But NASA is actually putting money into investigating the idea – as well as researching an artificial gravity chamber for spacecrafts.

The space agency signed off 22 early stage technology projects this week as part of the The 2017 NASA Innovative Advanced Concepts (NIAC) portfolio of Phase I concepts.

If they're found to be workable, the space agency will allocate more research funding.

Writing about the vacuum airship, NASA says, 'This concept is similar to a standard balloon, whereas a balloon uses helium or hydrogen to displace air and provide lift, a vacuum airship uses a rigid structure to maintain a vacuum to displace air and provide lift.

'Mars appears to have an atmosphere in which the operation of a vacuum airship would not only be possible, but beneficial over a conventional balloon or dirigible.