# How to go to Space

#### Cognisant

##### Prolific Member
The first problem is getting stuff out of Earth's gravity well and let's examine that for a moment.

Orbital velocity at sea level is about 7.9km/s and it slowly goes down as you gain altitude, at 100km orbital velocity is 7.84km/s at which point the atmosphere is so thin you're practically in space. What this means is that going to space is more about going fast than going up, a rocket will go straight up for the first few minutes of its flight but that's just to get out of the densest part of the atmosphere in order to reduce drag so it can get on with its real purpose, going really really fast.

At this point in time rockets have reached an efficiency plateau, an extra 1-2% does equate to significant savings on launch costs and having reusable rockets has brought SpaceX to the forefront of the aerospace industry, but fundamentally rockets will always be risky and expensive. Unless there's some incredible breakthrough in metallic hydrogen or fusion candle engines space industry is going to going to stay in low Earth orbit with a few telescopes and probes funded by governments. A manned mission to Mars is not likely to happen except maybe as a joint venture between SpaceX and NASA and even then it's going to be a bare minimum go-there-to-plant-the-flag affair, not a colony.

The problem is cost and the cost problem is an industry problem, because space is such an incredibly dangerous and unforgiving environment you need a lot of equipment and infrastructure (and redundancy) just to survive, and that equipment and infrastructure needs its own equipment and infrastructure (and redundancy) to build and maintain it. Finally all of this needs to be sent into space on incredibly expensive rockets which even if they're reusable they're still expensive and they can still only be used so many times without a complete overhaul, at which point you may as well build a new one.

If we're serious about having industry in space we need infrastructure in space and to make that infrastructure we need to bootstrap mining, refining, smelting, machining, automated factories and shipyards, we're talking about a production line churning out a hundred Falcon 9 rockets to perform several hundred missions in total. Going to space is a large scale problem and bootstrapping industry in space is an exponentially bigger problem and to tackle this problem we need something that can operate on that scale, the Sea Dragon is a step in the right direction but we need to think bigger.

We need to start talking about mass drivers, yes on Earth, yes through the densest part of the atmosphere.
Fuck all pretense of subtlety.

This mass driver is going to need to be very long so I'm going to assume it's in a tunnel underground and ideally it should exit high up in a mountainside but given that at these speeds the barrel needs to be almost dead straight (especially near the end) I'm just going assume it comes out at just above sea level. Now anything moving at re-entry speeds at sea level is going to have a very bad day, as is everything in the general vicinity, as the projectile rapidly reaches surface-of-the-sun temperatures and turns into plasma.

This is good, this is what we want, specifically the shock wave that moves a lot of atmosphere out of the way, because if we can fire enough shots in rapid succession we can make a hole in the atmosphere that goes all the way up, the long way, because we're firing sideways rather than up.
Rest assured this will not cause a fusion reaction. I'm about 90% sure.

Now we could fire several sacrificial shots every time we want to send a payload to space and these sacrificial shots can just be containers of water. At these speeds it's really only the mass that's important because the only way the mass can slow down is by displacing atmosphere and no matter what we use it's going to get turned to plasma, well maybe a big tungsten slug could survive (partially) but that would just be irresponsible.

But why go to all the effort of opening a hole in the atmosphere just to let it close again?
Once the hole is opened send through a constant stream of carriages and it can't close, the reason rockets tend to be long and cylindrical is that the greater your cross section and the faster you go the more atmosphere you displace and the more violently you displace it. The cross section of a cylinder is a circle and by bringing that circle to a point at the front you can hide as much of the volume of the craft within the smallest possible shock wave thereby minimizing drag.

So ideally you want your rocket to be as long and thin as possible but of course that's not practical, but with a series of carriages coming out of a mass driver you can have the theoretically optimal shape, a cylinder that's so long that once the the leading end has breached the upper atmosphere there's no longer any air displacement occurring. Skin friction drag isn't a factor either, not at these speeds, rather when the atmosphere closes in on the carriages the slightest bumps on their surface will create little shock waves so there will be some wave drag. But the fun thing about a circle is that for a linear increase in circumference there's an exponential increase in volume which means a proportional decrease in the significance of that drag (more volume = more cargo = more mass = more momentum).

