totm nov 2023 SpaceX Discussion Thread

[kerbiloid]

Grid power is get from solat panels, which still must be produced from minerals.
Plastic, pure silicon, metals - all this require a lot of methane, both to produce and utilize.

[Rakaydos]

Just now, kerbiloid said:

Grid power is get from solat panels, which still must be produced from minerals.
Plastic, pure silicon, metals - all this require a lot of methane, both to produce and utilize.

Even if the grid was 100% solar power (again, you're leaving out wind) I believe the equation still balances on the side of renewables.

[kerbiloid]

One F9 spends ~500 t of fuel per flight.
Kerosene:O2 is usually ~1:2.5. Say, ~140 t of kerosene.
Kerosene = CH2. Say, ~120 t of carbon.
So, 160 t of methane should be produced per flight.

Which means at least 160000*1260 = 201600000 MJ per flight ~= 200 TJ per flight. Including wastes ~500 TJ at least.
Say, one flight per month = 30 * 86400 = 2592000 s.
500*1012/2592000=200 MW powerplant just to electrolyse water.

***

I can suggest more easy way to keep the carbon atmospheric balance ^(tm).
Let them buy 200 t of straw every flight and bury it in a mine, covering with sand.

Edited October 14, 2017 by kerbiloid

[Rakaydos]

1 hour ago, kerbiloid said:

One F9 spends ~500 t of fuel per flight.
Kerosene:O2 is usually ~1:2.5. Say, ~140 t of kerosene.
Kerosene = CH2. Say, ~120 t of carbon.
So, 160 t of methane should be produced per flight.

Which means at least 160000*1260 = 201600000 MJ per flight ~= 200 TJ per flight. Including wastes ~500 TJ at least.
Say, one flight per month = 30 * 86400 = 2592000 s.
500*1012/2592000=200 MW powerplant just to electrolyse water.

***

I can suggest more easy way to keep the carbon atmospheric balance ^(tm).
Let them buy 200 t of straw every flight and bury it in a mine, covering with sand.

That doesnt prepare them to make methane on mars, though...

(also, kerosene is C12H24)

Edit: https://en.wikipedia.org/wiki/Power_to_gas#Power_to_methane

It's good enough that car manufacturers are looking at it...

Edited October 14, 2017 by Rakaydos

[kerbiloid]

5 hours ago, Rakaydos said:

(also, kerosene is C12H24)

Kerosene is (CH₂)n. As well as petrol, etc.
C₁₂H₂₄ is just one of its fractions.
(Btw. It can't be C₁₂H₂₄, it should be C₁₂H₂₆. C_nH_2n+2).

5 hours ago, Rakaydos said:

It's good enough that car manufacturers are looking at it...

It's good enough for cars instead of petrol, which requires even more efforts than natural methane.
Of course, methane is enough cheap instead of kerosene/gasoline. Though propane+butane mixture is better due to higher melting point, lesser pressure in the tank to stay liquid.

***

While hiding 200 t of dry straw underground buries the same amount of carbon which Falcon throws per flight, and requires no additional efforts.
Any farmer nearby would be happy to save the Earth.

Edited October 14, 2017 by kerbiloid

[sh1pman]

They can also use wind or hydro power for electrolysis. 100% eco-friendly.

[kerbiloid]

2 minutes ago, sh1pman said:

They can also use wind or hydro power for electrolysis. 100% eco-friendly.

Unless you have to take a hydropowerplant from the power generation and provide all required supplies for its work.
Nothing is eco-friendly. Evil can be just redistributed.

While the straw is everywhere, like dirt.

Edited October 14, 2017 by kerbiloid

[sh1pman]

1 minute ago, kerbiloid said:

Unless you have to take a hydropowerplant from the power generation and provide all required supplies for its work.
Nothing is eco-friendly. Evil can be just redistributed.

Not as bad as burning hydrocarbons for energy.

