What does it take for an astronaut to conduct a spacewalk?- Know-how Information, Novi Reporter
The DialogJul 22, 2021 15:17:55 IST
On June 25, astronauts Shane Kimbrough and Thomas Pesquet efficiently accomplished an virtually seven-hour EVA (extravehicular exercise, or spacewalk) to put in photo voltaic panels on the Worldwide Area Station. What does it take to don a spacesuit and enterprise out on such a technical and harmful mission? Surprisingly, one of many principal standards (in addition to the years of astronaut coaching) is physique dimension.
EVA capabilities blossomed in the course of the period of NASA’s area shuttle. Astronauts rode robotic arms, floated tetherless via the void utilizing jetpacks to steer, corralled satellites by hand, and constructed the Worldwide Area Station (ISS). They’ve carried out all of it whereas carrying spacesuits primarily based on the design first developed for the Apollo missions within the Nineteen Sixties.
Every swimsuit is a human-shaped spacecraft, that includes a backpack that homes a major life assist system; a layered, pressurised outer garment to guard astronauts from the area setting; and a “lengthy john” undergarment that circulates chilled water by way of tubes over the physique to cease the astronauts getting too sizzling inside their swimsuit.
When designing these “next-gen” spacesuits in 1974, NASA opted for a modular “tuxedo” strategy, during which the assorted parts (higher torso, decrease torso, helmet, arms and gloves) could possibly be blended and matched to suit particular person astronauts. The fits got here in 5 sizes, from further small to further giant, and had been primarily based totally on male physique shapes — females weren’t eligible for NASA’s astronaut program till 1978.
Quick-forward 47 years, and Kimbrough and Pesquet had been carrying these very same spacesuits whereas engaged on the ISS, regardless of the very fact the fits had been solely designed to final 15 years.
Today, NASA’s spacesuits are much less like bespoke tailoring and extra like the rest inventory at an outlet mall; of the 18 fits initially made by the next-gen program, solely 4 full fits stay. 4 had been misplaced within the Challenger and Columbia disasters, and others got here to the tip of their working lives and weren’t changed.
Which means to be chosen for an ISS spacewalk, an astronaut should match one of many two remaining obtainable sizes: males’s medium, or males’s giant. The primary all-female EVA, deliberate for March 2019, needed to be postponed as a result of just one medium-sized swimsuit was obtainable. One other medium swimsuit was ultimately cobbled collectively from spares, and astronauts Christina Koch and Jessica Meir efficiently carried out their groundbreaking spacewalk on October 18 2019.
Most EVAs are carried out in pairs, and flight controllers meticulously choreograph every astronaut’s actions effectively prematurely, to minimise “idle” time and full the duties as effectively as attainable.
Every EVA participant undergoes as much as ten hours of coaching per hour of EVA time, in a 12-metre-deep pool during which astronauts practise each side of their spacewalk, utilizing life-sized mock-ups of ISS parts.
Through the precise EVA, mission controllers on the bottom maintain a watchful eye on the astronauts’ progress, and the astronauts can talk with floor management, their EVA buddy and ISS crewmates as required.
Area is a harsh setting. The spacesuit supplies safety towards radiation, temperature extremes (starting from -270℃ to +120℃), and small particles of particles. To protect towards the danger of being hit by “area junk”, EVAs are scheduled for intervals of low danger, primarily based on the monitoring of identified objects.
Astronauts should additionally take steps to keep away from decompression illness, or “the bends”. Very like a scuba diver ascending too quick from a deep dive, an astronaut who strikes too quick from the pressurised area station to the decrease stress inside their spacesuit can undergo painful and probably lethal bubbles of nitrogen forming of their bloodstream. Earlier than an EVA, astronauts “camp out” in a single day within the ISS airlock at a diminished stress, to assist acclimatise earlier than donning their spacesuit.
Nobody has died throughout an EVA, however there have been some shut calls. The primary ever spacewalk, by Soviet cosmonaut Alexei Leonov in 1965, virtually resulted in catastrophe when the enlargement of his swimsuit within the vacuum of area virtually prevented him from re-entering the Voskhod capsule.
And on July 16 2013, Luca Parmitano entered the historical past books with two firsts: the primary Italian to carry out a spacewalk, and the primary near-drowning in area. Every week earlier than his EVA, one of many water pipes in his spacesuit had sprung a leak. However this info was not handed up the chain of command, and mission controllers authorised his EVA to start.
Inside an hour Luca had virtually two litres of water in his helmet, leaving him struggling to breathe. Unable to see out of his visor or talk with colleagues, Luca mentioned he used his tether to navigate his approach again to the security of the airlock.
Little question he and different astronauts shall be eager to don NASA’s new “exploration extravehicular mobility unit (xEMU)” spacesuits at the moment underneath growth for the Artemis program, NASA’s long-awaited return to the Moon.
Hopefully the Artemis moonwalkers can have extra choices when donning their swimsuit, which means astronauts could be chosen for missions as a result of they’ve received the proper stuff, with out additionally needing to be the proper dimension.
Steven Moore, Professor/Deputy Dean Analysis, College of Engineering and Know-how, CQUniversity Australia
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