A Member of Raffles Medical Group
“Ladies and Gentlemen, welcome into orbit. We will be completing one revolution around the Earth in the next 90 minutes, so do look out for your hometown below. Sunrise will be in 5 minutes if you’re looking for a photo-opportunity, but don’t worry if you miss it, because there will be 15 more chances today. On behalf of our captain and crew, I wish you an enjoyable spaceflight.”
If you have a gazillion dollars to spare, this could be the in-flight announcement you hear in the very near future. With the recent SpaceX Crew Dragon launch of NASA astronauts to the International Space Station (ISS), readily-available private space travel is on the cusp of reality for those who can afford its ‘astronomical’ price tag.
Obviously, humans are not built for space. We are adapted for a life on our sparkling blue haven, planet Earth. With its atmosphere, magnetic field, air and gravity, Earth is a stark contrast to the black vacuum of space. Spacecraft and spacesuits are designed to simulate an environment that can support human life, but our bodies still do experience some side effects from space travel.
Dr Morrison Loh, Head of Medical Directorate at Raffles Health Insurance, gives us an insight into some of the things early space tourists might experience during their short off-world excursions. Dr Loh also currently practices as a General Practitioner in Raffles Medical Group. Space Medicine is an area of interest to him, having completed the Space Medicine and Extreme Environment Physiology course at University College London.
During launch, the average g-force experienced by astronauts is around 3G, as powerful rockets propel the spacecraft skywards. That’s three times the usual gravitational force you experience on Earth, which is 1G, and roughly feels as though there are three clones of you sitting on your chest. A similar experience on Earth would be accelerating upwards on a rollercoaster ride, except that you’re only exposed to such high forces for a few seconds at a time. These sustained high g-forces can cause loss of consciousness in those untrained to withstand them.
Dr Loh: Our hearts are accustomed to pumping blood around our bodies in Earth’s gravity of 1G. When g-forces increase, it means that there is a much stronger downward force than usual. This causes blood to drain downwards away from your brain towards your feet, as the usual pumping force of your heart is no longer strong enough to push blood up towards your brain. This overall loss of blood supply to your head means that you might experience loss of vision or tunnel vision first as the blood supply to your eyes is reduced, followed by a loss of consciousness, as the blood supply to your brain is reduced. If the g-force is promptly reduced, you usually recover quickly with no harmful effects, although you might still feel disorientated for a short while. To reduce the effect of g-forces, the seats in current spacecraft are designed so that astronauts are essentially lying on their backs when the g-forces are highest at launch and re-entry. This allows the g-force to be distributed “horizontally” through their chest and back instead of “vertically” from their head to their feet, lowering their risk of losing consciousness.
Eight and a half minutes after launch, you will transition from being squashed by intense g-forces to immediately being weightless. An unearthly silence replaces the roaring from the engines as they cut off, telling you that you’ve entered the vacuum of space. With no gravity holding you to your seat anymore, you start to float, and rely on your seat’s harness to keep you in place.
If we were to compare this to a rollercoaster ride again, the feeling would be similar to the moment just before the rollercoaster plummets down a steep slope, where your stomach seems to hang uncomfortably in the air before gravity takes over again. In space, gravity never kicks in, and that uncomfortable feeling sticks around, sometimes progressing to vertigo, nausea and vomiting.
Dr Loh: Space sickness is a type of motion sickness experienced by more than 40-50% of astronauts when they first enter space, and can last for a few days. It is opposite to the type we have on Earth, like car sickness. Both types of motion sicknesses come a mismatch in information sent to our brains from our sensory systems. The two systems involved are the vestibular system, a delicate system in our inner ears that gives us balance and orientation, and our visual system, or what we see.
Our vestibular system relies on gravity as a reference point. Sitting inside a moving car on Earth, our vestibular system can sense that our body is moving and tells our brain that. However, to our eyes, our immediate surroundings, like the inside of the car or the seat in front of us, are not moving, which is why there is a mismatch in signals to the brain and we feel car sick.
