Space Elevator(neal.fun)
neal.fun
Space Elevator
https://neal.fun/space-elevator/
215 comments
List of cool spaceships being worked on now or recently:
* 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!
* 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!
Sierra Nevada Corporation's Dream Chaser - a reusable lifting-body spaceplane, currently slated to fly to the ISS on top of the Vulcan rocket in December 2023
I had never heard of the Sierra Nevada Corp. and was confused when I thought about the beer company working on a rocket :)
Stranger things have happened though I suppose.
Stranger things have happened though I suppose.
In other beer space connections, Ball Aerospace and Ball containers who makes many beer cans were once the same company. Also made Ball canning jars.
What great idea didn't start as a sketch on a bar napkin?
Stoke Space is building a fully reusable rocket with a really unique second stage design.
https://youtu.be/VzqhZLgpiv0
https://youtu.be/VzqhZLgpiv0
> * The Falcon 9, the first partially reusable spaceship that actually costs less than not re-using anything
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)
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)
"Appears" or not, but their offered prices and especially the cadence of launching stuff to LEO are currently unmatched, AFAICT. They'd run out of money if they did not make profit on most launches
Question is, would they make more or less profit by making new rockets versus refurbishing the existing ones? By how much?
Go do some basic research? It's clearly much cheaper, ugh
SpinLaunch is pretty interesting too - throwing ships into space
https://www.spinlaunch.com/
I have to wonder what you mean we're no longer making cool spacecraft? The SpaceX starship is about to launch in an hour, it's very cool.
Watching the countdown now! T-00:28:12! Will be spectacular no matter what happens! Yes, I'm excited. Not sure how the parent comment has missed what SpaceX has been doing with Dragon, Starship, Starlink, and all the rockets! Amazing.
It exploded when trying to orient for the first stage separation. And it appeared to have 5 of the 33 engines out during the first stage flight. This launch gave me very "Don't Look Up" ending vibes.
Just the opposite. This is engineer-driven testing.
it's amazing how well this works for them. I think this is the main reason they can crank through development so fast. Wish this sort of development was more common.
The grand applause when they blew it up showed that it was a success.
Well to be faaaaaair, they were properly "primed" to applaud and call it a success, no matter what happened. But yeah, infinite money does that to you: you can operate in "fail fast" mode and obtain results you could not otherwise.
jackcviers3(2)
Yep. But you'd expect that we'd have more given how much technology has advanced and how bigger the economies are now. The recent progress is mostly due to Billionaires now.
Another possibility is: Space is too hard. So instead the focus is to analyze (ie: James Webb) instead of sending a human there.
Another possibility is: Space is too hard. So instead the focus is to analyze (ie: James Webb) instead of sending a human there.
The incentives for going to space are limited to more economic sensibility when you don't have a dick measuring contest going on between great powers.
Regarding 1, wikipedia about Rüppell's vulture (highest-flying bird) explains the adaptation:
"The birds have a specialized variant of the hemoglobin alphaD subunit; this protein has a great affinity for oxygen, which allows the species to absorb oxygen efficiently despite the low partial pressure in the upper troposphere. A Rüppell's vulture was confirmed to have been ingested by a jet engine of an airplane flying over Abidjan, Ivory Coast on 29 November 1973 at an altitude of 11,300 m (37,000 ft)."
https://en.wikipedia.org/wiki/R%C3%BCppell%27s_vulture
To your 2nd point, I'd venture an uneducated guess that the reason we were doing this was largely a part of the arms race between USA and USSR during that period.
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Swans and geese may not look like the greatest flyers when they're on the ground, but they're among the highest flying birds. But why? Is it their size and strength? Why do people have trouble breathing at that altitude, but birds don't?
I wonder how they estimated the flying altitude of pterodactyls.
https://www.npr.org/2010/11/16/131362653/peerless-pterosaur-...
Seems to be a good chunk of (educated) conjecture.
Seems to be a good chunk of (educated) conjecture.
Altitude of current birds x wing size ratio /s
I think there are still a lot of cool ones, but not as many sexy ones. Rocket planes like the X-15 were incredibly sexy, IMO, though in many ways not as cool and useful as current rockets.
