Risky Speculations, (New Uses of modified existing abilities).

Void · 2024-01-15 13:06:13

I fell that this section of the board is for more professional types, and generally not my speculations, but I do have something that interests me as a potential for SpaceX, that I have not seen any note of so far, so I will put it here, feel free to get rid if this if you want to.

Starship is rightly made with the potential to give access to Mars. But it is a bit of overkill for some other activities that might come to mind. We know that Elon Musk and SpaceX have their hands full with Starship, cannot entertain a mini-starship at this time.

Refilling for the Moon and high orbits requires many tanker flights. I would like to inquire is upper stages for Falcon 9 refilled from Starship and daisy chained together could accomplish any useful tasks in an effective way.

Two options would exist:
1) Go and get 1st stages already in orbit.
2) Bring fresh ones which would not have fairings or payloads into orbit.

So, could you daisy chain these into a booster stick and refill them in orbit to get some task done. This may or may not involve a dragon. So, may or may not be with crew.

In #1 fetching them is trouble, and they may be coked up a bit, but maybe they could burn one more time.
In #2, they would be fresh and not coked up, but you have to lift the mass in a Starship.

I suppose in my wildest dreams I might imagine landing payloads onto the Moon or sending probes out.

Perhaps even landing crew? That is a long shot. Getting them into orbit from the Moon? Very much harder.

I do understand that todays dragon does not have enough life support for a Moon mission.

But just wanted to put this out there and see what might come to it for coments.

Done

Last edited by Void (2024-01-15 14:44:02)

tahanson43206 · 2024-01-15 13:26:18

For Void re new topic ...

Please consider revising the topic header to narrow the scope a bit.

A few months from now, if someone were to come upon the topic, the current title would not contain much information.

On the other hand, leaving the topic title wide open might yield a wide range of contributions.

I'm trying to avoid putting a thumb on the scale, but instead attempting to show alternatives that might exist.

(th)

Void · 2024-01-15 14:45:20

A reasonable request (th). Will this do? "Risky Speculations, (New Uses of modified existing abilities)." (Was "Risky Speculations").

I can get more specific if you need it, such as SpaceX, or Falcon 9. Let me know.

The Falcon 9 family has several components. I think they are all designed to be of light materials but cannot bring a 2nd stage down to Earth. However, Dragon Capsule can return to Earh.

The Falcon 9 family can get 2nd stages and the Dragon with Trunk into orbit.

Starship would also be able to bring those to orbit if that was desired.

Starship is designed to get to Mars by the ends of its fingernails. It is a worthy goal.

I appreciate the value of Lunar Starship, it will be good for an initial temporary base and to land large cargo to set up a more permanent Moon base. But it needs so much filling, I would not want to consider it to be a proper taxi, after insitu is set up on the Moon with tight recycling.

OK, I am not the only one to think about this: https://arstechnica.com/science/2020/08 … mplicated/ Quote:

GRAY DRAGON —
Could a Dragon spacecraft fly humans to the Moon? It’s complicated
"Do you really want to get to the Moon by 2024 or not?"
ERIC BERGER - 8/16/2020, 10:00 AM

Now my point is that SpaceX is going to have its hands full. After they get Lunar Starship to fulfill NASA's order, then they have to bring forward all the other potentials of the new family.

Some talk has it that it makes more sense to simply manufacture one use 2nd stages and then discard them. Of course this then does not allow very well for low-cost refilling in LEO.

But if modifications of some parts of the Falcon 9 family were introduced than SpaceX could do both, and perhaps even more. A hardened Humanoid Robot might fit into this as well, Optimally

I realize that Falcon 9/Dragon, are not quite ready for the Moon. The fuel will gel at cold temperatures and the LOX will boil off. But modified 2nd Stages and Dragons if supported might be able to do something, at least with a Humanoid Robot.

I think the point is some visits to the Moon do not need the overkill that Lunar Starship would provide.

It might be possible to send probes to the Moon using Starship supported Falcon 9 Hardware, maybe even get some sample rocks back for locations that you would not send humans to.

It might even make sense to find a way to change out crew, but I am less sure of that.

Done

Last edited by Void (2024-01-15 15:05:04)

SpaceNut · 2024-01-15 15:07:51

Falcon 9 heavy can loft 63mT to orbit and would require much in a new upper stage alterations to change that to a payload tank for fueling for sure of course there is no need for the capsule or for the abort functions that the capsule has.

Void · 2024-01-15 15:23:26

That circles back to the known.

