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#301 2019-05-30 07:00:18

Void
Member
Registered: 2011-12-29
Posts: 3,011

Re: Alternate BFR (Big Falcon Rocket)

So, using Starship, for passenger transport without Super Heavy.

https://www.teslarati.com/spacex-elon-m … aceliners/


Not Done.


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#302 2019-05-30 07:08:38

Void
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Registered: 2011-12-29
Posts: 3,011

Re: Alternate BFR (Big Falcon Rocket)

So, using Starship, for passenger transport without Super Heavy.

https://www.teslarati.com/spacex-elon-m … aceliners/

OK, this makes sense, I always felt that Super Heavy would be added risk and cost.

I can see also that they will expand the market for the service if they can drop the ticket price and prove safety.

And costal Asia and Europe along with North America, will be the bulk of passengers with enough money for the tickets as well I would suppose, for some time.

……

This does suggest that an "Evolutionary Pressure" will cause divergent types of Starships, that will share engine types, and overall shape, but will be specific to a task.  Of course we already expected Crew Ship, Propellant Ship, and Supply ship.  I had also read about a different type that would be used to clean up space junk.

……

It seems that SSTO for Starship suffers a blow in this article.  However perhaps that is specific to a passenger version with life support and luggage.

The only use I saw for SSTO would have been to wet lab a shell to orbit for use.  Such a shell would not have any re-entry provisions, or life support, ect.  Stripped down.  Maybe if the engines eventually reach maximum capability in a few years this might be ~possible?

But it is not that important.  If you are going to wet lab a starship, then perhaps you want to load it down with interior furnishings while on Earth, and then use Super Heavy to get it to orbit.

Done.

Last edited by Void (2019-05-30 20:59:00)


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#303 2019-06-02 20:48:51

Void
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Registered: 2011-12-29
Posts: 3,011

Re: Alternate BFR (Big Falcon Rocket)

Well, here I go again.  I may have a diamond in the rough, or I am polishing a turd.  We shall see. smile

I believe that I am not the only one who feels that a Starship is underutilized if used in the manner first proposed by SpaceX for going to Mars.  Don't get me wrong, what they plan is probably necessary in the beginning.  However, I intend to explore if a more efficient way can be found to get "Stuff" to Mars using a version of Starship.

This proposed method, requires that future Starships be multi-use, to Mars, and to make repeated excursions from the Martian surface to low Martian orbit, and back to the surface.  The engines will have so many trips in them, and so will the heat shield.  However, if I understand the asperations of Elon Musk/SpaceX, by discovering where the pica gets charred and then putting in active cooling to combat the charring, it may be possible that the heat shield can endure many such excursions.  I would want this thing to be fully automated, don't think I would want the burden of having humans in EVA suits trying to facilitate this notion in orbit.

I have seen drawings of a proposed Starship for launching satellites, and it is depicted as having an alligator jaws type "Front Trunk".  I would rather see payload doors like the space shuttle.  They could be in the upper half, which will have complications, or the lower half, which would also have implications on what is to be proposed.  If the doors are on the lower half, then of course the propellant tanks would have to be on the upper half, which could make it even more tippy than it is.  But not so bad when landing on Mars, as most of the propellant would have been burned off.

Some of you will turn off right now, because I am going to suggest that this method has to use "Ballistic Capture" to Mars.  But the method is to be un-crewed, and a bit of extra travel time won't matter that much.  In return you will get much larger options of when to launch.

What I intend is a barge of canisters with just one Starship to propel them.  These canisters will be cone shaped with a hexagonal base if the canisters are to fit inside of a Starship with a nose payload bay, and cylindrical if it is a Starship with a base payload bay.

I will suggest that the canisters will be of some type of stainless steel that is economical, and yet will serve as living quarters on the surface of Mars after their tasks of transferring from LEO to Mars is completed.  I want to use the crates after shipping the cargo.

Some of these canisters will be for propellant and some for hardware, and perhaps consumables.

It is tempting to suggest that the propellant canisters will have the common dome, and contain both Oxygen and Methane.  However then each is a potential bomb, and a chain of them could go off and destroy the whole barge.  Instead I favor separate cartridges for Oxygen and Methane.  To have a serial stack of each.  Then if there is a leak, the chances of explosion is reduced.

The reason I think that this is a good thing to do, is I suppose that if you had a very large propellant depot in orbit, you could fill the who string(s) of propellant prior to launch from LEO.  And I don't know how long a Raptor engine can burn, but I suppose if it is throttled back you could burn almost everything, except the reserves that the Starship itself needs to land on Mars, and also some to modify the Mars orbit when "Ballistic Capture" is achieved.

And this is why "Ballistic Capture" will need to be the method of insertion of the stack(s) to Mars orbit.  You could not possibly hope to do an aerocapture of the whole stack.  But if the launch method were used, it can be observed that the engines have been used to propel multiple payloads to Mars.  Not just one Starship and its interior payload.

In order for this to pay off though then you have to suppose that the propellant depot on Mars is fully running at a high rate of production, and that you can land the Starship and launch it back to orbit again, each time to retrieve a canister and bring it down to the surface.  In this case, I would possibly think that that Starship is never going back to Earth again.  I guess that depends on how well it can be kept going in this proposed situation, and if it is worth sending back to Earth for an overhaul.  I would rather not make it tuned to aerobrake back to Earth.  Rather I would want it to be specifically tuned to working in the Mars situations.

So, you might run it until it crashes.  Starting with the heavy canisters filled with provisions and equipment, and ending with the empty canisters that were for propellants.

As for the heat shield, it would not ever come screaming in from interplanetary space to do an aeroburn.  It would instead only descend into the atmosphere from a more merciful low Martian orbit.  This may help the heat shield to do multiple trips.