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I was shocked to see a butterfly above the cloud level
Yes, and the bumblebee was up there pretty high too. You gotta wonder, what were they doing up there? Did they just get... lost? Just taking a nap in a thermal updraft?
It probably got above the clouds just the same way as the mountain goat did: By living on a high mountain.
I can't vouch for the quality of this site, but it says monarchs have been seen that high by aircraft.
https://journeynorth.org/monarchs/resources/gallery/gallery-...
https://journeynorth.org/monarchs/resources/gallery/gallery-...
3. The temperature gradient is weird, and doesn’t just get colder the higher you go.
> It's a shame that we are no longer doing that.
"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.
"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.
I think there's a lot of craft we just don't know about.
At 74km/h you would reach space (100km karman line) in an hour and a half but you would need to keep going for another 20 days at that speed reach geostationary orbit in order to not fall back to earth when you exit the space elevator.
Yeah, I wish this went on as far as an actual space elevator would, perhaps with extra visualizations of the heights of various orbits. The top would be slightly above geostationary orbit, since you would need the center of mass to be at the geostationary point in order to work.
Or more than slightly if you don't want to haul up a big counterweight but just use the cable itself as a counterweight. The Brad Edwards design proposes a total cable length of around 100,000 km. One very nice side effect of a long cable is that you can slingshot spacecraft from the far end up to ~Jupiter's orbit with zero propellant needed.
The other problem people seem to forget is radiation. The Van Allen belts expose people to a lot of radiation; normally it's not a problem, because either people stay under the belts (as in stations like the ISS which are at LEO), or for the few times humans went beyond LEO, to the Moon, they blasted through the belts very quickly and thus had negligible cumulative radiation exposure. But if you're sitting on a space elevator taking days to go through the VA belts, you'll probably get a fatal dose.
Wikipedia has an article that touches on this here: https://en.wikipedia.org/wiki/Space_elevator_safety
Wikipedia has an article that touches on this here: https://en.wikipedia.org/wiki/Space_elevator_safety
but do you need to reach geostationary? couldn't you just switch to a rocket at this stage? Maybe a small one to bridge the gap? I would have thought that the first kilometres are the ones where you have to invest the most work so if you just bridge them using the space elevator it would be still an improvement.
Maybe for cargo the 20 days are not really important
Maybe for cargo the 20 days are not really important
Getting to 100km or even 200km is easy. Staying there is hard.
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.
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.
> In LEO you on an elevator would be travelling about 1,400mph
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.
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.
Launching from the equator starts you at 1100mph though
(Haven’t done the exact maths, I suspect the delta is even closer than 300moh)
(Haven’t done the exact maths, I suspect the delta is even closer than 300moh)
> 80% of the energy in a rocket goes to adding sideways motion.
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?
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?
You still need to accelerate the fuel at that point. Free travel up to LEO doesn't buy you much.
There is an excellent What-if on this: https://web.archive.org/web/20230211050159/https://what-if.x...
There is an excellent What-if on this: https://web.archive.org/web/20230211050159/https://what-if.x...
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Can the speed be safely increased once you leave the atmosphere and there is no (appreciable) drag? With such a system in place, are there no other interesting places to stop along the way to geosync?
At that point gravity will act slower though, so it might be enough to take up a small liquid fuel craft too.
Rockets will have abandoned solid fuel boosters long before then.
Rockets will have abandoned solid fuel boosters long before then.
If you take a lift to a distance of 100 km and drop it, it will fall immediately reaching the ground in less than 10 minutes. Gravity remains strong.
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.
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.
Yeah, the thing people miss about the space station isn't that it's high up, it is that it is fast. It orbits the earth roughly every 90 minutes! It is literally faster then a speeding bullet.
> The thing that keeps them in "space" is the acceleration with which they were originally launched to orbit the Earth, which slows down such falling process.
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.
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.
I updated velocity. I also added centripetal force become the weight of the satellite for to try to explain it better.
I love this.
Reminds me of a thread I perused once re Orbital Ring Space elevator concept, and how it seems not only possible, but almost disgustingly cheap (in terms of the gains) with current technology. Not only would such an endeavor restore some aspect of pride to humanity, but the benefits are quite numerous.
