Image: Illustration, interstellar flight
NASA/Glenn Research Center
The next 50 years of spaceflight will carry many challenges and surprises for explorers hoping to extend their reach into the cosmos. But it will also likely hold untapped riches for space science and spinoff technology that could, one day, catapult human and robotic explores beyond our own solar system and outward to other stars.
By Senior Writer
updated 1/24/2013 2:18:16 PM ET 2013-01-24T19:18:16

Exploiting the many resources of our solar system may enable humanity to venture beyond its confines for the first time, and blaze a trail to other stars.

Building a spaceship that can travel to other star systems on human timescales — over the course of mere decades — will be a challenging and expensive proposition, with costs likely running into the hundreds of billions of dollars. But the economic and technological hurdles won't be so steep if our species has begun tapping the vast riches locked up in asteroids and other bodies beyond Earth orbit, advocates say.

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"A solar-system-wide economy could kickstart research and development of the technologies that will allow us to engage in interstellar flight," said Richard Obousy, president of Icarus Interstellar, a nonprofit group devoted to pursuing interstellar spaceflight. [Gallery: Visions of Interstellar Flight]

Light-years away
Interstellar flight is so daunting because of the vast distances separating stars. The extrasolar system closest to us, for example, is the three-star Alpha Centauri, which lies about 4.3 light-years away, or more than 25 trillion miles (40 trillion kilometers).

The farthest-flung spacecraft ever launched from Earth is NASA's Voyager 1 probe, which has covered about 11.3 billion miles (18.2 billion km) since blasting off in 1977. But it would take Voyager 1 roughly 70,000 more years to reach Alpha Centauri, and its newly discovered Earth-size planet, if the probe were headed toward that particular system (which it isn't).

So traditional chemical-propulsion technology, such as that used by Voyager 1 and other spacecraft plying the solar system today, is just not going to cut it for interstellar flight.

"We need to start looking at alternatives if we're ever going to bring into reality some of the stuff that we've been dreaming about and that makes up a staple of science fiction — how to explore these new worlds beyond the solar system," Obousy told

Possible alternatives include harnessing the power of nuclear fusion or matter-antimatter reactions. Or a probe could cruise through space like a boat through the ocean, propelled by super-focused light beamed from the environs of Earth onto a gigantic sail.

Such approaches could accelerate a spacecraft to some appreciable fraction of the speed of light. But engineers may even be able to achieve faster-than-light travel by manipulating the fabric of space-time, creating a long-sought "warp drive." [Star Trek's Warp Drive: Are We There Yet? (Video)]

Researchers had thought that such a warp drive would require a power source with the minimum mass-energy of the planet Jupiter. But recent calculations by Harold "Sonny" White, of NASA's Johnson Space Center in Houston, suggest that some design tweaks could bring that figure down to the mass-energy of a spacecraft like Voyager 1, which weighed 1,800 pounds (815 kilograms) at launch.

"I might have moved this idea from impractical to plausible," White, who is also an Icarus Interstellar team member, told He and his colleagues are now building a small tabletop experiment as a first-step "existence proof" of the idea.

A solar system economy
None of these advanced propulsion technologies are close to flight ready, so any effort to build an interstellar spacecraft will require a lot of research and development work.

The costs will thus be quite high. While stressing the difficulty of estimating potential price tags at this early stage, Obousy ventured that an unmanned interstellar probe might cost several times more than the $100 billion International Space Station. And a crewed vehicle could top $1 trillion.

Those numbers might be off-putting to many governments, especially in these tough fiscal times. But tapping the riches of the solar system could help change things, Obousy said.

Asteroid mining is a good example. Scientists have estimated that a single near-Earth asteroid, the 1.5-mile-wide (2.5 km) Amun 3554, contains $20 trillion worth of platinum and other metals.

Such figures have enticed two separate companies, Planetary Resources and Deep Space Industries, Inc., to get into the asteroid-mining business within the last nine months. Both firms plan to extract from asteroids not only metals but also water, which can be split into its constituent hydrogen and oxygen — the chief components of rocket fuel.

