(Fig. 1: AI rendering of a Craterhab tourist settlement in Altiplano, Bolivia at 5000m altitude to mimic conditions of living on Mars)
What is Craterhab™ Technology?
Craterhab Technology is Mareekh Dynamics’ patented human habitation concept for Mars, Moon, or any other world or terrestrial environment with an atmospheric pressure significantly lower than the sea level pressure on Earth, ranging from low pressure to complete vacuum. It includes ultra-high tensile strength fabric domes called Craterhabs™ to withstand nearly 1 bar internal pressure relative to the exterior to achieve habitability, a patented Smart Design™, and an integrated on-demand radiation shield incorporated in the body of the dome to protect against high radiation environments.
Background
(Fig. 2: Artistic impression of a Craterhab base on Mars. Credit: M A Hussain)
The need to develop the Craterhab Technology arose in early 2020 with the Founder of SpaceX Elon Musk’s announcement of his vision to settle one million people on Mars towards the later half of this century (1). It seemed like a ridiculous idea in the beginning, especially since only a little over 600 people have ever been to the Earth’s orbit (2), with only 12 people having walked on the Moon (3), our nearest neighbour in the sky since the beginning of space age six decades ago.
Elon Musk’s vision is not entirely unfounded. It is deeply rooted in humanity’s ability to achieve the impossible when given a little push. Humans landed on the Moon mere six decades after the first powered flight. Neither do we lack the technology and expertise, nor the resources to achieve that. We just have to find the way.
Shortly following this announcement, Dr Robert Zubrin, the founder of The Mars Society, and one of the most vocal proponents of human settlement on Mars, met Elon Musk and announced an international competition to design a city for one million people on Mars, including all the logistical, engineering, and economic challenges that accompany it. We heeded the call.
Designing temporary habitats for a small group of individuals to last a few hours, days or even years is not too difficult. We have aced that, in Earth’s orbit in the form of space stations, big or small, or the lunar modules that landed on the Moon and became small temporary habitats for up to 3 days.
None of these are going to work if we want to establish a long term or permanent human settlement on Mars. The first reason is the sheer amount of resources that are needed for life support and basic essentials for the sustenance of life. Secondly, Mars is few tens to hundreds of times further away than Moon is to us, depending upon its orbital position relative to Earth. Getting there is time consuming and costly. So the number of people going to Mars for long-term or permanent settlement should meet a minimum threshold in number to include people from all the strata of basic expertise needed for exploration, engineering, housekeeping, healthcare, farming and other contingencies. This requires larger habitat systems to provide more room for activities and basic comfort of a long-term stay on an alien world. These pioneers will pave the way for thousands of people coming to settle on Mars from all walks of life and age groups. Settling such a sheer number of people requires enormous volumes of space with Earth-like, essentially micro-terraformed internal environments.
The single most important requirement for creating a micro-terraformed environment on Mars (or the Moon) is maintaining nearly one bar of internal habitat pressure against the near-vacuum on the outside. (Martian atmospheric pressure is 0.006 bar on average, and Lunar being 0 bar). Maintaining 1 bar of internal pressure means a huge amount of inflation stress on any habitat structure. This problem is compounded by the size of the habitat itself. 1 bar inflation pressure translates as 10 tons of outward force on any habitat structure per square meter.
Another problem with creating habitats for a permanent settlement for such a large number of people is the amount of material required. Even if much of the material could be manufactured locally in the settlement, this will divert a significant amount of the resources and human-power into manufacturing and construction, and will require a high level of maintenance. The large-scale habitat systems for long-term or permanent human settlements on Mars (or the Moon) should have the least possible material-to-volume ratio, and be simpler to construct and maintain.
This is where our Craterhab Technology comes in. We designed this habitat system for the International Mars City State Design Competition in 2020 to address the above mentioned key issues and made it to the list of top 10 finalists among hundreds of submissions from all over the world. It found a place in the book “MARS CITY STATES; New Societies for a New World” based on the top twenty submissions from the same competition. More recently, it has earned a well deserved mention by Dr Zubrin in his latest book, “NEW WORLD ON MARS; What We Can Create on the Red Planet”. Craterhab and its related technologies earned me a place as a finalist for the Australian space scientist of the year award for two years in a row, and Mareekh Dynamics three patents from the United States Patents and Trademark Office.
(Fig. 3: It all begins here. Excerpt from the book MARS CITY STATES; New Societies for a New World, composed of the selected submissions from the International Mars City State Design Competition in 2020)
(Fig. 4: Mention of our inflatable dome technology for human habitation on Mars in Dr Robert Zubrin’s THE NEW WORLD ON MARS; What We Can Create on the Red Planet)
(Fig. 5: Excerpt from our patent with the USPTO for the inflatable habitat concept based on our Craterhab™ Technology)
The Engineering Behind the Craterhab™ Technology
Let's delve into the engineering behind our patented technology.
As mentioned above, Craterhabs are large inflatable domes with nearly 1 bar internal pressure, primarily aimed to create an Earth-like internal environment on Mars or the Earth’s Moon with thin or no atmosphere, for permanent habitation of a large number of humans on these worlds. These are designed to be constructed over small (50-500 m or even larger) craters, turning them into micro-terraformed habitats, hence the name Craterhab™.
Why did we choose craters to build habitation domes? There is certainly a method in the madness.
The most important reason for choosing the Craters is the relative compactness of their rims as compared to the surrounding ground. The gravity of Mars is only 38% that of Earth. Lunar gravity is even lower at 16%. Gravities of Mars and Moon are not enough to create a compacted ground as we see on Earth. This is bad news for large inflated habitat systems such as Craterhabs, that need to be anchored into the ground. Relatively softer ground cannot provide enough grip to the foundations of an inflated dome containing near Earth-like pressure, trying to blow itself apart. The anchors will need to be much bulkier and deeper in case of the less compact Martian or Lunar regolith and bedrock layer. However, the rims of the craters on both worlds are more compact than the surroundings because they were born out of shock waves as a result of the meteorite impacts. This will offer a much superior interface for securing the peripheries of the inflating domes to the buried concrete anchors.
