How many orbiters did NASA originally plan to build for the Space Shuttle program? Didn't 20+ launches per year seem like too much for a fleet of four orbiters? - Quora
Space Shuttle - Wikiwand
Space Shuttle | Space Agency Wiki | Fandom
Space Shuttle - Wikipedia
File:Space Shuttle USA.png - Wikimedia Commons
Space Shuttle - FlightGear wiki
Space Shuttle - FlightGear wiki
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