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.
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.
The original paper for the ORS was engineered out of COTS from materials in the early 80s, designed to be built on a UK-friendly budget renting space from the US Space Shuttle program. With Space-X-like tech, it'd be hilariously cheap: especially with the new superconducting tape which didn't exist 40 years ago.
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.
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.
Never mind space elevators - we could build useful sky hooks right now (and Mars might be the best place to do it...) https://youtu.be/dqwpQarrDwk
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And so what about the downsides? The ultimate target for terrorists. If that comes down and it wraps itself around the Earth, it'll be devastating.
My understanding is that it would be under tension and orbiting at beyond escape velocity, such that if it got cut off, it would fly away from Earth. Still bad, but not catastrophically. Maybe we could even recover it.
But what happens to the tether it breaks away from? That won't stay up on its own.
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.
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.
That all assumes that it got loose at the base and not part way up within the atmosphere. If 9/11 can happen, this can happen. All that cable and kinetic energy has to go somewhere.
If your bad guys can get high enough to sever your cable, they can get high enough to do a kinetic or powered bombardment and cause magnitudes more damage.
¿Por qué no los dos?
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.
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.
If a tether breaks high up, then only a few kilometers of the tether hit the ground. Anything higher burns up on the way down (since it is very thin, so surface plasma heating doesn't take long to destroy it)
They're probably better off just flying into a building again.
The structure wouldn't be able to passively stay together. If it was to be destroyed then it would burn up in the atmosphere like anything else. It is not made of a magic non-existent material that is infinitely strong. Of course if you had a massive dense asteroid attached that would not, so it makes sense to be careful with what is around it. But the orbital ring itself would break up and be no more dangerous than a bunch of satellites of similar mass.
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.
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.
To the extent that an elevator would represent both the power and interests of whatever rich entity had managed to construct it, it would be a target for those who want to reduce the power and harm the interests of that entity.
>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.
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.
I'm more concerned about what's already within our atmosphere and isn't going to burn up. That's a lot of kinetic energy, and nobody says it's going to destroy the Earth, I said it would be devastating.
You're forgetting religious extremists and countless suicide bombers.
You're forgetting religious extremists and countless suicide bombers.
It would be cheaper to drop an equivalent massed object out of a plane. Or just use the plane as the weapon.
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.
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.
> "crashes" down, at a relatively low terminal velocity
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!
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!
That’s assuming you can’t say detonate a bomb inside the cargo thus resulting in vastly longer section falling down.
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.
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.
Accidentally deleted a bit: Space elevators are inherently a means to reach orbit so they create …
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.
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.
That's true-ish, but don't forget that a space elevator is also an enormous amount of orbiting mass all on it's own. So a small bomb can cause it all to come down and wrap around the planet twice.
For a ring with a density of 10kg/m, that kinetic energy is about 5 megatons… spread over 40,000km.
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.
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.
That fails to illuminate very much.
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.
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.
Assuming the cable is rated for the sudden force changes and won't get split into a whole bunch of smaller pieces that will drop at just their terminal velocities. Think a shower of cable pieces rather than a whip. Not great, but it's likely that most of the energy will be dissipated by the atmosphere.
And you’re both forgetting war.
"Above this altitude is known as the 'death zone', because there isn't enough oxygen for human life."
whooper swan casually floats by
whooper swan casually floats by
This is great.
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).
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).
That is mostly because the international space community works with metric, so the Karman line is at 100km above earth, and converting to imperial units would be forced.
Remember, there are only three countries that use imperial units; two third-world counties, and a global superpower.
Remember, there are only three countries that use imperial units; two third-world counties, and a global superpower.
The US doesn't use imperial units: it uses "US customary" units. Some of them are the same, but others are not. For instance, a gallon in the UK is very different from a gallon in the US, which causes miles-per-gallon ratings to be quite different between the two countries. The UK's gallon is properly called an "imperial unit" since the British actually had an Empire; the US did not.
That’s not entirely true. The UK and Australia use Imperial measurements quite frequently, especially for speed.
