Astronaut training in earth lava tubes in 2016
Studies show that lava tubes and caves provide excellent habitats that colonists can use on Mars or the Moon.
Lava tubes are formed when low viscosity lava flows close to the surface and flattens, creating a semblance of a roof. When the eruption stops, the pipe merges, leaving a tunnel below. But there are also more complex and deeper structures that form when lava flows into already prepared cracks between the layers of rocks or cavities from early streams. Similar galleries can be seen in Iceland, Hawaii, Sicily and Australia.
Underground pipe networks can cover 65 km. Space surveys of Mars and the Moon demonstrated similar formations, as well as destroyed structures. The recent mission of GRAIL has provided new data on lunar gravity hinting at the presence of subsurface voids.
Astronaut training in lava tubes in 2016
The researchers decided to compare terrestrial, lunar, and Martian lava tubes to see how gravity affects size during formation. On Earth, they can expand to 30 m, on Mars - 250 m, and on the moon - hundreds of kilometers. These are important results because lava tunnels provide the best protection against radiation, low pressure, meteorite attacks and temperatures in an alien world. The concept of lava tubes has long been interested in, therefore, there is a PANGEA program from ESA, which teaches astronauts behavior in lava tubes in the Canary Islands. They are learning to conduct geological studies to prepare for future missions.
Checking the mineral composition in weathered rocks with a HaloSpec spectrometer
The concept of a radar system is also being developed, which should find lava tubes on the Moon directly from orbit. Radar probes with low-frequency EM waves would be able to reflect the necessary signals. This helps to accurately determine the physical composition, size and shape of the caves, as well as create a detailed map.
Artistic interpretation of radar instrument for sensing lava tubes