater performance of hydrogen, plus the experience XCOR gained with it during a project with United Launch Alliance, eased those concerns. “For an orbital vehicle, if we have to add six to eight hours to the turnaround time to get half the mass, this is starting to look like a pretty good trade,” he said.

Greason didn’t go into greater detail about their orbital vehicle concept, but said he was targeting a price point of $1 million per person. “To me, that’s kind of the magic number,” he said, noting that space tourist Richard Garriott raised several million dollars to perform research on his flight to the International Space Station in 2008. “I’m pretty confident that, at a million dollars, going to orbit is like going to an offshore oil rig. People will pay you to do it because they need the labor on orbit to do things.”

Work on the Lynx suborbital vehicle and plans for a future orbital vehicle are keeping XCOR busy. The company now has nearly 50 employees, he said. “We’re up to so many people now it’s actually hard to get a group shot,” he quipped. The company’s Mojave facility is “packed to the gills” working on Lynx.

That space constraint was one of the motivations for the company’s announcement last year that it will move its headquarters and R&D facility to Midland, Texas (see “Texas warms to NewSpace”, The Space Review, July 16, 2012). “We couldn’t find any commercial real estate lender of any kind in the state of California” that would fund the development of a new facility there, despite a promise by the airport to pay the lease on the building if XCOR was no longer able to, he said.

The general business environment in California also drove XCOR to move to more business-friendly Texas, Greason added. The timing of the move, he said, is a function of both XCOR getting the Lynx flying and Midland International Airport, where XCOR will lease a large hangar, getting a spaceport license, and he offered no specific schedule of when the company would formally move to Midland.

“There are enough folks with experience and funding to back them up that I am absolutely convinced that, in just the next few years, we’re going to see multiple companies flying suborbital human spaceflight on a regular and frequent basis,” concluded the FAA’s Nield.

The third company developing suborbital crewed vehicles, Blue Origin, has maintained the low profile it has largely kept since its founding by CEO Jeff Bezos. Last October, the company announced the successful test of an escape system for the crew capsule that the company says could be used for both its orbital and suborbital vehicles. Earlier this year the company said it would extend its existing Space Act Agreement with NASA regarding commercial crew development of an orbital system, but has said little about its suborbital plans.

Two other companies that are not, for the time being, working on crewed suborbital vehicles are instead making progress on vehicles intended for uncrewed suborbital research and technology development missions. Masten Space Systems, also based on Mojave, flew a successful test of its XA-0.1B, or “Xombie,” reusable suborbital vehicle last month, flying to an altitude of 500 meters before returning to a powered landing. The flight tested a guidance system called GENIE, developed by Draper Labs, that NASA is interested in using for future planetary landers.

Masten is also completing development of its latest suborbital vehicle, Xaero B. It replaced the original Xaero, which was lost in a test flight in Mojave last September. Xaero B is initially designed to fly to an altitude of six kilometers; the company hints it will be capable of higher flights, “but we’ll talk more about that later in the flight test program,” they state in a note last month about its development.

Armadillo Aerospace, meanwhile, is regrouping after three test flights late last year and early this year of its STIG-B reusable suborbital rocket, all from Spaceport America in New Mexico. On the last flight, in January, the main parachute failed to deploy during descent, causing the rocket to crash 700 meters from the launch site.

Although STIG-B was lost, Armadillo took away some positive notes from the experience. “To the best of our knowledge this is the first time that a licensed, fully reusable, liquid bi-propellant rocket has been flown this many times,” noted Neil Milburn in a summary of the test. Armadillo now plans to build a “mini fleet” of at least three STIG rockets in order to support campaigns of launches for commercial customers as well as to provide redundancy in the event of a failure. Some changes in the design “will allow the next generation of STIG vehicles to readily reach space with substantially larger payloads,” Milburn said. His report didn’t discuss when those vehicles would be ready for flight.

In a presentation last week to the National Research Council’s Committee on Human Spaceflight in Washington, FAA associate administrator for commercial space transportation George Nield sounded a note of optimism about the state of commercial suborbital spaceflight, despite the delays companies have encountered. The committee was not initially interested in suborbital flight, focusing instead on human missions to low Earth orbit and beyond, but Nield argued that suborbital vehicles offer a number of benefits that make them relevant to the committee’s overall mandate, from gaining technical and operational experience that can be transferred to future orbital vehicles to keeping human spaceflight in the public spotlight while new orbital vehicles are being developed.

“We know that not all of these companies are going to be successful,” he said of suborbital ventures, acknowledging both technical and financial obstacles they face. “But there are enough folks with experience and funding to back them up that I am absolutely convinced that, in just the next few years, we’re going to see multiple companies flying suborbital human spaceflight on a regular and frequent basis.”

With an eye towards that long-term goal, today’s test flight could be an important milestone. Maybe.