In space, the lack of gravity completely throws our vestibular system off. We lose our reference point for what is up or down, and whether we are in motion or not. It is even possible to lose orientation of where our arms and legs are, because they are not being influenced by gravity. Our vestibular system, totally confused, tells our brain that we are not in motion. In contrast to this, our eyes are telling our brain as we look out the spacecraft windows that we are moving along really, really fast. This mismatch, coupled with the sudden change in g-forces, leads to the nausea and discomfort felt. Not everyone will experience space sickness, just as not everyone gets motion sickness on Earth.
After a few days in space, you notice that your face has started to swell. You might also be experiencing a stuffy or blocked nose. In contrast, your legs look much skinnier than usual. Some have coined the terms ‘moon-face’ and ‘chicken legs’ to describe this phenomenon.
Dr Loh: On Earth, gravity pulls the blood in your body towards the ground, which is why we can sometimes get swollen ankles if we stand upright or walk around for too long as blood pools in our legs. Being in the microgravity of space is similar to doing a constant headstand, as fluid in your body that is usually forced towards your feet freely moves up towards your head. This fluid shift can cause swelling of tissues such as those in your face and nose, giving you a puffy face and blocked nose. At the same time, your legs lose a lot of the fluid they usually have, which is why they appear skinner than usual.
Over the next few days, you’ll start to discover the little things that are different in space compared to on Earth. These might include eye-irritation, changes to taste, strange sweat and tears, and poor sleep.
Dr Loh: Microgravity is the cause of many of these changes. In space, dust and other small particles, including dead skin, do not settle to the floor as they do on Earth. These small particles remain floating around in the cabin, and can irritate the eyes of passengers. Without gravity, sweat and tears tend to clump together because of surface tension and remain attached to your skin instead of dripping off you in droplets. Your sleep would also be severely disrupted as you experience 16 sunrises and sunsets every 24 hours. 45-minute cycles of daylight and darkness mean that your body can no longer use the sun to gauge when to go to sleep. Disorientation can also lead to poor sleep quality, as well as the uncomfortable position of having to sleep strapped to a wall in a sleeping bag.
Apart from physical changes, venturing into space could also have a psychological impact on space tourists. One effect that is experienced even with short trips into space is known as the Overview Effect. It is described as a cognitive shift, or a profound moment of awareness, when you first lay eyes on Earth from afar. The realization that Earth is a tiny, fragile ball of life “hanging in the void”, protected by a paper-thin atmosphere, is what triggers the Overview Effect.
Dr Loh: The cognitive shift from the Overview Effect is thought to come from taking the whole world, with more than 7 billion people on it, in at a single glance. It appears to be similar to seeing ‘the big picture’, where there are no national boundaries, where differences between people fall away, and it’s just humanity and the Earth we are supposed to protect. Perhaps we could say that those who experience the Overview Effect grasp what it really means to be united as one species. The emotional response reported by astronauts who have experienced this effect is a strong sense of appreciation of the beauty of Earth, as well as need to connect to people and the Earth.
Even though space tourism to other planets like Mars will probably not be anytime soon, we still have our sights set on the Red Planet. With 3 missions to Mars this year, the latest being NASA’s Perseverance Rover (an apt name for 2020), it’s clear that human curiosity continues to push us to new horizons. Sending humans out beyond Earth’s protective magnetic field for long durations, however, is still unchartered territory.
Dr Loh: Long-haul space travellers will be exposed to a host of health risks, some of which include the effects of space radiation, cardiovascular problems, loss of muscle and bone mass due to their lack of use in microgravity and more. Social isolation could also greatly affect passengers, with a one-way trip to Mars alone lasting approximately 7 months. Picture being away from your loved ones, in close quarters with the same few people 24 hours a day for 7 months with minimal outside contact and probably no internet access. And that’s not counting the return leg of the trip, where you will have to do it all again. The mental and emotional strength needed for such a journey is immense. More in-depth studies are being carried out to determine how to tackle these issues so that future astronauts will be protected physically and psychologically when voyaging through the cosmos.
Space tourism is a stepping stone into our universe. The further we go, the more we learn about where we came from. Who knows how far humanity will venture from the shores of Earth, or if we will one day indeed be planting potatoes on Mars. Only time will tell.
Till then, live long and prosper.
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