With an atmosphere, Mars was a temperate planet with surface water - but that was 3.5 billion years ago. Imagine if we could help it create one again?
At The Planetary Science Vision 2050 Workshop at NASA headquarters, Jim Green - NASA's Planetary Science Division Director - is proposing launching a magnetic shield to do just that.
If that sounds a bit, um, unattainable, don't worry - this workshop is a forum where super ambitious space projects are discussed, and none are expected to be completed - or even started - until 2050.
Now, onto the magnetic shield.
The shield would be made up of a large dipole—a closed electric circuit - powerful enough to generate an artificial magnetic field - and its goal is to protect Mars from high energy solar particles.
Ultimately it would mean Mars could begin restoring its atmosphere, 90 per cent of which has been stripped away by solar particles.
Simulation models show half the atmospheric pressure of Earth could be achieved on Mars "in a matter of years". Frozen CO2 at Mars's polar ice caps would turn into gas, the greenhouse effect would start to fill Mars's atmosphere to heat the planet, and ice under the poles would melt and flood the world with liquid water.
"Perhaps one-seventh of the ancient ocean could return to Mars," Green said.