Even though Soviet era Lt. Col. Alexey Leonov did his first 10-minute
extravehicular activity – or EVA – back in March 18, 1965, why is it that
Hollywood still haven’t managed to portray a scientifically-accurate one in
movies?
By: Ringo Bones
Ever wondered why Hollywood movies still haven’t managed to
portray a scientifically-accurate portrayal of an extravehicular activity or spacewalk – i.e.
movies like Clint Eastwood’s Space Cowboys and the recent one that stars Sandra
Bullock titled Gravity – even when it is already 50 years after Soviet era
cosmonaut Lt. Col. Alexey Leonov did a 10-minute long EVA back in March 18,
1965 and Major Edward White did a 20-minutte long EVA back in July 3, 1965? Is
it all due to a lack of scientifically-accurate information of the subject?
All extravehicular activity in space using current
spacesuits available to us today requires a lengthy pre-breathing of pure
oxygen at reduced pressures, tragically, due to the Apollo I fire that happened
back in April 24, 1967 that killed Major Ed White, Gus Grissom and Roger
Chaffee. Prior to the Apollo I fire, NASA astronauts breathe – i.e. use –
oxygen in their cabin that is at the same atmospheric pressure as their
spacesuits – i.e. 29-percent of the atmospheric pressure at sea level or 4.3
pounds per square inch. This is the reason why Ed White more or less donned his
spacesuit within 3 minutes or so before stepping out of his capsule – instead of
a 40 minute to 4-hour pre-breathing pure oxygen at 4.3 pounds per square inch
before stepping out in a spacesuit into the vacuum of space – like astronauts
had done when they change spacecraft “atmospheres” to an oxygen-nitrogen mix at
11.3 pounds per square inch – equivalent to about the prevailing atmospheric
pressure 7,000 feet above sea level or about 75-percent less than the 14.7 psi
sea level atmospheric pressure - and the same system used in commercial
passenger jets.
Blame it on the quirk of human physiology that NASA
astronauts have to pre-breathe pure oxygen at 4.3 psi for 40 minutes to 4 hours
depending on the duration of the EVA. If not, they would suffer the bends – i.e.
formation of painful nitrogen bubbles in their blood vessels and joints. A
lengthy pre-breathing scene is something not even portrayed in Space Cowboys
and the movie Gravity – even just a truncated 30 to 90 second scene for semblance
of “scientific authenticity”. It would have been a great opportunity to insert
a Hamlet-like soliloquy in these scenes before they don their Hamilton Standard
life support backpacks to their 15-million US dollar spacesuits as they ready
to step out into the great void. Lt. Col. Alexey Leonov’s and Major Ed White’s
trailblazing EVA’s are still a stuff of legend indeed 50 years on.
