At the news conference, Lansdorp said he'd like to go to Mars himself, but he isn't because his girlfriend won't come along.
"I have a really nice girlfriend, and she doesn't want to come with me, so I'm staying right here."
Are they for real?
The idea of starting a colony on Mars in 10 years seems so out of this world that CNN contacted one of the mission's potential suppliers to check on Mars One's credibility.
"I don't think they deserve to be dismissed," said a spokesman for an aerospace company that contracted for NASA's current Mars mission.
The spokesman did not want his company named because he didn't want to damage the company's relationship with Mars One, but he felt he should talk to CNN to help put the Dutch start-up into perspective for a news audience, he said.
With space opening up to the private sector, many companies large and small are trying to get in on the game, he said. Mars One's idea is one of the most audacious ones.
Strange, dangerous mission
As far as getting to Mars, Lansdorp said his organization is in discussions with SpaceX, the company that has now completed two commercial cargo missions to the International Space Station. The idea would be to use a slightly enlarged version of the Dragon capsule and land with retro-propulsion, not by parachute.
If they get there, Mars astronauts will face a lonely life of danger, subsisting for extended periods on dried and canned food. They will get some of their water by recycling their urine.
They will have to take care of sickness and injuries themselves.
"There will be emergencies and deaths," Lansdorp said. "We need to make sure that crew members can continue without those people."
Mars astronauts will have to be mentally fit to deal with the unusual stresses, he said.
"Their psychological skills will be the main selection criteria we will use," he said.
Once selected, a group of 40 astronauts will undergo seven years of training.
The flight to Earth's neighbor, with its barren red desert landscape and thin carbon dioxide atmosphere, sounds almost worse than a lifetime on it. The crew of four will be cooped up on a rocket for seven months with a limited supply of food and water.
It also might smell bad.
"Showering with water will not be an option," according to Mars One's website.
Mars, the greatest show on Earth
Mars One plans to fund the mission partly from the sale of technology developed during the mission, Lansdorp said. It will share it with potential suppliers, which Mars One lists on its website.