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I had forgotten about this topic created by Tom Kalbfus ...
Recently (in May of 2024) GW Johnson has reminded us of the value of isp greater that 450, in his analysis of SSTO with respect to the Rocket Equation.
I asked Google about isp greater than 450, and it popped up with metallic hydrogen.
It turns out Kalbfus and numerous other members including Mars_B4_Moon have been collecting links and text about this form of hydrogen.
As far as I know the form does not now and never has existed on Earth.
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This is a summary of a brief conversation with ChatGPT4o about metallic hydrogen ...
Metallic Hydrogen: Potential and Theoretical Insights
Introduction to Metallic Hydrogen
Metallic hydrogen is a phase of hydrogen where it behaves like an electrical conductor. This state is theorized to occur under extremely high pressures, similar to those found in the cores of gas giant planets such as Jupiter. The concept dates back to the 1930s.
Theoretical Basis for Metallic Hydrogen's Properties
High Pressure and Temperature: To create metallic hydrogen, pressures of several million atmospheres are needed. Laboratory experiments use diamond anvil cells to approach these conditions.
Superconductivity: Metallic hydrogen is expected to be a superconductor at room temperature, potentially revolutionizing energy transmission.
Energy Density: The energy density of metallic hydrogen is significantly higher than that of conventional rocket fuels.
ISP Estimate of 1700
The specific impulse (ISP) of 1700 seconds for metallic hydrogen is based on theoretical models of its properties:
Energy Release: The transition from metallic to molecular hydrogen releases a vast amount of energy, underpinning the high ISP estimate.
Theoretical Calculations: The ISP of 1700 seconds is derived from models considering energy density and phase transition efficiency.
Experimental Data and Challenges
Experimental Confirmation: Currently, there is no experimental confirmation of stable metallic hydrogen at lower pressures. Claims exist but are still under scrutiny.
Stability Issues: Maintaining metallic hydrogen in a stable form at lower pressures is a significant challenge.
Practical Use: Due to technical challenges in creating and storing metallic hydrogen, its use as rocket fuel remains impractical at present.
Conclusion
The ISP of 1700 for metallic hydrogen is a theoretical value based on its high energy density. While promising, it remains speculative pending experimental verification and technological breakthroughs. This topic offers exciting opportunities for creative thinking about future technological advancements.
Encouragement for Further Discussion
Focus on the theoretical aspects and potential breakthroughs needed to make metallic hydrogen a viable rocket fuel. Explore both the scientific challenges and transformative possibilities it presents.
The summary above does not include a hint I found, that a mixture of liquid and metallic hydrogen might have an isp of 900.
The summary DOES hint at the operational challenge of avoiding spontaneous reversion from metallic state to liquid or gaseous, with release of energy.
Update on Saturday 2024/06/01 ... I just re-read the topic from the top, and re-discovered the quality of the discussion.
The dangers of this material seem to outweigh it's potential benefits, but I'm glad researchers have been investigating and reporting on this phenomenon.
A post or two considered compressed Deuterium .... that might be worth a follow up, if anyone has time.
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