[kerbiloid]

4 minutes ago, sh1pman said:

Not as bad as burning hydrocarbons for energy.

https://www.texastribune.org/2014/03/10/central-texas-drought-threatens-hydropower/

Btw, if the straw looks too vulgar, they can buy a coal mine, nearly depleted, and close it.
Thousands tons of coal carbon will never reach the air.

(But imho happy farmers are better than unhappy miners).

P.S.
Super-combo: to buy a nearly depleted coal mine and let the miners become farmers growing corn for food and its straw to bury in their mine.

Edited October 14, 2017 by kerbiloid

[tater]

 

[sh1pman]

@tater F9 launch?

[tater]

Yeah.

[.50calBMG]

Testing stage 2 landing?

[tater]

9 minutes ago, .50calBMg said:

Testing stage 2 landing?

No. SpaceX doesn't waste launches. Any S2 testing will be after another, paid mission, there is no way they throw away a S2 for nothing.

Might be military. I suppose there is a chance they mess with the max-Q abort... except RTLS.

[PB666]

4 hours ago, kerbiloid said:

Unless you have to take a hydropowerplant from the power generation and provide all required supplies for its work.
Nothing is eco-friendly. Evil can be just redistributed.

While the straw is everywhere, like dirt.

Not exactly true, in fact the statement is wrong.

In both Texas and Minnesota during the Winter there is wind turbine production that exceeds demand and the price of wind powered electricity drops to zero.

There are periods of electrical excess which could be used to generate hydrogen and oxygen for fuels provided an efficient means of hydrolysis.

The power plants associated with lake LBJ only run periodically as lake levels permit. Since I used to live in the hill country we used to go fishing below the damn, you have to be prepared to scramble when they turn on the power plant.

I agree that all forms of renewable power have their costs, that conservation is almost always the most eco-friendly and economical of the choices. But we also have to remember that our earth is not a static entity and that electrical demand is in flux with the seasons and diurnal cycle. Theoretically, for solar power you can have a nice cool day with no cloud cover where neither air-conditioning or heating are required, you have then excess. For this reason they only recommend that you solar power a third of your need.

OK, shifting this thread BACK to space travel and away from quasi-political discussions of a green disposition.

The primary problem, by a magnitude, is not eco-friendly sources of electricity BECAUSE you can't launch any kind of rocket with electric or battery provided power source for the ejection mass. ION drives do not work in the atmosphere. Given that electricity CANNOT be directly used as a propulsion source then the pertinent problem, by a magnitude, is efficient conversion of H20 (or CO2) and  e^-  into H-H, C-H or O-O bond energies. Again we are taking about 9e- of waste for each e- of bond. This on top of 2 to 3 hv of waste for each hv generating solar power. IOW in the conversion of solar hv to bond energies there is roughly one unit of bond energy per each 100 units of hv. This has to improve by at least a magnitude. Yes it is true that excesses of wind or solar power could be used to make H2, the problem is that it would not suffice to make they quantities required for a robust space program and would best be diverted to other functions.  Theoretically you could use that EMF to purify nuclear elements such as uranium or tritium, here again uranium power reactors in space are a fail, and nuclear fusion is still very early in the development phase (disregarding all discussion of the hideous Orion drive).

So we talk aspects of future economy (including a robust and efficient space program as part of an efficient energy economy) we are talking about current R&D towards an efficient application of green power and efficient conversion to conventional sources of propulsion (or hydrogen for hydrogenating tar sands and heavy crude to light crude and kerosene that has broader economics). We might also include this as part of a program to generate power closer to the demand sources in large cities, etc.

To get their means we need to use traditional fossil fuels including coal. This comes from someone who detests the renewal of coal fired plants for electricity when other sources of fuel are being made. Currently the largest source of solar power is china, and those panels are built with coal. Coals deep dark secret is that it kills the local environment, lignite coal is loaded with Mercury and a very foolish and short sighted society burns dirty simply for electric power. In addition to build rockets you need steel and to make steel you need coal, so . . . . . . . . Its all a dirty business . . . .evironmentally we humans are very exploitative and transforming, we cannot be us and not. The issue is doing it we less impact.

