Proposal: Freeing the Moon From the Sun’s Solar Radiation With Satellites and Superconductors
How we can leverage space technologies to permanently live on the Moon
Abstract
Since we began constructing rockets to shoot up into space, our ultimate goal was to transition the human race to becoming a multi-planetary species. After all, it’s in our DNA. Travel, find new worlds, and explore the limitless bounds of space. We thought Mars would be a nice place to settle down, but before we master Mars, we need to get to the Moon. We need to prove that lunar habitation is a possibility before we even consider sending our bravest astronauts to the lifeless husk that is Mars. We thought that we should be able to achieve lunar habitation rather quickly but one obstacle in particular stands in our way: the Sun’s ultraviolet (UV) radiation. This paper outlines the challenges of Moon habitation and proposes a potential solution to the effects of the dreaded solar radiation: a network of satellites and superconductors to monitor and deflect the solar wind’s ultraviolet radiation. This solution keeps our astronauts and technologies safe on the Moon while enforcing future partially terraformed lunar habitats in place.
Outline of Proposal
1 — Introduction
2 — Background of magnetic fields in space
2.1 Why do magnetic fields need to be generated in space?
2.2 How magnetic fields are generated naturally
2.3 Differences: natural vs. artificial magnetic fields
2.4 Similarities: natural vs. artificial magnetic fields
3 — Superconductors and terraformation
3.1 What are superconductors and what are they made of
3.2 Terraforming vs. partial terraforming
3.3 Purpose
4 — Artificial satellites
4.1 Artificial satellites vs. natural satellites
4.2 Purpose
5 — Superconducting ring functions and technologies
5.1 Appearance, placement, and size of superconducting rings
5.2 Power supply for superconducting rings and materials used
5.3 Labeled diagram
6 — Artificial satellite functions and technologies
6.1 Solar sensor payload
6.2 Antenna
6.3 Control system
6.4 Thermal control system and temperature-resistant materials
6.5 Telemetry control system
6.6 Labeled diagrams
7 — Conclusion
1 — Introduction
Solar radiation has been one of the biggest obstacles astronauts face after leaving the safety of the Earth and is one of the main reasons why we cannot sustain life on other planets. What we predict will happen to astronauts, is they will be able to live on another celestial body, like the Moon, for long, which poses the question: How much radiation are astronauts subject to while living on the Moon, going about their day-to-day lives?
This mystery was explained soon following the publication of the findings of an experiment by China’s Chang’E 4 lander in the journal Science Advances by a Chinese-German collaboration. The scientists discovered that the radiation exposure on the Moon is 1,369 microsieverts per day, which is around 2.6 times more than the crew’s daily dose on the International Space Station. This was, obviously, not the answer scientists were hoping for.
However, there is hope. Superconductors are becoming more and more popular in the way that we think about everything from the power grid to the future of Space Tech. It was later found that the magnetic field that superconductors produce can divert solar UV radiation. No one has yet to draw up plans for how to actually act on this and make a radiation-less lunar habitat a possibility.
This proposal covers how to go about activating a network of satellites and superconducting rings orbiting the Moon to solve the solar UV radiation problem completely, once and for all.
2 — Background of magnetic fields in space
2.1 Why do magnetic fields need to be generated in space?
Two words: solar wind. What happens is the charged protons and electrons from the Sun’s outer atmosphere (a.k.a. the corona) heat up until the Sun’s gravity is no longer able to hold them down.
They then accelerate to extremely high speeds in a flow of particles known as the solar wind, reaching speeds up to 80% of the speed of light. On Earth, the negative effects of the solar wind are significantly reduced due to the magnetosphere (the naturally generated magnetic field around our planet that deflects the solar wind). However, the Moon does not have this kind of protection. The solar wind, when released into space can cause all sorts of problems for humans and the equipment that sustains missions on other moons and planets.
Impacts on human health caused by the UV radiation from the solar wind:
- Radiation poisoning/sickness
- Increased cancer rates
- Effects on the central nervous system
- Increased risk of heart disease and other cardiovascular diseases
- Eye damage and vision problems
- Higher mortality rates
- Mutations within the human genome
Other impacts of the UV radiation from the solar wind:
- Communication obstruction
- Failure or malfunctions of equipment
- Affects the precision of scientific experiments occurring on the Moon
2.2 How magnetic fields are generated naturally
The Earth is not the only planet in our solar system to have its own natural magnetic field. Jupiter, Saturn, Uranus, and Neptune actually all have magnetic fields stronger than Earth’s (with Jupiter’s field being the strongest, which makes sense given the planet’s size).
