Focused Solar Power Propulsion

tahanson43206 · 2025-03-11 17:39:15

Among the vendors suggested by Gemini was Edmund. I am among the thousands if not millions of folks who bought products from Edmund Scientific. The Wikipedia page on that company sure brought back memories. The company still exists in a sense, because while it has changed names a bit and changed owners along the line, the services it provided from the beginning still appear to be it's focus.

Here is a copy of an email I sent to their Tech Support contact address:

Hello!
Gemini (Google's enhanced search engine) came up with your name when I asked for help finding a vendor.
I'm a (Junor) moderator for the NewMars.com/forums, which is a subsidiary of the Mars Society, James Burk Executive Director.
The forum has been operating for over 20 years, and it has over 1000 registered members, although only a few are active on a daily or weekly basis.
In my role I seek to provide support for our members when they offer interesting ideas.
In this case, we have a member who is interested in thinking through how to enlist sunlight to propel a space vehicle more effectively than is possible today using photocells that propel ions.
Our member's idea is to use thermal energy in a way that is similar to the NERVA nuclear rocket.
The difference is that while the NERVA system used fission to produce thermal energy to accelerate liquid hydrogen, our member's design would use solar energy to do the same thing.
In contacting you via this contact email, I am inviting your support to help us think through the optics. We have others in the membership with expertise in propulsion. I am attempting to help our member to find a set of products that exist today that could be assembled on orbit to produce 40 megawatts of thermal energy.
The specific need is for a TIR lens that can collect photons from a surface of 10 square centimeters and deliver them efficiently to a standard optical fiber used for communications. We understand that a standard communications fiber can handle a watt of energy without overheating, so the TIR lense is sized to collect a watt from the Sun if flown at a distance where insolation is 1000 watts per square meter. A lens that would have that area would have a diameter of 36 mm, and I see a number of lens offerings in the marketplace of that size.
The dilemma I am facing is the delivery to that optical fiber.
By any chance, are you aware of a TIR device that can perform the required function?
The gent who is leading this inquiry would like to collect 40 MW for his heat engine, and an array to perform that service would be 460 meters on a side. The individual one watt collectors would be 36 mm in diameter, and we would need 40,000,000 of them.
A propulsion system developed along these lines should last for centuries, since there are no parts to wear out. Radiation will be beating on the system incessantly, so it may degrade, but the rate of deterioration is outside the scope of our ability to estimate.
Just FYI... this question and all correspondence you may decide to provide will be published without editing on the NewMars.com/Forums site, in a Category called Interplanetary Transportation and a Topic called Focused Solar Power Propulsion.
Thanks very much for your time!
tahanson43206 (Junior moderator)
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tahanson43206 · 2025-03-11 18:04:46

I am please to report that a member of the staff of Edmund Optics replied to my inquiry.

Hello Tom,
Thank you for contacting Edmund Optics product and application support. I am personally reviewing your inquiry and will be responding as soon as possible. If your inquiry requires immediate response, come chat with us at www.edmundoptics.com or call us at 800-363-1992. Alternatively, we do offer a vast amount of technical content in our Knowledge Center which may be of assistance in the meantime. I look forward to speaking with you!
Best regards,
–————————————————
Simon Field | Product Support Engineer
Edmund Optics® Tucson
THEFUTUREDEPENDS ON OPTICS™

I'll report any further correspondence as it may arrive.

Members are welcome to add questions they may have, or to offer suggestions for finding vendors for this specific application.

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tahanson43206 · 2025-03-12 07:04:40

This is a follow up to Post #27...

