Perlan Project Inc. is a 501(c)(3) not-for-profit aeronautical exploration and atmospheric science research organization that utilizes sailplanes (gliders) designed to fly at extremely high altitudes. On 29 August 2006 Steve Fossett and Einar Enevoldson, the pilots of Perlan Mission I, broke the existing altitude record for gliders by soaring up to 50,671 feet (15,460m) in a standard glider using stratospheric waves of air. The Fédération Aéronautique Internationale has ratified the altitude record of achieved on 2 September 2018, a substantial improvement over the previous year's best altitude of , which was set on 3 September 2017. These flights used the custom designed and built pressurized high-altitude Windward Performance Perlan II glider, sponsored by Airbus. They also collected data about earth’s atmosphere and its ozone layer. Meteorological basis of the missions Standing mountain waves are a source of rising air used in the sport of soaring. Riding these waves, similar in some ways to surfing on an ocean wave, has been widely used to reach great altitudes in sailplanes since they were discovered by German glider pilots, including Wolf Hirth, in 1933 in the Riesengebirge. This method uses the powerfully rising and sinking air in mountain waves. Gliders regularly climb in these waves to high altitudes. Prior to the 4 September 2017 flight, the glider absolute world altitude record stood at 15,460 meters (50,727 feet), which is the altitude reached by Steve Fossett and Einar Enevoldson during Perlan Mission I. The previous record was 14,938 meters (49,009 feet). It was set in 1986 by Robert R. Harris, flying from California City and reaching his record height over Mount Whitney, California. This may be near the limit for standing mountain waves in temperate latitudes, although in unusual meteorological conditions much higher altitudes may be achievable. Standing waves normally do not extend above the tropopause at temperate latitudes. A strong west wind usually decreases above the tropopause, which has been shown to cap or prevent the upward propagation of standing mountain waves. However, at the outer boundary of the polar vortex, in winter, the stratospheric polar night jet exists. Its wind field can join with the wind field of the polar jet stream. The result is a wind which increases with altitude through the tropopause and upward to 100,000 feet or above. When this conjunction of winds occurs over a barrier mountain, standing mountain waves will propagate through that entire altitude range. Einar