Beyond Earth orbit
NASA's journey to Mars begins in the place humans have continually lived since 2000: the International Space Station. Here, in low-Earth orbit, the agency is testing technologies that will be used on future Mars missions. One such advancement is 3D printing, which allows astronauts to swap out heavy toolkits for containers of reusable powder. These printers create specialized, one-off tools that can be grinded back out of existence. During an Oct. 27 panel discussion at NASA Marshall, Niki Werkeiser, the project manager for the station's 3-D printer, said NASA intends to scale up the technology so that lunar and Martian regolith can be used for feedstock. This would drastically reduce the amount of mass that has to be carried to a planetary surface. "We're looking at large-scale printers to be able to print things such as small habitat structures, radiation shielding, storage shelters and landing pads," she said.
Another low-Earth orbit technology demo happens next year, when private company Bigelow Aerospace is scheduled to connect an inflatable habitat to the station. Gerstenmaier said NASA will test how well the habitat shields occupants from radiation. Also in 2015, NASA astronaut Scott Kelly and cosmonaut Mikhail Kornienko will spend a full year aboard ISS to further quantify how long-term weightlessness affects the human body.
The real proving ground for Mars, though, is near the moon. It is there that NASA plans to spend a large part of the 20s, learning how to live and work in lunar Distant Retrograde Orbit, or DRO. Lunar DRO is a highly stable orbit where objects can remain steady for about a hundred years. At a June 19 briefing, Asteroid Redirect Mission Program Director Michelle Gates said NASA is currently interested in a lunar DRO with an altitude of about 75,000 kilometers. That's almost a fifth of the distance between the Earth and moon—a unique orbit unlike any humans have ever visited.
For NASA, lunar DRO is intriguing for several reasons. First of all, it offers a low delta-v transfer capability, meaning it's a place where spacecraft can enter and exit the Earth-moon system without using a lot of propellant. NASA plans to establish a permanent habitat here to serve as a waypoint for Mars-bound missions.
Secondly, establishing a presence in lunar DRO is a challenging but attainable milestone. It requires NASA to master deep space rendezvous and construction techniques. Astronauts living here would be far more independent than they are in low-Earth orbit—but close enough to home to bail out in an emergency. Such a quick return would come courtesy of NASA's new Orion capsule, designed with these scenarios in mind. Orion is more robust than any capsule operating today, said Mark Geyer, the vehicle's program manager, speaking to reporters at NASA Marshall. "When you're at the moon, you're somewhere between five and eleven days away from home," he said. "Orion is built to support the crew in their seats, in their suits, in a depressurized cabin, for up to six days. So it won't be a nice ride, but they'll be safe. That's the kind of stuff you have to think about when you're a long way from home."
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Originally Posted by selvaarchi