Colloquial speed yup. Not scientific speed which is m/s
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
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
hi, i’m australian, the only time i ever use imperial is if i work with hydraulic hoses or (rarely) tell someone my height
we pretty much only use metric, unlike the uk
Also Australian, can confirm although TV/monitor screen sizes are also usually expressed in inches.
We also haven't made the switch to metric time yet ;)
We also haven't made the switch to metric time yet ;)
Here in Japan, TV screens are also in inches. But they don't call them "inches" usually; instead, they're marketed as "85 type" (for an 85-inch screen).
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I’m a simple hacker news lurker. When I see a post that links to Neal.Fun I click. Always such high quality work
Me too! They are always great.
That was absolutely fantastic. I just left a pretty rough meeting and came to HN for some healthy procrastination.
Really made my day.
Really made my day.
I don't usually complete these little "fun internet" experiments but I thoroughly enjoyed this journey from start to end, and learned a bit on the way. My mind was blown a few times checking on the scrollbar thinking it's always over only to see we've barely just begun. Excellent.
It's not the first time I happen upon Neal's fun experiments, and I always love them.
As soon as I see the domain neal.fun, it is a must click.
As soon as I see the domain neal.fun, it is a must click.
Correction: almost* not always.
Amazing visualization. The most interesting part to me is the weird fluctuation in temperature. You'd think it would trend in a single direction. What causes all the frequent ups and downs?
At 17446m mark:
> Unlike the troposphere, the temperature in the stratosphere increases the higher you go.
> Unlike the troposphere, the temperature in the stratosphere increases the higher you go.
There's a graph here: https://pressbooks.bccampus.ca/physgeoglabmanual1/chapter/la...
Right, but that's an 'effect', not a 'cause'.
Ah yes, I thought, scrolling past the Learjet 45, the de Havilland Vampire, the Caproni Ca.161, all high-tech jet aircraft of the space age... hang on, the Ca.161?! I must say I'm sceptical that such a single-engined biplane could reach 50000 feet. The most advanced piston-powered aircraft, the four-engined Lockheed L-1649 Starliner, had a cruising altitude of no more than 30000 feet.
A key point with space elevators is that they aren't limited to Earth. The solar system has plenty of celestial bodies that could benefit (us) from having one.
It may not be as significant as the impact of an Earth-based one, but any propellant savings is a win.
It may not be as significant as the impact of an Earth-based one, but any propellant savings is a win.
Some of those celestial bodies are even small enough that we could build the elevators with existing materials, too.
A space elevator on Mars is probably totally feasible. But of course the benefits would be much larger on Earth.
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?
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?
Yes, it absolutely has to taper, with an exponential curve, to keep stress constant over the length of the cable. The taper ratio (in terms of cross-sectional area) for the best currently available engineering materials for an Earth space elevator would be in the tens to hundreds of millions, but a carbon nanotube cable might only require a taper ratio of around ten. (A steel cable would need a taper ratio on the order of 10^33.)
I believe A taper ratio of 10 means a 5cm rope at the bottom would be 50cm at the top.
A steel cable would be 1mm thick at the bottom and several light years* thick at the top.
*hyperbole. Maybe.
A steel cable would be 1mm thick at the bottom and several light years* thick at the top.
*hyperbole. Maybe.
It’s a function of area so if we scale equally in both dimensions, a taper ratio of 10 means a thickness ratio of ~3.2. But yeah, that doesn’t exactly buy us much.
> *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.
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.
The designs already have to taper, so you're right, but you still need supermaterials (or powered/active support structures) to make one on Earth.
The Moon being a great example.
A martian space elevator is explored in Kim Stanley Robinson's Red Mars trilogy, definitely worth a read.
I thought it would go all the way up to the anchor of the space elevator, so I expected to have to scroll up for another couple of hours. I guess the creator wisely decided that was a bit too much.
Amazing how high the F-104 Starfighter could fly, by the way.
Amazing how high the F-104 Starfighter could fly, by the way.
> Congratulations! You have made it 0.01% to the moon.
Okay, haha, now that gives a nice perspective how far is the Moon.
