Phobos Refectory

Dave_Duca · 2017-05-05 12:47:39

As seen from The Mars Underground Documentary... the 3rd Stage glides along with the Hab Module and
is cabled for the Gravity Dance during the 6 month transit.

This Third Stage is a very big & expensive piece of hardware that
should be parked somewhere - so it can be used for the same task
on the return trip.

So that "Humans will be seen as arriving in an upright position when they return"

OK.. Phobos is a good place to park it.
Can't miss Phobos, right?

Phobos makes for an excellent location as a Transit Terminal, TeleComm Relay,
Temporary Shelter, Supply Storage & Transfer Point and, a spot to park your Dinghy !

RobS · 2017-05-05 16:02:28

Except it costs half a kilometer per second to get to Phobos and half a kilometer per second to get from Phobos to a decent orbit for trans-Earth injection.

SpaceNut · 2017-05-05 16:22:02

I am sure that we will get to the moons of mars someday but lets stay focuseed for getting to mars first as we may already have a moon detour along the way in the name of hardware and skill developement for mars useage.

Dave_Duca · 2017-05-06 16:56:00

Sorry...
I was still on-track to Mars Direct / Semi-Direct.

That 3rd Stage cost a tremendous amount of money
to aid the gravity-swing.
And, don't for get the cable that tied them together.

Reduce the litter and re-use the device for the return trip.
Since any object going from this planet costs $10M per pound.

Don't waste anything - work smarter, not harder, yeah?

Last edited by Dave_Duca (2017-05-12 08:16:57)

kbd512 · 2017-05-08 16:49:57

If there's a buried habitat on Phobos, it's a good camping spot if you can't make it to the surface. It'll block out nearly all of the radiation you'd otherwise receive. Unfortunately, there's no way to refuel on Phobos, so it won't do any good to go there just for giggles in a chemical rocket unless Phobos is your objective.

SpaceNut · 2017-05-08 20:05:32

A sortie mission to the moons of mars sure if we are unable to land on mars and are doing a trial loop for the mars cycle...but for a full duration mars mission that makes for a hugh ship....

Congress passes NASA funding bill, Mars mission date set A trip to Mars by 2033 is among the several long-term NASA goals included in a bill Congress just passed to fund the aerospace agency. The bill asks for a human mission “near or on the surface of Mars in the 2030s,” and specifically asks for a study to be conducted on the feasibility of a human spaceflight mission to be launched in 2033.

NASA Transition Authorization Act of 2017

https://www.nasa.gov/pdf/649377main_PL_111-267.pdf

Dave_Duca · 2017-05-12 08:23:32

Would be a rather bold effort to consolidate a Planetary Transport Commission.
A sort of "last word" on any manned mission departing earth to: anywhere.

Even bolder, if mentioned at the next World Space Week, instead of
a plethora of program proposals, and endless presentations of "how we are going to do this".

Does Anyone remember the Late: James S. Martin Jr.?

Anyone?

SpaceNut · 2018-01-14 10:54:24

Suggested alternative to not going to mars would be a no go for many members even with a BFR alternative or any other vehicles large enough to make it a real payday for mankind.

tahanson43206 · 2022-09-19 06:16:40

For Void .... your recent suggestion of making a hollow sphere for human habitation seems hinted at earlier in this topic.

I'm not sure what the word "refectory" means in the topic title.

Learn to pronounce re·fec·to·ry
/rəˈfekt(ə)rē/
noun
a room used for communal meals in an educational or religious institution.

If I understand Void's vision correctly, he would burrow into the center of Phobos, insert a balloon, inflate the balloon, and expand Phobos so it provides a thick radiation protection shield around the interior.

That seems (to me at least) like the sort of bold idea that fits nicely into the NewMars culture.

(th)

Void · 2022-09-19 07:25:09

That is one possible path, but it requires a lot of effort, before a "Proffit" is obtained. But I have wondered about "inflating" Phobos or Deimos.

I think that the layer of fine materials on the surfaces, also might be sintered into objects, including shells that might be protective. This method can use Oxygen and Carbon as construction mass because you don't remove them from the materials of the structure.

https://www.merriam-webster.com/dictionary/sinter
Quote:

sin·ter
[ˈsin(t)ər]
NOUN
geology
a hard siliceous or calcareous deposit precipitated from mineral springs.
solid material which has been sintered, especially a mixture of iron ore and other materials prepared for smelting:
"typical blast-furnace burdens are 80% sinter, 20% ore"
VERB
make (a powdered material) coalesce into a solid or porous mass by heating it (and usually also compressing it) without liquefaction:
"when the moisture is removed from the slurry the powder compact is sintered" · [more]
More definitions and word origin

Perhaps it would be possible to do a 3D print "Sinter".

