There are lots of technical problems to be solved associated with space travel and colonising a new planet. SpaceX is trying to solve some of these but there are a lot of other problems not well know. Once we solved these we can move on to the more popular subjects like near light speed space travel.
The problems to be solved:
- how to reduce exposure to radiation (cosmic rays, GCRs) while traveling with a space ship
- how to reduce exposure to radiation coming from space while living on a planet like Mars not having a magnetosphere
"The health threat from cosmic rays is the danger posed by galactic cosmic rays and solar energetic particles to astronauts on interplanetary missions or any missions that venture through the Van-Allen Belts or outside the Earth's magnetosphere.[1][2] Galactic cosmic rays (GCRs) consist of high energy protons (85%), helium (14%) and other high energy nuclei (HZE ions).[1] Solar energetic particles consist primarily of protons accelerated by the Sun to high energies via proximity to solar flares and coronal mass ejections. They are one of the most important barriers standing in the way of plans for interplanetary travel by crewed spacecraft."
The problems to be solved:
- how to reduce exposure to radiation (cosmic rays, GCRs) while traveling with a space ship
- how to reduce exposure to radiation coming from space while living on a planet like Mars not having a magnetosphere
"The health threat from cosmic rays is the danger posed by galactic cosmic rays and solar energetic particles to astronauts on interplanetary missions or any missions that venture through the Van-Allen Belts or outside the Earth's magnetosphere.[1][2] Galactic cosmic rays (GCRs) consist of high energy protons (85%), helium (14%) and other high energy nuclei (HZE ions).[1] Solar energetic particles consist primarily of protons accelerated by the Sun to high energies via proximity to solar flares and coronal mass ejections. They are one of the most important barriers standing in the way of plans for interplanetary travel by crewed spacecraft."
https://en.wikipedia.org/wiki/Health_threat_from_cosmic_rays