Space Hotels Could Run Ferry Service to Mars

The ultimate floating hotel, a "cycler" to carry astronauts, and ultimately tourists, in orbit between Earth and Mars, is being worked on by US engineers. Cyclers are the brainchildren of Edwin "Buzz" Aldrin, one of the two Apollo astronauts to make the pioneering visit to the moon in 1969.

These metal "hotels" would ferry people and materials across space between the two planets, aiding exploration and commercial opportunities on Mars. The first could be in business by 2018.

"Some day people will be going to Mars on a regular basis," said James Longuski, of Purdue University, Indiana, in the US. "Most people are convinced we are going to do this. The only question is when."

The first cyclers could be assembled from the external fuel tanks which are jettisoned from Nasa space shuttles. They could rotate slowly, to create artificial gravity, and their orbits could keep them sailing permanently between the planets.

On encountering the Earth or Mars the force of local gravity would hurl the "hotels" back in the other direction, at speeds of up to 13,000 mph.

A cycler with accommodation for up to 50 people would become "a permanent, man made inner solar system companion of Earth and Mars, tapping the free and inexhaustible fuel supply of gravitational forces to maintain orbit", the researchers told Nasa. They stated: "Like an ocean liner on a regular trade route, a cycler will glide perpetually along its beautifully predictable orbit."

To catch the cycler you would need to book ahead. And because the spacecraft would never stop, travellers would have to either wait at orbiting spaceports or leave Earth aboard space "taxis" that could take a week to link up.

"This is sort of like a bus that doesn't stop. When it comes by you have to run alongside it and grab on," said Professor Longuski. "But these cyclers would be like space hotels, providing all the usual creature comforts."

Scientists, backed by Nasa grants, have begun to look for plants for the long space flights which would provide food as well as being used for recycling carbon dioxide and water. A team at Cornell University has also tested menus for voyagers. The US and European space agencies are looking at the issues of weightlessness, anxiety and tedium, which would challenge explorers.

Mars is no longer a fantasy destination. A British robot spacecraft, Beagle 2 - complete with Damien Hirst artwork and a call-sign from Damon Albarn of the pop band Blur - is expected to touch down on Mars late next year.

Other entrepreneurs have begun to plan orbiting hotels, from surplus rocket casings, and space factories that could extract precious metals in asteroids and comets. Some are lobbying for a permanent moon base to provide cheap supplies of water for fuel and sustenance in space.

The first real space tourist - Denis Tito, an American billionaire - last year paid £14m for a short holiday on the international space station in orbit around the Earth. In April Mark Shuttleworth, a South African internet multi-millionaire,will spend much the same sum to leave Earth in a Soyuz taxi to the space station.

The cyclers' scientists take a long term view, since the challenges are huge. The Earth's orbit around the sun is almost circular, but Mars's orbit is elliptical. And Mars takes 687 days to go round the sun, compared with the Earth's 365 days - putting the planets periodically at opposite sides of the sun.

The distance between the two planets varies continuously, from 33m miles to 250m miles. So each cycler orbit would present a tricky timing problem. One cycler would not be enough; the scientists would want three shuttles in service.

Dr Aldrin, Prof Longuski and others have just delivered a report for Nasa's jet propulsion laboratory, which manages missions to Mars. "We are going to put in a proposal for a more detailed study to narrow down some of the choices of different kinds of cyclers, and decide which ones seem to fit into a very nice operational mission," Dr Aldrin said.

Menu for space travellers

Spacecraft could include 30 crops on board growing in temperature controlled hydroponic farms. US scientists have devised "space menus" using the plants:

Breakfast

Fresh melon, sweet potato pancakes or rice cereal with rice milk, followed by scrambled tofu

Snack

Pitta bread with peanut butter and carrot sticks

Lunch

Tomato and lime soup, sweet potato and bean burrito with fresh salsa, tofu miso dip with carrot sticks

Dinner

Carrot drumsticks, tabouli salad, potato and coriander stir-fry, zucchini loaf cake