The function of magnetic fields can be explained by the Dynamo effect. The Dynamo effect (a.k.a. the Dynamo theory) is the scientific theory that is the most likely for why our Earth — and many other celestial bodies — have a magnetic field surrounding them. The theory says that with the movement of a material that can conduct electricity (eg. liquid metal or any other conductive material) within a planet or star’s core, an electric current will be generated, one that creates a magnetic field. For a magnetic field to be generated naturally by a celestial body, there are three necessary things according to the Dyanmo theory:
(1) an electrically conductive fluid medium (a fluid able to conduct electricity)
(2) kinetic energy provided by planetary rotation (a build-up of energy because of a planet’s rotation)
(3) an internal source of energy that powers convective motions (something from the core/inside of a planet providing energy for a motion where the warmer liquids rise and the cooler ones sink).
Our planet has all these things, which is why it is able to generate a magnetic field naturally. If we can simulate these conditions on or near another celestial body we will be able to artificially generate a magnetic field in space.
2.3 Differences: natural vs. artificial magnetic fields
Differences:
- Creation of fields
When looking at the creation of the two, the artificial one would obviously be man-made, constructed with superconductors, and the natural one would exist in space under the necessary conditions stated above by the Dynamo effect.
- Weak spots
Since Earth’s magnetic field enters and exits through our planet’s north and south poles, this leaves these two areas exposed to the solar wind and sometimes solar radiation can escape through these two hidden entrances. With an artificial magnetic field that overlaps such as the proposed design, there will be no way for the solar wind to penetrate the field, leaving no radiation escaping through to the lunar surface.
- Pole reversal
As of today, the Earth’s magnetic field goes in through the North and exits through the South. However, this will likely change. This is because the Earth’s magnetic field has flipped quite a few times so far and will likely continue to do the same thing for the rest of its existence. This is a natural phenomenon called pole reversal. Every 200 000 to 300 000 years the North and South poles of our planet’s magnetic field flip, despite the fact that it has been twice as long since the previous reversal. This means that if you were alive 800 000 years ago, your compass would have pointed South instead of North. Pole reversal is an event that only happens with natural magnetic fields and not artificial ones.
2.4 Similarities: natural vs. artificial magnetic fields
- Unit of measurement
The strength of both natural and artificial magnetic fields can be expressed in the unit of tesla (T), or microtesla (µT). Another commonly used unit is gauss (G), or miligauss (mG). 10 000 gauss is equivalent to the strength of one tesla. The Earth’s magnetic field’s magnetic flux density is about 50 microtesla (or 0.00005 tesla). To read the strength of a magnetic field not on the celestial scale, you can also use a gaussmeter (a hand-held instrument capable of measuring a magnetic field in gauss.
- Energy sources
The magnetic field of the Earth would be different from one generated artificially, but they both need an energy source. For the Earth, that energy source comes from deep within its crust (internal energy leftover from the creation of our planet billions of years ago).
For an artificial magnetic field generated by superconductors, there is an energy source, however, it doesn’t occur naturally in space.
Additionally, the energy that they do generate is preserved better. This is because superconductors have zero electrical resistance (0 Ω) and they can transmit electricity without producing any waste.
3 — Superconductors and terraformation
3.1 What are superconductors and what are they made of
Superconductors are materials that have zero resistance to electric current at low temperatures. They are generally made out of metals that are rare and hard to mine. Among conducting direct current electricity without energy loss, superconductors can also throw out magnetic fields which is the main reason they are extremely useful to create an artificial magnetosphere for Mars. Materials with superconducting properties include aluminum, magnesium diboride, iron pnictides, niobium, and many more. Technically, all of these materials listed are capable of generating magnetic fields and have zero resistance, but some are more conductive than others. For generating a field of this size and strength in a cold, dark, and empty environment, the best superconducting material would be niobium-titanium, because of the material’s ability to work perfectly well at the most frigid of temperatures.
3.2 Terraforming vs. partial terraforming
Terraforming is the process of making a planet, any planet whether it’s in or outside of our solar system, and making it resemble the Earth in some way. Not only this but on a fully terraformed planet, humans are able to walk around and breathe without a space suit or life support system of any kind. This means tackling three main components: temperature regulation, atmosphere design, and generating an artificial magnetic field.
Note: Above I used the term planet for my terraforming examples, but Moons with atmospheres are also able to be terraformed.