The other reason for choosing crater for building the inflated dome habitat is their perfect or near-perfect circular shape. This helps create a uniformly strong structure, reduces the engineering complexity, makes calculations easier, and increases the predictability of the stresses on the structure. A perfectly circular shape is also aesthetically pleasing.
Since many Crater habitats will be located in close proximity, and linked to each other through surface and underground tunnel system, the sloping walls of the crater under a Craterhab dome will provide a near-perpendicular interface facilitating construction and easing the access to the underground tunnels and infrastructure.
Craters also provide an extra volume of internal space as compared to building a large habitat structure on a flat surface, further reducing the material-to-volume ratio, and obviating the need for excavation, as nature has already done for us billions of years ago.
The Choice of Material
The primary stress-bearing material of a Craterhab is Dyneema™ for creating the hexagonal skeletal framework of the dome. Dyneema is one of the strongest synthetic fabrics manufactured at industrial level, with a tensile strength 15 times more than steel and is 7 times lighter (4). The skeletal frame of the dome is the main load or stress bearing component of the Craterhab. The other material is the Aramid (Kevlar or Twaron) - epoxy (resin) - carbon fiber composite, chosen for its translucency, which will form the main body of the dome. These hexagonal composite sections of the dome will have an additional layer of silicone-polyethylene composite on the outside and inside for additional thermal insulation and UV protection.
The Structure of a Craterhab
The Dome
(Fig. 6: Patent diagram of the Craterhab hexagonal skeletal frame structure)
(Fig. 7: Detailed diagram of the structure of the Craterhab skeletal frame from the patent)
(Fig. 8: Patent diagram of the cross section of the skeletal framework structure showing the arrangement of the Dyneema cables and the composite layers)
The main stress bearing component of a Craterhab is the hexagonal Dyneema (Spectra) skeletal frame. Each arm of a hexagon consists of a Dyneema cable going through a central Dyneema ring acting as a rigging ring or carabiner, to form a complete loop with two parallel sides. Each central ring will have three Dyneema loops at 120 degrees angle from each other, and attach to other Dyneema rings. The repeating pattern will form a hexagonal lattice skeletal structure which is the main stress bearing element of the dome. The diameter of the Dyneema cables and rings will be determined by the hoop stress of the dome as calculated by the size of the dome and the internal pressure (with an approximately 2.5x safety factor). This cable diameter can range from 5 cm for smaller domes to over 25 cm for very large domes as calculated for 0.4 - 0.6 bar internal pressure inside the dome, with a safety factor of 2.5x.
The optimal cable diameter of the Craterhab skeletal framework can be calculated based on the Hemi-ellipsoid geometry, Hoop Stress and the tensile strength of Dyneema (Td = 3500 MPa (N/m²).
Step 1: Calculating the surface area of the dome
(Fig. 9: Craterhab dome as a hemi-ellipsoid)
Step 2: Calculating Hoop Stress (σθ)
Calculating σθ for a dome thickness of 0.02m (2cm)
Step 3: Calculating the Dyneema thickness (D) required for the calculated amount of Hoop Stress
Step 4: Calculating the Volume of Dyneema (Vd) required
Step 5: Calculating the Diameter (D) of the Dyneema Skeletal Frame Cables
Diameter | Height | Pressure | 2.5x Safety factor | Lhex | D |
50 m | 20 m | 0.6 bar | 1.5 bar | 5 m | 58 mm |
100 m | 30 m | 0.6 bar | 1.5 bar | 10 m | 125 mm |
250 m | 50 m | 0.6 bar | 1.5 bar | 10 m | 215 mm |
500 m | 70 m | 0.4 bar | 1.0 bar | 10 m | 260 mm |
For a long term settlement on Mars, including habitation domes and greenhouses, natural sunlight and utilization of its daily cycle is essential for human physical and mental health, and for plant growth. Mars has a 24 hours 37 minute day which is very similar to that on Earth. So the entry of natural light inside the dome is important to make the best of it. However, on Earth, the thick atmosphere and the ozone layer stops nearly 90% of the harmful UV rays from reaching the surface. The thin Martian atmosphere does not stop the onslaught of UV rays on its surface. Transparent domes will not be able to stop much of the UV rays from entering the domes. So we needed something translucent to fill in the hexagonal skeletal frame, yet strong enough to augment the structural strength of the dome.
Our solution is the translucent Kevlar-epoxy (or resin) or Twaron-epoxy composites. These are superior strength materials with high tensile strength that can be crafted into translucent sheets filling the hexagonal lattice of the dome. In a Craterhab these composite layers will wrap around the opposing Dyneema cables in each hexagone in the skeletal framework, creating a double bi-layer of composite material. Each side of this bilayer will be further sealed with high-tensile translucent silicone-polyethylene composite layer; one on each side.
The purpose of the silicone-polyethylene layers is four-fold,
Thermal protection: Silicone offers superior thermal insulation due to its low thermal conductivity (5).
UV protection: Silicone has high absorption coefficient and reflectivity for light in Ultraviolet wavelengths (6).
Polyethylene can absorb some of the high energy particles (due to its high Hydrogen content) from cosmic rays augmenting the active radiation shield as discussed in subsequent units.
Sealing properties
To protect the outer lining of silicone-composite exposed directly to the thin and desiccating Martian atmosphere (or vacuum in case of the Moon), it can be covered on the outside with a thin layer of Polyimide or Kapton for excellent vacuum resistance.
The Foundation
(Fig. 10: AI rendering of construction of the concrete sandwich inside the crater rim using a remotely operated point-pivot construction crane with robotic arm)
(Fig. 11: Diagrammatic representation of the construction of crater rim trench and sandwich wall using a remotely operated robotic point-pivot construction crane)
Craterhab is an inflated structure to maintain an internal pressure of 1 bar (designed to stand a 2.5x safety factor, i.e. 2.5 bar). Though the actual pressure maintained on a Martian or Lunar Craterhab will be around 0.6 bar, similar to the El Alto metro area in Bolivia at 4000 m which is the largest city in Bolivia with nearly a million inhabitants, and a global happiness index of 6 (Ranked 74) (7). So maintaining 0.6 bar internal pressure may not pose any challenges for survivability or quality of life.
