SpaceX Workshop on how to get humans to Mars and then create a colony of hundreds

Philip Metzger is at the inaugural @SpaceX Mars Workshop. It is about planning how to put humans on Mars, then how to have 100s living there.

136 thoughts on “SpaceX Workshop on how to get humans to Mars and then create a colony of hundreds”

  1. I would speculate that current medical tech means that we can deal with fast, aggressive acute plagues a lot better than we can currently deal with slow, insidious, subtle diseases that take years to even show symptoms. That is certainly what seems to be the big issue these days, if you look at death rates in the industrialised countries.

  2. I would speculate that current medical tech means that we can deal with fast aggressive acute plagues a lot better than we can currently deal with slow insidious subtle diseases that take years to even show symptoms.That is certainly what seems to be the big issue these days if you look at death rates in the industrialised countries.

  3. Actually you would send cargo and people in different relays then. Nice delta V efficient burns for the cargo and fast trips for the people.

  4. Actually you would send cargo and people in different relays then. Nice delta V efficient burns for the cargo and fast trips for the people.

  5. That wouldn’t be enough. You’d need to multiply Mars’ mass by ~10 times to get Earth-like gravity. Just a few asteroids’ worth of mass isn’t going to make any difference.

  6. That wouldn’t be enough. You’d need to multiply Mars’ mass by ~10 times to get Earth-like gravity. Just a few asteroids’ worth of mass isn’t going to make any difference.

  7. Development of what? A colony? A colony should be recycling as much of its water as it can, so the amount used is roughly constant, minus some minimal losses and leaks. Evaporated water can be condensed easily on the Moon. Liquid water can be collected. Dirty water is easy to evaporate, and the vapor condensed into clean water. Water taken up by plants is either eaten and secreted, or composted and evaporated (depending which part of the plant). So it isn’t lost either. I don’t know how the ISS compares, but assuming 10 tons of water per person, it’s 10 million tons initial supply for a 1 million person colony. It’ll take a while to even get started, and further to build up, meanwhile the technology can be improved to minimize losses. So let’s say we can get ~10% losses per year, that’s 1 million tons per year. 20 years later maybe it’ll drop to 5% loss or 0.5 a million tons per year. Another 50 years maybe it can drop to 1% per year, or 0.1 million. So 10 mil initial plus 20 years times 1 mil/year plus 50 years times 0.5 mil/year is 55 million tons for the first 70 years. Out of the Moon’s 600 plus million tons (if confirmed). By that time we should have the infrastructure to import from elsewhere, but the colony would be pretty well developed already. For industry you generally want to avoid processes that treat the water as a consumable, unless it generates enough value to justify that. For example, reduction of Lunar oxides would use the water catalytically. You get the water back at the end. Waste streams in other processes can be recycled as above. For developing the cislunar-and-beyond infrastructure – sure, we could continue developing it far further than what Lunar water alone would allow. But the Lunar water should give us a good start.

  8. Development of what? A colony? A colony should be recycling as much of its water as it can so the amount used is roughly constant minus some minimal losses and leaks. Evaporated water can be condensed easily on the Moon. Liquid water can be collected. Dirty water is easy to evaporate and the vapor condensed into clean water. Water taken up by plants is either eaten and secreted or composted and evaporated (depending which part of the plant). So it isn’t lost either.I don’t know how the ISS compares but assuming 10 tons of water per person it’s 10 million tons initial supply for a 1 million person colony. It’ll take a while to even get started and further to build up meanwhile the technology can be improved to minimize losses. So let’s say we can get ~10{22800fc54956079738b58e74e4dcd846757aa319aad70fcf90c97a58f3119a12} losses per year that’s 1 million tons per year. 20 years later maybe it’ll drop to 5{22800fc54956079738b58e74e4dcd846757aa319aad70fcf90c97a58f3119a12} loss or 0.5 a million tons per year. Another 50 years maybe it can drop to 1{22800fc54956079738b58e74e4dcd846757aa319aad70fcf90c97a58f3119a12} per year or 0.1 million.So 10 mil initial plus 20 years times 1 mil/year plus 50 years times 0.5 mil/year is 55 million tons for the first 70 years. Out of the Moon’s 600 plus million tons (if confirmed). By that time we should have the infrastructure to import from elsewhere but the colony would be pretty well developed already.For industry you generally want to avoid processes that treat the water as a consumable unless it generates enough value to justify that. For example reduction of Lunar oxides would use the water catalytically. You get the water back at the end. Waste streams in other processes can be recycled as above.For developing the cislunar-and-beyond infrastructure – sure we could continue developing it far further than what Lunar water alone would allow. But the Lunar water should give us a good start.

  9. If gravity is an issue one possability is to set up several solar powered boulder catapults or solar powered canons that fire boulders to bombard mars. All reloaded by solar powered boulder collector robots. Place them on mars moons and on the amor asteroids all of having a goal of sending material to mars. Over time that would increase its mass. If could find an amor asteroid with ice could fill up inflateables with liquid to send to mars. Some of the liquid could be used as fuel to get the craft to mars. Hopefully some of these ideas will help to terraform mars.

  10. If gravity is an issue one possability is to set up several solar powered boulder catapults or solar powered canons that fire boulders to bombard mars. All reloaded by solar powered boulder collector robots. Place them on mars moons and on the amor asteroids all of having a goal of sending material to mars. Over time that would increase its mass. If could find an amor asteroid with ice could fill up inflateables with liquid to send to mars. Some of the liquid could be used as fuel to get the craft to mars. Hopefully some of these ideas will help to terraform mars.

  11. To warm mars. First put reflective material on phobos that will create more heat and light on mars for easier terraforming.

  12. To warm mars. First put reflective material on phobos that will create more heat and light on mars for easier terraforming.

