Space Elevator
neal.fun
neal.fun
1. Some birds go really high into the sky. Not sure how they evolved to tolerate such a hostile environment. But it seems that Duck-like birds are able to handle very high altitude.
2. There are lots of cool spaceships that man has made. But it seems most of these were made in the 1950-1990 era. It's a shame that we are no longer doing that.
* The Falcon 9, the first partially reusable spaceship that actually costs less than not re-using anything
* Terran R - a fully reusable space ship in the works by relativity space
* RocketLab Electron - an active rocket that is unique in its use of electric turbo pumps, 3d printed engines, and advanced composites use
* RocketLab Neutron - in the works, a larger rocket with the aim to be partially re-usable ala Falcon 9 but with a cheaper expendable 2nd stage and simpler design
* SpaceX Starship - in the works, (test flight today!) a large heavy lift vehicle with the aim to be fully reusable
* Blue Origin - working on a ship similar to starship
there are others!
Stranger things have happened though I suppose.
We don't really know that. This _appears_ to be the case but the accounting is strange. We would probably get better numbers if the company was publicly traded.
I really like the RocketLab designs.
Where's the funding for Skylon? Some US company with deeper pockets should license the design (the heat exchangers are incredible)
Another possibility is: Space is too hard. So instead the focus is to analyze (ie: James Webb) instead of sending a human there.
Seems to be a good chunk of (educated) conjecture.
https://journeynorth.org/monarchs/resources/gallery/gallery-...
"We" have built a lot of spaceships since then but they simply went higher up than "just" 100km, so don't show up in the OP.
Wikipedia has an article that touches on this here: https://en.wikipedia.org/wiki/Space_elevator_safety
Maybe for cargo the 20 days are not really important
80% of the energy in a rocket goes to adding sideways motion.
An elevator upto GEO adds enough energy (taken from the earths rotational energy) to your payload to get it into orbit. If you let go lower down you need to add sideways velocity.
In LEO you on an elevator would be travelling about 1,400mph and need to get to 18,000 to get into orbit. Sure there’s no atmosphere to work against but it’s still a lot of fuel to use in a rocket.
That's a pretty significant speed already and it helps that you are already in space. See how tiny a Pegasus rocket is, and that one is launched from aircraft, slower, and nowhere near as high as what we are discussing.
https://www.northropgrumman.com/space/pegasus-rocket/
Getting to 100km from ground requires beefy first (even second) stages because you need to accelerate further stages plus the fuel, inside the atmosphere. We can basically pretend we are starting at the second or third stages. It now up to the rocket equation.
So, to recap, there's already 1400mph of sideways motion, at a negligible air resistance, 100 to 200km up with vacuum optimized nozzles. It is a massive win.
The question is if we could hoist what are still relatively heavy payloads.
(Haven’t done the exact maths, I suspect the delta is even closer than 300moh)
I have not researched this at all, so I'm not doubting you, but doesn't most of the energy go into accelerating the remaining fuel? So, by the rocket equation, shouldn't you be way ahead of the game by starting at the edge of space?
There is an excellent What-if on this: https://web.archive.org/web/20230211050159/https://what-if.x...
Rockets will have abandoned solid fuel boosters long before then.
Satellites and space stations are always in free fall. The thing that keeps them in "space" is the velocity with which they were originally launched to orbit the Earth as centripetal force becomes the weight of the satellite, which slows down such falling process. Seeing it with cold eyes, they employ all the energy at a first for to lift the weight of that falling object.
If a geostationary satellite has to stay over the same region of the planet, it has to be sent much much far away, until its orbital velocity become synchronized with the Earth's rotation. And even like that, keeps being in free fall due Earth's gravity.
I mean, what we see in cartoons or sci-movies about to send a rocket absolutely vertical and cut engines, or a spaceship joining over a planet and conserve the same orbital position, could be done only with anti-gravitational engines. A small liquid fuel could not maintain them in place.
It would be more clear to say that what keeps them in space is that they're moving sideways so fast.
Velocity, not acceleration, is the right term here.
To name a few low-hanging fruit:
The research done to make it possible, would definitely advance several fields.
The ability to access photons from outside of the atmosphere should vastly improve how much energy we could capture from the sun. Pair this with transparent solar tech designed to pass through the wavelengths that are useful to plants, and we can factory farm crops in space using fully automated systems. This could also lead to exploration of engineered crops that can withstand (and potentially absorb radiation), that may serve as a biological wall for the humans.
Obviously, it would be a given that asteroid mining would become vastly more simplified, and autonomous robotic space construction and perhaps even asteroid mining would become a fantastic way to profit from it (or/and dilute the value of existing rare earth minerals/metals).
Obviously, this would also make intra-solar travel orders of magnitudes cheaper.
