In 1972, the Space Race officially ended as NASA sent one last crew of astronauts to the surface of the Moon (Apollo 17). This was the brass ring that both the US and the Soviets were reaching for, the “Moonshot” that would determine who had supremacy in space. In the current age of renewed space exploration, the next great leap will clearly involve sending astronauts to Mars.
It’s not easy living and working in space for extended periods of time. As NASA’s Twins Study illustrated, microgravity takes a toll on human physiology, which is followed by a painful transition back to normal gravity (just ask Scott Kelly!) Aside from muscle and bone degeneration, there’s diminished organ function, effects on cardiovascular health, the central nervous system, and “subtle changes” on the genetic level.
Until now, the biggest unanswered question was what the underlying cause of these physical impacts was. But after reviewing all of the data accumulated from decades of research aboard the International Space Station (ISS) – which included the Twins Study and DNA samples taken from dozens of astronauts – an international team of researchers came to the conclusion that mitochondria might be the driving force for these changes.
The ESA has a science lab on the International Space Station called Columbus. Inside that lab is the Fluid Science Laboratory, dedicated to studying the behaviour of fluids in microgravity. Currently, that lab is being used to study a substance most of us probably don’t spend much time thinking about: foam.
Ever since astronauts began going to space for extended periods of time, it has been known that long-term exposure to zero-gravity or microgravity comes with its share of health effects. These include muscle atrophy and loss of bone density, but also extend to other areas of the body leading to diminished organ function, circulation, and even genetic changes.
For this reason, numerous studies have been conducted aboard the International Space Station (ISS) to determine the extent of these effects, and what strategies can be used to mitigate them. According to a new study which recently appeared in the International Journal of Molecular Sciences, a team of NASA and JAXA-funded researchers showed how artificial gravity should be a key component of any future long-term plans in space.
On March 1st, 2016, American astronaut Scott Kelly returned to Earth after spending a total of 340 days aboard the International Space Station (ISS). As part of NASA’s goal to send astronauts on long-duration space flights to Mars and beyond, this record-setting stay in space was designed to test the limit of human endurance in a microgravity environment.
Also known as the Twin Study, this experiment consisted of Kelly spending nearly a year in space while his identical twin (Mark Kelly) remained on Earth. Since Kelly’s return, the two have been subjected to medical tests to see what long-term effects microgravity has had of Scott’s Kelly’s physique. The final results of this test, which were just released, reveal that Scott has experienced changes at the genetic level.
The study was conducted by NASA’s Human Research Program, and the preliminary findings were released at their Investigator’s Workshop on the week of January 23rd, 2017. According to these findings, Scott Kelly showed indications of inflammation, changes in his telomeres and telomerase (parts of the chromosonal system related to aging), a decrease in bone density and gastrointestinal changes – all of which were expected.
As NASA reported in their preliminary findings:
“By measuring large numbers of metabolites, cytokines, and proteins, researchers learned that spaceflight is associated with oxygen deprivation stress, increased inflammation, and dramatic nutrient shifts that affect gene expression… After returning to Earth, Scott started the process of readapting to Earth’s gravity. Most of the biological changes he experienced in space quickly returned to nearly his preflight status. Some changes returned to baseline within hours or days of landing, while a few persisted after six months.”
At the same time, the study took into account possible genomic and cognitive changes between the two brothers. These findings were recently clarified by NASA, which indicated that 93% of Scott Kelly’s genes returned to normal after he returned to Earth while the remaining 7% points were missing. These were attributed to “longer-term changes in genes related to his immune system, DNA repair, bone formation networks, hypoxia, and hypercapnia.”
In other words, in addition to the well-documented effects of microgravity – such as muscle atrophy, bone density loss and loss of eyesight – Scott Kelly also experienced health effect caused by a deficiency in the amount of oxygen that was able to make it to his tissues, an excess of CO2 in his tissues, and long-term effects in how his body is able to maintain and repair itself.
At the same time, the report indicated that Scott Kelly experienced no significant changes when it came to cognitive performance. The preliminary findings touched on this, indicating that Scott showed a slight decrease in speed and accuracy when undergoing cognitive performance testing compared to his brother. This decrease was more pronounced when he first landed, but was attributed to readjustment to Earth’s gravity.
Mathias Basner – a professor at the University of Pennsylvania, Philadelphia, who was in charge of conducting the tests – also found no real difference in cognition between 6 month and 12 month missions. This is especially important since typical stays aboard the ISS last six months, whereas long term missions to Mars would take 150-300 days – depending on the alignment of the planets and the speed of the spacecraft.
A two way trip to Mars, as well as the time spent in Mars lower-gravity environment (37.6 % that of Earth’s), could take multiple years. As such, the Twin Study was intrinsic to NASA’s efforts to prepare for its proposed “Journey to Mars“, which is expected to take place sometime in the 2030s. These and other studies being conducted aboard the ISS seek to determine what the long-term effects on astronaut health will be, and how they can be mitigated.
The NASA Twin Study was the result of a partnership between 10 individual investigations, 12 colleges and universities, NASA’s biomedical labs and the National Space Biomedical Research Institute Consortium.
Scott Kelly’s stay in space and the Twin Study will also be the subject of a PBS documentary titled “Beyond a Year in Space“. Be sure to check out the teaser trailer here:
The microgravity in space causes a number of problems for astronauts, including bone density loss and muscle atrophy. But there’s another problem: weightlessness allows astronauts’ spines to expand, making them taller. The height gain is permanent while they’re in space, and causes back pain.
A new SkinSuit being tested in a study at King’s College in London may bring some relief. The study has not been published yet.
The constant 24 hour microgravity that astronauts live with in space is different from the natural 24 hour cycle that humans go through on Earth. Down here, the spine goes through a natural cycle associated with sleep.
Sleeping in a supine position allows the discs in the spine to expand with fluid. When we wake up in the morning, we’re at our tallest. As we go about our day, gravity compresses the spinal discs and we lose about 1.5 cm (0.6 inches) in height. Then we sleep again, and the spine expands again. But in space, astronauts spines have been known to grow up to 7 cm. (2.75 in.)
