By Bob McDonald, host of the CBC science radio program Quirks & Quarks.

An interesting proposal has been put forward by scientists to cut down the exorbitant cost of sending humans to Mars: Don't bring them back. Surprisingly, there is no shortage of volunteers who say they would make the trip.

Leaving people on Mars, rather than bringing them back to Earth, cuts the cost of the missions by as much as 80 per cent.

While it sounds like a suicide mission, the idea behind a one-way trip to Mars is to make the crew true explorers, homesteaders who would establish the first colony on another world and become permanent residents. A suitable site would be selected ahead of time, likely close to caves that have been spotted near volcanoes on the Red Planet. Supplies and food to last two years would be sent first, then once the humans arrive, they would use ice and other the resources on Mars to live off the land.

Future one-way missions would expand the colony or establish other colonies in different interesting locations.

Technically, this could all be done by the year 2030. But would it work as a social experiment?

As we saw recently with the Chilean miners, people can survive in difficult conditions for months. But in this case, the difficult conditions on Mars will be permanent.

And Mars is a difficult place to live. There is no oxygen in the thin atmosphere, so going outside always requires a spacesuit. Even in the warmest places, temperatures barely make it above freezing and the thermometer drops to minus-80 or -90 degrees Celsius at night. Sandstorms can blanket the entire planet, blowing fine red dust into everything.  Solar radiation is deadly, so the new Martians would have to be cave people.

The proponents of the idea say it will be the natural progression of humanity off the Earth, across the ocean of space. It would even ensure the survival of the human species if the Earth should become uninhabitable.

Personally, I'd rather work on improving this planet than trying to adapt another more hostile one. But if this idea catches on, it could be taken even farther with the generation starship or Interstellar Ark. In this case, an enormous rotating cylinder, 15 kilometres long and three kilometres across, is outfitted with farms, lakes, rivers and towns that could sustain 10,000 or so residents. The space colony is sent off towards nearby stars on a journey that would take hundreds of years. Several generations later, the great, great, great grandchildren of the original pioneers would reach the new solar system.

Of course, whether people could get along with each other in a sealed environment for that long is the big question, and even if they did, there is no guarantee the people who were born in space and know nothing of planet Earth would be interested in exploring new worlds. Perhaps they would say, "Let's find the planet called Earth that is known only in legend," and turn the entire ship around.

The scientists who propose such crazy ideas are trying to find ways around the sad fact that our current rocket technology is painfully slow, inefficient and ridiculously expensive.  It takes half a year just to get to Mars, more than a decade to get out of the solar system and more than a lifetime to reach the stars. So if people are willing to dedicate their lives to spreading humanity across the universe, that's the only way it can be done at the moment.

So who would be the best candidates for a one-way trip to Mars?

The scientists suggest the crew should be made up of older people, those beyond reproductive age. Mars doesn't have an ozone layer, which means radiation damage while on the surface of the planet, as well as on the journey there, could affect fertility. Many people who have said they would volunteer for the trip say that by the time they've reached their fifties, they're ready for a change in life anyway, so why not live out the rest of their lives in a high adventure on another world?