Trump wants the US to land astronauts on Mars soon. Could it happen by 2029?

A German aerospace engineer challenged the feasibility of a crewed mission to Mars on board Starship .

The main problem is mass, the ability to recycle food, water and air.

The more that can be recycled, the smaller the amount of supplies that have to be taken on the journey.

"A Mars mission will be the greatest undertaking that humans have ever done," he said.

Astronauts going to Mars would receive radiation doses up to 700 times greater than what they would receive on Earth .

Microgravity wreaks havoc on the body, evolved as we have to live in Earth 's gravity, not in space.

There are also issues concerning the microbes that they will take with them.

A new report suggests that we are not anywhere near ready to mount a successful crewed Mars mission.

It suggests that uncrewed missions should be launched first to test the reliability of the technology for making oxygen and rocket fuel, for example, or for growing crops on Mars .

Maiwald 's team say that this is mandatory, since there's no way a successful mission can be launched without accomplishing this.