NASHVILLE, Tenn. — A multibillion-dollar annual market for space tourism and science flights could emerge within the next five years, projects suborbital spaceflight hopeful XCOR Aerospace, which aims to begin flight tests of its first Lynx reusable launch vehicle by the end of this year.

Mojave, Calif.-based XCOR plans to begin final assembly of the Lynx Mark I this month, setting it on course for rocket-powered flights up to altitudes of 200,000 ft. beginning in 2013. The initial vehicle is the development pathfinder for a Mark II production version designed to carry a passenger and experiments to 350,000 ft. from 2014 onward. A Lynx Mark III, aimed at service entry in 2015-16 and configured with an external dorsal payload pod, is also in final design.

The two-seat Lynx is a single-stage, reusable, liquid-rocket-powered vehicle that will take off and land horizontally. Designed to fly to altitudes of 106 km (66 mi.) up to four times per day, the 27.9-ft.-long, 24-ft.-span vehicle is being developed to tap into an “addressable” market for space tourism and launch services worth $6 billion a year by 2016, according to Andrew Nelson, business development vice president.

Although XCOR is realistic enough to know it will capture only part of this potential business, Nelson says signs of burgeoning demand are increasingly evident. “After 2017 a sizable part of the global space market will be addressed by new players. Our current estimate is that a $5-6 billion annual market will be enabled by suborbital reusable launch vehicles. It will be the starting point for a future trillion-dollar market,” he asserts.

Of the overall $6 billion, XCOR estimates the launch services market for people as well as Earth observation, materials science, upper-atmosphere research and microgravity experiments could be worth $3.3 billion. Passenger traffic alone is estimated at $800 million, with the bulk of this — $700 million — coming from space tourism and the balance from government-funded research flights. Payloads are expected to generate $1.1 billion, while the small-satellite launch business is estimated at $1.4 billion — with U.S.-based customers buying up to $500 million of capacity per year.

The first composite fuselage for the Lynx is set to arrive at Mojave from a South Carolina supplier by the end of January. “This will be put on a mobile test trailer and integrated with the four-engine propulsion system,” says Lynx Program Manager Khaki Rodway McKee. Bids for final assembly of the cockpit pressure vessel and other structures are due to “go out next week,” with deliveries due in April or May, she says.

Updating progress at the American Institute of Aeronautics and Astronautics’ Aerospace Sciences meeting here, McKee and Nelson gave first details of design changes made to improve the stability and control of the final configuration. Modifications to the original sharp-nosed shape were made after subsonic wind-tunnel trials in 2009 at the U.S. Air Force Research Laboratory (AFRL) in Dayton, Ohio, revealed a stubborn post-stall pitch-up condition. Follow-on tests at Marshall Space Flight Center in Huntsville, Ala., conducted jointly with AFRL, prompted further design refinements to improve stability.

As a result of the changes, which delayed the first flight by two years from a planned 2010 debut, the nose section is now broader and the chine extended farther outboard. The wingtip-mounted vertical tails have also been redesigned with a longer chord and extended ventral fins for added stability. The aft-body housing beneath the engine cluster has also been extended with a deeper, squared-off tail replacing the original faired design.

Design of the liquid-oxygen tank is complete, components ordered and the first part — a slosh baffle — has been delivered. “We also selected a commercial-off-the-shelf [COTS] landing gear. It is all in hand, and is being tested with a drop test,” McKee says .

Avionics are “mostly COTS” and will be integrated into the airframe around May-June. “We plan to complete full integration of the Lynx by the end of the summer and taxi tests will begin in October-November,” she says.

Flight-ready XR-5K18 engines have been built, and test firings of a prototype engine are under way to characterize propellant efficiency. Fuel pumps have been tested to “full Lynx power” and are ready to be integrated, while flight-weight versions of the liquid-oxygen pumps are undergoing bench testing. To date, the pumps have accumulated around 60 min. of test time and are “working up to full-power tests,” McKee says.