Cosmos is huge. This is a really big place. We had to spend 10 years to get through our system. At the same speed to the next star to move 70,000 years. Therefore, if we intend to master at least the nearest systems, then we need to improve transport.
When it comes to launching from Earth, the only option is a rocket. Only they have enough power to escape from planetary gravity. They quickly release energy, but do not differ in efficiency.
But in space, mathematics works differently. Away from gravity and the atmosphere, slowing us down, there are many interesting options.
Go to a nuclear reactor
Rockets derive energy from burning fuel and oxygen. This is a kind of fire that people have been using for thousands of years. In the 1960s there was an idea of using a nuclear reactor. That is, such a rocket will use the heat and pressure created in the reactor. On Earth, such pressure is used to rotate a turbine or generate electricity. But in space, it can function as an engine.
NASA considers nuclear missiles as the fastest way to get humans to Mars. Modern missiles create one powerful explosion, which moves the device. But the nuclear would be able to work without stopping, followed by acceleration, which will reduce the duration of the flight by half.
NASA uses nuclear missiles as a method of delivering people to the Red Planet
Nuclear engines are efficient, but they are still based on fuel. Is it possible to exclude it from the equation?
Around our planet is concentrated magnetic field. Its power is even enough to rotate the tiny magnet of the compass needle. Increase the arrow and send it into space. So we created an electrodynamic trailer.
Such an apparatus moves through space on electromagnets with a change in its magnetic field. Charge it so that it resists the earthly, and you just push out. Turn in the opposite direction and slow down. This method is already being considered for satellites.
Without air resistance and fuel restrictions, a serious impulse could be created. Setting the right direction, it would turn out to form a real space catapult.
We catch a gravitational wave
Stretching and bending of space-time can be used for space travel
Despite the efficiency of the engines, we still can not exceed the speed of light. The closer the unit is to light speed, the more energy is needed for acceleration. Where to take the endless energy supply? The most bizarre methods offer a curvature of the speed limit of light. That is, you can stretch the space in front of the ship and collect it from behind, as in science fiction films. A ship can never destroy light speed, but in theory you can use a bend.
The only problem is that this will require an engine consisting of special matter - a type with negative mass.
While this is just an idea. We are still stuck in the era of rockets, and the bend of space-time remains on the pages of fantastic books. But 100 years ago, people in general could not believe that it was possible to break out of the limits of their own planet. Therefore, no one knows what awaits us further.