Alternate BFR (Big Falcon Rocket)

Void · 2020-05-29 10:23:12

This article indicates that SpaceX will use propellant depots in Earth orbit.
https://www.ibtimes.com/spacex-reveals- … ok-2983128

This leads me to a lot of speculation on how things might evolve.

For one thing, I wonder it instead of the bottom to bottom transfer of Starship and Starship propellant will be used at all.

I am thinking that a propellant depot could spin just a bit, and have pumps to fuel a Mars, or Moon bound ship.

I do think that a propellant depot, could have large separation between the Oxygen and Methane, so as to reduce the possibilities of a large scale explosion. A large explosion could be bad for the creation of space junk. Another safety feature could be that the Propellant Starships, could be specialized to either carry Oxygen or Methane. That would also reduce explosion dangers, both on launch, and in orbit situations.

If it were mildly spinning, then perhaps the starships could dock at the hub and be filled in a manner more similar to when on a planet.

To get the propellants out of the Propellant ship offloaded into the depot, perhaps even at the hub with very low spin gravity around the starships main axis, even then it might be possible to draw the propellants off with a pump.

Eventually perhaps Oxygen from the Moon to the propellant-orbital stations-depots.

Just speculation.

Last edited by Void (2020-05-29 10:33:36)

Void · 2020-05-29 20:57:37

When the cargo is the spaceship itself.

This is similar to where I wanted to consider dropping airbags on to the surface of Mars, where the airbags are their own airbags.

It is also similar to a SSTO Starship stripped down (No heat shield, no landing legs), where the cargo is the ship itself.

And so, I stray next into electric propulsion ships that are consumed from Martian orbit to the Martian surface.
This is a possible propulsion system, but really I would be interested in looking at any electric propulsion system for orbital space.
https://www.dailymail.co.uk/sciencetech … -HALF.html
Quote:

Prototype rocket engine developed by Made in Chelsea star could HALVE the journey time to Mars and pave the way for nuclear-powered interstellar spacecraft travelling at 500,000mph
Argon ion-powered thruster test by Pulsar Fusion reached around 56,000mph
If scaled up to industrial scale it could reach a maximum speed of 100,000mph
But at greater temperatures a similar engine could allow for nuclear fusion
This would be able to reach a top speed of around 500,000mph in space
Conventional propulsion would be required to reach orbit before the fusion reactor takes over in long-duration space travel

I have no idea, if they may eventually incorporate fusion into the system, and I don't that much care. I just, at this time am interested in Argon propellant electric energy thrust.

In the previous post I have suggested that consideration might be made of how to reduce explosion dangers having to do with Oxygen/Methane propellants. It will not be possible to entirely eliminate all such risk. I actually spooks me that I posted that before sn4 disassembled. Oh well.....

Here I am interested in Argon as a propellant, and solar panels as a propulsion energy source.
They may very well have to be delivered to LEO with a Starship, after that these parts have a very reduced mechanical failure risk of sudden disassembly.

Obviously I am intending that electric spacecraft will be assembled in LEO, from parts delivered by something like Starship. My intention is that all components will be "Bite Sized" per the cargo holds of such Starship(s).

What can be assembled in LEO, could then be dis-assembled in Low Martian Orbit. A Starship there then bringing the parts to the surface of Mars.

This then will not be a case of hardware reuse in a repetitive pattern, but it would be the one way delivery of such a electric machine to the orbit of Mars and the desire to repurpose 100% of it to the surface of Mars. 100% is aspirational.

Components that may be easily repurposed would be solar panels, which are desired to manufacture Starship propellants among other things. The Argon Tanks, may be of some use on the ground. Other parts are a bit more sketchy.

If I understand the intentioned method of using Starship for visits to Mars, ~26 months, is the time window. This then leaves the Starship idle on the Martian surface with little work to do, during a considerable stretch of time.

However if you could deliver a constant stream of electric powered craft of the sort I have suggested in this post previously, then the Starship(s) could work during much of that time fetching things from the orbit of Mars. This may put crew in added danger, but Mars is a danger mission as it is anyway, isn't it?

The advantages to this is of course you are using the solar panels intended for use on the surface of Mars to help those solar panels get to the orbit of Mars. Electric propulsion may be a bit more efficient anyway.

And you may try to use the dreaded evil Ballistic capture for the electric machines.
https://en.wikipedia.org/wiki/Ballistic_capture

The reader should maintain awareness, that in this method the ~26 month window pretty much does not apply.

Yet with patience there could be even another proven method to use the solar panels to aerobrake in the upper atmosphere of Mars.

Here is a sort of example about how that is done. It is tricky stuff, but going to Mars is tricky stuff anyway.

https://mars.nasa.gov/msp98/orbiter/aerobrake.html

Done.

Last edited by Void (2020-05-29 21:24:07)

Void · 2020-06-05 07:57:39

This could be applied to the intentions of the previous post #402:
This drive only works to go from Earth/Moon to Mars/Phobos/Demos and beyond. It cannot push a load towards the sun:
https://www.centauri-dreams.org/2017/12 … nd-beyond/
Quote:

The Plasma Magnet Drive: A Simple, Cheap Drive for the Solar System and Beyond
Suppose I told you that a device you could make yourself would be a more energy efficient space drive than an ion engine with a far better thrust to weight ratio? Fantasy? No!
Such a drive exists. Called the plasma magnet, it is a development of the magnetic sail but with orders of magnitude less mass and a performance that offers, with constant supplied power, constant acceleration regardless of its distance from the sun.

Developed by John Slough and others [5, 6], the plasma magnet drive has been validated by experimental results in a vacuum chamber and was a NIAC phase 1 project in the mid-2000s [6]. The drive works by initially creating a rotating magnetic field that in turns traps and entrains the charged solar wind to create a large diameter ring current, inducing a large scale magnetosphere. The drive coils of the reference design are small, about 10 centimeters in diameter. With 10 kW of electric power, the magnetosphere expands to about 30 kilometers in diameter at 1 AU, with enough magnetic force to deflect the solar wind pressure of about 1 nPa (1 nN/m2) which produces a thrust in the direction of the wind of about 1 newton (1N). Thrust is transmitted to the device by the magnetic fields, just as with the coupling of rotation in an electric motor (figure 2).

The engine is little more than 2 pairs of charged rotating coils and is therefore extremely simple and inexpensive. The mass of the reference engine is about 10 kg. Table 1 shows that the plasma magnet has an order higher thrust to weight ratio than an ion engine and 2 orders better than a solar sail. However, as the plasma magnet requires a power source, like the ion engine, the comparison to the solar sail should be made when the power supply is added, reducing is performance to a 10-fold improvement. [ A solar PV array of contemporary technology requires about 10 kg/kW, so the appropriate thrust/mass ratio of the plasma magnet is about 1 order of magnitude better than a solar sail at 1 AU]

I regard this as a really good deal. The article is a good read.

Like it or not even at 1 million inhabitants on Mars, the workforce might be better utilized doing things other than manufacturing solar panels on Mars, if solar panels of high quality can be exported to them from the Earth/Moon subsystem. I am going to assert that that will probably be true. It would however be wise to prepare the Martians to be able to manufacture their own solar panels, if somehow for some reason this export to them would cease.

