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PhotonBytes is a member of a team working on a design for a space plane (space-plane.org).
A topic is set up to support reporting/discussion of this specific space plane.
Space Plane design by Space-Plane.org
A post containing links and documentation is available:
http://newmars.com/forums/viewtopic.php … 46#p205246
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For PhotonBytes re new proposal for an igloo at a crater on Mars....
I've not had time to read your proposal carefully, but noted a reference to 1 g in the system.
Mars offers a gravity field that is less than 1 G, so I'll be interested in finding out how your design would provide 1 G.
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For PhotonBytes re recent post in Space plane topic...
Thanks for returning to the forum, and for showing your progress with a simulation that appears to show an SSTO concept.
I would be normal and expected for an impressive simulation like this to receive only positive feedback. There is no need to compare the simulation to reality. Reality is painful and disappointing.
However, if you were interested in feedback about how your concept would work in the Real Universe, this forum has plenty of Real Universe data for your team members to study.
It would be astonished if your simulation could hold up to the requirements of the Real Universe.
There is an entire topic dedicated to SSTO, and several members of the forum have taken runs at the challenge.
For all other NewMars members .... please do NOT jump on this initiative by PhotonBytes without careful study of the proposal.
Instead, please let PhotonBytes reveal where he would like feedback. He may not want anything but positive feedback.
A beautifully written simulation that does not match reality has a definite place in the forum, because it is (or can be) a source of inspiration.
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For PhotonBytes re sunken habitat on Mars....
Your initiative in early 2025 seems to have attracted some attention....
This forum has been running for over 20 years. No one joining recently would have time to catch up on decades of discussion.
It seems to me the only practical way to bring new members up to date on settled issues is to create a post (or posts) as needed.
Your work on habitats below ground on Mars seems to retain an unnecessary attachment to Earth standard pressure at sea level.
This forum has adopted a consensus around half a bar of pressure for Mars habitats. Members argue long into the night about decimal places of proportions. For your purposes, a rule-of-thumb of 3-5-8 should help you create a scenario that will be more acceptable to members here.
The 3 is for parts Oxygen.
The 5 is for parts Nitrogen (or Argon)
The 8 is for PSI
The reason for this convention is straight forward. Mars residents must be able to don outside garments without pre-breathing.
When you put on your outside garment you will want to breath 3 PSI of Oxygen.
I am hoping you will revise your concept for a sunken habitat to take this lower pressure into account.
It should be interesting to see how your calculations turn out after you make this revision.
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For PhotonBytes re rapid flight to Mars....
I've asked everyone to hold off on knee-jerk reactions to your new topic.
I'm hoping this interesting initiative on your part will lead to educational opportunities.
Since you are working with an AI assistant (as am I) I know you can ask your assistant to provide more information.
A request I have is for an estimate of the number of refueling flights SpaceX must make to prepare the fleet for this ambitious flight.
I understand that 100 tons of propellant is a reasonable estimate for a tanker, so (presumably) 14 flights would be needed to fill one Starship for the expedition.
If the expedition will use four Starships to facilitate the flight, then 4*14 or 56 flights will be required.
The cost of each fuel mission includes the propellant and rental of the Starship/SuperHeavy service.
It should be just a few nanoseconds work for your assistant to deliver a cost estimate.
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For PhotonBytes re Optical Plane Space Vessel....
Only three folks are working on this project, at the moment...
You have demonstrated skills and interests that might blend into the effort, if you are interested.
The hypothesis in play originated with kbd512. It is that while solar power can be harnessed to create electricity, and thus propulsion based upon electricity, a direct harnessing of thermal energy to heat propellant might be a more efficient process.
No one has actually built a solar thermal rocket, and studies of that option date back to the 1950's, when modern technology was not available.
GW Johnson has offered to provide guidance for aerospace engineering aspects of the design.
I've invited others to assist but so far there are just the three of us working on the project.
The goal set is fairly simple to describe, but success is almost impossible to predict.
