Group pushes Earth-Mars transit system

WEST LAFAYETTE, Ind., Feb. 5 (UPI) -- Parked in perpetual orbit between Earth and Mars, a futuristic space transit system pioneered by Apollo astronaut Buzz Aldrin is among the proposals NASA will be considering for an advanced concepts study grant.

"Everyone understands and believes that someday we will have people on Mars but how will they get back and forth? We don't want to do it in a flags-and-footsteps method like how we went to the moon. There was no foundation laid to continue going there," said James Longuski, a Purdue University aeronautics and astronautics professor who is working with Aldrin to develop the transportation system, which is called a cycler.

The team primarily is focused on identifying and developing the trajectories that would keep a spaceship traveling between Earth and Mars with little more than slight steering tweaks to stay on course.

"The cycler essentially is in orbit around the sun and makes regular flybys of Earth and Mars," Longuski said. "Once you put your vehicle into a cycler orbit, it continues on its own momentum, going back and forth between Earth and Mars. You may need to carry some propellant for an occasional boost, but it's pretty much a free trip after that."

Passengers and supplies would be ferried from Earth or Mars to the cyclers by reusable small spacecraft. The cyclers themselves would be crafted from spent fuel tanks from the space shuttle and/or other launchers.

"This is considered pretty advanced, said Bob Bishop, with the University of Texas. "We haven't even gone to Mars with humans once, but there are a few very far thinkers at NASA who are interested in this."

Aldrin and his colleagues are submitting a proposal to NASA's National Institute for Advanced Concepts next week for initial funding.

"We are going to put in a proposal for a more detailed study to narrow down some of the choices of the different kinds of cyclers and decide which ones seem to fit into a very nice operational mission," said Aldrin, who first presented his idea for spacecraft flying in cycling trajectories to NASA in the late 1980s.

Advances in computer software enabled the team to refine flight paths to slow the cyclers' speed as it approached the Earth or Mars. Earlier models showed the spaceships would be moving so fast as they whipped around the planets that it would require too much energy for ground-launched capsules to catch up.

Ideally, the system would include several cyclers, so that passengers could catch a spaceship on the short leg of its perpetual volley between Earth and Mars. Like the planets themselves, the cyclers' path around the sun would vary over time relative to other planets and spacecraft in orbit.

Even on the fast track, the interplanetary trek would take at least six months. Passengers need not be uncomfortable during the ride, however.

"We want to build a home like a hotel with all the creature comforts to make it livable in space rather than spam-in-a-can," Longuski said.