If this thing works as I think I understand, arrays of foldable solar panels could be lifted either from the Earth or Moon, by chemical rockets. The propulsion device and it's AI, would likely have been recycled back from Mars/Phobos/Demos, by a vessel returning from Mars. That propulsion device is described as rather light weight. I would think that the propulsion device would be manufactured with a high quality, as I would expect it to have a very long service life.

So, for the most part, the solar panel arrays, would fly themselves to Mars/Phobos/Demos. With a rather lightweight propulsion and navigation method.

To enter the Martian Hill Sphere, Ballistic Capture would be used.

https://en.wikipedia.org/wiki/Ballistic_capture

Mars does not have a unified Magnetosphere, so I am expecting that this thing could travel down to the edge of the Martian atmosphere, or to Phobos, or Demos.

Careful air braking could be used in the upper Martian atmosphere, but I really think it is not worth bothering with.

Getting the Solar Panels from the Moon seems like it might be ideal, because the Moon is exposed to the solar wind, and the Hill Sphere of the Moon of course is much less than that of the Earth. We could hope for manufacturing facilities on the Moon largely operated remotely from Earth, from a Lunar Gateway (With healthy levels of synthetic gravity), with just a few humans involved on the surface of the Moon. Of course AI would also be used to the extent that it was productive to do so.

I feel that this would really open up all three Martian worlds to the human race.

Of course for Mars itself the solar panel array would have to be folded back up, and put into a cargo hold of a ship capable of carrying it to the surface of Mars. Starship obviously should be able to do that.

This then addresses a concern of Dr. Zubrin, where Starships landed on Mars would sit idle and sometimes useless on the surface of Mars.

As far as I am aware, these delivery methods to Low Martian Orbit, would not have a 26 month timing constraint, so continuous deliveries could occur, some arrays going to Mars itself, some going to Phobos, and some to Demos.

This would free up cargo space for Starships, traveling to Mars, so that other items such as needed to manufacture propellant, could be carried in a greater bulk instead.

I feel that in that case, the ability to manufacture Methane and Oxygen on the surface of Mars could be greatly amplified.

Other manufacturing could also be greatly expanded under this type of situation I should think.

Kilopower Reactors:
https://en.wikipedia.org/wiki/Kilopower

These could be used for the propulsion, but I think it would be hard to get them safely down to Mars after they were turned on. Not so for Phobos and Demos. I think they could be placed into a bin attached to the surface of Phobos and Demos and hooked up with automation/robots.

Maybe the same for Mars, but probably much harder.

Methods of chemosynthesis which I believe would eventually be perfected to reasonably appetizing foods would be strongly augmented by having a much larger power supply, which would be available from the methods of this post.

Here is a start:
https://www.smithsonianmag.com/innovati … 180964474/

Combine that with 3D printing for texture, and some methods of flavoring, and this could greatly reduce the quantity of greenhouses, or Pink light gardens needed.

But also having that much electrical power would make pink light gardens much more practical, so you could have good vegetables as well.
So protein from chemosynthesis, and vegetables from pink light gardens, and food needs may be rather well addressed, without needing to build big glass greenhouses.

Instead glass structures if they are to be built, might be for other purposes, such as human happiness. The "gorge" thinking of Louis comes to mind.

So, I really think that something like what is in this post could well be the way to go, for the most part.

------

I have also wondered about associating a device like the Starship directly with the magnetic solar wind drive.

I have wondered if the Magnetosphere might also have radiation protection capabilities. I don't know at this point.

Logically if you were to transfer cargo to Mars, you would attach it to the magnetic solar wind drive device, and not carry the cargo in a starship. Then the cargo could be retrieved from Martian orbit by cargo starships.

But what about people? A Starship will be a life support system for them, maybe the magnetic drive would protect them through much of the journey to Mars???

With this method, then Starship needs less propellant, so the tanks would not have to be completely filled for the trip to Mars. Possibly the method would be to refill the starship partially in LEO, and for the Starship to travel above the Earths Magnetosphere. Then to couple it with a very large solar array set with the magnetic drive device. There could be 2 alternate methods at least.

1) The Starship remains with the array, and does a ballistic capture into Martian orbit. This will lengthen the time of the trip, but if I understand correctly, a launch can happen almost any time. You do not have the 26 month period requirement. No Hohmann transfer, and an injection into the Martian atmosphere for the Starship potentially from Low Martian Orbit, instead of screaming in from interplanetary space. I kind of like this one.

In fact although typically we think that ballistic capture makes for a longer mission, that might not be true. With continuing thrust on a magnetosphere, maybe the delivery times can be cut down. That would be something!

2) It may be possible to adhere to the 26 month, timing method, providing that the combination of chemical and Magnetosphere propulsion can be correct to meet Mars at the end of the trip. In this case, I guess Starship would decouple from the array at some point in the journey, and it would do a Hohmann transfer method, but the Magnetically propelled, solar array would navigate to a ballistic capture method.

I think #1 could be preferred, if it would be possible to incorporate synthetic gravity for the passengers, during the trip.

A Starship would not have a magnetic drive to go back to Earth, so if there is any radiation protection needed, it would need to be provided by other methods for the return trip.

Because likely Starship can mostly guide itself, when it is used for a transfer asset on Mars, then instead of Crew and Passengers, you would have Crew/Maintenance people and Passengers.

This then would create more jobs for Crew/Maintenance people in the Mars/Phobos/Demos system. Many of them would stay at Mars/Phobos/Demos, so that they could maintain, the Starships that would be in use, and I suppose they might be trained to pilot a Starship in an emergency, if the AI fails.

Only a very few people would go back to Earth from Mars/Phobos/Demos.

Probably much of the maintenance would be swapping out modules sent from Earth, rather than so much detailed repairs and maintenance.
That would be more efficient.

------
It seems I am not done yet.

Having a drive that can operate continuously from outside the Earths Magnetosphere, all the way to Low Martian Orbit, it now occurs to me that you might not do a standard Ballistic Capture, you would be able to do a "Powered Ballistic Capture".

This might cut the "Dwell Time" where you might be waiting for the Martian gravity field to suck you into Martian orbit. I really don't have a precise notion of what that would be like, but it would potentially be different than a standard Ballistic Capture.

If this works, it would greatly enable missions outside of the 26 month Hohmann Transfer methods, allowing for much more flexibility.

I think I am happy.

Done

Last edited by Void (2020-06-05 09:24:20)

Void · 2020-06-11 15:36:08

I discussed this in the Louis sponsored Starship is a go topic, where I think I was polite, and did not clutter it with too much of my excessive verbiage.

Here I will speculate.

https://www.inverse.com/innovation/spac … o-the-moon

I guess I am thinking of several possible instances of Starship, not quite fitting the Martian mold as lately told.

One can indeed be a temporary or permanent laboratory in orbit.

In the temporary instance, it is a Starship more or less as expected, but only goes to LEO. A laboratory. Customers we would hope would sign up for it. Unlike the international space station, the whole thing would go up and down, in the preferred method transportable experiments and production methods would be installed in the ship.

But prior to building trust, I think if any humans are to be aboard, that would be done with the Dragon hooking up to the Starship.

We lost most people in transit through the atmosphere, so I have to think that that is were the biggest safety measures and certainties are required and desired.

