Why the Moon?
- Extend human presence to the moon to enable eventual settlement.
- Pursue scientific activities – history of Earth, the solar system and the universe.
- Testing technologies, systems, flight operations and exploration techniques for future missions to Mars and beyond.
- Mining on the moon – rare earth elements (Eg : europium and tantalum)
- Space tourism.
Hazards & Challenges:
- Half the sky is continuously visible for astronomy
- Cryogenic instruments can readily be operated
- Outside workspace in extreme contrast (light)
- Practical problems regarding solar power
- Outgassing of oil, vapors, and lubricants from pneumatic systems.
- Detrimental to:
– Astronomical mirrors
– Solar panels
- Increase in dynamic friction – fusing of drill bit to lunar rocks.
- Blasting ( to loosen regolith for excavation) – blast particles can travel large distances.
Severe temperature variations
- Structural & Material Fatigue.
- Structural sensitivity to temperature differentials between different sections of the same component.
- Brittleness at very low temperatures.
No atmospheric pressure.
- Habitats have to be pressurized (15 psi)
- Raises concerns for decompression caused by accidental & natural impacts
- long-term, sustained low-level radiation.
- As damaging as a nuclear weapon detonation upon extended exposure.
- Exposed Lunar surface – 30 rem (annual) & allowable – 5 rem
- Benefit – build less gravity-restricted structures.
- Disturbing ground causes dust suspension – dust takes long time to settle and clings to surfaces.
- Conventional equipments not suitable for low gravity.
Difficulty in construction
- Importing building supplies from earth – costly.
- Modular construction and minimum local fabrication for initial term.
- Use of local materials – long term.
- Double Membrane Inflatable
- Shaping the ground.
- Laying out the deflated str.
- Pressurize outer ring.
- Install airlocks /other.
- Spray structural foam in between double membrane.
- Pressurize inside.
- Lay floor over bags of compacted soil.
- Based on Modular construction and expansion.
- 2 parts
- Components are sent into low -earth orbit – ease of assembly
- Fitted with – living quarters, instrumentation, air locks, life-support systems, and environmental control systems.
- Then shipped to moon.
Concrete and Lunar materials:
- Water is scarce.
- Sulphur Concrete
– Requires no water.
– Sulphur readily available in Moon.
- Use of Lunar regolith for shielding.
- “Geotextiles” may also be made creating filmy materials to seal habitat interiors.
- Formed after lava flow from volcanoes.
- Surface of Lava stream solidifies & molten rock inside drains away.
- Minimal construction would be required.
- Lunar Lava Tubes are huge on the Moon.
- They can be easily sealed and pressurized.
- Natural protection from
o Micrometeorite impact
o High velocity blast debris
o Extreme temperatures ( – 180 Celsius to 130 Celsius)
Lava tubes- recent news:
- Discovered by Chandrayaan I
- 1.2 km long
- Near horizontal
Lunar Bases:: Structural Design
Structures in mind
- inflatable structures
- underground burrows inside ancient lava vents
- sustaining terrestrial pressures
- using locally mined materials
- optimizes space
The key factors influencing structural designs of habitats on the Moon :
- One-sixth terrestrial gravity.
- High internal air pressure
- Radiation shielding
- Micrometeorite shielding.
- Hard vacuum effects on building materials
- Lunar dust contamination.
- Severe temperature gradients.
- easy maintenance
- inexpensive, easy to construct
- compatible with other lunar habitats/modules/vehicles
- Using lunar regolith
- lunar concrete- structures may be formed from cast regolith
- similar to terrestrial cast basalt
- highly compressive and moderately tensile building components
Benefits of Regolith
- very tough and resistant to erosion by lunar dust.
- ideal material to pave lunar rocket launch sites
- ideal shielding against micrometeorites and radiation.
- Space for habitants
- habitat height
- Optimize functionality
- space for equipment, life support and storage
- Arches – major component for habitat design as structural stresses can be evenly distributed.
- stability of the underlying material and slope angle would have to be made whilst building the habitat foundations.
- 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.
Further structural Details:
- 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.
Lunar Bases :: Infrastructure and Transportation:
- Reduced traction:1/6 gravity and the lunar soil make traction a problem just like [the Mars Exploration Rovers] Spirit and Opportunity on Mars one can get stuck easily or need to much power to get around.
- Dust: Apollo experience shows that a lot of dust is levitated by wheeled vehicles. This dust is hazardous to machines and humans when breathed in.
Mechanical and health problems of lunar dust:
- Vision impairment
- Incorrect instrument readings
- Dust coating
- Loss of traction
- Clogging of mechanisms
- Thermal control problems
- Seal failures
- The vertical take-off and landing method
- a lunar cable car
- Roads above the lunar surface using fused lunar regolith
- They provide much needed traction
- significantly reduce the amount of dust suspension
Drawbacks of the roads
- They are enormously costly
- may be very difficult to build.
- requires enormous energies, which cannot be provided by solar power alone.
- So an alternate form of energy would be required to perform such a construction.
The vertical take-off and landing method:
- Rocket-powered take-off and landing produces vast amounts of dust.
- But should there be multiple bases on the Moon, this might be a possibility
lunar cable car:
- Totally avoiding contact with the surface, thus cutting down on dust and avoiding obstacles