Editing Sub-orbital spaceflight (section)

==Altitude requirement==
[[Image:Newton Cannon.svg|thumb|right|[[Newton's cannonball|Isaac Newton's Cannonball]]. Paths A and B depict a sub-orbital trajectory.]]
By definition, a sub-orbital spaceflight reaches an [[altitude]] higher than {{convert|100|km|abbr=on}} above [[sea level]]. This altitude, known as the Kármán line, was chosen by the [[Fédération Aéronautique Internationale]] because it is roughly the point where a vehicle flying fast enough to support itself with [[aerodynamic lift]] from the [[Earth's atmosphere]] would be flying faster than [[orbital speed]].<ref>{{cite web|url=http://www.fai.org/icare-records/100km-altitude-boundary-for-astronautics|title=100 km Altitude Boundary for Astronautics|publisher=[[Fédération Aéronautique Internationale]]|archive-url=https://web.archive.org/web/20110809093537/http://www.fai.org/astronautics/100km.asp|archive-date=2011-08-09|url-status=dead|access-date=2017-09-14}}</ref> The US military and [[NASA]] award [[Astronaut Badge|astronaut wings]] to those flying above {{convert|50|mi|abbr=on}},<ref>{{cite web|url=http://www.nasa.gov/centers/dryden/news/NewsReleases/2005/05-57.html|title=X-15 Space Pioneers Now Honored as Astronauts|first=Mary|last=Whelan|date=5 June 2013|website=nasa.gov|access-date=4 May 2018|url-status=live|archive-url=https://web.archive.org/web/20170611194526/https://www.nasa.gov/centers/dryden/news/NewsReleases/2005/05-57.html|archive-date=11 June 2017}}</ref> although the [[U.S. State Department]] does not show a distinct boundary between atmospheric flight and [[spaceflight]].<ref>{{cite web|url=https://2009-2017.state.gov/s/l/22718.htm|title=85. U.S. Statement, Definition and Delimitation of Outer Space And The Character And Utilization Of The Geostationary Orbit, Legal Subcommittee of the United Nations Committee on the Peaceful Uses of Outer Space at its 40th Session in Vienna from April|website=state.gov|access-date=4 May 2018}}</ref>