Study leader David A. Green explains it: “On Earth your spine is compressed by gravity as you’re on your feet, then you go to bed at night and your spine unloads – it’s a normal cyclic process.”
In microgravity, the spine of an astronaut is never compressed by gravity, and stays unloaded. The resulting expansion causes pain. As Green says, “In space there’s no gravitational loading. Thus the discs in your spine may continue to swell, the natural curves of the spine may be reduced and the supporting ligaments and muscles — no longer required to resist gravity – may become loose and weak.”
The SkinSuit being developed by the Space Medicine Office of ESA’s European Astronaut Centre and the King’s College in London is based on work done by the Massachusetts Institute of Technology (MIT). It’s a spandex-based garment that simulates gravity by squeezing the body from the shoulders to the feet.
The Skinsuits were tested on-board the International Space Station by ESA astronauts Andreas Mogensen and Thomas Pesquet. But they could only be worn for a short period of time. “The first concepts were really uncomfortable, providing some 80% equivalent gravity loading, and so could only be worn for a couple of hours,” said researcher Philip Carvil.
Back on Earth, the researchers worked on the suit to improve it. They used a waterbed half-filled with water rich in magnesium salts. This re-created the microgravity that astronauts face in space. The researchers were inspired by the Dead Sea, where the high salt content allows swimmers to float on the surface.
“During our longer trials we’ve seen similar increases in stature to those experienced in orbit, which suggests it is a valid representation of microgravity in terms of the effects on the spine,” explains researcher Philip Carvil.
Studies using students as test subjects have helped with the development of the SkinSuit. After lying on the microgravity-simulating waterbed both with and without the SkinSuit, subjects were scanned with MRI’s to test the SkinSuit’s effectiveness. The suit has gone through several design revisions to make it more comfortable, wearable, and effective. It’s now up to the Mark VI design.
“The Mark VI Skinsuit is extremely comfortable, to the point where it can be worn unobtrusively for long periods of normal activity or while sleeping,” say Carvil. “The Mk VI provides around 20% loading – slightly more than lunar gravity, which is enough to bring back forces similar to those that the spine is used to having.”
“The results have yet to be published, but it does look like the Mk VI Skinsuit is effective in mitigating spine lengthening,” says Philip. “In addition we’re learning more about the fundamental physiological processes involved, and the importance of reloading the spine for everyone.”
After the historic Apollo Missions, which saw humans set foot on another celestial body for the first time in history, NASA and the Russian Space Agency (Roscosmos) began to shift their priorities away from pioneering space exploration and began to focus on developing long-term capabilities in space. In the ensuing decades (from the 1970s to 1990s), both agencies began to build and deploy space stations, each one bigger and more complex than the last.
The latest and greatest of these is the International Space Station (ISS), a scientific facility that resides in Low-Earth Orbit around our planet. This space station is the largest and most sophisticated orbiting research facility ever built and is so large that it can actually be seen with the naked eye. Central to its mission is the idea of fostering international cooperation for the sake of advancing science and space exploration.
Planning for the ISS began in the 1980s and was based in part on the successes of Russia’s Mir space station, NASA’s Skylab, and the Space Shuttle Program. This station, it was hoped, would allow for the future utilization of low-Earth Orbit and its resources, and serve as an intermediate base for renewed exploration efforts to the Moon, mission to Mars, and beyond.
In May of 1982, NASA established the Space Station task force, which was charged with creating a conceptual framework for such a space station. In the end, the ISS plan that emerged was a culmination of several different plans for a space station – which included NASA’s Freedom and the Soviet’s Mir-2 concepts, as well as Japan’s Kibo laboratory, and the European Space Agency’s Columbus laboratory.
The Freedom concept called for a modular space station to be deployed to orbit, where it would serve as the counterpart to the Soviet Salyut and Mir space stations. That same year, NASA approached the Japanese Aerospace and Exploration Agency (JAXA) to participate in the program with the creation of the Kibo, also known as the Japanese Experiment Module.
The Canadian Space Agency was similarly approached in 1982 and was asked to provide robotic support for the station. Thanks to the success of the Canadarm, which was an integral part of the Space Shuttle Program, the CSA agreed to develop robotic components that would assist with docking, perform maintenance, and assist astronauts with spacewalks.
In 1984, the ESA was invited to participate in the construction of the station with the creation of the Columbus laboratory – a research and experimental lab specializing in materials science. The construction of both the Kibo and Columbus modules was approved in 1985. As the most ambitious space program in either agency’s history, the development of these laboratories was seen as central to Europe and Japan’s emerging space capability.
In 1993, American Vice-President Al Gore and Russian Prime Minister Viktor Chernomyrdin announced that they would be pooling the resources intended to create Freedom and Mir-2. Instead of two separate space stations, the programs would be working collaboratively to create a single space station – which was later named the International Space Station.
Construction of the ISS was made possible with the support of multiple federal space agencies, which included NASA, Roscosmos, JAXA, the CSA, and members of the ESA – specifically Belgium, Denmark, France, Spain, Italy, Germany, the Netherlands, Norway, Switzerland, and Sweden. The Brazilian Space Agency (AEB) also contributed to the construction effort.
The orbital construction of the space station began in 1998 after the participating nations signed the Space Station Intergovernmental Agreement (IGA), which established a legal framework that stressed cooperation based on international law. The participating space agencies also signed the Four Memoranda of Understandings (MoUs), which laid out their responsibilities in the design, development, and use of the station.
The assembly process began in 1998 with the deployment of the ‘Zarya’ (“Sunrise” in Russian) Control Module, or Functional Cargo Block. Built by the Russians with funding from the US, this module was designed to provide the station’s initial propulsion and power. The pressurized module – which weighed over 19,300 kg (42,600 pounds) – was launched aboard a Russian Proton rocket in November 1998.
On Dec. 4th, the second component – the ‘Unity’ Node – was placed into orbit by the Space Shuttle Endeavour (STS-88), along with two pressurized mating adapters. This node was one of three – Harmony and Tranquility being the other two – that would form the ISS’ main hull. On Sunday, Dec. 6th, it was mated to Zarya by the STS-88 crew inside the shuttle’s payload bay.
