Talk:RECYCLING ROCKET EXHAUST

     I need help with the style conventions of Lunarpedia.  I am out of practice in contributing for Lunarpedia and if someone could tell me what is needed to meet the ordinary style expected, I would appreciate that.  
     For the recycling of rocket exhaust from a rocket launched through a tube there would be some difficulty is testing the concept on Earth.  To prevent damage to the wall of the tube at the launch of the rocket, the rocket could be launched from a mobile launch platform accelerated in much the same way that fighter aircraft are accelerated.  This could give the rocket a velocity of 67 meters per second at the time of launch thus spreading the erosive effect of the exhaust out over a larger area of the tube wall.  This would also provide the ullage thrust necessary for the bubble in the fuel tank to be toward the front of the rocket and the fuel to be next to the fuel pump inlet.  Also it provides the first 4 percent of mission delta v.  However this does not work in reverse with the rocket decelerating to a stop and landing in a tube as would be necessary if one were performing a test on Earth and wanted to preserve the test rocket for another run.  
     The use of a larger tube for the tube landing area in the model test with T intersecting tube sections allowing the exhaust to dissipate into a larger area might serve the purpose of a model test or the purpose of an operational variant for which it is necessary to eject orbit bound cargo immediately after the rocket exits the acceleration tube with the rocket proceeding to a deceleration tube.  

Farred (talk) 01:14, 11 April 2022 (BST)

Some figures for a 1500 kilogram cargo rocket burning methane and oxygen, launched

4839 kilograms launch weight of tube launched rocket

2371 kilograms propellant (fuel & oxygen)

968 kilograms empty weight

1500 kilograms cargo

Vsub f = Vsub exh * (ln [Msub i/Msub f)

1680 meters per sec = 2500 meters per sec * (0.672)

exp (0.672) = 1.958 ############# ln (1.958) = 0.672

Msub f/Msub i = 51 percent.

51 percent final weight - 20 percent engines, structure and controls = 31 percent cargo

1500 kilograms cargo / 0.31 = 4839 kilograms initial mass

Farred (talk) 22:17, 28 June 2022 (BST)

Nice to see new work here! You need to divide the text into chapters and sub paragraphs. A long list of bullets is hard to read. Please keep consistent units, you switch from metric to US units. Just stick to metric.

If you are building a tube, why not just use magnetic acceleration? All fuel on the Moon needs to be manufactured. In a sense, fuel is just an energy storage medium. So when you use fuel to propel a rocket, instead of a magnetic launcher, you are replacing storing energy in a magnetic ring, or capacitors, with energy stored in a chemical form.

There are at least four problems with this: -The production of the fuel is not efficient compared to the direct storage of electrical energy. -The rocket is transporting the fuel, so energy is lost due to the rocket equation. You are accelerating fuel that will not be going anywhere. -The burned fuel, now in the form of water and CO2, will be hot. You need to cool it and that wastes energy. -It will take time to cool the exhaust and empty the tube to recycle it. this reduces the output significantly, compared to something like a magnetic launcher than can launch much faster. In theory.

Although I don't think the overall concept works (sorry about that) you would improve it by using oxygen and hydrogen. The only product is water and that is much more easy to condense than CO2.