New Mars Forums

Official discussion forum of The Mars Society and MarsNews.com

You are not logged in.

Announcement

Announcement: As a reader of NewMars forum, we have opportunities for you to assist with technical discussions in several initiatives underway. NewMars needs volunteers with appropriate education, skills, talent, motivation and generosity of spirit as a highly valued member. Write to newmarsmember * gmail.com to tell us about your ability's to help contribute to NewMars and become a registered member.

#1 2004-06-26 16:11:11

karov
Member
From: Bulgaria
Registered: 2004-06-03
Posts: 953

Re: Terraforming Io - usually ignored moon

Io is often excluded from the terraformation list of the Gallileans because of its location in lethal jovian radiation belt + its quite intensive vulcanism due to the huge tidal influences.

But both major obsicles could be tamed. Indeed they represent absolutely plentifull power sources ready for harnessing and harvesting.

The lethal in hours radiation is caused by the enormous mag-field of Jupiter which acts like a giant electromagnetic accelerator for captured particles in it. It occured Io to circle the gas giant namely in the middle of this belt. This enormous energy flow could be entirely captured by sort of giant circumjovian MHD-generator consistin of the loops of many dinamically supported 'mag-sails' and hanged as partial beanstalks electrodinamical tethers. This source only could provide the whole terraformed Gallileans world system with all necessary ecologically and industrially energy for billions of years "as the worls (Jupiter) turns" -- Puting the Sun`s contribite asside. Capturing the energy from this vast natural hyper-dinamo, will effectivelly block it from pearcing the Io environment with hard radiation. BTW, such way of illumination and heating of the satelites of free-roaming the interstellar space planets and brown dwarfs is already envisioned and proposed.

Such energy utilisation leaves us with just one problem -- the extremely intense vulcanism. It could be solved by sort of geological "weather control" or else, still non-existant, but the simpliest method would be to cover again the moon with water ocean (from bodies belonging to the Jovian system or 'abroad')- as it was billion of years ago --  which to be left to saturate with sulfur and other poisonous chemicals 'at will'. The ocean surface to be covered partially, and finaly completely, with floating colonies -- made of ice, water plants, concrete, whatever you want... The entirelly artificial solid surface sculpture in manner and design as you want. There are plenty of ways to extract the excess 'geo'termal energy which litters from beneath: Allow part of it to leak through the shell to warm the atmosphere/hydrosphere. Directly use the temperature difference to produce ellecticity, instal ocean-bottom hot vents HUGE biosphere, and extract and use the biomass...

I think the terraforming of Io is not only possible, but may be a condition sine qua non est other Gallileans terraformation. The terraformed Io will turn to be the natural richest land in the system. It shall not need the sun itself, too -- the hub (bussiness and political) of the only self-sufficient inhabited planetary-moon system within the solar realm.

Offline

#2 2004-06-27 12:42:46

MarsDog
Member
From: vancouver canada
Registered: 2004-03-24
Posts: 852

Re: Terraforming Io - usually ignored moon

Surface temperature of a lava lake on Io was measured to be 17C.
Molten sulfur below would be only a little above 100C.
Might be a good place land on and look for life.

Offline

#3 2004-06-27 13:00:55

~Eternal~
Member
Registered: 2003-09-25
Posts: 211

Re: Terraforming Io - usually ignored moon

Not so, think of all the radiation Io receives.


The MiniTruth passed its first act #001, comname: PATRIOT ACT on  October 26, 2001.

Offline

#4 2004-06-29 01:59:26

karov
Member
From: Bulgaria
Registered: 2004-06-03
Posts: 953

Re: Terraforming Io - usually ignored moon

Surface temperature of a lava lake on Io was measured to be 17C.
Molten sulfur below would be only a little above 100C.
Might be a good place land on and look for life.

Sounds plausible. The immense radiation, could be effectivelly blocked by the rocks several meters underground, or even the chemical products of thi intense bombardment to be utilized somehow by certain type of biota...
-
But if on (or in) Io there is no life - deep ocean bottom termal vent chemosynthetic organisms biosphere could thrive (after flooding of the surface with several kilometers of water column) imported from Earth (modified or not) or from Europa - if there is any. Should be considered, in this 'bio-ethical' line of thoughts the survivabilty of eventual local Io`s life after watering th surface -- it will represent strong artificially induced evolutionary factor. Forcing the possible life to change it`s environment is less harmfull way of simultaneously make habitable the planet WITHOUT extinction, but change of the native biota -- if exists. Creating artificial human-habitable surface on floating on the new ocean islands (coverin part or the whole planet) afterwards will isolate the two biospheres - native termal vent one and the photo-dependent earth-style... if we decide so.