The next installments came in the year 2000, with the deployment of the Zvezda Service Module (the first habitation module) and multiple supply missions conducted by the Space Shuttle Atlantis. The Space Shuttle Discovery (STS-92) also delivered the station’s third pressurized mating adapted and a Ku-band antenna in October. By the end of the month, the first Expedition crew was launched aboard a Soyuz rocket, which arrived on Nov. 2nd.
No additional modules or components were added until 2016 when Bigelow Aerospace installed their experimental Bigelow Expandable Activity Module (BEAM). All told, it took 13 years to construct the space station, an estimated $100 billion and required more than 100 rocket and Space Shuttle launches, and 160 spacewalks.
As of the penning of this article, the station has been continuously occupied for a period of 16 years and 74 days since the arrival of Expedition 1 on November 2nd, 2000. This is the longest continuous human presence in low Earth orbit, having surpassed Mir’s record of 9 years and 357 days.
Purpose and Aims:
The main purpose of the ISS is fourfold: conducting scientific research, furthering space exploration, facilitating education and outreach, and fostering international cooperation. These goals are backed by NASA, the Russian Federal Space Agency (Roscomos), the Japanese Aerospace Exploration Agency (JAXA), the Canadian Space Agency (CSA), and the European Space Agency (ESA), with additional support from other nations and institutions.
As far as scientific research goes, the ISS provides a unique environment to conduct experiments under microgravity conditions. Whereas crewed spacecraft provide a limited platform that is only deployed to space for a limited amount of time, the ISS allows for long-term studies that can last for years (or even decades).
Many different and continuous projects are being conducted aboard the ISS, which are made possible with the support of a full-time crew of six astronauts, and a continuity of visiting vehicles (which also allows for resupply and crew rotations). Scientists on Earth have access to their data and are able to communicate with the science teams through a number of channels.
The many fields of research conducted aboard the ISS include astrobiology, astronomy, human research, life sciences, physical sciences, space weather, and meteorology. In the case of space weather and meteorology, the ISS is in a unique position to study these phenomena because of its position in LEO. Here, it has a short orbital period, allowing it to witness weather across the entire globe many times in a single day.
It is also exposed to things like cosmic rays, solar wind, charged subatomic particles, and other phenomena that characterize a space environment. Medical research aboard the ISS is largely focused on the long-term effects of microgravity on living organisms – particularly its effects on bone density, muscle degeneration, and organ function – which is intrinsic to long-range space exploration missions.
The ISS also conducts research that is beneficial to space exploration systems. Its location in LEO also allows for the testing of spacecraft systems that are required for long-range missions. It also provides an environment where astronauts can gain vital experience in terms of operations, maintenance, and repair services – which are similarly crucial for long-term missions (such as missions to the Moon and Mars).
The ISS also provides opportunities for education thanks to participation in experiments, where students are able to design experiments and watch as ISS crews carry them out. ISS astronauts are also able to engage classrooms through video links, radio communications, email, and educational videos/web episodes. Various space agencies also maintain educational materials for download based on ISS experiments and operations.
Educational and cultural outreach also fall within the ISS’ mandate. These activities are conducted with the help and support of the participating federal space agencies and are designed to encourage education and career training in the STEM (Science, Technical, Engineering, Math) fields.
One of the best-known examples of this is the educational videos created by Chris Hadfield – the Canadian astronaut who served as the commander of Expedition 35 aboard the ISS – which chronicled the everyday activities of ISS astronauts. He also directed a great deal of attention to ISS activities thanks to his musical collaboration with the Barenaked Ladies and Wexford Gleeks – titled “I.S.S. (Is Somebody Singing)” (shown above).
His video, a cover of David Bowie’s “Space Oddity”, also earned him widespread acclaim. Along with drawing additional attention to the ISS and its crew operations, it was also a major feat since it was the only music video ever to be filmed in space!
Operations Aboard the ISS:
As noted, the ISS is facilitated by rotating crews and regular launches that transport supplies, experiments, and equipment to the station. These take the form of both crewed and uncrewed vehicles, depending on the nature of the mission. Crews are generally transported aboard Russian Progress spacecraft, which are launched via Soyuz rockets from the Baikonur Cosmodrome in Kazakhstan.
Roscosmos has conducted a total of 60 trips to the ISS using Progress spacecraft, while 40 separate launches were conducted using Soyuz rockets. Some 35 flights were also made to the station using the now-retired NASA Space Shuttles, which transported crew, experiments, and supplies. The ESA and JAXA have both conducted 5 cargo transfer missions, using the Automated Transfer Vehicle (ATV) and the H-II Transfer Vehicle (HTV), respectively.
In more recent years, private aerospace companies like SpaceX and Orbital ATK have been contracted to provide resupply missions to the ISS, which they have done using their Dragon and Cygnus spacecraft. Additional spacecraft, such as SpaceX’s Crew Dragon spacecraft, are expected to provide crew transportation in the future.
Alongside the development of reusable first-stage rockets, these efforts are being carried out in part to restore domestic launch capability to the US. Since 2014, tensions between the Russian Federation and the US have led to growing concerns over the future of Russian-American cooperation with programs like the ISS.
Crew activities consist of conducting experiments and research considered vital to space exploration. These activities are scheduled from 06:00 to 21:30 hours UTC (Universal Coordinated Time), with breaks being taken for breakfast, lunch, dinner, and regular crew conferences. Every crew member has their own quarters (which includes a tethered sleeping bag), two of which are located in the Zvezda Module and four more installed in Harmony.
During “night hours”, the windows are covered to give the impression of darkness. This is essential since the station experiences 16 sunrises and sunsets a day. Two exercise periods of 1 hour each are scheduled every day to ensure that the risks of muscle atrophy and bone loss are minimized. The exercise equipment includes two treadmills, the Advanced Resistive Exercise Device (ARED) for simulated weight training, and a stationary bicycle.
