Category: Moon

It won’t just be astronauts returning to the Moon in the next decade. They’re also going to be bringing their equipment, including shelters and vehicles. And NASA’s working on the ultimate off-road vehicle. It’s a six-wheel drive lunar truck reminiscent of the Mars rovers, but designed to carry astronauts and their equipment.

Oh, and you can have any colour you like, as long as it’s gold.

When designing a new vehicle for human planetary exploration, the NASA engineers threw out all their old assumptions and started from a clean slate.

“To be honest with you, it was scary when we started,” said Lucien Junkin, a Johnson robotics engineer and the design lead for the prototype rover. “They tasked us last October to build the next generation rover and challenge the conventional wisdom. The idea is that, in the future, NASA can put this side-by-side with alternate designs and start to pick their features.”

Right away, they challenged the concept that a vehicle should have 4 wheels. The Mars rovers, still going after all these years have demonstrated that 6 wheels, capable of independent steering, work well in a rough environment. And if one wheel goes, you can still get by just fine with the other 5.

With the ability to travel in any direction, the lunar truck will let the astronauts drive down into very steep craters. It can crawl down sideways, maintaining the lowest centre of gravity. It can turn around in any direction to maneuver around rocks and smaller craters.

On the Apollo rover, the astronauts couldn’t go in reverse because they couldn’t see where they were going. They couldn’t turn around or look over their shoulders like you would in a car. But with the lunar truck, the astronaut can turn completely around on the vehicle – backwards is the new forwards.

The purpose of the lunar truck is to serve as a technology demonstration. Some, all, or none of its developments will actually find their way to the final lunar surface. But until then, some engineers are going to have off-road fun, working on the unique challenges of driving on the Moon.

If you’d like to see some videos of the rover in action, check out this site.

Original Source: NASA News Release

Building the first Moon base will be the biggest challenge mankind has ever embarked on. We can already speculate about the hazards, natural and manmade, associated with a human presence on the lunar surface. In response, we already have some habitat structures in mind – ranging from inflatable structures to underground burrows inside ancient lava vents. Now it is about time we seriously start designing our first habitat structure, protecting us from micrometeorites, sustaining terrestrial pressures and using locally mined materials where we can…

In Part 1 of this “Building a Moon Base” series, we looked at some of the more obvious hazards associated with building a base on another planet. In Part 2, we explored some of the current design concepts for the first manned habitat on the Moon. The designs ranged from inflatable structures, habitats that could be constructed in Earth orbit and floated to the lunar surface, to bases hollowed out of ancient lava tubes under the surface. All concepts have their advantages, but the primary function must be to maintain air pressure and reduce the risk of catastrophic damage should the worst happen. This third installment of the series deals with the basic design of a possible lunar base which optimizes space, makes maximum use of locally mined materials and provides protection from the constant threat of micrometeorites…

“Building a Moon Base” is based on research by Haym Benaroya and Leonhard Bernold (“Engineering of lunar bases“)

The key factors influencing structural designs of habitats on the Moon are:

• One-sixth terrestrial gravity.
• High internal air pressure (to maintain human-breathable atmosphere).
• Radiation shielding (from the Sun and other cosmic rays).
• Micrometeorite shielding.
• Hard vacuum effects on building materials (i.e. out gassing).
• Lunar dust contamination.
• Severe temperature gradients.

In addition to addressing these issues, the lunar structures must be easy to maintain, inexpensive, easy to construct and compatible with other lunar habitats/modules/vehicles. To achieve inexpensive construction, as much local material must be used as possible. The raw material for inexpensive construction could be the plentiful quantities of regolith readily accessible on the lunar surface.

