What If Rockets Actually Burned Money?
Keith’s note: I have no idea if this is even remotely accurate in whole or in part (seriously doubt it). But it sure is funny. Anyone who has different math, please feel free to post. According to a post on Reddit:
“The fuel costs are, according to Musk, about $400.000. Let’s round that off and say 500.000, so that the empty rocket costs 56 million.
The Falcon 9 carries about 475 tonnes of propellant. If we can convert dollar bills into kerosene and oxygen perfectly, using 1 dollar bills and assuming a mass of one gram, we get a fuel cost of 475 million dollars. So, now a Falcon 9 costs 531 million dollars, and lifts 13150 kg. That’s 40380 dollars/kg. The space shuttle cost 1.5 billion dollars per flight including everything, and could get 25 tonnes into LEO, so that’s 60.000 dollars/kg.
Holy crap, you’re right. (don’t take this too serious.)
Edit: If we can convert dollar bills into kerosene and oxygen perfectly. Stop telling me that paper doesn’t burn hot enough.”
Interesting but we really need an apples-to-apples comparision, which I would like to see myself. Shuttle vs Falcon 9, manned vs unmanned, and differences in complexity as well as changes in the value of dollar make for difficult comparisons. Better to see Falcon 9 vs Titan or Delta heavy, and maybe later with Saturn V. Either way, its a deep and expensive gravity well.
I found a good analysis here: http://youtu.be/KTwnwbG9YLE
This burning cash as propellent math doesn’t make for anything other than a some funny phrasing. It’s incorrect math, being inconsistent (even after granting the humor of the dollar as fuel thing).
Notice the math uses propellent as money for Falcon (yielding a cost that is 10 times higher than the actual value) but then switches gears and uses the actual value of cost for the Shuttle. One might think this is a subtle attempt to confuse people about the costs of Falcons, that have gotten so much attention, after the end of the Shuttle flights?
For the record-
Shuttle at $3.3B a year (today dollars) for 5 flights (average of the program), meaning $845M per flight, with 24,400kg to LEO (200km/28.5 circ.) per flight would be $34,623 per kg.
Falcon (v 1.0) at $58M a flight, with 10,454kg to LEO (same orbit) per flight would be $5,548 per kg.
Adding in the non-recurring development costs of Shuttle before 1981 (and adjusting for inflation), and later development costs that were ongoing for 30 years until retirement (upgrades, a replacement orbiter, etc. as capital expenses) makes the Shuttle $/kg numbers go up, of course. Making an adjustment for crew being in the capability could be done if comparing to another crew carrying system (and it’s spacecraft).
Adding in the non-recurring development costs for Falcon would not change those numbers appreciably, as you would be starting with a relatively small number there (~$300M, and recently). The recent upgrade of Falcon to v1.1 added significantly more payload (another 3000kg) but not much as far as a price increase. So that v1.1 would make that Falcon $/kg number look even better.
The density of paper is much lower than LOx. (Although it’s not far from room-temp RP-1.) So you’d need bigger tanks unless you mixed in some higher denomination notes.
[Back of the envelope says 465 m^3 for 475 tonnes of RP-1/LOx at 1:2.5. But 540 m^3 for 475 tonnes of US one dollar bills, assuming perfect stacks and no air-spaces.]
However, the shuttle burned low density LH, so the main tank probably had enough space for a tonne for tonne conversion to paper currency.
But paper, being mostly cellulose, has a major deficiency of oxygen (n.C6.H10.O5), so it wouldn’t convert perfectly anyway, no matter how good your Acme Molecular Rejigger is. (The ratio of C/H isn’t bad for a simple hydrocarbons however. (RP-1 centres somewhere around C12H26, IIRC.))
All up, I think we’ll have to keep converting money into rockets the old fashioned way.
“The density of paper is much lower than LOx. (Although it’s not far from room-temp RP-1.) So you’d need bigger tanks unless you mixed in some higher denomination notes.“
Well, then, let’s take rockets right out of the equation for a moment. What we really need is a device that will convert bills into higher denomination bills with the application of increased pressure (and the process should ensure that they retain their denomination increase after the pressure increase is removed). It seems to me that a few of these machines running 16 hours a day could solve a lot of space program problems — but only temporarily, of course. However, think of what we could accomplish before the bean counters caught on!
Pretty sure that’s just called “Inflation”.
Yep! Now I can pry my tongue out of my cheek. To be precise, it’s what economists call the ratchet effect, and through the years it’s probably been the biggest problem that our economy has had to face (everything goes up; nothing comes down; except our real wealth).
Actually deflation is pretty bad for an economy too.
Actually dollar bills are mostly cotton I believe. Not that that invalidates any of what you said.
It would be great to combine this with Project Denarius.
http://www.theonion.com/art…
The good thing about using dollars as fuel is that it seems that the Fed has no problem printing a lot of extra money when needed, so if we don’t have enough to get to Mars or wherever the Fed can simply print more.
The catch is, like regular money, the more “fuel” you print, the less each kg of fuel will lift.
There is a time lag before the value goes down, so the rocket will be on its way to Mars by then and will be unaffected. Future programs will suffer, but when has that ever stopped a brilliant short-term solution.
Oh!!!!
So that’s why it getting harder for me to make ends meet!!!
Thanks Steve
🙂
Why not a rocket that burns gold?
And turns the gold into lead for shielding?
Since we’re looking at alternative fuel sources, we’re once again going through a period when balloon experiments are useful. Balloons require lots of hot air to operate. Considering the large numbers of politicians in many countries who are sitting around doing nothing useful except generating hot air, well… you can take it from there.
This is a whole new take on the concept of cash burn rate.
That is like the disposable Orion capsule I always called it the gold plated capsule, until someone figured out .. it would be cheaper to build the capsule out of SOLID DIAMONDS then the 16.5 billion is currently going to cost us.