At the Edmund Optics site I clicked on the Optics button and got this:

Optical Lenses
Optical Lenses are optical components designed to focus or diverge light.
Optical Lenses, which may consist of a single or multiple elements, are used in a wide variety of applications from microscopy to laser processing.
Many industries utilize Optical Lenses, including life sciences, imaging, industrial, or defense.
As light passes through a lens, it is affected by the lens’ profile or substrate. A Plano-Convex (PCX) or Double-Convex (DCX) lens causes light to focus to a point, while a Plano-Concave (PCV) or Double-Concave (DCV) lens causes the light traveling through the lens to diverge.
Achromatic Lenses are ideal for applications requiring color correction, while Aspheric Lenses are designed to correct spherical aberration.
Germanium (Ge), Silicon (Si), or Zinc Selenide (ZnSe) lenses are ideal for transmitting the Infrared (IR) spectrum, while Fused Silica is well suited for the Ultraviolet (UV).
Edmund Optics offers the world’s largest inventory of off-the-shelf optical components, which includes an extensive selection of stock optical lenses such as Achromatic Lenses or Aspheric Lenses. Many of Edmund Optics’ lenses are offered with a variety of coating options for the Ultraviolet (UV), visible, or Infrared (IR) spectrums.

There a number of images of various optical devices below the text.

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tahanson43206 · 2025-03-20 08:26:24

Our inquiry of Edmund Optics was initiated March 12th.

We have not heard back, but a reply is certainly possible. It is my impression Edmund is a distributor and not a manufacturer, so they might have had to contact a manufacturer to see if our request is possible.

In the mean time, I asked Google to look for manufacturers of TIR devices:

If you're looking for manufacturers of Total Internal Reflection (TIR) optical devices, consider Shanghai Optics, Dialight, and Thorlabs, known for their TIR lenses, optics, and prisms.
Here's a more detailed breakdown of some TIR optical device manufacturers:
Key Manufacturers:
Shanghai Optics:
Specializes in custom optical engineering solutions, including TIR lenses, and offers a wide range of optical components and systems.
They offer custom lens design and assembly, as well as manufacturing services.
They also produce precision optical components for medical device development and optical systems for medical and life sciences applications.
Dialight:
Known for their TIR optics designed for optical efficiency with various high-power LEDs.
They offer a variety of industry-leading optics for LED lighting applications.
Thorlabs:
Provides a range of TIR retroreflector prisms, including uncoated and AR-coated versions.
They offer retroreflectors that rely on total internal reflection, as well as backside-coated retroreflectors.
Other notable manufacturers:
Fusion Optix: Offers linear TIR optics.
Young Optics: Provides total internal reflection (TIR) prisms.
PFG Optics: An optical prism manufacturer in the USA, offering right-angle prisms, spectra precision prisms, and more.
Brightlx Optical Ltd: Specializes in providing tailored LED optical solutions, including TIR lenses.
Lumenflow: Offers optical silicone injection molding for TIR lenses.
WTS Photonics: An optical lenses factory and supplier of optical windows, lenses, and prisms.
PreciSe Hyper iMage Optics (Suzhou) Co., Ltd (PHYO): Specializes in optical components, including TIR prisms for DLP projection.
TIR Lens - Shanghai Optics
Shanghai Optics produces high quality TIR lenses suitable for a wide variety of different purposes.
Shanghai Optics
TIR Optics - Dialight Signals & Components
Optics - TIR Optics - Dialight Signals & Components.
dialightsignalsandcomponents.com
Medical Device Optics
At Shanghai Optics, we manufacture precision optical components for medical device development as well as a wide range of optical...
Shanghai Optics
https://www.shanghai-optics.com › components › tir-lens
TIR lenses collimates light using total internal reflection. Shanghai Optics manufactures high-quality TIR lenses for various applications.
Dialight Total Internal Reflection (TIR) Optics
Mouser Electronics
https://www.mouser.com › new › dialight-tir-optics
Feb 23, 2024 — Dialight Total Internal Reflection (TIR) Optics are designed for optical efficiency with a variety of today's standard high-power LEDs.

As a reminder, we are working an idea of kbd512, to collect photons from the Sun in a plane, instead of using mirrors. A plane is much easier to build and to maintain than a complex mirror would be, and most importantly, a plane can endure forces that a space vessel will experience.

The key concept that kbd512 brought to the vision is use of TIR devices to collect photons and feed them into optical fiber. This technology is in use in architecture today, to bring solar illumination into interior spaces, when windows are impractical.

However, it is possible that TIR devices in existence today are not a perfect match for the space vessel application.