Offline

#5 2015-08-15 17:40:23

undormant
Banned
Registered: 2012-03-25
Posts: 18

Re: Terraforming Io - usually ignored moon

I know Io is cold 180 minus C, but if we put an atmosphere around Io with an ocean would that be able to block the radiation? Would the volcanism provide enough heat to get the temperature at the surface above 0 C?

Offline

#6 2015-08-15 18:00:01

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 28,747

Re: Terraforming Io - usually ignored moon

I have fixed this topics shifting issue and will post thoughts later.....

Offline

#7 2015-08-15 19:53:45

Tom Kalbfus
Banned
Registered: 2006-08-16
Posts: 4,401

Re: Terraforming Io - usually ignored moon

We don't exactly have a topographic map of Io, or at least I couldn't find one, so I have no idea where the oceans would be. I suspect Io would have a global ocean with a large number of volcanic islands on it if terraformed. I suppose my tower idea would be especially relevant to Io, except in Io's case the towers would serve as a source of illumination. Assume 4/9ths of the surface would be covered with towers and the remaining 5/9ths of it would be the "canyons" between, The towers if inflatable structures could be 500 km high if desired. Maybe geothermal energy could be tapped to power the light sources.

Last edited by Tom Kalbfus (2015-08-15 19:56:56)

Offline

#8 2015-08-15 21:22:49

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 28,747

Re: Terraforming Io - usually ignored moon

Io Facts

•It orbits Jupiter at an average distance of 262,000 miles (422,000 km,) similar to the distance the Moon orbits Earth as well as in size. •It is the most volcanically active object in the solar system. •Volcanic plumes rise almost 190 miles (300 km) above the surface. •Io has an iron core just like Earth, meaning it could have its own magnetic field. •The moon's orbit cuts across Jupiter's powerful magnetic field producing 400,000 volts of electricity across its surface. •Jupiter's magnetic field strips off 1 ton of material from Io every second!

jupiter_moon_io.jpg

Lava Lake Loki on Jupiter's moon Io, up close only 124 miles in diameter

Offline

#9 2015-08-16 12:50:37

Tom Kalbfus
Banned
Registered: 2006-08-16
Posts: 4,401

Re: Terraforming Io - usually ignored moon

SpaceNut wrote:

Io Facts

•It orbits Jupiter at an average distance of 262,000 miles (422,000 km,) similar to the distance the Moon orbits Earth as well as in size. •It is the most volcanically active object in the solar system. •Volcanic plumes rise almost 190 miles (300 km) above the surface. •Io has an iron core just like Earth, meaning it could have its own magnetic field. •The moon's orbit cuts across Jupiter's powerful magnetic field producing 400,000 volts of electricity across its surface. •Jupiter's magnetic field strips off 1 ton of material from Io every second!

http://www.solarsystemquick.com/jupiter_moon_io.jpg

Lava Lake Loki on Jupiter's moon Io, up close only 124 miles in diameter

Well you have a source of energy, that could be useful, because unlike other outer solar system objects, Io is a ball of rock instead of a ball of Ice, that means you can have continents. The chief problem is how to convert this source of energy into something that would support a biosphere.

Offline

#10 2015-08-16 13:23:54

RobertDyck
Moderator
From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 7,781
Website

Re: Terraforming Io - usually ignored moon

I have suggested terraforming the largest moons of Jupiter. Put a ring of mirrors around the moon, extending from the shadow to a distance from the surface equal to the diameter of the moon. That would make the diameter of the light collecting area 3 times what it is now, or the area to collect light 9 times. A give the moon an atmosphere that is a mixture of oxygen with sulphur hexafluoride (SF6). That's a very heavy gas, so would stay on the moon and provide surface pressure in the weak gravity. That gas is also a super greenhouse gas, trapping in heat. Colourless, odourless, inert, but does give you a very low voice.