Okay, haha, now that gives a nice perspective how far is the Moon.
I’m impressed with how high planes and rockets built almost 100 years ago got.
Slightly tangential, slightly more achievable (?) , but I was just listening to a BBC Worldservice Radio Podcast on Space based Solar farms that would beam concentrated energy back down to earth [1]. By no means a new idea but they wrap up current thinking in 30min.
[1] https://www.bbc.co.uk/sounds/play/w3ct5bjt
[1] https://www.bbc.co.uk/sounds/play/w3ct5bjt
I used to think that the space elevator is a great and necessary concept for building a space-based civilization. How else can we get enough raw physical material into space? There's no way rockets can scale up to the enormous tonnages that will be required.
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).
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).
This is beautiful. I cried. And then I bought Mr Neal a coffee.
the space elevator.. it is a story of human progress .. it is something we will get to build one day
the space elevator.. it is a story of human progress .. it is something we will get to build one day
The space elevator music was particularly good.
Time of useful consciousness would be another interesting number to add. Here's a table of average times published by the FAA for a gradual ascent:
- 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
- 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
As cool as space elevators are - I wish all the other "easier" to build options would be more mainsteam. Say orbital hooks or maybe some of the more sedate active support structures like orbital rings or lauch loop variants.
Wow, this is beautiful and well done.
Also, didn't realize how badass Monarch Butterflies are.
Also, didn't realize how badass Monarch Butterflies are.
A scrolly solar system with a similar presentation style: https://joshworth.com/dev/pixelspace/pixelspace_solarsystem.... , https://hn.algolia.com/?query=If%20the%20moon%20were%20only%...
Things I learned here:
- 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)
- 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)
The Cessna part is wrong, I can reach over 4000 m in one. The only problems are lack of pressurization and the quantity of fuel to burn to get there, not actually reaching it. In a good day (cold weather, air more dense) it can get even higher.
If this is true, I predict we will find LeVar Burtons at 7000m.
> Temperatures in the thermosphere can reach 2,500°C, but molecules are so far apart that you wouldn't even feel it.
How do the molecules reach that temperature?
How do the molecules reach that temperature?
They absorb solar radiation. It can't be stressed enough though, that people understand temperatures in terms of the ability to transfer heat and store energy. Due to the extremely low pressure, both of these are actually very, very low.
For todays lucky 10,000.
Arthur C Clarke wrote a great story about space elevators called "The Fountains of Paradise".
https://arthurcclarke.org/site/legacy/fiction/fiction-sz/
Arthur C Clarke wrote a great story about space elevators called "The Fountains of Paradise".
https://arthurcclarke.org/site/legacy/fiction/fiction-sz/
Wow, I really love these sites. Reminds me of years ago when things on the internet were more fun... sure a bit janky but people just went to town and built stuff they wanted.
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!
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!
(Sorry, am not a science person). Why does the temperature go down until 11000 metres, then stay at -70F until 20000m, then starts going back up to 28F until 50000m, then starts going down again 83500m, stays at -119F until 90500m, rises up again until 100000m ?
That is the measured air temperature, but it isn't used the way we normally think about it. At very high altitudes, the atmosphere is very sparse (i.e. very low pressure). There are not very many molecules of air, but those few do get hit with a lot of ionizing radiation, meaning they have a lot of energy.
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.
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.
It shows temperature and altitude... would be very interesting if it also displayed pressure.
EDIT: and curves.
EDIT: and curves.
This was great!
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.
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.
You may have to toggle the "Australian mode".
Not with mine. You have your trackpad set reverse to mine which is default in some systems because kids expect it to work more like a smartphone/tablet rather than a scroll wheel.
I just have it at Apple default. It is the same as scrolling windows, but "up" is interpreted differently, in my brain (not a kid. I'm an old fart).
I handed this to a 12-year-old and am now having trouble getting him off the site for day #2 in a row; between Space Elevator and the rest of Neal.fun it's a whole new world for him - love it!
Simply beautiful.
This is absolutely fantastic, I'm sharing it with everyone I can :)
Height is in m, but temperatures are in f. Complete unusable :)
I loved this.