As for getting the canisters out of the Starship. I suggest a hydraulic scissors jack platform on wheels.  You would drive it up to the Starship, and then put out the stabilizing legs to keep it from tipping.  Then elevate it to the canister.  Then you would use a cable wench to skid it onto the platform.  Then you would bring it down.  Then you would bring it over to processing.  When you were ready to use the crate as pressurized housing, you would drive it over to that deployment.  You would then have a ramp that you could skid it off of the platform onto, and then onto the ground.  You would then perhaps use the platform on wheels with a bumper to nudge it into place, to join an assembly of these canisters/crates.  You would use cutting torches and welding as appropriate to purpose and desire.  Eventually you would cover it with regolith for various reasons.

In the case of cone canisters with hexagonal bottoms, then they should join nicely.  Not so easy for cylinders.

And that is about it for now.

Done.

Last edited by Void (2019-06-02 21:29:58)


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#304 2019-06-04 09:30:57

Void
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Registered: 2011-12-29
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Re: Alternate BFR (Big Falcon Rocket)

I have been thinking about the first two automated Starships to Mars.

As it is stated now, the primary option is to load them down with hardware, and land them and somehow get information on available resources.  I am going to speculate on an alternative, based on the apparent fact that there is already some thinking about delivering Hydrogen to Mars at first to get the first propellant(s).

I will attempt to present support for this notion.
https://arstechnica.com/science/2019/06 … fely-back/
Quote:

If conditions on Mars aren't what SpaceX expects in terms of resource availability, Wooster said SpaceX is considering bringing components of fuel to Mars for the return trip, likely in the form of either water or pure hydrogen. The company could also return a Starship with less than a full load of fuel. SpaceX has stated that it can return between 20 and 50 tons of payload from the surface of Mars to Earth with a fully fueled rocket, but it could do the return with less cargo and less fuel if required.

Don't get your feathers ruffled.  This is just pondering.  No money is yet spent, no rockets used, no people killed.

So, what if you modified a precursor Starship, to not have solar panels?  What if you enlarged the Oxygen tanks, and added a Hydrogen tank.
I know that boil off is a concern, but Blue Origin addresses that with it's proposed Blue Moon Lunar lander.  If you throw out the solar panels, then you simplify the flight plan, and void mass that can compensate for the added mass to bring more Oxygen, and Hydrogen also.  You have more liberty in pointing the ship during transit.  Of course I am thinking fuel cells to power the thing, one of the outputs of the fuel cells would be water, created during the operation of the fuel cells.  Perhaps that would be used for active cooling upon aerobraking to the Martian atmosphere.  Or it might be saved for humans later, or it might be dumped overboard in transit.

Presuming such a ship lands, then it is primed to process Martian atmosphere, and is set to endure a Martian global dust storm, for a reasonable time period, if one should occur.  It is not the most desirable way to go though.  But you would have choices chemically.  If you had Hydrogen in abundance, it might be possible to react it with CO2 from the atmosphere, and create Methane and Water.  And then of course if you have Methane, you will want Oxygen.  That is heavy.  To bring it along is cumbersome, but if you want to play, you have to pay.  It is not an ideal solution...

So, while I might want a ship with an enlarged Oxygen tank, and a standard Methane tank, and a Hydrogen tank, it would be better if solar power or even nuclear power could also be added.  Nuclear is going to be too hard I think.  It would also cause problems of safety for crew trying to approach the craft.  But I would not absolutely rule it out.  In the case of Nuclear, then the ship is contaminated, and you have to move the propellants from it, to the ship you would ride off of the surface of Mars.  And that might be done with some kind of a wheeled cart with tankage.  Don't' know relative practicality.


Solar might be OK.

I am thinking that if you could have a self deploying array of solar panels that could emerge somewhere relatively high up on the ship through a hatch that would open, and towards the sun, and hopefully at a slant, then you might do better than to simply rely on fuel cells and extra delivered Oxygen.  In that case if you reacted Hydrogen carried to Mars with CO2, then the output of Methane and water would give you the liberty to split the Hydrogen out of the water to be used again, and of course the Oxygen to be stored for propellant.

That kind of automation to deploy a solar array out of a perched Starship, though would be very hard I think, chances exist that deployment would go wrong.  But then again it might go right.

I anticipate that the ship would also have carried some test equipment which would be able to analyze the resources available.  If they still will have a cargo ring around the engines of the Starship, rovers might emerge from there to study the surface and subsurface.

……

A note is that Hydrogen boil off would be processed through fuel cells as energy, and feed to produce water, in transit.  Exactly how you get Methane when on Mars is a relatively open question.  If on board processing splits CO2 into CO and O2, then of course the CO can be reacted with CO to produce Methane, and I presume water.

The other thing that Blue Moon does with Hydrogen boil off is to cool the Oxygen tank so it does not boil off as much.  Similar could be done here to keep the Methane and Oxygen cool.

…..

Obviously there are trade offs.  However in this plan, you do not transport in flight solar panels so you lower mass, and you do not transport equipment such as mining equipment that will have to be extracted from the upper payload bay.  And the advantage here, if the whole process works, is that the device refines a load of propellants, and scouts the area, presumably with rovers.  And I would limit it to that.  I would really like the first ships landing to be the return flight ships, but then you would have to outfit them for a crew return, or you would have to expel some Hydrogen tanks, and perhaps have Methane/Oxygen fuel cells for power on the return trip.  I guess K.I.S.S. says thing twice about that.

So, keeping it simple stupid says that the original landers would just be tankage, fuel cells, rovers, and perhaps a big solar cell array.

