10 Mind-blowing Interstellar Propulsion Systems

If we’re ever going to explore and eventually
colonize the galaxy, we’re going to needfunctioning propulsion systems to do it. This goes for the nearest star, or the other
side of the Milky Way. So here are 10 hypothetical interstellar propulsion
systems we might some day use to travel interstellarspace. Number 10. Light SailsLight sails at their simplest are sails that
function not on wind, but on light pressure. Lasers stationed on earth, or in space, can
exert pressure on sails. Sails in general are ancient ideas, and we
have lasers so out of all the entries on thislist, we are closest to realizing this one. In fact, there are multiple programs looking
to build and use laser-driven lightsails,including Breakthrough Starshot, which looks
to send a swarm of microprobes attached tolight sails to Alpha Centauri at as much as
20 percent of the speed of light, and getthem there in just two decades. However, scaling this up to manned capability
presents significant challenges. But as a means of exploring nearby stars,
if programs like Breakthrough Starshot aresuccessful, interstellar exploration may begin
within the lifetimes of people alive today,though one could already argue that we’re
doing that using instruments from Voyagerto study the conditions of the fringes of
the interstellar medium. Number 9. Nuclear Pulse PropulsionOver the decades there have been several proposals
to build spacecraft accelerated by nucleardetonations to reach high enough speeds for
realistic interstellar travel. The concept is simple, build a spacecraft
with a blast shield at the back and then periodicallydrop nuclear bombs out of the back of the
ship, detonate them, and that in turn pushesthe space craft along. Increasing public distaste for nuclear projects
and nuclear test bans sidelined work in thefield of nuclear pulse propulsion, but it
does provide us with a future means of interstellartravel. And, nuclear detonations in space aren’t
the problem that they are here on earth, spaceis already full of sources of radiation, though
launching the materials off of earth to fuelsuch a spacecraft does pose risk, as is often
pointed out when NASA launches radioactiveisotope powered probes such as the curiosity
rover. This type of propulsion is, in principle,
something that current technology is closeto being able to do. Number 8. StarseedThis option is effectively a nanoprobe gun. Using a 1000 kilometer long hollow tube lined
with electrodes, exploratory nanomachinescould then be electrostatically launched at
very high speed, up to one third of the speedof light. This puts a one way trip to the alpha centauri
system at roughly 13 and a half years. That’s fast, and the main advantage is that
the researchers sending these kinds of probeswould get to see the fruits of their research
within their lifetimes. There are two downsides to this method however,
number one would be the tube itself. Given it’s length, the tube would be difficult
to keep straight and would need to be keptwell away from gravitational sources in space
to keep the nanomachines from impacting thetube while being accelerated. It’s likely that the materials to create
this are yet to be fully developed. The other issue is that nanotechnology is
generally still in its infancy, so this methodlays at least decades off. But one can also imagine many types of hypothetical
nanoprobes, such as modular devices that assembleinto a larger probe upon reaching their destination. Or von neumann probes that can self-replicate
on site, or build custom equipment withouthaving to return to earth. How far this scales up, or if this could ever
be used to do more, such as 3d print customhumans on site to colonize a planet remains
to be seen in the relatively far future. Number 7. No Hurry Propulsion and Dyson’s SlingshotAs it stands, at currently attainable speeds,
it would take our current rocket-based technologycenturies to get to the nearest star system,
voyager II for example will need 42,000 yearsbefore it will come close to another star,
and it’s only ten light-years away. But over vast amounts of time, hundreds of
thousands to millions of years, the galaxyshrinks and can be fully colonized in terms
of a few million years at slower speeds. If you have that kind of time, or you’re
in a situation such as a multigenerationalship built, say, from an asteroid, then slower
methods can be used. Other possibilities include powerful rockets
launched not from earth, but from space andand also gravitational slingshotting. But if you chose your destination wisely,
you can do much more with this than you mightthink. The concept of Dyson’s slingshot comes into
play. If you can get to a certain type of binary
system, such as closely orbiting white dwarfsor even binary neutron stars, these types
of systems can be moving very rapidly. Some of that energy can be imparted to a spacecraft
passing closeby and slingshot it out on anew trajectory at much higher, relativistic
speeds. In other words, it may take a while to get
