Inter System Travel

[Duke Wellington]

I personally believe it has already been done by the Americans in secret. The technology already exists to do it, although I think that would surprise many. So here we go:

1. Heated objects expand. If we heat water it expands, it turns into a large steam cloud, and if we heat that steam cloud it grows even larger too.

2. We have nuclear reactors capable of powering high megawatt lasers. Zapping a tiny droplet of water with such a laser to heat it would turn it into a very large vaper cloud.

3. The tiny rate at which water would be consumed by this process would mean a spaceship could have enough fuel for a long voyage with just a 100 galleons of water.

4. Put all the above onto a spaceship and off we go. We have the fuel to provide thrust for decades of accelerate.

Limiting factors - Human beings can only be accelerated at 1-2g over long periods of time before it causes health problems. This means we cannot fire up our nuclear powered spaceship at 500g. Additionally, if something goes wrong during a flight lasting 50 years to the next star system and back the crew are dead. Finally we dont know how much debris exists in interstellar space meaning there is a chance the spacecraft could be destroyed.

Of course taking a high powered nuclear reactor, a high powered laser, and putting them onto a spacecraft with all the other things needed would be an expensive engineering project.

[Rlyeh]

Not surprised you of all people would come up with something so asinine.

Ignoring the fact a droplet of water could never turn into a large vaper cloud to begin with.  How much energy would a drop of water transfer to a spaceship carrying a nuclear reactor?

[Duke Wellington]

15 hours ago, Rlyeh said:

Not surprised you of all people would come up with something so asinine.

Ignoring the fact a droplet of water could never turn into a large vaper cloud to begin with.  How much energy would a drop of water transfer to a spaceship carrying a nuclear reactor?

The thermal expansion of liquids and gases is high school chemistry.

If we take a thermometer off the wall, put it in the fridge for 10 minutes, record where the mercury is at and then put the thermometer in hot water we can see an impressive expansion. Water expands by about 4% when heated from melting to 100C.

When boiling water at 100C turns into steam the volume of steam is x1600 that of water. This is why steam locomotives are able to pull a train of carriages. What we would be doing to achieve high thrust with our spacecraft is not using that expansion of volume to drive pistons, but by using it as a source of thrust. To do so would mean we need a high powered laser to zap our droplets of water to several million C. Steam continues to expand in volume the higher its temperature and that expansion of steam follows an inverse law.

I really cannot believe I had to explain that.

And we cannot go past an acceleration of 1-2 in the long term if humans are onboard as it would cause health problems. But, if all we need is an acceleration of 1-2g to propel a spacecraft weighing say 10,000 tonnes then it doesnt require even a rocket booster sized tank of water for decades of flight.

Edited December 19, 2020 by Cookie Monster

[Rlyeh]

22 minutes ago, Cookie Monster said:

The thermal expansion of liquids and gases is high school chemistry.

You should've paid more attention then.

 

Quote

If we take a thermometer off the wall, put it in the fridge for 10 minutes, record where the mercury is at and then put the thermometer in hot water we can see an impressive expansion. Water expands by about 4% when heated from melting to 100C.

When boiling water at 100C turns into steam the volume of steam is x1600 that of water. This is why steam locomotives are able to pull a train of carriages. What we would be doing to achieve high thrust with our spacecraft is not using that expansion of volume to drive pistons, but by using it as a source of thrust. To do so would mean we need a high powered laser to zap our droplets of water to several million C. Steam continues to expand in volume the higher its temperature and that expansion of steam follows an inverse law.

I really cannot believe I had to explain that.

It's called handwaving.  

A drop of water will never become a large vapor cloud.

Not to mention steam never gets close to a million C.

https://en.wikipedia.org/wiki/High-temperature_electrolysis

 

Quote

And we cannot go past an acceleration of 1-2 in the long term if humans are onboard as it would cause health problems. But, if all we need is an acceleration of 1-2g to propel a spacecraft weighing say 10,000 tonnes then it doesnt require even a rocket booster sized tank of water for decades of flight.

Where do you get 1-2g from a drop of water?  You can answer the question can't you?

Edited December 19, 2020 by Rlyeh

[XenoFish]

If you're going to use water as a propellant then you need to separate it into hydrogen and oxygen. 

Liquid Hydrogen--the Fuel of Choice for Space Exploration

Despite criticism and early technical failures, the taming of liquid hydrogen proved to be one of NASA's most significant technical accomplishments. . . . Hydrogen -- a light and extremely powerful rocket propellant -- has the lowest molecular weight of any known substance and burns with extreme intensity (5,500°F). In combination with an oxidizer such as liquid oxygen, liquid hydrogen yields the highest specific impulse, or efficiency in relation to the amount of propellant consumed, of any known rocket propellant.

https://www.nasa.gov/topics/technology/hydrogen/hydrogen_fuel_of_choice.html

https://www.energy.gov/eere/fuelcells/hydrogen-production-thermochemical-water-splitting

Edited December 19, 2020 by XenoFish

[Duke Wellington]

55 minutes ago, XenoFish said:

If you're going to use water as a propellant then you need to separate it into hydrogen and oxygen. 

Liquid Hydrogen--the Fuel of Choice for Space Exploration

Despite criticism and early technical failures, the taming of liquid hydrogen proved to be one of NASA's most significant technical accomplishments. . . . Hydrogen -- a light and extremely powerful rocket propellant -- has the lowest molecular weight of any known substance and burns with extreme intensity (5,500°F). In combination with an oxidizer such as liquid oxygen, liquid hydrogen yields the highest specific impulse, or efficiency in relation to the amount of propellant consumed, of any known rocket propellant.

https://www.nasa.gov/topics/technology/hydrogen/hydrogen_fuel_of_choice.html

https://www.energy.gov/eere/fuelcells/hydrogen-production-thermochemical-water-splitting

Burning hydrogen is okay for a rocket going into orbit or the Moon but it isn`t practical to use rocket propellant for long voyages.

It doesnt matter if at high temperature steam breaks into hydrogen and oxygen, and if at a higher temperate those two gases become plasmas. All we are interested in is feeding in tiny droplets of water into a thruster and zapping it with a high powered laser. We are after the pressure expansion to provide the thrust out the back, not any chemical reaction. What happens to the steam, the oxygen and hydrogen, the plasma, is irrelevant, beyond our use which is to provide thrust.

We have the technology, we have nuclear reactors, we have lasers. It just requires the engineering project to put them onto a spacecraft. Currently nuclear propulsion for spacecraft hasn`t been developed (beyond whatever happened in the Orion Project) because of fears of what an exploding spacecraft could do to Earths environment.

20% the speed of light is achievable right now. Upgrade a nuclear reactor to a fusion one (something the French are currently working on for electricity) might well get that up to 40% by allowing us to heat that tiny droplet of water to 120 million C.

[XenoFish]

You're going to need to start providing supporting links instead of sci-fi babble.

[kartikg]

Dude turn on your stove, put a pan on it and heat it up till you feel satisfied, put an lid on it and slowly inject a drop of water and see if the lid flys with 1g of force.