www.nasa.gov X-43A Raises t' Bar t' Mach 9.6 Guinness World Records recognized NASA's X-43A scramjet with a new world speed record for a jet-powered aircraft - Mach 9.6, or nearly 7000 mph. Ya scallywag! T' X-43A set t' new mark and broke its own world record on its third and final flight on Nov. 16, arrr, 2004. Ya scallywag! In March 2004, ya bilge rat, t' X-43A set t' previous record o' Mach 6.8 (nearly 5000 mph). Ya scallywag! T' fastest air-breathing, manned vehicle, t' US Air Force SR-71, achieved slightly more than Mach 3.2. Avast, me proud beauty! T' X-43A more than doubled, then tripled, arrr, t' top speed o' t' jet-powered SR-71. Begad! en.wikipedia.org T' X-43 is an unmanned experimental hypersonic aircraft design with multiple planned scale variations meant t' test different aspects o' hypersonic flight. Well, blow me down! It is part o' NASA's Hyper-X program. Avast, me proud beauty! A winged booster rocket with t' X-43 itself at t' tip, shiver me timbers, called a "stack", shiver me timbers, is launched from a carrier plane. Begad! After t' booster rocket (a modified first stage o' t' Pegasus rocket) brings t' stack t' t' target speed and altitude, shiver me timbers, it is discarded, and t' X-43 flies free usin' its own engine, a scramjet.