SHUTTLE STUDIES PRINCIPAL ISSUES HYPERGOLIC REACTION CONTROL SYSTEM OR LIQUID OXYGEN/HYDROGEN FLY-BY-WIRE FLIGHT CONTROL SYSTEM WIND TUNNEL TESTS TO DETERMINE WING SIZE AND CONFIGURATION AIR BREATHING ENGINES WERE CONSIDERED FOR FLY BACK, LATER WERE DETERMINED TO BE TOO HEAVYSHUTTLE STUDIES • PRINCIPAL ISSUES: – HYPERGOLIC REACTION CONTROL SYSTEM OR LIQUID OXYGEN/HYDROGEN – FLY￾BY-WIRE FLIGHT CONTROL SYSTEM – WIND TUNNEL TESTS TO DETERMINE WING SIZE AND CONFIGURATION – AIR BREATHING ENGINES WERE CONSIDERED FOR FLY BACK; LATER WERE DETERMINED TO BE TOO HEAVY 4