To keep things simple, we will assume a 1 bar internal pressure against essentially vacuum outside, which is a formidable inflation force exerted continuously on its containment. This equates to 10 tonnes of outward force per square meter. For a dome of 300 m diameter and height of 75 m, this equals nearly one million tons of outward inflation force. The structure is literally trying to blow itself apart at all times.
This requires some serious engineering to hold it down into the Martian or Lunar surface.
Unfortunately, due to the low gravity of both worlds (Mars and Moon), the ground is not as compact as that on Earth. But nature has given us a solution around this problem; the craters.
Craters are formed when a meteorite hits the surface of a planetary body, and disintegrates in a flash in a large explosion as it transfers its kinetic energy into the impacted surface. Much of this kinetic energy is released as a shock wave that pushes the material away from the point of impact against the unimpacted surface and also above it, creating an ejecta. The material that is ejected out circumferentially creates the crater rim, which is firmly pushed against the unimpacted surface, increasing the compactness of the formed rim of the crater.
Mars and Moon have a huge number of craters of all sizes, due to their thin or complete lack of atmosphere allowing meteorites of all sizes to crash on their surfaces. This includes craters between 50-500 m in diameter which is the target range of Craterhab construction, and numbered in millions.
The crater rims provide a perfect compact interface for securing the peripheries of the dome to the underground anchors. The near-perfect circular size of the crater also solves many construction problems. The entire dome along with its foundation can be constructed using a single robotic point-pivot crane with interchangeable arm modules, from carving out circumferential trench in the crater rim and laying of the anchors, to the spiral construction of the dome.
In order to lay the foundations in the crater rim, a circular trench is carved along the entire rim using a drill attached to the point-pivot crane. Cavities are then excavated deep inside the trench of pre-calculated size and number for underground anchors, with deep horizontal boreholes for secondary root anchors. These cavities are filled with a composite-reinforced concrete locally manufactured on Mars (or the Moon). This forms the subsurface anchor system with the secondary root anchors to enhance the underground fixation of the anchors against the sheer upward force. Then a composite-reinforced concrete sandwich wall is constructed with an outer and inner gap. Through these gaps, the Dyneema skeletal frame of the dome continues downwards into a tether system and attaches to the underground anchors. An intermediate torus anchor provides a soft cushioning to the tether system pushing up against the sandwich wall and evenly distributes the upward force.
The outer gap of the sandwich wall has a template section of the internal skeletal cable and tether system attached to the anchor and a deflated torus anchor for the construction of the future dome; a component of our Smart Design™ feature which is discussed later.
Internal Cables
(Fig. 12: Cross section of a Craterhab depicting the general layout of the internal Dyneema cable system)
(Fig. 13: Diagrammatic representation of the internal bi-radial Dyneema cable system)
Craterhabs are intended to be enormous structures. They can be anywhere from 50 m in diameter to up to 500 m or even larger, with heights approaching 80-100 m for larger domes. While aerodynamic in nature due to their hemi-ellipsoid shape and sloping profile in all directions, in the face of periodic dust storms on Mars, they can take on some serious wind loading. Even here, the fabric nature of the dome comes to rescue. Rigid glass domes rendered in many contemporary artwork for Mars habitats, cannot withstand the surface ripple effect created by winds on such large-scale structures. Though the Martian atmosphere is very thin, during global dust storms, which can last for months, the wind speeds exceeding 100 km/hr can become a formidable force to tackle.
To prevent the lateral movement of the dome, we devised an internal bi-radial cable system in our patented design. These Dyneema cables arise from two concentric circles on the ceiling of the dome from the central loop rings of the hexagonal skeletal frame. The cables from the inner circle fan outwards and attach to the underground concrete anchors towards the periphery of the crater floor, and the cables from the outer circle merge inwards and attach to a single large concrete post continuing underground as the core anchor of the dome. This configuration prevents the lateral movement of the dome in any direction in an event of high winds, and evenly distributes the inflation forces on the dome structure.
Smart Design™
(Fig. 14: Cross section of the sandwich wall with anchor system in the crater rim, showing the template for the future dome, a feature of Smart Design)
Smart Design™ is our patented contingency measure feature of the Craterhab Technology.
It revolves around the ease of maintenance and repair of the Craterhab domes.
Mars and Moon are extremely harsh worlds with little chance of survival should any of the life sustenance measures go wrong. Maintenance and repair will be of prime importance in ensuring survivability of humans on these worlds. While designing Craterhabs, we ensured contingency measures to be in place not only to prevent but also mitigate any adverse issues with the level of protection a Craterhab offers.
Ease of Maintenance
(Fig 15: The Smart Design; stepwise replacement on the aging Craterhab dome with the new dome without affecting the internal habitability)
An aging habitation infrastructure on Mars or Moon can be equivalent to a ticking time bomb, requiring very early repair, maintenance, or replacement. In developing Craterhab Technology, we have been mindful of this.
Cratehab is a smart design and allows replacing the aging dome with a new one without much disruption of the internal habitable environment. As mentioned earlier, the circular sandwich wall in the crater rim serving to connect the dome structure with the underground anchor system has two gaps between the three concrete walls. While the inner gap holds the continuation of the original dome tether system to the anchor, the outer gap contains a template for Dyneema skeletal frame of the second outer dome. When the original inner dome ages, the construction of the outer dome can commence from the pre-deployed template inside the outer gap. Once the outer dome is completed, the inner aging dome can be dismantled and removed, and the bi-radial cables attached to the new dome with minimum or no disruption of the routine interior life.
After a few years or decades, when the outer new dome starts aging, the inner dome can then be constructed from the template inside the inner gap, and once completed, the outer dome can be removed. This cycle can continue as many times as needed.