We start with:
Power from the Sun of 40 MW (collected by optical devices and fed to a heat engine using optical fiber)
Mass flow rate of 2 kilograms per second (LH2)
Thrust to be achieved: 1/2 force ton or about 5000 Newtons
Temperature of exhaust on the order of 3000 Kelvin
Please note that the combination of specifications given above may NOT be permitted in the Real Universe.
Materials choices and enginering tradeoffs are very much in play.
I have asked ChatGPT4o to ask DALL-E to create artwork for the vessel, and the results are thought provoking.
My hope is that a better image might be possible, but writing prompts for DALL-E is not easy, as you may have found.
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For PhotonBytes re fuel supply during takeoff run...
In a post earlier in July, 2025, my recollection is that you spoke of doing an analysis for someone who was interested in the possibility of providing fuel to an accelerating space plane during the takeoff run.
This concept reminded me of an idea of Calliban's that came back into view recently. This is the idea of giving the space plane a horizontal velocity of just under Mach 1 (eg, 320 m/sec) using a maglev track. A track of 3 kilometers length could accelerate a vehicle to 320 m/sec with a G force of only 2, which would be tolerable for humans.
I'd be interested in knowing how your calculations turn out if you introduce such an initial velocity to the mix.
I understand you only read your own posts so you'll probably miss this, but a small group is undertaking an effort to learn how to do ** real ** flight planning in the SSTO series of topics. You are welcome to join the group if you are at all interested.
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For PhotonBytes re post in Spaceplane topic....
Thanks for including details of opportunities for NewMars readers to contribute to the success of your enterprise.
https://newmars.com/forums/viewtopic.ph … 51#p233051
This is the first time that I can recall that anyone has offered a job opportunity via the forum, and I am **very** interested in encouraging the use of our forum to make such connections. This forum started 20+ years ago at a time when enthusiasm about Mars and space in general was high. Discussions at that time were often about events of the day, with a wide distribution of visions tossed into the mix. In recent times, there seems to be a slight bending of discussion toward practical achievement. The trend is not yet strong, but your post is an example of what I think I'm seeing.
Please edit your post to include direct contact information. I expect the link you provide will be to your web site, and while I intend to bring up this topic in the next Google Meeting, you are welcome to proceed.
Think of this as a supplement to your LinkedIn listings of job opportunities.
I see this as an opportunity to lift the Professional Index for this forum slightly. It is primarily an entertainment site, with a reasonable percentage of activity that might be considered educational.
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For PhotonBytes re Spaceplane topic ...
Thanks for keeping us informed as you proceed.
You used a term that may be new to some of us. In your Spaceplane topic, please explain a bit about the term "air breathing rocket".
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"Air breathing rocket" is a very loose term usually applied to a combined-cycle engine concept combining rocket with turbojet. The other often-proposed combined cycle engine concepts are for hypersonic atmospheric flight, combining turbojet with ramjet or scramjet. Those are different. Both types have been tried many times, and are still being tried. None are fully operational yet, even after half a century of trying. Something flying experimentally is just that: experimental. That would NOT be ready for general application.
Do not confuse "air breathing rocket" the combined cycle rocket-turbojet with either the "ducted rocket" or the air turborocket. Those are different, and the term "ducted rocket" is really vague and misleading. The air turborocket has a fuel-rich gas generator combustor where part of the fuel and some oxidizer are burned to create not-fully-hot gas to drive a turbine, which drives an air compressor that draws air into the engine like a turbojet. The compressed air, the remaining fuel, and the turbine drive gas are then burned together in what amounts to an afterburner duct leading to the propulsion nozzle. Since the afterburner pressure is lower than what is usual in a turbojet combustor can, specific impulse is far lower than turbojet not afterburning, more like a simple ramjet or a turbojet in full afterburn. But it generates static thrust, unlike the ramjet. It is NOT a hypersonic propulsion device: that air compressor is limited to Mach 3 to 3.5 at most, just like turbojets.
