Posted on February 18, 2012 by Tim Peake
Learning to ‘spacewalk’
One of the most captivating images of spaceflight, at least to my mind, does not portray the staggering power released by a 3000 tonne rocket departing the Earth, nor the grace of a space station the size of a football pitch gliding over an ocean. For me, it is the image of an astronaut floating freely in space, surveying the Universe at will, unencumbered by Earth’s annoying (yet rather essential) gravity that epitomises human achievement. When I’m asked which astronaut has inspired me the most, the temptation is to recite the more obvious ‘first’ achievements of Yuri Gagarin, Neil Armstrong or Alexey Leonov.
The truth is the picture of Bruce McCandless conducting the first untethered Extra-Vehicular Activity (EVA – more commonly known as ‘spacewalk’), is not only supremely inspirational but it leaves me wondering what must that feel like…really feel like. The elation of absorbing a view that is simply unsurpassed, the exposure and isolation of floating 200m from the Shuttle’s sanctuary and the apprehension of knowing that only a few layers of material separate you from the perils of deep vacuum, crippling temperatures, radiation and micrometeorites. Thankfully those few layers of material have triumphed over the harsh environment of space and to date hundreds of EVA’s have been conducted by astronauts from many different countries.
And that is what brings me to the Gagarin Cosmonaut Training Centre (Star City) in January 2012, with my good friend Thomas Pesquet - to learn about the “Orlan MK”, Russia’s latest spacesuit designed to protect astronauts whilst conducting EVA. On completion of our training we will be qualified to conduct an EVA using this system, having learnt how to maintain and operate the suit, conduct airlock depressurisation and repressurisation drills and to deal with emergency situations should they arise.
Our 5 week course begins – as always – in the classroom. Like a small child in the days before Christmas we have to endure hours of waiting (in our case…theory) before we can play with our toys. However, this is my kind of theory. A spacesuit is like a mini space station with its own life support, electrical power, thermal control, voice and data communications and computer control systems – all designed to keep an astronaut alive for up to 10 hours in space. Having spent the best part of my career studying similar systems on numerous types of aircraft I have developed a rather ‘nerdy’ passion for understanding how things work and so it is with some gusto that I begin to pore over the engineering diagrams in our training manuals.
I’ll try not to bore you with the ‘techie stuff’ but if you’ll permit me a couple of paragraphs…the suit’s most vital component is oxygen, not only to breathe but also for pressure…and this spacesuit has oxygen in abundance. There are 2 tanks each capable of supplying over 800 litres of oxygen. In the spacesuit we breathe pure oxygen and consume about 50 litres per hour, so under normal conditions each tank will last over 16 hours. Exhaled carbon dioxide is removed by a lithium ion filter and fresh oxygen is released into the suit to compensate for the resulting pressure drop. Electric fans circulate the oxygen around the suit – it’s a beautifully simple design built to typically robust Russian standards.
The suit has to be internally pressurised to protect against the vacuum of space – without external pressure all the gases are released from our bloodstream, including oxygen of course, and an astronaut would lose consciousness after about 15 seconds. No need to dwell on the more gruesome discussions about whether or not our blood would ‘boil’ or body expand – we’d be blissfully unconscious! However, if the suit were pressurised to a ‘normal’ earth atmosphere at sea level (760mmHg) it would be so rigid when operating in a vacuum that an astronaut would be virtually unable to move. So the “Orlan” operates at a safe compromise of 300mmHg, which means our body experiences the same pressure as if you were standing on top of a mountain at 23000 feet (breathing pure oxygen). Even at this pressure the suit feels extremely rigid and the simplest tasks such as operating switches, levers, turning valves – anything that requires the bending of elbows or fingers – is extremely difficult, as Thomas and I were soon to discover.