In case a NewMars member (or one of our readers) is interested in helping to find a supplier, the specifications are:

Circular diameter 36 mm (to provide a total area > 10 square centimeters) and output to a single optical fiber (communications grade).

It is our understanding that a standard communications grade optical fiber can accept 1 watt of photon flow without overheating, so the TIR device is sized to deliver 1 watt given solar insolation of 1000 watts per square meter.

The application in study would require 40,000,000 of these devices, to collect and deliver 40 MW to the propulsion subsystem.

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tahanson43206 · 2025-03-20 11:12:04

This post is about maintenance....

The Optical Plane Deep Space vessel in discussion in March of 2025 will need maintenance.

The optical collection system itself should last for many years, but the heat transfer system is going to be operating at temperatures and pressures that are at the upper limits of what known materials can handle.

This post is intended to open discussion for maintenance of the heating system.

The current design includes two "wings" of 240 meters by 120 meters on either side of the propulsion subsystem.

The propulsion subsystem is 240 meters long, and it includes ports for admission of photons from the wings.

The core of the heating system is a structure designed to absorb photons and to heat hydrogen gas via direct contact (conduction) and convection within the gas stream.

If the vessel is designed so that the wings can be separated from the heat pipe subsystem, that would facilitate replacement of quartz ports if that becomes necessary.

Those quartz ports are going to be facing hot gas far above the melting point of quartz, so the current thinking is to cool them with hydrogen as it flows from storage tanks to the intake ports of the heating system.

In addition, the heat fins on the central core may deteriorate due to the temperature and pressure, and the active nature of hydrogen.

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tahanson43206 · 2025-03-20 11:37:39

This post is reserved for a set of drawings prepared by GW Johnson in support of the Optical Plane Deep Space vessel discussion.

Image 1

Image 2

Image 3

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tahanson43206 · 2025-03-21 11:52:10

This post includes a drawing prepared by GW Johnson to study a segmented heating chamber for the Optical Plane Deep Space vessel as it is being imagined in early 2025.

The issues/challenges to be addressed include:

How to build the heating chamber on Earth so it can be assembled and used in space.

There are a number of tradeoffs in play, in this situation. The amount of LH2 suggested is only 2 Kg per second. That seems low compared to the size of the heating tube of 240 meters.

The reason for the 240 meter length was to keep fiber feed lines short. There may be a shorter length for the heat engine that works better to balance the supply of energy, the supply of LH2, and the capabilities of the materials.

How to assemble the structure, which is currently envisioned as 240 meters long.

This challenge would be less severe if the heating tube is shorter.

How to operate the system so that the Quartz windows do not melt as the system operates.

LH2 cooling seems the best solution in March of 2025, but perhaps additional/alternative cooling is possible.

How to maintain the system as components reach retirement age.

Segments would appear to be a way to facilitate both construction and maintenance, but then how to deal with joints is a concern. The operating temperatures and pressures of this system are at the upper limits of human capability.

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tahanson43206 · 2025-03-24 13:26:50

One of the outcomes of the Google Meeting on Sunday March 23, 2025, was use of the terms for heat transfer.

It turns out all three are involved in this project. Google offers this summary:

Search Labs | AI Overview
Learn more
Heat Transfer Vocabulary | Word Wall & Quiz | Conduction Convection Radiation
Yes, "conduction" and "convection" are indeed terms used to describe the transfer of thermal energy, along with radiation, which are the three main ways heat can move.
Here's a more detailed explanation:
Conduction:
This refers to the transfer of heat through direct contact, where heat energy moves from one object to another (or within a substance) when they are in contact.
Example: Touching a hot stove burner and feeling the heat.
Mechanism: Heat energy is transferred through collisions between molecules.
Convection:
This involves the transfer of heat by the movement of fluids (liquids or gases).
Example: Boiling water, where hot water rises and cooler water sinks, creating a convection current.
Mechanism: As fluids heat up, they become less dense and rise, while cooler, denser fluids sink, creating a circular motion that transfers heat.
Radiation:
This is the transfer of heat energy through electromagnetic waves, which can travel through a vacuum (empty space).
Example: The heat you feel from the sun or a campfire.
Mechanism: Electromagnetic waves carry energy that can be absorbed by objects, causing them to heat up.