What I am after is to make a stick of Falcon 9 upper stages and to refill that with Starship. Then put what payload item you want onto that stick.

For instance maybe somehow one segment of that stick would be a lander that would land an Optimus specially hardened to tolerate a Moon environment.

If you go back to post #1, you will see that I allow for both the possibility that a Falcon 9 would launch the 2nd stages to orbit, or that a Starship would carry them to LEO.

The objective would be to be able to put a payload to parts of the Moon where it is desired to do some research.

For instance not knowing how many segments are needed for such a mission. lets say 3 booster stages to get to the Moon, 1 to land. Maybe one left in orbit to receive sample sent up somehow. A capsule to land the rock samples into a Utah desert, something like for Bennu. Some of the stages would be discarded to deep space. That would not so much be considered dangerous space junk.

Done

Last edited by Void (2024-01-15 15:26:56)

RobertDyck · 2024-01-15 21:41:28

My proposal from 2016: Moon mission today - Dragon & Mars hab
This would use 2 launches of Falcon Heavy. One to launch a reusable Lunar Module unmanned, leaving it parked in lunar orbit. The second would launch a new upper stage in addition to the existing upper stage, and a Dragon capsule with crew. The new upper stage would enter lunar orbit, refuel the LM, and deorbit the LM. Dragon trunk would depart lunar orbit, Trans-Earth Injection. No use of Starship at all. No lunar space station. Second and subsequent missions would only require a single Falcon Heavy because the reusable LM would be left in lunar orbit.

SpaceNut · 2024-01-16 19:11:25

Zubin had a page for MOON DIRECT: HOW TO BUILD A MOONBASE IN FOUR YEARS that did plan to make use of the Falcon 9 heavy.

Here is the discussion that followed Dr. Robert Zubrin Moon Direct: How to build a moonbase in four years

Void · 2024-01-16 20:09:51

Those are all worthy conversations, and I will be happy to continue with them and do appreciate your participation, but I had something weird in mind, (Of course)

Dry Mass and Wet Mass of Falcon 9 2nd Stage: https://www.quora.com/What-is-the-WET-m … g-dry-mass Quote:

we have :
First stage Mass (‘dry’ without propellant) 22,200 kg (48,900 lb)
Second stage Mass (without propellant) 4,000 kg (8,800 lb)
First stage Mass (‘wet’ with propellant) 433,100 kg (954,800 lb)
Second stage Mass (with propellant) 111,500 kg (245,800 lb)

I think Quote:

Second stage Mass (with propellant) 111,500 kg (245,800 lb)

, could be carried to orbit with a Starship. Possibly even two of them if Starship goes to the more fanciful estimates.

And I think if you got rid of the Fairings it would be lighter still.

So, then the question is could you do anything useful with one or two of them, perhaps modified in some way?

Comparing Starship and Falcon 9 2nd Stage is like comparing a horse and a mule, perhaps in this situation.

2nd Stage Falcon 9 is light weight, but the propulsion system is not as good as raptors. But still, as you do not intend to use the Falcon 9 2nd stage and then return it to Earth, then you may max out its propellants for some mission.

Can anything be done with it?

Also, might it be modified to do something with the Moon?

Can you daisy chain them as 1st, and 2nd stages?

Less likely would be to retrieve a Falcon 9 2nd stage already in orbit, and refill it. The Merlin Engines coke up, but maybe you would get one or two more burns out of the engine. Could you retrieve one with a Starship? Could you use an electric rocket to fetch it?

Well for the moment that is the hardware item I am interested in Falcon 9 2nd stage.

It would be wonderful if SpaceX could make a Mini Starship that would run on Hydrogen and Oxygen, but I think their plate if full at this time.

But Falcon 9 2nd stage is still being manufactured and might fit into a single Starship lift.

Done

OK, I should recant, 100 to 150 tons is the stated reusable Starship payload, so at best you might lift 1 Falcon 9 2nd stage, and it might need to be a little short of propellants unless you filled it at a propellant depot.

But still a fun question, I feel.

Done

Last edited by Void (2024-01-16 20:36:06)

Void · 2024-01-17 20:42:27

Here is an interesting product, (Stoke Space): https://www.msn.com/en-us/news/technolo … 0d94&ei=17

Now if that were sized up, and refueled in orbit (Hydro Lox), and on the Moon, you would have something like what Dr. Zubrin suggested.

But I don't know if the heat shield method could hack a reentry at such a high speed from the Moon.

