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Comment: Re:Someone doesn't understand basic relativity (Score 1) 79

The balancing act is almost exactly the same at the last moment of forward flight as it is at the first moment of retro burn, just in a different direction.

Aerodynamics matter very little at high altitude. They matter some at lower altitude, but I doubt they make much difference when the engine is burning.

Comment: Re:Wildly premature question (Score 1) 79

by Bruce Perens (#48620117) Attached to: SpaceX To Attempt Falcon 9 Landing On Autonomous Spaceport Drone Ship

If we look at jet aircraft, wear depends on the airframe and the engines, and the airframe seems to be the number of pressurize/depressurize cycles as well as the running hours. Engines get swapped out routinely but when the airframe has enough stress it's time to retire the aircraft lest it suffer catastrophic failure. Rockets are different in scale (much greater stresses) but we can expect the failure points due to age to be those two, with the addition of one main rocket-specific failure point: cryogenic tanks.

How long each will be reliable can be established using ground-based environmental testing. Nobody has the numbers for Falcon 9R yet.

Weight vs. reusable life will become a design decision in rocket design.

Comment: Re:Someone doesn't understand basic relativity (Score 1) 79

The mass is less, and presumably easier to control, but yes, that is a difference.

The relative speeds are the same. Launch starts at 0 and increases to 1300. Landing starts at 1300 and ends at 0.

Actually, that is a small difference. Launch starts at 0, but landing ends at 2 m/s, leaving shock absorbers to reduce it to the final 0.

Comment: Someone doesn't understand basic relativity (Score -1) 79

And I don't mean the speed of light kind.

At 14 stories tall and traveling upwards of 1300 m/s (nearly 1 mi/s), stabilizing the Falcon 9 first stage for reentry is like trying to balance a rubber broomstick on your hand in the middle of a wind storm.

EXACTLY the same as takeoff. NO difference.

Comment: If... (Score 1) 103

by jd (#48546713) Attached to: Neglecting the Lessons of Cypherpunk History

You are vulnerable to Social Engineering (and almost everyone is), no security of any kind will ever work. Become a Scottish crofter, it's your only hope of a life.

You are a private individual, see all XKCD coverage. Same remedy.

You are Sony, abandon hope now. You wouldn't even make it as a crofter.

You are anyone else, encryption is not enough. You want segmentation, active NIDS, proxies and firewalls at the gateways, HIDS on the machines, role-based access controls, host-to-host IPSec, security labels on packets, total removal of all vulnerable protocols, disk encryption, strong authentication and Neuromancer's Black Ice. A platoon of extreme freediving Ninja with enhanced magnetic sensors in their eyeballs would help, too.

Comment: Re: Diversity is good, especially in SciFi (Score 1) 367

by jd (#48545413) Attached to: Overly Familiar Sci-Fi

Science fiction isn't fiction that has elements that aren't science but might appeal to geeks who like science.

Science fiction isn't science fantasy.

Science fiction isn't pure fantasy with stuff science geeks like.

Science fiction isn't biologically improbable females fulfilling spotty teen fantasies.

Science fiction is science that is fictional. Very different animal and naturally restrictive.

That's life. Or will be.

Comment: Re: you're doing it wrong (Score 0) 367

by jd (#48545395) Attached to: Overly Familiar Sci-Fi

Absolutely wrong on all accounts.

People are the least important part of a story, they exist solely to represent something. What they represent is almost never another person. In fact, it is never another person.

Science fiction is about the universe, about meaning, about the nature of reality. There are perfectly good science fiction stories that don't include people, or indeed any living thing. And that is fine.

Stories that are people-centric are no more science fiction than vampire stories are history, or Microsoft manuals are about learning.

This isn't up for discussion, it is the way the ontology is. Don't like it? Fine, don't call your crap science fiction. It's very simple.

Comment: Re:TIE-Fighters flying in Atmosphere?!?!?!?! (Score 1) 390

by jd (#48483535) Attached to: First Star War Episode 7 Trailer Released

I think it was the second of the unofficial Han Solo novels during the time of the Original Trilogy that first had TIE Fighters in the atmosphere. So you're absolutely right that they're impossible, but it's "legitimate" extended canon. (Which is why I don't consider anything after the first movie "canon" at all.)

An authority is a person who can tell you more about something than you really care to know.

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