A derivative of this could be a "Mission to Earth". I hate that phrase. It usually indicated that space research for other worlds would be deferred, and perhaps budgets cut in the hopes that space enthusiasts would go away and stop dreaming.

It is obvious that for this mission, while Super Heavy is required, a propellant depot is not. So this could be starting to occur prior to the perfecting of refueling research.

In this case however I am reassured, that the techniques developed to study Earth, would lead to what I want. First, upon being able to refuel in orbit, a mission to the Moon with a similar ship, equipped with similar instrumentation.

Eventually the one I really want. A "Mission to Mars/Phobos/Demos". With desired and required instrumentation.

No heat shield, no flaps, get rid of the wind countering thrusters. I would like it to stand off from the Martian moons by a short distance, and radar the heck out of both of them. Who knows, sample returns? And the same ship, I would hope would then analyze Mars itself, hopefully with better instruments than have previously been sent there.

All of this would be useful in "Breaking In" the Starship family, and to better know the three worlds we might hope to make our own.

Of course because of no heat shield, or flaps, Ballistic Capture would be the method to enter the realm of Mars orbit.

And then there could be another one for LEO. A Starship as a permanent space station in LEO. No heat shield, no flaps, etc.
I think I heard that Starship would have 1/2 the volume of the ISS. What would that be if you "Skylabed" the whole ship, the Methane tank and the Oxygen tank? Granted GW pointed out to me that those would be uninsulated tanks, so of course you would have to insulate them and add furnishings.

Just some options that I don't think are too stupid.

I am not currently thinking Starship SSTO. So, give me credit for some brain cells.

Done.

Last edited by Void (2020-06-11 16:46:48)

Void · 2020-06-13 09:26:30

I see that their are four of us here at this time. Good.

I will put this post here, although I think it may have value. This is sort of my low level stuff, but I think this item may be high level.

I am thinking about recovery from a leak such as SN4 had. While the implementation of this would as in everything add cost, I will make the point that incinerating and blowing up ~100 passengers would have much greater costs.

So, I am suggesting some sort of safety recovery method for the leak that happened. If it is any good, I am sure it could be made better.

I do not have intimate knowledge of their equipment and methods, so I must in part guess.

Actually it would simply be a Nitrogen filled sewer system. Possibly needed would be a circular wall around the base of the craft, which might be filled with cold gas Nitrogen, and then a robust drainage system.

In this case it would only be useful for Starship without the Super Heavy, because of course in the case of the use of Super Heavy, the Starship would be far from the ground. Something else will be needed for that.

It is my belief that crew and passengers should not ride to and from orbit at first, until safety measures are developed and proven for that.
I think that Dragon should be used to install crew to an already orbital Starship, in the early days, and to retrieve them to ground, in the hopes that Dragon is a safe bet.

A drainage system for a Starship, probably sub-orbital, but possibly one way to orbit, could involve a tank filled with Nitrogen gas. The hope would be that as liquid Methane drained down the sewer, Nitrogen gas would be forced up the drain. That is, if the sewer were not entirely engulfed with liquid. But maybe it would be better to discharge Nitrogen gas into the circular wall at the base of the ship.

Methane boil off could be a problem. However if the Nitrogen gas were lighter than the Methane gas, that could help. Also helping would be if the sewer system were pre-cooled so that less boil off would occur. Also, if the spill were to go to a tank, perhaps boil off could be vented to a stack remote from the ship. It may be possible that the liquid Methane collected would be pumped away to storage.

-----

For an Oxygen leak, I guess similar could be done.

But if you had a cascade where both Methane and Oxygen were leaking, then you might blow up the sewer system and loose the ship anyway.

This is where I do not know their methods of procedures.

Perhaps if the Oxygen is filled first, and disconnection lead to no leaks, then later you would then fill the Methane.

As I said, I think that not knowing what their methods are, makes it harder to figure out safety recovery methods.

Done

Last edited by Void (2020-06-13 09:38:50)

Void · 2020-06-13 13:39:27

I am going to put some materials here about power from the winds, to generate propellants for Starship and Super Heavy, and hopefully make that Carbon neutral, and perhaps to generate such for other purposes.

I believe that I have posted something like this before, but I feel it is a good item.

Basically it involves sailing ships, and the means to generate power to create propellants.

I believe that the ocean has a great deal of CO2, so degassing the water, will provide that. And the water is water, you just distill it. And by the way possibly deliver water to shore periodically.

If you have a way to propel a ship with a propeller setup, you can perhaps also make it a turbine. Drag the ship through water with sails, and generate electricity. As you would have propellants on the ship, perhaps the same turbine blade used at times to propel the ship, when the winds are not favorable.

And here might suggest another method:
https://en.wikipedia.org/wiki/Yamato_1

In addition, it might be possible to use methods similar to OTEC.
https://en.wikipedia.org/wiki/Ocean_the … conversion

Where OTEC is stationary, and "Lives" in a equatorial band of low winds, this could occupy more turbulent places. Scooping warm water from the surface, and using the ships bottom for a heat sink. Possibly lowering a portion of itself when underway, to lower and colder locations.

This could be advantageous for distilling water. In this case, I would not think to generate power from thermal differences, but to facilitate distillation and other processes such as sucking CO2 out of the water to be distilled.

Some such devices can recycle heat.

But in this case perhaps, suck steam and CO2 from the warm water with a forced vacuum.

Then compress the steam to generate condensate. The heat from this compression process can be rerouted to the warm input water, but also, the relatively cool bottom of the ship could also facilitate condensation. I guess best practices would be discovered.

And that's enough I think.

As it appears that eventually the launch pads for at least some Starships will be offshore, it should not be that hard to offload products to those locations, possibly then pumping the water through a pipeline to shore(s).

And that then connects this process to the Starship topic.

Done

Last edited by Void (2020-06-13 13:54:14)

Void · 2020-06-15 18:30:21

This apparently is my day to post like crazy.

I am thinking about what O.F. 1939 calls "Deep Space Starship", a good name I think.

They are thinking about more usable legs for it to land on rough surfaces. If some of them were to carry crew, then I would think they would have to have that as I suspect it would be pointed out to me that they might not make it to a landing pad.

But for cargo deliveries, I am thinking about using landing pads as part of the landing gear, until there are enough landing pads.

If the landing pads could be made of metal, then they could be unfolded or assembled into something strong enough and broad enough to land on. But such pads then might be assembled at the ISS, and then attached to the outside of a Deep Space Starship. It might be possible that they would even serve as landing legs for the starship that delivers them. It would also make the center of gravity lower.

If the starship were to stay for a long time, then the starship might be later secured with anchors and cables, and then the landing pads dragged away for use at a greater distance.

Then some starships could land on them, with less robust landing gear. You get a lot of extra permissions if you don't have to travel the atmosphere of a planet or moon.

It may even be possible to secure extra cargo to the landing pad legs, if the ship could manage the extra weight in landing. And then this would further lower the center of gravity.

But I maintain the opinion that crewed missions should have robust landing gear built in, in case of missing the pad.

Done

Last edited by Void (2020-06-15 18:42:08)

Void · 2020-06-15 19:12:57

By the way, they seem to be pressure testing SN7, a test tank today.

------

Building on the last post then, #407, more has come to mind.