And if it worked, you would have provisions on Mars before any humans landed.

Done.

Last edited by Void (2019-06-04 10:08:29)


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#305 2019-06-04 09:59:41

tahanson43206
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Registered: 2018-04-27
Posts: 1,072

Re: Alternate BFR (Big Falcon Rocket)

For Void

Void wrote:

I have been thinking about the first two automated Starships to Mars.
<snip>
Of course I am thinking fuel cells to power the thing, one of the outputs of the fuel cells would be water, created during the operation of the fuel cells.  Perhaps that would be used for active cooling upon aerobraking to the Martian atmosphere.  Or it might be saved for humans later, or it might be dumped overboard in transit.

Not Done.

You have many interesting ideas, and I enjoy reading your messages.  On this occasion, your observation quoted above caught my attention more than usual.

kbd512 has been speaking of the advantages of ammonia as an energy carrier in recent months.  An advantage of using ammonia as the transport form to deliver hydrogen to Mars is that the conditions for shipment are much less severe than are those for shipment of hydrogen in pure form.  A benefit is that Nitrogen for use by settlers arrives with the hydrogen.

Later in the post above, you reminded us of the suggestion published in Dr. Zubrin's first book, about transporting hydrogen to Mars to make methane.

Thank you for your creative thinking!

(th)

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#306 2019-06-04 10:13:18

Void
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Registered: 2011-12-29
Posts: 3,011

Re: Alternate BFR (Big Falcon Rocket)

Yes of course, that is borrowed from Dr. Zubrin.

I guess in my mind, this conversation is a "Measure Twice, Cut Once" process.  Examine options prior to committing to a plan.  I don't like the idea of those two first Starships, just sitting idle for two years waiting for humans to come an unload them and start mining water ice, and producing propellants.

While indeed cost might go up this way, safety might also go up for the beachhead effort to place humans and their machines on Mars.

Even if it turns out that the rovers discover that the resources desired for water mining are somehow not suitable, it may still be possible to have a human visit to the site, if some other useful resource is discovered.

In the case where you two spearheading Starships, are loaded with mining and processing hardware, and yet the site is discovered to not be suitable, then you have wasted effort in that case as well.  You would end up simply abandoning the Starship and all of its equipment.

OOPS!  Yes, consider Ammonia as an alternative. 

After all "Measure Twice, (Or many more times, then cut).  Good mention on your part smile

Done.

Last edited by Void (2019-06-04 10:19:33)


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#307 2019-06-04 17:20:41

SpaceNut
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Re: Alternate BFR (Big Falcon Rocket)

The beach head isn't the issue, its the mass when we do not have a bfr sytem or other SLS or some other heavy lift launcher to make use of but a falcon 9 heavy or cygnus to make use of as these will need to be built up in orbit to be able accomplish the task of transporting man to Mars. These greatly reduce what man can do in a limited payload application.
So we can lug what we need or figure out how to extract it from mars.

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#308 2019-06-07 14:38:07

Void
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Re: Alternate BFR (Big Falcon Rocket)

I have been thinking about the Starship proto-types MK-1 and MK-2.

It is not clear what will be done with them beyond their testing use.  If they will not have a heat shield, and will either be dumped into the pacific, or left in orbit, I have a suggestion of something useful, dealing with synthetic gravity.  Of course this is based in part on postings by GW.

I am guessing that they are not going to bother with life support on them, so that constrains, options, but not too much.  Enter Dragon 2.  That has life support.  And it may be operable in a similar time line as MK-1 and MK-2.

GW has calculated that if you joined two Starships end to end you could get .5 g if spun, and not, I presume discomfort passengers too much.

However it is quite possible that only one of the two will make it to orbit, and the trouble of joining them together I think is too advanced for now.  And as I have said, I think it likely that these proto-types will not have life support.  However they will have mass, and maybe some residual maneuvering abilities.

So, I am suggesting tying a Dragon 2 to one end with a cable and spinning the assembly.  I really think humble beginnings would be suitable.  So, less then Mars simulation and probably less then Lunar simulation at first.  Explosive bolts for the cable, so that the Dragon could disconnect that way if necessary.  Not necessarily human passengers.  The life support for Dragon 2 would be better lasting for a small mass of test animals, and so, needing less consumables the dwell time in this spin configuration could be longer.  And if things went well, work your way up to higher and higher g tests, and eventually if a trust situation is established, experiment on Humans.

I believe that there is a lower limit of up and down gravity simulation, that would be a good place to start I think.

And then perhaps something like ~1/12th g.  You never know we might get lucky and find out that just a little like that can keep a crew healthy for a trip to and/or from Mars.

Eventually, perhaps tests at 1/6 g (Lunar simulation), and ~.38 g, (Mars simulation).

Perhaps the prototypes would only be serviceable for this for the first one or more tests.  But I am sure that SpaceX will be able down the road to supply replacements to continue the tests.  That is if the Starship program continues.

Done.

Last edited by Void (2019-06-07 14:48:59)


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#309 2019-06-08 07:14:28

Void
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Registered: 2011-12-29
Posts: 3,011

Re: Alternate BFR (Big Falcon Rocket)

Following up on post #303.

I am thinking that if Starship did have a cargo compartment with a hatch, alligator door trunk on top, something with a space shuttle type doors, it may be possible to put a binary auxiliary propellant tank inside it.  In that case perhaps Starship may be able to go orbital without Super Heavy.  This does not preclude having a small cargo to deliver as well.  It would depend on the relative size of the cargo bay, and the size of the auxiliary propellant tank.  Then you have the option of leaving the auxiliary propellant tank in orbit for use as a propellant tank there, or to be wet lab material.

