Challenges, Opportunities, and Moon Shots
For the young and young at heart, there is no denying helium is fun. Has anyone been to a birthday party where someone didn’t untie a balloon, inhale the colourless, odourless and non-flammable gas, and start squeaking? Well, as entertaining as helium is, its practical applications go far beyond gags and lighter-than-air balloons. And before too long, party giggles and more may be coming by way of the moon.
Discovered in the spectrum of the Sun’s corona by French astronomer Pierre Janssen in 1868, helium was later named after helios – the Greek word for sun – by British chemist Edward Frankland and British astronomer Sir Joseph Norman Lockyer.
The second element on the periodic table, helium (He) is one of seven ‘noble’ gases on the table. The lightest of all gases except for hydrogen, helium shares many other of hydrogen’s properties (it’s odourless, colorless, and tasteless) with one enormous exception: helium is completely non-flammable.
The notorious flammability of hydrogen tragically brought the Depression-era dream of luxury dirigible air travel to a halt with the explosion and fiery crash of the Hindenburg in New Jersey on May 6, 1937. While there are many theories about the cause of the fire, one thing is certain: if the Hindenburg had been using helium, it would not have burnt.
A gas of many uses
Chemically inert, helium is the hardest gas to liquefy, which makes it ideal for many applications, including as a refrigerant. When it is cooled to just below its boiling point of -452 degrees Fahrenheit (-269 degrees Celsius), liquid helium becomes helium II.
Also known as a superfluid, it takes on a jaw-dropping ability to flow without friction. In other words, if you spin it around in a cup it will keep spinning… and spinning… and spinning, and can literally climb up and over the edge of containers. With no freezing point and zero viscosity, it can seep through the tiniest cracks.
Given its many unique properties, helium is in growing demand, and governments and research laboratories are among the biggest consumers of the noble gas.
Along with liquid nitrogen, one of helium’s biggest applications – in liquid form – is in cryogenics. Defined by Merriam-Webster as “a branch of physics that deals with the production and effects of very low temperatures,” cryogenics has many uses: In the food industry, it helps keep food fresher longer without the addition of preservatives or chemicals. In the space industry, cryoelectronics are used to make rocket fuel, and for electrons to move more freely. In medicine, cryosurgery is used to freeze and destroy skin tumours, while cryobiology can preserve organs, cells, and embryos.
From rocketry to welding
With about 92 percent of the lifting power of hydrogen and none of the risks of explosion, helium is found in high-risk industries such as the space sector and welding.
Regularly used to stiffen rockets, helium has been used for autogenous pressurization on the Space Shuttle, where it pressurizes liquid propellants. Being stable and non-reactive, it is ideal for arc-welding light metals, including magnesium and aluminum.
After hydrogen, helium is the second-most abundant element in the universe. Despite this, it is rare here on Earth, with much of it extracted, along with natural gas, from the Hugoton Gas Field which extends across Kansas, Oklahoma, and Texas. Compressed and shipped in small quantities in steel cylinders, helium can also be transported in insulated containers in liquid form.
Despite its many uses in science, medicine, industry and the space sector, America’s private natural gas companies were not required to recover helium freed as a by-product of their activities between 1973 and 1980, nor did the U.S. government store it during that period, with billions of cubic feet lost every year. This was surprising, considering the Helium Act of 1925, “An Act Authorizing the conservation, production, and exploitation of helium gas, a mineral resource pertaining to the national defense, and to the development of commercial aeronautics, and for other purposes.”
Amended several times over the years, the Helium Privatization Act of 1996 was controversial, ordering the American government to sell a good part of the National Helium Reserve – a reserve of over 1 billion cubic meters of helium gas. Critics called it a fiasco, with the sale price far lower than the gas’s market price. Despite the criticism, the bill wasn’t amended until 2013.
Increasingly rare on Earth
The world is running out of its supplies of helium, and the situation will affect much more than just birthday balloons. (Although last year, with helium in short supply, many party-supply stores ran out of the gas, while others increased prices up to 135 percent.)
This shortage is not good news for the planet’s medical, scientific, and space sectors, since helium is vital to cooling Magnetic Resonance Imaging (MRI) superconducting magnets used in making solar cells, in supersonic wind tunnels, rocket engines, and many other applications.
This shortage has led to the genuine possibility of looking to outer space for Earth’s helium supply. Over 30 years ago, it was estimated that the surface regolith (loose soil, dust and rocks) on the moon contains a million tons of helium-3. As challenging and costly as mining the moon would be, scientists from the University of Wisconsin’s Institute of Fusion Technology have been investigating pros and cons.
With the potential of being used as a nuclear fusion fuel source, it was determined that “mining it would be a profitable undertaking: the energy produced by the helium-3 would be 250 times greater than that needed to extract this resource from the Moon and transport it to Earth, where the lunar reserves of helium-3 could supply human needs for centuries,” according to a March 2019 article by OpenMind.
Discovered in 1939, helium-3 has been eyed as a source of energy for years, particularly in nuclear fusion. Although requiring extremely high temperatures, helium-3 atoms can release significant energy without making other materials radioactive.
One of the reasons for the scarcity of helium-3 on Earth is, ironically, what protects us, namely our atmosphere. Absorbing ultraviolet solar radiation, the Earth’s atmosphere is approximately 300 miles (480 kilometers) thick, becoming much thinner the higher we go, and eventually disappearing. The moon does not possess a similar shielding atmosphere, and throughout its existence has absorbed tremendous amounts of helium-3.
As with all proposals of mining in space, harvesting helium-3 from the moon presents many challenges, and will require plenty of expertise – and money.
Taking mining to the Moon
The European Space Agency (ESA) – an intergovernmental body consisting of 22 member states – and ArianeGroup, “as prime contractor of a consortium of ArianeGroup, Space Application Services and PTScientists,” signed an agreement to study and make ready ESA’s planned in-space, in-situ resource-use (ISRU) mission.
While focused on the moon’s regolith, the mission will gather, process, store, and use “materials found or produced on other celestial bodies (Moon, Mars, asteroids, etc.) to replace materials that would otherwise be brought from Earth,” according to privately-held Berlin-based Planetary Transportation Systems GmbH (PTS).
Describing itself as a new-space company, PTS’s “aim is to bring down the cost of space exploration and democratize access to the Moon.” To achieve its goal, the company is dedicated to developing dependable systems that will get payloads to the right locations, and has created a spacecraft that can deliver two rovers (up to 300 kg or 661 lbs. of payload) to the moon’s barren surface.
Like other space mining proposals which see minerals used on planets to sustain human life (iron, titanium, aluminum and others on Mars, for example), helium-3 would be transported to Earth, and used on the moon to support people and mining machinery.
As well as Europe, other countries, including India, have expressed an interest in mining the moon. And as our supply of helium dwindles, the greater the likelihood becomes that the harvesting of other planets for helium will become a reality in the very near future.