The term "ducted rocket" is most often misapplied to either an air augmentation duct about a rocket, or to a fuel-rich solid propellant gas generator-fed ramjet. The air augmentation ring on a rocket acts as an air ejector duct, raising thrust and specific impulse, but only at very low flight speeds. This concept does not work in any practical sense at supersonic flight speeds.
The gas generator in a gas generator-fed ramjet does the same thing that the liquid fuel tank does in a liquid-fueled ramjet: it contains the fuel. With the fuel rich solid propellant, you gain the "wooden round" handling and logistics of a solid rocket, but at the specific impulse of a ramjet. It has high volumetric loading of that energy, but specific impulse is reduced some by the lower heating value of the fuel.
The "solid fueled ramjet" has oxidizerless solid fuel packaged within the combustor. It has inherently low volumetric loading of that energy because the fuel grain must have a large open bore to pass the air, and it needs yet more combustion volume downstream of the fuel charge to enable efficient combustion. But it offers the "wooden round" advantages of the solid plus similarly high heating value and specific impulse as the liquid ramjet. You add oxidizer to the fuel to increase the regression rate, and you negate many of the "wooden round" and heating value advantages.
GW
Last edited by GW Johnson (2025-07-28 09:18:17)
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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For PhotonBytes re questions in SpacePlane topic...
https://newmars.com/forums/viewtopic.ph … 94#p233294
Thank you for your questions about GW Johnson's work.
GW is developing a spread sheet that someone who is designing a non-reusable SSTO could use to try various combinations of features.
The work GW is doing is NOT limited to a specific design, with the caveat that this is for NON-reusable vehicles.
Your question about combinations of fuels is highly pertinent and I will make sure to forward your question to Dr. Johnson.
However, the request for help with specifics of the mass of components remains open for you to help.
If your vehicle has already specified those particular parts, and if your company is willing to share that information, it would be helpful as GW attempts to create a set of interlocking software that can model a wide variety of possible SSTO designs.
In conversation in the Google Meeting last Sunday, I got the impression that GW is attempting to include every significant subsystem in the spreadsheet, in order to arrive at a reliable prediction of performance.
He has specifically asked for details of existing designs for:
1) non-gimbal engine mounts
2) gimbaled engine mounts
3) Plumbing to carry propellant to the engines.
As you would understand, tanks can be estimated based upon volume, thickness and materials properties.
GW's current work is on non-reusable rockets. The idea of trying to design for safe return is for a phase beyond this one. The results of work done to date indicate that if inert mass can be kept in the range of 4%, then LH2 and carbon fuels can reach orbit with a payload that is a modest percentage of the liftoff mass.
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For PhotonBytes as a follow up to #11
The spreadsheet GW Johnson is developing is intended for use by individuals or groups who are designing SSTO as non-reusable systems.
An application I have in mind is delivering ready-to-live-in apartment modules to an orbiting hotel. The engines can be removed and returned to Earth in a large vessel designed for the purpose, and the rest of the spacecraft can be adapted for on-orbit habitation.
Your associates are working on the more ambitious reusable concept. However, it seems to me that the spreadsheet results should be useful for planning the reusable system, if the spreadsheet can accommodate the hybrid fuel situation that is highly likely to be part of the reusable design.
The great advantage of encapsulating the functionality in a spread sheet is it's (nearly) universal accessibility.
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For PhotonBytes as a follow up to #12
GW Johnson is still working on his rocket design family of spreadsheets. I asked him about your space plane idea, and so far I have not been able to persuade him to make a prediction for your scenario.
As a result, I am left with this conclusion:
Based upon GW's results for a rocket to LEO, it appears that such a rocket could reach LEO using either LH2 or carbon fuel, if the inert fraction is no greater than 4%.
From this I deduce that if you fly a space plane with a vertical launch (which the Shuttle did after all) and if the drag coefficient is no greater than that of a cylindrical rocket with a suitable conical nose, and if your inert fraction is 4%,. then the vehicle will reach LEO with a small payload in addition to the vehicle itself.