It seems to me that you cold divide Deep Space Starship into two general types. Cargo, unpressurized, and Crew Pressurized.

The Crew version, could have either of two types of landing gear. As I mentioned landing pads as landing gear, and where cargo might also be tied down to the landing pad/landing legs. Then such a lander could have things like carts on the landing pad/landing gear. This might be done if, it is intended that these crew ships would stay on the Moon for a time, to serve as the early base. It would be necessary to pay the expense of real storm shelter radiation protection in these.

The tractors on the landing pads could then drag the landing pads to somewhere else for future Starships to prefer to land on. In order to do that however there would need to be a method to brace the ship upright when the landing pads were taken away. Perhaps one method could be to retain one landing pad as connected, and pile regolith on top of it. That could be a partial solution. Maybe need additional structure as well.

The crew Starship/Moon shelter, would not have much internal cargo space. And by this method, if it is desired, it might be possible to put it back into service later as a rocket ship.

And if it is then desired to have dedicated cargo ships, then there would be landing pads for them. If a good track record is established, maybe not too many of them would be lost in toppling.

Done

Not Done

Last edited by Void (2020-06-15 19:22:02)

Void · 2020-06-15 19:24:26

This continues post #405:

I am thinking that for Starship suborbital, a plan could be improved.

Similar could be done for Super Heavy.

How to fix a leak on a Starship mounted on a Super Heavy, I don't have a plan for that at this time.

But if Super Heavy blows up, then you do loose the Starship as well, almost certainly.

A partial solution would be to have a spill basin, but this time divided in half with a wall between the parts. Add the Oxygen 180 degrees away from where you add the Methane. Two separate sewer systems. It is unlikely that you would leak both Oxygen and Methane at the same time, but Murphy's Law, don't you know.

In all cases you would want a flame suppression method such as Nitrogen covering the spill, maybe somehow CO2, and maybe Halon Gas (That's expensive).

Prayers also.

If the ship itself leaks both Oxygen and Methane and they spill into each other, then good by.

I think it suggests improvements of odds though.

Getting rid of ignition sources also a good idea.

Done.

Last edited by Void (2020-06-15 19:30:05)

Void · 2020-06-16 08:12:59

I appropriated this from Louis, Starship is a go, #715.
https://www.youtube.com/watch?v=cC6JiuTCG6Q

I am going to play speculation fool here, so if you are a rocket man, perhaps wear a mouth guard in case you grind your teeth.

1) Super Heavy to orbit.
2) Could a sea level engine transition to a vacuum engine in flight with a bell extender?

For #1, Looking at the Moon version, "Deep Space Starship", could the Super Heavy go to orbit. Of course the other question is "Why"?

It has been said that a stripped down Starship with no payload, and no ability to land on Earth or Mars, could just possibly go SSTO. But for the most part it is agreed that it is almost certainly a useless potential capability.

If Super Heavy were to go to orbit, I would have a hard time finding a purpose for that. But you never know maybe some day, far down the line a purpose could be found.

First I am going to say a nose cone is needed, which adds weight. But since a Starship will not be stacked on it in the Earth's gravitational field, it should be possible to lighten up it's structure. I am supposing that Super Heavy has to have extra structure to bear it's own weight and that of a Starship stacked and filled with propellants, and payload. So, likely a very serious weight reduction possible if it is to be SSTO.

As I have said, I lack a strong purpose for this. A moon lander? Then you have to add weight by having special landing engines.

I believe the real Super Heavy can get by with as few as 20 engines. So that is a weight reduction. I don't know how many engines a modified Super Heavy SSTO would need. 4 or 5? It would be lifting much less, but you would want a much longer burn to achieve orbit.

So seriously reducing number of engines would reduce weight and complexity.

You could get rid of the landing legs, that would reduce weight. And there already would be little or none for a heat shield, I presume.

-----

Now for engine bell extenders.

One possibility would be to have a bell outside of the sea level bell, that when retracted surrounds the sea level bell. It would have a hole in it where the "Cone" part would be. Two problems. Something needs to push it out in flight so that it's upper perimeter mates with the lower perimeter of the sea level bell. Also, it needs cooling.

It would be tricky to have propellant lines that were flexible to allow for cooling with propellant. So, I am thinking active cooling with water or Methane. In the case of Methane, since that might be added to the rocket exhaust, the main engine would be wanted to add more Oxygen. In the case of water, it is just bleeding water into the interior of the extended bell.

Another question what happens when the outer bell is in mid way extended? Could you get away with modulating extension? If not fully extended, does the plume do nasty things, such as blow you up?

-----

Another possibility in imagination, if not reality, would be bell extensions on hinges where they would be like petals on a flower. Pulled away from the engine at sea level, and then pushed downward to envelop the plume to make the engine closer to suitable for lower pressures? Probably actively cooled again.

I know it is probable that someone has considered the ideas previously, and rejected them for a good reason. But these could be things worth learning about.

Even if the active cooling method with water were just a poor quality of thrust steam engine, they would be recovering heat that would have radiated away from the plume in many directions.

And making things more complicated does carry penalties, I understand.

-----
Oh, and back to Super Heavy:

I wonder about adding basket legs to it in LEO. The Super Heavy has no cargo bay. But if you could carry them to orbit, say in a Starship Normal, you could have external cargo bays, probably unpressurized, and also serving as wide stance legs/feet for that Super Heavy, if it was to be used to take payload somewhere, maybe even the Moon. Of course the payload would also have to be brought up in a Normal Starship.

And the nose cone on this assembly might be a unpressurized cargo bay, or it could be gotten rid of I would think. This thing would never travel through atmosphere again.

Done

Last edited by Void (2020-06-16 08:44:05)

tahanson43206 · 2020-06-16 09:40:36

For Void re #410

You have probably been following GW Johnson's writings closely as have I.

You will no doubt have noticed his proposal for an expedition plan for Mars that would depend entirely upon supplies from Earth for the safe return of the crew.

As you may recall, GW Johnson's plan envisions a large, capacious, comfortable "mother ship" from which landers would depart and to which they would return.

Such a vehicle would be constructed on orbit.

Thus, I am intrigued by your vision of a Super Heavy that lifts itself empty to orbit.

A deep space "mother ship" could be assembled from a number of these.

GW Johnson's vision included artificial gravity for the crew, and radiation protection against solar bursts.

Your imagination may well be up to the challenge of visualizing how a number of empty Super Heavy vehicles could be assembled to meet the requirements of such a mission.

It should be noted that the huge vessel would have to launch itself from LEO and stop for a matching orbit at Mars, and then launch itself from Mars and match orbit with the Earth. For those tasks, the engines of the empty super heavy vehicles would seem well suited.

This is a bit of a stretch, even for your imagination, but suppose the engines were fitted with deep space bells from the outset?

There would be a penalty of reduced efficiency at launch from Earth, but they would have to do that only once.

(th)

Void · 2020-06-16 10:21:23

Well, that could be possible. In the beginning, SpaceX was toying with hybrid engines, that could do sea level and vacuum, but with performance losses. But what you suggest, I think, might allow for that to get to orbit. You would only do it once. Then in LEO, maybe put a bell extension, or perhaps even better change out the bells to be for vacuum.

However, although you would only do it one time, at this time it would call for EVA's in suits, which will always risk people, and add expense.