Hygiene is maintained thanks to water jets and soap dispensed from tubes, as well as wet wipes, rinseless shampoo, and edible toothpaste. Sanitation is provided by two space toilets – both of Russian design – aboard the Zvezda and Tranquility Modules. Similar to what was available aboard the Space Shuttle, astronauts fasten themselves to the toilet seat and the removal of waste is accomplished with a vacuum suction hole.
Liquid waste is transferred to the Water Recovery System, where it is converted back into drinking water (yes, astronauts drink their own urine, after a fashion!). Solid waste is collected in individual bags that are stored in an aluminum container, which are then transferred to the docked spacecraft for disposal.
Food aboard the station consists mainly of freeze-dried meals in vacuum-sealed plastic bags. Canned goods are available, but are limited due to their weight (which makes them more expensive to transport). Fresh fruit and vegetables are brought during resupply missions, and a large array of spices and condiments are used to ensure that food is flavorful – which is important since one of the effects of microgravity is a diminished sense of taste.
To prevent spillage, drinks and soups are contained in packets and consumed with a straw. Solid food is eaten with a knife and fork, which are attached to a tray with magnets to prevent them from floating away, while drinks are provided in dehydrated powder form and then mixed with water. Any food or crumbs that floats away must be collected to prevent them from clogging the air filters and other equipment.
Life aboard the station also carries with it a high degree of risk. These come in the form of radiation, the long-term effects of microgravity on the human physique, the psychological effects of being in space (i.e. stress and sleep disturbances), and the danger of collision with space debris.
In terms of radiation, objects within the Low-Earth Orbit environment are partially protected from solar radiation and cosmic rays by the Earth’s magnetosphere. However, without the protection of the Earth’s atmosphere, astronauts are still exposed to about 1 millisievert a day, which is the equivalent of what a person on Earth is exposed to during the course of a year.
As a result, astronauts are at higher risk for developing cancer, suffering DNA and chromosomal damage, and diminished immune system function. Hence why protective shielding and drugs are a must aboard the station, as well as protocols for limiting exposure. For instance, during solar flare activity, crews are able to seek shelter in the more heavily shielded Russian Orbital Segment of the station.
As already noted, the effects of microgravity also take a toll on muscle tissues and bone density. According to a 2001 study conducted by NASA’s Human Research Program (HRP) – which researched the effects on an astronaut Scott Kelly’s body after he spent a year aboard the ISS – bone density loss occurs at a rate of over 1% per month.
Similarly, a report by the Johnson Space Center – titled “Muscle Atrophy” – stated that astronauts experience up to a 20% loss of muscle mass on spaceflights lasting just five to 11 days. In addition, more recent studies have indicated that the long-term effects of being in space also include diminished organ function, decreased metabolism, and reduced eyesight.
Because of this, astronauts exercise regularly in order to minimize muscle and bone loss, and their nutritional regimen is designed to make sure they the appropriate nutrients to maintain proper organ function. Beyond that, the long-term health effects, and additional strategies to combat them, are still being investigated.
But perhaps the greatest hazard comes in the form of orbiting junk – aka. space debris. At present, there are over 500,000 pieces of debris that are being tracked by NASA and other agencies as they orbit the Earth. An estimated 20,000 of these are larger than a softball, while the remainder are about the size of a pebble. All told, there are likely to be many millions of pieces of debris in orbit, but most are so small they can’t be tracked.
These objects can travel at speeds of up to 28,163 km/h (17,500 mph), while the ISS orbits the Earth at a speed of 27,600 km/h (17,200 mph). As a result, a collision with one of these objects could be catastrophic to the ISS. The station is naturally shielded to withstand impacts from tiny bits of debris and well as micro-meteoroids – and this shielding is divided between the Russian Orbital Segment and the US Orbital Segment.
On the USOS, the shielding consists of a thin aluminum sheet that is held apart from the hull. This sheet causes objects to shatter into a cloud, thereby dispersing the kinetic energy of the impact before it reaches the main hull. On the ROS, shielding takes the form of a carbon plastic honeycomb screen, an aluminum honeycomb screen, and glass cloth, all of which are spaced over the hull.
The ROS’ shielding is less likely to be punctured, hence why the crew moves to the ROS whenever a more serious threat presents itself. But when faced with the possibility of an impact from a larger object that is being tracked, the station performs what is known as a Debris Avoidance Manoeuvre (DAM). In this event, the thrusters on the Russian Orbital Segment fire in order to alter the station’s orbital altitude, thus avoiding the debris.
Future of the ISS:
Given its reliance on international cooperation, there have been concerns in recent years – in response to growing tensions between Russia, the United States, and NATO – about the future of the International Space Station. However, for the time being, operations aboard the station are secure, thanks to commitments made by all of the major partners.
In January of 2014, the Obama Administration announced that it would be extending funding for the US portion of the station until 2024. Roscosmos has endorsed this extension but has also voiced approval for a plan that would use elements of the Russian Orbital Segment to construct a new Russian space station.
Known as the Orbital Piloted Assembly and Experiment Complex (OPSEK), the proposed station would serve as an assembly platform for crewed spacecraft traveling to the Moon, Mars, and the outer Solar System. There have also been tentative announcements made by Russian officials about a possible collaborative effort to build a future replacement for the ISS. However, NASA has yet to confirm these plans.
In April of 2015, the Canadian government approved a budget that included funding to ensure the CSA’s participation with the ISS through 2024. In December of 2015, JAXA and NASA announced their plans for a new cooperative framework for the International Space Station (ISS), which included Japan extending its participation until 2024. As of December 2016, the ESA has also committed to extending its mission to 2024.
The ISS represents one of the greatest collaborative and international efforts in history, not to mention one of the greatest scientific undertakings. In addition to providing a location for crucial scientific experiments that cannot be conducted here on Earth, it is also conducting research that will help humanity make its next great leaps in space – i.e. mission to Mars and beyond!
On top of all that, it has been a source of inspiration for countless millions who dream of going to space someday! Who knows what great undertakings the ISS will allow for before it is finally decommissioned – most likely decades from now?