Terran-R 2nd stage will not have a heat shield at all but could be refueled with (Metha Lox).

Done

GW Johnson · 2024-01-18 11:00:34

Void:

An actively liquid cooled metal heat shield is one concept that would have been tested on the X-20 Dyna-Soar back in the mid-1960's. Unfortunately, the X-20 was cancelled in 1963 just as the first 3 prototype vehicles were nearing the end of the assembly line at Boeing. No one has done active cooling on heat shields since. Until now, apparently.

Crudely speaking, stagnation zone convective heat rate per unit area is proportional to velocity cubed, proportional to the square root of ambient atmospheric density, and inversely proportional to the square root of "nose" radius, which factor can be quite large for a blunt heat shield, but quite small for a blunted-cone warhead. That's why pointy things burn up faster.

Convective heating is all there is to deal with, up to crudely about 10 km/s at entry interface, beyond which plasma sheath radiation heating massively dominates over convection. It is crudely proportional to velocity raised to the 6th power. When that occurs, you also lose the ability to shed entry heat by re-radiating to space, which is how shuttle tile and X-37B tiles work. The glowing plasma sheath becomes opaque to infrared. It has been opaque to radio from about 5 km/s on up.

At which point, the only known and proven solution is ablatives. Conceptually, there is also active cooling, but the heat rate quantities to be dealt with are astronomical, if you will forgive my choice of words.

Entry from LEO takes place at about 7.8-8.0 km/s. Some slightly higher orbits lead to entry speeds in the 8-10 km/s range, but you very quickly start talking about ellipses with entry speeds in the 10-11 km/s range. Escape is 11 km/s.

Looks to me like the non-ablative solutions are restricted pretty much to LEO. Coming back from the moon is about 10.9 km/s at entry interface. Coming back from geosynch would be pretty close to 10 km/s. Radiation heating from the plasma dominates, and by far. There is no re-radiation cooling at those conditions, because the brightly-glowing plasma is opaque to infrared, as well as radio.

The "ring of fire" thing is a clever way to put propulsion and a heat shield on the same end of the vehicle. I will have to think further about that one.

GW

Void · 2024-01-18 12:28:17

Thanks for the advice, Dr. Johnson, I am honored by your presence.

Done

This leads me to wonder if an ablative heat shield for a capsule type of ship on the Moon, to support a path from the Moon to atmospheric entry to Earth.

I believe members here have done some speculations on similar thoughts.

Such a heat shield would have to be ejected after the heat pulse is over, I suppose and then you would be using the ships engine.

Maybe it could be a flexible mineral cloth to give heat protection assistance?

Just a try.

Done

I found this: https://ntrs.nasa.gov/api/citations/201 … %20reentry.
Quote:

An ablative heat shield is required to endure the heat produced from lunar orbit reentry and provide the protection needed. An ablator dissipates heat by means of a melting heat shield, resulting in a single use TPS system. The crew module (CM) needed to have limit temperature at the ablator-steel interface of 600°F during reentry.
Thermal Protection and Control - NASA Technical Reports Server (…
ntrs.nasa.gov/api/citations/20140002341/downloads/20140002341.pdf
ntrs.nasa.gov/api/citations/20140002341/downloads/20140002341.pdf

https://worldbuilding.stackexchange.com … -get-cargo Quote:

Within the scope of the testing to date, the feasibility of using extraterrestrial regoliths as the construction material for atmospheric entry heat shields has been confirmed from the results of the acetylene flame and arc jet testing. While some of the arc jet-tested samples were heavily ablated, they provided adequate low temperatures on their rear surfaces. These rear surface peak temperatures were recorded several minutes after arc jet test termination.

So, I think maybe it could be that a combination of a one time ablative heat shield and also perhaps active cooling might do the trick for high speed returns from the Moon.

Maybe.

Done

Last edited by Void (2024-01-18 13:17:16)

tahanson43206 · 2024-01-18 13:14:06

For Void.... re #11 but entire topic so far ....

Your creative imagination occasionally comes up with an idea that has a chance of general acceptance.

The primary example is your suggestion that some freight might be delivered to Mars without a parachute, and you've inspired some NewMars members to examine your idea in sufficient detail so that a viable business opportunity exists.

I see your latest venture here as having similar potential.

The ablative heat shield that a space craft requires for entry to Earth's atmosphere after a journey to the Moon or Mars (or practically anywhere else in the Solar System) does NOT have to be made on Earth. In fact, if the ablative heat shield is NOT made on Earth, then all that dead weight does NOT have to be carried up from the surface, and all the way to the Moon or Mars.