I like the idea of a shuttle type payload bay door system.  It worked for the shuttle.  However I would modify it.  I would have solar cells on the inside of the doors, and radiator on the outside of the doors, since it is going to be stainless steel anyway.

If the doors could be opened to display the solar panels within, then of course you then have an option of simplicity.  It of course then displays the cargo bay contents to the sun as well, which for some items could be a problem.  Having this method also brings to question if the Starship can keep from snapping in half when belly flopping into the atmosphere.  I guess there are always tradeoffs.

This idea is pretty good for the imagination I think though.

I did previously say I would like to keep Oxygen and Methane more separated for auxiliary tanks in orbit or on a trip to Mars.  Again trade offs.  But perhaps once purged these dual propellant tanks with the common dome, would be able to store either Oxygen or Methane in both sections.  Don't know about that, but maybe.

If the common dome tanks were then a part of an assembly resembling an American barge concept, that is the engines of the Starship pushing the cargo of auxiliary Oxygen and Methane tanks, and also consumables and equipment for Mars, then when empty at Mars, these auxiliary tanks with a common dome would be rather nice to wet lab to the Martian surface.

Of course I will repeat, the method of achieving Mars orbit from a solar orbit would be Ballistic Capture, where you may avoid aerobraking.

Done.

Last edited by Void (2019-06-08 07:22:36)


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#310 2019-06-08 09:12:00

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#311 2019-06-08 12:08:10

Void
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Posts: 3,011

Re: Alternate BFR (Big Falcon Rocket)

Thankyou Spacenut.  those will be useful tools.

I have had further thoughts on the spin notion, and so I will try to adapt it to a proposed flight ready system for going to Mars.

First using the established intention of method of flight that SpaceX proposes, which I believe involves a Hohmann Transfer, and a direct Aero-Burn and hover slam to the surface.

Then I think the potential emerges also to consider a Ballistic Capture alternative with a massive "Barge" assembly.

The math(s) will be variable on discovery of developed real systems, and the distribution of mass in the assembled system.

First the established and published notion.

……

As I have said, I would begin with a coupling of a Starship by tether/cable to a advanced Dragon with life support.  Animal studies.
At some point I would get rid of the thruster system which blew up in testing.  Not for crewed flights, but for launching animal tests, and also for use with humans.  No humans would ride that Dragon up so you can dispense with the risk and that mass.

Somewhere along the line in the animal tests, it might become prudent to shunt electrical power from the mother ship (The Starship), to the Dragon.  This would allow a more advanced life support, perhaps, allowing a prolonging of the animal experiments if desired.

Another upgrade along the line would be to replace the tether with an articulated arm.  Think Canada Arm.  And then the ability for the arm to swing the Dragon up to the Starship periodically to mate with it's airlock.  This would probably require a de-spin of the system first.

This would be so that you could change out sub-parts of the crew periodically, when you do go to humans.

Emergency contingencies needed involve some fail safe methods to recover from a fault.  Can the crew climb a ladder or be hoisted?  Actually, if you cannot de-spin the system, then you are probably beyond redemption, but still it is a thing to consider.  Should the dragon somehow become detached, then some contingency for that should be considered for recovery of it to the Starship.

Then we can consider radiation concerns for the Dragon and the Starship.  Solar flairs being a major concern per G.W., but also I think we want to limit damage to the crew from GCR, as we want top performance from them.  The Starship is to have it's own storm shelter, so that is covered I guess.  The option to stop the spin, and interpose the Starship between the sun and the Dragon is also an option.
And then there could be considered a "Bucket" in which the Dragon could be placed.  Maybe a "Bucket" with double walls, and a layer of water inside those double walls.

Every upgrade has a cost however.

Then we have to consider the difference between passengers and crew.  Crew, especially in the first missions have to be in the best condition possible.  Passengers will probably be exposed to interplanetary space just once in their lifetimes, and may not be expected to do much on Mars at first except recover their health to make them useful.

So, I presume that for the first crewed missions, perhaps 6 crew members, and in transit, 3 in the Dragon, and 3 in the Starship.  A rotation period for the two sub-parts of the crew.  If all goes well, no EVA suits needed, for personal exchanges.

A nominal proposal now, the 3 which will be the last to be in the dragon will spend their last episode of it at ~.38 g, to acclimate them to that gravity field.  They will be the "A" team when the Starship lands, and will do the first EVA's on the surface of Mars.  Prior to that the "B" team might have been toned up at up to 1 g, to make sure that they are fit of muscle and bone.  While the "A" team is doing the preliminary work outside, the "B" team will be there to back them up, and they will be getting acclimated to ~.38 g inside of the Starship.

But we have to prep the system, before we do an Aero-Burn into Mars.  The Dragon, and the arm either have to be brought into an unpressurized cargo hold prior to Aero-Burn, or they have to be disposed of and abandoned.

And so that is where I am with that at this time.


……

For Ballistic capture, I suppose if it is a big raft of various and sundry materials, after boosting to trajectory the whole assemble, then the Starship-Dragon (With arm) assembly can detach and do their thing at a suitable distance.  In this case they may have the luxury of hiding behind the detached raft of materials.

Presuming that a successful Ballistic Capture occurs, and the need for immediate aero-burn is not involved, then the Dragon and arm can be latched onto the raft/barge(s), the whole assembly then lowered to a near Mars orbit, and then the Starship is free to do some landings.  In this case I am going to presume that Starship can be filled with propellants in orbit, as I anticipate that the raft/Barge(s) assembly will have tanks of propellant to use for that purpose.

Ballistic Capture is a longer flight time, but with this system, I feel that muscle and bone tone may be held to acceptable values, and also Ballistic Capture allows far more launch windows to access Mars, I believe.