I know that G.W. does not think much for Aerocapture to Mars orbit, probably for good reasons. You would need all the gear for that which would add expense, more parts to fail, and lots of weight.

The purists never seem to rise to the bait, per Ballistic Capture, but it could be a solution. In that process, it is possible to enter Martian orbit without a serious engine burn. From what I read, however eventually you would go back out into deep space, so upon being in the gravity well of Mars, then you have to run the engines to some extent to make the orbit permanent.

https://en.wikipedia.org/wiki/Ballistic_capture

I know that at this time Elon Musk does not think much of Ion drives, and probably not electro-magnetic drives. NASA, however does have the notion of electric ion drives.

To do ballistic capture, a penalty, is a longer travel time of a extra month or two. All that time being susceptible to space dangers. If no crew, or passengers, just cargo, then so, what? One benefit to Ballistic Capture is you are not constrained by a 26 month launch window. There apparently are many opportunities to launch, perhaps many of them are not fuel efficient though. I am not sure.

In the case where you did have crew and passengers and had synthetic gravity, a longer travel time is less dangerous, but you still have radiation dangers, and the expanded potential for equipment failure while in deep space.

In a dream world, I would hope to add a magnetic propulsion method, which would also provide extra radiation protection to a degree. Not for GCR though.

I have presented this one a few times before. I have problems wrapping my mind around it's scale of size though.

From what I have read it might be good for cycling spaceships, although that is not what I am after.
It could provide magnetic shielding from solar radiation dangers.
It also provides propulsion from the solar wind in Earth>Mars, but not Mars>Earth.

------

So if this abomination (not really ) were to go Earth high orbit>Mars Ballistic Capture, then:
You would have both chemical and Solar Wind propulsion.
Radiation protection.
Potential for Ballistic Capture.

You would want lots of solar panels. Many of those would be left behind for a air adapted Starship to take down to Mars.

On your way back Mars>Earth, you could not increase speed with the magnetic propulsion. But the ship would be lighter, because presumably you left a lot of gear behind in Martian orbit. So, you need less propulsion capability.

Still if you had enough electrical power, you might still use the magnetic drive as a sort of magnetic parachute to modify your orbit.

Upon reaching Earth/Moon, you could not do an aero-capture. I don't know if you could do ballistic capture that way to Earth. But you would have the magnetic parachute to slow you down, and to alter your course with. And then even if no ballistic capture, perhaps the magnetic drive does enough for your situation so that you don't have to burn that much fuel to get into a high Earth/Moon orbit.

Then you could use the magnetic drive as both propulsion on part of an orbit of Earth, and as drag in another part of orbit, to get as far down as near the Earth magnetic domain.

Food for the imagination, not assured to be practical.

------

Another silly thought pops to mind. I am pretty sure it is not useful to do a gravity assist to launch from Earth to Moon. But upon return to an initial very high orbit, maybe it would be possible to do a Lunar gravity assist to help get to a lower orbit. So you would have three propulsion methods, (If that would help). Chemical, magnetic solar wind, and Lunar gravity assist. You could actually get rather close to the Moon, I think, 50 miles? Maybe less. But I don't know what would be best.

Most likely there would be no crew or passengers on the return trip, if returning people would instead use a Starship.

But I confess this is just talk, and perhaps silly talk at that. I had fun with it though.

It just keeps on:

I wonder if that magnetic field would both protect to some extent from the Earths radiation belts in the magnetic field, and I also wonder, if it could slow you down also like a parachute while within the Earth's magnetic field. If so then you could get it down to LEO, mostly with magnetic drag.

Done.

Last edited by Void (2020-06-16 10:52:00)

Void · 2020-06-18 10:32:01

SpaceX is apparently beginning to plan for floating rocket bases.
https://www.businessinsider.com/elon-mu … ing-2020-6
I mention it here because I am going to think weird about it.

Here is some somewhat related material from Scott Manley:
https://www.bing.com/videos/search?q=Sc … M%3DHDRSC3

It appears more likely, that these will be stationary like an oil rig. That would be helpful, if you wanted to connect undersea utilities from the land. Oxygen??? Maybe not. Methane, maybe yes. Electricity, I guess it is possible, using technology similar to that for off shore windmills.

-----

I am not necessarily saying I know what SpaceX could or should do. But I wonder about Hurricanes. Maybe the platforms are so big that they can take it.

But I am going to presume a platform anchored to the sea bed, and utilities to it from land. However, I will suggest that it not emerge about the water. And then a floating platform/ship, may moor to it and connect up to the utilities. And I am not saying that this is what SpaceX or anyone else will actually do. I am trying to set up for something bizarre.

From Scott Manley's video, I could suggest that actually the Earth is the first stage, and Super Heavy would be the Second stage, and of course Starship, is the 3rd stage. If it is looked at in that manner, the first stage is sort of horizontal propulsion with a rather small contribution the path(s) to orbit(s).

If the floating platforms of SpaceX were at the equator, in the doldrums, the maximum possible benefit would be available.
But, the North American infrastructure suggests that it would be better to be off the coast of some place like Texas, as the equator is remote from what is needed otherwise. As I have said, perhaps the floating platforms are so big that they will be just fine. Of course you could not launch in such storms.

For passenger service, sub-orbital, I guess you might just grit your teeth and live with it.

For platforms to launch cargo or propellants, perhaps you would relocate the floating portion to another place in the ocean where the weather was not so bad. Doldrums?

Presumably submerged tower platforms off of a coast where Hurricanes would not be much of a problem.

------

Brace yourselves, I am really going to get weird. I justify myself, because space elevators from Earth are also really weird, so cut me some slack. This may not be as weird as those.

What if we made a Rocket Ship? That is a ship that is a rocket? A horizontal rocket.

Normally you can't get a ship up to much speed. If you put bubble lubrication under them you can get a bit faster, and a bit more efficient perhaps.
https://www.marineinsight.com/green-shi … hips-work/

That is useful for a long distance runner profile. But I want a "Blue Dragon Fire Breathing Sprinter".

So, to start with just normal ship propulsion maxed out, and bubble lubrication. In the doldrums, it is possible that wave action will be subdued at times and facilitate a small contribution to getting Starship to orbit. Perhaps not worth the trouble really.

But I want much more.

OK, the ship traveling has to push on water as it moves forward. I want a trench digger, so a trench can be dug ahead of the ship, to perhaps allow for more speed.

For now, I am imaging Raptor engines to do this. One on the front of the ship, pushing water out of the way, and unfortunately pushing the ship backwards. So, then put another raptor on the back of the ship, to nullify that force on the ship.

So, you may have been able to cut a trench for the ship to travel with greater ease than pushing the Ocean out of the way.
Perhaps your ship can go faster.

Obviously to avoid scalding, people must be put into protective structure.

Now I want better lubrication. Rather than air bubbles, I want a continuous air film all around the ship. So, although I fear a raptor engine would be too aggressive, we point one down into the water from the ships bow. We then hope to have a ship floating on a film of air, the air floating on water.

But this could go terribly wrong. If you mixed a lot of bubbles into the water, at significantly lower layers, you might loose the ships buoyancy. It could sink very quickly. So, it is a thing to craft with precision. Much study needed.