As it turns out, lunar regolith has many useful properties for construction on the Moon. To complement lunar concrete (as introduced earlier in Part 2), basic building structures may be formed from cast regolith. Cast regolith would be very similar to terrestrial cast basalt. Created by melting regolith in a mold and allowing it to cool slowly would allow a crystalline structure to form, resulting in highly compressive and moderately tensile building components. The high vacuum on the Moon would greatly improve the manufacturing process of the material. We also have experience here on Earth in how to create cast basalt, so this isn’t a new and untested method. Basic habitat shapes could be manufactured with little preparation of the raw materials. Elements like beams, columns, slabs, shells, arch segments, blocks and cylinders could be fabricated, each element having ten times the compressive and tensile strength of concrete.

There are many advantages to using cast regolith. Primarily, it is very tough and resistant to erosion by lunar dust. It could be the ideal material to pave lunar rocket launch sites and construct debris shields surrounding landing pads. It could also make ideal shielding against micrometeorites and radiation.

OK, now we have basic building supplies, from local material, requiring minimum preparation. It is not too hard to imagine that the process of fabrication cast regolith could be automated. Prior to a human even setting foot on the Moon, a basic, pressurized habitat shell could be created, waiting for occupation.

But how big should the habitat be? This is a very tough question to answer, but the upshot is that if any lunar habitat will be occupied for long periods, it will have to be comfortable. In fact, there are NASA guidelines stating that, for missions of longer than four months, the minimum volume required by each individual should be at least 20m³ (from NASA Man Systems Integration
Standards, NASA STD3000, in case you were wondering). Compare the needs of long-term habitation on the Moon with the short-term Gemini missions in the mid-1960’s (pictured). The habitable volume per crewmember in Gemini was a cosy 0.57m³… fortunately these early forays into space were short. Despite NASA regulations, the recommended volume per crewmember is 120m³, approximately the same as the living space on the International Space Station. A similar space will be required inside future habitats on the Moon for crew wellbeing and mission success.

From these guidelines, habitat designers can work on how best to create this living volume. Obviously, floor space, habitat height and functionality will need to be optimized, plus space for equipment, life support and storage will need to be factored in. In a basic habitat design by F. Ruess, J. Schänzlin and H. Benaroya from a publication entitled “Structural design of a lunar habitat” (Journal of Aerospace Engineering, 2006), a semi-circular, “hangar” shape is considered (pictured).

The shape of a load-bearing arch is a close ally for structural engineers, and arches are expected to be a major component for habitat design as structural stresses can be evenly distributed. Of course, architectural decisions such as the stability of the underlying material and slope angle would have to be made whilst building the habitat foundations, but this design is expected to address many of the issues associated with lunar construction.

The biggest stress on the “hangar” design will come from internal pressure acting outward, and not from gravity acting downward. As the habitat interior will need to be held at terrestrial pressures, the pressure gradient from interior to the vacuum of the exterior would exert a massive strain on the construction. This is where the arch of the hangar becomes essential, there are no corners, and therefore no weak spots can degrade integrity.

Many more factors are considered, involving some complex stress and strain calculations, but the above description gives a taste as to what structural engineers must consider. By constructing a rigid habitat from cast regolith, the building blocks for a stable construction can be built. For added protection from solar radiation and micrometeorites, these arched habitats could be built side-by-side, interconnecting. Once a series of chambers have been built, loose regolith could be laid on top. The thickness of the cast regolith will also be optimized so the density of the fabricated material can provide extra protection. Perhaps large slabs of cast regolith could be layered on top.

Once the basic habitat modules are constructed, the layout of the settlement can begin. Lunar “city planning” will be another complex task and many module configurations must be considered. Five main module configurations are highlighted: Linear, Courtyard, Radial, Branching and Cluster.

The infrastructure of the future lunar settlement depends on many factors, however, and will be continued in the next instalment.