  13. Most illustrations of a Mars habitat dome ignore the realities of structural design and radiation protection. The inside pressure, assuming it is sea-level Earth pressure, generates 27 tons/square meter of net lift due to the lower outside pressure. You therefore need minimal structural mass when the weight of the dome equals the lifting force. Otherwise the dome needs to be anchored to a heavy foundation to counter the lifting force. 27 tons per square meter works out to 10 meters of solid rock, or quartz glass if you want transparency. Either will provide adequate radiation shielding. Since Mars’ solar flux is a lot lower than Earth’s, what will likely be done is pile rock over the top of the dome, but leave windows around the rim. The windows will let in extra light from outside reflectors, which will bring up the total light level to Earth-normal. Then you can fill up the dome with plants for agriculture or just to have it look nice. Tunnels are fine for workshops and utility functions, and as emergency shelters, but it would be nice to have some “outdoorsy” spaces too. If the dome weight equals the internal lifting force, there is in principle no limit to how big you can make them. You need some structure to keep it from drifting around and flexing, but basically it is floating on air and isn’t limited like domes on Earth, which have equal pressure inside and outside. In the Earth case, they have to support their own weight, which limits their size.

  14. Most illustrations of a Mars habitat dome ignore the realities of structural design and radiation protection. The inside pressure assuming it is sea-level Earth pressure generates 27 tons/square meter of net lift due to the lower outside pressure. You therefore need minimal structural mass when the weight of the dome equals the lifting force. Otherwise the dome needs to be anchored to a heavy foundation to counter the lifting force.27 tons per square meter works out to 10 meters of solid rock or quartz glass if you want transparency. Either will provide adequate radiation shielding. Since Mars’ solar flux is a lot lower than Earth’s what will likely be done is pile rock over the top of the dome but leave windows around the rim. The windows will let in extra light from outside reflectors which will bring up the total light level to Earth-normal. Then you can fill up the dome with plants for agriculture or just to have it look nice.Tunnels are fine for workshops and utility functions and as emergency shelters but it would be nice to have some outdoorsy”” spaces too.If the dome weight equals the internal lifting force”” there is in principle no limit to how big you can make them. You need some structure to keep it from drifting around and flexing but basically it is floating on air and isn’t limited like domes on Earth which have equal pressure inside and outside. In the Earth case they have to support their own weight”” which limits their size.”””

  15. > The problem is that the moon doesn’t have significant carbon deposits This is why you want to mine Near Earth Asteroids. The “Carbonaceous” type contains up to 20% carbon compounds and water. This asteroid type is fairly common – Both Ryugu and Bennu, the two being visited by probes this year, are that type. Assuming you set up a propellant depot in Lunar orbit, your BFS can tank up there, then land and have enough propellant to take off again.

  16. > The problem is that the moon doesn’t have significant carbon depositsThis is why you want to mine Near Earth Asteroids. The Carbonaceous”” type contains up to 20{22800fc54956079738b58e74e4dcd846757aa319aad70fcf90c97a58f3119a12} carbon compounds and water. This asteroid type is fairly common – Both Ryugu and Bennu”” the two being visited by probes this year are that type.Assuming you set up a propellant depot in Lunar orbit your BFS can tank up there”” then land and have enough propellant to take off again.”””

  17. There’s enough water on the Moon to *start* development. But in the long term you will have to import more from elsewhere.

  18. There’s enough water on the Moon to *start* development. But in the long term you will have to import more from elsewhere.

  19. > the asteroids are yet further away still. That’s not correct. The Main Belt is farther than Mars, but there are already 18,500 known “Near Earth Asteroids” which come closer than 1.3 AU to the Sun. That puts them closer than midway to Mars. > Of course on the down side the moon lacks lots of useful things like Carbon, Nitrogen, Hydrogen, etc. This is why you want to exploit the Near Earth Asteroids *and* the Moon. Each has resources the other is short on.

  20. > the asteroids are yet further away still. That’s not correct. The Main Belt is farther than Mars but there are already 18500 known Near Earth Asteroids”” which come closer than 1.3 AU to the Sun. That puts them closer than midway to Mars.> Of course on the down side the moon lacks lots of useful things like Carbon”” Nitrogen Hydrogen”” etc.This is why you want to exploit the Near Earth Asteroids *and* the Moon. Each has resources the other is short on.”””

  21. A lot depends on what human low-G tolerance actually is, and, seriously, we need to know BEFORE we start colonizing. If 1/3G is enough, fine, Mars is a great prospect. If you need more, ironically you’re better off on the Moon and the asteroids, because large scale habitable centrifuges are easier to build without an atmosphere getting in the way. But, one way or the other, we need to find out.

  22. A lot depends on what human low-G tolerance actually is and seriously we need to know BEFORE we start colonizing. If 1/3G is enough fine Mars is a great prospect. If you need more ironically you’re better off on the Moon and the asteroids because large scale habitable centrifuges are easier to build without an atmosphere getting in the way.But one way or the other we need to find out.

  23. I don’t think you’re biased. It seems obvious that, except for exploration and maintenance of essential surface equipment, both Martian and Lunar civilizations would be underground. At least until Martian terraforming had gotten far enough along that you could get by outside without a pressure suit. But by then they’d probably just be used to building underground. Probably the first thing you want to put in place for a Martian colony is a SPS. All that dust, you don’t want to do the solar power on the surface, that’s been proven. And some local thermal reactors to keep emergency systems going in the event something interrupts the beamed power.

  24. I don’t think you’re biased. It seems obvious that except for exploration and maintenance of essential surface equipment both Martian and Lunar civilizations would be underground. At least until Martian terraforming had gotten far enough along that you could get by outside without a pressure suit. But by then they’d probably just be used to building underground.Probably the first thing you want to put in place for a Martian colony is a SPS. All that dust you don’t want to do the solar power on the surface that’s been proven. And some local thermal reactors to keep emergency systems going in the event something interrupts the beamed power.

  25. I think we’ll find that you can live there but the lifespan will be less. Any future Martians will know this and be good with it. The same way people smoke knowing the dangers. In the long term, I think it could be the new Florida. Seniors whose mobility has been diminished will find it easier in the reduced gravity.

