Wednesday, March 18, 2015

50th Anniversary of the first Space Extravehicular Activity

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.