The ability to take part in long-term space missions is a rare privilege, usually enjoyed by only a handful of men and women within every generation. But that privilege comes with a pretty high price. In addition to all the hard work, training, and sacrifice that is needed to go into space, there are also the health effects of spending prolonged periods in a microgravity environment.
Until recently, the most well-document of these effects were muscle degeneration and loss of bone density. But thanks to a new study released by the Radiological Society of America, it is now understood how microgravity can impair eyesight. This is certainly good news for ISS crews, not to mention the astronauts who will be taking part in long-range missions to Mars and beyond in the near future.
For years, NASA and other space agencies have been seeking to understand how time in space can adversely affect eyesight. Nearly two-thirds of astronauts who have taken part in long-duration missions aboard the International Space Station (ISS) have been diagnosed with Visual Impairment Intracranial Pressure (VIIP) syndrome. Symptoms include blurred vision, flattening at the back of eyeballs, and inflammation of the head of the optic nerves.
Previously, scientists believed that the primary source of VIIP was a shift of vascular fluid toward the upper body that takes place when astronauts spend time in the microgravity of space. But thanks to the new study, which was led by Dr. Noam Alperin and his team of researchers from the University of Miami, the cause of the syndrome has been properly diagnosed.
Dr. Alperin is a professor of radiology and biomedical engineering at the Miller School of Medicine at the University of Miami and the lead author of the study. According to the study he and his colleagues produced – which was presented on Monday, Nov. 28th, at the annual meeting of the Radiological Society of North America in Chicago – the culprit is cerebrospinal fluid (CSF).
This clear fluid is chiefly responsible for cushioning the brain and spinal cord, circulating nutrients and removing waste materials. At the same time, the CSF system is designed to accommodate significant changes in hydrostatic pressures, like when a person goes from lying down or sitting to a standing position. However, this system evolved within Earth’s own gravity environment, and exposing it to microgravity presents unique challenges.
As Dr. Alperin explained in a RSNA press statement, which coincided with the annual meeting:
“People initially didn’t know what to make of it, and by 2010 there was growing concern as it became apparent that some of the astronauts had severe structural changes that were not fully reversible upon return to Earth. On earth, the CSF system is built to accommodate these pressure changes, but in space the system is confused by the lack of the posture-related pressure changes.”
To arrive at this conclusion, Dr. Alperin and his colleague performed a series of before and after MRI scans on seven astronauts who took part in long-duration missions aboard the ISS. The results were compared against nine astronauts who took part in short-duration missions aboard the now-retired Space Shuttle. With the help of some special imaging algorithms, they looked for correlations between changes in CSF volumes and VIIP.
The results of their study Their study, titled “Role of Cerebrospinal Fluid in Spaceflight-Induced Visual Impairment and Ocular Changes“, showed that astronauts who participated in long-duration missions experienced a comparably higher flattening of their eyeballs and protrusions in their optic nerves. These astronauts also had significantly higher post-flight increases in CSF around their optic nerves and in the cavities of the brain where CSF is produced.
This study is both timely and significant, given the growing important of long-duration space missions. At present, it is expected that operations aboard the ISS will last for another decade. One of the most important activities there will be the study of the long-term effects of microgravity on human physiology, which will be intrinsic to preparing astronauts for missions to Mars and other long-range destinations.
In short, identifying the origin of the space-induced ocular changes will help NASA and other space agencies to develop the proper countermeasures to protect the crew from potentially harmful changes to their eyesight. It will also come in handy for private space ventures that are hoping to send human beings on one-way trips to locations where the gravity is lower than on Earth (i.e. the Moon and Mars).
“The research provides, for the first time, quantitative evidence obtained from short- and long-duration astronauts pointing to the primary and direct role of the CSF in the globe deformations seen in astronauts with visual impairment syndrome,” said Alperin. If the ocular structural deformations are not identified early, astronauts could suffer irreversible damage. As the eye globe becomes more flattened, the astronauts become hyperopic, or far-sighted.”
As the old saying goes, “an ounce of prevention is worth a pound of cure”. In addition to having regiments that will help maintain their musculature and bone density, astronauts taking part in long-term missions in the future will also likely need to undergo treatments to ensure their eyesight doesn’t suffer.
Science fiction has told us again and again, we belong out there, among the stars. But before we can build that vast galactic empire, we’ve got to learn how to just survive in space. Fortunately, we happen to live in a Solar System with many worlds, large and small that we can use to become a spacefaring civilization.
This is half of an epic two-part article that I’m doing with Isaac Arthur, who runs an amazing YouTube channel all about futurism, often about the exploration and colonization of space. Make sure you subscribe to his channel.
This article is about colonizing the inner Solar System, from tiny Mercury, the smallest planet, out to Mars, the focus of so much attention by Elon Musk and SpaceX. In the other article, Isaac will talk about what it’ll take to colonize the outer Solar System, and harness its icy riches. You can read these articles in either order, just read them both.
At the time I’m writing this, humanity’s colonization efforts of the Solar System are purely on Earth. We’ve exploited every part of the planet, from the South Pole to the North, from huge continents to the smallest islands. There are few places we haven’t fully colonized yet, and we’ll get to that.
But when it comes to space, we’ve only taken the shortest, most tentative steps. There have been a few temporarily inhabited space stations, like Mir, Skylab and the Chinese Tiangong Stations.
Our first and only true colonization of space is the International Space Station, built in collaboration with NASA, ESA, the Russian Space Agency and other countries. It has been permanently inhabited since November 2nd, 2000. Needless to say, we’ve got our work cut out for us.
Before we talk about the places and ways humans could colonize the rest of the Solar System, it’s important to talk about what it takes to get from place to place.
Just to get from the surface of Earth into orbit around our planet, you need to be going about 10 km/s sideways. This is orbit, and the only way we can do it today is with rockets. Once you’ve gotten into Low Earth Orbit, or LEO, you can use more propellant to get to other worlds.
If you want to travel to Mars, you’ll need an additional 3.6 km/s in velocity to escape Earth gravity and travel to the Red Planet. If you want to go to Mercury, you’ll need another 5.5 km/s.