But we are still not happy with our sprint speed, so we put a bunch more raptors on the stern of the ship. Insanity follows.

I believe that a hydroplane can go to 300 mph. And it is dangerous also if you hit a wave. But we have a trenching tool on the front of the ship.

And I did say sprint. Maybe this only runs for less than a minute.

-----

Certainly there will be cost. But advantage? Not sure. I guess if you get a couple extra tons to orbit with the same stack, that might be worth $$$.

-----

Now the Raptors, Perhaps too aggressive, especially for the engine that points down.

I am wondering about a liquid air engine, instead of liquid Oxygen. We don't actually have to rise above the surface, so that might do.
That way then, their is more mass throughput.

But if even that is not the deal, I suppose compressed air could be used for the down thruster at the bow, which pushes an air envelope around the entirety of the ships bottom.

Jet engines? Maybe.

-----

Well, that's it for now. It might make a good cartoon, or video game. Idiots might try to use it as a sadistic weapon.
But maybe it could have merit.

At least I tried as I flew over to coocoo nest.

Done

Last edited by Void (2020-06-18 11:25:42)

Void · 2020-06-20 11:35:08

So, I will give it a try.

Observing all of the tank failures in the SpaceX testing, I think I have become aware of a few things.

SpaceX appears to be heading in the direction of a planed leak, which makes sense since a burst will be so much harder to handle. Almost certainly leading to a sequence of disassembly of the whole ship, and probably the launch pad. I suppose if the spill is small, it might be handled by sewers, and ignition suppression, and also isolating the spill from what it might react chemically with.

I am beginning to like inflated balloon tanks, because I think there may be a way to make it safer. For instances where humans are vulnerable, however, I would head in the direction of stoutness and safety overkill.

So, I think that cargo launches will possibly involve inflatable balloon tanks.

What I have in mind, to get to it is extendable stilts with strain gages, to measure the load they are holding against the Earth's gravity.

I am looking at a pin and socket mating, on the perimeters between tanks, and perhaps the perimeter of the top of the Super Heavy. Maybe even for the Starship itself, but that gets more complicated.

Start with a tripod of hydraulic stilts the mate to sockets at those locations. Of course they have to be made so that they do not cause damage to the ship.

I don't believe that in the beginning of the Atlas program, such capabilities could exist. But cranes say to me that it could exist.

It is even conceivable that if the Super Heavy suddenly disappeared, depending on your method, the Starship could either evacuate passengers, or launch to a hop.

In reality though the Super Heavy would not simply disappear, but be in great danger of a massive explosion.

So, you have had a problem with a tank. These stilts, may control the situation to a degree, while you try to mitigate the dangers.

Of course, the stilts are an added expense, but perhaps not expensive as a massive explosion which takes out the whole rocket, the passengers, (If any), and the launch pad as well.

The stilts will have to retract appropriately, and also withstand the rockets hot blast. And as I said before, they must not poke holes in the tanks.

As for the sockets. These may present trouble. I think it might not be too hard to cover that for the Super Heavy. If needed, spring loaded doors????

For the Starship, while the ones on the leeward side might be similarly handled and protected. I would think that poking a hole in the heat shield would only be done in a launch abort situation. Repairs required.

The stilts should also be useful in high winds. We remember that Star Hopper lost it's nose in a topple from wind.

So, the stilts would possibly prevent a catastrophic cascade destruction event, particularly if a lowest tank ruptures and looses pressure.

They may also make it possible to minimize the structure for Super Heavy, and maybe even Starship, for materials launching. If this is demonstrated, it may be that less structure is needed to operate safely, and more payload can go to orbit.

Going traveling again today.

Done.

Last edited by Void (2020-06-20 11:50:39)

Void · 2020-06-21 09:36:08

Overnight, I came up with what I think is a better design.

Say perhaps three vertical towers like a radio tower, with the pins in them. It would probably need appropriate mechanism to mate them with the rocket body, and unmated them when appropriate. Also to get them protected from rocket blast after un-mating.

The sockets on the rocket body would have spring loaded doors that would open with pressure from the pins, and close again upon removal.

And yes, there is a sort of bi-gender nature to this. Nature often knows best. Not shy about that at all.

So, I don't know if SN4, was what you could consider a "Balloon tanks" situation, but it sure looked like it. My hope is that with at least 3 towers that can serve as hangers for at least the 1st stage, and with methods to handle the spill, and perhaps prevent the ignition, the collapse of the rocket would be prevented, and the cascade explosive event would not have occurred.

And I am thinking that such rocket hanging apparatus would indeed allow for less structure on the 1st stage, at least, in the case where human space flight is not included in the proposed launch. And so more mass to orbit, I would hope.

My awareness of metal balloon tanks has come to me from other members on this site. As I have learned, when pressurized they are strong. If they loose pressure in an unscheduled moment, they will collapse. My hope is that using the pins and sockets method may allow recovery from such a depressurization event, and make balloon tanks more trustworthy.

Done.

Last edited by Void (2020-06-21 09:49:50)

Void · 2020-06-23 10:18:10

From Mars Analog Research Station:
From (th)
From the (th) post #27

Quote:

For SpaceNut re Davis Station article .... Thanks for posting that ... I found it helpful in thinking about the selection process for leadership.
The woman who won the leadership post competed with 13 men. I suspect they were ALL highly qualified, so the selection committee were looking for qualities that were highly unusual in the human population.
I would think Ms. Roberston would be someone who would be consulted with close attention, if a group decides to fund an expedition to Mars.
The trip will be longer, and the dangers even more extreme, but the human dynamics are quite likely (in my view) to be similar.
For Louis ... while your observation about zero gravity is important for the subject of the effects of isolation, that was not a feature of the experience reported.
The impact of isolation in ** this ** case was the absence of influx of new biological stressors. Zero gravity would be in addition, were it allowed to occur, which I certainly hope will not be the case.
The funding agency should (in opinion) pony up for a full 1 G environment for the trip to and from Mars, or just forget about trying to make the trip.
GW Johnson has made that point multiple times, as have many others.
(th)
Rachael Roberston is an international speaker and author. Her latest book is Respect Trumps Harmony: Why Being Liked Is Overrated and Constructive Conflict Gets Results.

Last edited by Void (2020-06-23 10:21:56)

Void · 2020-06-23 10:22:45

(th),

I am only rendering an alternate view, and not necessarily a more correct view.

NASA has done a lot of good work, but their priorities seem to exclude research in space itself of spin gravity.

SpaceX/Musk, have a major set of priorities such as reaching and returning from orbit, developing Lunar capabilities, and then to at the very minimum be able to land a Starship on Mars, ASAP. I don't think they will divert for Spin Gravity any time soon either.

But on the relative cheep, I think we could get approximate data on low forces biology by piggy-backing on the Moon effort.

Frankly, I don't even want to see 1g gravity simulation in space at this time. I want to gather data on human biology exposed to intermediate forces, methods to use the existing Lunar gravity for that + Other methods on the Moon. This could give us the least expensive path to study Lunar effects and (Lunar effects + Forces from Machines) = ~Mars forces.

Machines can be weights, springs, other mechanisms.

So, actual Lunar effects.

And ~Martian simulation. To be compact, the weights could be of a heavy metal. Bulkier would be armor made of something that better stops radiation. Perhaps water, perhaps paraffin wax, maybe water. Awkward for sure, but very useful research.

