No, this is not a rant about how (censored) I am the new Bond movie will not be available on free-to-air no matter how long I wait. Austrian goes up on a stratospheric balloon. Base camp radios up "Got vertigo?" "Nein, just 24 miles". I can't decide whether he truly broke the speed of sound (ie the sound barrier). Speed of sound at ground level is about 330 metres per second or 1200 km/h. However, the speed of sound goes up with decreasing pressure so I very much doubt he actually broke the sound barrier. If not the sound barrier, what's the point? At least Concorde broke the sound barrier (used to set my watch by it), even if when the in-cabin Mach-meter said "2.00" it wasn't actually going twice the speed of sound (at that altitude). As far as being the fastest "not in a vessel", the first spacewalk would have done that. Much faster.