• Building a Moon Base: Part 1 – Challenges and Hazards
• Building a Moon Base: Part 2 – Habitat Concepts
• Building a Moon Base: Part 3 – Structural Design
• Building a Moon Base: Part 4 – Infrastructure and Transportation

“Building a Base Moon” is based on research by Haym Benaroya and Leonhard Bernold (“Engineering of lunar bases“)

Article based on published work by Haym Benaroya and Leonhard Bernold: “Engineering of lunar bases”

Plans are afoot to build a manned base on the Moon. As you probably would have guessed, there are quite a few hazards and dangers with sending humankind back to establish lunar “real estate”. However, once our intrepid lunar colonists begin to build, the hazards will become less and development will accelerate. This is all very well, but how will we gain that first foothold in the lunar regolith? What will be the best form of habitat structure that can be built to best suit our needs? These questions have some obvious and not-so-obvious answers from the structural engineers already publishing their ideas and building prototypes…

In Part 1 of this mini series on “Building a Moon Base”, some of the dangers facing astronauts and future colonists were outlined. Moon dust could (in all probability) be a health risk, micrometeorites and other speeding projectiles could burst pressurized structures, highly energetic particles from the Sun could irradiate unprotected settlements, damage to machinery could be caused by the vacuum… generally a mixed bag of bad news. But if anything else, we humans have the ability to beat the odds and succeed (if politics and finances allow of course!). This second installment deals with the habitat structural concepts that are being planned to best serve the first, interim and permanent settlements on the Moon when we overcome all the odds.

“Building a Moon Base” is based on research by Haym Benaroya and Leonhard Bernold (“Engineering of lunar bases“)

Many types of structure have been proposed for lunar colonies. However, the main focus for mission planners center on cost and efficiency. Structures fabricated on Earth, while viable, would have to be very lightweight to allow for easy launch out of the Earth’s deep gravitational well. It is generally envisaged that the first bases to be established on the lunar surface will be built on Earth, but once a base of operations is set up, with a contingent of human (and perhaps robot) workers/settlers, local materials should be mined and habitats fabricated in-situ (i.e. built on the Moon). Some of the structures currently being considered are detailed below.

Inflatable designs

Inflatable habitats have always been a favorite, optimizing living space whilst using lightweight materials. As the Moon has no atmosphere (apart from some very tenuous gases being “outgassed” from its surface), any habitat would need to be highly pressurized to simulate the terrestrial atmosphere (to approximately 1 atmosphere or 101,325 Pa) and atmospheric gas quantities. Due to the high forces acting outwards (by the maintained gas pressure), structural integrity of an inflatable can be assured. Assuming the membrane of the inflatable is strong enough, risk of depressurization should be low.

There is however a massive problem with inflatables. In an environment as vacuum-like as the Moon’s, there is little protection from micrometeorites (small, natural space rocks or manmade space debris). Catastrophic depressurization could occur if a high velocity projectile causes a weakness in the membrane. There are some solutions, such as covering the inflatable habitats with a layer of protective regolith, and extensive fail-safes will need to be put in place.

One design (pictured left) uses inflatable “pillows” to create a cuboid shape (rather than the more natural spherical shape). Many of these pillows can be aligned and added on to create a growing settlement. They would maintain their shape by using high-tensile beams to battle against the bellowing membrane material. Protection from micrometeorites and solar radiation would be provided by regolith.

Erectables
Classic erectables have been extensively tested and are an established form of construction. With a focus on ease of assembly, one plan involves sending components into a low Earth orbit. A frame can be easily erected and act as a tetrahedral, hexahedral or octahedral shape by which to base the design of a simple habitat module. Once complete, the module could be shipped to the Moon where it will be controlled into a soft landing. This method uses existing technology and may be one of the more feasible concepts of beginning a Moon base. A basic structure could also be constructed on the lunar surface in a similar fashion.

Local materials
Ultimately, it is hoped that a settlement on the Moon will have an infrastructure capable of mining local materials, fabricating basic quantities and constructing structures with little or no input from Earth. This degree of autonomy would be required if a thriving Moon base is to succeed.

However, to maintain airtightness within the habitats, a new form of concrete would need to be manufactured. All components for a lunar concrete mix can be found on the Moon, although water (and therefore hydrogen) will be at a premium. As the Moon is sulphur-rich, a different type of concrete (minus the need for water) may be created to aid with the construction of arced and domed habitats. Some “geotextiles” may also be made via some advanced refining, creating filmy materials to seal habitat interiors.

