The International Space Station

Why do we need the ISS?

Image credit: NASA

The International Space Station is the most expensive and most complex engineering project ever. What are the societal benefits of maintaining an orbital outpost that we mere mortals will never get to visit?

In November 2020, the International Space Station celebrated 20 years of its permanent human habitation. A major milestone for the world of astronautics and, as the world’s space agencies say, for humanity itself.

The assembly of the station began in late 1998 with the launch of the Russian-built module Zarya and the American Unity. It was completed in the early 2010s after the arrival of Tranquility with its trademark Earth-facing viewing platform Cupola.

Consisting of 16 pressurised modules and a lot of supporting hardware, the station covers the size of a football pitch. Its construction stretched the technical as well as political skills of the partnering space agencies. With a construction cost of nearly £90bn and an annual running cost of nearly £3bn, it also stretched their budgets. The taxpayer, afflicted with rising house prices, costly education and stagnant wages, might feel entitled to ask – what are we getting in return?

According to the European Space Agency (ESA), maintaining the ISS is rather a bargain for the public. The £90bn construction cost has been, ESA says, spread over a period of almost 30 years and all the participating countries, which include the USA, Russia, the member states of ESA, Canada, and Japan. Thus, every European, ESA says, contributes about one euro per year for the station’s upkeep.

What are we getting in return for investing a somewhat modest amount into a permanent space station?

According to Stefaan de Mey, senior strategy officer for human and robotic exploration at ESA, every euro invested into space exploration activities in general generates three euros of economic return in the short term. The overall economic benefits, however, are difficult to estimate.

“Apart from the immediate benefits for the industry that works on these projects, there are technology transfer opportunities,” de Mey says. “For example, minus-80-degree freezers originally developed to store scientific samples at the space station are now used on liquefied natural gas tankers to re-liquefy evaporating gas. That saves the gas but also prevents CO2 emissions. However, the timescales for these applications to develop is much longer.”

In addition to scientific research, the challenges posed by the construction of the space station, as well as by maintaining a habitable environment inside, have already produced solutions that have since trickled into down-to-Earth applications. Here are some of the most interesting or promising discoveries that have come out of the orbiting laboratory.

Smart drug delivery and better medicine 

In December 2020, ESA announced it would send the Covid-19 drug Remdesivir to the space station to study how it interacts with its delivery substance in order to improve treatment efficiency.

The research will use one of the protein crystal growth facilities on the station. Studying crystal growth of various organic proteins is one of the promising areas of ISS research. In the absence of gravity, protein crystals grow bigger and develop more complex and purer structures. By imaging these space-grown crystals back on the Earth, scientists gain new insights into the working of various proteins involved in the development of diseases such as muscular dystrophy or Alzheimer’s. Subsequently, they can design more efficient treatments or improve the existing ones.

Nasa says that using space-grown crystals decreases overall research costs for pharmaceutical companies, as the detailed study of crystals enabled by the size and quality of the crystals grown in space allows more accurate predictions of the drugs’ behaviour.

One such drug, developed with the help of the space station, is Prolia, one of the most used osteoporosis treatments in the United States.

There are even more disruptive medical innovations expected from the space station research. A team from Houston Methodist Research Institute led by Alessandro Grattoni uses the microgravity environment to study how fluids flow through very small channels. The discipline, called nanofluidics, holds promise for the development of drug delivery implants that would dispense pharmaceuticals in a targeted way. Instead of swallowing pills or administering injections, which according to the researchers causes a temporary overdose, the nanofluidic systems would mimic the body’s natural behaviour and release molecules where they are needed and in the right amount. The subcutaneous implants could even be remotely controlled.

The team’s first refillable drug-releasing implant, a treatment designed to prevent at-risk individuals from catching HIV, might be approved for use in 2021, according to Nasa.

Water recycling and air purification

The effort to keep humans alive indefinitely at 400km above the Earth has produced some ingenious solutions that are finding secondary purposes on the planet itself.

While the crews of short-term missions, such as those of the Apollo or Gemini era, could carry most of their water and oxygen with them, permanent human occupancy of the ISS requires sophisticated systems capable of reliably recycling these critical consumables.

The Environmental Control and Life Support System used to recycle water and breathable air consists of the water recovery system (WRS) and the oxygen generation system (OGS). WRS recycles up to 93 per cent of water used at the space station. That includes astronauts’ urine, water used in lab experiments and vapour condensed inside the crew’s quarters.

The system has been adapted on the Earth to help villages in developing countries struck by drought or well contamination, but also, for example, to reduce water consumption at a Dutch brewery. As de Mey explains: “The Koningshoeven Trappist Abbey installed the adapted space station water-recycling technology in 2019 and now reuses 80 per cent of the water required for the brewing process. They say that not a drop of water leaves the Abbey unless it’s in the form of beer.”

The agencies operating the station are constantly looking for improvements. Innovative companies can thus use the station as a development and test bed to take interesting concepts through the technology maturation process towards commercialisation.

A new type of filtration membrane called Aquaporin has been tested by ESA and Nasa as a possible replacement for the WRS multi-filtration beds, which have to be changed every 90 days.

Aquaporin is based on ‘forward osmosis’, relying on similar principles to plant roots and kidneys. Unlike reverse osmosis, commonly used for water purification and desalination, forward osmosis needs no additional source of energy to push polluted liquid through a filtering membrane.

Instead, the system puts salt water or a sugar solution on one side of the membrane and the polluted water on the other. Principles of physics dictate that the salt or sugar has to spread evenly throughout the water, but since neither can pass through the filter, they have to draw all the liquid to one side of the membrane leaving all the pollutants on the other. Tests at the Nasa Ames Research Centre showed that the technology removes even semi-volatile contaminants.

