Author Topic: Space Ship Two - General Thread  (Read 708691 times)

Offline Borklund

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Re: Space Ship Two - General Thread
« Reply #1500 on: 07/04/2014 11:39 pm »
Re: space suits, or lack thereof (pages 99 and 100)

My argument is this: Flying into space without a space suit is reckless behaviour. It puts the lives of crew and passengers at significant risk for no reason. The human body cannot sustain itself at altitudes above ca 10-15 km/33-50k feet. Crew and passengers are at risk of severe hypoxia for pretty much all of the flight, from WK2 release through to gliding down below the aforementioned 10-15 km "limit". At altitudes above 20 km, you will die in a matter of seconds, with little to no time to react.

There could be any number of scenarios where the spacecraft remains fully or largely intact and is able to return safely to Earth, but the pressurised cabin fails; a broken valve, a tiny crack in the hull, a catastrophic engine malfunction - the list could go on and on. When the SS2 engine fires the craft is on a suborbital trajectory and it will eventually come down to Earth again. Why not bring along a very lightweight and unintrusive backup in the form of a space suit to maximise the chances of crew and passenger survival? Without space suits, it's not a question of could they survive. They will die.

This is what happened to the crew of Soyuz 11. The craft made it back safely to Earth, entirely intact and working perfectly, save for a malfunctioning breathing ventilation valve that the crew had neither the time or ability to react to and fix. Georgy Dobrovolsky, Vladislav Volkov, Viktor Patsayev would have survived had they been wearing space suits. This is an indisputable fact.

Ever since Soyuz 11 every single manned spaceflight has seen astronauts and cosmonauts wear space suits to orbit and back down. ISS is a shirtsleeve environment because the pressurised volume is so great that crew would have adequate time to react to a breached hull, ISS modules have better shielding and any breached segment(s) can be evacuated and separated from the remaining intact modules where the crew can seek shelter. Small spacecraft afford no such luxury. Even a system as reliable as Soyuz is not impervious to failures. SpaceShipTwo is guaranteed to be less reliable, so why take a greater risk? Even commercial aircraft - who fly at altitudes of around 9-12 km - carry backup oxygen supply and oxygen masks in case the pressurised cabin fails. While you wouldn't die immediately at those altitudes, you would if the aircraft maintained that altitude for more than a few minutes at best.

We're talking about clothes that you wear on your body with a very low added mass - a few kilograms at the most - and a cost of a few tens/hundreds of thousands of dollars per unit. Compare the cost of potentially losing the entire business vs that of purchasing a few space suits. Compare the cost (in dollars and mass) of designing, building, testing and implementing double-redundant ECLSS vs that of having crew and passengers wear space suits.
« Last Edit: 07/05/2014 12:01 am by Borklund »

Online Chris Bergin

Re: Space Ship Two - General Thread
« Reply #1501 on: 07/05/2014 12:57 am »
« Last Edit: 07/05/2014 12:59 am by Chris Bergin »
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