Furthermore the air heated by these little shock waves is going to have a different velocity and density to the air around it resulting in a boundary between the two and this boundary layer of air between the carriages and the atmosphere acts kind of like the dimples on a golf ball, in theory. I don't really know and I haven't found any way to calculate it, possibly nobody knows and nobody cares because the wave drag of microscopic surface imperfections is usually negligible (or negated) by the shock wave from the craft's leading edges and overall profile.

Now the hard part is loading the mass driver fast enough to maintain a constant stream of carriages moving at 8km/s, the only way I could see this working is to have many mass drivers all converging on one track, each with a magazine of carriages that's being supplied from distribution centers which are themselves stocked by a worldwide supply chain. In order for this to work there needs to be enough redundancy for some mass driver stations to be down for maintenance while the others maintain the rate of fire and the same for the distribution centers and the ports and even the worldwide supply chain needs to be resilient enough to keep up with demand.

Compared to that herculean feat of logistics the millisecond timing required to get all the carriages to converge on one track to form one continuous hyper-sonic train is fairly simple.

Now the real cost savings come in the fact that you don't need atmospheric rocket engines anymore and these carriages are mostly just glorified cylindrical shipping containers, they're not even magnetic they're just steel because all the maglev is done by the mass driver tracks. Once these containers are in space they'll still need to be ferried to where they're meant to go because even if they're in space their trajectory isn't orbital until it's been adjusted but that's not much.

Any questions?
If people are interested I'll continue with the next phase, industrializing the moon.

#### Cognisant

##### Prolific Member
You'd think someone would be excited or call me stupid or... something.

#### scorpiomover

##### The little professor
The first problem is getting stuff out of Earth's gravity well and let's examine that for a moment.

Orbital velocity at sea level is about 7.9km/s and it slowly goes down as you gain altitude, at 100km orbital velocity is 7.84km/s at which point the atmosphere is so thin you're practically in space. What this means is that going to space is more about going fast than going up, a rocket will go straight up for the first few minutes of its flight but that's just to get out of the densest part of the atmosphere in order to reduce drag so it can get on with its real purpose, going really really fast.
Orbital velocity is the speed required to to orbit the Earth.

Escape velocity is the minimum speed required to escape the gravity of the Earth, which is a bit over 25,000 mph.

Escape velocity is about speed, because the solution to Newton's equation of gravity resolves to only constants and your speed away from the Earth.
The problem is cost and the cost problem is an industry problem, because space is such an incredibly dangerous and unforgiving environment you need a lot of equipment and infrastructure (and redundancy) just to survive, and that equipment and infrastructure needs its own equipment and infrastructure (and redundancy) to build and maintain it. Finally all of this needs to be sent into space on incredibly expensive rockets which even if they're reusable they're still expensive and they can still only be used so many times without a complete overhaul, at which point you may as well build a new one.
Moving stuff from the Earth to space and back, would be incredibly expensive.

Imagine if all the equipment and infrastructure in Australia had to be imported from the other side of the world. Would it really be viable to live there? Even mining there would be a nightmare.

To make a self-sustaining colony, you'd need to get things going in space so you could make everything you need without the Earth.

So getting hold of mining resources, the equipment to dig them out, and the equipment to make more machines, would be a priority.

Same for agriculture. Once you've got your first biodomes going, all you'd need would be more biodomes and seeds.
If we're serious about having industry in space we need infrastructure in space and to make that infrastructure we need to bootstrap mining, refining, smelting, machining, automated factories and shipyards, we're talking about a production line churning out a hundred Falcon 9 rockets to perform several hundred missions in total.
I think we'd run out of energy or money before then.

We need to start talking about mass drivers, yes on Earth, yes through the densest part of the atmosphere.
Fuck all pretense of subtlety.

This mass driver is going to need to be very long so I'm going to assume it's in a tunnel underground and ideally it should exit high up in a mountainside but given that at these speeds the barrel needs to be almost dead straight (especially near the end) I'm just going assume it comes out at just above sea level. Now anything moving at re-entry speeds at sea level is going to have a very bad day, as is everything in the general vicinity, as the projectile rapidly reaches surface-of-the-sun temperatures and turns into plasma.
The escape velocity also refers to the amount of energy required to leave the Earth's atmosphere. So a mass driver would still need to generate an electromagnetic field powerful enough to make anything metal travel at escape velocity, which is just over 25,000 mph.

I hesitate to think how much energy that would require.

This is good, this is what we want, specifically the shock wave that moves a lot of atmosphere out of the way, because if we can fire enough shots in rapid succession we can make a hole in the atmosphere that goes all the way up, the long way, because we're firing sideways rather than up.
This would resolve air resistance, but not gravity.

