3 ms·
People don't realise this, but you can steer perfectly fine with a solar sail. That's because photons transfer momentum not just when they hit the sail, but als
by sigmoid10 1y ago
People don't realise this, but you can steer perfectly fine with a solar sail. That's because photons transfer momentum not just when they hit the sail, but also when they are emitted after reflection. So just by turning the sail at an angle, you can create a force in any direction perpendicular to the velocity vector. Using a two sail system, you can even accelerate and slow down along a single beam path. So you could theoretically travel to mars with a constant acceleration/deceleration phase (like a flip-and-burn in the Expanse) using only one beam emitter on earth.
- kragen 1y agoHow long would it take for a person to get to Mars with a sail powered by an Earth-based laser?
- lazide 1y agoInfinite time since we have no realistic way of making such a laser at this time - and anyone trying it is likely to get nuked before they finish their massive death ray.
- kragen 1y agoStipulate that we have the laser.
- sigmoid10 1y agoDepends entirely on the power output of the laser, the dispersal length and the size, weight and reflectivity of the sail. Since we are already talking about imaginary technology, any answer between "slower than current chemical rockets" and "some significant fraction of the speed of light" could be valid.
- kragen 1y agoI don't think that is correct. I think there's a rather disappointing limit on the acceleration a laser sail can reach with known materials.
- sigmoid10 1y agoYou explicitly asked for unknown materials. Because there is no known material because such a laser does not exist. We have solar sail prototypes that were using the sun's light, but even they are far off in terms of size/weight ratio and reflectivity.