The idea that I am seeing (or think I am seeing) in your post, is of making ablative material for Earth deceleration from the Moon, or perhaps from other Solar System resources.

What caught my eye was your hint that the ablative material could be discarded after it has done it's job. Hopefully the ablative material would be discarded over the ocean, and no ships or small boats are in the descent path, but dropping the mass of the shield would reduce the mass to be further decelerated for a soft landing on the Earth's surface.

(th)

GW Johnson · 2024-01-18 14:43:22

The idea of a 1-use heat shield made of lunar regolith is intriguing. You are working with minerals of igneous-type rocks, somewhat similar to granite.

Whatever/however you do this, the heat shield must have a significant void fraction, it cannot be a solid mineral. That is the only way to achieve a low effective thermal conductivity, in order to limit the heat conduction through the heat shield into the interior. The same thing would be true of the metal heatshield in the link above: you have to have a low conductivity insulation layer between it and the craft interior.

The exterior surface temperature of a mineral heat shield is very likely going to be the meltpoint of the mineral (same might be true of the metal). The "ablation" rate will be fairly high, controlled by the latent heat of fusion of the mineral, relative to the net applied heating.

GW

Void · 2024-01-18 19:35:04

Thanks for that teaching Dr. Johnson.

I will not chase the notion further because I think it needs expert work to be safely done, and I have seen evidence that some entities have already worked on it a bit. I have seen mention of NIAC and NASA in some of those articles.

General Example:
https://www.bing.com/search?q=making+he … FC&pc=U531

Single Example: https://phys.org/news/2012-09-alien-soi … s%20needed.

Quote:

Researchers to test alien soils for use in heat shield
by Steven Siceloff, NASA
Making the heat shield in space would likely be the work of a robotic device, or at least a heavily automated system to either mix the regolith with a rubbery substance in a mold or heat a large disc of regolith until the soil elements fuse together. The heat shield could then be cut and shaped as needed.

It seems to have been a topic around 2012, 2013, 2014, and then some mentions more recently:
https://www.nasa.gov/wp-content/uploads … tagged.pdf
https://www.nasa.gov/general/regolith-d … brication/
https://worldbuilding.stackexchange.com … -get-cargo

So, it appears that some people think it can be done.

Done

Last edited by Void (2024-01-18 19:45:24)

Void · 2024-01-19 13:38:27

I think this is worth thinking about:

Pretty much intends that large scale manufacturing can make Moon Shells which could be used one time, but would in large part be a resource delivery.

It may make it possible for Stokes, or SpaceX or others to return a 2nd stage without a standard heat shield method to the surface of the Earth or to Earth orbit, I hope. At the same time perhaps delivering mass of value to the delivery point. Such as Liquid Oxygen.

I am presuming ablation of materials from the Moon as the heat shield method. Hopefully it could be done.

A lump of Oxygen ice might help in cooling the device. Possibly Aluminum in a container also could transition from solid to liquid. However ablation if it could be done might be the quick and dirty way to do it.

This then could give Lunar Starship a method to use aerobraking to return to Earth. And then your Starships don't have the expense of installing a heat shield and lifting it to orbit.

Good chances you would want Starship to bring up propellants for this process, but of course I have suggested propellants delivered from the Moon as well, as an option.

Done

A few more notes. A Moon Shell could have a better mass to air footprint ratio than a 2nd stage. If it has more surface area to mass than a 2nd stage, then the heating may be less per area unit. (I think. I think there may be concerns about the center of the shield).

It also will be possible that with the engine bay at the back of the ship, you might be able to force the ship to stay in the atmosphere and slow down more, when it wants to skip off the atmosphere. This presumes a refill of the ship at the Moon, at least of Oxygen maybe a fuel as well.

That would be for aerocapture, and you would come in shallow so as to glance off the atmosphere but push the device deeper into the atmosphere with the engines, to force the assembly to encounter more molecules of atmosphere before the skipping even occurs.

You might roll the ship after you skip to modify the orbit with the engines to arrange for another skipping event.

I am sure Dr. Johnson could add corrections to these notions.

Done

Here is a different version:

I would hope that the interior surface might be a honeycomb texture to make more surface area for heat to radiate from. And I don't know it this would be helpful at higher speeds such as coming from the Moon.

Two Moon Shells perhaps delivered to Earth orbit might be welded together at the bases to create a prescribable space. Or the materials may be scrapped to make things out of.

