One day, when earth is destroyed by war or rising seas or a wayward asteroid, humanity will be extinguished—and along with it reality television, baseball stadiums, and thousands of recipes for guacamole, with and without peas.

Unless, that is, we’ve established a colony somewhere in space.

“History has shown that extinction events happen on Earth,” Pat Troutman, a senior technologist at NASA’s Langley Research Center, told me. “We need to establish a second independent biosphere for the future of humanity.”

That idea may sound far-fetched, but scientists are working hard to make it a reality. What would it take, and how might we use the resources beyond Earth’s atmosphere? I recently talked with aerospace engineers, entrepreneurs, and researchers to find out what our future in space will look like, in the near term and in centuries to come.

1. Fast Flights

Private aerospace companies are developing reusable spacecraft, which will dramatically cut the cost of launches, because we won’t need to build a new vessel each time we want to leave Earth’s atmosphere. Elon Musk’s SpaceX, for example, is on the brink of launching a reusable spaceship. Such vessels may soon make commercial spaceflight possible: Companies such as Virgin Galactic and Xcor are already accepting reservations for suborbital flights.

Such flights will be quick—Xcor’s will last about half an hour, Bryan Campen, a spokesman for Xcor, told me. Passengers can expect to be in zero gravity within five minutes of takeoff. After floating for another five or so minutes, they will descend back to Earth, experiencing 30 seconds of teeth-gnashing 4G reentry—about the same as on an intense roller-coaster ride—before gliding to the ground. These flights will take off and land in the same spot, but within a few decades, spaceflight could become the fastest way to travel internationally—making it possible to get from New York City to Tokyo in 90 minutes, Campen said.

2. Crowded Skies

As the cost of launching rockets comes down, more people will be able to participate in aerospace ventures. Already, universities and research groups can send up CubeSats—satellites about the size of a bread box—for as little as $100,000, a fraction of the tens of millions of dollars a satellite launch usually costs.

As more organizations send satellites into space, however, collisions become more likely. In 1967, 10 years after Sputnik’s launch, about 2,500 objects (satellites, used rockets, and debris) were orbiting Earth; now there are more than 20,000, according to Colonel John Giles, the commander of the Joint Space Operations Center, which identifies and tracks objects in space. A two-centimeter piece of debris can cause as much damage to a satellite in space as a speeding Jeep would on Earth, Giles told me. The U.S. military is developing a “space fence”—a radarlike system expected to be operational by 2018—to warn of impending collisions and beginning to plan for a time when adversaries might try to take out satellites that are crucial for GPS and communications.

3. Men on the Moon

Though no American has set foot on the moon since 1972, China recently landed a rover there and plans to eventually set up a permanent lunar base. In many ways, the moon is a good place for a colony—it has water, and its soil could be mined for minerals and oxygen. The moon would also make a good jumping-off point for exploring the rest of the solar system. Its gravity is about one-seventh that of Earth, so launching spacecraft there would require much less energy.

Chris Impey, an astronomy professor at the University of Arizona and the author of Beyond: Our Future in Space, thinks we may one day build a “space elevator” on the surface of the moon in order to make lunar launches even easier. The idea sounds like something out of a Roald Dahl book: A giant tapered cable made of superstrong material would reach 35,000 miles into space. Solar-powered elevator cars would climb up the cable, delivering spacecraft into the moon’s orbit. “Serious engineers have been investigating this for half a century,” Impey said. “We could almost build it right now.”

4. Missions to Mars …

Many scientists think Mars, which has large underground glaciers, could be our best bet for a permanent colony on another planet. But the obstacles to living there are daunting. Humans can’t breathe the air, and the planet’s frequent dust storms would make farming difficult. Solar radiation is another problem, and sending messages to Earth (via radio waves traveling at the speed of light) can take more than 20 minutes, depending on where the planets are in their orbits.

Still, scientists, architects, and engineers are brainstorming ways to overcome those obstacles. ZA Architects, a Ukrainian firm, has drawn up plans for structures made out of Martian soil; robots could be sent ahead to build them. Other researchers propose inhabiting Mars’s lava tubes—underground caverns likely formed by volcanoes—since the tunnels also provide protection from solar radiation and dust storms and would keep the temperature relatively constant. And NASA is testing an inflatable habitat that could be deployed on the surface of Mars.

If a group of humans were to live on Mars for centuries with little or no contact with Earth, they would likely evolve, eventually becoming a different species, Impey told me. Because Mars has less gravity, scientists believe humans would slowly grow taller and their cardiovascular systems would become weaker. They’d also have less body hair (because they’d have to stay indoors or wear space suits, they wouldn’t need the protection from the elements), and their controlled diet might result in smaller teeth. But that’s assuming, of course, that humans can reproduce in Mars’s gravity—an untested proposition.

5. ... And Beyond

In or near the moon’s orbit, there exist a few spots, called Lagrange points, where an object is pulled neither to the moon nor to Earth. A space station orbiting one of these points could stay in place for a long time without floating away.

Eventually, Pat Troutman told me, one of those areas could serve as a harbor for ships going out farther into the universe, a sort of Rotterdam of the solar system. Resupplying and refueling would be costly from Earth, but, aided by robots, astronauts could pull a large boulder from an asteroid, tow it to a stable area, and mine it for water and oxygen, which could be turned into rocket propellant, Troutman said.

The dwarf planet Ceres, the largest object in the asteroid belt, may have big reserves of water, making it a potential base for more refueling, Troutman told me. And if Mars turns out to be uninhabitable, the Jovian system—Jupiter and its moons—might be a good alternative, he said. It, too, has water, and is largely protected from the sun’s radiation.

The universe contains an almost incomprehensible number of stars—our galaxy alone has hundreds of billions, and there exist hundreds of billions of galaxies—and an even greater number of planets. Current technology isn’t very good at determining which of those planets might be habitable—or already inhabited, Sara Seager, a professor of planetary science and physics at MIT, told me. But our view of the galaxy could become a little clearer in 2018 with the launch of the $9 billion James Webb Space Telescope. It will sit 1 million miles from Earth, where it will search for gases that look out of place in the atmospheres of other planets, signaling vapors that might be produced by other life-forms.

Sending a probe is likely the only way to know for sure whether extraterrestrial species exist. But even traveling at one-tenth the speed of light, which some physicists believe might be possible, getting to the nearest star—25 trillion miles away—would take about 43 years. (Getting to the moon at that speed, by comparison, would take about 13 seconds.)

Some physicists theorize that humans could one day get to far-off stars faster by warping space-time—essentially pushing a spacecraft forward by rapidly expanding the empty space behind it. The theory is unproved, and the process would require massive amounts of energy. Still, many scientists remain optimistic about the possibility of a manned mission beyond our solar system. “I have no doubt it’s going to happen,” Troutman said. “Just maybe not in my lifetime.”

A Brief Chronicle of Life in Space
130 B.C: Hipparchus, a Greek astronomer, draws the first accurate map the stars.
1869: Edward Everett Hale’s story “The Brick Moon,” published serially in this magazine, is believed to be the first fictional account of a space colony.
1918: The rocket scientist Robert Goddard lays out a plan for space colonization. He seals his notes, and they’re not published for 50 years.
1947:Fruit flies are the first creatures to leave Earth’s atmosphere.
1969: Neil Armstrong and Buzz Aldrin walk on the moon.
1998: Construction begins on the International Space Station.
2051: The first Mars colony is established.