  26. I think we’ll find that you can live there but the lifespan will be less.Any future Martians will know this and be good with it. The same waypeople smoke knowing the dangers.In the long term I think it could be the new Florida. Seniors whose mobility has been diminished will findit easier in the reduced gravity.

  27. We don’t know if 1/3 G is enough to ensure long term stays are healthy, nor if humans can have kids in that gravity well with an ethical long term outlook. And I’m not talking about survival of the newborns (which is most likely possible), but quality of life. If they are confined on Mars forever, it begets the question if we should do it in the first place. And if people can’t be born there, Mars doesn’t have a future. Nevertheless, I believe we will know one way or another. As soon as humans arrive there, some of them will let nature follow its course and then we will start getting the answer. That will be the big news scandal shortly after we arrive: the first baby born on Mars!

  28. We don’t know if 1/3 G is enough to ensure long term stays are healthy nor if humans can have kids in that gravity well with an ethical long term outlook.And I’m not talking about survival of the newborns (which is most likely possible) but quality of life. If they are confined on Mars forever it begets the question if we should do it in the first place.And if people can’t be born there Mars doesn’t have a future.Nevertheless I believe we will know one way or another. As soon as humans arrive there some of them will let nature follow its course and then we will start getting the answer. That will be the big news scandal shortly after we arrive: the first baby born on Mars!

  29. You don’t mine the Moon for carbon. You bring it in (at first from Earth, later from the asteroids or elsewhere). A fully-fueled BFS takes 240 tons of methane (plus 860 tons of oxygen is the 1100 tons methalox that I wrote earlier). If you want to return it empty, it would take less, but if you have a BFS sitting on the tarmac, why not use it to ship useful cargo back to LEO? So out of those 240 tons of methane, 60 tons are hydrogen. That’s an extra 60 tons of other cargo that you can bring if you take along only the carbon. Even if you bring just enough carbon to return an empty BFS, you still probably save a few tons by not carrying hydrogen – a few tons that you can use for much more useful cargo. Note that the BFR capacity is 150 ton **from Earth to LEO**. If you fill it up in LEO, it could probably haul more to the Moon (limited by volume). More realistically, you’d probably send two BFS’s, one filled with cargo, one with carbon (or one filled 50/50). Make as much methalox as you can out of that carbon, then send as much cargo back as that methalox would allow. IMO, methalox is the single most valuable thing that we can use Lunar hydrogen for (more specifically, Lunar water). It would let us bootstrap the infrastructure in cislunar space and beyond, which would pay back huge dividends in the medium to long term. The metal byproducts help with that too. Once you have the infrastructure in place, you no longer need to worry about Lunar water running out, since you can bring in more from elsewhere (asteroids etc). As for a colony, even a million person colony would probably need less than 10 million tons of water (out of the estimated 600+ million tons). 10 tons per person (= 10 m^3 = 10000 L) is pretty generous, I think. And keep in mind that it would take a long time to build up such a large colony.

  30. You don’t mine the Moon for carbon. You bring it in (at first from Earth later from the asteroids or elsewhere). A fully-fueled BFS takes 240 tons of methane (plus 860 tons of oxygen is the 1100 tons methalox that I wrote earlier). If you want to return it empty it would take less but if you have a BFS sitting on the tarmac why not use it to ship useful cargo back to LEO?So out of those 240 tons of methane 60 tons are hydrogen. That’s an extra 60 tons of other cargo that you can bring if you take along only the carbon. Even if you bring just enough carbon to return an empty BFS you still probably save a few tons by not carrying hydrogen – a few tons that you can use for much more useful cargo.Note that the BFR capacity is 150 ton **from Earth to LEO**. If you fill it up in LEO it could probably haul more to the Moon (limited by volume). More realistically you’d probably send two BFS’s one filled with cargo one with carbon (or one filled 50/50). Make as much methalox as you can out of that carbon then send as much cargo back as that methalox would allow.IMO methalox is the single most valuable thing that we can use Lunar hydrogen for (more specifically Lunar water). It would let us bootstrap the infrastructure in cislunar space and beyond which would pay back huge dividends in the medium to long term. The metal byproducts help with that too. Once you have the infrastructure in place you no longer need to worry about Lunar water running out since you can bring in more from elsewhere (asteroids etc).As for a colony even a million person colony would probably need less than 10 million tons of water (out of the estimated 600+ million tons). 10 tons per person (= 10 m^3 = 10000 L) is pretty generous I think. And keep in mind that it would take a long time to build up such a large colony.

  31. I thought the current state of play was that a NTR running water still have a terrible ISP? About 200 or something. You’d be better off with methalox.

  32. I thought the current state of play was that a NTR running water still have a terrible ISP? About 200 or something. You’d be better off with methalox.

  33. I would say that 1. Setting up and getting O’Neil stations running in Earth Orbit is 95% of the tech and infrastructure development that you need to get them running in the Asteroid belt, but much easier to start with because it’s so much closer in both time and deltaV. (Bulk material either brought in from Asteroids, launched from the moon or even Earth to begin with.) 2. Once you’ve got them working safely and reliably in Earth Orbit, them moving them out to the Asteroids/Mars-Orbit/Venus orbit where ever is strap on a rocket/ion-drive/solar-sail and go. 3. Once you’re making O’Neil stations and have several of them around the solar system you are probably in a much safer “eggs in multiple baskets” situation than just having Earth and Mars. 4. THEN you can try making them out in the rocks. Now that you’ve ironed out the bugs.

  34. I would say that1. Setting up and getting O’Neil stations running in Earth Orbit is 95{22800fc54956079738b58e74e4dcd846757aa319aad70fcf90c97a58f3119a12} of the tech and infrastructure development that you need to get them running in the Asteroid belt but much easier to start with because it’s so much closer in both time and deltaV. (Bulk material either brought in from Asteroids launched from the moon or even Earth to begin with.)2. Once you’ve got them working safely and reliably in Earth Orbit them moving them out to the Asteroids/Mars-Orbit/Venus orbit where ever is strap on a rocket/ion-drive/solar-sail and go.3. Once you’re making O’Neil stations and have several of them around the solar system you are probably in a much safer eggs in multiple baskets”” situation than just having Earth and Mars.4. THEN you can try making them out in the rocks. Now that you’ve ironed out the bugs.”””

