You can’t just go making propellantless rockets, we have laws in this universe!
Hello impossible dreamers, Trace here for DNews.
Occasionally in science news, the same story will rear it’s head, cause a big fight,
and then sink back down below the waves again.
One such story is about the EmDrive [em-drive], a type of propellantless thruster technology
that skeptics call the "impossible drive."
There are a number of different kinds of these experiments collectively called: resonant
cavity thrusters, but this one has gotten a ton of press as people try and figure out
if we can someday fly through space without actually expelling anything.
The EmDrive device itself is so simple it almost seems like a prank.
It’s basically a closed cone attached to a magnetron (the same thing in your microwave
that makes… microwaves).
According to the inventor of the EmDrive, Roger Shawyer, it works by bouncing microwaves
around inside the sealed cone.
The waves carry momentum, and when they hit the reflective surfaces of the cone they impart
their momentum to that surface.
They exert more force on the large area of the cone, creating thrust, and somehow the
drive allegedly would move in the opposite direction.
The thing is, no one has yet proven it actually works.
Thus the moniker, "impossible!"
See, this explanation leaves many physicists all hot and bothered, because to them it appears
the impossible drive is violating one of the fundamental laws of physics: Newton’s Third
Law… the one that states for every action there is an equal and opposite reaction.
By not releasing any propellant, there’s no action so how could it have a reaction…
aka -- move forward.
We’ve known Newton's Third Law for over 300 years and it’s the basis for all propulsion
technology.
Want a car to move forward?
Spin the wheels to friction your way forward.
Want your boat to motor?
Push against the water with a propeller.
Want your rocket to reach Mars?
Explode a whole bunch of fuel and shoot it out the back.
So, the way the impossible drive is supposed to work, is nothing gets out.
The microwaves just bounce around inside the cone somehow creating thrust.
If it obeyed Newton’s Third Law, the microwaves could put some pressure on the inside of the
cone and bounce around, but it would go precisely nowhere.
But, if it disobeys Newton's Third Law, and actually causes movement, then we’ve got
to rethink how we understand the universe.
Shawyer insists his EmDrive doesn’t violate the Third Law.
His explanation is since the waves are traveling at relativistic speeds, they exist in a separate
frame of reference and make the EmDrive an open system, even though no microwaves are
escaping.
Yeah, I don’t understand that either.
Some studies attempting to prove the thing works have had trouble measuring every possible
source of motion, and once the resultant thrust was suspiciously close to the margin of error.
To figure it all out, a study was presented at the Joint Propulsion Conference in 2015.
The researchers wanted to find any and every error in measurement that was plaguing the
study of the impossible drive -- anything from magnetic interference to heat movement.
At the end, they found some great results, but still throw in our favorite phrase -- more
research is needed.
So why don't we just launch one?
Then we'll know, right?
Well, Guido Fetta, CEO of Cannae Inc, a man named after two Star Wars characters almost
-- invented a similar resonant cavity drive, and wants to do just that.
Fetta is planning to launch his design inside a cubesat, likely in 2017.Typically these
satellites stay aloft for about 6 weeks before falling back to Earth.
If it lasts longer… that means it’s actually propelling itself!
If it stays up for 6 months, we’re talking about a revolution in spacecraft propulsion.
If resonant cavity drives work, then gone will be the days of heavy fuels lugged back
and forth from the ground.
Instead, electricity can be harvested from solar panels to power the magnetron!
They’d coast on the sun’s rays!
It’d be like getting free lunches all the way to Mars.
That being said, if the cubesat comes down after 6 weeks?
Well, then we know Newton’s laws are still pretty good.
For now, the EmDrive is just theoretical, but what about other possible rocket designs
for the future to help send us to Mars and beyond?
Check it out in this video here to learn more.
Does the Impossible Drive blow your mind?
What do you think about it?
Let us know down in the comments, subscribe, and keep coming back here for more DNews.