3 ms·
He's using it to mean "high duty cycle over a time-period of minutes". That would be relevant if his criticism was "we don't know how to build lasers that use t
by jessriedel 3y ago
He's using it to mean "high duty cycle over a time-period of minutes". That would be relevant if his criticism was "we don't know how to build lasers that use that much power for that much time" (which is true, currently), but in fact his criticism was that it would require industrial power plants capable of outputting 100 GW (which is wrong). The big power draw of 100 GW over ~minute timescales is for the purposes of launching one probe. After that your power draw stops and you can recharge for as long as you want before the next probe launch. So it's not high duty cycle over timescales longer than hours or days or years.
- mlyle 3y agoThe thing is, it'd fundamentally different from lasers that have timescale of microseconds or less. He mentioned "capacitor banks." Launching 20 per day over a 10 minute span each is 200 minutes; you still need 12GW average over the day. And you need an insane amount of storage-- if 12% of the energy comes directly from the power plant, you need to store 53 terajoules, which is about 60,000 tonnes of lithium batteries per daily shot. (It's more than that, because you're power/discharge rate limited, and it's going to wear out that minimum amount of batteries quickly).
- jessriedel 3y ago> He mentioned "capacitor banks." No he didn't. I did. > Launching 20 per day over a 10 minute span each is 200 minutes; you still need 12GW average over the day. Where are you getting 20/day from? I didn't see it on this OP link or the Wikipedia page. I'd have guessed more like once a week, which is 100 MW. That's a reasonable size for a gas turbine power plant, which seems like an appropriate expenditure for a project like this. As a point of reference, the entire globe launches something to space every couple days on average.