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Laser propulsion system - is it possible to tack?

Jun 3, 2020
Hi everybody,
I read that laser propulsion could, in future, propel spaceships without carrying enormous mass of fuel. And some beams of X-rays coming from space match such a propulsion of a theoretical extraterrestrial civilization (but natural explanations are possible).

Now, as fair as I understand, in layman terms. The theory is that a spaceship traveling between planets A and B carries little fuel itself. A powerful X-ray laser on the planet A accelerates it. Later, a similar X-ray laser on the planet B brakes it. Otherwise 99% of the spaceship mass should be fuel, spent to propel the mass of fuel itself. The arrangement however, requires that the destination B already contains an X-ray laser. So no good for initial space exploration.

My question is: can a theoretical spaceship use external laser propulsion to change direction and possibly brake? The idea would be similar to a normal ship sailing against the wind by tacking. Can this idea advance laser-propelled space exploration? Does it have any effect on interpreting the strange X-ray bursts recorded from space?

Jurek D., Switzerland

Jun 29, 2020

A normal sailing ship is able to tack because it can use the keel and rudder of the boat to push against the water it sits on in a different direction to the wind.
I would imagine you could achieve a similar effect in space if you were able to push against the interstellar medium in some way, possibly by using a magnetic field as a physical keel / rudder would need to be pretty big
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