In science fiction, spacecrafts explore every inch of our universe.
Starships travel at warp speed across the Milky Way.
Massive space stations drift through the cosmos, harboring ships and spaceplanes from strange
planets, orbiting different suns.
Science fiction paints a pretty picture of interstellar transportation, but will humans
ever explore the universe beyond our solar system?
For the last five decades, unmanned cosmic probes have inched closer to exploring the
uncharted regions of our galaxy.
In 1973, the British Interplanetary Society designed a theoretical spacecraft to fly outside
of our solar system.
It was a fusion nuclear pulse rocket, propelled by thermonuclear bombs detonated inside a
small magnetic field.
In theory, these explosions would generate enough force to launch their spacecraft at
speeds up to 18,000 miles per second.
That’s over 510 times faster than the Lockheed SR-71 Blackbird, the fastest jet aircraft
ever built.
At breakneck speeds, Project Daedalus would shoot past Mars, Jupiter, and Saturn, break
free from the Sun’s magnetic field, and perform a one-shot fly-by of Barnard’s Star,
about six light years or 35 trillion miles from Earth.
Project Daedalus ended in 1978 without a working prototype; but the project was a crucial experiment,
which proved interstellar travel was not only possible but on the horizon.
Since Project Daedalus, several revolutionary spacecraft have made the perilous journey
to the outer boundary of our solar system, but the first was actually unplanned.
In 1972, before Project Daedalus began, Pioneer 10 was designed and launched by NASA to fly
by the largest planet in our solar system, the gas giant Jupiter.
Pioneer 10 was the first man-made object to fly by Jupiter and its icy moons, but its
journey was far from finished.
After studying Jupiter, Pioneer passed the main asteroid belt and the dwarf planet, Pluto.
Pioneer 10 discovered asteroids, comets, and icy bodies at the outer limit of our solar
system, where it studied solar winds and provided NASA with crucial information for future interplanetary
missions.
While Pioneer 10’s science mission officially ended in 1997, it remains in the outskirts
of our solar system, billions of miles from Earth, acting as an emissary for our species.
The Pioneer 10 carries a gold-anodized aluminum plaque, describing humanity and the location
of Earth for any lifeforms that may discover our probe traveling through space.
If left undisturbed, Pioneer 10 is aiming for the red star Aldebaran, a journey lasting
approximately 2 million years.
In 1973, a sister spaceship, the Pioneer 11, followed its predecessor on the long journey
to interstellar space.
Pioneer 11, carrying a second golden plaque, ended its science mission in 1995.
Today, Pioneer 11 is another ghost ship drifting through our galaxy.
Unfortunately, contact with both Pioneer 10 and Pioneer 11 has been lost.
In the 1970s, NASA launched two more spacecraft, Voyager 1 and Voyager 2, both designed to
fly to the outer limit of our heliosphere.
The heliosphere is a “bubble” around our solar system at the edge of the sun’s magnetic
field, which commonly defines the boundary between stellar and interstellar space.
On its way to the edge of the heliosphere, Voyager 1 photographed the surfaces of our
gas giants.
It discovered active volcanoes on Io, one of Jupiter’s moons, and closely examined
the Rings of Saturn.
Similarly, Voyager 2 researched Uranus and Neptune, becoming the first spacecraft to
directly observe either of these distant planets.
In 2012, forty years after its departure from Earth, Voyager 1 surpassed the heliosphere
and entered interstellar territory.
Voyager 2 followed a mere six years later.
Like Pioneer 10 and 11, both Voyager probes are now floating away from our solar system,
traveling deeper into interstellar space.
Years after the Pioneer and Voyager missions, NASA initiated Project Longshot, which designed
a theoretical spacecraft intended to enter the orbit of Alpha Centauri B, a star similar
in mass and diameter to our Sun.
Alpha Centauri B is located in a triple star system over 4.3 light years from Earth.
It would have taken their craft over 100 years to cross this unfathomable distance and four
more years for data to reach our planet.
Another near-interstellar ship, designed by NASA’s New Horizons, launched in 2006 and
surpassed Pluto in 2015.
Four years later, it arrived in the Kuiper Belt to examine ancient, miniature worlds
made of rock and ice.
Its research supplied NASA with a critical glimpse into the formation of young solar
systems.
By 2043, New Horizons may enter interstellar space, where it will conduct a detailed study
of space outside the heliosphere.
The next interstellar spacecraft will not launch until at least the 2030s.
NASA plans to slingshot a 1700-pound, nuclear powered spacecraft around Jupiter and again
around the Sun to propel this probe out of our solar system.
The spacecraft is called Interstellar Probe, and it will travel 92 billion miles in just
seven years.
That’s 79 billion miles further than Voyager 1 and Voyager 2 in a fraction of the time.
Another project, called Breakthrough Starshot, proposed a fly-by of an exoplanet called Proxima
Centauri B, over 4.2 light years from Earth.
Project Starshot theorized an ultralight, proof-of-concept rocket named Star Chip.
Star Chip features a light-powered propulsion system that reaches speeds up to 37,000 miles
per second.
Though Star Chip remains conceptual, its innovative propulsion system may lay the foundation for
interstellar travel in the next century.
Another creative propulsion system is the EmDrive, also known as the Impossible Drive.
The EmDrive is a theoretical thruster that uses reflected microwaves to create huge amounts
of thrust without using a propellant like gasoline; thus violating several laws of physics,
including the conservation of momentum.
There is no working design for the EmDrive, but NASA has built and experimented with several
prototypes.
So far, the Impossible Drive has lived up to its name.
The EmDrive may be physically impossible, so aerospace engineers have theorized another
propulsion system, replacing nuclear reactors with antimatter thrusters.
According to NASA, antimatter is the most powerful source of fuel known to humanity.
For comparison, a nuclear spaceflight to Mars would consume tons upon tons of chemical fuel.
The same journey, aboard an antimatter spacecraft, would require only tens of milligrams of antimatter.
Unfortunately, antimatter is rare, unstable, and incredibly expensive.
This brings us to a staple of science fiction, which has become synonymous with interstellar
spacecraft over the years: will spaceships ever warp through our galaxy at the speed
of light?
There aren’t any warping starships on the horizon, but one NASA scientist has designed
a warp drive on a theoretical craft called the IXS Enterprise.
Named and modeled after the famous fictional starship, the IXS Enterprise uses hypothetical
particles called exotic matter to travel faster than the speed of light—a feat no human-made
spacecraft has ever accomplished.
In the last 50 years, we have explored and studied the outer boundary of our solar system,
breaking through the heliosphere into interstellar space.
Now, leaders in the field have set their sights on star systems and exoplanets trillions of
miles from Earth.
We may not be able to warp across the Milky Way anytime soon; but, over time, as we experiment,
innovate, and explore, our spacecraft may travel out of our solar system and beyond.