Lynx (spacecraft)

Lynx

Mockup of Lynx spaceplane
Function	Manned suborbital launch and reentry
Manufacturer	XCOR Aerospace
Size
Stages	(none, fully reusable spacecraft)
First flight	Upcoming
Boosters (Stage 0)
No. boosters	4
Engines
Thrust	2,900 pounds
Burn time
Fuel	LOX-Kerosene

The Lynx is a suborbital horizontal-takeoff, horizontal-landing (HTHL), rocket-powered spaceplane under development by the California-based company XCOR to compete in the emerging suborbital spaceflight market. The Lynx is projected to carry one pilot, a ticketed passenger, and/or a payload or small satellites above 100 km altitude. As of August 2012, the passenger ticket was projected to cost $95,000.^[1]

The concept has been under development since 2003, when a two-person suborbital spaceplane was announced under the name Xerus. Fabrication and assembly of the Lynx Mark I is currently underway, with the first flight of the spaceplane not expected before 2014.^[2]

History

Xerus

In 2003, XCOR proposed the Xerus (pronunciation: zEr'us) suborbital spaceplane concept. It was to be capable of transporting one pilot and one passenger as well as some science experiments and it would even be capable of carrying an upper stage which would launch near apogee and therefore would potentially be able to carry satellites into low-Earth orbit.^[3] As late as 2007, XCOR continued to refer to their future two-person spaceplane concept as Xerus,^[4]

Lynx

The Lynx was initially announced on March 26, 2008, with plans for an operational vehicle within two years.^[5] However, the build of the Lynx Mark I flight article did not commence until mid 2013 and, as of September 2013, the first flight is not projected until 2014, with commercial operations projected six months to a year afterwards.^[2]

Description

The Lynx will have four liquid rocket engines at the rear of the fuselage burning a mixture of LOX-Kerosene and each of them will produce 2,900 pounds-force (13,000 N) of thrust.^[6]

Mark I Prototype

• Maximum Altitude: 62 km (203,000 ft)^[1]
• Primary Internal Payload: 120 kg (260 lb)<^[7]
• Secondary payload spaces include a small area inside the cockpit behind the pilot or outside the vehicle in two areas in the aft fuselage fairing.^[7]
• Composite LOX tank^[8]
• Mach 2 (1,522 mph) speed of ascent^[9]
• 4G re-entry loading^[9]

Mark II Production Model

• Maximum Altitude: +107 km (351,000 ft)^[1]
• Primary Internal Payload: 120 kg (260 lb)^[10]
• Secondary payload spaces include the same as the Mark I.^[11]
• Non-toxic (non-hydrazine) reaction control system (RCS) thrusters,^[12] type 3N22^[13]
• Nonburnite LOX composite tank^[14]

Mark III

The Lynx Mark III is the same vehicle as the Mark II with External Dorsal Mounted Pod: 650 kg (1,430 lb) and is large enough to hold a two stage carrier to launch a microsatellite or multiple nanosatellites into low-Earth orbit.^[11]

Markets for microsat launch services are beginning to develop. As of December 2012, the U.S. government defense department is looking to have the capability to launch a "constellation of 24 micro-satellites (~20 kilograms (44 lb) range) each with 1-meter imaging resolution," through the DARPA SeeMe program.^[15]

Lynx XR-5K18 engine

The XR-5K18 is a piston pump fed LOX/RP-1 engine using an expander cycle.^[16] The engine chamber and regenerative nozzle are cooled by RP-1^[14][16]

The development program of the XCOR Lynx 5K18 LOX/kerosene engine reached a major milestone in March 2011. Integrated test firings of the engine/nozzle combination have demonstrated the ability of the "aluminum nozzle to withstand the high temperatures of rocket-engine exhaust over numerous tests, with no discernable degradation of the material properties of the alloys. The tests validated the design, materials and manufacturing processes used in the nozzle."^[17] Importantly, the 5K18 engine tests have "laid a foundation for scaling the design to EELV-sized engines"^[17]