Just trying.

Done

One notion on how to deposit ablative materials on the outside of a Moon Shell might be vacuum deposition.

https://en.wikipedia.org/wiki/Vacuum_deposition
Quote:

Vacuum deposition is a group of processes used to deposit layers of material atom-by-atom or molecule-by-molecule on a solid surface. These processes operate at pressures well below atmospheric pressure (i.e., vacuum). The deposited layers can range from a thickness of one atom up to millimeters, forming freestanding structures. Multiple layers of different materials can be used, for example to form optical coatings. The process can be qualified based on the vapor source; physical vapor deposition uses a liquid or solid source and chemical vapor deposition uses a chemical vapor.[2]

Perhaps a modified Neumann thruster might work to send the materials to a Moon Shell as a target. Various materials can work in a Neumann Thruster. https://neumannspace.com/

Here are the materials that the Neumann drive can eject: https://neumannspace.com/metal-propellants/
Quote:

WHY ARE WE USING METALS?
Our system can use any solid, conductive material as a propellant since the arc cathode is the propellant. This differentiates it from pulsed plasma thrusters which strike an arc across the surface of a polymer propellant rod, rather than striking the arc from the surface of a conductive cathode.
The physical properties of metals lend themselves well to spacecraft propellant storage, as most metals are inherently safe in the vacuum and radiation environment of space. This removes the need for propellant stowage systems such as tanks, the mass of which can be devoted to more payload. Similarly, the greater density of other propellant metals reduces volume, freeing up space for other systems.
WHICH METALS?
Our system is not limited to pure metals; alloys and electrically conductive forms of carbon, silicon and similar elements can also be used. We have found that refractory metals such as molybdenum make excellent propellants, and recycled aluminium alloys can also be used. Exceptions include mercury and gallium, tin, bismuth and lithium (due to their low melting points), cadmium and technetium.

Of course, we want the texture that Dr. Johnson has specified. Quote:

Whatever/however you do this, the heat shield must have a significant void fraction, it cannot be a solid mineral.

The shell itself would probably be of some metal(s), perhaps 3D printed by a device similar to what Relativity Space uses. https://3dprintingindustry.com/news/rel … ng-216149/ Quote:

RELATIVITY SPACE UNVEILS NEW FOURTH-GEN STARGATE 3D PRINTER: TECHNICAL SPECIFICATIONS AND PRICING
PAUL HANAPHY OCTOBER 24TH 2022 - 9:51PM 0 0

Materials to make the shells out of might be those not valued for other uses on the Moon such as Solar Panels.

Blue Origin has Blue Alchemist to make Solar Panels on the Moon: https://www.blueorigin.com/news/blue-al … nar-future

Done

Last edited by Void (2024-01-19 16:22:18)

SpaceNut · 2024-01-20 08:35:56

here is the heatshield from Extraterrestrial Regolith https://ntrs.nasa.gov/api/citations/201 … 023114.pdf

https://www.nasa.gov/wp-content/uploads … tagged.pdf

The heatshield saves on fuel needed for the entering craft to do final braking in landing with no parachutes.

Overview of Heatshield for Extreme Entry Environment Technology (HEEET) Project

https://ntrs.nasa.gov/api/citations/201 … 000343.pdf

The cloth heatshield is under teh ADAPT project with a woven material
NASA's "game changing" foldable heat shield makes first flight

?url=http%3A%2F%2Fnewatlas-brightspot.s3.amazonaws.com%2Farchive%2Ffoldable-flight-3.jpg

trade off is equipment and energy deliverd to mar to make it possible.

Void · 2024-01-20 17:27:52

Thank You Spacenut.

Done

So, then with my child's color crayons I will try to go further with the picture.

A Moon Shell, could perhaps also include rockets from Lunar Materials:

Query: "Rockets made from lunar regolith"

General Response: https://www.bing.com/search?q=Rockets+m … cc=0&ghpl=

https://www.sciencedirect.com/science/a … 6520306962
Quote:

Research paper
The regolith rocket—A hybrid rocket using lunar resources
Author links open overlay panelEnrico Stoll a, Philip Härke a, Stefan Linke a, Francesca Heeg a, Stefan May b

This suggests the Oxygen anyway: https://aerospaceamerica.aiaa.org/depar … ropellant/

This one suggests a hybrid again, Oxygen and Aluminum: https://www.researchgate.net/publicatio … _resources

So, the idea is not totally out of the question, to make a "Moon Shell" and get it to Lunar orbit using hybrid rockets.

