A great deal of design work has been done by Greg Cole of Windward Performance to show that a sailplane for 90,000 feet is relatively straightforward, while 100,000 feet is possible, although more difficult and expensive. Windward Performance will build the sailplane of high performance pre-preg in production-quality tooling. The sailplane requires relatively high-end design, analysis, and construction, to be flutter-safe at very high true air speeds, and strong enough for the potentially heavy turbulence that could be encountered at 90,000 feet. It must also have well-proven, fail-safe pressurization and cabin air re-cycling systems.