A tall tower could double payload mass to orbit

Transcript

Transcribed by machine (Whisper) from the episode’s audio, so a word may be off here and there.

1. 1:14:15

   feel like? Yeah. We looked at both of those. There's a, is it, um, well, uh, we're really about to go down a deep rabbit hole here, but, but there's a Ramjet accelerator that was developed at the university of Washington. That sounds like what you're, it's close to the long shot. talking about that and then um the uh um the the the centrifuge the centrifuge thing existed back then um under the name of slingatron uh but it was the same idea it's a spiral okay thing it's a big table that goes like this and you have a you have a spiral passage in it that, um, and it, it's a big gun basically. It's all big gun systems have got, um, problems that you're obviously aware of around, you know, what happens when you meet the atmosphere, you know, and that kind of thing. But, um, the, um, uh, I mean, as a kind of almost tongue in cheek thing,

2. 1:15:22

   I looked at gigantic steel bull whips, uh, which is still a topic I'm obsessed with. I've got five substack posts about about that kind of technology now um but um the the one that um that i i still think somebody ought to build is the tall tower okay so this came out of a paper by jeff landis um that um uh where he he went through and and enumerated all of the advantages that you would be able to benefit from by launching from the top of a tower.

3. 1:16:00

   And some of them are kind of non-obvious, like, well, if you know rocket engines, you know that one that's designed to operate in vacuum has a big bell, and it's more efficient. So you'd be able to do that. Some really odd things like you have to build the rocket so it won't destroy itself with its own noise. and it's not as noisy up there. You have to build it so it won't buckle at max Q. Up there, max Q is going to be a lot lower, and so you have to put less weight into structural strength of the airframe.

4. 1:16:48

   So when you add all those things up and factor those into the rocket equation, you know, an exponential equation, It turns out that, at least according to Landis' calculations back then, for a given kind of rocket configuration, you could get twice as much mass into LEO. Okay. I don't want to – no, sorry. I didn't mean to cut you off. Well, no, I can – I mean, okay. So then, I mean, SpaceX is clearly – they've gotten cadence way up for people who aren't space nerds.

5. 1:17:24

   Yeah. governments were super lucky to do 12 launches a year spacex is going almost every two days they've got reuse down they we've gone from roughly 2500 satellites in space now to about 15 000 almost the vast majority of that is overnight and driven by by starlink the starship is coming yep so you're talking mass to orbit i mean a giant leap forward on that but so and you've already said spacex is impressive but are you dissatisfied because you still want these far more like the starship the starship scratcher itch or do you still want more well yeah i mean um so the um the question that was before us you know at the beginning of blue origin was um could you uh is are there optimizations that you can apply to chemical rockets that would radically transform the economics of space launch um so it turns out the answer is yes uh that was not totally obvious back then um you know it was

6. 1:18:38

   kind of felt that if you look at you know uh let's say the space shuttle main engine you know it's a pretty amazing engine it's you know good the specific impulse of that engine is very impressive um so well that's not going to get a lot better you know the specific impulse is not going to get a lot better so um that's just a thermodynamic reality and so is there a way that you can um do something that's not all about that and so you know we looked at laser launch we looked at electromagnetic propulsion, you know, uh, and, um, uh, you know, all kinds of ideas, but the, um, um, uh, the, the, for me, the, uh, the, the attraction of the, the tall tower went beyond just, it's a good way to launch rockets. And there's this additional, um, factor of, uh, It would be really cool to have something that big, you know, and so it goes to the whole American dynamism, you know, why don't we build big things anymore kind of question.

7. 1:19:49

   And if it were built, I think it would be possible to monetize it in a whole bunch of additional ways beyond just. Just launching rockets from it. Yeah. Yeah. Well, I haven't seen anything that interesting, but China seems to be, it's got its own thoughts on reuse and things like that, which is kind of interesting.