Gotta Go.

Done

Last edited by Void (2024-01-20 17:48:03)

tahanson43206 · 2024-01-20 19:25:16

For Void re a quote from #15

I've been pondering your ideas in this quote:

Of course, we want the texture that Dr. Johnson has specified. Quote:
Whatever/however you do this, the heat shield must have a significant void fraction, it cannot be a solid mineral.
The shell itself would probably be of some metal(s), perhaps 3D printed by a device similar to what Relativity Space uses. https://3dprintingindustry.com/news/rel … ng-216149/ Quote:
RELATIVITY SPACE UNVEILS NEW FOURTH-GEN STARGATE 3D PRINTER: TECHNICAL SPECIFICATIONS AND PRICING
PAUL HANAPHY OCTOBER 24TH 2022 - 9:51PM 0 0
Materials to make the shells out of might be those not valued for other uses on the Moon such as Solar Panels.

I'm making an assumption here ... please correct me if I'm wrong ... It seems to me possible you have 3D Printing on your to-learn agenda, but may not have gotten around to it, because you've been learning so many other topics. Thus, it is possible you may not be aware of a common practice in 3D Printing. I bring this up in the context of the need to create foamy basalt for Lunar heat shields. In printing with a 3D Printer, you will discover, when you find time to dive in, that there is a common practice in 3D printing of designating a "fill factor" for your creations. A "fill factor" can be 100% (solid) or a lower figure such as 50%. If your model does not require the strength of a solid, and you want to save money, you can set the "fill factor" to some value that is sufficient to enable the model to hold up under handling, but does not consume expensive build material when it is not needed.

In thinking about GW Johnson's request/advice to provide air space, it occurred to me that a 3D Printer able to print regolith (not something available today) would be able to print an entire heat shield with varying fill factor throughout the form. There may be a way for an engineer to determine what fill factor is most useful at various places in the shield.

A related question is whether it is possible to make a useful heat shield with vacuum in the enclosed cells, instead of a gas. On the Moon, vacuum is readily available, while gas of any kind would require energy to produce.

It seems to me that software that models flows of gas or liquid with respect to solids would be helpful in analyzing potential performance of various basalt heat sheild designs. There are commercially available packages able to perform these computations. There are Open Sources versions that I understand are well supported by the college community, and I'm confident NASA has it's own versions for it's own operations.

(th)

SpaceNut · 2024-01-20 20:21:10

Here is some more research on making use of the regolith for a heatshield.
In-situ Lunar Launch and Landing Pad Construction with Regolith-Thermoset Polymer Composite Materials

Mix the regolith with the RTV and 3 D print to shape allow to harden and use with a bit more hardware retrofitting.

Other option is to fuse it with heat in the system with a laser quite possibly.

NASA’s Lunar Surface Innovation Initiative – Regolith Processing for a Sustainable Presence on the Moon

tahanson43206 · 2024-01-20 21:45:14

For SpaceNut re #19

Thank you for the links with text in #15

I called up the landing pad pdf and found that at least one configuration tested consisted of pavers held in place with glue.

This leads me to ask if pavers might work for the heat shield application.

I wonder if the pavers might erode gracefully in front of a decelerating space vehicle.

GW Johnson recommends a foam like structure for the basalt heat shield, and that appears to be possible.

However, I'm wondering if simple plain basalt pavers attached to the front of the vessel to be slowed might survive long enough so that they could be ejected (over the ocean) and the space craft would have slowed enough to handle the rest of the flight on it's own?

Meteors seem to show that the right kind of material can survive an encounter with the atmosphere of Earth.

(th)

Void · 2024-01-21 08:48:45

(th) and others, please continue which your heat shield questioning.

But I have been working on a propulsion scheme, and last night decided to keep quiet about it as I felt and still to some extent feel, that I might humiliate myself. But this morning I think I should go ahead and say what I think I have, as it is possible that someone else may be able to make something useful from it.

Pause........

I will describe the level of development I gave up on last night and then what I can up with this morning because they add together.

This is a setup where a rocket system could lift a shell from the Moon, provided it had the propellants and the power levels needed.

But what if you tried to turn the red shell into the shape of a rocket engine bell. The payload then would be your propellants, which I think would include Oxygen, and then fuels as well. I am going to get weird about the fuels.