Partial terraforming (not to be confused with para-terraforming) is applying some, but not all of the aspects listed above under the definition of terraforming. This is what my current solution encompasses, specifically focusing on deflecting the solar wind. In the context of this proposal, partial terraforming means deflecting the solar wind to ensure astronauts are not exposed to solar UV radiation while maintaining an already established lunar habitat. This means that for this proposal to work, there must already be some sort of Moon habitat already set up where astronauts are growing planets and living inside a dome of some sort, to fully complete the partial terraforming process.
3.3 Purpose
Superconductors have many applications, one of which is assisting with terraforming and partial terraforming.
As mentioned previously, they are capable of generating powerful artificial magnetic fields to surround a celestial body, working even more efficiently in space than on Earth. These magnetic fields generated by our superconductors deflect the solar wind’s UV radiation drastically reducing the amount of space radiation that makes its way to the lunar surface.
Since the Moon does not have an atmosphere, there is not as much protection against these natural solar phenomena that can generate a lot of radiation which could potentially be very detrimental to an astronaut’s health. This is why applying superconductors in this way would shield astronauts from solar radiation and increase the amount of time humans can survive on the lunar surface exponentially.
4 — Artificial satellites
4.1 Artificial satellites vs. natural satellites
A natural satellite is an astronomical body that revolves around a planet, dwarf planet, or smaller body of the solar system. Natural satellites are often informally referred to as moons, like the name of the Earth’s natural satellite, the Moon. In our solar system, there are 690 reported natural satellites orbiting celestial bodies right now, just like our Moon does the Earth.
A satellite, often known as an artificial satellite, is a body that has been put into orbit in space on purpose by humans. Communication relay, weather forecasting, navigation, broadcasting, scientific research, and Earth observation are often what satellites are used for, however, artificial satellites aren’t limited to Earth and can orbit any planet or natural satellite with enough gravitational pull. It is estimated that there are currently over 3000 artificial man-made satellites orbiting the Earth right now.
4.2 Purpose
Superconducting rings
The superconducting rings will be positioned to orbit the Moon to be able to shield astronauts from solar UV radiation. Superconductors are ideal for an environment as cold as outer space, especially due to the lack of resistance. Granted, there is not a total lack of resistance as we have yet to achieve absolute zero, however, space is currently as close as we can get.
Satellites
The purpose of the artificial satellites launched is to monitor how much UV solar radiation the Moon is being exposed to. The solar wind is inconsistent and in order to improve this system in the future, it would be beneficial to have data on radiation levels day-to-day.
Note: This is a possible proposal for how we could theoretically go about making the lunar surface free of solar UV radiation, however, we currently do not have the materials or energy supply necesary to be able to implement this solution currrently. Though, if we adopt asteroid mining and other promising solutions to the material issue of things, then we may be able to implement a solution similar to this one on the timeline of a few centuries.
5 — Superconducting ring functions and technologies
5.1 Appearance, placement, and size of superconducting rings
The optimal shape for a superconducting ring is that of a torus, to maximize the strength of the magnetic field.
In place, we will have the torus-shaped superconductors orbiting all around the Moon. It should look something like this.
Now after we’ve touched on appearance and placement, let’s look at sizes.
Each superconducting ring will have a volume of 1 000 km³. This means that the magnetic field on either side of the torus will be about 500 km. The area of the Moon is about 38 million km², however, the area that we need to cover is half of that, 19 million km². This is because the dark side of the Moon receives no exposure to the solar wind. If each superconducting ring covers about 2 000 km (the torus itself = 1 000 km, magnetic field = 500 km on both sides) then we will need around 9 500 superconducting rings to be placed on the light side of the Moon to ensure full protection from the ultraviolet radiation of the solar wind.
5.2 Power supply for superconducting rings and materials used
Since an electric current is needed to generate an artificial magnetic field, there will be a flexible solar panel coating all the superconducting rings to power them.
Inside the rings, there will be a coil of supercooled liquid nitrogen maintaining a stable cooled temperature so that the superconductors can generate the magnetic field. The actual superconducting material that we have selected (niobium-titanium) will run through the ring. The entire ring itself will be made of aluminum to reduce costs.
The orbit of the superconducting rings will be synchronous with the orbit of the Moon. Since the Moon only ever shows the Sun the same face, we will only need to cover one-half of the Moon in superconducting rings.
5.3 Labeled diagram
6— Artificial satellite functions and technologies
6.1 Solar sensor payload
A payload can be defined as equipment (whether scientific or technological) carried by a satellite for a specific use.
