Stunned by the failure of the first X-43 launch, NASA engineers work to discover the cause of the crash and prepare to launch the next hyper-X research vehicle. Follow engineers as they prepare the second X-43 in an attempt to reach a Mach-busting 7,000 miles an hour. Be at NASAâs mission control for the final countdown as the third X-43 fires its engine at a record-breaking Mach 10 speed.