New Mars Forums

tahanson43206

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Registered: 2018-04-27

Posts: 19,383

Tutorial on the Nature of Heat as Applied to a Heat Shield

With a word of appreciation for the example of JoshNH4H, I am offering this topic for a review of our (human) understanding of the nature of heat at the quantum level, with the goal and intention of reviewing what is known in order to solve or at least address problems of the present day.

This is intended to be a topic that can be read from the top, and my hope is that each post will contribute in an orderly way to the development of the theme.

In order to provide a way for present and future members to contribute, I am setting up a companion topic, where suggestions, ideas, comments and corrections may be (and hopefully will be) posted.

I'd like to open with a compare and contrast scenario:

A baseball whacked by a stout player is traveling at a respectable velocity over the turf.  It reaches the mitt of a fielder.  The mitt (and the fielder) absorb the energy of the baseball, and the baseball becomes embedded in the web of the mitt, until it acquires the velocity of the mitt, and eventually the velocity of the fielder.

In contrast, a molecule of Carbon Dioxide is minding its business bouncing gently around with it's neighbors in the atmosphere of Mars, until it is rudely approached by an advancing human space craft heat shield.   Unlike in the example of the mitt, the spacecraft rude and somewhat vigorously encounters the electron shells of the CO2 molecule, by presenting the electron shells of its external surface to the CO2 molecule.

In the encounter, the CO2 molecule may be regarded as a purely elastic ball, which is free to travel in any direction, while the shield molecule is bound to its neighbors by electron bonds generically called "cohesion" .

In the case of the British Skylon experimental aircraft, there is an attempt in progress to try to accelerate the molecules of atmosphere to near to the velocity of the craft without creating heat (rebounding actions) by cooling the arriving molecules with liquid hydrogen.

(th)

tahanson43206

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Registered: 2018-04-27

Posts: 19,383

Re: Tutorial on the Nature of Heat as Applied to a Heat Shield

For GW Johnson re #221

Thank you for your continued interest in this topic!  I have started an investigation of the nature of quantum level interactions between gas particles and solid (bound by cohesive electron bonds) matter.  I've been too busy with other interests/duties to pursue it, but it is there waiting for someone to invest the time that will be needed.

The object of ** that ** topic is to try to understand (a) why elastic particles (molecules) bounce away from solid molecules instead of sticking to them, (b) to try to imagine a way to capture them.  It ** is ** intuitively obvious that since electrons repel each other, electron shells of atoms would repel each other, unless an atom has enough momentum to overcome the objections of the electron shells and penetrate far enough to dislodge the target atom from the matrix of which it is apart, as happens when solid material (ie, heatshield) is exposed to gas molecules at sufficiently high speed.

The Skylon approach ** appears ** to be to cool the metal of the funnel collecting gases so the arriving molecules do not dislodge the metal and (b) to absorb energy from the elastic molecules as they bounce around frantically in the confines of the tunnel where they are being collected.

The ** ideal ** situation (possibly not available in the ** real ** Universe) is for the gas molecules to quietly accept capture by the arriving heat shield, to accept acceleration to the velocity of the heat shield without frantically trying to escape, and to contribute to the momentum of the heatshield vehicle by decreasing that momentum by the amount of the mass of the molecule.

To my knowledge there is ** no ** way to achieve that ideal, but I think the topic is worth exploring.

If the ideal could be achieved, then the molecules in the path of the vehicle would pile up in front of it in an accumulating stack until the vehicle releases them, at which point they would have a velocity lower than was the case when the descending vehicle first showed up.

(th)

tahanson43206

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Registered: 2018-04-27

Posts: 19,383

Re: Tutorial on the Nature of Heat as Applied to a Heat Shield

This topic is inspired by the work of Eric Drexler, when he was a student at MIT.

I had the opportunity to meet Eric Drexler in connection with activities of the L5 Society,  His wife, Chris Peterson, was an officer of the Society at the time.

My copy of "Engines of Creation" is buried in moving boxes, but I was delighted to find a pdf of the text is available:

https://www.nanowerk.com/nanotechnology … port47.pdf

The forward is by Marvin Minsky

Engines of Creation
is the best attempt so far to prepare us to think of what
we might become, should we persist in making new
technologies.
MARVIN MINSKY
Donner Professor of Science
Massachusetts Institute of Technology

A ** lot ** of time has passed since the book was published, and many folks have participated in advancing the State of the Art of Nanotechnology.

K. Eric Drexler - Wikipedia
en.wikipedia.org › wiki › K._Eric_Drexler
His 1991 doctoral thesis at Massachusetts Institute of Technology was revised and published as the book Nanosystems: Molecular Machinery Manufacturing and ... Life and work · Reception · Works  Doctoral advisor: Marvin Minsky Thesis: Molecular Machinery and Manufacturing With Applications to Computation (1991) Fields: Engineering, molecular nanotechnology Born: April 25, 1955 (age 65); Alameda, California, U.S

The vision I have for this topic is to discover a way to capture molecules of gas, accelerate them to the velocity of a spacecraft, and store them in a compartment for later use.