Math later.  There will be many situations, and animal testing comes first to even begin to know what the parameters for this should be.  We could do 100 calculations for 100 or more different supposed final structures arrived at.

Done smile

Last edited by Void (2019-06-08 14:13:27)


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#312 2019-06-08 14:19:25

Void
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Registered: 2011-12-29
Posts: 3,011

Re: Alternate BFR (Big Falcon Rocket)

I am thinking of an Earth "Up-Starship" and a Mars "Down-Starship, and the consideration of using a weaning process for the base/Settlement(s).

While the initial plan if it works can be considered like a Root-Canal.  Getting it done asap is preferable to say doing it over months of time.

But, it could be possible that a weaning process resembling the care of a young child, may be the way to go.  I at least think the two should be considered, and perhaps some selection of process be made then after such a consideration.

For using a weaning process, then I think Ballistic Capture would be the preferred method of delivery of bulk materials to Mars.

About an up and down Starship.

If a canister system is use to move cargo, then up and down is worth considering.

The Up Starship, would primarily move canisters of materials up to LEO.  The Down Starship would primarily move the canisters down to the Martian surface.  Of the two, if one were selected as the tug to move a raft of canisters to low Martian orbit, I would select the Down version.  Reasons being, you can't make Starships on Mars at this time, and the Down version would be specifically tuned to Mars.  It is possible that the Down version could periodically be returned to Earth for an overhaul, but I think that since Elon Musk as a aspirational idea hopes that Starships can be made for less cost than a Falcon 9 first stage, then although we want many reuses of the Down version once it gets to Mars, but hope that it makes more sense to usually not bother to send them back to Earth.  Just replace them.

The Up Starship, is already reasonably conceived by SpaceX apparently.  The alligator jaw front trunk version to deliver hardware to orbit would do, I think.  That version could be top heavy, as when you drain the propellant tanks you make the bottom lighter.  However if you are not bringing heavy cargo down to Earth, as would typically be the case, it could be just fine.

For Mars however, the typical action is to bring heavy things down to the surface of Mars.  For that reason, I would wish, if it is possible that the Cargo Bay would be as close down to the engines as is possible.  It would be expected that the tanks if they are in the upper portion will be almost empty on landing.  So, this would make it (LESS) tippy. (Corrected the word, "MORE" put "LESS" in its place).  But I don't know what the complications would be for having the main tanks remote from the engines.  As a compromise, the landing tanks could be near the engines, and below the cargo hold.  This could have negative implications for boil off of the landing tanks.  However, I think that if you have a raft/barge of containers in orbit, some which contain propellants, you could top off the landing tanks prior to a landing of a cargo.  It is even conceivable that at first the Down ships would be more greatly filled with propellant so as to be able to go back to orbit to get another load.  This would be in the beginning.  When the process is not yet weaned.

As time went on, you would set up Oxygen and Carbon Monoxide production on the surface of Mars.  The Oxygen, to refill the Down Starship.  Also Oxygen on the surface for life support.  So, the weaning process begins.  Note that you do not have to mine water yet except for life support of humans and other life put to the surface of Mars.  This would actually be a big step, as I believe that the Oxygen is the heavier item relative to the Methane.  For a while, you would still refill the Methane in orbit.

At this stage since you have to extract water insitu, you then begin mining on a small scale.  You figure out what the tricks are to it, and modify the next equipment to bring to Mars, according to those discoveries.

Beyond that when you have sufficient water, you may proceed with the processes already proposed to extract Hydrogen from water, and react it with Carbon Monoxide, or you might consider a fermentation process to get Methane.  It is possible that microbes presented with Carbon Monoxide and Water will process some of it into Methane.  So, you have options to test.

The down ship, if it has space shuttle type bay doors lower on the cylinder may need additional stiffing with thicker steel.  If so, that may be tolerable, as the Martian gravity is ~.38 g.

Also, it might be sensible to have a leg that comes out of the cargo bay as the doors begin to open, so that it can deal with the weight of the door, making the Starship tippy to that side.

More later maybe.

Done.

Last edited by Void (2019-06-09 10:49:11)


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#313 2019-06-08 14:55:22

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Re: Alternate BFR (Big Falcon Rocket)

The spin of water will be also an issue if the container for the water is only partially filled.

Magnus effect - Wikipedia
https://en.wikipedia.org/wiki/Magnus_effect

The Magnus effect is an observable phenomenon that is commonly associated with a spinning object moving through a fluid. The path of the spinning object is deflected in a manner that is not present when the object is not spinning. The deflection can be explained by the difference in pressure of the fluid on opposite sides of the spinning object.

Coriolis force - Wikipedia
https://en.wikipedia.org/wiki/Coreolis_effect

Contrary to popular misconception, water rotation in home bathrooms under normal circumstances is not related to the Coriolis effect or to the rotation of the Earth, and no consistent difference in rotation direction between toilet drainage in the Northern and Southern Hemispheres can be observed.

Centrifugal force - Wikipedia
https://en.wikipedia.org/wiki/Centrifugal_effect

In Newtonian mechanics, the centrifugal force is an inertial force (also called a "fictitious" or "pseudo" force) that appears to act on all objects when viewed in a rotating frame of reference.It is directed away from an axis passing through the coordinate system's origin and parallel to the axis of rotation. If the axis of rotation passes through the coordinate system's origin, the ...

Video of water spinning

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#314 2019-06-08 18:25:13

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Re: Alternate BFR (Big Falcon Rocket)

Well that is interesting.

I though about attaching to the engine compartment, but didn't think it was a good place.  So, near a presumed airlock on the leeward side, nearer the nose.  Instead of an arm, I suppose cable(s) could be used to draw it up to the airlock.  Perhaps a bit clumsy.  Something to consider.  In that case, presuming motorized, perhaps the system would not need to de-spin for linkup to the airlock.