to a binary neutron star system, but onceyou’re there, you’re on your way much
faster to wherever you wish to go. Number 6. Nuclear Fusion DrivesFusion always seems right around the corner,
and has been for decades. But recent developments may be changing that
status quo. While large fusion reactors like what might
be developed from megaprojects like ITER wouldn’tseem useful in space until decades, at least,
from now, there is a lesser known, somewhatmore secretive project that may yield results
much sooner. It’s the Compact or High Beta fusion reactor
being developed by Lockheed Martin’s skunkworks. If that project works out, fusion could not
just finally be right around the corner, butthe reactor would be small enough to launch
into space. If that ends up the case, and if the idea
works, that would allow energy generationin space on unheard of scales. The International Space Station for example,
has about 75-90 kilowatts available to itgenerated by an acre of solar panels. High beta fusion reactors could produce a
hundred or more megawatts, enough to run alarge city, yet be about the size of a city
bus. With that kind of power available, goodbye
ISS, hello Battlestar Galactica. There are several ways to use fusion as a
propulsion system. One is direct thrust using the fusion reaction,
and the other would be to generate electricityfor the various electric methods of producing
thrust, such as ion drives, plasma drives,photonic drives and so on. Number 5. The Antimatter ValkyrieImagine being able to travel at 92% of the
speed of light, and then when you need it,have the means to slow back down. And unlike some hypothetical faster than light
methods of propulsion using exotic forms ofmatter, this one can be done with a material
we’ve already created here on earth, thoughit’s perhaps the most costly material on
earth to produce. Anti-Matter. Assuming that anti-Matter in the future can
be created in sufficient quantities efficientlyenough to make it worth it, you could build
the Valkyrie. How this works is that you create a small
matter-anti-matter reaction, and the exhaustfrom their total annihilation pushes you along. Then you add more anti-matter, on the order
of a 100 tons or so for the length of yourtrip, and in the process, you’ve reached
some seriously relativistic speeds. As designed, the Valkyrie works more like
a train of sorts, with the the crew compartmentsand payloads suspended between two engines
on a long tether, which has the effect ofreducing the overall mass needed to build
the ship by eliminating some of the radiationshielding needed as the engines would produce
gamma radiation. At these speeds, dust and debris in the interstellar
medium would be a problem. Shielding from space debris is accomplished
in this design by a dual use radiatior infront of the ship, droplets of liquid heated
by waste heat are sprayed in front of theship, they then fall back down cooled back
into the radiator for recycling, and the cloudof liquid in front of the ship has the effect
of shielding. Unfortunately, the biggest problem with this
design is the uncertainty over whether wecould ever find a way to manufacture anti-matter
on a large scale. Tons would be needed and it’s currently
only available in seriously minute quantities. Then you have to contain the anti-matter,
which is quite hard. New technologies would be needed and until
that changes, if ever, this method cannotbe pursued. Number 4. The Alcubierre Star DriveThis option has been thought about for a while,
and if it’s possible, it would allow notonly interstellar propulsion, but intergalactic
propulsion, faster than light travel and shieldingfrom the relativistic effects of traveling
at high speed through the normal universe. The idea is that you circumvent the speed
of light limit by effectively splitting offa piece of space time around your spacecraft
and accelerating it, and by proxy your ship,to faster than light speeds. This ship itself is not actually moving through
space time, it’s sitting stationary on apiece of space time that is moving. This is possible because spacetime itself
is not subject to the faster than light ban,and can, in principle be made to propagate
through the universe far faster than light. However, this option suffers from a bunch
of problems people have thought of over theyears. One of them is that you’d need some serious
energy to get it going, perhaps prohibitivelyso for most civilizations. But, more recent thinking is shrinking this
amount of energy further and further. Another issue is that you’d need negative
matter, which is something that the universedoes not prohibit from existing, but that’s
it. So it’s not banned, but we have no clue
how to make it, and there’s no evidencethat any of it exists naturally in our universe. Other problems include surviving the trip,
which again, as discussion of the concepthas progressed problems have seemingly cropped
up. But, if it turns out possible, then the warp
engines from star trek will seem like bicyclesin comparison. There doesn’t appear to be a hard and fast
upper speed limit for the drive, but there’salso no guarantee you could figure out a way
