Lynx spaceplane mockup.jpg
Mockup of Lynx spaceplane
FunctionCrewed suborbital launch and reentry
ManufacturerXCOR Aerospace
First stage
Thrust2,900 pounds

The XCOR Lynx was a proposed suborbital horizontal-takeoff, horizontal-landing (HTHL), rocket-powered spaceplane that was under development by the California-based company XCOR Aerospace to compete in the emerging suborbital spaceflight market. The Lynx was intended to carry one pilot, a ticketed passenger, and/or a payload above 100 km altitude. The concept was under development since 2003, when a two-person suborbital spaceplane was announced under the name Xerus.

In January 2016, XCOR changed plans for the first flight of the Lynx spaceplane. It was initially planned for the second quarter of 2016 from the Midland spaceport in Texas,[1] but in early 2016 it was pushed to an "undisclosed and tentative" date at the Mojave spaceport.[2]

In May 2016,[3] XCOR announced development of the Lynx had been halted with layoffs of approximately one-third of the staff; the company intended to concentrate on development of their liquid hydrogen rocket under contract with United Launch Alliance, instead.[4]

Following the bankruptcy of XCOR Aerospace in 2017, the assets of the company were sold to the nonprofit organization Build A Plane, which will focus on education rather than suborbital flight.[5]



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.[6] As late as 2007, XCOR continued to refer to their future two-person spaceplane concept as Xerus.[7]


The Lynx spaceplane was initially announced in March 2008, with plans for an operational vehicle within two years.[8] In December 2008 a ticket price of $95,000 per seat was announced, with flights intended to commence in 2010.[9] The build of the Lynx Mark I flight article did not commence until mid 2013 and, as of October 2014 XCOR claimed that the first flight would take place in 2015.[10][11] In July 2015 ticket prices increased by 50% to $150,000.[12] In November 2015, three co-founders left their existing positions with the company to start Agile Aero. Dan DeLong (Chief Engineer) and Aleta Jackson left the company entirely, while Jeff Greason, the former CEO, remained on the Board of Directors until he resigned in March 2016.[13] Greason cited problems with the Lynx vehicle body, although the engine had been a success. As of mid 2016, development was suspended in favor of a ULA contracted hydrolox engine, the 8H21.[4]

Passengers who had hoped to make flights in the Lynx included the winners from the Axe Apollo Space Academy contest, and Justin Dowd of Worcester, Massachusetts, the winner of another contest called the Race for Space.[14] Metro International's Race for Space newspaper contest.[15] As of July 2015, the passenger ticket was projected to cost $150,000.[16] As of December, 2015, was reportedly selling tickets for flights on the XCOR Lynx starting in 2016.[17]

In May 2016, the company halted development of the Lynx spaceplane and pivoted company focus toward development its LOX/LH2 engine technology, particularly on a funded project for United Launch Alliance. The company laid off more than 20 people of the 50–60 persons on board prior to May.[4]


The Lynx was intended to have four liquid rocket engines at the rear of the fuselage burning a mixture of LOX-Kerosene, each engine producing 2,900 pounds-force (13,000 N) of thrust.[18]

Mark I Prototype

Mark II Production Model

Mark III

The Lynx Mark III was intended to be the same vehicle as the Mark II with an External Dorsal Mounted Pod of 650 kg (1,430 lb) and was to be large enough to hold a two-stage carrier to launch a microsatellite or multiple nanosatellites into low Earth orbit.[26]

Lynx XR-5K18 engine

The XR-5K18 is a piston pump fed LOX/RP-1 engine using an expander cycle.[26] The engine chamber and regenerative nozzle are cooled by RP-1[25][26]

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 demonstrated the ability of the aluminum nozzle to withstand the high temperatures of rocket-engine exhaust.[27]

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). The Lynx 5K18 effort to develop a new aluminum alloy engine nozzle using new manufacturing techniques would remove several hundred pounds of weight from the large engine leading to significantly lower-cost and more-capable commercial and US government space flights.[28]