If all goes according to plan, the companies' work could lead to the establishment of an in-space manufacturing industry that builds habitats, satellites and other spacecraft away from our planet. Asteroid mining could also help set up off-Earth "gas stations" that allow traditionally fueled craft to top up their tanks cheaply and efficiently.

These developments would help humanity extend its reach throughout the solar system, a necessary step along the path to interstellar flight, experts say.

"I think before we ever really undertake sending something to another star, we will probably have to be masters of our own solar system," Les Johnson, deputy manager of the Advanced Concepts Office at NASA's Marshall Space Flight Center in Huntsville, Ala. (and also an accomplished science-fiction writer), told

Obousy voiced similar sentiments, pointing out the economic importance of such a big footprint.

"If we can become a civilization that has vast resources at its disposal — orders of magnitude more than we have today, as a product of space exploration, space mining and the solar-system-wide economy — then we may reach a stage where an interstellar mission doesn't actually cost us that much in the bigger scheme of the gross domestic product of the solar system," he said.

Flying to another star by 2100
Icarus Interstellar aims to help humanity achieve interstellar flight by the year 2100. Obousy said he believes that this can indeed happen, despite the economic and technological hurdles that must be overcome.

One reason for optimism is the ongoing exoplanet revolution, which has shown that our Milky Way galaxy is teeming with planets. Researchers have confirmed more than 800 worlds beyond our solar system, and scientists estimate that billions more are out there.

Astronomers have confirmed a planet in the Alpha Centauri system and detected five potential worlds circling the star Tau Ceti, just 11.9 light-years away. That includes two that might be in the star's habitable zone, the range of distances from a star in which liquid water could exist on the world's surface.

The discovery of the first true "alien Earth," a planet the size of our own in its star's habitable zone, could help build a groundswell of public support for interstellar spaceflight, Obousy said. Our species might want to examine such a world up close for any signs of life. The detection of electronic signals from an intelligent alien civilization could have a similar galvanizing effect.

Overall, Obousy thinks humanity has a good shot of launching its first interstellar mission by the end of the century. As an example of our species' potential, he points to how quickly air travel became routine after the Wright brothers' ramshackle first flight in 1903.

"I think a lot of people tend to overestimate what we can accomplish in the short term, in the next five to 10 years," he said. "But they also vastly underestimate what we can accomplish in the long term, decades or a century from now."

Follow senior writer Mike Wall on Twitter @michaeldwall or @Spacedotcom. We're also on Facebook and Google+.

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Photos: Month in Space: January 2014

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  1. Southern stargazing

    Stars, galaxies and nebulas dot the skies over the European Southern Observatory's La Silla Paranal Observatory in Chile, in a picture released on Jan. 7. This image also shows three of the four movable units that feed light into the Very Large Telescope Interferometer, the world's most advanced optical instrument. Combining to form one larger telescope, they are greater than the sum of their parts: They reveal details that would otherwise be visible only through a telescope as large as the distance between them. (Y. Beletsky / ESO) Back to slideshow navigation
  2. A balloon's view

    Cameras captured the Grandville High School RoboDawgs' balloon floating through Earth's upper atmosphere during its ascent on Dec. 28, 2013. The Grandville RoboDawgs’ first winter balloon launch reached an estimated altitude of 130,000 feet, or about 25 miles, according to coaches Mike Evele and Doug Hepfer. It skyrocketed past the team’s previous 100,000-feet record set in June. The RoboDawgs started with just one robotics team in 1998, but they've grown to support more than 30 teams at public schools in Grandville, Mich. (Kyle Moroney / AP) Back to slideshow navigation
  3. Spacemen at work

    Russian cosmonauts Oleg Kotov, right, and Sergey Ryazanskiy perform maintenance on the International Space Station on Jan. 27. During the six-hour, eight-minute spacewalk, Kotov and Ryazanskiy completed the installation of a pair of high-fidelity cameras that experienced connectivity issues during a Dec. 27 spacewalk. The cosmonauts also retrieved scientific gear outside the station's Russian segment. (NASA) Back to slideshow navigation
  4. Special delivery

