XCOR Lynx

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. 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 US$95,000 (equivalent to US$129,124 in 2022) 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 XCOR claimed that the first flight would take place in 2015.[10][11] In July 2015, ticket prices increased by 50% to US$150,000 (equivalent to US$185,189 in 2022).[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] By July 2015, the passenger ticket was projected to cost US$150,000.[16] As of December 2015, Kayak.com 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]

• Maximum Altitude: 62 km (203,000 ft)[16]
• Primary Internal Payload: 120 kg (260 lb)[19]
• 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.[19]
• Aluminum LOX tank
• Mach 2 (1,500 mph) speed of ascent[20]
• 4G re-entry loading[20]

• Maximum Altitude: 107 km (351,000 ft)[16]
• Primary Internal Payload: 120 kg (260 lb)[21]
• Secondary payload spaces include the same as the Mark I.[22]
• Non-toxic (non-hydrazine) reaction control system (RCS) thrusters,[23] type 3N22[24]
• Nonburnite LOX composite tank[25]

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]

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]

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.[39] No contract for providing this was ever announced.

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][40] 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[41] or any licensed spaceport with a 2,400-metre (7,900 ft) runway. Media reports in 2014 anticipated that, by the end of 2015 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.[42][43] 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.[2]

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.

Orbital Outfitters was reportedly designing pressure suits for XCOR use.[44] In 2012, Orbital Outfitters reported that they had completed a technical mockup of the Lynx craft itself.[45]

In 2008, Mark I production was projected to cost US$10 million (equivalent to US$14 million in 2022),[46][47] and the Mark II around US$12 million (equivalent to US$16 million in 2022).[48]