  35. One nice thing about being months away is that the plague ship dies before it reaches you.” Works for Ebola, not for AIDS

  36. One nice thing about being months away is that the plague ship dies before it reaches you.””Works for Ebola”””” not for AIDS”””

  37. But you run into the problems of weightlessness on the Moon and the insanely corrosive and massively hazardous moon dust. Mars has enough of a atmosphere to wear down the particles as well as enough of a gravity well to dial down on the worst effects of reduced gravity.

  38. But you run into the problems of weightlessness on the Moon and the insanely corrosive and massively hazardous moon dust.Mars has enough of a atmosphere to wear down the particles as well as enough of a gravity well to dial down on the worst effects of reduced gravity.

  39. A BFS can land on the moon with enough methane for the return flight and refuel with Lunar O2. It doesn’t dramatically impact the payload delivered to the moon to take the return methane. By mass O2 is more than methane and it is pretty easy to make lunar O2. The problem is that the moon doesn’t have significant carbon deposits so it is hard to find carbon to make methane and it would be very energy intensive to farm diluted carbon or hydroxyls- much like mining for gold by simply sluicing all the rock in all the rivers of Earth would be difficult. Sure there is gold in there in small quantities but the energy required to harvest it is immense. The same goes for hydoxyls that have been distributed in regolith by the solar wind which are everywhere but at the same time difficult to harvest. I imagine that Lunar water is used for fuel in the early days of a colony and then as colonies grow it finds other uses for food, industry, etc. Once the moon’s water is gone then it is gone forever.

  40. A BFS can land on the moon with enough methane for the return flight and refuel with Lunar O2. It doesn’t dramatically impact the payload delivered to the moon to take the return methane. By mass O2 is more than methane and it is pretty easy to make lunar O2.The problem is that the moon doesn’t have significant carbon deposits so it is hard to find carbon to make methane and it would be very energy intensive to farm diluted carbon or hydroxyls- much like mining for gold by simply sluicing all the rock in all the rivers of Earth would be difficult. Sure there is gold in there in small quantities but the energy required to harvest it is immense. The same goes for hydoxyls that have been distributed in regolith by the solar wind which are everywhere but at the same time difficult to harvest.I imagine that Lunar water is used for fuel in the early days of a colony and then as colonies grow it finds other uses for food industry etc. Once the moon’s water is gone then it is gone forever.

  41. Btw, what is Lunar water/hydrogen so valuable for, other than the methalox process I outlined in my other reply? – Lunar oxide processing would use water catalytically: split the water, react the hydrogen with the oxides to reduce the oxides and recover the water. That doesn’t take a lot of water, and you get the water back when you’re done. – You may want to use the hydrogen for other chemistry, but then you need to ask yourself: is this the best place to do such chemistry? – Mining equipment can be teleoperated from Earth, so doesn’t need a lot of personnel. – For a colony, oxygen would come from the oxides and should be recycled. – For shielding you’d use regolith, not water. The only thing I can think of is food farming and drinking water, but the water that’s used up for that gets excreted back in urine and breath (and some sweat), and should be collected and recycled. Unless you want a really large colony, that doesn’t take that much water either, if you’re not being wasteful.

  42. Btw what is Lunar water/hydrogen so valuable for other than the methalox process I outlined in my other reply?- Lunar oxide processing would use water catalytically: split the water react the hydrogen with the oxides to reduce the oxides and recover the water. That doesn’t take a lot of water and you get the water back when you’re done.- You may want to use the hydrogen for other chemistry but then you need to ask yourself: is this the best place to do such chemistry?- Mining equipment can be teleoperated from Earth so doesn’t need a lot of personnel.- For a colony oxygen would come from the oxides and should be recycled.- For shielding you’d use regolith not water.The only thing I can think of is food farming and drinking water but the water that’s used up for that gets excreted back in urine and breath (and some sweat) and should be collected and recycled. Unless you want a really large colony that doesn’t take that much water either if you’re not being wasteful.

  43. Actually, a planet killer asteroid would probably fill near Earth space with enough junk to make life kind of dangerous for decades. But I was thinking in terms of threats like war and/or new pandemic diseases. One nice thing about being months away is that the plague ship dies before it reaches you.

  44. Actually a planet killer asteroid would probably fill near Earth space with enough junk to make life kind of dangerous for decades. But I was thinking in terms of threats like war and/or new pandemic diseases.One nice thing about being months away is that the plague ship dies before it reaches you.

  45. Vuukle stripped the pluses from the reaction equation. That’s just…. wow. In a really bad way. It should read: C 4 (plus) H2O –> CH4 (plus) 2 O2 (plus) 2 H2

  46. Vuukle stripped the pluses from the reaction equation. That’s just…. wow. In a really bad way.It should read: C 4 (plus) H2O –> CH4 (plus) 2 O2 (plus) 2 H2

  47. That really depends on how much water there is vs how much we need. Unless there’s a real shortage, what you want to be doing is bring only the carbon for the return trip, and make the methalox in situ. The reaction is C + 4 H2O –> CH4 + 2 O2 + 2 H2, which leaves an excess of hydrogen byproduct. You then react this hydrogen with lunar soil (oxides) to recover half the water and get metal byproducts. This maximizes the amount of cargo that you can deliver, and adds the valuable byproducts. If there’s a lot more water than we need for Lunar uses, then you scale this up to produce methalox for LEO and other locations. Though depending on where the methalox will be used, it may make more sense to export the unprocessed water and oxides, and make the methalox there (LEO is one such location). The current estimate based on Chandrayaan-1 data is 600 million tons of ice in craters on the Moon’s north pole. There may be more craters with ice, plus there’s the south pole and the low concentration of hydroxides everywhere else. This still needs to be confirmed, but if it is, I think that’s enough to export methalox. Each ton of water produces 2.2 tons of metalox by the above process. It takes 1100 tons of methalox to fully fuel a BFS, so 500 tons of water. If we used all the Lunar water only for methalox (which we probably won’t), that’s 1.2 million fully-fueled BFS’s from just the north pole. That should be enough to establish asteroid mining, both for methalox production and other uses, including Moon supplies.