This is not something required to build the satellite when thinking in first principles, but the payload is ultimately what determines the purpose of the satellite. In this case, our payload is a solar radiation sensor that can record and transmit data regarding solar UV radiation levels, which will then be used for research and potentially as an advanced warning system for major upcoming solar storms.
The solar sensor we will be using is NASA’s Total and Spectral Solar Irradiance Sensor — 2 (TSIS-2). The toolset of the TSIS-2 is a combination of the abilities of the Total Irradiance Monitor (TIM), as well as the spectral Irradiance Monitor (SIM). The TIM is capable of measuring the total brightness of the Sun, and the SIM can read solar spectral irradiance (SSI) through a range that makes up 96% of the energy in the entire solar spectrum.
However, since spectral irradiance is the amount of solar energy at the top of the Earth’s atmosphere (at the wavelength range, the SSI band), a version of the SIM must be tweaked to measure lunar spectral irradiance instead.
6.2 Antennas
As for our antennas, we will be using one high-gain antenna and two low-gain antennas.
High-gain antenna:
- The antenna will measure 3 meters and will deploy shortly after launch
- A similar model to the one NASA used for the MARS Reconnaissance Orbiter
Low-gain antenna:
- Two smaller low-gain antennas will also be placed on board in case of emergencies
- The Deep Space Network stationed on Earth can read the signal sent by the satellite even in the case that the antennas are not pointed at Earth
- Low-gain antennas shoot beams at broader wavelengths but less of the wavelengths reach Earth
6.3 Control system
A satellite control system (SCS) is one of the most essential subsystems on board a satellite. An SCS controls the:
- orbit of the satellite
- power the satellite receives
- radiation protection of the satellite
- attitude and pressure control for the satellite
It additionally powers communication with ground control.
For this mission, we will be using the Attitude and Orbit Control System, the SCS NASA used for their GRACE Follow-On mission.
6.4 Thermal control system and temperature-resistant materials
A thermal control system exists to maintain component temperatures within the ranges necessary for the given orbits, power demands, operations, etc. Right now, the temperature in outer space is about 2.7 Kelvin (around -270 degrees Celsius), and our satellite must be equipped to handle these extreme temperatures. Such is the purpose of our thermal control system. Now, our thermal control system will need to make sure that our satellite does not overheat or freeze.
To prevent overheating, heat is ejected from the satellite to space via radiators. To prevent the satellite from freezing, you choose materials that can withstand extreme cold without contracting and ruining your software and hardware.
The materials chosen to build a satellite, though not part of a thermal control system, still need to be able to withstand the most extreme of temperatures. This is why we will use aluminum alloy 6061 to build our satellite. Magnesium and silicon serve as the main components of alloy 6061, an aluminum alloy that has undergone precipitation hardening. It was created in 1935 and was first known as “Alloy 61S.” It has good weldability and mechanical qualities.
Aluminum alloy 6061 is one of the most commonly used materials that is used to build a satellite, and in this case, it is what we will be using to make sure temperatures do not drastically damage our satellites.
6.5 Telemetry control system
A satellite’s telemetry, tracking, and control (TT&C) subsystem acts as a link between the satellite itself and the infrastructure on the ground. The TT&C function’s goal is to make sure the satellite operates properly, monitoring the health of the spacecraft. The telemetry control system is one of the most vital parts of the satellite, especially for a mission to the Moon. The harsh environment of the Moon, which includes temperature extremes, radiation, and dust, can damage a satellite. To keep an eye on these conditions and modify the satellite’s operation as necessary, telemetry control systems are needed.
They enable data transmission between the satellite and the ground for spacecraft command and control. The control station on the ground and the satellite are connected by a telecommunications link to enable communication.
6.6 Labeled diagrams
A labeled diagram of the anatomy of the satellite and the network of superconductors.
Satellite sketch:
System sketch:
It is important to note that the satellite will be synchronous (they will orbit in sync with the Moon).
Note that the satellite will look different from the second picture and will probably resemble the first.
7 — Conclusion
How humans can deal with the problem of exposure to the solar wind’s ultraviolet radiation will undoubtedly be the determining factor in whether we become a multi-planetary species. It is a wicked problem that may take centuries to solve and one for which there is no shortcut. Artificial magnetic field generation is a necessary step when thinking about terraforming or partially terraforming another celestial body that protects our astronauts from several severe health problems. Without a way to deflect solar UV radiation, a moon or planet is never a permanent home for an astronaut no matter what countless safety precautions are taken.
