A vacuum is a volume which does not contain a significant amount of matter. Hard vacuum and soft vacuum are used for very low and slightly low pressures (relative to Earth's atmosphere) and are not exactly defined. The average surface pressure of Mars can be regarded as a soft vacuum.
In reality, no space is truly empty and there is no sharp transition between the atmosphere of a planet and the vacuum beyond. Instead the atmosphere thins smoothly outward.
Due to the lower atmospheric pressure of Mars, the creation of industrial vacuum should be easier.
- Vacuum degassing is an important process in the production of steel. By exposing molten metal to a vacuum, gasses such as carbon dioxide and carbon monoxide are released, allowing the creation of very low-carbon metals (provided that the metal has not been oxygen killed). It can also remove other contaminants such as nitrogen and hydrogen.
- Heated vacuum chambers are used in the production of spacecraft. By heating the spacecraft components in a vacuum chamber, they are allowed to outgas, which prevents excessive outgassing after they are sent into space.
- Vacuum chambers are needed to to test spaceflight equipment such as pressure suits.
- The atmosphere of Mars is a sufficient quality vacuum to serve as a good insulator. It merely needs to be contained in a space so that the winds of Mars do not blow it about. The high speed winds of Mars can move considerable heat in spite of the thinness of the atmosphere.