In a cavernous room at the Kennedy Space Center in Florida, NASA engineers are assembling a spaceship that in the next few years will transport humans back to the moon -- and eventually on to Mars.

It's called Orion, and it looks a bit like the capsule that brought Apollo astronauts home from their groundbreaking moon missions nearly four decades ago. It's built to carry four crew members further into space than humans have ever gone, in a cabin about the size of the average kitchen -- a kitchen with a low ceiling, that is.

NASA

Now celebrating its 60th anniversary, NASA hopes to launch an unmanned Orion spacecraft around the moon in 2020. In 2023, another will carry astronauts for the first time, looping far behind the moon's dark side, in between making two close passes of its surface.

There's an echo of the past here. This room, called High Bay, is where NASA worked on the Apollo spacecraft in the 1960s, and the facility is now known as the Neil Armstrong Operations and Checkout Building, after the first human to set foot on the moon. Then as now, the goal was to achieve things never done before, to expand humanity's reach into space.

And now it's got company. Private companies like SpaceX are also working on their own plans to go to the moon and Mars.

"We are very confident the inner solar system is going to be a vibrant place by the time NASA turns 100," said Rob Chambers, director of human spaceflight strategy for Lockheed Martin, which is building Orion for NASA.

NASA/Rad Sinyak

Aiming high

For decades there's been talk of returning to the moon and pressing on to Mars, whether simply for the sake of exploration, to set up a second outpost for humanity or to tap the resources the rest of the solar system may have to offer.

It's inevitable that a leading role would belong to NASA, which has expanded the limits of where we explore and how we understand the universe. It's had many milestones over the last six decades and across vast stretches of space -- deploying robots on Mars, sending landers and satellites to asteroids and the moons of Saturn, and dispatching probes like Voyager and New Horizons toward the edges of the solar system. The Hubble space telescope has given us incomparable views of distant black holes.

The Apollo program was one of NASA's earliest and most striking successes, held up as a symbol of America's scientific prowess and can-do spirit. In six missions between 1969 and 1972, it put 12 people onto the surface of the moon, most famously Neil Armstrong and Buzz Aldrin.

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But it's been two generations since any person has ventured beyond low-earth orbit. After the Apollo program ended, NASA's manned spaceflight efforts focused on the space shuttle program, which over three decades launched 135 missions and well over 300 people to circle the Earth. That included dozens of flights to the International Space Station, starting with the first ISS assembly mission in 1998.

"NASA has struggled with 'what's next' for human spaceflight ever since the moon landings," Planetary Society CEO and TV personality Bill Nye wrote in an email. "NASA has been stymied by the high expectations of the Apollo era with a budget that is a fraction of what it was back then."

Man on the moon, redux

Now there's renewed enthusiasm for new lunar adventures. While the Trump administration has directed NASA to set its sights on Mars, it first wants the agency to create an orbiting lunar space station, or gateway, and to set up shop on the surface of our natural satellite.

"The time has come ... [to] establish a permanent presence around and on the moon," Vice President Mike Pence said at NASA's Johnson Space Center in Houston in August. Pence is also chair of the recently revived National Space Council.

The estimated costs of such a presence could run into the tens of billions of dollars. Over half of NASA's proposed $19.9 billion budget for the coming fiscal year is set aside for lunar exploration, and Congress seems likely to deliver those fund.

But NASA and government officials are no longer the only ones with lunar ambitions.

In September, SpaceX CEO Elon Musk announced the first commercial customer for a flight around the moon in his company's forthcoming BFR rocket: Japanese billionaire, entrepreneur and art collector Yusaku Maezawa, who plans to invite a handful of artists to join him on a weeklong flight to the dark side of the moon and back in 2023. (The trip does not include a moon landing.)

Amazon founder Jeff Bezos also has a commercial rocket startup, Blue Origin. The company's Blue Moon project intends to make cargo deliveries to the moon to support activities there.

"Seventeen and a half years ago is when we started settling space [aboard the ISS]," said retired astronaut Chris Hadfield, who has served as commander of the ISS and also worked out of NASA's Astronaut Office in Houston. "The next logical step will be permanent habitation on the moon."

Lockheed Martin's Chambers says the timing is finally right to go back to the moon, thanks to advances in technology, the accumulation of operational knowledge from decades working in orbit and the enthusiasm created by high-profile missions like the Curiosity rover on Mars and SpaceX's own vision for reaching the red planet with its reusable rockets.

Allowing for a little private space

Part of the way forward for NASA in the 21st century is to pursue more partnerships with private industry, including the likes of SpaceX and aerospace industry giants Boeing and Northrop Grumman.

"This is bigger than one company, it's bigger than one country," said Chambers. "Let's all compete and make it happen."

