On Orbit fuel depot

GW Johnson · 2021-09-05 15:16:59

TH:

As to the ideas in posts 95 and 96, rotating about the long axis while docked tail-to-tail would solve a number of problems for refilling a mission Starship from a tanker Starship. That is entirely different from rotating about a lateral axis, but it is stable. It requires plumbing they have not yet installed or tested in their vehicle designs, but little else. That's a weight gain.

The anti-slosh baffles get heavier with this approach, though. You need them not just in the tank dome bottoms, but all over the cylindrical surfaces, too. And they have to be porous, so that all the propellant can actually drain through them.

GW

Last edited by GW Johnson (2021-09-05 15:18:12)

tahanson43206 · 2021-09-05 17:58:09

The NewMars Portal has received and saved three images that show a promising refueling configuration that combines ideas of Calliban and SpaceNut in impressive graphics. I'm planning to set them in imgur.com tomorrow, for all to see.

If the SpaceX team has not already thought of this, they are certainly likely to find the presentation interesting.

I admit that the solution looks remarkably cost effective.

There is even a scenario where Calliban's suggestion of using a momentum wheel would make sense ...

If the tanker that SpaceX sends up to collect fuel ahead of a manned launch is fitted with a momentum wheel, then no propellant needs to be expended after docking. The docked vessels can be spun up until transfer is complete and then spun down for undocking.

I must admit it is creative thinking like this that makes the NewMars forum such an interesting and rewarding environment.

Void, you still have the lead for creative thinking, but your example is clearly an inspiration to other members!

(th)

tahanson43206 · 2021-09-06 12:13:20

Here are three images from GW Johnson, in support of his concept for axial rotation of end-to-end Starships for refueling without bladders.

Text from the email for these images follows:

This one stores all kinds of propellants, and can maneuver to rendezvous with spent stages, and even add solid-propellant deorbit cartridges to them. It may require a crew to operate, who can be sent up in a taxi space capsule, for a moderately-short mission. It can transfer any type of propellant to any spacecraft, without (!!!) spinning the entire facility for artificial gravity, or without (!!!) utilizing ullage thrust, or without (!!!) presuming cryogenic bladders will really work. It can help with orbital debris elimination.
This concept PRESUMES propellant transfers from spent stages can be made WITHOUT ullage thrust, that is perhaps the weak point. This thing can be docked together on-orbit from modules and pieces sent up by pretty much any launch rocket. However, I'm guessing that the propulsion module can supply adequate ullage thrust for a cryo transfer from a spent stage that is not bladdered in any way. Everything else is covered. Cryo pressurization above the evaporation point is cryo vapor ONLY as the atmosphere. Any convenient non-reactive gas can be used for the storable bladder pressurant, but, DO NOT MIX THEM !!!! I suggest dry nitrogen.
Attached are 3 png files I drew in Windows "Paintbrush", one for the cryo tank modules that spin, one for the storable propellant modules that do not spin, and one for the facility all docked together, complete with a command module and a propulsion module. A whole bunch of spacecraft can dock with this thing simultaneously. Would have to start running real numbers to real requirements (there are none as yet !!!) to refine this concept any further. This concept addresses ALL the issues that I and others have raised.
If anyone has a better idea, I'd like to see it.

Above text is from email to NewMars Portal from GW Johnson.

(th)

tahanson43206 · 2021-09-06 12:17:32

The ideas depicted above are clearly new and not part of existing technical history.

For that reason, they deserve to be considered for patent, even if the rights to the invention are granted to the public for free.

The danger is that if the ideas are NOT patented, or otherwise protected from trolls, they can (and probably will) be appropriated by persons of low capability but ample funds.

Update at 14:35 local time

Draft 4 of the Lander Proposal were emailed to 5 members of the Project Team.

Please report if you did ** not ** receive your copy.

(th)

GW Johnson · 2021-09-07 11:19:40

The rotating tank idea applies to Spacex tankers, if they will keep the tail-to-tail docking idea. You spin the docked pair like a rifle bullet, to get the same cylindrical free-surface pattern I show inside the refill station rotating tanks.

I presume the vent connections are on the tank forward domes, you connect these to transfer the vapors. The tanks will need some sort of side-mounted fill connections, which will be "under" the liquid in the rotating scheme. Connect these with a line that has a pump in it, and power it up. Spin the cluster, then pump the propellants. When done, de-spin and disconnect.

This spin axis has the least inertia, so the impulse requirements for attitude thruster-based spin-up and spin-down are the lowest that they can be.

As for scavenging fuel out of spent stages with the facility I drew, I add another module at the center that has a work deck(s). You grab the stage with manipulator arms and put it on that work deck and tie it down. Which orientation depends upon where the connection is that you can use to extract the propellants. That connection needs to face toward aft for the facility. You also connect the vapor vent line, presumably to the forward dome.

Then you fire attitude thrusters accelerating the facility forward to settle the globules on top of that fill/drain connection fairly quickly, then fire up the electric propulsion to make your desired orbital change. The microacceleration of the electric propulsion will keep the propellant over the drain connection until you can pump it out, since the electric "burn" is always quite a long duration.

GW

tahanson43206 · 2021-09-07 13:41:58

For GW Johnson re #105

More details on axial rotation to achieve efficient refueling of cryogenic liquids in/on orbit

SearchTerm:orbit refueling technique for liquid cryogenic fuel
SearchTerm:refuel on orbit methods of for cryogenic liquids

If someone has ** lots ** of time and energy, and would be interested in helping, please investigate design patents along these lines.

It is remotely possible an inventor might have submitted a patent application for this idea, so if someone has ** even more ** time and energy, please investigate to see what might be on record.

If someone wants to do the above and is not currently a member of NewMars, and would ** like ** to be, Read Post #2 of Recruiting.

(th)

GW Johnson · 2021-09-09 15:14:46

I don't know anyone out at Spacex McGregor. And no one gets through that gate without a specific invite or an employee ID. So one cannot just drive out there and visit.

What I do have are a few connections on LinkedIn with some folks who work (or worked) out there. If I can figure out how, maybe I could send something to them, hoping it might get through. It would be a short piece of the refill facility document, just the part about the application to the Spacex tanker problem.

GW

tahanson43206 · 2021-09-09 18:03:27

For GW Johnson ....

Can you just call and ask for the Manager?

Chances are excellent that you will get through, and you can set up a personal visit.

You can offer the document(s) during that visit, and more importantly, invite feedback on what the Manager thinks is actually needed, as compared to what ** we ** might think is needed.

Update at 22:34 .... the 11 pages of the On Orbit Refill Facility are printed ... they'll have to go into their own binder.

Lander binder is filling up fast.

(th)

GW Johnson · 2021-09-12 15:18:12

Better yet, check your email. Why bother with underlings. I can get snail mail straight to Musk himself.

GW

tahanson43206 · 2021-09-12 16:59:32

OK! Will do ... next scheduled Portal Check is Monday AM local time.

(th)

GW Johnson · 2021-09-15 14:49:09

The on-orbit fuel depot notion I came up with was intended for low-inclination eastward low Earth orbit. Normally, ships would travel to the depot, either to replenish its supplies, or to refuel themselves from it. What I came up with is modular, there being a module for each different propellant material that is chosen to be offered. The spinning tank notion makes this possible with simple free-surface cryogens. Once spun-up on their turntables, you just leave them spinning.

This is necessarily a rather large station. It is difficult to move. But, if one CHOOSES to use it for scavenging supplies from spent stages, and then de-orbiting the same as space junk, then you MUST move the depot! Abandoned spent stages are simply NOT going to come to you. That is the purpose of adding a big electric propulsion module, and a whole slew of solar panels to power it. If you choose not to do this scavenging job, there is no need for propulsion other than occasional reboost, and no need for so many solar panels.

It does occur to me as an afterthought, that such a thing might also serve a useful purpose in orbit about the moon. There is talk of a refuel depot to be made part of NASA's Gateway boondoggle. Again, its size depends upon how many different propellants you intend to offer.

GW

SpaceNut · 2021-09-19 17:55:20

ABL Space selected for NASA Cryogenic Demonstration Mission will launch in 2023 and demonstrate in-space transfer of cryogenic liquid hydrogen (LH2), the most challenging but highest-performing propellant for lunar and deep space exploration.

https://ablspacesystems.com/

tahanson43206 · 2021-09-19 18:03:54

For SpaceNut re #112

Thanks for showing this timely update on the competition!

(th)

GW Johnson · 2021-09-26 15:58:03

I didn't see anything in those links that describes how they are solving the propellant ullage problem for those transfers. The tank in the inspection image is clearly a free-surface tank. The cylindrical forms about its periphery are not recognizable as anything I understand.

My guess would be they are spinning the tank so that the propellant is slung radially outward to cover those cylindrical objects. If true, those are the suction locations for the pump(s) that will transfer the propellant. But that is ONLY a guess.

GW

SpaceNut · 2021-10-08 19:58:45

kbd512 wrote:

GW,
GW Johnson wrote:
Meanwhile, does anyone have any experience at searching US patent files for prior art? The question at hand is whether the rotating-tank centrifugal-force idea for propellant ullage has already been invented. I can just barely cope with email, exrocketman, and these forum postings.
I'll keep searching, but this was rather interesting:
A Detailed Historical Review of Propellant Management Devices for Low Gravity Propellant Acquisition
It seems that Jason William Hartwig (guy who published the paper in the link above, has been a very busy boy- 837 page Bible of cryogenic fluid management in low gravity- give it time to load):
LIQUID ACQUISITION DEVICES FOR ADVANCED IN-SPACE CRYOGENIC PROPULSION SYSTEMS
Also, read the links from this page:
https://patents.google.com/scholar/10640897181136651319
As far as prior art is concerned (this is from ESA):
EP 0 476 720 A2 - Passive propellant management system
As far as the measurement apparatus to determine how much propellant is actually in the tank and how much to load, I think ULA has already determined how to do that:
Numerical Modeling of Pressurization of Cryogenic Propellant Tank for Integrated Vehicle Fluid System

GW Johnson · 2021-10-16 13:40:50

I've come up with a better idea for a depot than a bunch of spinning tanks mounted to the depot structure. It just "came to me" in a flash.

This idea still uses spinning-tank technology, but not on the depot. The craft to be refueled docks to a tank, detaches it from the depot and moves off some, then spins up with the tank docked to the craft to effect the transfer tank-to-spacecraft. Then it de-spins and returns the tank to the depot. You do this twice: once for fuel, then again for oxidizer.

Transfers to the depot from tanker craft work exactly the same way: detach the empty tank to be filled, move off and spin up docked tank-and-spacecraft, transfer, then despin and return the filled tank to the depot.

Spin-up/spin-down propellants are minimized, being limited to the inertia of spacecraft plus tank only. It's end-to-end docking with rifle-bullet spin, so the moment of inertia and total impulse required of the spin thrusters is minimized.

That's for the cryogenic materials only. The storables are in the same sort of bladdered tanks as the spacecraft that use them. You just dock with the depot and pump, from bladdered tank to bladdered tank.

The only design requirement imposed on craft transferring cryogenics is the need for propellant suction points out on the tank periphery, as well as on the aft domes.

I looked at the references Kbd512 so graciously provided. Spinning-tank technology is not among them. But ullage thrust is. Plus a variety of devices exploiting surface tension effects.

Excepting possibly kerosene, the bladdered storables are primarily for attitude/maneuvering thrusters. Those quantities are far lower, no matter which combination you desire. So there are hydrazine tanks for around half to 1 cubic meter each of hydrazine, MMH, UDMH, and Aerozine-50, plus tanks for about 2.5 to 5 cubic meters of NTO.

The storable kerosene, and the cryogenics LOX, LCH4, and LH2 are needed in far, far larger quantities, being main stage propellants. The kerosene transfers just like the other storables, except the tank is far larger, around 500 cubic meters or thereabouts. The LCH2 is near twice that, and the LH2 around 11 times that in volume, assuming large receiving craft, and roughly-equal frequency of demand. The shared LOX volume to support each of these is simply huge, that being the largest volume (and tank number) on the depot station.

Reboost and attitude control could be a combination of the storable propellants plus electric propulsion powered by some solar panels. There would be a power and propulsion module at one end of the depot station. The crew compartment would be at the other end. You want the NTO tanks near one end, as far from the 4 types of hydrazine tanks as possible, to avoid explosions-upon-contact, if there are leaks.

If you want this depot to also take on the role of scavenging spent stages for propellants before de-orbiting them, then you need to add considerable propulsive capability to the depot station. It would have to go rendezvous with the target spent stage. Otherwise, no need.

GW

Last edited by GW Johnson (2021-10-16 13:55:28)

GW Johnson · 2021-11-07 13:15:44

I'm getting an awful lot of readership at my "exrocketman" site for the darndest things. One that has really pulled in a lot of readers the last few days is the new posting "The Warm Brick Ramjet Device", dated 2 November 2021.

That makes me wonder if my site would be about as good a venue as any for the spinning-tank technology applied to an on-orbit propellant depot facility. The basic spinning-tank idea is already there. But the on-orbit facility that has the spinning-tank article as a reference, is not up there.

GW

tahanson43206 · 2021-11-08 09:07:35

For GW Johnson .... congratulations on the readership at Exrocketman!

I'd like to try to encourage you to stay on course for publication in Analog, and possibly other print publications.

Analog has a long history of publishing interesting and informative fact articles, often with a future orientation.

Your On Orbit Refueling article seems (to me at least) like a good fit.

If you have time, got to www.analogsf.com and take a look at the author guidelines. The publication accepts Microsoft docx, so you should be able to offer your work with only minor changes. They (apparently) prefer that authors avoid double spaces, so you can remove any you might have with a simple search and replace edit.

(th)

Calliban · 2021-11-08 09:30:33

A spinning depot does not need to reach high rates of rotation. You need enough gravity to transfer fluids, preferably without need for pumps. If the structure can be arranged such that propellant can drain into and out of tanks, without use of pumps, or driving liquids through pressurisation, that would provide the simplest design solution overall. Designing pumps that are lubricated and can withstand the thermal gradients and shock associated with pumping cryogenics and do so reliably, year after year, is a tough design requirement.

Spinning can be provided by an electric motor coupled to a flywheel. When the vessel is docked and coupled to propellant transfer lines, apply power to the motor. The flywheel rotates clockwise and the depot and attached vehicle rotate anticlockwise. Conservation of momentum. When fluid transfer is completed, apply brakes to the flywheel. The station and flywheel stop rotating, with respect to each other and any outside observer. With the exception of valves, the motor should be the only moving part involved, as fluid transfer is entirely gravity driven. Just couple the propellant lines, open the valves and apply spin. Power can be provided by a small solar panel, charging a battery. Would 0.01g be enough to overcome surface tension of the liquids involved?

Last edited by Calliban (2021-11-08 09:33:59)

tahanson43206 · 2021-11-08 11:00:59

For Calliban re #119 and forum in general...

It is good to have you back on scene, even if your time is limited!

Dr. Johnson and you are certainly thinking along similar lines. I liked the coincidences when they occur, and hope you get to see his work at some point.

The Laws of Physics are shared equally between the two of you (and everyone else) so it is the ** application ** of those laws that is interesting (for me at least) to compare and contrast.

I am trying to encourage Dr. Johnson to find a suitable print medium for his work, and I am inviting you to suggest the name of a publication that might be suitable. I have suggested Analog Science Fact and Fiction, because it has a long history of publishing forward looking fact based articles written to be understood by a global audience. However, other publications are under consideration. The problem (as I see it) with tightly engineering focused publications is that the visibility is low, although the impact might be significant if the article reaches the right person. The Analog audience is about as diverse as might be imagined, so visibility is much wider, but chances of reaching a decision maker are less.

Dr. Johnson has proposed a form factor for an entire business platform, most certainly including some of the physics you have written up in such a clear way.

If you happen to know (or know of) a person or company who would like to invest in the future Orbital Refueling market, please let GW Johnson know.

***
Dr. Johnson is currently considering only one orbit.

In contrast, I can foresee numerous (or at least several) orbital locations for a massive refueling station designed for the specific market.

The first (and obvious) location is coincidental with Texas/Florida.

Another would serve the European Union.

Another would serve the Russians (if they are interested)

Another would serve the Chinese (again, if they are interested... I expect they'll set up their own facility)

There are probably other market opportunities.

A massive station on the order of what Dr. Johnson has described are not going ANYWHERE after launch., They will need to maintain station with precision, so as to ** always ** be on the Corner of 4th and Main when any customer plans a flight.

We have seen some speculation that such a massive station might chase customers, but I consider that to be quite a whimsical notion.

Instead, a large support structure of small, powerful "tugs" will come into being to perform orbital plane changes as needed to corral wayward objects and bring them to the station for whatever economic value they may have.

(th)

GW Johnson · 2021-11-19 10:50:36

I have since revised the concept to a non-spinning tank docked to a non-spinning depot. The craft to be refilled docks to the other end of the tank, which is then undocked from the depot. Craft and tank move to a safe distance, then spin-up rifle-bullet style for the transfer, using pumps. Once done, they de-spin, and redock with the depot, then the craft undocks from the tank, leaving it at the depot.

Refilling the tanks from a visiting tanker works exactly the same way, except the transfer is to the tank by pump, not from the tank.

Storables do not need this; these are just bladdered tanks. You maintain pressure on the bladder to zero-out voids inside it, and just pump away.

I have also pretty much abandoned the notion of the depot going to the job, because as TH has pointed out, it is so big. The space tug going and getting the craft or stage to be refilled or scavenged for propellant makes more sense. The space tug notion also makes more sense for any repair station on orbit.

However, the propellant depot does require some propulsion for orbit adjustments and reboost, debris avoidance, and end-of-life de-orbit capability. Some of this will need to be chemical rocket for fast response, some could be electric where a slow response is allowable. To that end, I really like the idea of iodine-fueled ion thrusters, because the "propellant" is so easily stored and managed, and also inexpensive. See attached quote.

GW

quote:

From AIAA “Daily Launch” email newsletter for Thurs 11-19-2021:

Researchers Test Iodine-Fueled Ion Engines
CNET News (11/18) reports that French aerospace company ThrustMe released a study Wednesday detailing its successful experiment with a iodine-fueled ion engine used on Spacety’s Beihangkoshi-1 research satellite. This was the first time an iodine-fueled ion engine was tested in space.

Last edited by GW Johnson (2021-11-19 10:53:31)

SpaceNut · 2022-10-22 15:06:00

Void mentioned the use for this purpose On-Orbit Propellant Transfer

SpaceNut · 2024-03-01 19:36:08

bump refueling

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#101 2021-09-05 15:16:59

Re: On Orbit fuel depot

#102 2021-09-05 17:58:09

Re: On Orbit fuel depot

#103 2021-09-06 12:13:20

Re: On Orbit fuel depot

#104 2021-09-06 12:17:32

Re: On Orbit fuel depot

#105 2021-09-07 11:19:40

Re: On Orbit fuel depot

#106 2021-09-07 13:41:58

Re: On Orbit fuel depot

#107 2021-09-09 15:14:46

Re: On Orbit fuel depot

#108 2021-09-09 18:03:27

Re: On Orbit fuel depot

#109 2021-09-12 15:18:12

Re: On Orbit fuel depot

#110 2021-09-12 16:59:32

Re: On Orbit fuel depot

#111 2021-09-15 14:49:09

Re: On Orbit fuel depot

#112 2021-09-19 17:55:20

Re: On Orbit fuel depot

#113 2021-09-19 18:03:54

Re: On Orbit fuel depot

#114 2021-09-26 15:58:03

Re: On Orbit fuel depot

#115 2021-10-08 19:58:45

Re: On Orbit fuel depot

#116 2021-10-16 13:40:50

Re: On Orbit fuel depot

#117 2021-11-07 13:15:44

Re: On Orbit fuel depot

#118 2021-11-08 09:07:35

Re: On Orbit fuel depot

#119 2021-11-08 09:30:33

Re: On Orbit fuel depot

#120 2021-11-08 11:00:59

Re: On Orbit fuel depot

#121 2021-11-19 10:50:36

Re: On Orbit fuel depot

#122 2022-10-22 15:06:00

Re: On Orbit fuel depot

#123 2024-03-01 19:36:08

Re: On Orbit fuel depot

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