"Together, we proved that a human in freefall can break the speed of sound returning from near space, going through a transonic phase and landing safely on the ground, " said Dr Jonathan Clark, a former space shuttle flight surgeon and the Red Bull Stratos medical director.

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Before joining the astronaut corps in 2004, Marshburn worked as a flight surgeon for NASA. He flew to the space station once before, in 2009, on the STS-127 space shuttle mission.

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Boarding the jet in her now-famous body suit (inspired by the compression suits used by human athletes such as Aussie hurdler Sally Pearson), Black Caviar -- who is affectionately known as "Nelly" -- was accompanied on the flight by her personal track rider and veterinary surgeon to make sure she remained relaxed during transit.

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According to NASA flight surgeon Smith Johnston, studies in Anchorage, Alaska showed that hospital staff made more medical errors during the darkest times of the year.

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