    The International Space Station's Canadian-built robotic arm moves toward Orbital Sciences Corp.'s Cygnus autonomous cargo craft as it approaches the station for a Jan. 12 delivery. The mountains below are the southwestern Alps. (NASA) Back to slideshow navigation
  5. Accidental art

    A piece of art? A time-lapse photo? A flickering light show? At first glance, this image looks nothing like the images we're used to seeing from the Hubble Space Telescope. But it's a genuine Hubble frame that was released on Jan. 27. Hubble's team suspects that the telescope's Fine Guidance System locked onto a bad guide star, potentially a double star or binary. This caused an error in the tracking system, resulting in a remarkable picture of brightly colored stellar streaks. The prominent red streaks are from stars in the globular cluster NGC 288. (NASA / ESA) Back to slideshow navigation
  6. Supersonic test flight

    A camera looking back over Virgin Galactic's SpaceShipTwo's fuselage shows the rocket burn with a Mojave Desert vista in the background during a test flight of the rocket plane on Jan. 10. Cameras were mounted on the exterior of SpaceShipTwo as well as its carrier airplane, WhiteKnightTwo, to monitor the rocket engine's performance. The test was aimed at setting the stage for honest-to-goodness flights into outer space later this year, and eventual commercial space tours.

    More about SpaceShipTwo on PhotoBlog (Virgin Galactic) Back to slideshow navigation
  7. Red lagoon

    The VLT Survey Telescope at the European Southern Observatory's Paranal Observatory in Chile captured this richly detailed new image of the Lagoon Nebula, released on Jan. 22. This giant cloud of gas and dust is creating intensely bright young stars, and is home to young stellar clusters. This image is a tiny part of just one of 11 public surveys of the sky now in progress using ESO telescopes. (ESO/VPHAS team) Back to slideshow navigation
  8. Fire on the mountain

    This image provided by NASA shows a satellite view of smoke from the Colby Fire, taken by the Multi-angle Imaging SpectroRadiometer aboard NASA's Terra spacecraft as it passed over Southern California on Jan. 16. The fire burned more than 1,863 acres and forced the evacuation of 3,700 people. (NASA via AP) Back to slideshow navigation
  9. Where stars are born

    An image captured by NASA's Spitzer Space Telescope shows the Orion Nebula, an immense stellar nursery some 1,500 light-years away. This false-color infrared view, released on Jan. 15, spans about 40 light-years across the region. The brightest portion of the nebula is centered on Orion's young, massive, hot stars, known as the Trapezium Cluster. But Spitzer also can detect stars still in the process of formation, seen here in red hues. (NASA / JPL-Caltech) Back to slideshow navigation
  10. Cygnus takes flight

    Orbital Sciences Corp.'s Antares rocket rises from NASA's Wallops Flight Facility on Wallops Island, Va, on Jan. 9. The rocket sent Orbital's Cygnus cargo capsule on its first official resupply mission to the International Space Station. (Chris Perry / NASA) Back to slideshow navigation
  11. A long, long time ago...

    This long-exposure picture from the Hubble Space Telescope, released Jan. 8, is the deepest image ever made of any cluster of galaxies. The cluster known as Abell 2744 appears in the foreground. It contains several hundred galaxies as they looked 3.5 billion years ago. Abell 2744 acts as a gravitational lens to warp space, brightening and magnifying images of nearly 3,000 distant background galaxies. The more distant galaxies appear as they did more than 12 billion years ago, not long after the Big Bang. (NASA / NASA via AFP - Getty Images) Back to slideshow navigation
  12. Frosty halo

    Sun dogs are bright spots that appear in the sky around the sun when light is refracted through ice crystals in the atmosphere. These sun dogs appeared on Jan. 5 amid brutally cold temperatures along Highway 83, north of Bismarck, N.D. The temperature was about 22 degrees below zero Fahrenheit, with a 50-below-zero wind chill.

    Slideshow: The Year in Space (Brian Peterson / The Bismarck Tribune via AP) Back to slideshow navigation
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