Boldly Going Nowhere

IT’S a birthright proffered by science and prophesied by “Star Trek,” “Battlestar Galactica” and a thousand other space operas: We’re destined to go to the stars. Our descendants will spread beyond this nondescript solar system and seek adventure and bumpy-headed pals in the stellar realms.

Well, cool your warp jets, Mr. Scott, because we’re not about to breach the final frontier. Piling into a starship and barreling into deep space may long remain — like perfect children or effort-free bathroom cleaners — a pipe dream.

The fastest rocket ever launched, NASA’s New Horizons probe to Pluto, roared off its pad in 2006 at 10 miles per second. That pace would be impressive in the morning commute, and it’s passably adequate for traversing the solar system, something we’ve done and will continue to do. Combustion rockets, like New Horizons, can deliver you to the Moon in a matter of days, Mars in a matter of months, and the outer planets in a matter of years. But a trip to Proxima Centauri, the nearest star beyond the Sun and 100 million times farther from us than the Moon, would consume a tedious 800 centuries or so. You’ll want to upgrade.

We’ll build faster spacecraft, of course. Many have been designed, including ion beam rockets that shoot particles from their nozzles rather than hot gas, and nuclear-powered models. The former made their debut in NASA’s Deep Space 1 mission to investigate asteroids and could conceivably cruise at 50 miles per second. Atomic rockets, whose development was halted by test-ban treaties in the ’60s, had a target velocity 20 times greater. Alas, despite these snappier speeds, such craft are still untenable for manned journeys to the stars, taking at least a dozen lifetimes to reach the nearest.

Carting humans into deep space requires technology akin to wormhole rockets or matter-antimatter engines, the standard transports of science fiction. Wormhole travel, which takes shortcuts to the stars by warping space, looks appealing on blackboards, but physicists can’t yet say whether it would ever work in practice. Matter-antimatter engines use the enormous energy released when ordinary atoms encounter their exotic, opposite numbers, demanding the creation and storage of large amounts of hard-to-contain antimatter — a Sisyphean task, to put it gently.

In addition, such sci-fi crafts would get embarrassingly bad mileage. The energy required to reach even the nearest stars in a decade or less with a very modest-size starship (say, the tonnage of the 17th-century Mayflower) equals the total energy consumed in the United States last year. At 10 cents per kilowatt-hour, that’s a fuel bill of $5 trillion.

The pace of improvement in rocketry is languid. It will be a decade before NASA’s new Orion spacecraft allows humans to revisit the Moon, a short cosmic hop. And while today’s launching vehicles are more powerful than their predecessors, the speeds are hardly impressive. The New Horizons probe cleared the pad at a clip barely twice that of the Atlas rocket that hoisted John Glenn into orbit at the dawn of the space age.

Photo

Credit
Maxwell Loren Holyoke-Hirsch

So while there’s little doubt that humanity will soon explore and eventually colonize the Moon, Mars and the satellites and asteroids of the outer solar system, sending humans beyond that is impractical for the foreseeable future.

But there’s another technology that’s developing at a breakneck clip, and with which our grandchildren could make virtual trips to other solar systems. It’s called telepresence — a collection of technologies that extends vision, hearing and touch far beyond the corporeal confines of our nervous system.

Consider that in 1965 the Mariner 4 spacecraft made the first fuzzy photos of Mars with a black-and-white TV camera boasting 40,000 pixels. The HiRISE camera now operating onboard NASA’s Mars Reconnaissance Orbiter sports 200 million pixels. It can snap photos of objects just three feet across.

An error has occurred. Please try again later.

You are already subscribed to this email.

That’s resolution comparable to what’s on Google Earth, which many people use to examine remote parts of the globe or inspect cities known only from the nightly news. Google Mars takes advantage of the high-quality imagery being collected by our robotic orbiters, enabling armchair astronauts to peruse the red planet in considerable detail without the angst of transporting their delicate protoplasm 34 million miles into space.

Photography from the Mars Exploration Rover is so good that the data have been interpreted in an IMAX film, giving audiences a near-lifelike experience in strolling the red planet’s rusty, dusty desert. The Phoenix Mars lander has sent back pictures of individual sand grains. In other words, it’s already possible for anyone to make a rigorous reconnaissance of another planet — even though not a single human has yet stomped his boots in the Martian dust.

This is not merely the tired argument over manned versus unmanned space missions. Sending humans to the stars is simply not in the offing. But this is how we could survey other worlds, around other suns. We fling data-collecting, robotic craft to the stars. These proxy explorers can be very small, and consequently can be shot spaceward at tremendous speed even with the types of rockets now available. Robot probes don’t require life support systems, don’t get sick or claustrophobic and don’t insist on round-trip tickets.

A plausible solution would be to re-energize NASA’s development of nuclear-powered rockets, with the intention of building a craft able to send clusters of micro-bots into deep space at velocities of, say, one-tenth light speed. Depending on financing and our ability to garner international cooperation, these probes could be sent off before the 21st century starts to wane. By the middle of the following century, on-the-scene data from Epsilon Eridani, the nearest known planetary system, could be in our hands.

These microbots would supply the information that, fed to computers, would allow us to explore alien planets in the same way that we navigate the virtual spaces of video games or wander through online environments like Second Life. High-tech masks and data gloves, sartorial accessories considerably more comfortable than a spacesuit, would permit you to see the landscape, touch objects and even smell the air.

Our desire to walk a landscape that basks in the light of another star, to hear the whistle of an alien planet’s wind and feel its sting on our faces, will not — any century soon — be sated by hurling massive, human-filled starships into space. Instead, we will extend our senses light-years beyond Earth with these telepresence proxies and data collectors. That’s a far more realistic version of the “Star Trek” future: to explore distant worlds, under alien suns, without leaving the familiar surroundings of our terrestrial home.

Seth Shostak, an astronomer at the SETI Institute, is the author of “Confessions of an Alien Hunter: A Scientist’s Search for Extraterrestrial Intelligence.”

A version of this op-ed appears in print on , on Page A23 of the New York edition with the headline: Boldly Going Nowhere. Today's Paper|Subscribe