The mechanism, if it comes to pass, will be the province of nanotechnology.

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tahanson43206

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Registered: 2018-04-27

Posts: 19,383

Re: Tutorial on the Nature of Heat as Applied to a Heat Shield

It's time for an update to this topic ... the report below is about work done at NASA, despite funding challenges and Covid delays, to improve performance of heat shields, especially for heavier payloads...

https://www.yahoo.com/news/nasa-unveils … 00402.html

If anyone can find details on how this shield differs from others, please post !!!

NASA unveils heat shield that could help with landings on Earth and Mars

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NASA unveils heat shield that could help with landings on Earth and Mars
ROBYN BECK/AFP via Getty Images

Noble Brigham, The Virginian-Pilot
Wed, June 15, 2022, 7:58 PM
In an almost entirely windowless metal building on the campus of NASA’s Langley Research Center in Hampton sits the black, dome-shaped culmination of a $93 million project.

It’s a heat shield, about 20 feet in diameter, that one day could help to land cargo and crew missions on Mars or anywhere else that has an atmosphere. Its purpose is to create drag and slow a space vehicle for reentry. It could also have commercial uses, like allowing for engines sent into space to be retrieved from space and reused, and bringing items back that have been manufactured in space, said Barb Egan, program manager at United Launch Alliance, a corporate partner of NASA.

Wednesday afternoon, NASA officials gave the public a glimpse of the space travel technology that is the latest in a long line of heat shields, and larger than any of its predecessors, which allows it to carry heavier loads at greater altitudes. That’s important because to sustain human life on Mars, astronauts need to be able to put 20 to 40 metric tons of cargo on the planet’s surface, said Joe Del Corso, the project manager.

In November, the shield will be tested in a launch from Vandenberg Space Force Base in California. It’s riding along with a United Launch Alliance weather satellite and will then land in the ocean off the coast of Hawaii where researchers will recover the hardware — if they can find it, said Trudy Kortes, director of technology demonstrations for the Space Technology Mission Directorate, which develops tech for missions.

She said the heat shield could be used in a mission to Mars in the mid-2030s.

Del Corso said a volcano diver sponsored by National Geographic has already approached them about using it for a jump from space. “We said this isn’t the right technology yet. I’m not going to risk somebody’s life yet,” he said.

The upcoming test launch has personal significance for the people who have worked on the project because it’s named in honor of Bernard Kutter, the manager of advanced programs at ULA, who died in 2020. Egan said he was passionate about low cost access to space and new technologies.

A container of his ashes will be launched with the heat shield, said Del Corso, who described Kutter as a “great engineer.” The ashes will return with the reentry vehicle so they can be given back to his family.

The project has gone through challenges, including funding constraints, a government shutdown delay and the pandemic, which temporarily forced everyone off the Langley property, said Del Corso, but those involved are excited about its potential.

Clayton Turner, the director of the research center, said it’s “not a piece of hardware, but a path to a new future.”

Noble Brigham, noble.brigham@virginiamedia.com

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SpaceNut

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From: New Hampshire

Registered: 2004-07-22

Posts: 29,431

Re: Tutorial on the Nature of Heat as Applied to a Heat Shield

Other than the size we need to know more than that to determine what has been checked in the ability to land on mars. GW and others know that its part material to mass as well as shape to give it lift. Then there is the question of disposable or reusable to that equation.

tahanson43206

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Registered: 2018-04-27

Posts: 19,383

Re: Tutorial on the Nature of Heat as Applied to a Heat Shield

In another topic, quite recently (January of 2023) GW Johnson posted a reminder about the ability of the glass fiber bricks used on the Space Shuttle, to protect the vulnerable aluminum skin of the shuttle from the searing heat of re-entry.

Dr. Johnson reminded us that it was the ** voids ** inside the brick that kept the heat away from the Shuttle skin.

I'd like to offer an alternative/supportive interpretation of the physics of the glass bricks ....

At this point, I don't think there is any evidence one way or another, so this alternative is offered for everyone to beat on with sticks, or a club if that is appropriate.

The "voids" cited by GW Johnson ** may ** have performed a molecule taming function I've described elsewhere.

A molecule of ordinary matter is a perfectly elastic entity.  The forces at the exterior of every molecule are electric.

When two molecules interact with each other, if the collision is insufficient to cause the two to merge, then they rebound from each other with perfect efficiency.

However, in changing direction, atoms/molecules emit radiation.

The radiation produced by undisciplined bouncing in the vicinity of a solid object travelling through a gas is perceived by an observer as heat or light or both.

Here is the essence of my guess about the voids in the glass tiles .... they ** may ** have constrained the otherwise undisciplined bouncing of the air molecules.

If this theory is correct, then a test would be to reduce the size of the voids, to further constrain the otherwise undisciplined bouncing of the air molecules.

It should be possible for a suitably well equipped laboratory to investigate this theory.

(th)