And if you wanted to escape the Solar System entirely, you’d need another 8.8 km/s. We’re always going to want a bigger rocket.
The most efficient way to transfer from world to world is via the Hohmann Transfer. This is where you raise your orbit and drift out until you cross paths with your destination. Then you need to slow down, somehow, to go into orbit.
One of our primary goals of exploring and colonizing the Solar System will be to gather together the resources that will make future colonization and travel easier. We need water for drinking, and to split it apart for oxygen to breathe. We can also turn this water into rocket fuel. Unfortunately, in the inner Solar System, water is a tough resource to get and will be highly valued.
We need solid ground. To build our bases, to mine our resources, to grow our food, and to protect us from the dangers of space radiation. The more gravity we can get the better, since low gravity softens our bones, weakens our muscles, and harms us in ways we don’t fully understand.
Each world and place we colonize will have advantages and disadvantages. Let’s be honest, Earth is the best place in the Solar System, it’s got everything we could ever want and need. Everywhere else is going to be brutally difficult to colonize and make self-sustaining.
We do have one huge advantage, though. Earth is still here, we can return whenever we like. The discoveries made on our home planet will continue to be useful to humanity in space through communications, and even 3D printing. Once manufacturing is sophisticated enough, a discovery made on one world could be mass produced half a solar system away with the right raw ingredients.
We will learn how to make what we need, wherever we are, and how to transport it from place to place, just like we’ve always done.
Mercury is the closest planet from the Sun, and one of the most difficult places that we might attempt the colonize. Because it’s so close to the Sun, it receives an enormous amount of energy. During the day, temperatures can reach 427 C, but without an atmosphere to trap the heat, night time temperatures dip down to -173 C. There’s essentially no atmosphere, 38% the gravity of Earth, and a single solar day on Mercury lasts 176 Earth days.
Mercury does have some advantages, though. It has an average density almost as high as Earth, but because of its smaller size, it actually means it has a higher percentage of metal than Earth. Mercury will be incredibly rich in metals and minerals that future colonists will need across the Solar System.
With the lower gravity and no atmosphere, it’ll be far easier to get that material up into orbit and into transfer trajectories to other worlds.
But with the punishing conditions on the planet, how can we live there? Although the surface of Mercury is either scorching or freezing, NASA’s MESSENGER spacecraft turned up regions of the planet which are in eternal shadow near the poles. In fact, these areas seem to have water ice, which is amazing for anywhere this close to the Sun.
You could imagine future habitats huddled into those craters, pulling in solar power from just over the crater rim, using the reservoirs of water ice for air, fuel and water.
High powered solar robots could scour the surface of Mercury, gathering rare metals and other minerals to be sent off world. Because it’s bathed in the solar winds, Mercury will have large deposits of Helium-3, useful for future fusion reactors.
Over time, more and more of the raw materials of Mercury will find their way to the resource hungry colonies spread across the Solar System.
It also appears there are lava tubes scattered across Mercury, hollows carved out by lava flows millions of years ago. With work, these could be turned into safe, underground habitats, protected from the radiation, high temperatures and hard vacuum on the surface.
With enough engineering ability, future colonists will be able to create habitats on the surface, wherever they like, using a mushroom-shaped heat shield to protect a colony built on stilts to keep it off the sun-baked surface.
Mercury is smaller than Mars, but is a good deal denser, so it has about the same gravity, 38% of Earth’s. Now that might turn out to be just fine, but if we need more, we have the option of using centrifugal force to increase it. Space Stations can generate artificial gravity by spinning, but you can combine normal gravity with spin-gravity to create a stronger field than either would have.
So our mushroom habitat’s stalk could have an interior spinning section with higher gravity for those living inside it. You get a big mirror over it, shielding you from solar radiation and heat, you have stilts holding it off the ground, like roots, that minimize heat transfer from the warmer areas of ground outside the shield, and if you need it you have got a spinning section inside the stalk. A mushroom habitat.
Venus is the second planet in the Solar System, and it’s the evil twin of Earth. Even though it has roughly the same size, mass and surface gravity of our planet, it’s way too close to the Sun. The thick atmosphere acts like a blanket, trapping the intense heat, pushing temperatures at the surface to 462 C.
Everywhere on the planet is 462 C, so there’s no place to go that’s cooler. The pure carbon dioxide atmosphere is 90 times thicker than Earth, which is equivalent to being a kilometer beneath the ocean on Earth.
In the beginning, colonizing the surface of Venus defies our ability. How do you survive and stay cool in a thick poisonous atmosphere, hot enough to melt lead? You get above it.
One of the most amazing qualities of Venus is that if you get into the high atmosphere, about 52.5 kilometers up, the air pressure and temperature are similar to Earth. Assuming you can get above the poisonous clouds of sulphuric acid, you could walk outside a floating colony in regular clothes, without a pressure suit. You’d need a source of breathable air, though.
Even better, breathable air is a lifting gas in the cloud tops of Venus. You could imagine a future colony, filled with breathable air, floating around Venus. Because the gravity on Venus is roughly the same as Earth, humans wouldn’t suffer any of the side effects of microgravity. In fact, it might be the only place in the entire Solar System other than Earth where we don’t need to account for low gravity.
Now the day on Venus is incredibly long, 243 earth days, so if you stay over the same place the whole time it would be light for four months then dark for four months. Not ideal for solar power on a first glance, but Venus turns so slowly that even at the equator you could stay ahead of the sunset at a fast walk.
So if you have floating colonies it would take very little effort to stay constantly on the light side or dark side or near the twilight zone of the terminator. You are essentially living inside a blimp, so it may as well be mobile. And on the day side it would only take a few solar panels and some propellers to stay ahead. And since it is so close to the Sun, there’s plenty of solar power. What could you do with it?
The atmosphere itself would probably serve as a source of raw materials. Carbon is the basis for all life on Earth. We’ll need it for food and building materials in space. Floating factories could process the thick atmosphere of Venus, to extract carbon, oxygen, and other elements.