Ease of repair
One of the greatest threats to the integrity of Craterhabs are the micro-meteors, both on Mars and the Moon. While the odds of an astronaut on these worlds getting hit by a micro-meteors may be as low as being hit by lightning on Earth, for a giant structure like a Craterhab, the odds may be significant with serious consequences. Any puncture in craterhab anywhere on it is a bad one. Fortunately, most of the micro-meteors may be of submillimeter size and may puncture hole only a couple or so mm wide, this may still be enough to cause slow degassing of the internal atmosphere over a long period of time. Here, the multilayer structure of the craterhab body comes in for the rescue. A meteor strike, due to the fabric nature of the dome, may not result in a hole much larger than its own size, i.e. a few millimeters. The outgassing of the air from inside will result in the dome sinking a little bit over a long period of time due to a tiny and inconsequential loss of pressure which will result in the layers of the craterhab slide past each other by a few millimeters, sealing the dome. The internal pressure of the dome will seal the overlapping edges of the hole, stopping the air loss, until the definite repair of the dome is carried out.
In an extremely rare event of a larger meteor strike, such as a few centimeters, a larger hole will be formed, resulting in much faster but readily detectable air leakage. Still, it may take several hours before the internal pressure plunges to dangerous levels, but that will give enough time to fly a drone with a repair patch to simply stick to the hole from inside. The internal pressure will keep the repair patch in place and use of a simple glue will keep the patch from sliding out of place. A definite repair can then be done.
The Radiation Question
Some reference figures
Radiation on Mars 0.65 - 0.82 mSv per day (8)
GCR on Mars 0.67mSv per day (80- >95% of total radiation on Mars) (9)
Radiation on Earth 0.00082 - 0.0023mSv per day (from sea level to 2000m altitude) (10)
Radiation in space during transit to Mars 1.8mS per day (11)
Radiation in LEO/ISS: 0.4mSv per day
Radiation on Moon: 1.44mSv per day (12)
Radiation exposure on Mars is 300 - 1000 times more than it is on Earth. On the Moon, it is even higher, likely due to being close to the Sun and lack of any atmospheric protection, which is itself extremely thin on Mars. Earth’s vast magnetic field and a thick protective atmosphere offer sufficient protection for the sustenance of life.
Long term settlement on Mars or Moon will require creation of artificial protection against solar and cosmic radiation.
On Mars, nearly 80-95% of the space radiation is Galactic Cosmic Radiation (GCR)9. The rest is Solar Energy Particles (SEPs) and Ultraviolet (UV). GCR is the radiation that originated from deep cosmos as a result of supernovae or Gamma Ray Bursts or similar large scale events. Over 87% of this GCR consists of high energy protons, and the rest of it is He ions, with a small (<1%) fraction being heavier nuclei (13)(14). These are highly energetic particles that range from 0.1GeV to 10 GeV or higher in energies, though a large fraction of this radiation is in the range of around 0.1GeV. The SEPs consist of charged particles from the Sun that originate from Solar eruptions such as flares or Coronal Mass Ejections. These particles carry relatively less energy than GCRs (in the range of KeVs).
Radiation exposure on Mars is well above the accepted threshold of long term human survivability (or any other life). Measures need to be developed to reduce the exposure down to acceptable levels. The most direct way to mitigate this radiation is to create underground habitats. Other methods could be to develop surface habitats with 5 - 10 meters thick layers of regolith, water, or high hydrogen content synthetic materials such as Polyethylene.
The biggest problem with these methods is the difficulty in achieving large micro-terraformed environments for long-term living and comfort of a very large population on Mars. Developing underground settlements has several issues associated with it. The biggest challenge is to create a large underground excavated volume of space. Mars has several lava tubes and underground caves which can be voluminous but it comes with a hefty cost of infrastructure for reinforcement, and also the lack of natural sunlight and daily natural circadian rhythm. Due to lower gravity, Martian crust is not as compact as that on Earth, and it is not known how these underground cavities will behave when subject to Earth-like internal pressures. Mars is endowed with a 24hr 37 minutes day and a sun bright enough to create a comfortably bright day. Both these advantages will be lost with underground dwellings. Humans by nature are not underground dwellers. Underground habitats can cause claustrophobia and many mental health issues.
Creating surface habitats with thousands of tons of regolith or water shielding is challenging and unsafe from a structural point of view. It is practical for small habitats. For large micro-terraformed environments, this may need some extraordinary engineering. Also, access to natural sunlight will be an issue.
For any large-scale human habitation concept on Mars or the Moon, it should be far easier to construct on those worlds than it is on Earth. Both of the above measures are difficult to achieve for large scale construction on Earth. Imagine the challenges, technologies, and manpower required to achieve it on Mars or the Moon.
Craterhab Technology offers micro-terraformed surface habitat systems, which is a mix of large-scale surface and small-scale underground habitats, with predominant daily activities happening in the surface habitats. Craterhab fabric material, while offering over 90% protection against solar UV radiation due to its reflectivity and absorption of UV photons, offers almost no protection against Galactic Cosmic Radiation and Solar Energetic Particles. So a new kind of radiation shield had to be devised to protect the inhabitants of the Martian (or Lunar) habitats.
Meet AIRS
The Active Integrated Radiation Shield (AIRS)™
(Fig. 16: Patent diagram of the Active Integrated Radiation Shield, or AIRS)
AIRS™ is our patented on-demand powered radiation shield concept. The idea is to integrate a parallel circuit in the skeletal framework of the Craterhab dome carrying Direct Current, creating an artificial non-ionizing magnetic field to deflect the charged particles from the deep cosmos and the Sun, away from the main body of the Craterhab.
This requires a strong magnetic flux at such a small scale.
Earth’s magnetic field is weak, only in the range of micro Teslas (50 microTesla). But it is spread over a very large region around Earth and effective over large distances, tens of thousands of kilometers into space. The AIRS magnetic field is local, only a few tens to hundred or so meters. So it needs to be very strong. But that requires some impossible amount of power. My initial estimates of creating such a circuit using copper or iron cables required hundreds or MegaWatts, even GigaWatts to create a magnetic field even close to deflect the very high energy GCR particles coming at relativistic speeds. Superconductors come here to the rescue. A cold Martian environment helps in achieving that further. Cable made from rolled Yttrium Barium Copper Oxide (YBCO) superconductor may be made with copper as heat conductor, wrapped in a channel with a cryogenic liquid nitrogen flowing through or around it as a cooling medium. Liquid nitrogen as a coolant is a good choice for its very low dynamic viscosity at the critical temperature of YBCO (0.09 cP at -180C (93K) under ~ 5 bar pressure). For comparison, water’s dynamic viscosity is ~ 0.9 cP at room temperature. Low viscosity of liquid nitrogen is useful for pumping it under pressure through the superconducting cables several kilometers in total length as part of the shield.