Rest assured this will not cause a fusion reaction. I'm about 90% sure.
I'm not.

Any questions?
If people are interested I'll continue with the next phase, industrializing the moon.
Yes.

How on Earth would you pull this off?

What are your numbers? How much would it cost to launch even ONE carriage?

How much would it cost every day to keep launching carriages as you suggest?

#### Cognisant

##### Prolific Member
Escape velocity is the minimum speed required to escape the gravity of the Earth, which is a bit over 25,000 mph.
Yes in "freedom units" that's the velocity required to exit the Earth's gravity well entirely, you would actually need to slow down to stay in orbit.

How much would it cost every day to keep launching carriages as you suggest?
Considering water can be used for radiation shielding, irrigation/hydroponics, direct consumption, hygiene, recreation, and via electrolysis turned into hydrogen and oxygen which is a very effective rocket fuel, how much it costs to send water into space is entirely relative to how much it costs everyone else to send water into space and at the current time you can send water to space via Falcon 9 at a cost of $2720 per liter, that's a bout one quart if you insist on the "freedom units". So if say sending water to space via mass driver costs 2700/L and you can sell it for 2720/L because your competitors can't compete without losing money and if each carriage/container has the same internal volume as a standard 20ft shipping container (33m^3) that's 33,000L and a profit of$660,000 per container and assuming these containers are about the same length as the shipping container (6m) to fire them in a constant steam of back to back containers at 8km/s that's roughly 1,333.3 containers per second.

That's $52,798,680,000 of profit per minute. #### scorpiomover ##### The little professor Escape velocity is the minimum speed required to escape the gravity of the Earth, which is a bit over 25,000 mph. Yes in "freedom units" that's the velocity required to exit the Earth's gravity well entirely, you would actually need to slow down to stay in orbit. Your orbital velocity would need to be along the tanjent. Your escape velocity would need to be perpendicular to the tangent. So I suspect that you'd need both to get into orbit. How much would it cost every day to keep launching carriages as you suggest? Considering water can be used for radiation shielding, irrigation/hydroponics, direct consumption, hygiene, recreation, and via electrolysis turned into hydrogen and oxygen which is a very effective rocket fuel, how much it costs to send water into space is entirely relative to how much it costs everyone else to send water into space and at the current time you can send water to space via Falcon 9 at a cost of$2720 per liter, that's a bout one quart if you insist on the "freedom units".
I can buy almost 2,000 litres of water for the price of one of your litres.

So if say sending water to space via mass driver costs 2700/L and you can sell it for 2720/L because your competitors can't compete without losing money and if each carriage/container has the same internal volume as a standard 20ft shipping container (33m^3) that's 33,000L and a profit of $660,000 per container and assuming these containers are about the same length as the shipping container (6m) to fire them in a constant steam of back to back containers at 8km/s that's roughly 1,333.3 containers per second. That's$52,798,680,000 of profit per minute.
If you are the only person in the world who can make a rocket that goes into space or a mass driver, and no-one lives on the Earth, and there's no water anywhere in the whole solar system, then yes, you can make lots of money.

1) Did you make the idea of sending rockets into space and patent the concept in every country in the world, so no-one else could?

Did you come up with the idea of a mass driver and patent the concept in every country in the world, so no-one else could?

So anyone else in the entire world could do that. 7.8 billion people could do that.

2) Nearly all humans live on the Earth, apart from the 20 or so astronauts who are on the ISS.

3) There's plenty of water in asteroids, comets, etc.

So it's possible to say you could earn over $52 billion dollars a minute. But I really doubt that you'd have the advantage here. More than likely, what would happen is that you could offer to ship water to the ISS. But I seriously doubt that whoever runs the ISS would be willing to pay you over$2,000 for each litre of water.

Now, since the average person is estimated to use 142 litres of water a day, I could see the advantage of your system of shipping 1,333.30 containers per second, each of which holds 33,000 litres, if you were the sole supplier of water to 26,771,161,690.14 people who all lived permanently in space.

But I think that's a mite over-optimistic.

I'd start with a Moonbase Alpha, buried deep under the Moon's surface, so you don't have to worry about keeping cool, and with retractable solar panels on both sides of the Moon, so you're always generating plenty of energy to keep yourself warm.

Then you can build all the devices you want in your Moonbase Alpha, to launch into space.

You can have all the room down there that you want.