Enlarge Image NASA

NASA and the administration have set a goal of supporting an unmanned robotic commercial lander on the moon no later than 2020, around the time Orion should be making its first test flight. From there, NASA's plan calls for establishing a human-tended lunar orbiting platform -- a lunar gateway, akin to the ISS circling Earth -- "for crews to visit from Earth, to transit to and from the lunar surface, and to depart to and return from Mars."

The agency has asked industry for ideas on how to create a gateway that could develop both technology and businesses. Chambers says possible uses include a staging area for assembling deep-space probes, communications relays and a base to robotically operate equipment on the lunar surface.

On the surface, robotic landers will first scout out potential resources, according to the plan.

"A gateway is a logical starting point to do sorties with reusable landers," Chambers said.

He and others compare the lunar gateway plan to the way humans work in Antarctica, with New Zealand often a staging stopover on the way to permanent bases on the remote and frigid continent.

Onward to Mars

Nye and Chambers both agree that the route to Mars is through a transit station orbiting the moon.

"The lunar gateway space station is a good step, but it must be designed with Mars in mind, not just the moon," Nye said.

Lockheed Martin is one of six companies, along with Boeing, Bigelow Aerospace, Space Systems, Northrop Grumman and Nanoracks, working on gateway concepts. It's also developing its own Mars Base Camp concept, a so-called "deep space transport" vehicle that would be assembled at the lunar gateway and then transport humans to the Red Planet.

"The path to Mars has always taken us past the moon," says Chambers. "The gateway is almost like a spaceport."

He envisions establishing another gateway in Mars orbit.

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The plan to build a lunar gateway isn't without controversy. One of the concept's most vocal critics is Mars Society co-founder Robert Zubrin, who refers to the moon satellite as a "lunar toll booth."

"There is no need for a lunar orbit station to go to the moon or Mars," he said. "We should create a lunar lander and start landing habitats and rovers and other payloads on the surface of the moon, and as soon as that's set up we'll land people on the surface of the moon."

Zubrin has proposed a plan for building a moon base in just four years using SpaceX's Falcon Heavy rocket, and he also advocates skipping the orbiting stations around the moon and Mars and getting to the red planet by simply taking a series of flights in a SpaceX Dragon direct from Earth.

Mars-ifest destiny?

The Trump administration and NASA have set a goal of putting boots on Mars, although details at this point are few. President Trump has cited 2033 as a target date for the first astronauts on Mars.

"We could get humans in orbit around Mars in 2033, if we decided to allocate the resources, but that is increasingly unlikely," said Nye. "The significant problem that has to be solved is how to wrangle everyone involved, the stakeholders, and apply the money where it would need to go."

NASA has had a vague roadmap to get to Mars for years, but the missing piece has been the big rocket and spacecraft to get there.

Enlarge Image NASA

While NASA aims for the 2030s, others hope to get there years sooner. Crowdfunded Mars One hopes to do so in the next decade, but has had trouble getting both funds and traction. Most notable are Elon Musk and SpaceX: Musk aims to put boots on the fourth planet from the sun in the next decade, too, and going one step farther, he recently tweeted his goal of having a "Mars Base Alpha" built by 2028.

Exactly what the base would include isn't clear, but SpaceX engineers have described an initial presence on the planet constructed at first robotically and then with help from human crew living on landed BFR rockets on the surface.

It has the makings of a new space race.

Lockheed Martin's Chambers says he's confident Orion will be the first spacecraft to take people to Mars.

"Oh yeah," he said. "This is the way that humans are going to get into Mars orbit."

Asked at a press conference about the possibility someone else's spacecraft might beat BFR to Mars, Musk replied simply: "Game on."

New tech for the occasion

While the next generation of big rockets is under development, NASA is working on a variety of technologies to help make traveling to and living in the inhospitable environments of the moon and Mars more feasible and comfortable.

These include the development of nuclear fission power, which could keep the lights on at a Martian or lunar base, and research into bleeding-edge nuclear-electric or directed energy (read: lasers) propulsion systems that cut travel times drastically.

"We're talking the idea of getting to Mars in 45 days, Jupiter in a year or the interstellar medium in 10 years," said Jim Reuter, acting associate administrator of NASA's Space Technology Mission Directorate.

That technology is likely decades away, although Reuter says nuclear-thermal propulsion systems that reduce travel times by 40 percent from today's liquid and solid rocket booster technology could be built right now.

Hadfield says we might not get to Mars as fast as Musk or NASA would like:

"I don't think 2030 is realistic because our engines aren't very good. We have to invent some things and test them and improve them," he said. "There's no great urgency, but it's inevitable."

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