Rockets are practically powered by flaming cash - how true?

[JebKeb]

I've been told this many times and I am wondering whether it is true. Here's my analysis.

Money in the US is made from about 75% cotton and 25% linen. Cotton is practically a special form of celluose, and linen is pretty similar. The combustion energy of celluose is 2828kJ/mol, and one mole of celluose is 630g, so we'll estimate and say 4mJ/kg due to the impurities in cotton and linen. 

Celluose probably has a pretty low isp, so I'm estimating it at 100 due to lack of data. To get 1 tonne to orbit, assuming a very light container, we'll need about 50 THOUDSAND TONNES of fuel! Let's say 60K, because of the complex machinery to combust such a non-rocket-fuelly propellant. 

That's 50 tonnes of cash per kg to space. Let's assume we're using 100 dollar bills, weighing 1g each, requiring $5,000,000,000 per kg to space. Present launch costs are on average about $12K/kg. 

Here is a list of different costs to orbit.

• 1 dollar: $50,000,000/kg
• 2 dollar: $100M/kg
• 5 dollar: $250M/kg
• The rest are obvious, so...
• 1 trillion dollar: $50,000,000,000,000,000,000/kg, or the GDP of 500,000 Earths.

So, it looks like this example is far off. Let's see if there are any other comparisons.

 

[Bill Phil]

Wait, I thought that rockets are just expensive printers that printed money for us?

In all honesty, though, a study in the 70s found that the space program stimulated the economy, with somewhere around 25 billion USD in 1958 dollars invested, and over 50 billion USD (also 1958 dollars) were given back to the economy. The study also found that it would continue to generate returns into the 80s. I'm not sure about now, though.

[Kerbart]

3 minutes ago, Bill Phil said:

Wait, I thought that rockets are just expensive printers that printed money for us?

If they ran on printer ink maybe. But rockets are not that expensive.

[Scotius]

So. If that data are correct, for every dollar we shoot into space, two dollars fall back. Quick! Someone show this to relevant authorities - space is a cash making machine!

[Nuke]

as i understand it the rocket is actually the cheap part. things like mission control, launch facility operations, use of space communication infrastructure for the duration of the mission, the people you need to pay for months or years, regulatory fees, insurance. those cost money.

Edited July 9, 2016 by Nuke

[todofwar]

On Friday, July 08, 2016 at 7:23 PM, JebKeb said:

I've been told this many times and I am wondering whether it is true. Here's my analysis.

Money in the US is made from about 75% cotton and 25% linen. Cotton is practically a special form of celluose, and linen is pretty similar. The combustion energy of celluose is 2828kJ/mol, and one mole of celluose is 630g, so we'll estimate and say 4mJ/kg due to the impurities in cotton and linen. 

Celluose probably has a pretty low isp, so I'm estimating it at 100 due to lack of data. To get 1 tonne to orbit, assuming a very light container, we'll need about 50 THOUDSAND TONNES of fuel! Let's say 60K, because of the complex machinery to combust such a non-rocket-fuelly propellant. 

That's 50 tonnes of cash per kg to space. Let's assume we're using 100 dollar bills, weighing 1g each, requiring $5,000,000,000 per kg to space. Present launch costs are on average about $12K/kg. 

Here is a list of different costs to orbit.

• 1 dollar: $50,000,000/kg
• 2 dollar: $100M/kg
• 5 dollar: $250M/kg
• The rest are obvious, so...
• 1 trillion dollar: $50,000,000,000,000,000,000/kg, or the GDP of 500,000 Earths.

So, it looks like this example is far off. Let's see if there are any other comparisons.

 

Your combustion products will be CO2 and H2O, in equimolar ratio I believe. So the ISP would probably be close to kerolox. A bit lower, since hydrocarbons spit out a higher ratio of water. 

[WinkAllKerb'']

 

*slighty sliding side of topic mode on*

i think if every being on earth fart at the same time in  the same location we might get enough isp to reach the moon xdr

any way most fart while sleeping, weird

*slighty sliding side of topic mode off*

Edited July 10, 2016 by WinkAllKerb''