Radiation is how energy is transferred from outside the heating chamber to a surface on or in the chamber.

Conduction is the process by which energy is transferred from a hot solid to gas molecules.

Convection is the process by which energy is transferred from one gas molecule to another.

Thus, in the proposed solar powered propulsion system, all three are involved in exactly equal measure, since the same energy has to be applied in all three modes, to achieve the desired result, which is hot gas exiting the heating chamber.

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tahanson43206 · 2025-03-24 17:23:41

This post is reserved for new drawings created by GW Johnson in support of an initiative by kbd512.

Study of two alternative heating core designs.

Please note that these studies do NOT include analysis of force flow through the body of the engine to the frame of the vessel.

Coupling of the engine to the vessel will happen at some point. At this point we are evaluating options for delivery of solar energy to the engine.

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tahanson43206 · 2025-03-26 07:23:13

Sketch of Engine cross section following Google meeting Sunday 2025/03/23

This sketch attempts to capture the state of play as tradeoffs war with each other to arrive at an optimum solution.

The problem to be solved is simple enough: Propel a space vessel using solar power...

The technology required is at the limits of human capability in 2025.

The materials must withstand temperatures on the order of 3000 Kelvin, pressures sufficient to deliver 5000 Newtons ( 1/2 force ton) of thrust, and have the strength to deliver that force to cold frame of the space vessel.

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tahanson43206 · 2025-03-26 18:38:27

This post is about delivery of photons to a heat engine if there are 40,000,000 feeds of 1 watt each.

If we assume the photon delivery surface is a cylinder of radius 1 meter, then the height of that cylinder would be a little over 5 meters.

Right cylinder
Solve for height
h≈5.37m
h=5.3662m
Surface area of cylinder is 40 square meters.
Radius of cylinder is 1 meter

The area of 40 square meters derives from the number of feeds, and assuming one square millimeter per feed.

A cylinder feeding photons into a heat engine would be 5.37 meters high, so the hot portion of the engine would be at least 5.37 meters long.

The engine would include a nozzle assembly at the stern, and a cap designed to deliver thrust to the spacecraft from the top of the heat engine.

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tahanson43206 · 2025-03-27 09:22:25

The sketch below shows the evolving vision for the Optical Plane Space Vessel as guidance arrives from team participants.

The drawing is of a conceptual nature. The wings can be any shape that contains the area of a square 240 meters on a side.

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kbd512 · 2025-03-27 17:05:18

I was looking for an image that aptly illustrates what I meant during our last meeting about using fiber optic rods / bundles with a small "stand-off", pointing their optical power at the rocket engine core. I think I've found something that illustrates what I'm talking about:

plasma-compression-prototype-(General-Fusion).jpg

8168465707e799941fa50f820daf0305

Imagine for a moment that all those rods you see pointed at the core of that fusion reactor were instead fiber optic cables, and that there's a short / small "stand-off" between where the fiber optic cable terminates and where the outer wall of the core begins. Further imagine that the core is some kind of pure Carbon, because Carbon is one of the few materials capable of withstanding the megawatts of power being directed at it.

Examples of Carbon or Carbon Fiber / Ceramic Matrix Rocket Engines and Nozzles:

This one was printed in Copper, but the implications of AI-designed rocket engines for efficient thermal power transfer are pretty clear:

kbd512 · 2025-03-27 17:17:22

I believe I've posted something like this before, but here's another paper from NASA on advanced Carbon / Carbon-Ceramic rocket engine main combustion chamber and nozzle design work going on at NASA:

Extreme-Temperature Carbon- and Ceramic-Matrix Composite Nozzle Extensions for Liquid Rocket Engines

Materials under development by MSFC and its industry partners have the potential to operate at temperatures up to (or above) 4250°F (2343°C).

2,343C is equal to 2,616.15K, so not quite where we need to be, but much closer than most metals. To be clear, UHTCs (Ultra-High Temperature Ceramics) are required to make this work at 3,200K, our target chamber temperature for 1,000s of Isp using pure LH2 propellant.