But getting more advanced it might also be possible to reduce materials into metals and glasses, and to make a shell(s) from that.

In dealing with this information, we are more seeking questions than defining an end plan. The most useful thing is to figure out what to look for in these objects, and possible plans, so as to then test for "Ground Truth" about those questions.

If you built a maximum "Shell(s)" out of these materials, they would be huge relative to the size of the moons now.
So, that is a direction to go, but if you make a shell, it is likely because you want to protect something within, so you would use materials to make a lesser shell and things to be within it.

And another important thing is to plan over time. You have to have a practical initial deployment that can lead to subsequent metamorphosis of forms of the objects of para-Tara formation.

Done.

Last edited by Void (2022-09-19 07:34:40)

tahanson43206 · 2022-09-19 08:10:12

A Refectory is a communal dining hall (apparently)....

The creator of this topic is not available to ask for enlightenment.

It is up to us (the current generation of NewMars members) to try to develop whatever the idea was.

In Post #10 Void has added detail about what might be done with material comprising the moons of Mars.

However, the central question posed by Void, in his vision of inflating Phobos so that humans can take shelter from radiation inside the moon, is how a balloon might actually accomplish that feat of extraterrestrial engineering.

I've seen reports of bladders inflated by humans on Earth to lift heavy objects in a 1 G field.

At the center of Phobos, the gravity felt by a balloon will be zero, but the rocks and other material comprising the moon will be experiencing increasing amounts of gravity, until the maximum value is reached at the surface.

I presume that in addition to gravitational attraction of the individual chunks that make up Phobos, there may well be chemical bonds holding chunks together.

The balloon will need to "lift" against ** all ** those forces, so (I'm guessing) whatever material is chosen for the wall of the balloon will be remarkable.

It fact, it seems possible (to me at least) that the material does not currently exist.

The (hypothetical) balloon material must be strong enough to retain molecules of gas (perhaps CO2 since it is available locally) while under whatever pressure is required to lift against the combined forces trying to hold Phobos together, ** and ** it must be able to (somehow) stretch so as to expand, ** and ** (somehow) possess the ability to add material to itself so that it can continue expanding.

Phobos is not a perfect sphere. In fact, it is so irregular in shape that it's "snout" points at Mars throughout it's orbit.

The irregular shape of Phobos will have some influence on planning for expansion of a balloon at the center.

That would be the Center of Mass, of course.

(th)

GW Johnson · 2022-09-19 13:57:18

I spent a bit of time researching the moons of Mars on the internet. There are several conflicting pieces of information about them, and at least 3 competing theories about their formation. For most of my life, the conventional wisdom was captured asteroids, but I am glad to see a range of ideas now presented as candidates. What usually happens with our theories is that nature turns out to be a lot more complicated than our initial notions about it.

On the surface, spectra of Phobos and Deimos very strongly resemble those of C-type asteroids and meteors, those bodies being made up of what is called carbonaceous chondritic materials. Those materials are basically rocky minerals with appreciable bound carbon present in one form or another. That would seem to favor the captured asteroid hypothesis. However, from up closer, in the visible and infrared, the minerals appear to be very fine grained (unlike asteroids), and to be phyllosilicates very much like those all over the surface of Mars. That does not favor the captured asteroid hypothesis.

One other thing to note is that the inner moon Phobos is spiraling in toward Mars. It might be torn apart upon nearing the Roche limit, or it might actually crash into Mars. The time estimates for that are millions, not billions, of years. Deimos on the other hand, is spiraling outward toward eventual escape, much like our own moon here at Earth. That is a time scale of billions of years. Point is, these moon orbits are not nearly as stable over geologic time as they would first appear to be.

However, two other very important things weigh against that captured asteroid hypothesis. One is the apparent high porosity of these moons: something like 25-35% void space is the estimate, and that is higher than is thought normal for asteroids of this size and type. The other factor is that both moons have rather circular, and rather equatorial, orbits about Mars. Capture would have involved very elongated orbits not necessarily correlated equatorially. There is no apparent means by which captured asteroids might have transitioned to circular, equatorial orbits.

