After years of planning, NASA is finally launching a new effort to send astronauts back to the moon and then onward to Mars.

The space agency is developing a new capsule spacecraft, a super-heavy rocket to boost the capsule into space, and a moon-orbiting station that, if it deploys on schedule in the mid-2020s, could serve as humanity's main waystation for ever-longer missions farther into the solar system.

But one important piece of technology is missing: a new space suit.

Fifty-three years after astronaut Ed White stepped outside his Gemini 4 capsule on the first-ever spacewalk for an American, NASA is stuck using decades-old suits that critics say are too old, too bulky, too rigid, and too few in number for America's new era of space exploration.

"It's a serious issue," Pablo de León, a space suit-designer and professor at the University of North Dakota in Grand Forks, told The Daily Beast.

Astronauts could need as many as three different kinds of space suits for a single mission. They might wear a simple, military-style flight suit while safely inside their spacecraft. For spacewalks—extravehicular activity or EVA, in space parlance—they'd need a suit that provides pressure and breathable air and protection from radiation.

Surface missions to the moon or Mars add their own requirements. An EVA suit can be fairly rigid, for example—especially in the lower body. But if an astronaut is going to walk around on Mars, they should be able to bend their legs.

“ I want folks using the majority of their energy to do work, not fighting a gas-pressurized suit. ” — Dava Newman, former NASA deputy administrator and spacesuit designer at MIT

NASA has plenty of flightsuit options, but its EVA suits are old and dwindling in number. And the agency doesn't have any suits specifically for surface missions.

Time is running out to make up the space suit shortfalls. NASA plans to launch Exploration Mission 1, the first test of Orion and its heavy rocket, as early as 2020. The Lunar Gateway station could be ready for use five or six years later.

Despite these looming deadlines, NASA "remains years away from having a flight-ready space suit... suitable for use on future exploration missions," the agency's inspector general warned in a 2017 audit. NASA failed to respond to emails and phone calls seeking comment for this story.

Today NASA uses an incomplete mix of space suits. While riding in Russian Soyuz capsules to the International Space Station, astronauts wear Russian Sokol flightsuits, replacing the orange "pumpkin suits" that astronauts wore aboard the Space Shuttle before NASA retired the Shuttle in 2011.

Boeing and SpaceX have both designed their own, unique flightsuits for passengers aboard spacecraft they're developing, and which NASA might hire for some missions.

Crew aboard the International Space Station wear casual clothes for routine work. For spacewalks, NASA stores on the station a few Shuttle-era Extravehicular Mobility Unit EVA suits that the agency first designed in the mid-1970s. Russian crew on the station have their own, equally-aged Orlan EVA suits for spacewalks.

But no one has walked on the surface of the moon or any other planet besides Earth since astronauts Eugene Cernan and Harrison Schmitt donned A7-LB pressure suits for the Apollo 17 lunar mission in 1972. The A7-LBs deteriorated quickly in the harsh lunar conditions. Today the surviving Apollo suits are museum pieces.

NASA built 18 Extravehicular Mobility Unit EVA suits for the Shuttle program. As of 2017, just 11 of the suits were still operational, according to the NASA audit. Several suits were destroyed in the crashes of the Shuttles Challenger and Columbia.

Overlapping efforts in recent years to replace the EVA suits burned through $200 million without producing operational space suits, the audit found.

"These are very sophisticated pieces of equipment," Roger Launius, NASA's chief historian until his 2016 retirement, told The Daily Beast. "They are in themselves little spaceships." And for decades, NASA designed space suits like it did spaceships. That is to say, big and rigid.

The agency's current EVA suit is a 275-pound monstrosity with 14 layers. It comes in only three sizes: medium, large and extra-large. Poor fit raises the risk of shoulder injuries, according to the NASA audit. To prepare for the suit's 4.3-pounds-per-square-inch internal pressure and pure-oxygen air supply, a wearer must spend as long as four hours "pre-breathing" and slowly adjusting to the suit's conditions.

The closest thing NASA has to a next-generation space suit is the Z-2, a prototype suit for surface missions that borrows elements from the older, Shuttle-era EVA suit but is lighter and more flexible.

“ A new program to develop a new suit is something should have been done in early '90s. ” — Pablo de León, spacesuit designer and professor at the University of North Dakota in Grand Forks

But NASA's suit-design philosophy "has definitely run its course," Dava Newman, a former NASA deputy administrator who now designs space suits at MIT, told The Daily Beast.

With only a little NASA seed money, Newman and her team are developing a new form-fitting space suit that replaces the pressurized internal gas atmosphere of the current EVA suit with direct mechanical pressure that the suit itself directly applies to the wearer's body.

Newman's "biosuit" is lighter than NASA's current suit is, and is custom-made for each wearer. "I want folks using the majority of their energy to do work, not fighting a gas-pressurized suit," she said.

NASA could incorporate elements of Newman's design into a new generation of suits for spacewalks and surface missions. But the agency hasn't widely requested input from independent experts such as Newman ... yet. "I just want to be ready," Newman said.

De León has his own ideas for NASA's next space suit. He said that, in addition to being lighter, more flexible and easier to put on and take off, a new suit should be pressurized in a spacecraft whose atmosphere is eight pounds-per-square-inch, compared to 14.7 PSI today, in order to shorten the pre-breathing time.

And if it's going to work for spacewalks and surface missions with only minimal modification—for instance, add-on boots for the surface work—a new space suit should have as few bearings as possible. Metal bearings likely wouldn't last long in the dusty moon and Mars environments, de León pointed out.

NASA's Z-2 prototype has several metal bearings, including a large one around the waist. "That may bring you problems," de León said.

The space agency should have addressed these problems decades ago but didn’t, de León said. "A new program to develop a new suit is something should have been done in early ’90s."

Delays in developing a new space suit could become a crisis as early as 2024. That's when the Trump administration wants to retire the International Space Station. Under the best-case scenario, the moon-orbiting Lunar Gateway station should still be under construction in 2024. In that gap between stations, NASA could struggle to test a new suit design in actual space.

Realistically, the agency has between now and 2024 to design, build and test new space suits. There’s "little margin for delays," the NASA audit warned.