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.[29]

Mark I build

The flight article Lynx Mark I was claimed as being fabricated and assembled in Mojave beginning in mid 2013.[30] 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.[19]

At the start of October 2014, the cockpit was attached to the fuselage.[31] The rear carry-through spar was attached to the fuselage shortly after Thanksgiving 2014.[32] At the beginning of May 2015, the strakes were attached to the airframe.[33] The last major component, the wings, were expected to be delivered in late 2015.[34] In January 2016 XCOR's CEO Jay Gibson said "...we anticipate the wings to be there in the very near future..." and the CTO Michael Valant said they were finding that calibrating the flaps was a challenge.[35] In February 2016 the first prototype was described as a "wingless shell."[36]

In XCOR's November 2016 news report they stated that "Even though the program made great forward progress integrating the vehicle structural elements during 2015 and early 2016 the progress on the control surface elements lagged in design. In an effort to prevent potential rework resulting from implementing designs not yet mature the Lynx fabrication was paused, so our engineering team has gone back to the design board."[37]

Test program

Tests of the XR-5K18 main engine began in 2008.[38]

In February 2011, it was reported that engine tests were largely complete[23] 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."[20][23]

In October 2014, XCOR claimed that flight tests of the Mark I prototype would start in 2015.[10][11][39] However, by January 2016, technical hurdles led the company to state that they had not assigned a new projected date for test flights.[35]

Concept of operations

NASA sRLV program

In March 2011, XCOR 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.[40] No contract for providing this was ever announced.

Commercial operations

According to XCOR, the Lynx was intended to fly four or more times a day, and would have also had the capacity to deliver payloads into space. The Lynx Mark I prototype was expected to perform its first test flight in 2015,[11][41] followed by a flight of the Mark II production model twelve to eighteen months afterwards.[11]

XCOR had planned to have the Lynx's initial flights at the Mojave Air and Spaceport in Mojave, California[42] or any licensed spaceport with a 2,400 meter (7900 ft) runway. Media reports in 2014 anticipated that by the end of 2015[43] or in 2016 the Lynx was expected to begin flying suborbital space tourism flights and scientific research missions from a new spaceport on the Caribbean island of Curaçao.[44][45] However, the company stated in January 2016 that they had not assigned a new projected date for test flights and a date for the launch of commercial operations could not be anticipated.[35]

Because it lacked any propulsion system other than its rocket engines, the Lynx would have to be towed to the end of the runway. Once positioned on the runway, the pilot would have ignited the four rocket engines, take-off and begin a steep climb. The engines will be shut off at approximately 138,000 feet (42 km) and Mach 2. The spaceplane would then continue to climb, unpowered until it reached an apogee of approximately 200,000 feet (61 km). The spacecraft would have experienced a little over four minutes of weightlessness, before re-entering the Earth's atmosphere. The occupants of the Lynx were intended to have experienced up to four times normal gravity during re-entry. After re-entry, the Lynx would have glided down and performed an unpowered landing. The total flight time was projected to last about 30 minutes.[26] The Lynx was expected to be able to perform 40 flights before maintenance was required.

As of March 2011, Orbital Outfitters was reportedly designing pressure suits for XCOR use.[46][needs update]. In 2012, Orbital Outfitters reported that they had completed a technical mockup of the Lynx craft itself.[47]

Development cost projections

In 2008 Mark I production was projected to cost US$10 million,[48][49] and the Mark II around US$12 million.[50]

See also


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  4. ^ a b c Foust, Jeff (2016-05-31). "XCOR lays off employees to focus on engine development". SpaceNews. Retrieved 2016-07-13. has decided to focus the majority of its resources on the final development of the revolutionary liquid oxygen and liquid hydrogen (LH2) program. This innovative propulsion technology has applications to upper stage liquid hydrogen engines suitable for the Atlas V, Delta IV, and the planned NASA Space Launch System (SLS). ... XCOR’s problem is — and has always been — funding. There wasn’t enough of it to keep the Lynx staff.
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