You would be testing and toning Muscles at some simulation of ~.38 g by the combination. Same for the bones. Most other things like eyes would be at 1/6 g. Blood chemistry, body chemistry, immunity? Well since you would have a variance between two sets of people, the ones who use Moon gravity only, and another group who would use Moon gravity + Mechanical forces, in particular, I think you could tease out some important information. Some surprises perhaps. That is, for instance, if blood/body chemistry are affected differently between the two groups. And if that difference overflows into things like Muscle and Bone, and eyes, ect.

The ideal would be to find the sufficient amount of in flight, (Simulated on the Moon), therapeutic treatments, for the least effort and cost.

And also to get an idea of what being in the Martian force, (Pure Gravity), will do to the human body over significant periods of time.

A 1 g simulation, would leave us short of the needed knowledge about those things.

And so, that an added reason to have people living on the Moon----Soon.

-----

I am thinking of something like a life preserver, cloth outside, and inside lead sinkers embedded in paraffin wax. Leg sections also. Helmet? Granted, not a fabulous amount of radiation protection, but some, and it also serves to weight the body down in the 1/6 gravity on the Moon. But gonna be bulky. Also per inertia some worries for the neck being snapped, (whiplash?), if a very heavy helmet. Some protective invention needed for that to be solved.

Done

Last edited by Void (2020-06-23 10:56:28)

tahanson43206 · 2020-06-23 12:36:26

For void ... thank you for carrying the observations from the Antarctic research station into your topic here, and developing them in interesting new directions. I applaud your interest in research about gravitational influence on the well-being of living things, and hope you will find ways to (somehow) encourage funding for such research.

Design of an expedition to Mars (or anywhere away from Earth) is another matter entirely, where research must be collapsed into decisions.

The overriding conclusion I have seen expressed on multiple occasions by multiple people is that (in the absence of such research as you have advocated) the wise course for mission planners is to design for 1 G substitution, as well as other measures for the protection and safe return of the crew.

(th)

Last edited by tahanson43206 (2020-06-23 12:36:53)

Void · 2020-06-24 19:20:25

I would like something like Zeus or even better a pack of them to be on the Moon, and to periodically, randomly howl at the Earth with radio waves.

https://spaceexplored.com/2020/06/17/sp … -starship/

And they should have the mouth/hand fixtures pointed at the Earth.

Pictures and videos of it as well.

Done

Last edited by Void (2020-06-24 19:22:46)

Void · 2020-06-25 17:03:15

I think that eventually something like this could work for the likes of Super Heavy and Starship.

For now though, I think they are close to "Good Enough" with the directions they are taking.

But someday perhaps, ……………….
https://phys.org/news/2020-06-strong-du … itive.html
Quote:

Strong and ductile Damascus steels by additive manufacturing

Done.

Void · 2020-07-14 04:17:36

OK, I am up to silly trick proposals again.

Was a bit sad to have a reality check from GW Johnson. I want it, and need it, but want to wiggle out of it.
So, from GW Johnson, "Index» Human missions» Starship is Go...", post #758,
Quote:

In post 751, Oldfart1939 said:
"I seem to recall Elon making a comment (on Reddit?) about the Lunar Starships being a one way mission for freight hauling? Then could be used as habitats for the astronauts. These could be cheaper to build since they would be one way transport systems carrying heavy load of supplies."
I think I understand why Musk said that. In the last few weeks I have used my reverse-engineering results for Starship / Superheavy to quantify expected performance for lunar missions. Despite the growth from 1100 tons to 1200 tons of propellant, the growth from 85 to 120 tons of inert structure has just killed direct moon landings with Starship, except for one-way strandings there. Growth in inerts affects mass ratio far more strongly than growth in propellant. That affects delta-vee capability, and quite adversely.
I'm still showing two-way trip capability to Mars, using local refilling on Mars to come home. But the payloads aren't as large as I found in 2019 and earlier. I'm still showing very respectable performance to LEO, but again, for 2020, payloads are smaller.
But for the moon, two-way unrefilled travel is infeasible with the 2020 data, and there is just no way around that conclusion. I did find a couple of ways to send big payloads to the moon with the 2020 characteristics, but these require send tankers to LLO and refilling the cargo Starship in LLO, either before or after making the landing.
All this is posted over at my "exrocketman" blog site, under the title "Non-Direct to the Moon with 2020 Starship" dated 7-13-2020 (looking at the refueling-in-LLO scenarios), and "2020 Estimates for Spacex's Starship to the Moon" dated 7-5-2020 (examining the direct unrefueled landing scenario).
Beyond that, I am now entering official geezer status tomorrow, when I officially turn 70.
GW
Last edited by GW Johnson (Yesterday 22:37:15)
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
Offline

OK, I am aware of intentions by SpaceX to replace the Falcon 9 1st stage with Super Heavy. (More or less).
I also am aware that at least at this time SpaceX does not want to bother with a "Mini-Starship".

I also confess as you already know that I am a kluge at these sorts of things, and am not likely to do the fine numbers, so please forgive that.

I feel it is a shame that Dragon cannot be used to access the Moon's surface and return.

However, what if you kept the Dragon and the 2nd stage of the Falcon 9 system, and lifted it to LEO in a Starship fairing?
This would be a hinged faring type Starship.
-If you want to be safe and lower the weight, you do not fuel the 2nd stage until LEO. But that is an option only.
-The fairing may serve as protection of the Dragon and 2nd stage during transit by Starship to the Moon, or the fairing might be cast off in LEO, maybe to be returned as they do for the Falcon 9 system now. Or you could cast off the fairings just before a lunar landing.

This Starship, would be a 1 way trip to the surface of the Moon. The Dragon and 2nd stage would be stacked on top of it, to get crew back off of the Moon. The Starship left there would eventually serve as habitat, if the tanks could be purged, and the interior made suitable.

Here I am without numbers. I do not know what the capabilities would be of a 2nd stage with Merlin engine would be. But, presuming they might be enough, then a return to Earth would hope for some retrieval methods.
-Perhaps it could make it to the "Hated" Lunar gateway. I would be reluctant to count on that, as I am not even sure it would exist in time.
-But if you had another Starship, capable of landing on Earth, it could go out and scoop up the Dragon, and maybe the 2nd stage as well.

The safest method might be to have it in orbit of the Moon prior to the launch of the Dragon/1st stage off of the Moon. But that costs more propellants. More dangerous would be to have it loop around the Moon and scoop up the Dragon and perhaps 2nd stage.

Both the one way to the Moon Starship and the retrieval Starship could have extra consumables.

The return Starship would then bring itself down to the Earths surface, with the Dragon and perhaps 2nd stage in it.

If you chose to leave Dragon fully capable of landing, that might serve as a lifeboat option. Or you might do that, to simply lower the weight that the Starship must land. That would probably require a very good heat shield.

But in the case where the Starship was trusted to land the Dragon, and perhaps also the 2nd stage, there would be very little wear and tear on them, (I would hope), and they would possibly be fully re-usable.

------

Down the road, it might be possible to refuel Oxygen only from the Moon, into the 2nd stage.

------

As for the landed Starship left behind on the Moon, you could also land a one way non-crewed Starship with extra resources, to make it habitable.