I loved this.
Click on it - the unit changes
FYI, this crashed my browser with extreme prejudice; I can't remember one other time when I've had to force-stop the application. (Firefox on Android)
Using firefox on android and it worked perfectly fine.
Sounds like another good reason to move on from Mozilla.
That would require a reasonable alternative.
Or perhaps a reason to update Windows https://news.ycombinator.com/item?id=35511713
The comment I replied to said that they use Firefox on Android. What relevance does Windows have to Android in this discussion? None.
Well I didn't see that. My apologies!
Wow, this is charming!
Very very nice. Love the details and the °F/°C toggle.
"...above this altitude your saliva and tears will boil if you don't have a pressure suit." :-$
"...above this altitude your saliva and tears will boil if you don't have a pressure suit." :-$
And it puts a suit on for you if you don't select one. No stickman snuff animations here.
Very cute way of conveying this information. Love it.
This is great! But also, in case you missed it, click back to the homepage. There are a bunch of other equally great diversions.
What is a pigeon doing at 2000 meters altitude?
What is a human being doing at that altitude? Flying.
S..itting on people below.
I wonder about the skydiver at almost 3000 m altitude. Isn't 4000 m a typical jump height?
Edit: Okay, depends on where you live and learn.
Edit: Okay, depends on where you live and learn.
I learned that temperature drops until just before the mesosphere where it starts to increase before dropping again. Wild!
Very cool. Only wish we could switch from meters to feet the same way we can switch between Celsius and Fahrenheit.
Sprites are AWESOME! They look so cool, does anyone know a good place apart from wikipedia to read about them?
This was fun, thanks for the experience. :)
I see you can switch degrees from °F to °C, thanks.
Would be nice to have a switch from m to km, too.
I see you can switch degrees from °F to °C, thanks.
Would be nice to have a switch from m to km, too.
Now please somebody create this in the opposite direction :) Down the mariana trench and beyond.
Oh, you'd be surprised!
https://neal.fun/deep-sea/
Very impressive. So few entertaining websites of this type these days. I really enjoyed it
Absolutely beatiful. And using the metric system, how refreshingly un-American.
Doesn't seem to work on my phone - it won't scroll at all.
iPhone SE 2016 - iOS 15.7.3
iPhone SE 2016 - iOS 15.7.3
I always enjoy using this site.
Anyone know the tech stack used to make these?
Anyone know the tech stack used to make these?
Caproni Ca.161 1938 altitude record
Insane. 17k meters.
Also there were many others which surprised me.
Insane. 17k meters.
Also there were many others which surprised me.
This was absolutely wonderful ... A perfect way to start my day
I don't understand why so many seemingly educated people keep discussing Earth space elevator. For a long time there is a conclusion that the elevator is incompatible with Earth satellites, which mostly fly below GEO, and elevator will collide with satellites, with all negative consequences. The inherent elevator problem has nothing to do with the material of the cable.
Am I missing something?
Am I missing something?
To me, a long-time sci-fi reader but hardly a hardcore space nut, your argument reads a little like "I don't understand why people are discussing horseless carriages, I mean what would the street sweepers do without all the manure to clean up?".
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. :)
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. :)
No, a better comparison would be "why people discuss antigravity sleds". Space elevator could have uses, if it wouldn't conflict with reality about as much as antigravity sleds, levitating a meter above the road, are.
Horseless carriages in this comparison are rockets.
Horseless carriages in this comparison are rockets.
Space is big. 1) The cable's vibration resonance can be adjusted to avoid the bulk of larger objects, 2) new satellites can be mandated to have emergency maneuver systems (with larger objects not yet de-orbited cleared out by an elevator consortium), and 3) the cable will necessarily have close range defense systems probably at intervals for smaller objects that might be harder to detect at long range. The cable, also, is enormous, which is the largest barrier to its implementation - it would dwarf every other artifact in human history, put together - and can not be made with any material we can currently create at scale. Compared with that, orbital TCAS of some sort is fairly trivial. In the long term, a space elevator is inevitable, but it's inevitable in the same way that . . I dunno, human-crocodile hybrids are, or fusion drive, or the way a lot of other medium-term future stuff is.
