Planetary missions of the future will demand much more than just durable and flexible spacesuits.
To allow astronauts to drive and hike around the surface of another planet unencumbered, NASA engineers must cut down the weight of the life-support system that they carry on their backs. That backpack contains the batteries, oxygen and water, along with the carbon dioxide scrubber that astronauts need to survive.
The unit, which weighs about 200 pounds on Earth, is the heaviest and bulkiest of the components astronauts carry. Even on Mars, where gravity is one-third that of Earth's, the backpack would weigh almost 70 pounds -- an unacceptable burden for explorers to carry.
The Mars-exploration mission of the future will require an advanced life-support package that is compact and easy to maintain and repair. With astronauts away for one to two years, it is vital that the life-support units be reliable and serviceable, explained Robert Yowell, of the Extra-Vehicular Activity Projects Office at NASA's Johnson Space Center.
"It would have to be a user-friendly, modular design compared to what is used on the shuttle," Yowell said. "You could open the back, everything would be very logically laid out and easily accessible without a soldering iron. It would be a plug-in plug-out system."
The life-support unit will also have to be rechargeable to support extended excursions on the surface. Right now, the duration of a spacewalk is limited by the amount of consumables the life-support pack can hold. The current limit for spacewalks is 7 and a half hours, Yowell said. If time runs out while an astronaut is in the middle of a job that demands just a little additional work, there is no way to extend the spacewalk. A rechargeable system would give astronauts the flexibility they need to remain on the surface longer.
NASA is looking toward building a small rover or cart that carries the oxygen, water and power that astronauts need. It would be accessible through a quick-disconnect hose that crew members could hook up to while outside on the surface. The hose would connect directly to an astronaut's suit and, in a few minutes, would be able to fill up with enough air, water and power to support a few extra hours outside, Yowell said.
Scrubbing carbon dioxide from an astronaut's exhaled air requires a bulky canister about a foot long that weighs almost 20 pounds. The next-generation life support pack would have smaller and lighter systems for cleaning or expelling exhaled air.
"We're looking at new technologies for the Mars exploration case that would be as elegant as a laser that is tuned to, lets say, the CO2 molecule and can dissociate that cleanly and constantly as you're breathing during the EVA," Yowell said.
Although such a laser would require use too much electricity to be powered with today's technology, Yowell said, but with technological improvements such a device may become feasible within 5 to 10 years, he said.
Robotic support
With only a handful of astronauts on any given planetary mission, it will be important to spread out the workload. Exploring astronauts will likely rely on robots to perform many of the mundane tasks of surface exploration. Robotic rovers can scout the ground ahead of crew members, take pictures to catalogue the surface and carry geologic samples. They might even be able to fetch tools for astronauts that are left behind in the car.
"Look at Star Wars and in science fiction, androids and R2D2s are always very trusted companions of people. That should be the case in the future," Yowell said.
So trusted, they may even be able to play lifeguard, watching over astronauts in the field. As a safety precaution, astronauts always travel in pairs, but robotic rovers might be able to fit into the buddy system.
"If these rovers become smart enough with artificial intelligence, there's no reason why you couldn't send an astronaut out with this rover and no other person," Yowell said, "We'd like to get to that level of complexity and trust to make this within our safety guideline limits. There's no reason why that couldn't happen."
"The robotic system should be a safety net for an astronaut, ensuring that they can stay alive should anything fail on the suit, or perhaps if the person becomes incapacitated, the robotic assistant could help the person get back to safe haven," Yowell said.
Controlling it all
To control the robotic entourage each astronaut may have, it will be necessary to have hands-free communication and control systems. This will require an advanced helmet that incorporates computer systems and visual displays similar to those being used and developed for fighter pilots.
Such a system would allow astronauts to operate robots with either voice commands or through eye-movements. It might also incorporate retinal displays where visual information could be projected directly into the eye.
All these capabilities are years away, but so is any possible planetary mission. Most agree that the effort will require an Apollo-style national drive to get there.
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