Just a thought.
The technology required to make a tunnel with air outside and vacuum inside is almost the same as the technology to make a tunnel with vacuum (The Moon) or very low pressure (Mars) outside and breathable air inside.
It makes sense to practice on Earth before you try it on another planet .
The technology required to make a tunnel with air outside and vacuum inside is almost the same as the technology to make a tunnel with vacuum (The Moon) or very low pressure (Mars) outside and breathable air inside.
It makes sense to practice on Earth before you try it on another planet .