EDIT Also, this thing stops at the Karman line. That's not a viable space elevator. Pretty widget, though.
EDIT Also, this thing stops at the Karman line. That's not a viable space elevator. Pretty widget, though.
> In the long term, a space elevator is inevitable
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.
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.
Space elevator is by far the most efficient though . . right? Stuff that's on the end of the cable has enough angular velocity to get flung all across the inner system. Lunar orbit could be reached with release at 50,960 km. At the end of a 144,000 km cable you could get to Jupiter. I dunno what sort of other zero fuel launch techniques are getting considered though - there's no doubt a space elevator is just out of our capabilities today and for a while yet. Probably until our automation is good enough for self-directed asteroid factories to be a Thing.
The zero fuel options all sit around the same efficiency possibilities. A launch-loop won't get you as far as a GEO space elevator, but it can get farther than a non-stationary one. A sky hook can in theory get you a larger delta-v than a GEO elevator. A space fountain can do GEO, but no further...
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.
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.
I think the space-elevator concept is sort of silly, but this doesn't seem like the most pertinent criticism to me. Presumably in a hypothetical future in which a space elevator is under serious consideration, vastly greater resources are being devoted to space technology, launch costs are much less than now, and are about to get cheaper still due to the elevator in question. It seems like if we were on the cusp of being able to 100x the number of satellites or whatever, sacrificing the existing fleet for new ones in different orbits that avoided the elevator wouldn't be too big a sacrifice.
1) It's the only static non-rocket launch system. As such it doesn't require people to buy into the "active support structure" concept which is a prerequisite for orbital rings (<3), launch loops, or space fountains. (Rotovators, though arguably static, require exotic setups for terrestrial use.)
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.
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.
It's an idea that straddles science fiction and reality, but is simple enough for normal people to understand and have an opinion about.
Cause they are fucking rad! Its grandiose and big but plausible, its like some one heard of archimedes lever and took it as a challenge. Basically it sparks the imagination :)
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.
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.
Maybe because it's an old idea, from a time when non-GEO satellites were rare?
(when I was a kid in the 60s/70s, the cool thing was geostationary satellites)
(when I was a kid in the 60s/70s, the cool thing was geostationary satellites)
GEO is harder to achieve than LEO. There was never time when non-GEO satellites didn't outnumber GEO ones.
As satellite density increases every satellite will need a collision avoidance system anyway. And getting from geo to leo is way less difficult than launching to leo from the ground.
It's not clear. Maybe satellites will be assigned flypaths, like in aviation? Or you can have either a short-lived satellite, a GEO sat, a well-maintained constellation for communications or observations, singular exceptions like Hubble - or go fly away from Earth? Or something else? Not sure it's good idea for space elevator engineers to trust as much that all satellites will always behave as they, space elevator engineers, absolutely require. The error cost is pretty high.
I'd now like to go down to the core, please!
Space elevator: an idea that resurfaces every 5 years or so, until the practicalities get (re)discovered.
Is there any prospect at all of a material strong enough to handle this?
Is there any prospect at all of a material strong enough to handle this?
Well. Neal. That was fun. Thanks
I love this. Space elevators are going to be here much sooner than it seems with carbon nanotube tech. :)
There's not been that much progress in the 20 years since Brad Edwards proposed the first actually feasible space elevator design. It's difficult to say whether ultra-strong CNT cables are something that's perpetually 20 years away, or something that follows the "progress is slow until it suddenly isn't slow" exponential curve.
Would be cool, but as far as I understand, even long, continuous carbon nanotubes wouldn't be strong enough to carry their own weight.
Not if the cable has constant cross-sectional area, but actual designs call for a cable with an exponential taper, and that would make a carbon nanotube cable feasible. With currently available engineering materials the taper ratio would be too large (~10^8 for Kevlar, ~10^33 for steel…)
And I thought the cable had to be made of spider silk hadn’t?
Too bad someone will write an article titled "Will we get space elevators sooner than we think?" and Betteridge's law will prevent it from happening.
I enjoyed that greatly.
Amazing website.
So cool!
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.