Are you keen to live in a lava tube on Mars?

Lava tubes are caves formed by  lava flowing and creating a channel. When the lava flow has ceased and the rock has cooled, a long tunnel is left behind.  Although the presence of lava tubes on Mars has never been proved, their existence is likely.

The pictures below have been taken by the High Resolution Imaging Science Experiment (HiRISE) tool on-board of Mars Reconnaissance Orbiter (MRO). They demonstrate holes which could be lava tube entrances.

Possible lava tube entrance observed by HiRISE - Diameter 150m - Credits: NASA

Possible lava tube entrance observed by HiRISE        Diameter: 150m – Credits: NASA

Possible lava tube entrance observed by HiRISE - Diameter 150m - Credits: NASA

Possible lava tube entrance observed by HiRISE        Diameter: 35m – Credits: NASA

Why live in a lava tube?

The Martian ground is not the coziest place for establishing a camp with explorers and sensitive materials. Mars has an atmosphere and magnetic field which are not as efficient as the Earth’s to protect humans from the hazardous space environment.  In order to live on Mars, astronauts must carry their own habitats and living equipment from Earth. This requires a large volume and mass on board the spacecraft, reducing the payload capacity for other items.

If you ever have to live on Mars, lava tubes are very nice places which offer:

  •  Protection from radiation: radiation is a big concern regarding astronaut’s health in space (major damage on DNA).  The large layer of rock would protect explorers and materials from solar radiation.
  • Constant temperature: on the surface of Mars the temperature ranges from 20°C to -150°C. This variation of temperature is very challenging for thermal engineers. Lava tubes similar to most caves provide a constant temperature which is more convenient for thermal control. In addition, the camp may benefit from natural heat and so preserve electrical power.
  • Dust protection: dust is a very important problem. It is very intrusive, adhesive, abrasive and contaminant. Dust is harmful for equipment, experiments, and astronaut’s health. It mustn’t be introduced in the habitat.
  • Presence of alien life: lava tubes represent an interesting location to find alien life or evidence of alien life. Minerals present in the lava could be a quality source of nutrients.
  • Scientific activities: caves are excellent records of past environmental conditions. Therefore they are a target area for scientific research.
Possible Mars habitat arranged in a lava tube - Credits: Cater Emmart

Possible Mars habitat arranged in a lava tube – Credits: Cater Emmart

How to choose your lava tube?

First of all, your lava tube must be solid. You don’t want  the roof to collapse while you are sleeping in your  room, or conducting experiments on Martian regolith.  You would probably also prefer to have easy access to your habitat with a natural opening. Some caves could be very comfortable but unfortunately inaccessible from the surface. You may also want to have it near to other valuable Martian point of interests. Finally, you also must check if the place is not already occupied by a tenant, like in the book “The Caves of Mars” by Emil Petaja (1965).

The Caves Of Mars - Emil Pateja (1965)

The Caves Of Mars – Emil Pateja (1965)

Europa: a better target than Mars to find alien life

At the beginning of the 17th century, few people contributed to the invention of the refracting telescope. It was the beginning of lenses capable of observing objects with a large aperture. In 1610, Galileo Galilei provided the major contribution to the design of this optical device and used it in order to observe celestial bodies. Among other observations and discoveries, he pointed the refracting telescope at the giant planet Jupiter. It was such a surprise when he discovered that Earth was not the only planet with a moon. Actually, at this time Galileo observed four of the natural satellites around Jupiter: Io, Europa, Ganymede and Callisto.

Europa, natural colours - Credits: NASA

Europa, natural colours – Credits: NASA

In 1996, Galileo the space probe made the most significant discovery since Galileo the scientist: Europa has water ice on the surface with a higher mineral content which may allow extraterrestrial life! In 1982, in his book 2010: Odyssey Two, Arthur C. Clarke imagined an ocean below Europa’s ice which hosted a form of life.

2010:Odyssey Two - Credits: D.Shire

2010:Odyssey Two – Credits: D.Shire

Europa is the sixth-closest natural satellite of Jupiter. It orbits the giant planet in three and half Earth days and is slightly smaller than the Moon. From Earth, spectroscopy helps to determine the composition of planets. The light from Europa was observed with different wavelengths which revealed that the planet was composed of silicate rock and has an iron core. The layer of water ice wasn’t detected until the space probe Galileo flew over Europa in 1996. A salty ocean covered the entire planet below the water ice layer. This demonstrates the need of space exploration: Observing and discovering features which are not possible to do remotely.

Conditions of life on Europa

This satellite of Jupiter harbors the conditions necessary for life such as liquid water, appropriate chemical elements and energy. These are essential elements for the presence of life in the form as we know it; carbon based.

By studying the Jovian magnetic field and its surface, Europa allowed us to discover some of its mysteries. It appears that the surface has been transformed by tectonic activity. Planetary scientists found evidence of presence of salty liquid water below the ice water surface.

Jupiter constantly bombards Europa with radiation. Europa’s surface is composed of water ice and other material which is transformed into oxygen, hydrogen peroxide, carbon dioxide and sulfur dioxide. These components could be valuable nutrients for supporting life.

In order to have water in liquid form, the planet must receive appropriate heat. This may be generated with the interaction of Jupiter’s gravity and its others moons Io and Ganymede. On Earth, we experience the same interaction with the Moon over oceans but regarding Jupiter’s gravity it is microscopic.

On Earth, early life appeared in deep oceans where light doesn’t exist. This means that not all life is dependent on photosynthesis.

All these elements indicate that a form of life has great chance to exist on Europa below the surface. Compared to Mars where the presence of liquid water hasn’t been proven yet, Europa seems more likely to host life.

Potential life on Europa - Credits: NASA

Potential life on Europa – Credits: NASA

Around 2022 the European Space Agency (ESA) plans to launch the space probe “Jupiter Icy Moon Explorer” (JUICE) which will explore Jupiter, Calisto, Europe and Ganymede. Regarding Europa, JUICE will look for evidence of the ocean and determine the composition of the ice. There are large expectations from this mission to provide components that could support the presence of alien life on Europa.

Because we are all Born For Space!