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)
(th)

(th)

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.

(th)

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.

(th)

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.

(th)

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.

(th)

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

(th)

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.

(th)

tahanson43206 · Yesterday 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.

(th)

tahanson43206 · Yesterday 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.

(th)

New Mars Forums

Announcement

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

Re: Focused Solar Power Propulsion

#27 2025-03-11 18:04:46

Re: Focused Solar Power Propulsion

#28 2025-03-12 07:04:40

Re: Focused Solar Power Propulsion

#29 2025-03-20 08:26:24

Re: Focused Solar Power Propulsion

#30 2025-03-20 11:12:04

Re: Focused Solar Power Propulsion

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

Re: Focused Solar Power Propulsion

#32 2025-03-21 11:52:10

Re: Focused Solar Power Propulsion

#33 Yesterday 13:26:50

Re: Focused Solar Power Propulsion

#34 Yesterday 17:23:41

Re: Focused Solar Power Propulsion

Board footer