What can be achieved with AIRS™?
GCR carries very high energy particles at relativistic speeds. The best practical solution still is to protect humans under several meters thick shielding of regolith or water, or going deep underground. It does not require any power. But for a long term habitation of a large number of humans, this will prohibit achieving large volume micro-habitats spanning hundreds of meters in diameter. The construction will be prohibitively expensive, and the structures unstable. Also access to natural light in the daily cycle will be limited. Crops will have to be grown in artificial light at the expense of power. We don’t build huge pyramids anymore, and for a good reason.
AIRS™ aims to achieve radiation protection against solar and cosmic radiation without needing to build a heavy physical shielding. The aim is not to stop or absorb the high energy charged particles completely but to deflect them just enough so that they are diverted away from the habitat. That's all. Also, we may only need to deflect enough fraction of the radiation to bring the combined daily or yearly dose to a safer minimum, enough to prevent any increase in the risk of cancer, radiation sickness or mutations in human body or in crops. We may want to achieve the same level of radiation exposure as inhabitants of high altitude environments. The radiation exposure to humans doubles every 1500m altitude15. So at an altitude of 4500m, the radiation may be 0.0065mSv per day (which is 8-10 times the radiation level at the sea). This is still a long way to reduce radiation on Mars (or Moon) which is hundreds of times that on Earth at sea level. Astronauts at the ISS are exposed to a radiation 60 times this number. But is that compatible for long term survival?
The maximum permissible dose for medical professionals is around 0.14mSv daily to prevent any long term health effects16. This is little over 20 times the radiation at 4500m, and nearly 3 times less than that on the ISS, and nearly 5 times that on Mars. This is the radiation exposure we may settle for as the maximum permissible radiation dose per day for humans on Mars, or on the Moon.
So we need to divert nearly 80% of the total radiation on Mars (or correspondingly on the Moon which will still be over 90%). This is nearly 75% of the GCR. For the sake of calculations, we may consider diverting 100% of the GCR on Mars, which will factor in occasional outdoor excursions outside the safety of a Craterhab.
So, how much power will be needed to divert high energy charged protons of the GCR carrying 0.1GeV, 1GeV, and 1GeV energies for 50m to 500m diameter Craterhab using AIRS™ consisting of YBCO superconducting cables running parallel in the Craterhab skeletal frame?
Step 1: Magnetic field strength required to deflect 0.1GeV and 1GeV protons
Lorentz force required to deflect the protons
F = qvB
Where:
q is the charge of the proton (1.6×10 e−19 C)
v is the velocity of the proton
B is the magnetic field strength
Step 2: Calculate the velocity of the proton
Where:
m is the mass of the proton (1.67×10−27kg)
E is the energy of the proton in Electron Volts
Step 3: Calculate the Radius of curvature (r) of the proton’s path in the magnetic field
r = mv/qB
Where m is the mass of the proton (1.67×10e−27 kg)
Radius of curvature of a proton can be assumed equal to the radius of the dome.
Step 4: Calculate the magnetic field strength (B) required to keep the proton on a circular path with radius equal to half the diameter of the Craterhab
B = mv/qr
Step 5: Calculate the current through each YBCO Cable
To produce the required magnetic field, we need to calculate the current I through each of the parallel cables. Assuming they are evenly placed parallel to each other in the skeletal frame of the Craterhab.The magnetic field produced by a long straight current-carrying conductor at a distance r is given by:
B = μ0I/2πr
Where:
μ0 is the permeability of free space (4π×10e−7 Tm/A)
I is the current through the conductor
r is the distance from the conductor
Step 6: Calculate the Power Required
Since we are using a superconductor, theoretically, the current can flow perpetually in the circuit producing a magnetic field. However, power will be required continuously to maintain cooling of the superconducting cable below its critical temperature which depends upon the efficiency of the cooling system and the heat load. Resistive power losses will be negligible. For superconductors like YBCO, the electrical power consumption due to resistance is negligible because they have zero or near-zero electrical resistance.
Lets calculate power required to run direct current in a YBCO superconducting cable (tightly coiled YBCO tape) 200m in length, maintained at -181C. The cryogenic liquid used is Liquid Nitrogen. The outside ambient temperature is -50c, however, the liquid nitrogen is circulated through the Martian permafrost deep underground at -70c in copper tubes before circulating it through the refrigeration system and then through the cable system, in a closed loop. The liquid nitrogen is pumped through a 1cm wide channel around the YBCO cable system.
To calculate the power required to run the superconducting system on Mars, we'll follow these steps:
1. Determine the Heat Load
Calculate the heat load on the system due to conduction and other sources.
Consider the heat exchange between the liquid nitrogen and the Martian permafrost.
The heat load Q is the amount of thermal energy that needs to be removed to maintain the system at -181°C.
For a cable with insulation, the conductive heat load can be calculated using Fourier's Law:
Qcond = k⋅A⋅ΔT / d
Where:
k is the thermal conductivity of the insulation material (W/m·K).
A is the surface area through which heat is conducted (m²).
ΔT is the temperature difference between the ambient temperature and the superconducting temperature (K).
d is the thickness of the insulation (m).
Assume some typical values:
Ambient temperature on Mars (Tambient) = -50°C (223K)
Temperature of liquid nitrogen in the permafrost (TLN2T) = -70°C (203K)
Superconducting temperature (Tsuperconducting = -181°C (92K)
Thermal conductivity of insulation (k) = 0.02 W/m·K (for high-quality insulation)
Thickness of insulation (d) = 0.01 m
Length of the cable (L) = 200 m
Diameter of the cable (D) = 0.01 m (assuming it’s tightly coiled YBCO tape) 2. Calculate the cooling power required using the cooling efficiency:
Assuming the Coefficient of Performance (COP) of the cooling system is 0.2 (typical for cryogenic systems).
