h a l f b a k e r yLike a magnifying lens, only with rocks.
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We have the tech to make a steam rocket but heating sources make it so that they can not compete against our current engines.
We also currently use mirror arrays to heat molten salt to extreme temperatures.
Can we not combine these two technologies in such a way that an adjustable solar array not
only pre-heats the water but tracks the rocket after launch and imparts energy to it from the ground?
We could take the weight of the previous heat source on board as added fuel or exchange it for payload.
Ground based lasers
https://en.wikipedi...ki/Laser_propulsion
[AwarmRay, Jun 09 2022]
LightCraft
https://science.how...ight-propulsion.htm
Also similar; does away with propellant as well. [neutrinos_shadow, Jun 09 2022]
[link]
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Interesting idea, but for the weight of that salt or
water, you can have stuff that has the potential
energy built in chemically no? |
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Just water as propellant. |
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As per [a1]'s link...
Two things;
Why ammonia? They don't explain. |
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And why have any solar collectors on the craft itself adding drag and redundancy when all power can be ground-based? |
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Preheating the propellant on board is a problem because it is so difficult to shed excess heat in a vacuum. Components will likely overheat and fail, including any passengers. |
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//Just water as propellant.// |
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What you're looking for here is phase change, liquid>gas,
because the gas wants to be in a much larger volume and so
that's what's generating the pressure under the craft. Water
is perhaps the worst of the more obvious choices because
it's phase change is ludicrously expensive in terms of
energy, water is a real oddball. It's 2256kJ/kg, vs say
ethanol at 800 & something. If you're trying to lose heat
energy, water is top of the list, but we're not, we want to
make pressure from energy, and in that regard, ammonia is
twice as good, and it has a boiling point (-33) that might be
more amenable to the task. |
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Cool. What are the environmental effects of releasing copious amounts of ammonia into the atmosphere as opposed to water vapour?
Water may suck as a propellant but if the ground based heat source is passive and solar then as much as water sucks the environmental impact and carbon footprint of such a rocket launch would be effectively zero other than the "contrail" and that should offset an absolutely huge amount of propellant suckitude when balanced against a rain of ammonia and laser power costs I would think. |
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I just like trying to reduce things down, to their might -have-been-possible thousands of years ago stage, so a steam rocket powered by a parabolic array might have been something oh say they might have been able to pull off in ancient Greece or Egypt. |
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I went from a homestead childhood to modern times without finishing highschool so that's kind of my zone. Ancient tech.
In a magical "someday" I will have freed up enough time to hire a tutor to rapidly catch me up on several whacks of things I was either denied or had to give up learning in order to survive and put myself in a place to be able to learn when I became mature enough to do so.
I had to choose and that's the choice I made. |
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I would very much like to learn the language of mathematics someday. |
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Atmospheric ammonia isn't uncommon, it's largely released
from agriculture. Cow, chicken and pig shit mostly. It exists in
the atmosphere in a dynamic equilibrium with plant growth.
Essentially, it's used by plants if it's high enough concentration. |
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