------

I have only done this so I can get back to sleep. But, it is a possible way to get people to the Moon earlier, then to create a full habitable 2 way Lunar Starship, and might reduce the diversion of resources from the Mars effort, and Starlink efforts.

------

Well this is where I put the weird stuff, so that I don't clutter the board and annoy the other members as much.

Sleep maybe......

Done.

No rest for the wicked I guess.

This would be going "Apollo" it seems.

I am puzzled by the Lunar Starships 9 canted small engines. I wonder what those are.

Anyway, maybe for this Lunar Starship, you could pull a Vulcan and get rid of the Raptor engines, in LEO.

And to steal another trick, you might have drop tanks added to the Starship landing stage, maybe even to the 2nd stage with a Merlin engine, if there were room in the Starship faring.

Done

Last edited by Void (2020-07-14 05:22:04)

Calliban · 2020-07-14 05:58:58

A few months back, we looked into building a steam cannon to give the BFR an initial boost to about 500m/s. The initial idea was to do away with the lower stage and dramatically cut operational costs. But this would have required either an impractically high acceleration, barrel length, or both. A 500m/s vertical boost would require a 5g acceleration over a barrel length of 2km. A 5g acceleration will not require any design changes to the lower stage, as it is within its typical acceleration range. Hence, this is way of boosting BFR payload without needing any design changes to the rocket itself.

An initial boost to 500m/s would greatly improve the propulsive efficiency of the lower stage, reduce the time spent accelerating in the lower troposphere and boost payload capacity. Something worth looking into.

Last edited by Calliban (2020-07-14 06:06:11)

tahanson43206 · 2020-07-14 07:00:28

For Calliban re #422

It is good to see you are still thinking about this interesting idea!

The parallels between your idea (as I understand it) and those of Dr. John Hunter resonate with me. As you know, Dr. Hunter envisioned a 1 km barrel set in the ocean, able to send a metric ton package (solid rocket and payload) to space, at a velocity sufficient to allow the solid fuel rocket to provide the horizontal impulse to allow the payload to achieve orbit.

It seems to me that by tweaking his idea, and blending it with yours, his idea would be given another chance at life.

You (no doubt) recall that Dr. Hunter's (planned/imagined) method of achieving the needed launch pressure for his design was to impart the necessary energy to a volume of hydrogen underneath the payload package.

Your scenario is different in interesting ways. Your boost phase is longer (2 km instead of 1) and your package mass is greater (ie, hundreds of tons), but hydrogen could care less how it is being used.

A concern I would have (if I were thinking about funding your project) is that the walls of the launch tube are going to be experiencing significant stress.

However, we have an advantage in this situation that would NOT apply if I were trying to talk to Dr. Hunter. Hopefully, ** you ** will be willing to respond to the invitation to develop your ideas a bit further.

The happy result that ** might ** occur is that Dr. Hunter might be interested, and thus willing to explain how he was planning to inject energy into the volume of Hydrogen at the bottom of his design.

In the present instance, energy needs to be injected steadily over a significant period of time, so as to insure a smooth acceleration of the massive chemical rocket in the barrel.

Other little details about methodology will fall out of development of your idea ... for example, the method of loading will be of interest.

I would expect invention to happen, as the prospect of lowering a multi-ton vehicle loaded with fuel and oxidizer into a barrel confronts the designer.

Still, this new concept promises to add some major energy to Void's topic!

Edit#1 .... The concept under discussion here might become recognizable to a larger audience with the title: Space Escalator

Space Elevator is more appropriate, but that term has been pretty well appropriated.

The term "escalator" is associated with a moving belt (chain) rather than a single massive push.

Perhaps there is a better term more suitable to capture the essence of Calliban's idea?

Edit#2 ... ? Piston ? .... if Calliban's idea is developed along the lines of the familiar hydraulic piston, then the loaded and fueled rocket could be set on the upper surface of the piston (at ground level) and the barrel would be located underground along with the gas pressurizing system.

? space piston ?
? launch piston ?

This subtopic started out (as I recall Calliban's text) as a reminder about the potential of steam ... Perhaps the answer here is to find a combination of chemicals (hydrogen, oxygen and moderator of some kind) to impart the needed energy to the piston in a controlled burn, similar to that of gunpowder, which burns slowly in order to deliver high pressure consistently over the flight of a bullet from rest to exit velocity.

Happily, we have at least one chemical engineer in the group.

(th)

Last edited by tahanson43206 (2020-07-14 07:24:49)

Void · 2020-07-14 08:47:33

Actually I don't think I suggested anything too exotic, in my post #421 here.
-Using existing and tested components from the Falcon 9 system. That is crew dragon, and the 2nd stage.
-The under development Starship with Superheavy. Both the Moon version for a 1 way landing, and a aerodynamic version for return.

The 2nd stage was intended to get the crew dragon back to a Lunar orbit, where the aerodynamic Starship would fetch it and take it back to Earth.

I did suggest some non-planed add on's, to improve the reach of such a system.
-Drop the Raptor engines in LEO, and then rely on the 9 small canted engines on the sides of the ship, in LEO, to reduce weight. (This is a rip-off of Vulcan plans).
-Use drop tanks as needed to add greater fuel storage. This might be applied to the 2nd Stage of Falcon 9, and also to the one way Starship.

I also mentioned that one way supply ships without a return to Earth method could be used.

This then is Apollo on Steroids. The only part I am a bit unsure of is that the 2nd stage of a Falcon 9, with 1 Merlin engine could ascend to a lunar orbit with the crew dragon on top of it. The two uncertainties are:
1) Would a single Merlin engine be able to lift off the surface of the Moon with that load.
2) Would it have enough propellants to make it up to a 50 mile high orbit for the aerodynamic starship to fetch it. So I am looking at the possibility of drop tanks for the 2nd stage, which of course then complicates #1.

This is Apollo on steroids, but with hardware mostly or completely, reusable, or repurposed.
Reusable:
-Crew Dragon.
-2nd Stage of Falcon 9 System.
-Aerodynamic Starship.
-Possibly the fairings of the one way Lunar Starship(s), hopefully the way that is done for the Falcon 9 system.
-Raptor engines. Maybe they could be extracted in LEO, and then brought back down to the Earth's surface.
Repurposed:
-One way Lunar Starships.
Disposed of:
-Probably the drop tanks would be dropped.

So, I am trying to project an Apollo type method, very much made stronger, with variants of existing hardware and projected hardware of SpaceX.

Done.

Last edited by Void (2020-07-14 08:59:34)

tahanson43206 · 2020-07-14 10:30:22

For Void re #424

This is your topic, so your management preferences are the rule here.

However, I ** did ** follow the forum convention, of specifically addressing my reply to Calliban, and to a specific post.

For Calliban re #422
It is good to see you are still thinking about this interesting idea!

Perhaps your reply was not to either one of us, but to someone else entirely?

You can help us avoid confusion by simply indicating at the top of your message whether it is a reply, and if so to whom, and if so, to which specific post.

I have noticed that you are courteous to others when you intrude upon their topics, so perhaps you would prefer that I move to another topic?

You can indicate to others that you do not want intrusions on your topic. That would be easy to do and I'm sure SpaceNut will help you to enforce a request like that.

(th)

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