Maintaining and cleaning up space debris would become substantially simpler.
Building planetary defense mechanisms (against extinction level events) would become more feasible if we have this in place.
There are obviously an enormous number of things that could go wrong with a project like this, but given a CERN or Manhattan Project level of funding and cooperation, I think we could build this in a couple decades.
This is the kind of future I would want to be a part of. The cost estimate I think was somewhere in the trillions, but even so, the potential benefits are so vast that it just doesn't make sense not to do it, right?
In case you don't want to google the wiki page: https://en.wikipedia.org/wiki/Orbital_ring
Don't even take my word for it. Go question ChatGPT about it.
Here's the thing with an ORS: why have one 350km-high ORS, when you can build a stack of ~60 of them out to geosynch? Such a stack is an ORS-Jacob's-ladder, and is a compromise between a full Clarke-style space-elevator and reality.
I'm sure you could build it in a way that it would break apart into lots of smaller pieces, but even then it seems like it could be dangerous.
Plus accidents are more likely than you think. A rocket just exploded this morning, and read up on rates of railroad or shipping screwups. A train full of apples and pallets of kleenex going over ain't a big deal but the same containers falling out of the sky will certainly cause more damage.
Also it would not be an "Ultimate target" for "terrorists". Terrorists are violent political activists, not super villains that want to destroy the world. I doubt, for example, that the new-IRA would get a united Ireland by destroying orbital infrastructure.
The most effective way for the new-IRA to unite Ireland would be to help the UK keep shooting itself in the foot, so that the Northern Ireland citizens get sick of regular Ireland being better off economically, and vote to join it.
You're forgetting religious extremists and countless suicide bombers.
You break a space elevator at the ground, it floats upwards.
You break it at 30,000 foot then everything above the break floats away upwards, everything below "crashes" down, at a relatively low terminal velocity and thus with pretty low amounts of energy.
An elevator isn't a tower, it's a rope handing from a counterweight in orbit which is kept taut by a centrifugal force. It's anchored at the ground to stop the rock floating away, but if you break that anchor everything above will swing away from Earth
If you have the ability to break the cable at say 100km above the ground, you have the ability to drop objects from that height anyway, don't have to deal with no-fly-zones, and can target somewhere not on the equator.
Want to cause chaos? Get a bunch of heavy dense cheap bits of metal, put them in a high altitude balloon, then drop them over a city. You'll cause more damage to the people on the ground than anything you could do to a space elevator (short of the financial impact of having to resplice it)
If you can damage the elevator at the counterweight end, then you have the ability to drop a "rod from god" and cause more damage that way.
I would like to see an analysis. 100’s of tons of string falling and accelerating the surrounding sheath of air (acts absolutely nothing like a meteorite). A good physics question!
Space elevators are inherently create a new safety risk as cutting them at geosynchronous orbit only takes compromising some security and building a modest bomb. Both of which are achievable by terrorist organizations.
PS: 911 didn’t happen because terrorists suddenly figured out how to build giant aircraft to douse buildings in tons of jet fuel they subverted an existing system that solved 99.9% of the technical problems. Thus by getting a few violent individuals on board with simple weapons simplified things to only needed to fly an aircraft that someone else built, got into the air, and filled with fuel.
It's negligible when it's that diffuse. Even if it didn't burn up, it's mostly lost to air resistance, with everything over a few hundred meters being limited to about terminal velocity.
And that size ring, is pretty useful.
Also, ring != elevator.
Probably still want to engineer it such that destruction is controlled rather than uncontrollable, but the biggest issue with it being destroyed would be no longer having it; the damage would be mostly within a meter or so of where it lands, which isn't great but it's also not devastating unless you happen to be that close.
Think a very long I-beam falling off a skyscraper during construction, not an asteroid.
whooper swan casually floats by
I just wish there was one way to switch all units. The temp. can be switched between F/C by tapping on it.
The height is metric and seems fixed and then stuff in text bubbles is again imperial (e.g. mph instead of kph).
Remember, there are only three countries that use imperial units; two third-world counties, and a global superpower.
Road distance is miles, running its metres. Except for the marathon. Beer is pints, my milk is litres but you can get pints. The lamb in the fridge for the weekend is 2.3kg, I’m 5’11 and way a little over 14 stone as I’m far, probably because of the 200g of Brie I am thinking about eating tonight. I was looking at a floor plan the other day, the room was 6.5m x 3.8m
We also haven't made the switch to metric time yet ;)
You'll find that it's stranger than known
Really made my day.
As soon as I see the domain neal.fun, it is a must click.
> Unlike the troposphere, the temperature in the stratosphere increases the higher you go.
It may not be as significant as the impact of an Earth-based one, but any propellant savings is a win.