GW's studies were done for the payload mass of 1 metric ton and 100 metric tons.
My recollection is that the carbon configuration did not succeed at 100 tons, primarily because the rocket engines would not fit under the aft shroud. By increasing the diameter of the vehicle to accommodate the engines, the drag increased to the point that the flight failed.
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For Photonbytes re hydrogen wing tanks ...
https://newmars.com/forums/viewtopic.ph … 71#p233471
While GW Johnson is still refining his rocket design spreadsheets, preliminary results appear to show that a system designed for LH2 and LOX can reach LEO as an SSTO if the inert mass is 4% of the liftoff mass, and the drag coefficient is no greater than that of a cylinder with a conical nose.
The caveats are that flight is vertical to minimize drag, and that every component of the machine must come out of that 4% figure.
If you can do that, then GW's projections would appear to show that your vehicle will succeed.
For completeness, please show details of how your design will allocate mass.
Items that come to mind include:
Structure under skin.
The exterior surface
Motors, pumps, auxiliary power, batteries
Plumbing, including fuel routing
Electronics
You and your associates may be able to pull this off, with modern materials and manufacturing techniques.
In any case, your adventures in pursuing this quest will be of great interest to the audience here, so please bring us along as you document each step along the way.
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For PhotonBytes re Space Plane initiative....
Please keep us informed of the progress your associates are making. You are in competition with teams (as I understand) in the UK and in the US, and there may be other teams at work. GW Johnson has provided a figure you can use with some confidence. If you launch straight up to minimize drag at launch, and if you keep inert components (fuselage, structure, engines, electronics) to 4% of propellant, you should be able to reach LEO. Whether you can return will be interesting to see, but at least you would be the first to reach orbit with a vehicle that uses only one stage to perform the feat. Your chances appear to be better if you can use LH2, but carbon fuel can apparently work as well.
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For PhotonBytes re XLS showing flight plan for space plane ...
Thank you for providing a link to the information you have published.
I'll try to help GW Johnson to look at it. I assume the file we want is 2024.05.01 ?
https://newmars.com/forums/viewtopic.ph … 58#p233558
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For PhotonBytes re discussion with GW Johnson...
At the moment, GW is buried in contracts or bids, in addition to the responsibilities of a working farm and everything else that goes on in Texas (whatever that may be on any given day).
However, I am tossing out another invitation for you and your team to consider Gw's prediction that an SSTO that uses LH2 and LOX can achieve LEO if the inert fraction is 4%. There might be a bit of leeway there, but that is apparently a firm figure you can use with confidence.
I've asked GW to compute the volume of the cylindrical form used for his calculations. I am hoping you can then use that volume to size your lifting body. My hope is that the large volume and low mass of the resulting vehicle will help to address the difficulty of returning from orbit safely.
My hope is that a huge lift surface and low mass will work in your favor, to permit more rapid deceleration and therefore a shorter period of intense heating.
A TSTO space plane is now a well established capability for the US, China and probably other Nations. Your quest to create an SSTO version puts you and your teammates in a very small league indeed. If you are able to implement GW's recommendation, then your vehicle will weigh less that the competition, and it will be significantly simpler. Can you do it? I have no way of knowing, but I sure would be impressed if you can.
Remember! This concept is vertical takeoff only! The landing is dead stick ala Shuttle.
You can save mass by landing on water, so the hull would be shaped for that purpose.
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For PhotonBytes re discussion with GW Johnson...
GW has prepared a set of images that show various aspects of rocket engine design ...
https://newmars.com/forums/viewtopic.ph … 72#p233772
I am unable to upload more images to imgur at present, so have stored the images on Dropbox.
There is text to go with the images, covering design of air breathing engines and how they might apply to your concept for a flying SSTO, but the text is not ready for publication. The drafts are still a bit rough.