  48. That really depends on how much water there is vs how much we need. Unless there’s a real shortage what you want to be doing is bring only the carbon for the return trip and make the methalox in situ. The reaction is C + 4 H2O –> CH4 + 2 O2 + 2 H2 which leaves an excess of hydrogen byproduct. You then react this hydrogen with lunar soil (oxides) to recover half the water and get metal byproducts. This maximizes the amount of cargo that you can deliver and adds the valuable byproducts.If there’s a lot more water than we need for Lunar uses then you scale this up to produce methalox for LEO and other locations. Though depending on where the methalox will be used it may make more sense to export the unprocessed water and oxides and make the methalox there (LEO is one such location).The current estimate based on Chandrayaan-1 data is 600 million tons of ice in craters on the Moon’s north pole. There may be more craters with ice plus there’s the south pole and the low concentration of hydroxides everywhere else. This still needs to be confirmed but if it is I think that’s enough to export methalox.Each ton of water produces 2.2 tons of metalox by the above process. It takes 1100 tons of methalox to fully fuel a BFS so 500 tons of water. If we used all the Lunar water only for methalox (which we probably won’t) that’s 1.2 million fully-fueled BFS’s from just the north pole. That should be enough to establish asteroid mining both for methalox production and other uses including Moon supplies.

  49. Lunar H20 is too valuable to turn in to rocket fuel. (unless there are vast underground ice reserves which I sincerely doubt). The Methalox supply chain can leverage Lunar ISRU O2 and bring enough Methane for the return trip from the Moon (easier once you drop off your cargo). Lunar Hydrogen is too valuable to shoot out a rocket nozzle.

  50. Lunar H20 is too valuable to turn in to rocket fuel. (unless there are vast underground ice reserves which I sincerely doubt).The Methalox supply chain can leverage Lunar ISRU O2 and bring enough Methane for the return trip from the Moon (easier once you drop off your cargo). Lunar Hydrogen is too valuable to shoot out a rocket nozzle.

  51. Yep completely agree. I intentionally used Mr Musk’s super optimistic time. A single BFS brings 10x-30x-80x more “stuff” to the Moon compared to Mars. Because the name of the game is throughput.

  52. Yep completely agree. I intentionally used Mr Musk’s super optimistic time.A single BFS brings 10x-30x-80x more stuff”” to the Moon compared to Mars.Because the name of the game is throughput.”””

  53. 30 days is unlikely any time soon – I think that was one of Elon’s low-ball ‘best case’ estimates. 100 days is somewhat more realistic for a fast human mission that trades off mass for speed. And if you’re considering cargo, probably more like 150-250 days. So 30x to 80x.

  54. 30 days is unlikely any time soon – I think that was one of Elon’s low-ball ‘best case’ estimates. 100 days is somewhat more realistic for a fast human mission that trades off mass for speed. And if you’re considering cargo probably more like 150-250 days. So 30x to 80x.

  55. Hydrogen on the Moon is found in water ice in permanently shadowed areas. There is also a low concentration of hydroxides all over the surface, since the lunar oxides are bombarded by protons from the solar wind. It’s not an abundance of hydrogen, but enough for our near-term needs.

  56. Hydrogen on the Moon is found in water ice in permanently shadowed areas. There is also a low concentration of hydroxides all over the surface since the lunar oxides are bombarded by protons from the solar wind. It’s not an abundance of hydrogen but enough for our near-term needs.

  57. Radiation can be solved with a few meters of Martian rocks and soil, which are found everywhere on the planet.” Precisely. I don’t know why this is such a hang up for people. Radiation protection on the Moon, Mars, and everywhere else is basically dig a hole and make an underground civilization. And yet we are tortured with NASA mars base concept art that shows off three story SOHO lofts. Seriously folks Mr Musk owns a tunneling company… Maybe I am biased (being a claustrophile).

  58. Radiation can be solved with a few meters of Martian rocks and soil” which are found everywhere on the planet.””Precisely. I don’t know why this is such a hang up for people. Radiation protection on the Moon”” Mars”” and everywhere else is basically dig a hole and make an underground civilization. And yet we are tortured with NASA mars base concept art that shows off three story SOHO lofts.Seriously folks Mr Musk owns a tunneling company… Maybe I am biased (being a claustrophile).”””

  59. I’m currently enamored with the idea of a Mars-Moon trade circuit using Nuclear Thermal Rockets that go straight from Mars to A Earth-Moon Lagrange base carrying useful stuff that the Moon doesn’t have. NTR’s can use Martian water as their propellant for the round trip.

  60. I’m currently enamored with the idea of a Mars-Moon trade circuit using Nuclear Thermal Rockets that go straight from Mars to A Earth-Moon Lagrange base carrying useful stuff that the Moon doesn’t have.NTR’s can use Martian water as their propellant for the round trip.

  61. Making an O’neil cylinder is definitely version 2.0 of space exploration. The problem is that while the Moon is close and Mars is 10x further away (in terms of travel time) the asteroids are yet further away still. The supply chain is stretched and even with ISRU and 3D printing you need to send goods. Moon makes good sense if you think in terms of how much mass you can land per day. It isn’t unreasonable to land one BFS per day on the Moon, takes 10x as many BFS to land one per day on Mars. The asteroid belts probably take 20x as many BFS in flight to arrive once per day. So the same infrastructure that sends one BFS to the asteroid belt per day can land 20 BFS on the moon each day. It is just a function of proximity and chemical fuel. Also the Moon isn’t going to get hammered by anything that destroys earth. If you are super concerned want just settle the far side and anything that destroys Earth needs to go through the moon to reach the far side and destroy your colony. Of course on the down side the moon lacks lots of useful things like Carbon, Nitrogen, Hydrogen, etc.

