XCOR Aerospace: Lynx Suborbital Vehicle

The Lynx is XCOR’s entry into the commercial reusable launch vehicle (RLV) market. This two-seat, piloted space transport vehicle will take humans and payloads on a half-hour suborbital flight to 100 km (330,000 feet) and then return safely to a landing at the takeoff runway.

Like an aircraft, Lynx is a horizontal takeoff and horizontal landing vehicle, but instead of a jet or piston engine, Lynx uses its own fully reusable rocket propulsion system to depart a runway and return safely. This approach is unique compared to most other RLVs in development, such as conventional vertical rocket launches and air-launched winged rocket vehicles “dropped” at altitude from a jet powered mothership.

The Lynx aircraft-like capabilities allow high tempo operations, up to four (4) flights per day, rapid call-up, fast turnaround between flights, low cost operations and maintenance (O&M), and a focus on safety and reliability.

Lynx has an all-composite airframe that makes it lightweight and strong. With an added thermal protection system (TPS) on the nose and leading edges it is able to handle the heat of re-entry from the edge of space. The wing area is sized for landing at moderate touchdown speeds near 90 knots. Lynx is about 9 meters (~30 feet) in length with a double-delta wing that spans about 7.5 meters (~24 feet).

Using the same concept of operations (CONOPS) as XCOR’s earlier rocket-powered vehicles, we have learned much about how to operate the Lynx, even though it has higher performance than our EZ-Rocket and X-Racer. From the EZ-Rocket we learned how to 1) develop a safe, reliable, and reusable propulsion system and integrate it into an airframe, 2) implement low cost, efficient, and safe operational procedures, and 3) work with the regulatory process. Building the X-Racer enabled us to 1) fly a previously designed and matured piston pump in a high performance rocket plane application, 2) improve low cost operations and safety regime processes, and 3) increase knowledge and skill sets for systems integration (airframe, avionics, and propulsion).

As with any production aircraft development program, XCOR has planned an initial test article, followed by several models of production vehicles that address different needs and markets.

The Lynx Mark I is the initial flight test vehicle now under development at XCOR’s Mojave, CA facilities. This prototype vehicle will be used to characterize and flight test the various sub-systems of the craft including life support, propulsion, tanks, structure, aeroshell, aerodynamics, re-entry heating and other design elements. It will undergo a flight test program beginning in late 2012 and continuing into 2013. The flight test program consists of a traditional envelope expansion regime in which the vehicle is gradually tested to its full flight profile . The Mark I will be placed into commercial service after being licensed as a launch vehicle under Federal Aviation Administration rules. The Lynx Mark I will also be used to train pilots and crew for the Lynx Mark II. The Lynx Mark I is designed to achieve an altitude of 200,000 feet (approximately 61 km).

The Lynx Mark II will begin construction and assembly during the Lynx Mark I development program . The Mark II is the production version of the Lynx, servicing both the suborbital tourism market and all markets that make use of the Lynx’s internal payload volumes, such as microgravity and biotechnology experiments. The Lynx Mark II uses the same propulsion and avionics systems as the Lynx Mark I, but has a lower dry weight and hence higher performance than the Mark I. The Mark II incorporates a lightweight composite LOX tank integral with the aeroshell and several other key innovations that are proprietary to XCOR. Designed to fly to 350,000 feet (approximately 106 km) , assuming certain payload weight conditions are met, the Mark II will take payloads and spaceflight participants to the edge of space and back. The Lynx Mark II is scheduled to enter flight service beginning in 2014.

The Lynx Mark III is a highly modified derivative of the Lynx Mark II that features the ability to carry an external dorsal pod with either a payload experiment or upper stage capable of launching a small satellite into low earth orbit. Total payload capacity for the external dorsal pod is 650kg. The Lynx Mark III is a different vehicle from the Mark II, featuring upgraded landing gear, aerodynamics, core structural enhancements , and features a more powerful propulsion package and other modifications needed to carry the extra weight aloft. A production time line for the Lynx Mark III is not set in stone, but we expect to roll this version of the craft out in 2015 or 2016.

Lynx propulsion is four XR-5K18 rocket engines, each producing 12.9 kN (2900 lbf) vacuum thrust with kerosene and liquid oxygen propellants. Engine detail design began in autumn of 2008. The first hot fire test was conducted on 15 December 2008 and continues today.

Lynx will operate as an FAA AST-licensed suborbital reusable launch vehicle. XCOR already has successfully passed the AST licensing process with an earlier vehicle concept, and we have been actively involved in the development of the statutory and regulatory framework within which Lynx will operate. Lynx will have aircraft-like operations up to four times per day from any licensed spaceport with a 2,400 meter (7,900 ft) runway, suitable abort options, fast turnaround (two hours), low maintenance intervals (designed for 40 flights before preventive maintenance action), and low cost operations. Lynx operates under visual flight rules (VFR), and initially it will only fly during days of good visibility. Mojave Air and Space Port, the planned first operating location for Lynx, has good visibility 360 days per year and acceptable winds 345 days per year.

The Lynx will offer several multi-mission primary and secondary payload capabilities including: in-cockpit experiments, externally mounted experiments, test pilot/astronaut training, upper atmospheric sampling, microsatellite launch / ballistic trajectory research (Mk. III / US capability only), and personal spaceflight (space tourism). “Primary” payloads pay for the flight, while “secondary” payloads are on a ride-share basis with a primary payload, typically for a nominal ride-share fee.

Lynx vehicles will carry primary payloads located in the area to the right of the pilot or in the case of the Mk. III (US only) on the top of the vehicle in an experiment pod. Secondary payloads will be carried in a variety of locations. For the "Mk II" version of the Lynx, the primary internal payload will accommodate a maximum mass of 120 kg (265 lbs) to 100 km (330,000 ft). This “right seat” can be a human in a pressure suit, two stacked Space Shuttle middeck lockers (MDLs), or a standard 19 inch electronic equipment rack. For the US based Mk. III vehicle only, the primary payload location is an external dorsal mounted pod, which holds up to 650 kg (1433 lbs)and is large enough to hold a space telescope or a two stage carrier to launch multiple nanosatellites into low Earth orbit. This pod can also carry experiments that return with the vehicle. Secondary payload spaces in all versions include a small area inside the cockpit behind the pilot or outside the vehicle in two areas in the aft fuselage fairing (see image below). Detailed specifications of the payload spaces can be found in the Lynx Payload Users Guide.


	Lynx External Payload Locations - Click to Enlarge		Lynx Cabin Payload Locations - Click to Enlarge

The Lynx Experience for a Participant

The View at Apogee from Lynx participant seat

A spaceflight participant will sit to the right and just aft of the pilot. Lynx will have a pressurized cabin, and pilot and participant will wear full pressure suits during flight for safety in case of an emergency. The pressure suit is custom designed for XCOR by Orbital Outfitters, who have built in some of the most highly advanced features ever found in an emergency pressure suit.

Prior to a Lynx flight, potential spaceflight participants will go through a screening process, which will take place over five days and four nights and includes familiarizing the participant with all aspects of the suborbital flight experience. To make their flight safer and more enjoyable, spaceflight participants will engage in medical screenings, seminars, altitude chamber training, and a g-force experience.

Watch the Lynx Experience Video:

Watch the Lynx Animation: