The standing position is a first for a manned space vehicle. To date, only NASA astronaut Storey Musgrave had attempted this during an atmosphere re-entry in the space shuttle, during which he would have been subject to accelerations less than 2g. The mission profile for the Tycho Brahe capsule should only comprise a minute of thrust with an acceleration not exceeding 3g. Furthermore, the passenger will be equipped with a pressure suit to prevent the famous “blackout” that fighter pilots sometimes experience when they are subject to intense acceleration during cornering or sharp “pull out” manoeuvres.
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| View of the Tycho Brahe capsule. In dark grey the “seat” and to the left the telescopic mast for aerodynamics like for ballistic missiles fired from submarines. Credit: Copenhagen Suborbitals. |
“For a healthy individual, blackout occurs at around 4.7 g of longitudinal acceleration, that is, in a standing position," explains Dr Bernard Comet, a specialist in aerospace medicine at Medes in Toulouse. “The use of a pressure suit can mean 1.2g more.” These figures are taken from exhaustive studies conducted by the US Air Force in the 1960s and which are still used for reference today.
“No loss of consciousness is harmless” Dr Comet insists. Blackout is caused by a failure in the blood flow to the brain. If this is sustained, it may result in necrosis. Eventually, depending on how long the blood flow is interrupted, the consequences range from brain injury to death.
