Nutrition is elementary for human existence and it poses numerous challenges for deep-space exploration. The food currently used during space missions, despite its promises to deliver nutritious value to the astronaut's diet, will become unsuitable and unsustainable during longer expeditions. Nowadays, soil-less techniques are regularly used to grow vegetables on the International Space Station. Sustainable production of proteins remains an unsolved issue both in space and on Earth. This paper introduces a novel approach to this issue, proposing the production of proteins from fungi in space. Reasons and advantages of this approach are detailed and will demonstrate how the proposed solution can be self-sustainable in space. Furthermore, the properties of fungi can also provide solutions for water filtering and waste management, as well as other emerging applications. A roadmap is proposed, which aims to accelerate the development of the related technologies needed in space, while using them to solve pressing global challenges on Earth.