Heat resistant robots could be lowered down to the surface to gather minerals and then retrieved before they’re cooked to death.
Venus does have a high gravity, so launching rockets up into space back out of Venus’ gravity well will be expensive.
Over longer periods of time, future colonists might construct large solar shades to shield themselves from the scorching heat, and eventually, even start cooling the planet itself.
The next planet from the Sun is Earth, the best planet in the Solar System. One of the biggest advantages of our colonization efforts will be to get heavy industry off our planet and into space. Why pollute our atmosphere and rivers when there’s so much more space… in space.
Over time, more and more of the resource gathering will happen off world, with orbital power generation, asteroid mining, and zero gravity manufacturing. Earth’s huge gravity well means that it’s best to bring materials down to Earth, not carry them up to space.
However, the normal gravity, atmosphere and established industry of Earth will allow us to manufacture the lighter high tech goods that the rest of the Solar System will need for their own colonization efforts.
But we haven’t completely colonized Earth itself. Although we’ve spread across the land, we know very little about the deep ocean. Future colonies under the oceans will help us learn more about self-sufficient colonies, in extreme environments. The oceans on Earth will be similar to the oceans on Europa or Enceladus, and the lessons we learn here will teach us to live out there.
As we return to space, we’ll colonize the region around our planet. We’ll construct bigger orbital colonies in Low Earth Orbit, building on our lessons from the International Space Station.
One of the biggest steps we need to take, is understanding how to overcome the debilitating effects of microgravity: the softened bones, weakened muscles and more. We need to perfect techniques for generating artificial gravity where there is none.
The best technique we have is rotating spacecraft to generate artificial gravity. Just like we saw in 2001, and The Martian, by rotating all or a portion of a spacecraft, you can generated an outward centrifugal force that mimics the acceleration of gravity. The larger the radius of the space station, the more comfortable and natural the rotation feels.
Low Earth Orbit also keeps a space station within the Earth’s protective magnetosphere, limiting the amount of harmful radiation that future space colonists will experience.
Other orbits are useful too, including geostationary orbit, which is about 36,000 kilometers above the surface of the Earth. Here spacecraft orbit the Earth at exactly the same rate as the rotation of Earth, which means that stations appear in fixed positions above our planet, useful for communication.
Geostationary orbit is higher up in Earth’s gravity well, which means these stations will serve a low-velocity jumping off points to reach other places in the Solar System. They’re also outside the Earth’s atmospheric drag, and don’t require any orbital boosting to keep them in place.
By perfecting orbital colonies around Earth, we’ll develop technologies for surviving in deep space, anywhere in the Solar System. The same general technology will work anywhere, whether we’re in orbit around the Moon, or out past Pluto.
When the technology is advanced enough, we might learn to build space elevators to carry material and up down from Earth’s gravity well. We could also build launch loops, electromagnetic railguns that launch material into space. These launch systems would also be able to loft supplies into transfer trajectories from world to world throughout the Solar System.
Earth orbit, close to the homeworld gives us the perfect place to develop and perfect the technologies we need to become a true spacefaring civilization. Not only that, but we’ve got the Moon.
The Moon, of course, is the Earth’s only natural satellite, which orbits us at an average distance of about 400,000 kilometers. Almost ten times further than geostationary orbit.
The Moon takes a surprising amount of velocity to reach from Low Earth Orbit. It’s close, but expensive to reach, thrust speaking.
But that fact that it’s close makes the Moon an ideal place to colonize. It’s close to Earth, but it’s not Earth. It’s airless, bathed in harmful radiation and has very low gravity. It’s the place that humanity will learn to survive in the harsh environment of space.
But it still does have some resources we can exploit. The lunar regolith, the pulverized rocky surface of the Moon, can be used as concrete to make structures. Spacecraft have identified large deposits of water at the Moon’s poles, in its permanently shadowed craters. As with Mercury, these would make ideal locations for colonies.
Our spacecraft have also captured images of openings to underground lava tubes on the surface of the Moon. Some of these could be gigantic, even kilometers high. You could fit massive cities inside some of these lava tubes, with room to spare.
Helium-3 from the Sun rains down on the surface of the Moon, deposited by the Sun’s solar wind, which could be mined from the surface and provide a source of fuel for lunar fusion reactors. This abundance of helium could be exported to other places in the Solar System.
The far side of the Moon is permanently shadowed from Earth-based radio signals, and would make an ideal location for a giant radio observatory. Telescopes of massive size could be built in the much lower lunar gravity.
We talked briefly about an Earth-based space elevator, but an elevator on the Moon makes even more sense. With the lower gravity, you can lift material off the surface and into lunar orbit using cables made of materials we can manufacture today, such as Zylon or Kevlar.
One of the greatest threats on the Moon is the dusty regolith itself. Without any kind of weathering on the surface, these dust particles are razor sharp, and they get into everything. Lunar colonists will need very strict protocols to keep the lunar dust out of their machinery, and especially out of their lungs and eyes, otherwise it could cause permanent damage.
Although the vast majority of asteroids in the Solar System are located in the main asteroid belt, there are still many asteroids orbiting closer to Earth. These are known as the Near Earth Asteroids, and they’ve been the cause of many of Earth’s great extinction events.
These asteroids are dangerous to our planet, but they’re also an incredible resource, located close to our homeworld.
The amount of velocity it takes to get to some of these asteroids is very low, which means travel to and from these asteroids takes little energy. Their low gravity means that extracting resources from their surface won’t take a tremendous amount of energy.
And once the orbits of these asteroids are fully understood, future colonists will be able to change the orbits using thrusters. In fact, the same system they use to launch minerals off the surface would also push the asteroids into safer orbits.
These asteroids could be hollowed out, and set rotating to provide artificial gravity. Then they could be slowly moved into safe, useful orbits, to act as space stations, resupply points, and permanent colonies.
There are also gravitationally stable points at the Sun-Earth L4 and L5 Lagrange Points. These asteroid colonies could be parked there, giving us more locations to live in the Solar System.