  62. Making an O’neil cylinder is definitely version 2.0 of space exploration. The problem is that while the Moon is close and Mars is 10x further away (in terms of travel time) the asteroids are yet further away still. The supply chain is stretched and even with ISRU and 3D printing you need to send goods.Moon makes good sense if you think in terms of how much mass you can land per day. It isn’t unreasonable to land one BFS per day on the Moon takes 10x as many BFS to land one per day on Mars. The asteroid belts probably take 20x as many BFS in flight to arrive once per day.So the same infrastructure that sends one BFS to the asteroid belt per day can land 20 BFS on the moon each day.It is just a function of proximity and chemical fuel. Also the Moon isn’t going to get hammered by anything that destroys earth. If you are super concerned want just settle the far side and anything that destroys Earth needs to go through the moon to reach the far side and destroy your colony.Of course on the down side the moon lacks lots of useful things like Carbon Nitrogen Hydrogen etc.

  63. Daily throughput of kg to the Moon is 10x the throughput of kg to Mars. Mostly because you need 10x fewer BFS ships to sustain a similar throughput to the moon. (30 day trip vs 3 day trip) Meaning that the infrastructure for a colony of 200 on Mars results in a colony of 2000 on the moon.

  64. Daily throughput of kg to the Moon is 10x the throughput of kg to Mars.Mostly because you need 10x fewer BFS ships to sustain a similar throughput to the moon. (30 day trip vs 3 day trip)Meaning that the infrastructure for a colony of 200 on Mars results in a colony of 2000 on the moon.

  65. Earth orbit and the Moon are close enough that many potential causes of human extinction on Earth would take out a colony there, too. Distance is security in many cases. I’d favor the asteroid belt, myself, but “he who pays the piper”.

  66. Earth orbit and the Moon are close enough that many potential causes of human extinction on Earth would take out a colony there too. Distance is security in many cases. I’d favor the asteroid belt myself but he who pays the piper””.”””

  67. > If there were resources, or some sort of industrial advantage to be gained by manufacturing on Mars Mars had active geology and water for about a billion years. Therefore it has certain minerals and ores in quantity that asteroids do not. Asteroids, on the other hand, have *different* minerals and ores. This serves as the basis of trade, where each supplies what the other lacks. Once Mars starts getting developed, a transportation system can be built. Pavonis Mons sits on the equator. You have about 120 km of western slope available for an electromagnetic accelerator. At 6 g’s (for people) you would reach 3,795 m/s, which is 480 m/s more than the 3314 m/s needed for low orbit. Once built, you can efficiently deliver people and cargo to orbit. The other direction is relatively easy via atmospheric braking. Higher orbits have the advantage in energy, since there is little or no night and no dust scattering, so you have about 3 times the average solar flux. That would be your likely location for industry.

  68. > If there were resources or some sort of industrial advantage to be gained by manufacturing on MarsMars had active geology and water for about a billion years. Therefore it has certain minerals and ores in quantity that asteroids do not. Asteroids on the other hand have *different* minerals and ores. This serves as the basis of trade where each supplies what the other lacks.Once Mars starts getting developed a transportation system can be built. Pavonis Mons sits on the equator. You have about 120 km of western slope available for an electromagnetic accelerator. At 6 g’s (for people) you would reach 3795 m/s which is 480 m/s more than the 3314 m/s needed for low orbit. Once built you can efficiently deliver people and cargo to orbit. The other direction is relatively easy via atmospheric braking.Higher orbits have the advantage in energy since there is little or no night and no dust scattering so you have about 3 times the average solar flux. That would be your likely location for industry.

  69. Musk’s stated goal of colonization is to have a back-up plan for humanity in case something happens to the earth. For me, it makes far less sense to colonize Mars for this purpose than it does to build space stations around the earth or on the moon first. It’s just more cost effective than going all the way to Mars. Colonization is also the wrong word to use. Exploration and risk management is probably more accurate given the stated goal. If there were resources, or some sort of industrial advantage to be gained by manufacturing on Mars then I could see the logic of “colonization”. Otherwise, we’re just building a seed-bank for the time being.

  70. Musk’s stated goal of colonization is to have a back-up plan for humanity in case something happens to the earth. For me it makes far less sense to colonize Mars for this purpose than it does to build space stations around the earth or on the moon first. It’s just more cost effective than going all the way to Mars. Colonization is also the wrong word to use. Exploration and risk management is probably more accurate given the stated goal. If there were resources or some sort of industrial advantage to be gained by manufacturing on Mars then I could see the logic of colonization””. Otherwise”””” we’re just building a seed-bank for the time being.”””

  71. > what are the colonists gong to… do? What have colonists ever done, anywhere, through history? Build a place to live, produce food. On Mars you also have to add “Generate air”. Beyond that, build up some export products to pay for continued deliveries from Earth. That could be as simple as “reality TV” from Mars, which wouldn’t require much they didn’t already have. So the first group to reach Mars will be high-tech equivalents of construction workers, farmers, and chemical plant operators (for the air). Note that the article title is about creating a colony, which is not the same as a research base like we have at the South Pole on Earth. Colonists are people who have moved to a new place to live there permanently. Scientists at a research station or base are typically temporary. That imposes different design requirements on what you build. All of space, and even some places on Earth, don’t have suitable atmosphere for people. The most common one you are likely to encounter is an airplane at 10 km altitude. The air is too cold and low pressure for people, so we artificially create an atmosphere in the cabin. The space station in low orbit needs to supply about 0.3 atmospheres more pressure than an airplane, and Mars is a similar problem. Unlike low orbit, Mars has an atmosphere which contains oxygen in the form of CO2, so it is actually an easier problem. Radiation can be solved with a few meters of Martian rocks and soil, which are found everywhere on the planet. Gravity may or may not be a problem for colonists. We have no experience with long-term low gravity. We do for zero gravity. If we need it, we can generate it artificially with rotation.