The fuel of last night would be a preheated sponge cone of Metals. I think others have considered liquid Aluminum.
This would instead be heated to incandescence prior to launch, up to the point of destruction but not quit that hot.
The sponge would insulate itself, and be porous, probably 3D printed. It may contain more than one substance, not just Aluminum.

Last night I was thinking about the German Coal powered jet: https://en.wikipedia.org/wiki/Lippisch_P.13a
The plan would be to shoot streams of Oxygen at the outside of it to produce combustion. I also felt that as there could be more than one such injector inside of the engine bell, shooting at the sponge metal cone, you might be able to throttle these and so steer the bell as it launched upwards to a suborbital path. Then I was hoping that the metal sponge would insulate itself well enough that you could do a second burn, as you got to the other side of the Moon.

But then last night I realized that you then needed a heating and pumping process for the Oxygen to do this. So, I felt stupid, and decided to stop. But this morning, I think I may have something more for that.

An Alice Rocket might suggest something: https://en.wikipedia.org/wiki/ALICE_%28propellant%29
However Alice has a frozen matrix of water and metal fuel, Aluminum powder.

I want a metal sponge that is preheated, the preheating also adding to the propulsion of the device.

And so now, I realize that I want something like a cutting torch. Alice benefits from Metal Oxide particles steam and also some Hydrogen liberated from the interaction of steam and Aluminum.

So, now I want Cutting Torches to be the nozzles that inject Oxygen rich hot gasses onto the metal sponge.

Pause.............

https://www.bing.com/videos/riverview/r … &FORM=VIRE

A fluid fuel will be needed, Hydrogen could maybe come from the Moon, but a fuel might also be delivered from elsewhere, perhaps the Earth. The video has Acetylene, I won't rule that out, Methane imported might work, but I think RP-1 would be nice to try, as storing it is not so much trouble.

That fuel might need to be preheated a little to keep it from gelling. https://en.wikipedia.org/wiki/RP-1
https://www.wikihow.com/Use-a-Cutting-Torch

I am hoping that the Oxygen and fuel tanks could be pressurized with some Argon Gas, to make the propellants travel into the torch nozzles. Argon may come from the Moon, I hope. Otherwise, it needs to be imported.

The energy of propulsion would be from the heated sponge, and also from the Oxygen rich exhaust from the nozzles, and then finally the combustion of the metal sponge in the streams of Oxygen rich hot gas from the nozzles.

So, if this could be made to work, then the Moon Shell would be an uncrewed launch, and then once in orbit a ship would go and dock into it's interior, and then propel it to an Earth encounter, possibly including an Aerocapture. I suppose you might want to try to get into the atmosphere and drop the Moon Shell into the ocean, and then land your ship which would hot have a heat shield, but the value of the Moon Shell in orbit may be quite high.

This method then would help to introduce Hydrogen into the exhaust stream, but the bulk of the fuel would be the metal sponge.

Well, I gave it a good try. Maybe someone can make it practical.

Done

I need a pause. Perhaps I will make a block diagram later.

Done

Last edited by Void (2024-01-21 09:42:10)

Void · 2024-01-21 10:06:51

OK here is my try:

While the cone can be the bulk of Metal Sponge fuel, the inside of the bell could also be a fuel metal. To burn away as you go, the outer shell might perhaps be of some kind of Iron based alloy, perhaps.

I have not shown the aerobraking function, just the launch function. In reality the Oxygen and Fluid Fuel tanks would need to be integrated into the profile of the Moon Shell.

Then we might hope to use ablatives for the aerobrake function.

Some possible way to absorb heat on some surfaces, might be that if some aluminum still is on the interior of the shell, it may melt, but still stick to the non melted, Iron based outer shell. So, for some part of it solid to liquid phase change may help.

If we are carrying Oxygen as a payload, then if it is ice prior to aerobraking, you might sink some heat by melting the Oxygen to a liquid.

Just trying to include as many possibilities as may be available.

It is possible that this may actually not combust all the Oxygen boiled, so it would be an Oxygen Steam rocket to some extent. I am not saying that would be efficient, but for traveling once you are in an orbit, it might be OK, as Oxygen is something we might get in bulk from the Moon.

The interior of the Moon Shell is designed to burn off as well, and may be combustible metals.

