BARCELONA (Reuters) - A company behind plans to open the first hotel in space says it is on target to accept its first paying guests in 2012 despite critics questioning the investment and time frame for the multi-billion dollar project.

The Barcelona-based architects of The Galactic Suite Space Resort say it will cost 3 million euro ($4.4 million) for a three-night stay at the hotel, with this price including an eight-week training course on a tropical island.

During their stay, guests would see the sun rise 15 times a day and travel around the world every 80 minutes. They would wear velcro suits so they can crawl around their pod rooms by sticking themselves to the walls like Spiderman.

Galactic Suite Ltd's CEO Xavier Claramunt, a former aerospace engineer, said the project will put his company (http://www.galacticsuite.com) at the forefront of an infant industry with a huge future ahead of it, and forecast space travel will become common in the future.

"It's very normal to think that your children, possibly within 15 years, could spend a weekend in space," he told Reuters Television.

A nascent space tourism industry is beginning to take shape with construction underway in New Mexico of Spaceport America, the world's first facility built specifically for space-bound commercial customers and fee-paying passengers.

British tycoon Richard Branson's space tours firm, Virgin Galactic, will use the facility to propel tourists into suborbital space at a cost of $200,000 a ride.

Galactic Suite Ltd, set up in 2007, hopes to start its project with a single pod in orbit 450 km (280 miles) above the earth, traveling at 30,000 km per hour, with the capacity to hold four guests and two astronaut-pilots.

It will take a day and a half to reach the pod - which Claramunt compared to a mountain retreat, with no staff to greet the traveler.

"When the passengers arrive in the rocket, they will join it for 3 days, rocket and capsule. With this we create in the tourist a confidence that he hasn't been abandoned. After 3 days the passenger returns to the transport rocket and returns to earth," he said.

More than 200 people have expressed an interest in traveling to the space hotel and at least 43 people have already reserved.

The numbers are similar for Virgin Galactic with 300 people already paid or signed up for the trip but unlike Branson, Galactic Suite say they will use Russian rockets to transport their guests into space from a spaceport to be built on an island in the Caribbean.

But critics have questioned the project, saying the time frame is unreasonable and also where the money is coming from to finance the project.

Claramunt said an anonymous billionaire space enthusiast has granted $3 billion to finance the project.

(Writing by Stuart McDill; Editing by Belinda Goldsmith and Miral Fahmy)