Carbon-Carbon Nozzle Extension Development in Support of In-Space and Upper-Stage Liquid Rocket Engines

They tested these nozzles with LOX/RP1, LOX/LCH4, and LOX/LH2 propellants. The entire point behind development of this tech is that the major parts of the engine are much lighter than Copper-Nickel alloys, Carbon is easier to come by than Copper and Nickel, they're not regeneratively-cooled, they're 3D printed so they cost less, and they're reusable.

Edit:
For comparison purposes, the 3,200K / 2,926.85C chamber temperature required to achieve 1,000s of Isp is most similar to the flame temperature created when MAPP gas is combusted with pure O2. Pure O2/H2 flame temperature is around 2,660C, and pure O2/CH4 flame temperature is around 2,810C.

Last edited by kbd512 (2025-03-27 17:33:35)

tahanson43206 · 2025-03-27 20:58:49

For kbd512 re #38 and #39

Thank you for these interesting and helpful examples, and for links to NASA research.

To assist any readers who may be trying to follow this discussion, GW Johnson recommends that the power take-off for this system is the nozzle assembly including the expansion bell. This subsystem can be made of material different from the chamber where heating is to take place. The nozzle and expansion bell are in need of cooling, because the nozzle assembly is going to bear the full load of thrust to be transferred to the vessel.

We have yet to decide how hydrogen is going to be admitted to the heating chamber.

We have yet to decide if any thrust is to be communicated to the vessel via the walls of the heating chamber. GW Johnson suggests that the entire thrust load can be carried by the nozzle assembly, provided that it is (a) strong enough and (b) kept cool.

In the conversation with ChatGPT4o below, I have inquired about the only existing example of what we are trying to do: mirror heated towers to generate electricity.

Solar Mirror Example and Carnot Clarification
Introduction:
The discussion begins with an analysis of the Gemasolar Thermosolar Plant, which uses mirror fields to direct sunlight toward a central receiver where thermal energy is collected and converted to electricity. The purpose of this comparison is to better understand the material and energy transfer processes relevant to our thermal propulsion project.
The Gemasolar Example
Materials Used: High-temperature alloys, ceramic materials, and other materials designed to withstand high temperatures and corrosion are employed in the solar receiver.
Heat Transfer Fluid (HTF): The most common HTF is a molten salt mixture of sodium nitrate and potassium nitrate, capable of operating at temperatures up to 600°C. Synthetic oils are used in some cases, but they are less thermally stable than molten salts.
System Efficiency: The overall efficiency of Gemasolar is approximately 20%. This means that of the total solar energy collected by the mirrors, only about 20% is converted into usable electricity.
Energy Losses: About 80% of the collected energy is lost due to thermal losses and inefficiencies in the power conversion cycle.
Total Collected Solar Power: For a net electrical output of 19.9 MW, the total solar energy collected is approximately 99.5 MW.
Clarification of the Carnot Limit
The discussion then turned to the question of whether Carnot efficiency applies to our thermal propulsion system. Here are the findings:
Applicability of Carnot Efficiency: Carnot efficiency applies only when thermal energy is converted to mechanical work or electricity.
Why It Doesn't Apply: Our design intends to directly heat hydrogen gas with photons, rather than converting thermal energy to mechanical or electrical energy. Therefore, the Carnot limit does not apply.
Energy Transfer Efficiency: The key concerns are thermal transfer efficiency, absorption efficiency, and minimizing radiative and convective losses.
40 MW Goal: If the entire 40 MW of collected solar energy can be effectively transferred to the hydrogen gas, this would represent an ideal scenario. In practice, some losses will occur, but not due to the Carnot limit.
Conclusion
In conclusion, while the Gemasolar Thermosolar Plant provides a useful point of comparison for energy collection and transfer, our system differs significantly because it does not involve the conversion of thermal energy to mechanical work. Therefore, the efficiency considerations focus on absorption, thermal transfer, and loss minimization rather than Carnot efficiency.
Would you like me to proceed by estimating the actual energy transfer efficiency achievable with the materials and designs we discussed?

