![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2021\/07\/X-15-scaled.jpg\")
<\/p>\nAfter years of development, suborbital space tourism looks ready to lift off after Virgin Galactic successfully launched its first fully-crewed suborbital mission to space on July 11 following several prior crewed suborbital tests. The Unity 22 mission came just days before Blue Origin is scheduled to make its first passenger suborbital mission no earlier than Tuesday, July 20 using its New Shepard system. <\/p>\n
Both companies have been developing suborbital spacecraft for over a decade, with the ultimate goal of carrying paying customers to the edge of space and back along with an added commitment to take science experiments along on some but not all of those flights as well.<\/p>\n<\/p>\n
History of human suborbital spaceflight<\/b><\/p>\n
On May 5, 1961, Alan Shepard became the first person to fly a suborbital mission to space. And became the first American to travel to space in the process. Shepard\u2019s mission launched from Cape Canaveral and took his Freedom 7 Mercury capsule to an altitude of 187.5 km, before making a safe splashdown in the Atlantic ocean.<\/p>\n
After Shepard\u2019s flight, the Air Force\u2019s X-15 hypersonic rocket-powered aircraft also began making suborbital flights. On July 17, 1962, during X-15 Flight 62, pilot Robert M. White flew the rocket-powered spaceplane up to an altitude of 95.9 km, crossing the boundary to space at 80 km as used by the United States.<\/p>\n
The X-15 conducted a total of 13 suborbital spaceflights between 1962 and 1968, including two that crossed the K\u00e1rm\u00e1n line (the 100 km boundary to space used officially by most of the world \u2014 read Jonathan McDowell\u2019s paper examining where the aerodynamic-to-gravity-dominate boundary to space likely resides). Those two flights were piloted by Air Force pilot Joseph A. Walker and remain the highest flights achieved by the X-15.<\/p>\n
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An X-15 in flight. (Credit: US Air Force)<\/p>\n
Although the X-15 was operated by the U.S. Air Force and NASA, and was never intended for tourism, the program helped pave the way for the development of commercial suborbital rocket powered spaceplanes such as Virgin Galactic\u2019s SpaceShipOne and SpaceShipTwo.<\/p>\n
Space tourism guides (adsbygoogle = window.adsbygoogle || []).push({});<\/p>\n In May 1996, the Xprize, later renamed the Ansari X Prize, promised to award $10 million to the first non-government organization to launch a crewed spacecraft to space and back twice within two weeks.<\/p>\n The goal of the prize was to help spur the development of low-cost spaceflight, a must if a commercial market was ever to develop. The competition comprised 26 teams from around the world who raced to develop a spacecraft that would meet the requirements.<\/p>\n The prize was won on October 4, 2004, when Scaled Composites completed its second piloted suborbital flight within two weeks using their SpaceShipOne spaceplane. The first flight for the prize occurred five days earlier on September 29.<\/p>\n This was the third time SpaceShipOne was launched, with the first flight occurring on June 24, 2004. The flights, respectively, reached 100.1 km, 102.9 km and 112 km.<\/p>\n Virgin Galactic<\/b><\/p>\n Founded in 2004 by billionaire entrepreneur Sir Richard Branson, Virgin Galactic\u2019s goal was to develop and operate commercial spacecraft in order to launch paying customers on suborbital spaceflights past the U.S.-defined 80 km mark.<\/p>\n VSS Unity is the second SpaceShipTwo vehicle developed by Virgin Galactic. The first, VSS Enterprise was lost in a deadly accident over the Mojave Desert in California on October 31, 2014. <\/p>\n After a successful climb to altitude and release from its carrier aircraft, VSS Enterprise ignited its engine at 15 km altitude to begin climbing. Just 11 seconds into the burn, the co-pilot prematurely unlocked the feathering mechanism, resulting in the violent aerodynamic breakup of the Enterprise.<\/p>\n The breakup ejected pilot Peter Siebold, still strapped to his seat, who managed to unbuckle himself \u2014 despite severe injuries \u2014 and safely parachute to the ground. Co-pilot Michael Alsbury died in the crash.<\/p>\n The National Transportation Safety Board (NTSB) ultimately determined the cause of the accident to be a combination of pilot error, inadequate pilot training, spacecraft design flaws that provided no safeguards against accidental pilot command of critical systems at the wrong time in flight, and the FAA for approving the experimental test flight without paying adequate attention to human safety factors or providing guidance.<\/p>\n VSS Unity, named by physicist Stephen Hawking, was about 65% complete at the time of Enterprise\u2019s loss and incorporates lessons learned and post-accident redesigns.<\/p>\n VSS Unity can carry up to four passengers and two pilots. After taking off from Spaceport America in New Mexico, Unity is carried up to just under 15 km by its carrier aircraft VMS Eve. Once at the drop altitude, Unity is released from its mothership and enters a short free fall before igniting its single hybrid rocket motor.<\/p>\n![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2021\/07\/Enterprise.jpg\")
The company currently operates the SpaceShipTwo, named VSS Unity, and the WhiteKnightTwo, VMS Eve, carrier aircraft. The first SpaceShipThree craft, the VSS Imagine, was recently unveiled and is awaiting ground and flight tests scheduled to begin this summer (northern hemisphere).<\/p>\nSee Also<\/h4>\n
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