The problem is: the benefit of a space elevator is bigger the deeper your gravity well is, but it's also much harder to impossible to make one there.
But I've also been wondering: wouldn't it be possible to have a tapering space elevator? Reduce the weight by making the parts that have to carry less weight thinner?
A steel cable would be 1mm thick at the bottom and several light years* thick at the top.
*hyperbole. Maybe.
A lightyear is around 10^19mm. Given that it's by area, a square lightyear is ~10^38mm^2. The cable is about 100 times thinner than it.
Amazing how high the F-104 Starfighter could fly, by the way.
Okay, haha, now that gives a nice perspective how far is the Moon.
Now I think the solution is to build an industrial base on the moon. The lunar factories and mines (mostly run by robots) will harvest the necessary material, do some initial refining, and then fling the products into space using mechanical techniques (something like SpinLaunch, or a giant catapult). Lifting off from the moon is far easier than getting off the Earth (think of that tiny lander that the Apollo astronauts used).
the space elevator.. it is a story of human progress .. it is something we will get to build one day
- 18,000 ft; 5,500 m: 20-30 min
- 22,000 ft; 6,700 m: 10 min
- 25,000 ft; 7,600 m: 3-5 min
- 28,000 ft; 8,550 m: 2.5-3 min
- 30,000 ft; 9,150 m: 1-2 min
- 35,000 ft; 10,650 m: 30-60 sec
- 40,000 ft; 12,200 m: 15-20 sec
- 43,000 ft; 13,100 m: 9-12 sec
- 50,000 ft; 15,250 m: 8-10 sec
Here's a demonstration of the effects of hypoxia and time of useful consciousness done in a hyperbaric chamber by SmarterEveryDay: https://www.youtube.com/watch?v=kUfF2MTnqAw
[1]: https://en.wikipedia.org/wiki/Time_of_useful_consciousness
Also, didn't realize how badass Monarch Butterflies are.
- butterfly can fly crazily high (3500m)
- You can find Pterodactyls and wild Yaks higher than a cessna
- a vulture can fly higher than a passenger plane (regular altitude)
How do the molecules reach that temperature?
Arthur C Clarke wrote a great story about space elevators called "The Fountains of Paradise".
Now everything is pretty mute and minimal (not saying its bad, I do this for my UX/UI too) so its nice to see this stuff!
It would not feel warm to you though, it would feel basically like space.
This is a poor analogy, but consider the difference between a single drop of water hitting your skin at high speed, versus a slow moving wave of water going over you. The drop has more energy, and if you just measured its 'speed' it would be higher than the wave.
EDIT: and curves.
Niggle: With a trackpad, you might need to scroll "down." I thought it wasn't working, for a few seconds, but that's a fairly common issue with trackpads and mobile interfaces. "Up" and "down" are kind of relative.
I loved this.
"...above this altitude your saliva and tears will boil if you don't have a pressure suit." :-$
Edit: Okay, depends on where you live and learn.
I see you can switch degrees from °F to °C, thanks.
Would be nice to have a switch from m to km, too.
iPhone SE 2016 - iOS 15.7.3
Anyone know the tech stack used to make these?
Insane. 17k meters.
Also there were many others which surprised me.
Am I missing something?
In other words, a functioning space elevator would be grand, epic and useful in ways that make the potential loss of some satellite orbits look like a very minor detail. At least that's my take. Too bad about the materials science not doing its part, huh. :)
Horseless carriages in this comparison are rockets.
EDIT Also, this thing stops at the Karman line. That's not a viable space elevator. Pretty widget, though.
There are plenty of zero-fuel launch possibilities and a few very high-ISP ones. On the long term one of them is inevitable, but it's pushing it a bit to claim that it will be the space elevator.
And the very high ISP options are all on the same category in that they can save you more fuel than the zero fuel ones, but only if you want enough delta-v.
None of those are viable today, but most are in a "we can make all parts, but it's a fucking big machine that we can't assemble", while the elevator is still missing parts.
2) It's been around long enough to have made it into mainstream culture, especially via big-budget Hollywood movies.
3) The name is straightforward and approachable to laypeople. An elevator to space nicely obscures issues like its mind-boggling size, duration of transit, and even "reach space" vs "achieve orbit."
4) Picturing the structure fixed over a point on Earth seemingly sidesteps sovereign territory issues and international cooperation, further simplifying the conversation.
The Space Elevator is a gateway to megastructures more than a gateway to space.
Is that sort of collision inevitable or can you have parallel orbits that don't collide? I'm ignorant and this is the first I'm hearing of this issue. Last I heard the material science part was the heartbreaker.
(when I was a kid in the 60s/70s, the cool thing was geostationary satellites)
Is there any prospect at all of a material strong enough to handle this?