If the water spinning is a problem, then I suppose baffles could be put in place, or use Paraffin wax instead.

I visualize the Starship tumbling end over end and swinging the Dragon on a tether, cable, or arm.

I think that method will not induce a sudden gyroscopic change of axis.

Done.

Last edited by Void (2019-06-08 18:25:50)


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#315 2019-06-08 18:49:48

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Re: Alternate BFR (Big Falcon Rocket)

FYI for Louis.  Been waiting for you to post it.

There is a new Cloud Licker 30 episode.  He reports that the plans for Starships wings, legs, and flaps are changing again.


Elsewhere;

Also, some rattle about how adding 2-4 engines to stand alone Starship for passenger travel would improve its capabilities.  I wonder what that would look like.

Perhaps I am posting to much?

Done.

Last edited by Void (2019-06-08 18:50:57)


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#316 2019-06-09 08:53:35

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Re: Alternate BFR (Big Falcon Rocket)

Finally posted by Louis but there is a reference for what the a video contains.

https://www.businessinsider.com/spacex- … ges-2019-6

Elon Musk is building SpaceX's Mars rockets in a tiny Texas hamlet. But getting them off the ground there may be harder than he imagined.

The changes of features will mean a delay to a finalized build of the BFR in any form.

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#317 2019-06-09 10:43:55

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Re: Alternate BFR (Big Falcon Rocket)

Nice....

In post #312, I begin to describe a "UP" Starship and a "Down" starship.

I am not surprised that SpaceX, has not gotten full blown onto the idea of containerization of cargo.  Their focus is on having Starships at all, and I think there are many like myself who are thankful to them for going this far, and of course I wish them total success.  They however, have purposely left the ideas of what to do, once you are on Mars, to the notion of a refueling depot, and how to make one, and then the idea of a base>Settlement>Sub-Civilization which they want other people to do work on.

However, if you do try to conceptualize that work, then it becomes sensible to think of containerization, and an "UP" and "DOWN" version of Starship.  Now is a good time to put feedback into the concept(s) of Starship, before actually moving bulk materials to Mars.

While I at first thought the containers should be of Stainless Steel, I am now thinking they should be of hard to get materials in the initial phase of Mars habitation.  Perhaps Aluminum. But of course you can do both Stainless Steel, Aluminum, and also other things.  In that case you would have choices, as to what to do with the containers.  Use them as structure, or scavenge the materials of the containers.  This is a nurturing process as a parent to a child.  Supplying nutrition to accelerate healthy growth, so as to raise a child to adulthood where it can get materials from Mars itself.

The philosophy behind an UP Starship and a DOWN Starship should be different.

An UP Starship will operate primarily from the surface of the Earth to LEO.  It can be as dainty as is allowed by physical realities.  It will also have full service on the ground and perhaps some servicing options in LEO.  Dainty also corresponds with "Lighter Weight", which is a desire if you have to cope with a 1 g force when not in LEO.  I do think that this type also might be retired to the Moon for a Moon base, if it becomes untrustworthy by repetitive use.

The philosophy for a DOWN Starship would be rugged, which means extra mass in many cases.  You want it to be a real Super Star Trouper.  And greater permissions should be allowed for this as the gravity field of Mars is ~.38 g.  To get it to orbit from the surface of Earth, you probably need the Super Heavy, and maybe you also even put a container with extra propellent into it's cargo bay.  That would be a heck of a rugged ship.  (I don't think it actually has to be that rugged).  Somewhat more rugged will likely do.  And it's structure may be different, because the options for servicing it, maintenance, will be different on the Martian surface, and in Low Martian Orbit.

Back to the containerization scheme.  A DOWN Starship, with the container option, might actually be able to host a container specifically for humans.  The interface of controls of the Starship could be an issue, but the Starship is supposed to be a robot anyway, that can launch, navigate and land.  So, really not such a problem.

Other loads could be housing to put on Mars, already set up for habitation in part perhaps over time Insitu materials from Mars, to enhance habitability of them.  Binary propellant tanks, Oxygen only propellant tanks, Methane only propellant tanks, CO only propellant tanks, water tanks, shells to carry hardware, (Those would later be repurposed).

As I see it we want to think about settling Mars in a manner resembling lighting a fire from flint.  You have to know how to nurture a spark to a useful and needed fire.  That requires "Telescoping levels of scale" in a sequence planed to achieve the desired result.

So UP would be gracile,  DOWN would be robust in nature(s).

Done.

Last edited by Void (2019-06-09 11:09:18)


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#318 2019-06-09 11:25:59

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Re: Alternate BFR (Big Falcon Rocket)

Building further on the previous post #317.

If possible, I visualize the payload bay, as being as low to the ground as other requirements will permit.  And for it to be partially enclosed by payload bay doors such as the Space Shuttle had.  I visualize solar cells on the inside of the payload doors, and these doors need to open much more than the Space Shuttle doors did.  Opening the doors may induce a tipping problem to a degree, so consideration of coping with that is needed.  Perhaps a special extendable leg that deploys as you just begin to open them.

As I see it then we have to balance the capability of unloading the container, if desired, against the potential to deal with energy and heat issues. 

As I see it, of course you want the Ship landed so that the sunlight would strike the solar cells.  A happy potential is that the doors being able to swing, will be able to follow the sun to some degree during the day.  And if desired, towards the night if in operable condition they could close as much at night as is desired to hold heat into the ship.  But the outsides of the doors, and the ship body itself can be to some degree radiators if desired.  Of course Mars being a colder place, that is a lesser problem that what we are used to in LEO.

The containers of course could be cylinders, but also could resemble gas cylinders, with rounded ends.  This would be an interesting way to unload onto a scissors lift, where a cradle in the bottom of the payload bay, would allow a controlled tipping of the cylinder onto the scissors lift.  Rounded would also be useful because as a wheel you could actually roll them.  However that is good and bad.  Of course you need to be prepared to prevent rolling and allow rolling as suits productivity.

A reflective foil could be placed on the ground on the sunward side, to increase the amount of solar energy the payload doors could collect.
There is a bit of conflict there with the unloading process, but it probably can be worked out.

As for use of the cylinders, they can be upright as deployed for a purpose on Mars, or they could be put down sideways.  And I am supposing the would be ganged together as is useful.

Done.

Last edited by Void (2019-06-09 11:41:17)


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#319 2019-06-09 16:26:59

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Re: Alternate BFR (Big Falcon Rocket)

I am pretty satisfied with the "UP" and "Down" versions.

For the Down version at Mars, a question is do you only re-tank it on the ground, and so have to put propellants for it both to fly to orbit and get cargo and also land?  That is an option.  Or do you at least at first also re-tank in orbit, from supplies sent by way of Ballistic Capture?

Obviously you burn less fuel if you tank up both on the ground and in orbit.  At first in fact it might be desired to tank fully in orbit, with enough to move back up to orbit.  Again a sort of weaning process over time.

But they might choose the hard core root canal method.  That is, send the hardware and do a death march to a hoped for first success at a full fledged propellant depot on the surface of Mars.  Of course that will largely be up to them.

I am also comfortable with the notion of thinking about swinging something like a dragon around for the crew to get synthetic gravity in flight.  I am presuming the first missions will stand similar to what SpaceX has said already, and do not anticipate that they would bring passengers at first.  In this method there would be more room in whatever cargo bays there are, for extra supplies, and redundancies of critical parts.

But I have now conceived of how to modify a "DOWN" Starship so that both crew and passengers can have artificial gravity.  I would think that that is preferred, once repeated missions have set up a base, as a sheltering device, and the track record of the Starships is more proven.

For a ballistic capture method without immediate aero-burn, you have a more lenient situation.



I am thinking of a whole canister, in a cargo bay, that you would host in the cargo bay while launching and landing.  However during interplanetary flight, it would come out on at least two tethers, perhaps with life support umbilical structures as well.  Sufficient length for the synthetic gravity you would desire at the locations in the canister where you want maximum.  Probably at it's "Bottom".  Like the pseudo-Dragon, it would fold out of the cargo bay to be in front of the nose of the ship.  And then you spin the thing during transit.

Not required, but it does seem that a space shuttle type cargo bay would make sense.  Again perhaps with solar panels on the insides of the doors.  But of course during re-entry to Mars, (Or Earth), somehow the solar panels have to be sheltered to a degree from heat.

The canister itself could have solar cells on it's sunward side as well.

Of course, you don't want an experience where a thruster sticks on and you get centrifuged to pieces.  That is a danger anyway.  You would not want a shuttle or a Starship to spin out of control that way.

While their could be a pressurized pilots nest near the nose of the ship itself, it is a robot anyway, so that's an option I guess.  Then prior to arriving to Mars, if you are doing an aero-burn, you must of course get the canister back into the cargo bay, and close it's doors.  Or you are all dead.

So, presuming you have a working Starship with it's needed propellants, then you land in a preferred way, it is hoped.

And then the question is, "Do you bring the whole canister back up?"  If it is sectioned, then I suppose you detach a small part for the crews return to Earth, if they are returning to Earth, but I suggest that the bulk of it stays on Mars as more habitation.  My feeling is that since it does not have engines or a heat shield, it is not sensible to expend the energy to bring it back to Earth.  Rather you mass produce them and use them once in flight, and then repurpose them on Mars, with a small section going back up for the crew's proposed return.  I know I said that the "Down" Starship should perhaps stay at Mars, but if you are going to return crew to Earth, then perhaps it would do to use some of them for that.  The ship might not be like a standard "DOWN" Starship anyway.  It might be yet another kind.

…..

In flight the organization of the habitation canister, could indeed have a crew section, but I would expect reasonable congress between it and the passenger section.

I would think that a gym could exist at the level where the most synthetic gravity was, and sleeping/private quarters at the "UPPER" end, where the Synthetic gravity was least.  For solar storms you would need hygiene and food-water in the storm shelter.  I presume that the storm shelter will double as the bedrooms/private quarters.

In between you could have various other spaces for other needs.

Done.

Last edited by Void (2019-06-09 16:56:50)


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#320 2019-06-09 18:10:29

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Re: Alternate BFR (Big Falcon Rocket)

Oh, just one more thing, (I hope).

It occurs to me that if you did have a Dragon, and it was up to it per heat shield, maneuvering, and parachutes, it could be considered to return the crew to Earth by that method and let the Starship land itself.  I don't know if that would be preferable or not.  It is something else to look at.  I am thinking that the Dragon would not separate until just before the landing event.  But you would also want to have the option to keep the crew on the Starship, in case the Dragon is damaged.  And it could work the other way.  If the Starship was damaged, the Dragon would be a lifeboat.

Done.


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#321 2019-06-09 19:03:43

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Re: Alternate BFR (Big Falcon Rocket)

The big thing for space x going from a falcon 9 to a BFR is not just fuels and engines but its the values that change based on them.
Lox is the common oxydizer for both uses, so mix ration and volume will be what will change for the lifting of payload to orbit.
The Raptor is to be twice the thrust value to the merlin 1D.

Is SpaceX’s Raptor engine the king of rocket engines?

https://en.wikipedia.org/wiki/Raptor_(r … ne_family)

https://en.wikipedia.org/wiki/Merlin_(r … #Merlin_1D

https://www.quora.com/What-is-the-diffe … or-engines

Trade off table
Fuel-graph-1024x576.jpg

Fuel ratio
Fuel-tank-sizes-1024x576.jpg

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#322 2019-06-09 20:12:51

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Re: Alternate BFR (Big Falcon Rocket)

Good info.  I am gradually grasping these things.  I have a bit to go though before comfortable assimilation to the point of full understanding.

Done.


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#323 2019-06-10 19:56:59

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Re: Alternate BFR (Big Falcon Rocket)

I do have some other use for bringing a dragon with on the crewed ships.

The plan that I understand it that two cargo missions go first, and then two crewed missions and two more cargo missions.

The dragon would be a refuge if you had a temporary malfunction of the life support in a Starship, and then hopefully it could be fixed.

If it could not be fixed, perhaps the other crewed ship could give assistance, the dragon might keep the crew alive in the afflicted ship, it would be hoped.  Can the cargo ships also lend assistance?  Maybe.

Of course I do not know if they will fly in a relative formation though. 

Done.


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#324 2019-06-17 18:52:30

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Re: Alternate BFR (Big Falcon Rocket)

Lets just call this entertainment:
https://www.bing.com/videos/search?q=Sc … &FORM=VIRE

And so, if they want to put a dragon in orbit, I will suggest putting a sunflower seed in orbit.  If for no other reason, to find out what is wrong with the idea.

I have such a seed in front of me, that I am looking at.  It could be a watermelon seed, or a Stone Spearhead, or a sunfish of North American fresh water.  The latter two do move through a fluid, the first two, may have an advantage to penetrate the ground (Not so sure about that).

The Falcon 9 has a sort of profile like that, but where the lower stage is tubular, the upper stage is also a modified tubular, with a sort of a point.  There are good reasons that they do not flatten in in a curved fashion, as they want the space to put satellite's in orbit and those typically are wanting to occupy a rounded space within the fairings I expect.

Obviously why I want the stone spearhead shape, is that you can perhaps cut through the troposphere with it a bit better, and you can belly flop / sky dive with its broad windward side.  The leeward side might better shelter things like doors, and landing legs, I suspect.
The landing leg, could be like a fin as the latest Starship presentation suggests, or might be foldable like a Falcon 9.  It might hide scrunched down on the leeward side until deployed.  And there might be more than one.

I am anticipating the use of pica on the windward side.  I don't want to wander too far from rational thinking.  Not more than I have already done.

I would make note that this object might have some glide capabilities, but I am only going to mention that and suppose that for the most part we would be sky diving.

Loony smile

The skydiver has legs and arms, which are used to hold a stance where the bottom on the leeward side takes the brunt of the heating.

I am going to recommend that the Spearhead be cut across, so that a minor portion is attached to the Super Heavy, and the major upper part is the Starship, with an engine bay below.

There could be fixed fins instead of the mobile deceleration and guidance fins, but maybe not fixed.  Just something to consider.

The engine bay has cargo space, where I think you could put something like Loon Flippers out of.  They would stick out more or less, to help guide the position of the whole ship.  In this case you would hope to allow a collective ability to move the tail up or down, and a paired ability to tilt it left and right according to how much sticks out.

I am aware that under hypersonic conditions, you would not want them to experience the wake of the air flowing off of the main body, so, perhaps, they would be very onto the inner skin of the lower portion of the engine bay.  It is conceivable that they could also somehow double as extra legs for the ship to land on, but that would complicate the tolerance to the heat of reentry.

As for the front balancing "Wings", I think I am already too far out of my element.  I would leave that to my betters.

…...

I have other weird ideas to consider adding to this.

While the bottom portion of the spearhead that is now attached to the Super Heavy, will drag vacuum below it on assent, I have wondered if it could have small engines that perhaps in a canted position would put exhaust behind the Spearhead.  This may fail the K.I.S.S. test, however.  But I want to explore it.

Positive possibilities may be that when the Super Heavy is done and detaches to return to Earth, this "Flanged" remnant of the bottom of the spearhead would act to assist the grid fins that I presume that they are going to use.  The rather small rocket motors on the flange, might be of use on re-entry and descent as well.  But they would also complicate things, so maybe K.I.S.S. says no.

One more thing for these motors to do during assent, I think just possibly, is to lubricate the Super Heavy's passage through the troposphere.  If all they are doing is filling the vacuum resulting from the angled flange during assent, they might distribute heated gas against the body of the Super Heavy, which being of stainless steel might tolerate the heat.  The heated gas should be lighter than the Troposphere gas, as it would be expanded.  The notion then is that you would end up with less molecules dragging on the surface of the Super Heavy.  But it would have to be done right.  You would not want to accelerate the gas flow to the extent that it flowed down the surface of the Super Heavy much faster than would the Troposphere gasses.  Just put the Supper Heavy into a linear bubble of heated and expanded, and therefore more tenuous by weight gas.  Vibration sometimes can be used as a lubricant as well.  If those heated molecules were vibrating more than the Troposphere gasses, there vibration might also serve to lubricate the passage.

I realize that I have much to learn, and won't be too put off by criticism that assists me in learning.

Done.

Last edited by Void (2019-06-17 19:27:47)


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#325 2019-06-18 17:00:25

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Re: Alternate BFR (Big Falcon Rocket)

Nasa and others make use of scaled models in wind tunnels to show how the entry into the atmosphere and launch will behave for the design. They also use simular test tunnels for heat sources to see how shielding will behave as well....

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