David Kipping

the lower mass version of a binary black hole system, essentially.

In this case, he suggested just doing gravitational slingshot, just fly your spacecraft into this very compact and relativistic binary system.

And you do need neutron stars because if there were two stars, they'd be physically touching each other.

So the neutron stars are so small, like 10 kilometers across, they can get really close to each other and have these very, very fast orbits with respect to each other.

You shoot your spacecraft through, right through the middle, like flying through the eye of a needle, and you do a slingshot around one of them, and you do it around the one that's coming towards you.

So one will be coming away, one will be coming towards you at any one point, and then you could basically steal some of the kinetic energy in the slingshot.

In principle, you can set up to twice the speed.

You can take your speed, and it becomes your speed plus twice the speed of the neutron star in this case, and that would be your new speed after the slingshot.

This seems great because it's just free energy, basically.

You don't have a nuclear power reactor or anything to generate this.

You're just stealing it.

And indeed, you could get to relativistic speeds this way.

So I loved that paper, but I had a criticism.

And the criticism was that this is like trying to fly your ship into a blender, right?

This is...

There's these two neutron stars which have huge tidal forces and they're whipping around each other once every second or even less than a second.

And you're trying to fly your spaceship and do this maneuver that is pretty precarious.

And so it just didn't seem practical to me to do this, but I loved it.

And so I took that idea and this is how science is.

It's iterative.