A science TV show demonstrating SF6: https://www.youtube.com/watch?v=u19QfJWI1oQ

A few catches. You would need something to actively stir the atmosphere, so oxygen doesn't just float to the top. So lots of wind. And Ganymede is believed to have so much ice that you wouldn't want to melt it all. An aquifer of liquid silicone with moon-wide currents to transport cold from the poles through deep soil to maintain a frozen mantle. If all the ice melted, Ganymede could get a 500 mile deep ocean.

But IO? Why IO? Earth's moon Luna has 1/6 of Earth's gravity. Ganymede is very large diameter, larger than Mercury and 77.7% that of Mars, but Ganymede has only 1/7 G. Callisto is almost as large as Mercury, 71.1% diameter of Mars, but 1/8 G. IO is smaller, about the size of Earths' moon, but higher surface gravity: 0.183 G (1/5.46 G). It's material is more dense. But the real problem with IO is sulphur volcanoes that blow material off the surface into space, and right out of the moon's orbit. Volcanic material orbits Jupiter. That could never hold an atmosphere. You're better off working with IO as it is. Treat it's properties as strengths. Volcanoes mean lots of geothermal energy, and sulphur can be used to make various industrial compounds.

Last edited by RobertDyck (2015-08-21 08:04:59)

Offline

#11 2015-08-17 10:43:08

Antius
Member
From: Cumbria, UK
Registered: 2007-05-22
Posts: 1,003

Re: Terraforming Io - usually ignored moon

Any plan to terraform Io faces some serious problems.
1.    Jupiter’s magnetic field rotates with the planet and would essentially sweep atmospheric ions off of the moon.
2.    Io is one of the driest bodies in the solar system.  Any terraforming effort would require importing water from the other Galileans.  Not such an insurmountable problem as it would be for Venus, but still an enormous project.
3.    Jupiter’s magnetosphere would tend to ionise any nascent atmosphere, which the magnetic field would then strip away.  It would therefore be difficult to get any atmosphere established.
4.    Surface radiation levels are so intense that it would be very difficult to work without substantial shielding being in place.

A dust shell around the moon might potentially absorb enough of Jupiter’s magnetosphere radiation to make the surface habitable to men in space suits, but it would need a column density of 2000kg/m2.  Not an easy thing to engineer.

Some sort of paraterraforming would be easiest, using a shell of some sort.  This might be more difficult with IO as the surface is not geologically stable.  If relatively stable regions can be found, then smaller enclosed ‘genesis caves’ might be a workable solution.  Maybe Mohole pits are an option, containing warm sulphur dioxide gas that can be replenished as it escapes from the top.  But the geological instability problem makes digging a deep hole more than a little hazardous.

Offline

#12 2015-08-17 16:22:41

Tom Kalbfus
Banned
Registered: 2006-08-16
Posts: 4,401

Re: Terraforming Io - usually ignored moon

Earth's Moon would experience the same problem with holding onto an atmosphere. Jupiter's magnetic field or not. Putting a roof over the atmosphere of Io would prevent Jupiter from stripping that atmosphere, those inflatable towers would help in setting up the roof, and you would need some sort of artificial illumination anyways.

Offline

#13 2015-08-21 01:04:23

undormant
Banned
Registered: 2012-03-25
Posts: 18

Re: Terraforming Io - usually ignored moon

Putting an atmosphere on a planet or moon is one thing, it's hard, I can't ignore that.

However, the math is in people and it shows an atmosphere would be stable around Mars and Pluto and Luna for Billions of years.

Why does it have to be a 'forever' atmosphere when millions or billions of years will do it?

I'm sick of the parroting on this subject really "it will loose its atmosphere"

Yes but in billions of years so it doesn't matter!

Offline

#14 2015-08-21 08:10:26

RobertDyck
Moderator
From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 7,781
Website

Re: Terraforming Io - usually ignored moon

It's not gravity. How do you keep an atmosphere when you have this?
io_volcano_big.gif

Offline

#15 2015-08-21 12:23:29

Void
Member
Registered: 2011-12-29
Posts: 6,975

Re: Terraforming Io - usually ignored moon

I see both points.  I am intruding again.

undormant:

Atmospheric loss is considered a loss, but where does it go?

Does it to the outer solar system and condense onto objects there?  Or leave the solar system?  Maybe some of each.  So comets from whatever location are potential sources of replenishment of atmosphere, but it requires energy and time, and a method to manipulate the objects.

Something has to cause the objects from the outer solar system to "Rain" down on the "Dry" objects in the inner solar system.

In the distant future, if humans or other inhabitants of a solar system, were to know what the secrets of Dark Matter, Dark Energy, and Gravity are, then perhaps they could work to "Water" the inner solar system with outer solar system objects.

But for now, I agree, that worrying beyond even 500 years is more than we should care about just now.  Mars will last more than 500 years if partially improved with it's local materials.  Venus may be habitable with partial alterations.

Shell worlds being in a gravity tow of a moon (To generate electrical power from an outer planet magnetic field) should be possible.  That's quite a lot.

RobertDyck:

https://en.wikipedia.org/wiki/Volcanology_of_Io
https://en.wikipedia.org/wiki/Sulfur_dioxide

SO2     Boiling Point:   −10 °C (14 °F; 263 K)

So that's somewhat lower than water.  If the moon were covered with water (And a ice layer) the water would be a bit less explosive than SO2

So if you were these way in the future "People" who could manipulate vast numbers of comets to "Water" IO, perhaps you could covert it to a Europa over time (But a Europa with much more energy).

To bleed off heat, perhaps you would target comets, to directly poke into hot spots, and make them explode and dissipate energy, causing an overall temporary loss of the moons heat overall.  The you would have to keep the bombardment up, until you had a water layer / ice layer / temporary atmosphere layer thick enough so that explosive volcano's could not eject too much material into space.  And the conversion of the moon to a liquid water cycle could take some time.

Really very far from our abilities, or what we might hope would become "our" abilities for thousands of years, I am guessing.

And I have ignored radiation.

I believe that the surface of IO warps about 6 feet? (Dim Memory) with the tides.  I would think the water/ice/atmosphere would warp also, and so, if you really did do this an choose to inhabit the moon, your best location would be on the top of the ice shell, but you would have to compensate for that, and you might also have earthquake driven tsunami that would certainly make living on the ice shell "Interesting".

As an alternative, perhaps you would opt for a very deep ocean, no ice shell, and a very thick atmosphere, and live in cities floating in the atmosphere.

I think this makes entertaining material for fiction books, but would much rather deal with Mars, Venus, Luna, Ceres, Calisto, and Titan as far more realistic.

Last edited by Void (2015-08-21 13:57:54)


Done.

Offline

#16 2015-08-24 05:18:54

Antius
Member
From: Cumbria, UK
Registered: 2007-05-22
Posts: 1,003

Re: Terraforming Io - usually ignored moon

Amalthea may be a better choice for terraforming, though I would suggest, still a bad one, as there are easier bodies to which it would certainly be applied first.  It is small enough to allow complete paraterraforming at a low atmospheric pressure without the need for gravity assisted shells.

Surround the moon with a carbon steel greenhouse and pressurise to ~1KPa (this is above the vapour pressure of water at melting point).  The glass in the greenhouse will trap solar heat, which along with the waste heat from nuclear power sources, will be sufficient to raise atmospheric temperature above freezing point.  The moon is mostly water ice, so will eventually melt to form a spherical ocean.  At a depth of 5km, the water pressure would be equivelent to 1bar.  At this depth, cities could be constructed.

The thin atmosphere and greenhouse would substantially attenuate Jupiter's radiation.  The top meter of ocean would therefore support algae that feed a larger ecosystem.  At Jupiter distances from the sun, this might just be sustainable using natural sunlight.

Offline

#17 2015-08-24 22:39:02

Void
Member
Registered: 2011-12-29
Posts: 6,975

Re: Terraforming Io - usually ignored moon

I clearly understand you are trying to find a way, even though the Jupiter system, especially the inner Jupiter system, is more or less some of the "Badlands" of the solar system.

I would make another alternative suggestion, that for Calisto itself, it may be possible to shape groves in the ice to be 1/2 concentrating mirrors, think of a long concave mirror, cut it in half, and from the bottom raise a wall almost strait up.  Make this of ice, put a reflective foil on the curved surface.  Then at the top of the wall, put a collector.  As Calisto has a fairly strait up axis, it should be possible to have the concentrated light impinge on the wall, and there to place a greenhouse.  Such groves, being as trenches which could encircle the moon, switching to a new one as you move up sufficiently from the equator to a higher latitude. 

Anyway, therefore using the little moons gravity for what it is worth, and concentrating it's light without have complex machines of metal with giant bearings.

Of with your method for small moons, deal with a small asteroid with water.  Some of the smaller ones have comet tails.

But you knew that easier targets are available.  I think that while it is fun to speculate on how to overcome a hard problem, it is likely that there worlds that we should forget about ever habituating, such as Jupiter itself.  The Oort cloud will most likely provide a massive alternative to some of these nasty situations long before  it becomes realistic to even try to deal with them.


Done.

Offline

#18 2015-08-28 07:56:17

Antius
Member
From: Cumbria, UK
Registered: 2007-05-22
Posts: 1,003

Re: Terraforming Io - usually ignored moon

Callisto would certainly be a much easier target for colonisation than Io or any other moon inward of Ganymede.  It has substantial gravity, is completely stable and still has enough sunlight for photosynthesis.  It is also outside of the Jovian radiation belts and the worst of its gravity well.  Undoubtedly one of the best pieces of real estate in the solar system.

Offline

#19 2015-08-28 12:57:30

Void
Member
Registered: 2011-12-29
Posts: 6,975

Re: Terraforming Io - usually ignored moon

A little modification there:
https://en.wikipedia.org/wiki/Colonizat … m#Callisto
Quote:

Callisto[edit]

Main article: Colonization of Callisto

Due to its distance from Jupiter's powerful radiation belt, Callisto is subject to only 0.01 rem a day.[6] When NASA carried out a study called HOPE (Revolutionary Concepts for Human Outer Planet Exploration) regarding the future exploration of the Solar System,[11] the target chosen was Callisto. It could be possible to build a surface base that would produce fuel for further exploration of the Solar System.

For me that is a good thing, because it might be possible to generate power from Callisto's orbital inertia vs Jupiters spinning magnetic field.

It would be a good base to start off with Jupiter anyway.  It is possible that the radiation belt will be modified some day, there have been speculations on how to do that.  As I recall, it might have come from a Russian.  The notion would be to have an orbital device that would eject the molecules from the radiation belt.  That's all I have though.

Having habituated Callisto, and having at least one "Shell" world in it's gravitational tow, I would think the inhabitants would always be searching for a method to move inward, perhaps next to Ganymede.


Done.

Offline

#20 2015-08-28 18:04:13

Void
Member
Registered: 2011-12-29
Posts: 6,975

Re: Terraforming Io - usually ignored moon

I would like your thoughts on translating your plan for Amalthea to the object in this article (Kepler belt object 48 km / 30 miles in diameter.

http://www.space.com/30415-new-horizons … arget.html

For my part, I would hope to use your shell method, a very tenuous atmosphere, and an ice shell over a melted ocean, as the end product.

Also, I might hope that a bubble of air could be enclosed at the center of the sea.  Inside that bubble of air could be artificial gravity devices.  I am both lazy and really not that interested in doing the math, if I can get you to.

What could the bubble size be?

How deep would the sea be?

Obviously this will require a power source such as fusion.

The method if accomplished should be relatively stable, except if your bubble should develop a air leak into the sea, with sea water leaking into the air bubble.   But that is a curious matter, would the center of gravity be within the sea?   Then it would be a spherical center of gravity.  I suppose it would depend how much solid matter was inside the air bubble.

It's hard to wrap my mind around it, which is sort of fun.

Last edited by Void (2015-08-28 18:06:08)


Done.

Offline

#21 2015-09-01 12:48:08

Antius
Member
From: Cumbria, UK
Registered: 2007-05-22
Posts: 1,003

Re: Terraforming Io - usually ignored moon

Void wrote:

I would like your thoughts on translating your plan for Amalthea to the object in this article (Kepler belt object 48 km / 30 miles in diameter.

http://www.space.com/30415-new-horizons … arget.html

For my part, I would hope to use your shell method, a very tenuous atmosphere, and an ice shell over a melted ocean, as the end product.