The actual power required for the cooling system (Pcooling ) is:
Pcooling = Qcond / COP
Below are the calculated power requirements to deflect up to 0.1 - 1 GeV particles from solar and cosmic radiation on Mars using AIRS™, using YBCO superconductor (coiled into cable) grid and liquid nitrogen as cryogenic fluid, factoring in the diameter of the dome, magnetic field required, the current, heat load and the cooling power needed. These figures are based on our preliminary calculations, and may further include the power to pump the liquid nitrogen at -181c under 5 bar pressure, and also using the permafrost at -70C which can help in reducing the cooling load.
Diameter | Hex sides | Grid Length | GCR energy | Magnetic field strength | Current | Power input |
50m | 5m | 200m | 0.1GeV | 57mT | 1200kA | |
1GeV | 182.4mT | 3806kA | 7kW | |||
100m | 10m | 800m | 0.1GeV | 28.7mT | 1200kA | |
1GeV | 91.2mT | 3806kA | 28kW | |||
250m | 10m | 3330m | 0.1GeV | 14.4mT | 643kA | |
1GeV | 45.6mT | 2040kA | 116kW | |||
500m | 10m | 19350m | 0.1GeV | 5.75mT | 248kA | |
1GeV | 18.24mT | 786kA | 675kW | |||
The power consumption to run AIRS even for the larger Craterhabs in the range of 500 m is not impractical. Though physical barriers against the radiation such as several meters thick regolith or water shielding does not require power, they do require heavy infrastructure to hold, and prohibit construction of large volume habitats, or allow natural light. AIRS is scalable and offers safety for the surface habitats while allowing natural light for normal human circadian rhythm, plant growth, and most other advantages natural light and its cycle has to offer.
(Fig. 17: Artistic rendering of AIRS in action, deflecting and concentrating the charged particles in the Solar and Cosmic radiation. The aurorae formation shown here is only for the artistic depiction, which may not form in reality, due to very low density of the Martian atmosphere)
Power Generation on the Moon and Mars
Moon
(Fig. 18: AI rendering of a Craterhab on the Lunar surface with a solar power array)
Power generation on the Moon will go in line with the amount of infrastructure including mining, construction, exploration and the number of residents on the Moon and requirement for their life-support and maintenance of habitat environments. Per capita energy requirement or consumption will be many times more than that on Earth. The Moon due to its low gravity (16% that on Earth), lack of resources, and its proximity to the Earth, is less likely to become a hub for a permanent human settlement. However, a permanent presence of a small number of humans (few hundred to thousands) like that on Antarctica is more plausible for exploration, limited manufacture, mining, research, and tourism.
The main source of power on the Moon is going to be solar. There are several reasons for this. The biggest is the similar direct solar flux on the Moon as that on Earth i.e. around 1400W/m2. However, solar flux on the Moon does not suffer from atmospheric dampening. Maintenance of solar panels will also be easier as no dust blows on the Moon, and there are no atmospheric reactants to damage the panels in the long run. A kilometer array of solar panels on the Moon may produce up to 1400 MW of power, which may be sufficient for the requirements of a medium to large size base.
The Moon has long days, equivalent to nearly 15 Earth days. This leads to a long cold night of the same length with no solar flux. Huge batteries will be required to store the daylight energy to keep the base running during the cold and dark Lunar night. Much of the construction, manufacturing and mining may need to be halted at night as there may just be enough battery backup for maintaining habitation life support only during the long Lunar night.
During Lunar nights, nuclear option (Radioisotope Thermonuclear Generator or RTGs) may also be feasible as a primary power supply source with stored battery backup as the secondary. A single RTG can produce up to a few hundred watts with a price tag of tens of millions of dollars. To match the power output of solar panels, hundreds of RTGs may be needed to generate a few tens of kilowatts. However, they do not require sunlight for working, and will work round the clock.
Mars
(Fig. 19: An artistic depiction of a Craterhab base on Mars with solar arrays in the vicinity)
The initial power source for a Martian colony will be solar, with limited nuclear power backup in case of lack of sunlight amid global dust storms on Mars that can last for weeks or months at a time.
Later, large-scale nuclear fission reactors will become a mainstay of power generation on Mars to meet the growing needs of a budding permanent settlement on the red planet.
Mars will have a very “power-hungry” economy, with very high per capita usage of energy. The main expenditure of power will be in ore processing, maintaining habitability of living spaces, fuel production for ascent vehicles, rovers, mining operations, construction, manufacture of machinery, and terraforming. Personal power usage will be very similar to a modern industrial nation on Earth but combined power consumption per capita can be compared to that of Iceland17, where over 80% of the power is consumed by the industrial sector, especially mining and processing of Aluminum. In a Martian context, this figure may be over 90%, with only 1 – 2 % used for domestic consumption inside the habitats and living spaces.
In fact, it will be a good comparison with Iceland to extrapolate the power consumption by a sizable Martian settlement. Per capita energy consumption of Iceland is roughly 5800 watts per person; over 80% of which is used by industry, and 15% (870 watts) is domestic consumption. Keeping this figure the same, except that this would be only 2% of the per capita usage of power, the total per capita power requirement can be extrapolated to nearly 44,000 watts per person. For a million strong population on Mars, this gives the average power requirement of a whopping 44 billion watts (44000 megawatts) at any given time.
The area required for solar panels for production of this much amount of electricity on a fine sunny day with minimal dust or haze in atmosphere will be equivalent to at least 325 square kilometres, provided 20% efficiency of solar cells. In order to provide relatively reliable power throughout the daylight hours, it may need to be three times larger, roughly 1000 – 1200 square kilometres. The main issue will be the cost of construction of such a huge power array and the unreliability of it during months long Martian dust storms. Couple of methods can be utilized to ensure seamless supply of power from such solar arrays including storing energy by charging huge battery arrays similar to Tesla Battery in Jamestown Australia, and production of liquid hydrogen fuel cells from subsurface water ice or permafrost to run generators during dust storms to ensure continuous supply of electricity to meet the minimum needs. These panels will age with time and will incur huge cost and human hours for maintenance and replacement. Though promising, solar power generation wouldn’t be a long-term solution to meet energy needs of a large permanent settlement on Mars.
