Humanity will be the multi-planetary species, and our first outpost will be the Moon. The Moon is not as hospitable as the blue planet, which has hosted life for millions of years. Moon has no magnetosphere to protect its face from solar winds. Uncertain solar winds can cause a huge amount of charged particles to blow outwards. On the far side, the Chinese moon lander, Change 4, revealed the average cosmic radiation levels as 1369µSv in 24 hours or 60µsv/hour (Sievert is the unit of equivalent radiation dose). Comparing these levels with a normal man on Earth that receives 3-8 µSv in 24 hours is almost 150 to 200 times less than the Moon; how the permanent settlers (Astronauts in the initial phase) are going to deal with scorch-ing charged cosmic particles. Charged particles such as Galactic Cosmic Rays (GCRs), acceler-ated by the supernova explosions, contribute about 75% of the total lunar radiation. 1-Sievert is the accumulative lethal dose within a short period to cause deterministic damages like Cancer and organ failures.
Apollo to Artemis
Spacecrafts of the Apollo program had radiation monitoring tools on board that recorded accu-mulative doses from Earth to the Moon, on the Moon, and back to the Earth. No radiation data was made public from the Apollo program in detail. Apollo 14 mission astronauts, on average, received 14mSv equivalent dose for the whole mission and 178mSv for Skylab 4 mission. It is highly necessary to conduct an extensive study to measure the radiation levels on the Moon and deep space and their potential impact on humans. NASA endorsed the radiation levels from the Chinese lander as compliant with Lunar Reconnaissance Orbiter’s (LRO) surface thermal moni-toring. Now humans are going back to be the permanent settlers of Luna by the end of this dec-ade (Artemis Program). Artemis-I is planned to launch in late August, with several CubeSat (small cube sized satellites) onboard, one of which is Bio-Sentinel. Bio-Sentinel has some yeast cells for testing strong space radiation effects on human DNA as yeast has similar biological ef-fects of radiation to human DNA. There are many problems to deal with on the lunar surface. These include solar radiation, low gravity, micro and macro meteorites, ecosystem, power, pres-sure, and temperature extremes. Daytime is blazing hot, up to 120C, and at night, the chilled frenzy reaches -130C. This article will discuss the Habitat ideas for the lunar outpost.
Radiation Levels at ISS:
Radiation exposure for astronauts out of the Earth’s atmosphere can be experienced at Interna-tional Space Station. The radiation level at ISS is about 550µSv in 24 hours, almost one-third of that on the Moon’s surface. The annual dose limit for astronauts is 50,000µSv or 50mSv and the lifetime limit is 1000000µSv (1 million micro-Sievert) (NASA Standard 3001 Volume 1). Ini-tially, the same limits are set for the moon crew members. No radiation-induced long-term effects on any astronauts who spend months on ISS, but microgravity-induced effects appear as bone diseases. Experiences from ISS spaceflights and Artemis program study will help keep early moon settlers safe.
How Many Days Can Be Spent On Moon?
The radiation level on the Moon measured by the Chinese lander is what an astronaut will get inside the spacesuit. If we calculate the number of days an astronaut can safely spend on the Moon according to the latest radiation levels, it will be 36 days or 875 hours out of lunar habitat to reach the limit of 50mSv. If an astronaut spends 5 hours a day on the lunar surface out of habi-tat, it will be 180 days or six months of moonwalk to reach the annual dose limit which is just the limited radiation time. Then, there are other factors to consider like temperature extremes and microgravity effects on the body,s safe.
extreme space weather like Sun storms, and return trip cost. This plan has no emergency condi-tions like unwanted projectiles, meteorites, and solar particle ejections in the maximum solar phe-nomenon.
Moon Habitat Ideas
With all the above space weather conditions, there are multiple ideas for building safe habitats. Inflatable ones, though temporary and prone to meteorite impacts and low protection against ra-diation, will be an option for the short term. Inflatable habitat will be easy to port from Earth and should be pressurized enough to simulate the Earth’s surface pressure (101.325kPa). Because of the high logistics cost, building the structures from the lunar regolith will be the most cost-effective.
Moon Village
Skidmore, Owings and Merrill (SOM) are working with ESA on developing a semi-inflatable habitat. SOM showed their concept of beyond the Earth habitat in the International Architectural Exhibition in Venice. Retired NASA astronaut Jeffrey Hoffman, currently working at MIT as a professor of astronautics, gave consultations to this SOM company for the “Moon village” habi-tat. They have a complete plan and layout for settlement on the Shackleton crater rim. This crater near the south pole has many potential advantages like no extreme temperatures, permanently under shadow areas, access to polar water ice and solar power.tive.
There is a need for a new type of concrete from materials available readily on the moon-like Sul-phur. 3D printers for building these habitats for lunar regolith are under development. 50 to 80 centimeters of moon soil layer is necessary to protect against harmful radiation. This layer can be applied over pressurized inflatable bags to protect against depressurization by high projectiles. Another idea being worked on is a lightweight structure of metal that can be put into shape in low earth orbit, and the whole module is shipped to the Moon for a soft landing. However, how to create the concrete-like material using moon regolith without the need to have water.
SmartHabs
NASA has spent $15 million collaborating with Purdue University’s Resilient Extra-Terrestrial Habitats Institute to develop Moon habitats. NASA called these SmartHabs. SmartHabs can ac-commodate up to 10 people for a normal living space, like sleeping, bathing, agriculture, exercise, dining, Etc. NASA and RETH team plan to build these SmartHabs under lava tunnels that sub-surface the moon land. The main goals of this team are to design and build a resilient structure against any worst case, self-monitoring and correcting in case of any failure in the life support system using robotic engineering.
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Lava Tubes Habitat
A paper published by Tyler Horvath, a PhD student at the University of California, Los Angeles Geophysical Research Letters Journal, based on data acquired by the LRO, mentioned a new natural way of habitat on the Moon. The Lava tubes or tunnels under the Moon’s surface created billions of years ago can be the best place to hide from radiation and meteorites. |
LRO data shows that permanently shadowed pits of collapsed lava tubes have an ideal tempera-ture range of 17C. Robotic exploration and study are being done for similar lava tubes on Earth in Hawaiian waters. Another study by JAXA (Japanese Space Agency) confirmed that lava tubes in the Marius Hills region on the Moon could protect the settlers from radiations and impacts of meteorites. This study is based on JAXA’s SELENE spacecraft through radar observations.
Saqib ALi
Saqib Ali is a content writer who has been writing about space science in various forums for the past few years. He has a master’s degree in computer science