This story was updated at 1:40 p.m. EDT.
The first spacesuits Apollo astronauts wore on the moon 40 years ago were designed before humans ever experienced the lunar environment. While the suits did their job and protected the first moonwalkers from the harshness of space, they left some room for improvement.
On July 20, 1969, Apollo 11 astronauts Neil Armstrong and Buzz Aldrin donned their bulky suits for the first moonwalk in history. It lasted about 2 1/2 hours.
The new spacesuits being designed for NASA's return to the moon by 2020 as part of the Constellation program are set to be much more sophisticated. As second-generation moon suits, they will be sturdier, easier to move around in, and should be able to recycle resources such as oxygen and water.
Many of these upgrades will be necessary because when humans revisit the moon, they plan to stay longer.
"One of the key tenets of this return to the moon and beyond is not to go and check things out and go home," said Frank Peri, director of NASA's Exploration Technology Development Program at the Langley Research Center in Virginia. "The future of exploration is really different than it was back in the 60s."
Rather than visit the moon for hours, as in Apollo, Constellation moon missions are slated to last days and even months. So the spacesuits will have to withstand a lot more use.
The suits will also have to recycle more resources, since the spaceship cannot carry all of the oxygen and water needed for the crew's entire stay.
"Part of the sustainability of living on the moon is going to be how to recycle these things," Peri said in a phone interview. "On a three-day jaunt every little piece of stuff you bring with you, you've got to use. You can't just find garbage bins. You've got to be very careful to protect the environment of the moon for future generations."
The suits will have equipment to filter water from sweat and urine back into potable drinking water, using a similar technique to a system in place on the International Space Station. The suits will also have on fuel cells for power.
However, even though the new suits will have many added abilities, they will have to be lighter than the current suits in use for spacewalks outside the space station, because of weight limitations on the Orion Crew Exploration Vehicle that the astronauts will ride in.
"Our biggest challenge is weight and volume constraint," said Jim Buchli, Constellation Space Suit System program manager at Oceaneering International, a company that has contracted with NASA to develop the first Constellation suits. "Typically a suit that provides the protection you're looking for is not small. The current EMU [the life support backpack worn by spacewalking astronauts] on station and shuttle is over 300 pounds. We need to come way down from there."
A major limitation of the Apollo suits was their degradation due to the ubiquitous lunar dust, which wore down many instruments. It had a particularly damaging effect on the astronauts' spacesuits.
"The joints they used were practically on the edge of failure because of that abrasive dust," Peri said. "We can't tolerate that kind of failure."
The new suits will be built with new, more dust-resistant materials, with fortified joints to keep out the fine particles.
"You're likely going to see a suit that is comfortable to wear, fairly lightweight, with maneuverability so you can move within the cockpit of the Orion module and get in and out of the module," Buchli told SPACE.com. "All those things to some degree have been provided by earlier suits, but we're using new materials that are available and have better capability."
- New Video - Apollo 10: The Full Dress Run-Through
- Image Gallery - Apollo 11: The Historic Flight in Pictures
- SPACE.com Special Report - THE MOON: Then, Now, Next
Forty years after astronauts first set foot on the moon, SPACE.com examines what we?ve done since and whether America has the right stuff to get back to the moon by 2020 and reach beyond. For exclusive interviews and analysis, visit SPACE.com daily through July 20, the anniversary of the historic landing. Editor's note: This story has been corrected to reflect the effect of abrasive moon dust on astronaut equipment.