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NewMars members are known for creative thinking.
Much of creative thinking is intended to stimulate discussion, with no intention of trying to match what is possible in the Real Universe.
Occasionally our members attempt creative thinking in expectation the Real Universe will approve.
This topic is available for members to consider ideas that appear to be impossible, but which look attractive if they were possible.
Post #3 of this topic will introduce an example.
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This post is reserved for an index to posts that may be contributed by NewMars members over time.
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Post #3: 240 Meter Heating Pipe for Propulsion
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In the topic "Mission Impossible", we have an entry from a small team working on solar powered propulsion...
The goal is to use solar power to propel a space vehicle using liquid hydrogen as the propellant.
Initial conditions are defined as:
Power to be collected: 40 megawatts
Flow rate of hydrogen: 2 kilograms per second (there is a 1 kilogram per second variant)
ISP to be achieved 800
Thrust: .5 (1/2) ton-force
(For reference, one ton-force is 9806.65 Newtons) (per Google)
Desired operating temperature: 3000 Kelvin
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In analysis of a possible configuration for such a vessel, the team has published a configuration that is 240 meters square.
The heating pipe would run down the center of this structure, which implies a length of 240 meters.
The heating pipe can be shorter.
The tradeoff is that optical fiber to deliver photons to the engine must be longer.
The consequence of the change is increased mass for optical fiber, and a bit more work at assembly time.
The mass for the heating pipe is correspondingly reduced.
A consideration is that heat must be removed from the material facing the heated hydrogen in the heating chamber.
Only 2 kilograms of hydrogen is available to cool the material of the heating chamber each second.
Conclusion: The Real Universe may prohibit this combination of requirements.
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