  72. > what are the colonists gong to… do? What have colonists ever done anywhere through history? Build a place to live produce food. On Mars you also have to add Generate air””. Beyond that”””” build up some export products to pay for continued deliveries from Earth. That could be as simple as “”””reality TV”””” from Mars”” which wouldn’t require much they didn’t already have.So the first group to reach Mars will be high-tech equivalents of construction workers farmers and chemical plant operators (for the air).Note that the article title is about creating a colony which is not the same as a research base like we have at the South Pole on Earth. Colonists are people who have moved to a new place to live there permanently. Scientists at a research station or base are typically temporary. That imposes different design requirements on what you build.All of space and even some places on Earth don’t have suitable atmosphere for people. The most common one you are likely to encounter is an airplane at 10 km altitude. The air is too cold and low pressure for people so we artificially create an atmosphere in the cabin. The space station in low orbit needs to supply about 0.3 atmospheres more pressure than an airplane and Mars is a similar problem. Unlike low orbit Mars has an atmosphere which contains oxygen in the form of CO2 so it is actually an easier problem.Radiation can be solved with a few meters of Martian rocks and soil which are found everywhere on the planet. Gravity may or may not be a problem for colonists. We have no experience with long-term low gravity. We do for zero gravity. If we need it”” we can generate it artificially with rotation.”””

  73. looking at the big picture all at once, it can feel like an impossible venture. Other than a habitat that could sustain life, humanity literally started with nothing. Then, over time, the foundations of civilization were set and then built upon. The same will happen with the Mars colonization efforts. A few will go at first and a few others will follow over time and slowly lay the foundation for the increasing numbers that will follow them, to build upon. Taken in bite size chunks, we can do this.

  74. looking at the big picture all at once it can feel like an impossible venture. Other than a habitat that could sustain life humanity literally started with nothing. Then over time the foundations of civilization were set and then built upon. The same will happen with the Mars colonization efforts. A few will go at first and a few others will follow over time and slowly lay the foundation for the increasing numbers that will follow them to build upon. Taken in bite size chunks we can do this.

  75. As much as I love the idea of humans becoming an interplanetary species, colonizing Mars sort of feels weird. Looking pass all the technical hurdles (like the radiation, atmosphere, low gravity etc. etc.) what are the colonists gong to… do? Are they all scientists taking samples or are they going to try to form an actual working society there? What if no plumbers want to come? Or kindergarten teachers? I mean, I want to see it happen and work, but I’m sort of worried it has too many problems and just won’t work. We’ll see I guess, I’m definitely not saying we shouldn’t try.

  76. As much as I love the idea of humans becoming an interplanetary species colonizing Mars sort of feels weird. Looking pass all the technical hurdles (like the radiation atmosphere low gravity etc. etc.) what are the colonists gong to… do? Are they all scientists taking samples or are they going to try to form an actual working society there? What if no plumbers want to come? Or kindergarten teachers?I mean I want to see it happen and work but I’m sort of worried it has too many problems and just won’t work. We’ll see I guess I’m definitely not saying we shouldn’t try.

  77. Actually you would send cargo and people in different relays then. Nice delta V efficient burns for the cargo and fast trips for the people.

  78. I would speculate that current medical tech means that we can deal with fast, aggressive acute plagues a lot better than we can currently deal with slow, insidious, subtle diseases that take years to even show symptoms.

    That is certainly what seems to be the big issue these days, if you look at death rates in the industrialised countries.

  79. That wouldn’t be enough. You’d need to multiply Mars’ mass by ~10 times to get Earth-like gravity. Just a few asteroids’ worth of mass isn’t going to make any difference.

  80. Development of what? A colony? A colony should be recycling as much of its water as it can, so the amount used is roughly constant, minus some minimal losses and leaks. Evaporated water can be condensed easily on the Moon. Liquid water can be collected. Dirty water is easy to evaporate, and the vapor condensed into clean water. Water taken up by plants is either eaten and secreted, or composted and evaporated (depending which part of the plant). So it isn’t lost either.

    I don’t know how the ISS compares, but assuming 10 tons of water per person, it’s 10 million tons initial supply for a 1 million person colony. It’ll take a while to even get started, and further to build up, meanwhile the technology can be improved to minimize losses. So let’s say we can get ~10% losses per year, that’s 1 million tons per year. 20 years later maybe it’ll drop to 5% loss or 0.5 a million tons per year. Another 50 years maybe it can drop to 1% per year, or 0.1 million.

    So 10 mil initial plus 20 years times 1 mil/year plus 50 years times 0.5 mil/year is 55 million tons for the first 70 years. Out of the Moon’s 600 plus million tons (if confirmed). By that time we should have the infrastructure to import from elsewhere, but the colony would be pretty well developed already.

    For industry you generally want to avoid processes that treat the water as a consumable, unless it generates enough value to justify that. For example, reduction of Lunar oxides would use the water catalytically. You get the water back at the end. Waste streams in other processes can be recycled as above.

    For developing the cislunar-and-beyond infrastructure – sure, we could continue developing it far further than what Lunar water alone would allow. But the Lunar water should give us a good start.

  81. If gravity is an issue one possability is to set up several solar powered boulder catapults or solar powered canons that fire boulders to bombard mars. All reloaded by solar powered boulder collector robots. Place them on mars moons and on the amor asteroids all of having a goal of sending material to mars. Over time that would increase its mass. If could find an amor asteroid with ice could fill up inflateables with liquid to send to mars. Some of the liquid could be used as fuel to get the craft to mars. Hopefully some of these ideas will help to terraform mars.

  82. To warm mars. First put reflective material on phobos that will create more heat and light on mars for easier terraforming.

  83. Most illustrations of a Mars habitat dome ignore the realities of structural design and radiation protection. The inside pressure, assuming it is sea-level Earth pressure, generates 27 tons/square meter of net lift due to the lower outside pressure. You therefore need minimal structural mass when the weight of the dome equals the lifting force. Otherwise the dome needs to be anchored to a heavy foundation to counter the lifting force.

