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We need a better way to get to space

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Re: We need a better way to get to space

#21

Post by rthomas6 »

nickff wrote: post #8
rikkus wrote: post #6

20 years ago, I remember dreaming up a train pulling a cable with a glider at the far end. I'm sure there are many technical issues with this approach, possibly including the cable needing to be incredibly strong, light and flexible. Please tell me it would work, though, as I still enjoy the mental image.

Reaching orbit is mostly an issue of velocity, not altitude. This is why balloons can get very high, above of almost all earth's atmosphere, while being far from orbit. Rockets spend most of their ascent traveling nearly horizontal to the ground (they only go straight up at the beginning to get out of the densest part of the atmosphere).

What about geostationary orbit wrt balloons? Do the balloons slow down horizontally a lot during the ascent? If not, what if we floated a rocket up most of the way and let the rocket do the rest?

Re: We need a better way to get to space

#23

Post by rm_-rf_slash »

I'm no rocket scientist but I could imagine rockets having a place in regular space travel. Lets assume that we can harness solar power efficiently and safely store the extra energy in hydrogen and oxygen gas. Then let's say that we could construct sturdy and modular components that can be disassembled and re-assembled at some kind of orbital station, so that the boosters that take people into orbit for whatever reason could be rebuilt in orbit to carry a load of asteroid-mined metals back to the surface.

Again, I don't know any of the mechanics or physics, but if energy was abundant and parts could be reused, would rockets really be all that bad?

Re: We need a better way to get to space

#24

Post by anon8764 »

grogenaut wrote: post #18
anon8764 wrote: post #12

Earlier quoted context omitted.

Perhaps technology has advanced too fast for the "culture". Perhaps we should design our intentions before we build the tech, and not the other way around. Look at NASA for inspiration on design and forethought.

The problem with this is you're designing based on your current world view and assumptions. When does this type of planning ever work and actually stand up to 20 years of history? 40? 100? In the 50's the us was DESIGNED around the car and suburbs. That worked well.

My logic is based on numbers. Earth Population, Imaginary lines in the sand, War over money. These are not signs of intelligence, especially when they have only 1 planet to survive on that gets more populated every day with little regard to long-term resource management, although I am proud of the Svalbard Global Seed Vault. :)

This type of planning worked for Voyager (NASA/JPL).

fyi: cars suck. Dirty, inefficient, and it follows the same logic of giving every person in a 200 person hotel an individual elevator. It makes no sense, when you can instead design cities and transportation to be like the site I linked above (www.et3.com).

It's their choice though, if they want faster horses instead of cars, so be it. If they want faster cars instead of et3, so be it.

They prop and fall on their own sword I suppose.

Re: We need a better way to get to space

#25

Post by jcfrei »

drewg123 wrote: post #22

I was hoping the article would talk about space elevators, and not space planes. I'm eagerly awaiting materials science and geo-politics to mature enough to allow the construction of space elevators. https://en.wikipedia.org/wiki/Space_elevator

I don't really see the benefits of space elevators, to be honest. At an altitude of 100km the gravity is still virtually the same. And you still need a huge amount of fuel in order to put your rocket/plane into orbit. Unless you build an elevator with a height of 42'164km (geostationary orbit) - but that seems unrealistic to me.

Re: We need a better way to get to space

#26

Post by anon8764 »

reitanqild wrote: post #19
anon8764 wrote: post #7

www.et3.com gradually leading up to the top of everest, jettisoning the capsule (6,500 km/h (4,000 mph)) to break out of the atmosphere. I have not done the math, physics, etc on this, but it's an interesting idea worth exploring. But that said, do we really belong in space when we cannot care for our own? Wouldn't that be akin to giving sugar to ants? only multiplying suffering and cruelty exponentially in space? Pe…

(anon8764 was downvoted when I wrote this.) I disagree but still upvoted this to get it to 0. I find the tought interesting but wrong. It seems more suffering is caused by various misguided attempts at refactoring culture etc and less by technology. National socialism and communism are two widely known attempts at refactoring culture that has created more misery than all technological advances combined so far.