That said, I came away from a first reading with the idea that there might be a way to combine multiple engines in a single air frame if you design the air flow correctly. This is my interpretation of GW's text, so it could be incorrect to a greater or lesser degree, or it might even be correct.
It appears that if you design the air frame with the scram jet in the central corridor, and with non-scramjet devices to right and left (or above and below) the main corridor, then those engines can tolerate the bend of air flow. All systems would use the same common intake, but swivel doors would direct the air to the appropriate engine at a given stage of flight.
I am hoping this discussion can continue so that the rest of us (members and readers) can follow along.
***
Update .... PhotonBytes .... if your location ** is ** Australia, then you might be able to attend our weekly Google Meeting. According to Google, it is mid-morning in Sydney when it is 7 PM in Houston. GW has been writing up quite a series of post-sized emails about the space plane, and in the most recent one he described some research done by a US firm to try to combine more than one engine mode in the same air frame. From my perspective, there appear to be good and sufficient reasons why no one has attempted (or admits to having attempted) to build such a vehicle.
I'd like to see you and your associates attempt something where you have no competition... Just use GW's guide for a vertical launch space plane that returns safely from orbit to a deadstick water landing. The entire vehicle needs to comprise only 4% of the propellant mass. If you can design such a vehicle, then GW's figures show it can reach LEO using LH2 and LOX, and if you are able to take advantage of the butterfly effect (low mass vs area) you might be able to decelerate in the atmosphere without massive heat shields. There was some discussion of this idea in the forum recently, but I don't remember who was discussing the idea or where to find it.
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For PhotonBytes re vertical launch space plane ...
In an earlier post I had suggested eliminating mass needed for wheels by landing on water.
GW Johnson reminded me via email that an airframe capable of landing on water must be far stronger (and therefore more massive) than is needed for wheel landing, due to the incompressible nature of water. Water would have to be glassy smooth for a safe landing of an ultra lightweight vehicle.
I looked briefly at glider landing equipment. The minimum wheel count is one under the cabin, with skids at wing tips, nose and tail. The maximum I found is five, with one large wheel under the cabin, and little ones at the wing tips, nose and tail. A space vehicle would have to keep any wheels protected from the atmosphere during re-entry.
Trying to design a space plane with 4% inert fraction will test the skills of even the most talented design team.
GW tells me he might be able to improve that number slightly by fine tuning his vertical launch model. He has a lot of irons in the fire right now, so won't have time to work on this for a while.
It would sure be interesting to forum readership to see what you and your associates can come up with.
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For PhotonBytes re vertical launch two stage space plane to carry passengers ...
Dream Chaser is inching along the pathway to their first flight.
You and your associates are going to have a comparable experience.
I expect that if your venture is in Australia, the authorities there are going to be just as exacting as NASA is right now, after the Boeing fiasco.
GW Johnson wrote that he thinks his existing two stage planning spreadsheets can handle vertical launch of a space plane if you are willing to tolerate inert fraction of about 40% for the space plane. That should be enough to give you heat shields and landing gear.
GW showed me images of side mounted booster/second stage configurations. The ideal would be a fly back first stage. That would be a ** large ** vehicle, but the numbers might add up.
If your associates are willing to adjust your thinking in that direction GW might be able to help with sizing estimates.
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For PhotonBytes re vertical launch two stage space plane to carry passengers and freight...
In email conversation with GW Johnson I created this image to show an idea for a space plane that could be built today with existing technology.
http://40.75.112.55/phpBB3/download/file.php?id=4
Since creating the document for GW, I've had time to revise my thinking.
Those vehicles could be identical. Two would perform the first stage boost and release the middle plane to climb on up to orbit.
All three would fly back to Earth. If you can (somehow) enlist GW to help you with the design, you should be able to find a combination of components that will allow you to built strong, durable vehicles that can stand up to repeated flights with minimal maintenance between flights. You can eliminate the complexity of all the air breathing systems, and you can replace tail dancing with tried and true wing flight.
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