The future of humanity will include the colonization of Mars, the fourth planet from the Sun. On the surface, Mars has a lot going for it. A day on Mars is only a little longer than a day on Earth. It receives sunlight, unfiltered through the thin Martian atmosphere. There are deposits of water ice at the poles, and under the surface across the planet.
Martian ice will be precious, harvested from the planet and used for breathable air, rocket fuel and water for the colonists to drink and grow their food. The Martian regolith can be used to grow food. It does have have toxic perchlorates in it, but that can just be washed out.
The lower gravity on Mars makes it another ideal place for a space elevator, ferrying goods up and down from the surface of the planet.
Unlike the Moon, Mars has a weathered surface. Although the planet’s red dust will get everywhere, it won’t be toxic and dangerous as it is on the Moon.
Like the Moon, Mars has lava tubes, and these could be used as pre-dug colony sites, where human Martians can live underground, protected from the hostile environment.
Mars has two big problems that must be overcome. First, the gravity on Mars is only a third that of Earth’s, and we don’t know the long term impact of this on the human body. It might be that humans just can’t mature properly in the womb in low gravity.
Researchers have proposed that Mars colonists might need to spend large parts of their day on rotating centrifuges, to simulate Earth gravity. Or maybe humans will only be allowed to spend a few years on the surface of Mars before they have to return to a high gravity environment.
The second big challenge is the radiation from the Sun and interstellar cosmic rays. Without a protective magnetosphere, Martian colonists will be vulnerable to a much higher dose of radiation. But then, this is the same challenge that colonists will face anywhere in the entire Solar System.
That radiation will cause an increased risk of cancer, and could cause mental health issues, with dementia-like symptoms. The best solution for dealing with radiation is to block it with rock, soil or water. And Martian colonists, like all Solar System colonists will need to spend much of their lives underground or in tunnels carved out of rock.
In addition to Mars itself, the Red Planet has two small moons, Phobos and Deimos. These will serve as ideal places for small colonies. They’ll have the same low gravity as asteroid colonies, but they’ll be just above the gravity well of Mars. Ferries will travel to and from the Martian moons, delivering fresh supplies and sending Martian goods out to the rest of the Solar System.
We’re not certain yet, but there are good indicators these moons might have ice inside them, if so that is an excellent source of fuel and could make initial trips to Mars much easier by allowing us to send a first expedition to those moons, who then begin producing fuel to be used to land on Mars and to leave Mars and return home.
According to Elon Musk, if a Martian colony can reach a million inhabitants, it’ll be self-sufficient from Earth or any other world. At that point, we would have a true, Solar System civilization.
Now, continue on to the other half of this article, written by Isaac Arthur, where he talks about what it will take to colonize the outer Solar System. Where water ice is plentiful but solar power is feeble. Where travel times and energy require new technologies and techniques to survive and thrive.
The International Space Station has provided astronauts and space agencies with immense opportunities for research during the decade and a half that it has been in operation. In addition to studies involving meteorology, space weather, materials science, and medicine, missions aboard the ISS has also provided us with valuable insight into human biology.
For example, studies conducted aboard the ISS’ have provided us with information about the effects of long-term exposure to microgravity. And all the time, astronauts are pushing the limits of how long someone can healthily remain living under such conditions. One such astronauts is Jeff Williams, the Expedition 48 commander who recently established a new record for most time spent in space.
This record-breaking feat began back in 2000, when Williams spent 10 days aboard the Space Shuttle Atlantis for mission STS-101. At the time, the International Space Station was still under construction, and as the mission’s flight engineer and spacewalker, Williams helped prepare the station for its first crew.
This was followed up in 2006, where Williams’ served as part of Expedition 13 to the ISS. The station had grown significantly at this point with the addition of Russian Zvezda service module, the U.S. Destiny laboratory, and the Quest airlock. Numerous science experiments were also being conducted at this time, which included studies into capillary flow and the effects of microgravity on astronauts’ central nervous systems.
During the six months he was aboard the station, Williams was able to get in two more spacewalks, set up additional experiments on the station’s exterior, and replaced equipment. Three years later, he would return to the station as part of Expedition 21, then served as the commander of Expedition 22, staying aboard the station for over a year (May 27th, 2009 to March 18th, 2010).
By the time Expedition 48’s Soyuz capsule launched to rendezvous with the ISS on July 7th, 2016, Williams had already spent more than 362 days in space. By the time he returns to Earth on Sept. 6th, he will have spent a cumulative total of 534 days in space. He will have also surpassed the previous record set by Scott Kelly, who spent 520 days in space over the course of four missions.
On Wednesday, August 24th, the International Space Station raised its orbit ahead of Williams’ departure. Once he and two of his mission colleagues – Oleg Skripochka and Alexey Ovchinin – undock in their Soyuz TMA-20M spacecraft, they begin their descent towards Kazakhstan, arriving on Earth roughly three and a half hours later.
Former astronaut Scott Kelly was a good sport about the passing of this record, congratulating Williams in a video created by the Johnson Space Center (see below). Luckily, Kelly still holds the record for the longest single spaceflight by a NASA astronaut – which lasted a stunning 340 days.
And Williams may not hold the record for long, as astronaut Peggy Whitson is scheduled to surpass him in 2017 during her next mission (which launches this coming November). And as we push farther out into space in the coming years, mounting missions to NEOs and Mars, this record is likely to be broken again and again.
In the meantime, Williams and his crew will continue to dedicate their time to a number of crucial experiments. In the course of this mission, they have conducted research into human heart function, plant growth in microgravity, and executed a variety of student-designed experiments.
Like all research conducted aboard the ISS, the results of this research will be used to improve health treatments, have numerous industrial applications here on Earth, and will help NASA plan mission farther into space. Not the least of which will be NASA’s proposed (and rapidly approaching) crewed mission to Mars.
In addition to spending several months in zero-g for the sake of the voyage, NASA will need to know how their astronauts will fair when conducting research on the surface of Mars, where the gravity is roughly 37% that of Earth (0.376 g to be exact).
And be sure to enjoy this video of Scott Kelly congratulating Williams on his accomplishment, courtesy of the Johnson Space Center: