Alternate BFR (Big Falcon Rocket)

Oldfart1939 · 2018-03-06 01:55:28

Robert-
Unfortunately I've been away from my field for almost 10 years now, and the old "use it or lose it," w/r information has struck again. In addition, my information is centered around the state of 2008 knowledge level. One of the things I DO recall is the female of the species generally has a massive change in the hormonal balance around menopause, which seems to trigger bone decalcification. This hormonal change undoubtedly involves some of the peptide hormones of interest to us in this discussion. This Osteoporosis onset can be offset through use of Calcitonin as an injectable. It's manufactured synthetically by Armour Pharmaceuticals. Another polypeptide has been shown to decrease Osteoclast production, and it's called Amylin. Of which I know very little, other than it was a "hot item" around the time I retired. Study of Osteoporosis is undoubtedly important since it can serve as a model system to emulate decalcification through microgravity exposure. Only in the past year has NASA shown any interest in looking at the underlying biochemistry of decalcification and other microgravity induced diseases (or, more properly, conditions).

Your comments regarding bones containing nerves was accurate. But this is a new area for study of the transmitter-receptor system: what is the "gravity detector-transmitter release" system? This is undoubtedly hormonally controlled process, but constitutes a new cutting edge for some very cool research. Too bad my best sources of information on this type of studies have all passed on. I collaborated with Professor John M. Stewart at the University of Colorado Medical School for almost 40 years, and he was one of the pioneers in synthesis and biology of polypeptide hormones. He would have been a true fountainhead of information for all of us, but he sadly passed away about 5 years ago.

Void · 2018-03-06 20:21:47

Really good reading stuff! (O.F. and Robert)

......

I want to add something to BFR....A running ring like in skylab.

https://www.bing.com/videos/search?q=as … ORM=WRVORC

It could either be inside the ship or a torus attachment outside of the ship.

Either way there could be a learning curve to use it. Say BFR is tumbling and gives a .1 g force for sanitation gravity. This is actually double what I previously proposed. Then if you had a toroidal trackway, you could run and get even more force on your appendages. The legs, pelvis, and spine in particular.

This could be a little bazar as you would be running around the circumference of the ship while it was tumbling end over end.
Might tend to make you upchuck. I am not sure.

And another solution that other members have mentioned for Mars could be used. Weights added to the runners body to improve the bone shock, and I suppose perhaps increase the tearing of muscle. (Tiny rips that heal).

So, in my thinking if the running ring were on the interior, it would also serve as cabins for passengers during the night. Say the beds fold into the wall, and you use curtains in the night. A trial balloon. That way you clear the ring during the day, and use it to maintain physical health.

I think however this would require a major redesign of the interior of the ship, and I don't know how close you could get the running ring to the tail end of the ship.

So I then looked at an exterior ring, and attachment.

As you might have gathered, I do not prefer Hohmann transfers. I prefer ballistic capture, but of course the time penalties are against it, but the very much more free launch options are very attractive.

The fuel savings might be attainable if you do a hybrid travel involving some degree of Ion propulsion.
The fuel savings however are not in my opinion the major objective.

So, an external toroidal ring. Attached to the tail of BFR, with a port to go in and out of it, maybe two ports.

How much radiation protection you apply to it is open for discussion.

As I see it the toroidal ring will not move up and down from the surface of a planet, it would remain in orbit. Just how you get it there in the first place would be a problem as well. It could actually be heavily radiation protected. Actually it could be the ultimate radiation shelter, if you used lunar materials. But for that mass you would pay a fuel penalty.

For ballistic capture method, you can unhook this exercise/radiation shelter torus and land on the planet.

For Hohmann transfers, you would either unhook it and dispose of it or it would have an ion rocket that would place it in orbit around Mars or Earth.

When you launched back up to orbit you would collect it and use it again.

It will probably be an expensive investment that you want to re-use.

Having a exercise and radiation shelter torus will make ballistic capture more justifiable. The flight times will be longer, but the health of the crew/passengers may be sufficiently protected.

...............................................................................................................................................
Well, that changes everything!

Instead of tumbling the BFR, why not return to the notion of rolling it on it's long axis?

So then BFR would dock with a more or less classical space station and take that with it.

There is going to be a fuel penalty and time penalty if you go from Earth to Mars by ballistic capture hauling this massive device. However you get health benefits with this.

As I see it now, you take the torus with you and do ballistic capture. Land the settlers, come back up the crew goes back to Earth without the torus and does a Hohman transfer.

The torus stays at Mars to become part of orbital infrastructure perhaps to mine the moons, or you send it back to Earth robotically by ion rocket.

......

Again about the solar panels you are also delivering to Mars. You can deploy them between the BFR and the torus, to generate large amounts of power during the flight to Mars, and of course to assist propulsion by use that power to activate ion propulsion.

When you get near Mars, you pack them back away. The torus probably has it's own dedicated solar panels to fly back to Earth with.

Now I am done.

Last edited by Void (2018-03-06 21:06:33)

SpaceNut · 2018-03-06 21:09:01

Edit I see that you finished about the time I sent the post before, so I may have phased some of you thoughts in a simular manner.

If sub assembly while refueling in orbit is viable option while the crew prepares for the trip to mars or back then the torus ring sound like a good construction item to figure out how to design it for its use. Like you were thinking the ring needs to seperate from the BFR at either orbit and stay viable for reuse for the next use link up while in an unused state in orbit. That would mean that it needs station keeping thrusters, fuel, power source (possibly solar) attach/ built into its design. The BFR could fly into its center to lock onto it and back out to allow its release of it from the BFR.
That said appears that the ring needs to be built in orbit for use from parts sent up. That said the only issue I see is aligning the ring with its hatch such that it links up with the BFR hatch for use.

Void · 2018-03-06 21:35:54

Fair enough!

Yes I see this as a later stage method, when humans are pouring out of Earth to Mars.

Before that of course modifications are likely inevitable, such as perhaps external fuel tanks, but basically doing SpaceX's BFR.

As apparently the USA and many foreign powers and SpaceX and Jeff Bezos are looking at the Moon, we might as well consider how this device could in part be built from Moon materials.

I might mention also that:
1) The BFR is likely capable of returning to Earth with no crew.
2) If crewed, then the crew might indeed try the tumble method to generate helpful synthetic gravitation. They would want a gym at one end of the ship somewhere.

Last edited by Void (2018-03-06 21:40:59)

SpaceNut · 2018-03-07 20:59:06

An inflateable ring sounds like a good means to create the torus for man use as well if a ridgid unit is not constructed for the artificial gravity use for exercise.

Void · 2018-07-01 10:31:20

I am not going into competition with Kbd512's Space BFR Variants. Rather, I have strong respect for that but want to express some things, but don't want to interfere with his encouraged posting. So I will use this place, in an effort to be respectful.

I think that BFR/BFS is quite a nice yardstick to figure out a system relying entirely on combustion engines, a system that can get fingertips on Mars.

However like Kbd512, I don't see why you would want to do that for cargo deliveries to Mars. And I don't see why you would want to generate more fuel on the surface of Mars than what could get your BFR/BFS ships into a stable Martian orbit.

This is not my main point, but I do desire to review "Ballistic Capture". After all the article implicates Boeing in it's calculation for Mars.
https://www.scientificamerican.com/arti … the-cheap/
As it happens "Ballistic Capture" does seem to fit in well with electric space drives, which is my main interest at this time.

*Note: Interacting on the "NewMars" site is a combination of frustration and learning. Today, I stumbled on something good:
Notable: "Why use lunar propellant?" and "Oberth maneuver".
http://www.thespacereview.com/article/3464/1
But I don't want to clutter up with all that. Just reserving the potential to add the Oberth maneuver and perhaps Lunar Oxygen to the game of electric propulsion.

BFS-Tanker Fuel Costs???
https://www.nextbigfuture.com/2017/11/s … iness.html
Quote:

Ex-NASA administrator Mike Griffin commented at the 52nd AAS Annual Meeting in Houston, November 2005, that “at a conservatively low government price of $10,000/kg in LEO, 250 MT of fuel for two missions per year is worth $2.5 Billion, at government rates.” If one assumes that a 130 metric tonne launch vehicle could be flown twice a year for $2.5 billion, the price is about $10,000/kg.
Currently a Falcon 9 launch costs an average of $57 million, which works out to less than $2,500 per pound ($5500 per kg) to orbit.As of April 2016, SpaceX had indicated that a Falcon Heavy could lift 63800 kg to LEO for a cost of $90 million a launch – which works out to $1410 per kg.
The target cost for the Spacex BFR is $5-10 million per reusable 150 ton launch. This would be $33 to $67 per kg.
Spacex is targeting once a week launches and the new Falcon 9 block 5 could have 1-2 day relaunches.

So, what if the propellant you lifted was Carbon or Dry Ice?
What if you also lifted solar panels for that cost?
Loft Carbon, if you intend to use Lunar Oxygen, loft Dry Ice if you don't intend to use Lunar Oxygen.
Of course I am thinking of electric propulsion which could utilize vaporized CO2. The Dry Ice being about twice as heavy as water ice for size. The temperatures of Dry Ice perhaps within constraints of available temperatures in space flight.

Dry Ice of course would be available from Mars. The Winters and Nights should make it relatively energy friendly to manufacture.
Dry Ice from Mars being for a return trip of a electric cargo vessel, which most likely would not have much cargo, or would have no cargo, unless somehow Carbon or Dry Ice could be taken from Mars to an Earth/Moon location at a lower cost than from Earth/Moon.

So what kind of electric propulsions might work with CO2?

Well there is this from the Europeans, I am guessing that if it can handle air, it might do OK with CO2:
https://www.sciencealert.com/new-electr … uns-on-air
Obviously you can dispense with the air compression technique.

Within this article are mentioned two different types of electric propulsion. I am interested in the one where radio waves are used to create plasma.
https://www.space.com/40999-tiny-electr … lsion.html
Quote:

"The same way a microwave oven uses microwaves to excite water molecules in food, we use the same kind of electronic parts you might find in a cellphone or a wireless electric charging mat to produce radio waves that can energize a plasma," Halpern said. "Xenon is the propellant most often used for electric propulsion, but we're also looking at air or water."
Phase Four's thrusters direct the electrons in the plasma outward using magnetic fields, either from permanent magnets or from electromagnets. The ions in the plasma follow the electrons outward, giving the plasma an overall neutral electric charge.

They are looking at air or Water. I am hoping that they could get those to work and CO2 from Dry Ice as well.

……

It is worth noting that if you did also go to electric propulsion for people, you could use exhaled CO2 as propellant, and in fact waste materials could be combined with Oxygen to produce propellants.

But for now, I am only looking at the cargo aspect. Still if you had an electric propulsion method that would put cargo from LEO to L1 for the Oberth Maneuver in a way you are using electric CO2 propulsion for the crewed/passengered missions.

Done.

Last edited by Void (2018-07-01 11:21:53)

Void · 2018-07-01 11:51:53

Per the just previous post #156, I need to inquire/speculate on processing Lunar dust at L1 with Carbon and Solar heat.

The Carbon being expected to extract Oxygen from the dust to form CO2. Therefore both providing propellant for missions to Mars, and then materials reduced of Oxygen to be used either at L1 or LEO, or elsewhere.

Further processing may yield metals, glasses?, and slag. The slag could be made into mineral wool fibers, as a construction material.

I do like it. A solar concentrating mirror oven heating a mix of Lunar dust and Carbon from Earth (Or later Mars???), to produce propellant and building materials. And if you wish you may split the resulting CO2 into 2 CO and 1 O2??? Then reuse the CO to reduce more Lunar dust.

Some of the Carbon would eventually get locked up in the building materials, but so what?

The O2 for breathing I would presume.

If you really do get a greenhouse effect that damages the Earth that drastic measures are required, then you may take part of the Lunar materials and simulate a nuclear/asteroid winter to cool things down.

Done.

Last edited by Void (2018-07-01 11:53:10)

Void · 2018-09-03 13:34:38

This Video features Dr. Robert Zubrin.
https://www.youtube.com/watch?v=cJCenuebAa8

Not Done.

Void · 2018-09-03 13:45:44

This Video features Dr. Robert Zubrin.
https://www.youtube.com/watch?v=cJCenuebAa8

I am becoming more and more comfortable with Dr. Zubrin's ideas over time.

If I understand what he has said in the video, BFR/BFS's best usage will be in the Earth/Moon system up to as high an orbit as possible without departing the Earth/Moon gravity well. I feel agreement on this, although I am also glad that the ship will be made so that it could go to Mars, if a reason appears. His logic apparently is that you don't want to idle a BFS by sending it to Mars and back. If you keep it in the Earth/Moon sub-system, then you might use it 10 times as often in the same time period. That sounds conservative to me.

He seems to indicate that a best practice would be to send mass to Mars not using the BFR, except to get the Mass up to a very high Earth orbit. He seems to indicate that he thinks SpaceX will come around to that idea.

He seems to feel that very little mass should be brought back from Mars to Earth. I am guessing samples, and a few humans could come back.

So, apparently he has a notion of an "Alternate Method" of BFR/BFS.

…..

I personally think that in some cases, ion rockets should be used to complete the intercept of Mars, and that ballistic capture could be used for cargo at least.

……

Now I am going to go off the deep end a bit. I am thinking that a stripped down shells like BFS could be sent to Mars to provide pressurized space. In this case reuse for flight would not be the policy. Perhaps recycling engines and fuel tanks, and landing legs could be done.

Of course a means to get this BFS Shell to LEO is required, which would be some thruster assembly at the tail of it. I am thinking that could be extracted after reaching LEO, purged, loaded into a Cargo BFR, and brought down to Earth for re-use.

The shell would do one aeroburn, a relatively gentile one, since it would enter Martian orbit by ballistic capture. It probably would not carry humans at all, and it is debatable how loaded with cargo it would be.

While a tail end landing would be possible, then you have to fear it might topple, and then you might very well want to carefully topple it to be horizontal for a better habitat shell.

So, I am suggesting four assemblies composed of engines, a landing leg, and fuel tanks, etc. A horizontal landing. The engines and legs would not be exposed during the aeroburn, but would pop out appropriately.

I think the value of this would be you could afford to land away from the established base so as not to risk a high speed crash into the base/city, and then this assembly might be refueled and flown like a hover craft to it's final destination.

The Engine/Leg/Fuel Tank assemblies removed as desired. Then they would be returned to Earth if that is worthwhile. One interesting idea for that would be to fasten the four together, refuel them and then have them fly to Martian orbit. Then by some means they would be returned to the Earth/Moon sub-system.

As for the nature of the shells, I would hope they could be made more low cost than the shells for the real BFS's. Once they were hovered to their final destination, perhaps they would be connected to a bigger assembly, and then covered with dirt or bricks. Perhaps compressed soil blocks. This would both provide some radiation protection, and some counter pressure by gravity.

Obviously they could be used as crew space, but I also think perhaps "Artificial pink light greenhouses". Perhaps both. White lights turned on when desired.

While Insitu is preferred, for some time this would be a way to accelerate the building of a base/town. There will probably be endless other work that the humans would be involved with.

……

Such shells might also work nice at the bottom of a lake. But you would have to weigh then down.

That's enough.

Done.

Last edited by Void (2018-09-03 14:23:22)

elderflower · 2018-09-04 05:52:44

If you are going to leave big rockets on mars, you may as well fit airlocks and passages to the fuel tanks and use them as pressurised spaces, Void. The rocket working parts would provide a set of spares for fixing the ones that do return.

Oldfart1939 · 2018-09-04 09:26:40

Bottom line: nothing is as simple as it appears on paper. As the Russian generals said to one another about Stalin's operational plans: "It looked good on the maps, but he forgot about the ravines." As SpaceX moves forward, they too will begin discovering the "ravines" in the somewhat simplistic planning for BFR/BFS.

Void · 2018-09-04 11:10:02

I have taken note of what both of you have said. You are not wrong.

But now I will revise my previous, partially on the basis of your posts, and on the basis of Dr. Zubrin's indication that we want to move "Stuff" to Mars, much more than bring "Stuff" back.

I think I might hear rocket men grinding their teeth. Have patience. Of course this will be "Half Baked". But you have to half bake before you fully bake.

For now I would like the shelf the idea of four engines/legs/tanks to land horizontally. I will try to stick to the tail landing which BFS is designed for.

SpaceX has explicitly said that they want to provide the transport, others should provide the means to establish humans on Mars.

So, I will attempt, but I will use BFS itself in mutated form to try to achieve this. Elderflower you influenced me.

Some of the stuff we might want on Mars, are shelter, and hopping spaceships. Maybe even hopping spaceships that can on occasion hop to a low Mars orbit, and return to the surface. (Without crashing).

So, I suggest a "Stubby Falcon Rocket/Spaceship". That is the same base as the BFS, less engines, smaller tanks, and a much shorter cone. Much less topple prone, and tuned exactly as possible for the Martian environment. It being stubby would be a greater problem for wind resistance on Earth, but I presume ~1% less the problem on Mars.

To cut things short I would hope to put it on top of a BFR on Earth. Put at least one long cone on top of the stubby cone, and launch it to LEO. It most likely would not carry any significant cargo other than the long cone(s), so it would be light, and having less engine power and less propellant tankage might work out.

So, the idea is to launch a largely empty stubby ship with long cone(s) attached. As there would be a space between the stubby cone and the long cone(s), cargo from a cargo BFS could then be transported into that space while it was in LEO. A BFS Tug might then per Dr. Robert Zubrin's coaching lift to a high orbit. Perhaps a translunar orbit to get a boost from the Moon?

So then the Stubby Falcon Rocket with lone Cone(s) could use its relatively small thrust capability to launch to Mars. I prefer Ballistic Capture, but knock yourself out if you love Hohmann. Could electric propulsion be involved? Yes, but that then adds complexity. Sometimes K.I.S.S. is the thing to do.

So then you get to Mars, and do an aeroburn, and land. You have an unknown amount of cargo. I guess that will depend on how many "Shell Cones" you sent with it, and what it's propulsion capabilities are.

But now you have a problem if you landed safely. You have cones to unload off of the Stubby Falcon Rocket. How you do that will involve lifting methods and tipping methods, cables, hinges, motors, wheels I am guessing.
……

For the shells, if you get them horizontal, join two together at the "Bases", and have an airlock at each tapered end, per Elderflowers input.
As I see it building such shelters on Mars would be very labor intensive, people in EVA suits or complex telepresence machines. Better to build them at first on the surface of Earth and transport them to Mars. There will be plenty of other work to do.
……

For the "Stubby Falcon Rockets" I suppose they can do a n# of flights with humans and as they wear out, then they become robotic "Stuff" transporters. And then finally parts and scrap.

I presume until a Mars society becomes grown up, they would be best promoted if the Earth sent additional Stubby Falcon Spaceships until they were able to manufacture their own.

Done.

Last edited by Void (2018-09-04 11:34:18)

Oldfart1939 · 2018-09-04 13:39:06

Elderflower-

One of the basic things I've gleaned in 50 years of industrial chemical experience: don't take a log and try to make cornflakes from it. You make lumber and sawdust. The residual BFS tankage should be used for the designed purpose of storing propellants. The "plan" is to make liq CH4 and LOX with ISRU, so we have immediately solved the storage problem by using these tanks for their designed purposes. One of the freight versions could itself have the entire Sabatier system onboard, as well as a Moxie unit. Don't make things more complicated than they already are...

louis · 2018-09-04 16:49:01

I agree entirely! No way would you use propellant tanks for anything other than storing propellant after landing...and even then, health and safety might determine propellant storage took place at a distance from the landing site. The landed BFRs would be good for general storage I would imagine. You might also be able to offload some of their inflight life support systems to use in habs on the surface. Other than that, we should think of them as the premier tourist site on Mars in about 30 years' time.

Oldfart1939 wrote:

Elderflower-
One of the basic things I've gleaned in 50 years of industrial chemical experience: don't take a log and try to make cornflakes from it. You make lumber and sawdust. The residual BFS tankage should be used for the designed purpose of storing propellants. The "plan" is to make liq CH4 and LOX with ISRU, so we have immediately solved the storage problem by using these tanks for their designed purposes. One of the freight versions could itself have the entire Sabatier system onboard, as well as a Moxie unit. Don't make things more complicated than they already are...

louis · 2018-09-04 17:00:57

I'm much more optimistic than you on this Oldfart, because it seems to me a lot of this is v. simple...just v. expensive.

When I say "v simple" I mean for Space X, not me personally of course. Rocket guidance, rocket engines, propulsive landings, propellant tank design, rocket skin...Space X seem to have this all locked down. Of course there's only one way to know for sure - when the BFR flies and lands successfully. But there's no reason NOT to have confidence in Space X (especially after that stupendous Falcon 9H launch).

A military operation like a WW2 campaign across several hundred miles of front is an incredibly complex operation involving millions of people, millions of miles of supply lines shipping millions of different items to precise deadlines, transportation on surface, sea and in the sky...so on and so on. So let's not get carried away. What Space X is trying to do is very difficult but not impossibly complex. The really complex bit is knowing how to put a rocket together and Space X seem to know how to do that. I prefer to think back to Apollo - that seemed an incredibly challenging task. But in reality it was fairly simple once the Saturn V rocket concept was turned into a reality. Yes, a lot of innovation was required but once the rocket was in place, the rest was in truth relatively minor stuff.

For me the next 12 months is going to be crucial. If Space X can get a BFR into the hop testing phase by mid 2019, then I say it's mission go for 2022, because it's the rocket that's the really big thing in the mission. The rest may require innovation, but can be done because it's all a collection of "bite-size" problems.

Oldfart1939 wrote:

Bottom line: nothing is as simple as it appears on paper. As the Russian generals said to one another about Stalin's operational plans: "It looked good on the maps, but he forgot about the ravines." As SpaceX moves forward, they too will begin discovering the "ravines" in the somewhat simplistic planning for BFR/BFS.

Last edited by louis (2018-09-04 17:02:40)

Void · 2018-09-04 18:00:14

Elderflower I appreciate your innovation.

O.F. I understand that you want to apply firm wisdom from your experiences.

Louis, I do trust SpaceX to do fantastic things, and to also have failures, as they have had before. Now is not the time to form a new technological orthodoxy. We should not put on silly church hats and robes, and say "Thus it is and so it shall be!". Now is the time to innovate.

SpaceX will soon not be alone. Blue Origins, the Vulcan, others.

I do like the second BFR. After all it is the second one revised from the first plan.

I woke this thread up as I decided to explore Dr. Robert Zubrins philosophy. Apply it to a next modification of BFR.

The second BFR is cool and gutsy, and I hope they make some. I would like to be assured that if need be, a ship could sail from the surface of the Earth to the surface of Mars. However it does violate to a degree the idea that we want to mostly send stuff to Mars, and much less from Mars to Earth.

But it has more engines and propellant tank size than is needed, once you leave the Earth. As I have said I will hope that they make some of the "Version II" BFS's, and in my prior postings lately I left aside the travel of passengers. I am mostly concerned with producing greater efficiency in the process of moving "Stuff" from the Earth/Moon system, and also a better adaptation the Martian environment.

For heavy grunt work we already know that they will likely build the BFS-Tanker, BFS-Cargo, and BFS-Satellite launchers, probably in the "II" described structure. That's great. They can grunt stuff up from the surface of the Earth and the Moon. They can also quite frequently land on the Earth to be serviced in a shirt sleeve environment (Sort of).

As for a BFR-Passenger(II), well it is bulky, and apparently does not have means for artificial gravity or a really strong radiation protection advertised for it.

After you jump off of the surface of the Earth, do you really need all of those engines to get to Mars? And if your engine weight were reduced, would you need as big of a propellant tank? Fine, as I have said I hope they will build some "Jack of all trades passenger ships".

But since they are apparently going to build at least four different types of BFS already, why not build one tuned for Mars and not Earth?

The (II) version BFS's apparently can land with one of two sea level engines? At least that is what I understand.

One of the things I note is that the BFS's that I see depicted look topple prone. It is OK for places where landing pads are, or in the beginning you might take a chance with a robotic one. (And risk a lot of value).

I have seen that other members would like something smaller for scouting and for hopping about on Mars. So, I suggested the "BFS-Stubby".

Same sized base, much shorter cone. I don't actually know if you can pull off a aeroburn with something like that from interplanetary travel with a Hohmann transfer, so I have suggested a ballistic capture to Mars orbit, and a more gentle aeroburn from low Martian orbit.

So, probably much more robust than a Dragon. Rugged, relatively topple proof even without a landing pad.

……

Now I begin wishing. I note that I think that the BFS is designed to land on either of the smaller engines on Earth or Mars. They aren't specifically efficient for Vacuum, as I understand.

Still what I would like to see is a BFS-Stubby, with a temporary long cone (For streamlining passage through the Earths troposphere).
I would like it to have reduced engines in number and reduced propellant tankage. Of course it has to have enough grunting capability to reach LEO after being boosted by BFR. The Long Cone can serve a second purpose as housing for people on Mars (Or the Moon), so then it is not wasted. In fact if you do aerobrake a BFS-Stubby to from Low Martian Orbit, then it would present greater surface area during the aeroburn, and so earn more of it's keep. Further, it also could hold some cargo to balance out the machine during the first descent.

Thereafter (When the long cone and cargo were removed), I would hope that it would have enough engine power to be able to hop about on the surface of Mars with a few people and their life support and tools, to be able to visit diverse locations, and perhaps deliver assistance to other people in distress elsewhere.

Ideally it could even have enough grunting power to reach low Martian orbit and even aeroburn and land again. Would it ever return to Earth to land for servicing? Well maybe on occasion. I am more inclined to think it should first be rated for passengers and then strictly for cargo and then finally junked for parts a materials on Mars. (And replaced periodically with new ones).

To me this seems logical, as time and technological innovation will not stop with the last unveiling of BFR that Elon Musk did some months ago. We never want to stop trying to do better.

Done.

Last edited by Void (2018-09-04 18:37:41)

Void · 2018-09-06 12:08:53

So, I have worked on this, more properly it may be that it worked on me.

I request tolerance. I am toys in the attic at this point but I think they are rather good toys, or will be some day.

A list of words that label certain actions. Reuse, Repurpose, Recycle, refuse.

SpaceX, Blue Origins and others are working on Reuse. I will work on Repurpose, or multipurpose perhaps.

So, for this we want to be able to think inside out, upside down, and perhaps sideways.

Vertebrates are structured with bones inside, Crustaceans typically with bones on the outside. Insects seem more like Crustaceans.

Crustaceans tend to molt as they go through different stages of life. Humans only shed exterior skin, or body parts is there is significant trauma.

So, I have already proposed having multiple shells on a BFR, and shedding the outer ones for a good purpose. I came up with some awkward proposals to turn them into housing on Mars (Or the Moon).

……

Now I think I have arrived at some greater potentials.

Things we want: Housing on Mars, Synthetic Gravity in LEO, and perhaps in the Earth/Moon System, housing on Mars, shelter.

The BFR/BFS is apparently constructed to have a cargo bay, and a door to inject or remove cargo.

But what if like a Crustacean we shed an outer shell when a BFR/BFS reaches LEO? We would still want a shorter shell so that the BFS can aeroburn back down to Earth. Now where we shed the shell to? To a construction site in orbit. Maybe like the ISS.

What about Cargo? Well you will see that the shed shell is cargo, but if it is significantly larger than the shell that the BFS retains to aeroburn, then we were free to attach cargo palates to the interior of the larger shed shell. No bay door, just do what is appropriate to plans with what is attached to the interior of the shed shell.

Per G.W.Johnson, as I remember from one of his posts, if we were to join two BFS's tail to tail, and spin them then we could go up to .5 g of gravitation.

So, if we have two of these shed cargo shells, we might contemplate joining them at their wide ends (not the points).

We need a joiner however. How about inflatable habitats?
Maybe these people?
https://en.wikipedia.org/wiki/Bigelow_Aerospace

Think of the two shells being tire rims, and the Bigelow device as being the tire. Also remember that holdfasts were included on the interior of the two shells, in order to hold tight the "Cargo".

Think of the Bigelow device as a space station hub. Think of some of the cargo being high tensile cables, and remember you already included holdfast points on the interior and maybe in some way on the exterior of the two shells.

It won't hurt at all to investigate how a tire and rim hold air pressure with a tire beed.
https://en.wikipedia.org/wiki/Bigelow_Aerospace

And the cable network and holdfasts to further assure continued solid connection of the various devices. Two shells, and one or two Bigelow inflatable devices.

Being paranoid I would search for further methods to assure pressurization.

So we have chances of G.W. Johnsons tumbling synthetic gravity machine. What to do with it? Well how about a baton space station. How about a baton interplanetary spaceship (In Part). Maybe even a baton (Stop the spinning) lander for the Moon and Mars. Habitat, Habitat, home sweet home.

So with his baton made real, (I hope) then what? Well .5 g at the points. A gym there. Be careful not to drop stuff that could puncture the shells.

At .38 gee a floor that simulates Mars. Maybe a Moon simulation further towards the rim. So that is your space station. You can research space medicine for Lunar and Martian gravity fields there. Probably in LEO.

I would also like to go places and in inhale my or other peoples poo, sneezes, pee, and so on (Vomit, Vomit, Dirrhea, Ect.). So I guess maybe .5, .38, Lunar gravity may do for that on this machine.

Not so sure we need this to go to the Moon. But to Mars, maybe a treat.

Propulsion methods? Well maybe a BFS tug, Electric rocket, a Shark Fin Magnetic Propulsion???, whatever works for the situation.

Lets drop down to things that are most known. A BFS tug pushes your baton to High Earth Orbit, perhaps elliptical, maybe then the baton gets sling shot out of the Earth/Moon system per gravity boost from the Moon, maybe later from the Earth, if you can put up with the radiation and gravity problems.

Well then next is aim, and corrective propulsion, and when you hopefully get close to Mars, a method to achieve orbit, or aerocapture, or aeroburn, maybe even a one time landing.

Personally I would start small. Ballistic capture, no aeroburn, no landing. You then need a landing craft to get your people and stuff down to the surface.

Aerocaptures to orbit and aeroburns with landing. That's going to be tricky stuff. For the aerocaptures, something new, you likely need some wings to handle unbalanced loads, and maybe some thrusters.

To land the thing??? Well I would not recommend humans on board. I would tend to suggest prior depressurization of the object. Landing thrusters at the mid section primarily. Good luck.

Insanity Done. Time for a road trip!

Last edited by Void (2018-09-08 12:31:25)

Void · 2018-09-08 12:33:52

Quote from my previous post:

I would also like to go places and in inhale my or other peoples poo, sneezes, pee, and so on (Vomit, Vomit, Dirrhea, Ect.). So I guess maybe .5, .38, Lunar gravity may do for that on this machine.

OOPS! That's what thinking inside out, upside down, and sideways does. No I am not a infectious waste pervert. Quite the opposite, I am somewhat compulsive to avoid such things.

Corrected.

SpaceNut · 2018-09-08 14:03:00

Images of boy in a bubble....

Space x's key to the BFR will be in the recycling of the "BFS-Tanker, BFS-Cargo," stages to which while they have shown the capsule Dragon's (partially as the trunk section is expendable) for the Falcon 9 it will be a big leap for the complete section for the BFR system.
This will need some materials engineering to make it happen such that it can be recycled hopefully with out reworking/ refurbishment of the section. It will be something that his engineers will have in mond in order to keep costs per launch at its lowest.

Void · 2018-09-09 19:30:11

Yes, to standardize and make those routine, will make a good foundation for further innovations, and leaps forward.

I do expect other players and methods to show their value as well. And yes as this is "Alternative BFR", I will re-mention the things I previously mentioned. Per posts #166 and #167.

That is quite a few things, but really most importantly a (Proposed) maximum 1/2 g synthetic gravity machine which might be put to Orbit(s), using hoisted exterior shed cones and perhaps Bigelow inflatable modules.

I have now understood that it can be baton like Mr. Johnson has proposed, but one Bigelow hub might support quite a few cones, say three, four, five, or 6. And you could join Bigelow hubs at the rotation axis and form still yet another "Star(s)" of cone spikes. It might be rather robust, as each cone may be somewhat autonomous of life support methods. And these could be space stations or interplanetary spaceships.

And then we have Blue Origins, Vulcan, and so many other USA and other national potential space programs who will all likely adopt variations of "Best Practices". If we can live another 10-20 years, I think we could be amazed.

Done.

Last edited by Void (2018-09-09 19:38:06)

elderflower · 2018-09-11 05:23:48

For Dr Johnsons rotating baton we need only dock the refuelled BFS (people) to the refuelled BFS (cargo) or a full tanker if that's what we want to send and rotate the result end over end. We already have docking clamps for refuelling.

kbd512 · 2018-09-11 12:14:33

Elderflower,

Can those clamps withstand a shearing and/or bending load associated with 250t+ of vehicles spun up to .38g or beyond (because that's exactly what you'd have if fuel or cargo shifted during transit), or just clamps sufficient to keep the two vehicles docked while fuel is being transferred?

I'm not saying it isn't possible, but there's a huge difference in the loads imparted into the structure.

SpaceNut · 2018-09-11 17:37:50

So butt to butt coupling to allow fuel to be pump to the ship needing it. The pail spinning says that the fluid will flow to the outer most part away from the center of spin towards what would be the top of the ship. The pressurizing of the tank is at that location so we would need to remove the pressure for the fuel to return back to the exit port for the pump to operate.

kbd512 · 2018-09-11 18:11:09

I wonder if there's some sort of electrostatic method to apply additional surface tension to a liquid propellant to both measure remaining quantity and keep it where you want it in the tank or perhaps use an electrostatic mesh that can move about in the tank. Maybe there's a way to use a Graphene additive in conjunction with a weak electromagnetic coil wrapped around the tank to "seat" propellant in the "bottom" (no real up/down/left/right in space, obviously).

elderflower · 2018-09-12 02:19:49

I wasn't proposing to spin the two coupled ships for fuel transfer, although it would work provided that the transfer pump suction is located at the top of the supplying tank and the vapour balance line returns to the bottom of the supply tank from the bottom of the receiving tank. I don't think this would be Spacex' preferred method of propellant transfer, though.
I was proposing only that the rig be combined and spun up after both components had departed earth orbit. The refilling of tanks would already have taken place by then. On approach to destination (Mars I hope) the baton would be spun down and the two components would be decoupled ready for capture burns.
And, yes, KBD, the couplings would need to be designed more strongly than would be the case for just inertial fuel transfers in orbit under thruster control. And the tank and payload mountings would see a reversed load, compared to normal acceleration and gravitational loads, but I doubt that would exceed atmospheric entry inertial loads of same.

Last edited by elderflower (2018-09-12 02:31:37)

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