This leaves us with nuclear power as the only practical long-term option for its relatively cheaper infrastructure and reliability of power output. Until a safe and practical way of producing fusion power is discovered, fission reactors will be the mainstay of power generation.
Two kinds of nuclear-powered reactors can be considered:
1. Radio-isotope Thermoelectric Generators (RTG)
These relatively low cost and long-lasting power sources would be useful early in the establishment of Martian settlements, but due to their low output and efficiency (in kilowatts only, and 3-7% efficiency), these must soon be replaced with larger and more efficient designs like boiling water reactors.
2. Small Modular Reactors (SMR)
More efficient and powerful, these reactors would utilize water extracted from permafrost. Each compact unit will be capable of generating up to 100 to 300 megawatts of power. These reactors will be dependent upon procurement of nuclear fuel from Earth, which may increase the cost of power production several fold as compared to that on Earth. Dr Robert Zubrin has explained a practical solution on procurement of nuclear fuel from Earth to be used in fission reactors on Mars in his book, The New World on Mars (2024).
The Mareekh Process™
Mareekh Process is a novel patented hybrid power generation concept for Mars by Mareekh Dynamics, involving In-Situ Resource Utilization (ISRU) of Martian subsurface ice (glaciers or permafrost). This process involves extraction of water through subsurface heating up of Martian ice using solar or limited-nuclear auxiliary power sources to create a mixture of supercritical water and saturated flash steam, and releasing it into surface steam turbines operating at near-vacuum atmospheric pressure on Mars. Mareekh Process is a hybrid of back-pressure, and condensing-type steam turbines, except there is no surface condenser involved, and instead utilizing the cold Martian atmosphere of extremely low pressure to achieve adiabatic expansion and condensation of end-steam while releasing a small fraction of it into the atmosphere. Mareekh Process utilizes the entropy imbalance between subsurface water (ice) and the atmosphere created billions of years ago. Mareekh Process rapidly achieves very high entropy of the end-steam and can extract several megawatts of net power per kilogram conversion of subsurface ice into steam, essentially converting the entropy imbalance of subsurface ice and the atmosphere as a source of energy. The details of the working of the Mareekh process and its thermodynamic principles and calculations are beyond the scope of this article, and are discussed separately in our previous blog articles (18) (19).
(Fig. 20: In-Situ Resource Utilization of subsurface ice on Mars for power generation through our novel patented Mareekh Process for a nearby Craterhab city)
Terrestrial Applications of the Craterhab™ Technology
(Fig. 21: Frequently visited or permanently inhabited high altitude environments on Earth. Craterhab Technology may help create small to large pressurized habitation domes for mitigate Acute and Chronic Mountain Sickness)
(Fig. 22: AI rendering of a small pressurized dome built on Craterhab Technology at Mt Everest base camp to treat Acute Mountain Sickness in climbers)
(Fig. 23: AI rendering of a Craterhab base in Altiplano, Bolivia)
(Fig. 24: Artistic impression of the interior of a Craterhab, with buildings and amenities)
As discussed earlier, Craterhabs are ultra-high tensile strength fabric domes that can maintain at least 1 bar of internal pressure, turning small Martian and Lunar craters into micro-terraformed Earth-like environments. The domes use a hexagonal skeletal framework of Dyneema cables and silicone-polyethylene and aramid(Kevlar)-epoxy-carbon-fiber composite patches, anchored securely into the crater rims. This technology is aimed at creating pressurized habitats for human settlement on Mars, enabling a near Earth-like living environment.
On Earth, Craterhab™ Technology has significant applications in High-Altitude Low-Pressure (HALP) environments, such as high-altitude regions of the world including Tibet in Asia, and Altiplano in South America, where low atmospheric pressure poses a multitude of health challenges. Current measures to address altitude sickness and Chronic Mountain Sickness (CMS) are limited and not suitable for long-term habitation.
The pressurized habitation domes built on the same principles as the Craterhab Technology for Mars and the Moon, can provide sea-level pressure to help treat the Acute Mountain Sickness (AMS), High Altitude Cerebral Edema (HACE), High Altitude Pulmonary Edema (HAPE) and Chronic Mountain Sickness (CMS). Large pressurized domes maintaining sea-level pressures with amenities such as residential buildings, hotels, hospitals, schools and shopping areas may help prevent development of Acute and Chronic Mountain Sicknesses in visitors and permanent residents of high altitude environments. This will keep the tourists and visitors safe during adventure tourism of high altitude regions, and improve health, productivity, and lifespan for residents in these regions. This technology can also be applied to mountain climbers offering safer and more comfortable base camps in extreme altitudes.
The Halfway-to-Mars (H2M) vision by Mareekh Dynamics leverages Craterhab™ Technology to create mock Mars bases in ultra-HALP environments on Earth. These bases, located in regions nearing 5000 m or above, will simulate living conditions on Mars with a 0.5 bar pressure difference between the interior and exterior. This will not only aid in engineering and testing of the Craterhab domes but also promote astro-tourism and astronaut training, preparing humanity for future Mars colonization. By living in these simulated Martian environments, astro-tourists and astronauts can experience the challenges of living on the red planet, and help develop and refine necessary protocols and technologies.
Main advantages of the Craterhab™ Technology
The main advantages of Craterhab Technology over contemporary designs are:
1. A disruptive convergent technology
Craterhab Technology represents a revolutionary approach to human habitation on Mars by integrating large, pressurized dome structures with individual habitation pods or structures contained within it. Unlike traditional surface pods that are reinforced, sealed, and equipped with separate airlock and life support systems—making them costly to construct and maintain—Craterhab Technology allows for the creation of smaller habitation structures within the safety of a large pressurized and radiation-free dome. Since these internal pods will be inside the much larger micro-terrafromed environments of the Craterhab domes, they can be made from lightweight materials like plastic or fiberglass, significantly reducing the manufacturing costs and obviating the use of complicated technologies.
Furthermore, Craterhab Technology will foster a sense of community, as inhabitants can move freely between pods without wearing space suits, creating an environment similar to that of communities on Earth. This technology will not only simplify and economize the construction of individual habitats but also enhances the overall living experience on Mars or the Moon.