The other hypotheses include: (1) Two instances of a binary asteroid torn apart, with one piece captured as a moon. That helps with circularizing an orbit, but not necessarily with equatorializing it. (2) Some sort of dwarf planet collision with Mars that threw a bunch of Mars material up into a disk or rings, which formed perhaps multiple moons, some since lost. (3) Moons from a disk or rings of material left over from Mars’s formation, of which now only the two remain.

The porosity, surface composition, and surface grain size would suggest ruling out all the captured asteroid hypotheses. That leaves a dwarf planet collision and leftovers-from-formation as the two seemingly-likely hypotheses. Both of these involve (at least temporarily) disks or rings of material, which would tend to be equatorial with the spinning planet, and more-or-less circular orbits for materials not otherwise lost. Both would tend to favor having similar surface materials on the moons as are on Mars.

Now, some have suggested that the north polar lowlands on Mars, which seem to have once been an ocean basin, might actually be a giant impact scar. That would possibly tend to support the dwarf planet collision hypothesis. But, we really have no way to confirm it, yet.

About the only other thing I can think of by which to choose between the hypotheses would be water and other volatiles among the minerals in the disk or rings. If leftovers from formation, there would be little heating, leading to more volatiles to be assembled into the moons. With the dwarf planet collision, there would be enormous heating, and the materials that assembled into moons would be much drier of any volatiles. We do not know the truth of that, because nothing has ever gone there and sampled the interiors of these moons.

I do not know enough of the mechanics of how such materials assemble, in order to understand how these scenarios might affect the resulting porosity of the assembled small moons. We just already know that the porosity is abnormally large. We also have very little idea when such events might have occurred; there is nothing here that requires it to have been at the time of the solar system’s formation.
However, regardless of which assembly hypothesis is closer to the truth, I offer here the hypothesis that both moons are now dry, unconsolidated rubble piles, with little or no cohesion between the particles making them up.

It is the abnormally-high porosity that suggests this: that leads to many larger, more-direct paths between the particles, leading from the interior to the surface. That exposes the interior almost directly to the vacuum of space. Any volatiles that might have been present after assembly, are quite likely long gone from sublimation into vacuum. The longer ago you postulate the formation of these moons, the more likely my “dry rubble” hypothesis is to be true.

I admit I could be wrong, but this suggests to me that the “resources” to found there are almost entirely phyllosilicate minerals with some carbon-bearing mineral compounds. There would be no water ice, and no ices of any other volatiles. There will be nothing there from which to make drinking water, breathing oxygen, or rocket propellants. There is merely a regolith that you can pile up as a radiation shelter, or possibly sinter (at enormous cost in energy) into useful objects of no particular strength.

Now, here’s a question: if we go to Mars “in force” with a fairly large vessel capable of life support, artificial gravity, and radiation protection, then what do we need Phobos or Deimos for? Parking hardware for use later? I think not: it is far easier to rendezvous and dock in free fall than it is on a surface, even one with extremely weak gravity. In my opinion, parking hardware for later use is not a good reason to visit these moons. Trying to live upon them certainly is not, if my hypothesis is right.

I think the real reasons to visit these moons are for the science, not the settlement. The “settlement resources” are all down on Mars! We already know that from the results of many machines sent there. What we don’t know is precisely (1) What all is there? (2) Where exactly is it? And (3) Just how good is its quality? Real exploration answers those questions, and that takes both machines and people.

GW

Last edited by GW Johnson (2022-09-19 14:05:19)

Calliban · 2022-09-19 17:15:46

If these moons are indeed dry silicate rock, then their uses to spacecraft are limited to reaction mass. It is possible to use mass drivers as engines, by using magnetic fields to accelerate masses of inert material to high velocity. But such engines are big and cumbersome. Other uses could be radiation shielding for space stations or perhaps feedstock for space manufacturing.

tahanson43206 · 2022-09-19 17:19:47

For Calliban re Void's idea...

I brought this topic back into view to try to give void's idea a bit of exposure and perhaps some running room.

There seems to be some agreement that Phobos may be a rubble pile.

By any chance, can you (would you) take a look at the mechanics of inflating a balloon at the Center of Mass of Phobos, with the idea in mind of opening a cavity where humans might take shelter from radiation.

The mechanics of such a balloon may be outside the realm of Real Universe practicality, but I'm hoping the pure mathematics will yield to study.

