Any road trip requires a pit stop or two. Soon, trips to space could be no different.
NASA has quietly put out feelers for what the space agency calls an “In-Space Cryogenic Propellant Storage and Transfer Demonstration.” It sounds far more interesting in civilian speak, however -- gas stations in space.
Since the beginning of manned space flight, NASA has utilized the “one-stop shop” approach; both the Apollo missions of the '60s and '70s and the more modern space shuttles carry all the fuel they need for the duration of a mission. But it would be next to impossible for a vehicle to carry all the fuel it would need on a venture into deeper space, said Chris Moore, deputy director of advanced capabilities division for NASA.
“Instead of sending the rockets fully fueled to asteroids or to Mars, we would launch them partially fueled to get more payload into orbit,” Moore told FoxNews.com. “Then we’d top off the propellant by docking with depots in lower Earth orbit."
The system would be set up ahead of time, he said, with depots drifting idly through the blackness while waiting for a rocket to dock. "All the fuel and the propellant depots would be launched before the human mission left for the asteroids or for Mars,” Moore said.
He envisions large arrays of propellant tanks all joined together, with tanks that can be added or removed depending on the length of the deep-space mission.
To establish these zero-gravity way stations, NASA must overcome a number of obstacles. The propellant used for space flight requires extremely cold temperatures, and any solar flares or fluctuations in temperature could cause it to evaporate. So finding a means of maintaining the propellant is a top priority.
Engineers also need to come up with ways to transfer the propellant to the space flight vehicles upon docking. And plans also need to be made on how to get the gas up there in the first place -- which is potentially where private space companies could step in.
“We would launch propellants from Earth on expendable rockets,” Moore told FoxNews.com. “A commercial market could be established where companies could launch propellant into space to the depot. Then NASA could purchase propellant from those companies."
"We could create a small space economy in propellants and refueling,” he suggested.
Private companies such as SpaceX and United Launch Alliance have already launched rockets into lower Earth orbit and could potentially step up to the task of transporting gas to these hypothetical stations. Neither company would comment on future plans.
But private spaceflight companies have weighed in in the past. Boeing proposed it in 2007, for example. "If there were a fuel depot available on orbit, one capable of being replenished at any time, the Earth departure stage could, after refueling, carry significantly more payload to the Moon," reads one slide from a presentation the company made at a spaceflight conference.
Space policy advocates say that this idea has been a long time coming, noting that NASA entertained the concept as early as the '70s. James Muncy, a space policy consultant with PoliSpace, says space depots will soon become the norm when it comes to future space travel.
“We have to think of it in terms of setting up an infrastructure and looking for long-term efficient approaches,” Muncy told FoxNews.com. “People who think of space as a frontier say we should separate the idea of carrying propellant from that of carrying the spacecraft and people.”
Muncy goes so far as to say the concept is common sense, claiming the road trip analogy isn’t too far-fetched.
“Your car isn’t designed to carry 100 gallons of gas. We don’t design vehicles to do that anymore,” Muncy told FoxNews.com. “If we want to keep exploring forever, it has to be affordable and sustainable.”
“We will need the technologies eventually anyway,” added Muncy. “We can’t go to Mars without them.”