Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Nuclear Conversion for Starship

toughsf.blogspot.com

Post reply on HN
Print view View original

141–150 of 155 posts

Re: Nuclear Conversion for Starship

#141

Post by LargoLasskhyfv »

perihelions wrote: post #124
bluescrn wrote: post #80

Nuclear doesn't work with Elon's approach to development. You can't blow up multiple nuclear rockets within the atmosphere just to learn what needs fixing for the next attempt. Then again, it's looking like the whole 'fail fast' approach is over anyway, with Starship grounded by red tape. A full-stack Starship failure is seemingly too big/dramatic/risky to get away with doing repeatedly, especially admidst the politi…

- "You can't blow up multiple nuclear rockets within the atmosphere just to learn what needs fixing for the next attempt." Sure you can. Russia has blown up multiple experimental nuclear-powered cruise missiles in the last few years [0,1]. It's a political question of tradeoffs, of how much you value technological progress on a particular front. America hasn't blown up any atmospheric nuclear reactors in this century…

> America is also unlikely to learn how to build aerospace nuclear reactors in this century.

Why should it? It already knows. Since last century:

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

In a place called 'Jackass Flats', of all things...(Giggle)

Edit: Or take the https://en.wikipedia.org/wiki/NERVA mentioned here by credit_guy: https://news.ycombinator.com/item?id=38136383

Same place, name is program :-)

Re: Nuclear Conversion for Starship

#142

Post by LargoLasskhyfv »

fsloth wrote: post #59
maxcan wrote: post #9

AFAIK, the only nuclear rocket that makes sense is landing a reactor on an icy comet and using it to shoot super heated steam wherever you want thrust. #seveneves

Project orion was super cool and I warmly recommend the book by similar name by George Dyson (son of Freeman Dyson!) who did a tremendous job of putting everything back together as well as humanly possible for an ops with very top secret components. Nukes can totally function as the energy for rocket’s impulse. Very small and very directed nukes. The directed explosion plasma wave hits a pusher plate, where very spec…

Yah, but that would also enable https://en.wikipedia.org/wiki/Casaba-Howitzer , wouldn't it?

Re: Nuclear Conversion for Starship

#143

Post by wkat4242 »

bluescrn wrote: post #80

Nuclear doesn't work with Elon's approach to development. You can't blow up multiple nuclear rockets within the atmosphere just to learn what needs fixing for the next attempt. Then again, it's looking like the whole 'fail fast' approach is over anyway, with Starship grounded by red tape. A full-stack Starship failure is seemingly too big/dramatic/risky to get away with doing repeatedly, especially admidst the politi…

Starship is planning to launch soon according to ars technica, it was also posted to hacker news a few hours ago. So not too bad considering the red tape and damage to the launch pad.

Re: Nuclear Conversion for Starship

#144

Post by orost »

adrianN wrote: post #140
rockemsockem wrote: post #128

Earlier quoted context omitted.

Nuclear rockets are good in space, not in atmosphere and they aren't radioactive until you turn them on. You test in space. Also that isn't "Elon's approach to development" that's just how everything good has ever been made. Also if you plan to fail then you usually wind up failing more safely than if you don't plan to fail.

If they blow up while being transported to space they usually are radioactive too.

A reactor that has never been turned on isn't a significant radiation hazard. It's the fission products that are hazardous, not the fuel, if it's never gone critical there are no fission products yet.

Re: Nuclear Conversion for Starship

#145

Post by fsloth »

LargoLasskhyfv wrote: post #142
fsloth wrote: post #59

Earlier quoted context omitted.

Project orion was super cool and I warmly recommend the book by similar name by George Dyson (son of Freeman Dyson!) who did a tremendous job of putting everything back together as well as humanly possible for an ops with very top secret components. Nukes can totally function as the energy for rocket’s impulse. Very small and very directed nukes. The directed explosion plasma wave hits a pusher plate, where very spec…

Yah, but that would also enable https://en.wikipedia.org/wiki/Casaba-Howitzer , wouldn't it?

In the interviews some of the team members were concerned with proliferation of shaped-charge mini-nukes. IMO that's not a good reason not to do anything but not an expert.

Re: Nuclear Conversion for Starship

#146

Post by GordonS »

simonh wrote: post #64
Skunkleton wrote: post #41

Earlier quoted context omitted.

I make no claims about my reading comprehension. That last bit seemed too narrow to me. Once you have all the bits in orbit, shielding doesn’t seem too onerous. Is the claim that even space-space shielding + reactor is too heavy to be worth the advantage of the nuclear drive?

In space if you’re careful you only need a plate of shielding between the drive and the crew/cargo section.

Isn't radiation from cosmic rays going to require very heavy shielding?

Re: Nuclear Conversion for Starship

#147

Post by simonh »

GordonS wrote: post #146
simonh wrote: post #64

Earlier quoted context omitted.

In space if you’re careful you only need a plate of shielding between the drive and the crew/cargo section.

Isn't radiation from cosmic rays going to require very heavy shielding?

Sure, but that's got nothing to do with any additional requirement due to your propulstion system.

Re: Nuclear Conversion for Starship

#148

Post by tim333 »

bluescrn wrote: post #80

Nuclear doesn't work with Elon's approach to development. You can't blow up multiple nuclear rockets within the atmosphere just to learn what needs fixing for the next attempt. Then again, it's looking like the whole 'fail fast' approach is over anyway, with Starship grounded by red tape. A full-stack Starship failure is seemingly too big/dramatic/risky to get away with doing repeatedly, especially admidst the politi…

Assuming Elon gets Starship working reliably, which will probably happen, you could use it to lift a nuclear rocket to orbit. You could then fire the nuclear bit up away from the earth and use it to shuttle around the solar system.

Re: Nuclear Conversion for Starship

#149

Post by marcosdumay »

idlewords wrote: post #30
marcosdumay wrote: post #22

Earlier quoted context omitted.

Yes, but with very little long-lived decaying material that you could carry inside a survivable habitat.

Most nuclear spaceship designs have a long stick with the reactor at one end and the crew on the other, and some kind of shielding in between. Since you only need to shield a cone, it can be quite effective.

Yes, but none of that changes the fact that when we talk about fission rockets, we have to think about nuclear safety on top of everything else. (All of your comment is thinking about nuclear safety.)

And if we use them inside of a planet's magnetosphere, we have to think about environmental contamination too.

Re: Nuclear Conversion for Starship

#150

Post by adrianN »

orost wrote: post #144
adrianN wrote: post #140

Earlier quoted context omitted.

If they blow up while being transported to space they usually are radioactive too.

A reactor that has never been turned on isn't a significant radiation hazard. It's the fission products that are hazardous, not the fuel, if it's never gone critical there are no fission products yet.

It’sa sufficiently big radiation hazard that I wouldn’t want to be under it.
Post reply on HN