 

[kerbiloid]

Ok, it's cheaper to use a 200 MW hydro power plant than buy and bury 200 t of straw.

Upd.
I'm shocked. I suggest the greenest of the green way to return from the atmosphere all carbon dioxide exhausted by Falcon: just grow and bury a corn!
And I'm wrong because hydro power plant, wind generators or solar panels with electrolysis are more green than fresh plants...

Btw, Martian colonists must grow crops, and this would be a great R&D for the future Martian colony.

Edited October 14, 2017 by kerbiloid

[CatastrophicFailure]

2 hours ago, tater said:

No. SpaceX doesn't waste launches. Any S2 testing will be after another, paid mission, there is no way they throw away a S2 for nothing.

Might be military. I suppose there is a chance they mess with the max-Q abort... except RTLS.

Rapid response test for the USAF? Maybe their X-37 is broken and they gotta send the other to go fix it. 

Or maybe... they’re trying to sneak in that Falcon Heavy launch when no one is expecting it...

[TheEpicSquared]

1 minute ago, CatastrophicFailure said:

Or maybe... they’re trying to sneak in that Falcon Heavy launch when no one is expecting it...

I thought that as well, but FH  already has its launch license for NET December 2017.  

[tater]

8 minutes ago, CatastrophicFailure said:

Rapid response test for the USAF? Maybe their X-37 is broken and they gotta send the other to go fix it. 

Or maybe... they’re trying to sneak in that Falcon Heavy launch when no one is expecting it...

Might be x-37, they have more than one.

Not FH, because only one landing at LZ-1.

[TheEpicSquared]

EDIT: @Ultimate Steve, thought you would be interested. Do you think you can make it? If not I can ask a few questions for you, no problem  

Edited October 14, 2017 by TheEpicSquared

[Ultimate Steve]

39 minutes ago, TheEpicSquared said:

EDIT: @Ultimate Steve, thought you would be interested. Do you think you can make it? If not I can ask a few questions for you, no problem  

Thanks! I almost forgot. I should be ready-ish by then. In case I'm not, if you could ask about the possibility of recovering the ISS/Hubble/Space debris with the BFR that would be great!

[TheEpicSquared]

Just now, Ultimate Steve said:

Thanks! I almost forgot. I should be ready-ish by then. In case I'm not, if you could ask about the possibility of recovering the ISS/Hubble/Space debris with the BFR that would be great!

No problem  

[wumpus]

2 hours ago, PB666 said:

In both Texas and Minnesota during the Winter there is wind turbine production that exceeds demand and the price of wind powered electricity drops to zero.

I wonder just how long it would take to justify building an aluminum plant (or other chemical process where the standard procedure uses a lot of electricity).  From  a chemical production view, cracking water for hydrogen (and oxygen) is pretty silly and there are certainly plenty of other chemical processes that require electricity.  Aluminum is pretty obvious, the stuff is called "frozen electricity" for a reason.  Basically look at what chemicals are being produced near Niagara Falls and see what has low startup costs.

Also how much of Texas?  There are three grids in the US: East, West, and Texas.  I'm guessing it is too far to run a DC line (avoiding grid issues) to Louisiana and the chemical plants there.

No idea what this has to do with Spacex (Tesla bought Solar City, not Spacex).

[Ultimate Steve]

AMA is live! Unfortunately, it is in contest mode so he'll probably see everything equally, no point in upvoting things so they get seen.

EDIT: We're only 15 minutes in and the post has already been gilded three times...

EDIT 2: Four times at 16 minutes...

EDIT 3: Five gildings at 17 minutes.

Edited October 14, 2017 by Ultimate Steve

[StupidAndy]

I can also ask a question if anyone wants to too

should've said this about 3 days ago...but better late then never