to slow it back down, but it would allow accessto at least large swaths of the universe. Number 3. Black Hole StarshipsIntuitively we might think that black holes
are by their very nature inherently dangerous. And, they are, in certain situations such
as if you’re falling into one. But they are also incredible objects that
could, under the right circumstances, makefor good propulsion systems. But in that case, you wouldn’t want to use
a natural black hole. Instead, you’d want to make an artificial
one and they are possible to make. One you had a black hole, you would then use
it’s hawking radiation to propel the shipessentially by creating a dish and directing
the radiation. The materials needed to shield gamma radiation
and build such a ship — it would generatea lot of heat — do not yet exist, but if
they did, a 606,000 metric ton artificialblack hole could produce 160 petawatts of
energy. With that available energy, you could reach
relativistic speeds in a matter of days. It’s still being debated in physics whether
using a black hole to power a starship isactually possible in practice. But it’s not the only way you could use
an astrophysical object to generate thrust,you can also use stars. This idea is relatively simple. Called a Shkadov thruster, it essentially
involves building half a dyson sphere, whichthen directs the stars output in one direction,
thusly moving the star itself along with thethruster. At least initially, this is not a fast way
to travel, it would take time, but a civilizationthat has nothing but time on their hands might
employ the shkadov thruster as a long-termstar management system, moving them around
to wherever they might wish. Number 2. Traversable WormholesThe concept of a possible connection, or tunnel
to another part of the universe is an alluringone in science fiction because it’s one
of the few ways that the speed of light limitmight be circumvented that’s consistent
with general relativity. It’s the traversable wormhole, and while
entirely hypothetical, there are objects innature that may, or may not, actually be hosting
wormholes, such as the singularity at thecenter of a black hole, or very tiny ones
that may form in the quantum foam. The problem with wormholes is that they don’t
really appear to be very traversable. But what could make them traversable is, once
again, negative matter. A shell of negative matter might be able to
hold a wormhole open. But, it’s somewhat unclear where you might
end up. Would it take you to some other point in the
universe?If so, what time period, as they also open
up the possibility of time travel. In fact, Kip Thorne and colleagues advanced
that a wormhole normally connecting two pointsin space, could be turned into a time machine
if you accelerate one of the openings, thoughyou could never go back to a time before the
wormhole existed. But there’s another aspect. If you could somehow open a wormhole, and
hold it open, and step through, you may notget what you expect. One last possibility for wormholes is that
they might not lead to some other point inspace-time, but rather an entirely different
universe. This is a problem, because if other universes
exist, they may have very different properties,so stepping into a universe where matter can’t
exist in the form it does here, you may simplydissolve. Number 1. The Halo DriveThis option is a very recent addition to the
list of possible star drives. In a recent paper by David Kipping, link below,
and links to an in depth video he did on thesubject and a recent interview on the subject
I did with him on Event Horizon, he proposesusing binary black holes as a method of propulsion. To make it work, you would fire a laser at
the event horizon of one of the black holesjust slightly above the surface. The gravity of the black hole would then warp
the laser around to the other side, sendingthe beam back your way, but having increased
the energy of the beam, blue shifting thelight. This more energetic light could then be used
for propulsion to relativistic speeds. This is a very efficient way to do it, since
the only energy you need to invest in is actuallygetting to the black hole. Once past that, the Halo drive is effectively
a free lunch. Also possible here is a method for slowing
down. If you travel from one set of binary black
holes to another binary black hole systemyou could use the halo drive in reverse to
slow back down. This could allow for a network of binary black
holes to serve as a sort of natural highwaysystem throughout the Milky Way. Thanks for listening!I am futurist and science fiction author John
Michael Godier currently giving a heads upagain. In about two weeks from now on Event Horizon,
my guest will be Dr. Miguel Alcubierre fora discussion on faster than light propulsion
and other such topics, going to be a goodone and be sure to check out my books at your
favorite online book retailer and subscribeto my channels for regular, in-depth explorations
into the interesting, weird and unknown aspectsof this amazing universe in which we live.