I prefer a Resource-based Economy (rather than the failed money-strived attempts) that has a central hub for resource-distribution to all humans based on global reserves to raise the standard of living for all instead of a select few which every monetary system has ultimately created.

This would make an interesting topic to discuss how to design this system with our current tech, but that's another thread altogether.

Re: We need a better way to get to space

#27

Post by ZenoArrow »

jcfrei wrote: post #25
drewg123 wrote: post #22

I was hoping the article would talk about space elevators, and not space planes. I'm eagerly awaiting materials science and geo-politics to mature enough to allow the construction of space elevators. https://en.wikipedia.org/wiki/Space_elevator

I don't really see the benefits of space elevators, to be honest. At an altitude of 100km the gravity is still virtually the same. And you still need a huge amount of fuel in order to put your rocket/plane into orbit. Unless you build an elevator with a height of 42'164km (geostationary orbit) - but that seems unrealistic to me.

> "I don't really see the benefits of space elevators, to be honest. At an altitude of 100km the gravity is still virtually the same."

You would have made the first 100km of the journey more fuel efficient, is that not a good enough reason?

Re: We need a better way to get to space

#28

Post by mynegation »

rthomas6 wrote: post #21
nickff wrote: post #8

Earlier quoted context omitted.

Reaching orbit is mostly an issue of velocity, not altitude. This is why balloons can get very high, above of almost all earth's atmosphere, while being far from orbit. Rockets spend most of their ascent traveling nearly horizontal to the ground (they only go straight up at the beginning to get out of the densest part of the atmosphere).

What about geostationary orbit wrt balloons? Do the balloons slow down horizontally a lot during the ascent? If not, what if we floated a rocket up most of the way and let the rocket do the rest?

Balloons float because dense air in the lower parts of atmosphere pushes them up with buoyant force. They lose the ability to float way before they would reach LEO, let alone GEO.

Re: We need a better way to get to space

#29

Post by rakoo »

chris_va wrote: post #20
iwwr wrote: post #9

Earlier quoted context omitted.

Light-gas guns may be a good contender while railguns are sorted out. https://en.wikipedia.org/wiki/Light-gas_gun

Surprisingly, I actually did a fair bit of research into this field. Both rail guns and light gas guns cap out at around 6km/s, and you really want 8km/s (more actually, for hypersonic drag loss) for this to be economical. Otherwise you need to launch a large enough rocket to make up the 2km/s difference, and you stuck solving the rocket equation again. Except you've subjected your rocket to 1000g, and the odds of it…

> and you stuck solving the rocket equation again

Yes, but only for 2km/s, so there's that. Also this system can be used on other bodies such as Mars and the Moon.

But yeah, I'm more worried about the 1000g than anything.

Re: We need a better way to get to space

#30

Post by thedufer »

jcfrei wrote: post #25
drewg123 wrote: post #22

I was hoping the article would talk about space elevators, and not space planes. I'm eagerly awaiting materials science and geo-politics to mature enough to allow the construction of space elevators. https://en.wikipedia.org/wiki/Space_elevator

I don't really see the benefits of space elevators, to be honest. At an altitude of 100km the gravity is still virtually the same. And you still need a huge amount of fuel in order to put your rocket/plane into orbit. Unless you build an elevator with a height of 42'164km (geostationary orbit) - but that seems unrealistic to me.

> Unless you build an elevator with a height of 42'164km (geostationary orbit) - but that seems unrealistic to me.

Actually, much of the point is to build one that is significantly taller than that. The idea is that, if the center of mass sits at geostationary orbit, the elevator doesn't actually have to hold itself up. Centripetal forces do the heavy lifting. Try the wikipedia link posted by gp - the first thing you'll see is a very clear diagram.

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