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GW Johnson · 2025-03-27 21:30:21

The nozzle needs cooling because the most practical materials to build it are metals, and none of those survive 3000 K temperatures. The carbon-based chamber material can survive 3000 K temperatures, and if it has the strength to contain 5-atm-class pressures at such temperatures, then it needs no cooling.

Thermal expansion is going to be a real bugaboo with such a design, if you try to affix the engine to the vehicle at more than one axial station. I wouldn't do that myself, but I would make the mounting point and hardware very strong and stiff, so as to maintain firm control over the thrust vector direction line passing through the vehicle cg, no matter what thermal expansion occurs.

There is a downside and a work-around: firm mounting precludes easy gimbal-type thrust vectoring! You will need some other form of attitude control.

I would suggest attitude control thrusters. You can tap some hydrogen off the main chamber to run them, up nearer the cooler front end,
so the not-so-hot gas is easier to handle with metal tubing and valves.

Attitude thrusters are how we had positive flight control on the 4-stage solid-propellant "Scout" launcher without trying to do flexible-structure vectorable nozzles on the solid motors! Those were very simple, very lightweight hydrogen peroxide monopropellant decomposition thrusters. Electrically-heated catalyst beds in the thruster chambers. This required high-test peroxide, but the storage time before use was short enough to avoid that danger.

Trying to do vectorable nozzles on solid motors was very expensive, usually way too heavy in small sizes, and added multiple possible leak failure modes to the design. Only the strategic-size motors had them. They are usually hydraulically actuated, requiring both substantial motive power and some very heavy equipment to run them.

GW

Last edited by GW Johnson (2025-03-27 21:38:40)

tahanson43206 · Yesterday 09:26:29

Google found numerous citations for the Apollo Command and Service Module.

Here is a snippet from one:

The exhaust nozzle engine bell measured 152.82 inches (Template:Convert/round m) long and 98.48 inches (Template:Convert/round m) wide at the base. It was mounted on two gimbals to keep the thrust vector aligned with the spacecraft's center of mass during SPS firings. The combustion chamber and pressurant tanks were housed in the central tunnel.

https://nasa.fandom.com/wiki/Apollo_Com … ion_System

It seems to me that the need to keep the thrust aligned with the center of mass would be a requirement for the Optical Plane Solar Powered vessel as well, and that leads to the question of how gimbals could be designed for the high thrust expected from this engine?

Update for GW Johnson: Is it feasible to gimbal the entire engine compartment, as an alternative to tradition engine gimbals?

Update from GW Johnson via email: Yes. It is possible to gimbal the entire engine compartment.

Making this design change would simplify design of the rigid structures needed to transfer power from the exhaust port and expansion bell assembly.

It would ** also ** have the benefit of reducing flexing of the fluid feed at the top of the hot bulb. The flexing would still occur, but outside the hot engine compartment. The propellant is coming from the vessel ahead of the engine compartment. It needs to cool the exit port and expansion bell, and then (somehow) makes it's way up to the top of the hot bulb.

Detail: The propellant feed line at the top of the hot bulb needs to be flexible in the linear direction, since the hot bulb is going to expand as it is heated.

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kbd512 · Today 01:15:19

Keeping the main engine structure rigid is a good way to increase reliability / durability, as well as to decrease complexity and therefore cost / risk. Some of the optical power can be diverted to smaller thrusters to provide equally high-Isp maneuvering thrust from other fixed axis engines. My preference would be to use a small amount of optical power to provide propellant feed pressurization as well. Since the propellant is Hydrogen, fewer joints and separate components reduce the number of leak paths. Tungsten melts at 3,695K, so if we absolutely have to make the engine from metal, it could be made from a Tungsten alloy or Tungsten-based cermet. That said, UHTCs have higher melting points than Tungsten, 4,231K in the case of Hafnium Carbide, and better resistance to Hydrogen. Hafnium Carbide has very pedestrian oxidation resistance, meaning it begins to oxidize at temperatures as low as 430C, but it just so happens to withstand hot and high pressure Hydrogen particularly well. Similarly, pure Carbon can withstand hot Hydrogen fairly well. You can get superlative oxidation or reduction resistance from specific materials, but not both at the same time.

