In some ways, the early explorers on Earth had it easy.
They were able to travel to new lands carrying the basic tools, water and food supplies needed to survive their long journey, and then live off the natural resources of the land. Air (or a lack thereof) was the least of their problems.
In that respect, future space travelers may find the task of building colonies on the Moon or Mars more challenging; but it will not be impossible.
The atmosphere on Mars (though just 1% of that on Earth) consists mainly of carbon dioxide, which could be converted into oxygen. There is an abundant supply of metals and minerals in the crust (or regolith) of the Moon and Mars, and there appears to be large amounts of water near the moon/planet's surface.
Water is perhaps our most important resource in space. Besides sustaining human and plant life, it can be stored as a radiation shield, split into oxygen (air) and hydrogen (to make fuel for rockets and rovers, electricity for fuel cells), used for food preparation, cleaning and much more.
Unfortunately, that water isn't lying in oceans, lakes or rivers... but in ice and under ground (at least 10-100 cm beneath the surface).
To get enough of it, we would need to do some mining; and digging can be a very energy-intensive process. It may also require the force of a reasonable-sized machine, which would be difficult (and expensive) to transport.
Microwaves to the rescue!
Realizing that water boils at much lower temperatures in the near vacuum of Mars - not much above zero degrees Celsius - our team at Gilmour Space Technologies has developed a prototype rover that uses a microwave oven to literally cook the water out of the surface. (How it works.)
Working with the Singapore University of Technology & Design (SUTD), we have successfully tested the concept in a vacuum chamber under proxy Mars regolith conditions.
Our Mars Aqua Retrieval System (MARS) was the Grand Prize Winner at an international design engineering competition, and was recently featured at a National Geographic 'Experience Mars' showcase in Singapore.
Habitats and more
Of course, this is just one idea for water extraction, and more will be needed for humankind to 'live off the land' on the Moon or Mars. As mentioned before, the major technologies needed for deep space travel revolve around having sustainable life support and power systems.
To this end, we plan to build a full-sized Mars habitat analogue at the Spaceflight Academy next year, with a fully closed air system for testing long-term biological systems that recycle carbon dioxide into oxygen, generate food and clean the habitat's water and air.
These scientific tests and investigations will be conducted over a minimum of 3 years, including the use of plant materials for producing biofuels for a Mars rover, and 3D printers for replacement parts, among others.
To the stars.