The US space agency has unveiled two prototypes, one white model designed for exploring outside of the spacecraft on spacewalks, and a second orange suit for high-risk activity on the inside, such as launching and returning to Earth.

Spacesuit engineer Amy Ross said the new Exploration Extravehicular Mobility Unit (xEMU) for outside use had been made more flexible than before, making it easier for astronauts to move and bend.

It's so flexible that it allows users to put their arms overhead, something astronauts during the Apollo program were not able to do.

"Zippers are bad and cables are bad so we have no zippers or cables on this suit," she said at a demonstration held in Washington DC on Tuesday.

"There will be fewer seams and new materials that keep the dust out."

It also features new technology to better manage pressure and the gloves have been improved to allow greater dexterity.

"You'll remember, Neil Armstrong and Buzz Aldrin, they bunny-hopped on the surface of the moon, well, now we're actually going to be able to walk on the surface of the moon, which is very different than our suits of the past," NASA administrator Jim Bridenstine said.

The Orion suit used for launch and entry is made from fire resistant material and features a lighter and stronger helmet, with improvements to reduce noise.

Nasa aims to put the the first woman and next man on the moon by 2024 and maintain a presence with an ISS-like gateway orbiting around it, in hopes of eventually moving further into space to Mars.

Kenneth Bowersox, acting associate administrator for human exploration, recently cast some doubt on the target date for the Artemis missions to the moon, saying he would not bet anything on it.

Funding and technical challenges still need to come together in order to meet the White House-set deadline, the former space shuttle and space station commander told a congressional committee in September.

Australian Associated Press