Four years after the rocket-powered Lynx project was unveiled at the Los Angeles Convention Center, the presence here of a full-scale vehicle mockup at the Spacecraft Technology Expo reveals two fundamental truths about the “new space” market.

Firstly, propelling a privately developed spacecraft to suborbit is extremely difficult. When it first announced the project in March 2008, XCOR Aerospace hoped to be flying within two years, yet is only now assembling the first Mark I vehicle at its Mojave, Calif., facility. The company's long journey to suborbit is partly reflected in the many detailed design differences between the mockup and the artist's concept of 2008.

Secondly, the project shows staying power while underscoring XCOR's determination and the resilience of the market. Despite the challenges and the sluggish economy, the company continues to find support and raise funds. XCOR holds more than $60 million in backlog orders and recently closed a $5 million round of equity funding from new and previous investors, including Silicon Valley entrepreneurs and well-known technology “angel” investors such as Esther Dyson.

XCOR CEO Jeff Greason also continues to exude confidence in the project and the market as a whole. “It took a while, but we think we're there,” he says, describing the path to Lynx. “We've been through two generations of rocket-powered vehicles so far. Firstly, there was the EZ-Rocket between 2001 and 2005, which was aimed at pushing down the cost of rocket-powered operations. Then there was the X-Racer, between 2006 and 2008, which was all about operational tempo. We got it down to around nine minutes between flights and up to seven flights per day.”

Now, with the prospect of long-awaited suborbital flights looming in 2013, Greason says the influence of pioneering operations such as the Lynx will be greater than the sum of its parts. “People talk about the tradeoff between robotic operations and humans—but I don't think a robot has been invented that can enjoy the spaceflight for me, or can do experiments and say, 'Mmmm . . . that looks funny to me.' So it's a game-changer in a way that will impact other uses of human spaceflight.”

Assembly of the initial vehicle is underway, with the truss structure that will support the propulsion system currently being attached to the fuselage. The structure will provide a housing for the vehicle's four XR-5K18 liquid oxygen/kerosene (LOX/RP) rocket engines. Initial tests of the LOX piston pump are about to start, paving the way for closed-loop testing of the engine using its own pump-fed fuel, rather than pressure-fed from offboard sources. XCOR has also received the LOX tank and is issuing requests for bids for the aerodynamic strakes, or fairings, which will enclose the fuel tanks between the fuselage and the wing.

The mockup at the show indicated the changes made to improve the stability and control of the final configuration, including the broader nose section and extended chine. Other changes—which were made after subsonic wind-tunnel trials in 2009 at the U.S. Air Force Research Laboratory in Dayton, Ohio, and follow-on tests at NASA Marshall Space Flight Center—included larger-chord wingtip-mounted vertical fins with extended ventral sections. A final set of wind-tunnel campaigns in both facilities is scheduled shortly to confirm minor aerodynamic changes.

A mockup of the two-person cockpit was also displayed alongside the vehicle. The layout is dominated by two multi-function displays, numerous standby instruments and a camera view of the rocket plume. XCOR says visual checks of the plume from a tail-mounted camera will provide the pilot with instant verification of the stability of the rockets, and will warn of issues before anything is picked up on instruments. The company says avionics provided by L-3 Communications, CMC/Esterline, Aspen, MGL, Avidyne and Garmin “are all being considered,” and a final decision on the suite of avionics suppliers will be made over the summer.

XCOR aims to start powered taxi tests later this year with high-speed runs by December, and first flight in 2013.

Lynx Suborbital Spacecraft Specifications
Lynx Mark I Lynx Mark II Lynx Mark III
Primary payload mass Internal: 120 kg (265 lb.)External: 280 kg (620 lb.) Internal: 120 kg (265 lb.) Internal: 120 kg (265 lb.)External: 650 kg (1,430 lb.)
Minimum turnaround time 4 hr. 2 hr. 2 hr.
Microgravity time 56 sec. 3 min. 3 min.
Nominal apogee 61 km (200,000 ft.) 100 km (328,000 ft.) 100 km (328,000 ft.)
Source: XCOR Aerospace