Indeed. I'd like to also add, in case it gets brought up, that there is a reaction drive that converts energy to thrust -- and it's called a photondrive. The problem with using straight energy for thrust is that it takes an absolutely ludicrous amount of power to generate even small amounts of thrust.
Wouldn't this be good for a deep space probe though, since it can just accelerate forever (even if the acceleration is slow) and eventually attain huge speeds since it doesn't ever run out of fuel?
Except the acceleration is too low for even that, and it'd likely end up more efficient to use even something like an antimatter pion drive. Hell, you might be able to even get more thrust from something as low-acceleration as a plasma sail and simply "sailing" around stars en route to your destination, making use of gravity assists. It largely depends on how much power one's willing to expend on the photon drive.
For a quick calculation, let's assume we have a turbine from the largest dam in the world, the Three Gorges Dam. They weigh 6,000,000 kgs and output 700 MWs each. Just from those stats (and neglecting pesky stats like where the fuel is coming from or the engine weight), it would output 2.3 newtons of thrust for a total acceleration of (2.3N = 6,000,000 kgs * x m/sec^2) 0.000000383 m/sec^2, or 0.000000039 Gs. To put that into perspective, using the formula (300,000 m/s / 0.000000383 m/sec^2) we get 2483.8 years. It takes two and a half millennia to accelerate to a measly 1% of lightspeed.
It is indeed a very slow form of acceleration at this point. Here is to hoping the many minds we have will improve on the concept over the next two decades, we must remember this technology is still in its infancy, actually we aren't even 100% sure it works as described yet.
Indeed. I'd like to also add, in case it gets brought up, that there is a reaction drive that converts energy to thrust -- and it's called a photon drive. The problem with using straight energy for thrust is that it takes an absolutely ludicrous amount of power to generate even small amounts of thrust.
Wouldn't this be good for a deep space probe though, since it can just accelerate forever (even if the acceleration is slow) and eventually attain huge speeds since it doesn't ever run out of fuel?
Except the acceleration is too low for even that, and it'd likely end up more efficient to use even something like an antimatter pion drive. Hell, you might be able to even get more thrust from something as low-acceleration as a plasma sail and simply "sailing" around stars en route to your destination, making use of gravity assists. It largely depends on how much power one's willing to expend on the photon drive.
For a quick calculation, let's assume we have a turbine from the largest dam in the world, the Three Gorges Dam. They weigh 6,000,000 kgs and output 700 MWs each. Just from those stats (and neglecting pesky stats like where the fuel is coming from or the engine weight), it would output 2.3 newtons of thrust for a total acceleration of (2.3N = 6,000,000 kgs * x m/sec^2) 0.000000383 m/sec^2, or 0.000000039 Gs. To put that into perspective, using the formula (300,000 m/s / 0.000000383 m/sec^2) we get 2483.8 years. It takes two and a half millennia to accelerate to a measly 1% of lightspeed.
It is indeed a very slow form of acceleration at this point. Here is to hoping the many minds we have will improve on the concept over the next two decades, we must remember this technology is still in its infancy, actually we aren't even 100% sure it works as described yet.