Building using locally mined materials will most likely be one of the more advanced methods of construction on the Moon, so in the first stages at least, settlers will be dependent on the Earth for support.

Lava tubes
Ancient lava tubes under the lunar surface exist and may be utilized by colonists. Using natural cavern systems will have many benefits, principally that minimal construction would be required. Many advocates for this plan point out there are too many risks associated with above surface structures, why not use natural shelter instead? Lava tubes may be interconnected, allowing sizeable settlements, also they may be easily sealed, allowing for pressurized habitats. Lunar colonists will also be sufficiently protected from micrometeorites and solar radiation.

Rovers

To bridge the gap between an immobile base and a highly mobile rover, the first base may consist of settlers living and traveling in a roving Moon base. In fact, many designers suggest this solution may be a long-term answer to the future of a colony on the Moon. Unlike the current lunar “Moon Buggy” (pictured), future rovers would be large, accommodating several people within a pressurized cabin. Using rovers as a base may negatively affect processes only static, permanent bases can achieve (i.e. farming activities), but a roving base would allow settlers the freedom to move when and where required around the lunar landscape.

• Building a Moon Base: Part 1 – Challenges and Hazards
• Building a Moon Base: Part 2 – Habitat Concepts
• Building a Moon Base: Part 3 – Structural Design
• Building a Moon Base: Part 4 – Infrastructure and Transportation

“Building a Moon Base” is based on research by Haym Benaroya and Leonhard Bernold (“Engineering of lunar bases“)

So, we want to go to the Moon. Why? Because the Moon is an ideal “staging post” for us to accumulate materials and manpower outside of the Earth’s deep gravitational well. From the Moon we can send missions into deep space and ferry colonists to Mars. Tourists may also be interested in a short visit. Mining companies will no doubt want to set up camp there. The pursuit of science is also a major draw. For what ever reason, to maintain a presence on this small dusty satellite, we will need to build a Moon base. Be it for the short-term or long-term, man will need to colonize the Moon. But where would we live? How could we survive on this hostile landscape? This is where structural engineers will step in, to design, and build, the most extreme habitats ever conceived…

Manned missions to Mars take up a lot of the limelight insofar as colonization efforts are concerned, so it’s about time some focus is aimed at the ongoing and established concepts for colonization of the Moon. We currently have a means of getting there (after all, it is nearly 40 years ago since Apollo 11) and our technology is sufficiently advanced to sustain life in space, the next step is to begin building… In this first installment of “Building a Moon Base”, we look at the immediate issues facing engineers when planning habitats on a lunar landscape.

“Building a Moon Base” is based on research by Haym Benaroya and Leonhard Bernold (“Engineering of lunar bases”)

The debate still rages as to whether man should settle on the Moon or Mars first. Mars is often considered to be the ultimate challenge for mankind: to live on a planet other than Earth. But looking down on us during cloudless nights is the bright and attainable Moon. From here we can see the details of the lunar landscape with the naked eye, it is so close astronomically when compared with the planets, that many believe that the Moon should be our first port of call before we begin the six month (at best) voyage to the Red Planet. It also helps as we’ve already been there…

Opinion has shifted somewhat in recent years from the “Mars Direct” plan (in the mid-1990s) to the “Moon First” idea, and this shift has recently been highlighted by US President George W. Bush when in 2004 he set out plans for re-establishing a presence on the Moon before we can begin planning for Mars. It makes sense; many human physiological issues remain to be identified, plus the technology for colonization can only be tested to its full extent when… well… colonizing.

Understanding how the human body will adapt to life in low-G and how new technologies will perform in a location close enough to home will be not only be assuring to lunar colonists and astronauts, it will also be sensible. Exploring space is dangerous enough, minimizing the risk of mission failure will be critical to the future of manned exploration of the Solar System.

