I get it that it requires yet-impossible materials to build a space elevator that goes all the way to space, but what if we instead build one that only extends high enough to clear the thickest layers of atmosphere, so rockets could be launched from there for massive fuel savings?
Space Elevator
331–340 of 414 posts
Re: Space Elevator
#332Earlier quoted context omitted.
Space elevator was the perfect application for carbon nanotubes according my professor few decades ago. I wish humanity could unite for such project and enter space exploration phase. But I feel it will stay sci-fi forever.
Thing is, you're going to invest massive amounts of R&D in something that might be impossible, when you could invest in actually building stuff in space so you only need to shoot humans out there.
Instead of massive amounts of R&D, why not small amounts for the next 100 years? Seems like this is something a tech bro could bequeath to humanity, Nobel style. A $250 million fund that pay out $10 million per year in grants. And maybe some larger chunks when the board of directors sees a good opportunity to do larger scale trials.
Re: Space Elevator
#333the space elevator has to go a LOT higher than that. also, the landing gear is down on the reentering shuttle. The big thing people don't get is that orbit is about sideways speed not altitude and this does nothing to address it. I don't get the hype for this, it's cute but not much at all.
Re: Space Elevator
#334"Temperatures in the thermosphere can reach 2,500°C, but molecules are so far apart that you wouldn't even feel it."
I don't have a science background. But how does this work? If you can't feel it, how would you measure it?
Space boggles my mind I love it!
Re: Space Elevator
#335Cool, I had no idea bumblebees can fly that high.
Re: Space Elevator
#336I found this strangely emotionally affecting. Probably on account of the music, but I was really struck the vastness and loneliness as the elevator went higher and higher (and we're still nowhere close to the moon).
Re: Space Elevator
#337I get it that it requires yet-impossible materials to build a space elevator that goes all the way to space, but what if we instead build one that only extends high enough to clear the thickest layers of atmosphere, so rockets could be launched from there for massive fuel savings?
We can't practically build a tower that tall. A space elevator would work by hanging off a counterweight (possibly more space elevator cable) which means it needs to go past geostationary orbit.
Re: Space Elevator
#338Earlier quoted context omitted.
A space elevator doesnt just take you to the karman line (like in the OP website), to get to orbit, you'd need to get up to geostationary height. That's 22,000 miles. What's the best way to pull yourself directly vertical along a cable for 22,000 miles? What's the best way to descend 22,000 miles quickly, but also with a braking mechanism that isn't going to require a heat shield? Some sort of slow cable car going at…
Unless we're using it for humans the transit time isn't that big a deal; "last mile" orbital transfer times are often measured in days anyway. That "last mile" bit is going to entail independent propulsion anyway. Getting to the altitude if the ISS is a mere 10 hour trip at a sedately 40kph which isn't unpleasant even for humans, but the ISS orbits at nearly 29000kph (as will you if you let go of the space elevator a…
> as will you if you let go of the space elevator at that altitude)
Doesn't the teather have a constant (24 hour) rotational period at every elevation? That is significantly slower than the ISS
Re: Space Elevator
#339Earlier quoted context omitted.
> it's just hard to go up Going up is the comparatively easy part, it's not exactly rocket science. Going fast enough sideways so you stay up there is the tricky bit.
> Going fast enough sideways so you stay up there is the tricky bit. nah, thats the simple part. getting up there efficiently is the difficulty. once we're up, its just a matter of force over time to create a nice orbit. The faster you go, the more friction you face, and the more heat and vibration your equipment must endure. Going slower reduce friction and stress but use more energy just negating gravity. Slow rock…
The best way I’ve seen it described is that the first 9.8 m/s² of thrust only makes you hover in place. So the more g forces you generate the higher the efficiency of the engine - as long as thrust per kg of fuel doesn’t dip too far.
This all changes in outer space, where 0.01g is a valid propulsion mechanism for long duration missions.
Re: Space Elevator
#340Earlier quoted context omitted.
> it's just hard to go up Going up is the comparatively easy part, it's not exactly rocket science. Going fast enough sideways so you stay up there is the tricky bit.
This is where Douglas Adams was right, of course: > There is an art, it says, or rather, a knack to flying. The knack lies in learning how to throw yourself at the ground and miss. You're not going sideways - you're actively falling continuously, but somehow missing the ground for the entire length of your orbit.
Missing involves going sideways.