Also, I might hope that a bubble of air could be enclosed at the center of the sea.  Inside that bubble of air could be artificial gravity devices.  I am both lazy and really not that interested in doing the math, if I can get you to.

What could the bubble size be?

How deep would the sea be?

Obviously this will require a power source such as fusion.

The method if accomplished should be relatively stable, except if your bubble should develop a air leak into the sea, with sea water leaking into the air bubble.   But that is a curious matter, would the center of gravity be within the sea?   Then it would be a spherical center of gravity.  I suppose it would depend how much solid matter was inside the air bubble.

It's hard to wrap my mind around it, which is sort of fun.

Using newtons law of gravitation, I solved the case for an ice shell with inner diameter 10km and thickness 5km.  This is bounding for the case you described and is a reasonable minimum for a gravitational shell.  I chose it because cometary bodies with diameter of ~10km are very ubiquitous in the Kuiper belt and Oort cloud.  The internal pressure that precisely matches the self gravitation of the sphere is 22KPa.  If the shell is water instead of ice and a 1KPa pressure is used to prevent it from boiling, then the thickness of the required carbon steel pressure vessel with a SF of 4 is 5cm.  The mass of the vessel is 500million tonnes.  This is 0.12% the shell mass.

Under this scenario, the surface of the pressure vessel would serve as a radiator.  The ocean would remove waste heat from the inner pressure sphere by convection.  The marine life in the ocean may serve as a food supply for the inner habitats.  The bottom of the ocean could be covered with a floor of sediment and interconnected rock.  This would form a barrier to water ingress if your inner lining developed a leak.  A lighter outer pressure vessel could be built up from plates that are anchored to the inside of the shell.  Alternatively, a layer of ice some 250m thick could provide enough pressure to prevent the ocean from boiling with waste heat pumped to thin radiator tubes on the surface.

Last edited by Antius (2015-09-01 13:03:48)

Offline

#22 2015-09-01 17:32:00

Void
Member
Registered: 2011-12-29
Posts: 6,975

Re: Terraforming Io - usually ignored moon

Very good of you to do the work for me.

I see that ice is perhaps not the preferred method, since water is plentiful (If you can reach it) in the Oort Cloud/Kepler Belt.

The ice layer, is a sort of water conservation notion, but since they could indeed build a strong metal shell, why not?

As you have indicated, why not have a more pleasant "Radiator".  I might speculate that the surface of the sea could have as much "Land" as you choose to make. (Land just being a large variation on a boat/barge.

Nice.


Done.

Offline

#23 2015-09-03 00:09:10

Antius
Member
From: Cumbria, UK
Registered: 2007-05-22
Posts: 1,003

Re: Terraforming Io - usually ignored moon

Using the Steffan-Boltzmann law and assuming perfect emmissivity, each square metre of the outer shell will radiate 460 watts at a temperature of 300K.  If the electricity consumption of a future human is 10KW each (20 Times western Europe average) and this is generated at 50% efficiency, then the world could support 30million people.  If the world is surrounded by ring radiators, the habitability could be increased even further.  A volumetric habitat 10KM in diameter could house the entire population of USA.

I think the easiest way to build the outer shell would be a series of interlocking hexagonal iron blocks.  These could be locked together using iron long bolts.  If any section of the shell is damaged, it can then be capped off and quickly replaced.  Both the shell segments and bolts would be suitable for mass production.

Last edited by Antius (2015-09-03 00:20:39)

Offline

#24 2015-09-05 16:01:18

Tom Kalbfus
Banned
Registered: 2006-08-16
Posts: 4,401

Re: Terraforming Io - usually ignored moon

One problem with considering Io is people always insist on living on its surface instead of underground. Actually on a Moon like Io, living underground makes a lot of sense. The atmospheric pressure at sea level is 10 tons per square meter, that means that on Io you can have ten tons of rock and dirt sitting on top of ten tons of air pressure per square meter. A cubic meter of rock weighs about 3.3 tons on Earth, On Io it would weigh one fifth as much, so 5 blocks of stone 1 meter on a side would weigh 3.3 tons on Io, so 15 such blocks would weigh as much as the air pressure at sea level, you could bury a habit 15 meters below Io's surface, and by tapping geothermal energy in the right location, you could power artificial lighting for growing crops in caves.

Offline

Board footer

Powered by FluxBB