(th)

Void · 2022-09-19 19:31:12

I don't think I am wrong to say that everyone is doing some guessing on the true nature of these objects. There is a large amount of uncertainty on how they formed and what is inside of them.

In the case of Phobos, it acts as if it does have a solid core inside of it that may be very fractured.

I will gather you some information from my other topic:
https://solarsystem.nasa.gov/moons/mars … /in-depth/
Quote:

Phobos and Deimos appear to be composed of C-type rock, similar to blackish carbonaceous chondrite asteroids. Observations by Mars Global Surveyor indicate that the surface of this small body has been pounded into powder by eons of meteoroid impacts, some of which started landslides that left dark trails marking the steep slopes of giant craters.

So, we are almost sure that these moons are at least in part a composite of the materials of the asteroid belt, perhaps similar to Vesta. https://www.nature.com/articles/nature1 … %20impacts.
Quote:

Abstract
Localized dark and bright materials, often with extremely different albedos, were recently found on Vesta’s surface1,2. The range of albedos is among the largest observed on Solar System rocky bodies. These dark materials, often associated with craters, appear in ejecta and crater walls, and their pyroxene absorption strengths are correlated with material brightness. It was tentatively suggested that the dark material on Vesta could be either exogenic, from carbon-rich, low-velocity impactors, or endogenic, from freshly exposed mafic material or impact melt, created or exposed by impacts. Here we report Vesta spectra and images and use them to derive and interpret the properties of the ‘pure’ dark and bright materials. We argue that the dark material is mainly from infall of hydrated carbonaceous material (like that found in a major class of meteorites and some comet surfaces3,4,5), whereas the bright material is the uncontaminated indigenous Vesta basaltic soil. Dark material from low-albedo impactors is diffused over time through the Vestan regolith by impact mixing, creating broader, diffuse darker regions and finally Vesta’s background surface material. This is consistent with howardite–eucrite–diogenite meteorites coming from Vesta.

What that means is that the outer dusty regolith of these moons can be an mix of impactors from afar, and the "Native" materials of the moons. Ejecta from these impacts may in part circle Mars until again impacting. Chances are this dust will also include some metal materials as well.

But the main lesson is "We do not know yet". We need some scientific probes, perhaps carried on a Starship without a heat shield that can go there by Ballistic Capture.

***I will eventually talk about "Balloons".

https://en.wikipedia.org/wiki/Phobos_(moon)
Quote:

30% ± 5%
According to 2 sources
Nevertheless, mapping by the Mars Express probe and subsequent volume calculations do suggest the presence of voids and indicate that it is not a solid chunk of rock but a porous body. The porosity of Phobos was calculated to be 30% ± 5%, or a quarter to a third being empty.
Phobos (moon) - Wikipedia
en.wikipedia.org
New values for the gravitational parameter (GM = 0.7127 ± 0.0021 × 10 −3 km 3 /s 2) and density of Phobos (1876 ± 20 kg/m 3) provide meaningful new constraints on the corresponding range of the body's porosity (30% ± 5%), provide a basis for improved interpretation of the internal structure.
Precise mass determinatio…
agupubs.onlinelibrary.wiley.com

So, we might wonder what is holding that pore space as void? (Not void of Hydrogen I expect).
I think it might be ice, but even more likely, it may be true that the gravitation within the center of the object is micro-gravity. If there are large chunks stacked against each other, by gravitation, what mass should the small particles be most attracted to? If it were Earth, we would not think that a hollow world could be there, as the mass is so huge it would squeeze the voids out (Something some people might enjoy).

What I am thinking is that the center of mass may not be in the center of the object, but in a location between the surface and center, but more towards the center.

If someone did build a thick shell world with a hollow inside, you could Thow a rock from the center of the void, and it would likely accumulate speed as it moved closer and closer to the inside of the shell.

So, I am not sure. Maybe. And no, I am not thinking aliens built it.

As for Carbon and Water? https://solarsystem.nasa.gov/moons/mars-moons/in-depth/
Quote:

Like Earth's Moon, Phobos and Deimos always present the same face to their planet. Both are lumpy, heavily-cratered and covered in dust and loose rocks. They are among the darker objects in the solar system. The moons appear to be made of carbon-rich rock mixed with ice and may be captured asteroids.

It appears reasonable that the outer coating of 100 meters / 330 feet is likely a mix, and may not represent the core objects inside. The Carbonaceous materials may not bake that much as they will plunge into a very puffy dust bed which is likely fairly cool.