So with our week of theory complete, at last it was time to wear the spacesuits, suspended from the ceiling in the ‘dry’ simulator. The process begins with a short medical evaluation prior to donning medical monitoring equipment, cotton undergarments, socks, headset and a liquid cooling suit. The cooling suit will pump water around the body and expel excess heat into space – it’s an extremely efficient system and each suit has a temperature control lever for comfort. Sliding carefully, feet first into the suit I am reminded of my recent caving experience with ESA, squeezing into tight spaces that you’re not sure how to get out of. As the backpack is locked and sealed I am thankful that I have never had problems being in restricted spaces – I actually feel quite comforted by the confines of the spacesuit but I can imagine that for anyone who suffers even the slightest feelings of claustrophobia this would be akin to medieval torture.
A correctly fitted suit is essential - and because the suit will expand once pressurised it has to be slightly too small when you first enter, but despite being a bit cramped it’s not uncomfortable and soon I am learning how to move my arms. “Think like a robot” Oleg, our Russian instructor tells us, “and move slowly – conserve energy.” This works well and soon Thomas and I are familiarising ourselves with the spacesuit’s mechanical and computerised controls. After 3 hours of working under pressure (literally!), we emerge from our spacesuits with a newfound respect for just how hard it must be to conduct a real 6 hour EVA. Muscles that I never knew existed are sore, I’ve had something scratching my eye for the past hour which I’ve been unable to do anything about, I’m dehydrated and have cramp in my wrists, arms and fingers. But we are smiling – possibly the biggest smiles since experiencing zero ‘g’ during parabolic flight. This is what being an astronaut is about!
As we begin to find working in the spacesuit easier with each dry simulation, the tasks become more complex and it is not long before we are ready to progress to the final stage of our training - the ‘Hydrolab’. The Hydrolab at Star City is a circular pool 10m deep and 24m diameter. Mock-ups of the Russian segments of the International Space Station are lowered on a platform into the water and astronauts can practise EVA skills using the neutral buoyancy of water to simulate weightlessness. Sealed in my spacesuit once again, I am being lowered into the pool by a small crane – and for a fleeting moment I wonder what would happen if there were a catastrophic suit failure underwater – like a glove popping off…sometimes ignorance is bliss, I guess. As we submerge I begin to survey my new surroundings. The curvature of the visor gives a slight ‘fish bowl’ effect and I soon learn it is better not to move my head back and forth too much as it is slightly disorientating.
Thomas and I are placed into the airlock and the clock is running. There is barely room to move. Tasks which were relatively easy in scuba gear the day before require ridiculous amounts of concentration, effort and time and after 20 minutes all we have achieved is to open the hatch, install a hatch seal protector and egress the airlock with all our kit. We move along our planned route attaching our safety tethers ‘via ferrata’ style to the handrails, with always two points of contact. Every move is being watched by several cameras and we know that any mistake will be pounced upon, for good reason - the odds of successful rescue for an astronaut ‘lost in space’ are not good. As each task is accomplished I can feel the strength being sapped from my arms and fingers. The suit has expanded and doesn’t fit too well anymore but I’m happy I’ll complete the EVA with some energy to spare. That is, until I realise that Thomas has been instructed to ‘play’ unconscious – an emergency situation that requires one astronaut to recover the other to the airlock, doing all the drills alone. It’s going to be a long morning! After about 3 and half hours underwater we are finally back on dry land, delighted to have successfully completed our first ‘suited’ dive. After such a strange and unique experience it seems perfectly normal that the first thing that happens as we step out of our suits is to be handed a cup of hot tea by a kind Russian doctor – how civilised is that!
An EVA is probably the most physically demanding task an astronaut can undertake. In hindsight, Bruce McCandless may not have been “surveying the Universe at will” - he was probably trying desperately to bend his fingers to reach the thruster control and return to the Shuttle, with sweat stinging his eyes and a microphone sticking up his nose - nursing sore elbows and fingers and suffering complete and utter muscle fatigue. Does that in any way spoil the image for me? Not one bit – if anything I look at that picture today with greater wonder, admiration and inspiration than I did 5 weeks ago.