2. Structural Efficiency
The hexagonal lattice structure of Craterhab domes allows for a larger volume to be enclosed with relatively less material. This is because the dome shape is inherently strong and distributes stress evenly, allowing for thinner and lighter materials to be used without sacrificing strength.
3. Small material-to-volume ratio
Large domes have a lower surface area to volume ratio compared to pods. This means that for the same internal volume, a dome requires less material to cover the surface area. This is advantageous for reducing the overall material needed for construction. Moreover, the depth of craters will provide extra volume of space for the same amount of material needed for building such domes on level surfaces, further reducing the material-to-volume ratio without the need to do artificial excavation as nature has already done that ‘for us’ billions of years ago.
4. Large micro-terraformed habitats
Craterhab Technology allows creation of huge internally terraformed (‘micro-terraformed’) habitats mimicking Earth-like environments as closely as practically possible in the existing technology on an alien world.
5. Surface dwelling
Humans are surface dwellers. We cannot settle permanently in underground habitats without adverse physical or mental impacts. We also need natural light and physical perception of the day-night cycle. Craterhab Technology harnesses these advantages of a near 24 hr day-light cycle on Mars and the natural light from the Sun.
6. Smart use of the Martian and Lunar geology
Martian and Lunar surfaces are full of craters. Craterhab Technology is developed with human settlement on Mars in mind, by using the near-perfect circular shaped craters with compact rims to act as a secure interface for anchoring the Craterhab domes into an otherwise softer ground on Mars (and the Moon) as compared to the Earth. The round shape of craters will provide ease of developing a single set of scalable engineering parameters for all sizes. The same construction principles can be applied on the Moon for the establishment of a human settlement.
7. Integrated radiation shield
Craterhab Technology allows establishment of a powered and scalable on-demand radiation shield integrated into the body of the Craterhab dome structure (Active Integrated Radiation Shield or AIRS™) enabling surface dwelling and access to natural light and day-night rhythm.
8. Terrestrial application in healthcare, adventure and astro-tourism in high altitude regions
Craterhab Technology can address the challenges of living in extreme environments on both Earth and Mars. By providing pressurized habitats with near sea-level pressure, this technology aims to improve health and productivity in high-altitude regions and prepare for future Mars colonization.
Gallery
Here is a collection of author made and AI rendered images of our Craterhab Technology. The AI generated images are close, but not accurately depictive of our technology, including showing smaller size domes, absence of internal bi-radial cables, and larger hexagonal pattern. Author generated images are more in line with the intended technology)
(Artistic impression of a Craterhab base on Mars. Credit: M A Hussain)
(Cross section of a Craterhab with structures, and access to underground tunnels and infrastructure)
(A Craterhab base on Mars)
(A Craterhab base on the Moon)
(A Craterhab base on the Moon)
(A Craterhab tourist settlement in Altiplano, Bolivia)
(A Craterhab tourist settlement in Tibet, China)
(Interior of a Martian Craterhab depicting a micro-terraformed environment)
(Interior of a Martian Craterhab with 3D printed residential complexes)
(Interior of a Lunar Craterhab inside a small crater on the Moon. Humans can live in simple structures such as polymer or fabric tents inside the safety of the micro-terraformed environment of a Craterhab)
(Interior view of another small Lunar Craterhab)
(Interior of a manufacturing Craterhab on Mars. Such manufacturing facilities inside a comfortable shirt-sleeve environment will be the key for further expansion of the human settlement on Mars. Much of the material and components for construction will be made inside these Craterhabs)
Acknowledgement
I am immensely thankful to our founding team of Mareekh Dynamics, Mehdi Hussain and Waqar Haider for their help and contribution in developing Craterhab™ Technology and its related components. I am also thankful to Ayaz Hussain, Rida Fatima and Padraic Koen for their support for further development, and their valuable feedback.
References
Elon Musk’s plan to send 1 million people to Mars: www.businessinsider.com/elon-musk-plans-1-million-people-to-mars-by-2050-2020-1
Space Demography www.worldspaceflight.com/bios/stats.php
Number of Humans to the Moon, www.astronomy.com/space-exploration/how-many-people-have-gone-to-space/
Dyneema strength usarope.net/why-choose-dyneema-rope-vs-steel-wire-rope-for-heavy-duty-rigging/
Thermal conductivity of Silicone www.intertronics.co.uk/wp-content/uploads/2016/11/TB2007-12-Thermally-Conductive-Silicones.pdf
Optical properties of Silicone www.pveducation.org/pvcdrom/materials/optical-properties-of-silicon
World Happiness Index worldhappiness.report/ed/2024/happiness-of-the-younger-the-older-and-those-in-between/#ranking-of-happiness-2021-2023
Radiation on Mars marspedia.org/Radiation#:~:text=It%20provides%20moderate%20protection%20against,times%20the%20average%20on%20Earth.
Galactic Cosmic Radiation on Mars phys.org/news/2013-12-scientists-publish-surface-mars.html
Radiation on Earth www.cnsc-ccsn.gc.ca/eng/resources/fact-sheets/natural-background-radiation/
Radiation in Space www.youtube.com/watch?v=_GeapdGbGEc&t=401s
Radiation on Moon www.space.com/moon-radiation-dose-for-astronauts-measured
Galactic Cosmic Radiation agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2023SW003470
Radiation Environment on Marsui.adsabs.harvard.edu/abs/2021cosp...43E1874Z/abstract#:~:text=Astronauts%20may%20encounter%20two%20types,difficult%20to%20shield%20against%20GCRs.
Radioactivity and Altitude isnap.nd.edu/assets/213123/radioactivity_lecture_13.pdf
Maximum Permissible Radiation Dose www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/maximum-permissible-dose
Power Consumption in Iceland orkustofnun.is/en/information/numerical_data/electricity
Understanding the Mareekh Process www.mareekh.com/post/understanding-mareekh-process-a-thermodynamic-journey
Presentation on Mareekh Process, Arizona State University
www.mareekh.com/post/presentations-at-the-2023-int-mars-society-convention- oct- 5-8-2023-arizona-state-university
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