Comments on: The Rocket Builder’s Handbook of the Twenty-First Century https://www.isegoria.net/2015/12/the-rocket-builders-handbook-of-the-twenty-first-century/ From the ancient Greek for equality in freedom of speech; an eclectic mix of thoughts, large and small Fri, 26 Jun 2026 21:34:46 +0000 hourly 1 http://wordpress.org/?v=3.6.1 By: Scipio Americanus https://www.isegoria.net/2015/12/the-rocket-builders-handbook-of-the-twenty-first-century/comment-page-1/#comment-2448730 Scipio Americanus Wed, 30 Dec 2015 20:24:23 +0000 http://www.isegoria.net/?p=39520#comment-2448730 “Our illustrious ancestors would probably build a hyperloop to the moon, which would confuse the heck out of Elon Musk”

https://en.wikipedia.org/wiki/Launch_loop

;-)

]]> By: Stephen Gustav https://www.isegoria.net/2015/12/the-rocket-builders-handbook-of-the-twenty-first-century/comment-page-1/#comment-2448652 Stephen Gustav Wed, 30 Dec 2015 13:22:33 +0000 http://www.isegoria.net/?p=39520#comment-2448652 Our illustrious ancestors would probably build a hyperloop to the moon, which would confuse the heck out of Elon Musk.

The real trick in rocketry is to decide exactly where you can economize. Deciding to use three COTS computers instead of one custom might save you 90% on cost but cost you x2 on weight. Deciding to use a cheaper (weaker, heavier) alloy might save you 90% on cost because it’s not only a cheaper material, it’s easier to work with. But it might fail catastrophically and your rocket goes ‘splodey.

Scipio answered my semi-rhetorical question on one of the other SpaceX posts. Rockets are hard, I am impressed with Musk and SpaceX’s achievement. And to a lesser extent, with Tesla.

Musk has made real what many have talked about for decades. And while many of the ideas have been there, it’s not like he walked into the rocket design store and picked the Falcon 9 design off the shelf and went back to his garage and built it. He and his team designed it, and made it work, and more – returned it to earth.

He has accepted government contracts, and government loans. That’s the environment we live in. Does that make him a rentseeker? He’s actually built a reusable rocket, the which Boeing, Lockheed, and countless government contractors have not despite half a century and probably trillions of dollars.

]]> By: Candide III https://www.isegoria.net/2015/12/the-rocket-builders-handbook-of-the-twenty-first-century/comment-page-1/#comment-2448608 Candide III Wed, 30 Dec 2015 10:44:44 +0000 http://www.isegoria.net/?p=39520#comment-2448608 I always reference this post on Hyperloop to counter the hype — and this update on costs.

]]> By: Scipio Americanus https://www.isegoria.net/2015/12/the-rocket-builders-handbook-of-the-twenty-first-century/comment-page-1/#comment-2448556 Scipio Americanus Wed, 30 Dec 2015 04:14:05 +0000 http://www.isegoria.net/?p=39520#comment-2448556 Admittedly, building the Hyperloop at a tenth the cost of high-speed rail isn’t as much of a feat as it sounds. Much of the cost of modern high-speed rail projects have nothing to do with engineering. I’m confident that the America of the ’50s gifted with the technology of today could build high-speed rail systems at maybe 1/20th the expense of their modern counterparts.

]]> By: Slovenian Guest https://www.isegoria.net/2015/12/the-rocket-builders-handbook-of-the-twenty-first-century/comment-page-1/#comment-2448501 Slovenian Guest Tue, 29 Dec 2015 22:05:17 +0000 http://www.isegoria.net/?p=39520#comment-2448501 And Just a Tinkerer (John Gardi) on How Elon Musk Can Build the Hyperloop for a Tenth the Cost of High-Speed Rail.

He and Musk are even Twitter buddies. La di da!

]]> By: Slovenian Guest https://www.isegoria.net/2015/12/the-rocket-builders-handbook-of-the-twenty-first-century/comment-page-1/#comment-2448496 Slovenian Guest Tue, 29 Dec 2015 21:43:49 +0000 http://www.isegoria.net/?p=39520#comment-2448496 Fun fact, from space.com:

“The Falcon 9 rocket costs about $16 million to build … but the cost of the propellant, which is mostly oxygen and a gas, is only about $200,000,” Musk said. “So that means that the potential cost reduction in the long term is probably in excess of a factor of a hundred.”

]]> By: Isegoria https://www.isegoria.net/2015/12/the-rocket-builders-handbook-of-the-twenty-first-century/comment-page-1/#comment-2448456 Isegoria Tue, 29 Dec 2015 16:12:40 +0000 http://www.isegoria.net/?p=39520#comment-2448456 Whoops! A typo ate the text of the link (“their own designs”). Fixed it.

]]> By: Stephen Gustav https://www.isegoria.net/2015/12/the-rocket-builders-handbook-of-the-twenty-first-century/comment-page-1/#comment-2448454 Stephen Gustav Tue, 29 Dec 2015 15:54:25 +0000 http://www.isegoria.net/?p=39520#comment-2448454 Link to the full article.

]]> By: Scipio Americanus https://www.isegoria.net/2015/12/the-rocket-builders-handbook-of-the-twenty-first-century/comment-page-1/#comment-2448425 Scipio Americanus Tue, 29 Dec 2015 14:11:34 +0000 http://www.isegoria.net/?p=39520#comment-2448425 Assuming a set Delta-V, payload fraction is the main area you can compromise. A few large-chambered engines specialized for the first-stage role are a more efficient use of mass than 9 small general-purpose ones, for instance. 3 redundant COTS computers are probably heavier than 1 radiation-hardened one. So on and so forth. The general rule for components and systems in rocketry is cheap = heavy.

]]> By: James James https://www.isegoria.net/2015/12/the-rocket-builders-handbook-of-the-twenty-first-century/comment-page-1/#comment-2448419 James James Tue, 29 Dec 2015 13:14:02 +0000 http://www.isegoria.net/?p=39520#comment-2448419 “they sacrificed some performance for a large reduction in cost”

I’m curious, in space rocketry, what other measure of performance is there other than cost?

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