Aquaporin A/S, the Danish company behind the system, has entered partnerships with several wastewater companies looking for new ways to remove troublesome pollutants such as micro­plastics. A study by Biofos found that Aquaporin can remove up to 95 per cent of microplastics in wastewater and do it more cost-effectively than conventional systems.

From space robots to medical robots

The 15m-long Canadarm has been a symbol of space robotics since the Space Shuttle era. Used in the iconic operation to release the Hubble Space Telescope and again to repair it later, the manipulator arm also played a key role in the assembly of the ISS.

Canada, the arm’s developer, has flexed its robotics muscle even further with the creation of Dextre (the Special Purpose Dexterous Manipulator). This 3.7m-tall remotely controlled programmable robot with 3.5m-long arms serves as the station’s handyman. Equipped with lights, video cameras, a tool platform and four tool holders, Dextre can change the station’s batteries, replace the outdoor cameras, and move around to where help is needed.

Canadian technology firm MDA used the experience gained from Canadarm and Dextre to create a range of medical robots with novel capabilities, according to the Canadian Space Agency.

The neuroArm, the world’s first medical robot that can operate inside magnetic resonance tunnels, allows surgeons to perform the most precise surgeries on people’s brains. The MRI enables the surgeon to see more clearly where the malignant tissue ends and remove all of it to minimise the risk of a regrowth. The robot was first used in 2008 to remove a tumour from the brain of a 21-year-old woman.

A later device, the Image-Guided Autonomous Robot (IGAR), entered clinical trials in 2015, according to Nasa. The robot, also capable of operating inside an MRI machine, was originally intended for remotely guided surgeries aboard the ISS. It has, however, been trained to perform minimally invasive and ultra-precise breast cancer procedures. Like Dextre, IGAR can be programmed and then act completely autonomously.

In 2015, MDA took part in the development of a robotic digital microscope that uses similar software to the Canadarm2. The device, used for spinal and brain surgeries, automatically follows every move of the surgeon, and allows him or her to seamlessly monitor their actions in great detail via large screens.

Cool flames

After decades of studies on the ground, scientists thought that nothing could surprise them about combustion processes anymore. A big mistake. All it took was to fly a combustion experiment in space and an entirely new phenomenon was discovered that could potentially lead to major improvements in combustion technology in the future.

The Flame Extinguishing Experiments (FLEX and FLEX2), flown in 2009 and 2017 respectively, found that when a visibly burning droplet of fuel extinguishes, an invisible, cooler combustion process continues. The FLEX experiment revealed that the fire continues to burn imperceptibly at 600°C compared to the visible burning at 1,400°C, according to Nasa. The second generation FLEX2 uncovered an even cooler second invisible flame phenomenon at about 200°C.

The work led to a new type of fire extinguisher, but researchers expect that these discoveries could also help improve the understanding and numerical modelling of combustion processes that could in turn lead to the development of more efficient combustion engines, says Nasa. Increased mileage but also reduced generation of pollutants could be the future benefits stemming from this new insight.

Growing organs in space

According to Stefaan de Mey at ESA, the space station is the perfect environment for growing artificial organs.

A 2016 experiment successfully grew endothelial cells, the type of cells that form the inner lining of human blood vessels, in the microgravity environment. Interestingly, unlike cells grown on the Earth, the cells in the Spheroids experiment naturally formed tubular structures, essentially miniature blood vessels, without needing any external support.

“If you want to grow human tissue in a three-dimensional structure or an actual human organ on the Earth, you have a problem with the gravity,” de Mey says. “You need to use some sort of a scaffold to support the form otherwise the tissue collapses. You don’t need that in space.”

The scaffold material, de Mey added, may interfere with the cells and have a negative effect on them. But in the weightless environment, the cells naturally organised themselves as they would inside a human body.

Tissue engineering is one of the holy grails of modern medicine, promising hope to patients with life-threatening conditions. The research is still in its early stages but could in the future help patients suffering from common conditions including arterial sclerosis or diabetes.

“It’s potentially much easier to grow organs in microgravity than on the Earth,” de Mey adds. “Those experiments are meant to start our understanding how to do that. It’s far from finished. It will still take a lot of time to really come to a useable process but it’s quite promising.” 

Timeline: The ISS 

25 January 1984: President Ronald Reagan directs Nasa to build the ISS.

20 November 1998: First ISS segment launches: a Russian module named Zarya (‘sunrise’).

4 December 1998: Unity, the first US-built component of the ISS launches – the first Space Shuttle mission dedicated to assembly of the station.

2 November 2000: Astronaut Bill Shepherd and cosmonauts Yuri Gidzenko and Sergei Krikalev become the first crew to reside on the station.

7 February 2001: US laboratory module Destiny added to the station.

2005: Congress designates US lab module as a National Laboratory.

7 February 2008: The European Space Agency’s Columbus Laboratory becomes part of the station.

11 March 2008: The first Japanese Kibo laboratory module becomes part of the station.

14 November 2008: Nasa’s Water Recovery and Management System launches for installation in the ISS’s US Tranquility module.

29 May 2009: ISS’s long-duration crew increases from three to six for the first time with the docking of Russia’s Soyuz TMA-15 spacecraft.

25 May 2012: A SpaceX Dragon capsule becomes first commercial spacecraft to reach the ISS.

13 March 2013: Chris Hadfield becomes first Canadian to serve as ISS commander.

9 March 2014: Koichi Wakata becomes the first Japanese man to serve as ISS commander.

27-8 August 2016: Nasa astronaut and microbiologist Kathleen Rubins becomes the first person to sequence DNA from space.

6 December 2020: Latest SpaceX Dragon resupply spacecraft launch to ISS; sends Nasa science and research resources and delivers new airlock to station.

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