Combustible Metals: https://umdearborn.edu/environmental-he … re%20items

Some of these may come from the Lunar Regolith: Quote:

cerium
cesium
lithium
lutetium
magnesium and magnesium alloys
neodymium
phosphorus
potassium
potassium-sodium alloys
rubidium
sodium
strontium
aluminum (powder)
beryllium (powder)
nickel catalyst (Raney)
titanium (powder)
zinc (powder)
zirconium (powder)
aluminum phosphide
calcium carbide
gallium arsenide
gallium phosphide
lithium aluminum deuteride
lithium aluminum hydride
lithium aluminum hydride bis(tetrahydrofuran)
lithium amide
lithium borohydride
lithium-6 deuteride
lithium hydride
lithium tetraphenylborate tris(1,2-dimethoxyethane)
lithium tri-tert-butoxyaluminohydride
magnesium hydride
phosphorus pentasulfide
potassium hydride
Red-Al
sodium aluminum hydride
sodium bis(2-methoxyethoxy)aluminum hydride in toluene
sodium borohydride
sodium borohydride cobalt-doped
sodium borohydride on alumina
sodium hydride
zinc phosphide

On the Moon metal fuels such as Aluminum could be devoid of a protective Oxidized layer. So, more combustible.

https://www.explainingspace.com/what-is … re%20items Quote:

Component Presence in Lunar Regolith
Major Elements Silicon (Si), Iron (Fe), Calcium (Ca), Aluminum (Al)
Minor Elements Titanium (Ti), Magnesium (Mg), Manganese (Mn)
Minerals Ilmenite, Pyroxene, Olivine, Plagioclase Feldspar
Physical Properties Fine texture, Abrasive, Adhesive, Varying density

At least Aluminum and Magnesium will combust. Other materials may be included as propulsion mass ejected with the burn plume.

Done

One way to preheat the metal sponge and the bell itself would be inductive heating.

The bell structures delivered to Earth orbit may be joined perhaps into prescribable containments. Otherwise it is a way to deliver Moon materials to become resources in Earth Orbit.

I am hoping that this is a better scheme than Mass Drivers.

The Moon Shells might also protect orbital assets that might be stored inside of them from impactors.

Done

Last edited by Void (2024-01-21 10:27:23)

Void · 2024-01-21 11:35:15

In an aerocapture use, if you have a Iron Based Metal outer layer, perhaps protected in part by ablative materials, and you have an Aluminum inner layer that may melt, adhesion may keep the Aluminum inside of the bell. But it could be possible to induce a spin on the bell, to create a synthetic gravity to help keep the Aluminum inside of the bell.

The Aluminum would be radiating heat off of it at a very high rate and should solidify relatively quickly I think.

Done

Void · 2024-01-22 07:09:42

OK, I guess you would want an Oxidizer side turbopump process.

This thing would more or less be a flying engine. I think the engine pressure does not have to be super high, but you might want some special tensile materials on the outside of the bell to allow some significant pressure.

Done

tahanson43206 · 2024-01-22 07:47:45

For Void re made-on-Moon regolith heat shield ...

Honeycomb ....

The 3D Printer fill factor I tried to explain to you earlier creates a honeycomb structure as it builds the interior of a model.

This is a detail that might be important, if you decide to investigate the practicality of implementing the method.

I had originally imagined the 3D Printer would make little cells of regolith material, but upon reflection, I realized that is not necessarily the case.

The programmers who create the software that is used at the extruder are NOT the ones who create the model. The model is created using a high level language such as Blender or Fusion 360 (there are many such). The output of the model is an intermediate language that contains the specifications for points where material is needed. The extruder programmers then take in the intermediate language and translate ** that ** into instructions for the extruder manipulators.

I bring this up because a heat shield made of a honeycomb of regolith would have some interesting properties at the time of use as a heat shield. Assuming the honeycomb is made on the Moon, the cylinders of the comb would be empty of molecules due to the vacuum on the surface of the Moon. As the heat shield encounters the atmosphere of Earth (or Mars) the cylinders would fill up with molecules. These molecules would be bouncing around vigorously inside the honeycomb cylinders, which would yield a photon of thermal energy with each bounce. Thus, the heat shield would experience heating throughout the length of the honeycomb. This might become significant. An ordinary heat shield would (I am guessing here) experience heating only at the surface, as material is worn away.

It is possible your topic here may inspire a (probably much younger) person to use software tools to investigate the situation, to see if such a heat shield design would have any advantages over traditional "surface only" designs.

SearchTerm:Honeycomb heat shield

Even as I post this, I recall that honeycomb structure has been used in heat shields for some time, but those honeycomb columns are filled with material that is allowed to dissolve as atmosphere molecules encounter the heat shield. However, ** this ** design would have empty space inside the honeycombs.

(th)

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