But I am not certain of that. I also will not vouch for ice in the objects. I consider that it is a thing that can be tested for.

In the case that Hydrogen is not available in quantity, it would be available from Mars.

The idea of a unitary inflatable balloon appears to be not likely to work out as the center is likely full of massive chunks of rock.

We might consider a Starship as a Stainless Steel balloon of sorts, so if it can be inserted into the fine surface regolith, then that sort of fills your order, but not really.

If there are big rock chunks in the interior with significant void spaces, then an inflatable enclosure might be built in the spaces between them. Perhaps it may even be possible to push them apart to increase the void space.

It is my feeling that these moons may be in part captured asteroids, as they are fluid in side, per stacked shattered rocks, and this could have a tide. The Martian surface is binary. The Southern Hemisphere is higher than the Northern Hemisphere, and so that could act tidally to make the moons approximate an equatorial plane. But again that is a wild pitch. Maybe.

Deimos may be closer to what you want, as it may not have as much core materials as Phobos. But really, I am not sure building a giant inflatable balloon and inserting it inside of Deimos and inflating it is the best way.

Done

Last edited by Void (2022-09-19 20:23:28)

Calliban · 2024-03-24 17:51:30

Isaac Arthur's latest video on Phobos and Deimos.
https://m.youtube.com/watch?v=xGjeFPlLCVc

These two moons may be important way stations on the Earth-Mars transit route.

Void · 2024-03-24 18:52:26

I don't want to stink up your post, would like others to contribute. But I see you have some willingness to consider alternate ways to get a mission to Mars and back and then we hope eventually a continuous stream of passengers.

One thing I have been considering as an alternate method with Starship.
Suppose a Starship went to orbit, and then had Kilo power reactors attached to it and also electric rockets.
Then venting the remnant of the Oxygen and Methane, Starship tankers could fill its tanks with Argon, perhaps.
Then the ship could set off for a Martian Orbit.

I admit this then leaves us with a ship in Martian orbit with only an electrical power source. I was hoping to get a ship in orbit to be able to return to the Earth. The Oxygen could come from the Moons, but we are short the fuel, unless we can get it from Mars somehow.

So, it is not a finished thing.

But in reality, if it brought some of its needs with it, perhaps something could be done. It could bring its Methane perhaps, if that could be kept from boiling off. Or Methane could come from Mars.

But it is not a finished thing still.

I guess if the Methane tank could be set to not boil off, and the Oxygen tank were filled with Argon, perhaps it could go to one of the Martian Moons. and get Oxygen from that. Not an easy task really.

I guess I am wishing for the above, and then a Mini-Starship. I would like a Starship to land on Mars, more than one, to support a visit by humans or robots. Then the Mini, to bring the persons and samples back up to orbit to the return vessel.

But it is not finished still and not necessarily the best way.

But Isaac Arthurs video seemed to insinuate that the Martian Moons could be important to access to Mars.

I Don't establish what I have posted here as a firm work, just another way to try to think about things. I will make the claim that to go from Martian orbit to Earth will require less propellants than to launch from the surface of Mars to go back to Earth.

I hope I haven't wasted your time and post.

Done

Last edited by Void (2024-03-24 19:04:34)

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#1 2017-05-05 12:47:39

Phobos Refectory

#2 2017-05-05 16:02:28

Re: Phobos Refectory

#3 2017-05-05 16:22:02

Re: Phobos Refectory

#4 2017-05-06 16:56:00

Re: Phobos Refectory

#5 2017-05-08 16:49:57

Re: Phobos Refectory

#6 2017-05-08 20:05:32

Re: Phobos Refectory

#7 2017-05-12 08:23:32

Re: Phobos Refectory

#8 2018-01-14 10:54:24

Re: Phobos Refectory

#9 2022-09-19 06:16:40

Re: Phobos Refectory

#10 2022-09-19 07:25:09

Re: Phobos Refectory

#11 2022-09-19 08:10:12

Re: Phobos Refectory

#12 2022-09-19 13:57:18

Re: Phobos Refectory

#13 2022-09-19 17:15:46

Re: Phobos Refectory

#14 2022-09-19 17:19:47

Re: Phobos Refectory

#15 2022-09-19 19:31:12

Re: Phobos Refectory

#16 2024-03-24 17:51:30

Re: Phobos Refectory

#17 2024-03-24 18:52:26

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