In March 2011, United Launch Alliance (ULA) announced they had entered into a joint-development contract with XCOR for a flight-ready, 25,000 to 30,000 pounds-force (110,000–130,000 N) cryogenic LH2/LOX upper-stage rocket engine (see XCOR/ULA liquid-hydrogen, upper-stage engine development project). Partially as a result of positive results achieved from Lynx 5K18 effort to develop a new aluminum alloy engine nozzle using new manufacturing techniques, ULA believes the new engine technology will remove several hundred pounds of weight from the large engine and will lead to significantly lower-cost and more-capable commercial and US government space flights.^[18]

Airframe

It was reported in 2010 that the Mark I airframe could use a carbon/epoxy ester composite, and the Mark II a carbon/cyanate with a nickel alloy for the nose and leading-edge thermal protection.^[19]

Mark I build

The flight article Lynx Mark I is claimed as being fabricated and assembled in Mojave beginning in mid 2013. A blog on the company's website provides daily updates and background material.^[20] The cockpit of the Lynx (made of carbon fibre and designed by AdamWorks, Colorado) was reported as being one of the items that held up the assembly.^[7]

Test program

Tests of the XR-5K18 main engine began in 2008.^[21]

As of February 2011, engine tests were largely complete^[12] and the vehicle aerodynamic design had completed two rounds of wind tunnel testing. A third and final round of tests was completed in late 2011 using a "1/60-scale supersonic wind tunnel model of Lynx."^[12][9]

Flight tests of the Mark I prototype were expected to start in 2014.^[2][22]

Operations

Artists' depiction of Lynx on ground with people - XCOR Aerospace

The first engine hot fire tests were conducted on December 15, 2008.^[11] Wind tunnel tests were conducted in July 2009.^[23]

NASA sRLV program

As of March 2011, XCOR has submitted the Lynx as a reusable launch vehicle for carrying research payloads in response to NASA's suborbital reusable launch vehicle (sRLV) solicitation, which is a part of NASA's Flight Opportunities Program. XCOR projects 110 km (68 mi) altitude in flights of 30 to 45 minutes duration, while carrying up to 140 kg (310 lb) internal—or 650 kg (1,430 lb) external—of research payload. Flights will provide up to three minutes of microgravity below 0.01 g.^[24]

Commercial operations

According to XCOR, the Lynx will fly four or more times a day, and will also have the capacity to deliver payloads into space. A Lynx prototype called Mark I is expected to perform its first test flight in 2013,^[25] followed with a flight of the Mark II production model nine to eighteen months after. XCOR currently plans to have the Lynx's initial flights from the Mojave Air and Spaceport in Mojave, California^[26] or any licensed spaceport with a 2,400 meter (7900 ft) runway. Beginning in the first quarter of 2015 the Lynx is expected to be flying suborbital space tourism flights and scientific research missions from a new spaceport on the Caribbean island of Curaçao.^[27][28][29]

Because it lacks any propulsion system other than its rocket engines, the Lynx will have to be towed to the end of the runway. Once positioned on the runway, the pilot will ignite the four rocket engines and begin a steep climb. The engines will be shut off at approximately 138,000 feet (42 km) and Mach 2. The spaceplane will then continue to climb, unpowered until it reaches an apogee of approximately 200,000 feet (61 km). The spacecraft will experience a little over four minutes of weightlessness before re-entering the Earth's atmosphere. The occupants of the Lynx may experience up to four times normal gravity during re-entry. Once it has completed re-entry, the Lynx will then glide down and perform an unpowered landing. The total flight time is projected to last about 30 minutes.^[30] The Lynx is expected to be able to perform 40 flights before maintenance is required.

As of March 2011, Orbital Outfitters was designing pressure suits for XCOR use.^[31]

The successor to the Mark II is planned to be a two stage fully reusable orbital vehicle that takes off and lands horizontally.^[32]

Development costs

Mark 1 production is planned to cost $10 million,^[33][34] and mark 2 around $12 million.^[35]

See also

• EADS Astrium Space Tourism Project
• Private spaceflight
• Rocketplane XP
• SpaceShipTwo
• XCOR EZ-Rocket
• XCOR Mark-I X-Racer

References

External links

• Lynx Suborbital Spacecraft Page