Erosion of refractory carbides in high-temperature hydrogen from ab initio computations

Abstract:
Advanced concepts for in-space propulsion require coatings that are resistant to erosion in high temperature and pressure hydrogen. The erosion of refractory carbides of interest for this application (ZrC, NbC, HfC, and TaC) is investigated using combined ab initio thermodynamic computations and equilibrium product analyses. The carbides are shown to erode through a combination of four governing reactions, the relative extent of which depend on environmental conditions. The product profiles from these reactions are complex but exhibit lower hydrogen saturation at higher temperatures and lower pressures. A metric is derived to determine the applicability of equilibrium analyses for erosion rates, based on experimental conditions. Heritage mass loss experiments on ZrC in hydrogen satisfy the equilibrium criteria, and, correspondingly, the computed equilibrium erosion rate agrees quantitatively. The results suggest that previously postulated non-equilibrium effects, namely the prolonged incongruent vaporization originating from high carbon mobility, do not drive erosion over the hours-long timescales of the experiments. For specific in-space propulsion designs, comparisons of carbide performance show TaC and HfC outperform other carbides and meet the criteria needed to close designs.

I found this paper in the archives:
Studies of Hafnium-Carbide Wafers using a Thermogravimetric Analyzer - Captain Domingo G. Castillo and Mr. Paul F. Jones - Phillips Laboratory - Edwards AFB, California

Abstract:
Solar thermal propulsion can improve orbital transfer and maneuvering of space payloads due to double the performance of specific impulse (Isp) over chemical propulsion systems. Solar thermal can accomplish this increased performance by absorbing concentrated solar energy with very high temperature materials which through conduction heat hydrogen (H2). Hafnium carbide (HfC) is an excellent candidate material as a solar absorber and conductor because of its high melting temperature of 3950°C (7142°F)1. Several reticulated vitreous hafnium carbide wafers with varying porosities were made by a commercial vendor. Samples of these wafers were placed in a Thermogravimetric Analyzer (TGA) and heated from room temperature to 1000°C (1832°F). This would determine any weight gains or losses of the wafers during testing. Results of this analysis show that the hafnium carbide increased in weight approximately 2.5 percent.

I never knew this existed before tonight, but I feel like the fact that I have the same ideas that much smarter and more accomplished aerospace engineers have had, apparently since before I was born, means we're on the right track, and we now have high temperature materials tech that simply did not exist in the 1960s to early 1980s.

SOLAR ROCKET SYSTEM CONCEPT ANALYSIS - SATELLITE SYSTEMS DIVISION - SPACE SYSTEMS GROUP - ROCKWELL INTERNATIONAL

SOLAR ROCKET SYSTEM CONCEPT ANALYSIS - Jack A. Boddy - Rockwell International Corporation

Finally... Vindication that this idea for a high-Isp solar thermal rocket is not that far out in left field, it was merely a good idea that never received proper funding and follow-through.

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#26 2025-03-11 17:39:15

Re: Focused Solar Power Propulsion

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#31 2025-03-20 11:37:39

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#33 2025-03-24 13:26:50

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#34 2025-03-24 17:23:41

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#35 2025-03-26 07:23:13

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#36 2025-03-26 18:38:27

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#37 2025-03-27 09:22:25

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#38 2025-03-27 17:05:18

Re: Focused Solar Power Propulsion

#39 2025-03-27 17:17:22

Re: Focused Solar Power Propulsion

#40 2025-03-27 20:58:49

Re: Focused Solar Power Propulsion

Solar Mirror Example and Carnot Clarification

The Gemasolar Example

Clarification of the Carnot Limit

Conclusion

#41 2025-03-27 21:30:21

Re: Focused Solar Power Propulsion

#42 Yesterday 09:26:29

Re: Focused Solar Power Propulsion

#43 Today 01:15:19

Re: Focused Solar Power Propulsion

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