So where do you start when designing a moon base? High up on the structural engineers “to do” list would be the damage building materials may face when exposed to a vacuum. Damage from severe temperature variations, high velocity micrometeorite impacts, high outward forces from pressurized habitats, material brittleness at very low temperatures and cumulative abrasion by high energy cosmic rays and solar wind particles will all factor highly in the planning phase. Once all the hazards are outlined, work can begin on the structures themselves.

The Moon exerts a gravitational pull 1/6th that of the Earth, so engineers will be allowed to build less gravity-restricted structures. Also, local materials should be used where and when possible. The launch costs from Earth for building supplies would be astronomical, so building materials should be mined rather than imported. Lunar regolith (fine grains of pulverized Moon rock) for example can be used to cover parts of habitats to protect settlers from cancer-causing cosmic rays and provide insulation. According to studies, a regolith thickness of least 2.5 meters is required to protect the human body to a “safe” background level of radiation. High energy efficiency will also be required, so the designs must incorporate highly insulating materials to insure minimum loss of heat. Additional protection from meteorite impacts must be considered as the Moon has a near-zero atmosphere necessary to burn up incoming space debris. Perhaps underground dwellings would be a good idea?

The actual construction of a base will be very difficult in itself. Obviously, the low-G environment poses some difficulty to construction workers to get around, but the lack of an atmosphere would prove very damaging. Without the buffering of air around drilling tools, dynamic friction will be amplified during drilling tasks, generating huge amounts of heat. Drill bits and rock will fuse, hindering progress. Should demolition tasks need to be carried out, explosions in a vacuum would create countless high velocity missiles tearing through anything in their path, with no atmosphere to slow them down. (You wouldn’t want to be eating dinner in an inflatable habitat during mining activities should a rock fragment be flying your way…) Also, the ejected dust would obscure everything and settle, statically, on machinery and contaminate everything. Decontamination via air locks will not be efficient enough to remove all the dust from spacesuits, Moon dust would be ingested and breathed in – a health risk we will not fully comprehend until we are there.

• Building a Moon Base: Part 1 – Challenges and Hazards
• Building a Moon Base: Part 2 – Habitat Concepts
• Building a Moon Base: Part 3 – Structural Design
• Building Moon Base: Part 4 – Infrastructure and Transportation

“Building a Moon Base” is based on research by Haym Benaroya and Leonhard Bernold (“Engineering of lunar bases“)

See also:

• Lunar Base Quarterly (LBQ)
• Lunarpedia.org
• Moon Society

There’s the Earth, and the Moon, separated by 385,000 or so kilometres. Once the astronauts return to the Moon, they’ll lose all the protection of the Earth’s atmosphere and magnetic field – getting blasted by radiation and cosmic rays. Or will they? According to researchers from the University of Washington, there are times when the Earth does help shield the Moon.

One of the major risks of space travel are solar storms. These are flurries of particles blasted off the Sun at nearly the speed of light. They can arrive with almost no notice. As soon as an Earth-directed flare is seen on the surface of the Sun, the particles will arrive just minutes afterwards.

To avoid a potentially lethal blast of radiation, the astronauts will need to seek cover in a shielded base, or at least make sure there’s a mass of lunar soil between them and the oncoming storm. When they’ve only got a few minutes warning, the astronauts will be restricted to how far they can explore on the lunar surface.

Here on Earth, we’re protected by the magnetosphere, which directs the solar wind harmlessly around the planet. Astronomers have known for many years that the Moon passes through the Earth’s magnetic sphere, and could share in our protective shield.

Researchers from the University of Washington have developed computer models of the Earth’s magnetosphere, calculating the ideal times when astronauts will receive the most protection from solar storms.

There’s an additional problem with solar storms. As the particles interact with the Earth, they heat up oxygen in the ionosphere. These particles stream away from the Earth and collide with the Moon. These are moving less quickly than the solar wind particles, but they can still add to an astronaut’s radiation exposure.

Original Source: UW News Release