    27 tons per square meter works out to 10 meters of solid rock, or quartz glass if you want transparency. Either will provide adequate radiation shielding. Since Mars’ solar flux is a lot lower than Earth’s, what will likely be done is pile rock over the top of the dome, but leave windows around the rim. The windows will let in extra light from outside reflectors, which will bring up the total light level to Earth-normal. Then you can fill up the dome with plants for agriculture or just to have it look nice.

    Tunnels are fine for workshops and utility functions, and as emergency shelters, but it would be nice to have some “outdoorsy” spaces too.

    If the dome weight equals the internal lifting force, there is in principle no limit to how big you can make them. You need some structure to keep it from drifting around and flexing, but basically it is floating on air and isn’t limited like domes on Earth, which have equal pressure inside and outside. In the Earth case, they have to support their own weight, which limits their size.

  84. > The problem is that the moon doesn’t have significant carbon deposits

    This is why you want to mine Near Earth Asteroids. The “Carbonaceous” type contains up to 20% carbon compounds and water. This asteroid type is fairly common – Both Ryugu and Bennu, the two being visited by probes this year, are that type.

    Assuming you set up a propellant depot in Lunar orbit, your BFS can tank up there, then land and have enough propellant to take off again.

  85. > the asteroids are yet further away still.

    That’s not correct. The Main Belt is farther than Mars, but there are already 18,500 known “Near Earth Asteroids” which come closer than 1.3 AU to the Sun. That puts them closer than midway to Mars.

    > Of course on the down side the moon lacks lots of useful things like Carbon, Nitrogen, Hydrogen, etc.

    This is why you want to exploit the Near Earth Asteroids *and* the Moon. Each has resources the other is short on.

  86. A lot depends on what human low-G tolerance actually is, and, seriously, we need to know BEFORE we start colonizing.

    If 1/3G is enough, fine, Mars is a great prospect. If you need more, ironically you’re better off on the Moon and the asteroids, because large scale habitable centrifuges are easier to build without an atmosphere getting in the way.

    But, one way or the other, we need to find out.

  87. I don’t think you’re biased. It seems obvious that, except for exploration and maintenance of essential surface equipment, both Martian and Lunar civilizations would be underground. At least until Martian terraforming had gotten far enough along that you could get by outside without a pressure suit. But by then they’d probably just be used to building underground.

    Probably the first thing you want to put in place for a Martian colony is a SPS. All that dust, you don’t want to do the solar power on the surface, that’s been proven. And some local thermal reactors to keep emergency systems going in the event something interrupts the beamed power.

  88. I think we’ll find that you can live there but the lifespan will be less.
    Any future Martians will know this and be good with it. The same way
    people smoke knowing the dangers.
    In the long term, I think it could be the new Florida. Seniors whose mobility has been diminished will find
    it easier in the reduced gravity.

  89. We don’t know if 1/3 G is enough to ensure long term stays are healthy, nor if humans can have kids in that gravity well with an ethical long term outlook.

    And I’m not talking about survival of the newborns (which is most likely possible), but quality of life. If they are confined on Mars forever, it begets the question if we should do it in the first place.

    And if people can’t be born there, Mars doesn’t have a future.

    Nevertheless, I believe we will know one way or another. As soon as humans arrive there, some of them will let nature follow its course and then we will start getting the answer. That will be the big news scandal shortly after we arrive: the first baby born on Mars!

  90. You don’t mine the Moon for carbon. You bring it in (at first from Earth, later from the asteroids or elsewhere). A fully-fueled BFS takes 240 tons of methane (plus 860 tons of oxygen is the 1100 tons methalox that I wrote earlier). If you want to return it empty, it would take less, but if you have a BFS sitting on the tarmac, why not use it to ship useful cargo back to LEO?

    So out of those 240 tons of methane, 60 tons are hydrogen. That’s an extra 60 tons of other cargo that you can bring if you take along only the carbon. Even if you bring just enough carbon to return an empty BFS, you still probably save a few tons by not carrying hydrogen – a few tons that you can use for much more useful cargo.

    Note that the BFR capacity is 150 ton **from Earth to LEO**. If you fill it up in LEO, it could probably haul more to the Moon (limited by volume). More realistically, you’d probably send two BFS’s, one filled with cargo, one with carbon (or one filled 50/50). Make as much methalox as you can out of that carbon, then send as much cargo back as that methalox would allow.

    IMO, methalox is the single most valuable thing that we can use Lunar hydrogen for (more specifically, Lunar water). It would let us bootstrap the infrastructure in cislunar space and beyond, which would pay back huge dividends in the medium to long term. The metal byproducts help with that too. Once you have the infrastructure in place, you no longer need to worry about Lunar water running out, since you can bring in more from elsewhere (asteroids etc).

    As for a colony, even a million person colony would probably need less than 10 million tons of water (out of the estimated 600+ million tons). 10 tons per person (= 10 m^3 = 10000 L) is pretty generous, I think. And keep in mind that it would take a long time to build up such a large colony.

  91. I thought the current state of play was that a NTR running water still have a terrible ISP? About 200 or something. You’d be better off with methalox.

  92. I would say that
    1. Setting up and getting O’Neil stations running in Earth Orbit is 95% of the tech and infrastructure development that you need to get them running in the Asteroid belt, but much easier to start with because it’s so much closer in both time and deltaV. (Bulk material either brought in from Asteroids, launched from the moon or even Earth to begin with.)
    2. Once you’ve got them working safely and reliably in Earth Orbit, them moving them out to the Asteroids/Mars-Orbit/Venus orbit where ever is strap on a rocket/ion-drive/solar-sail and go.
    3. Once you’re making O’Neil stations and have several of them around the solar system you are probably in a much safer “eggs in multiple baskets” situation than just having Earth and Mars.
    4. THEN you can try making them out in the rocks. Now that you’ve ironed out the bugs.

  93. But you run into the problems of weightlessness on the Moon and the insanely corrosive and massively hazardous moon dust.

    Mars has enough of a atmosphere to wear down the particles as well as enough of a gravity well to dial down on the worst effects of reduced gravity.

  94. A BFS can land on the moon with enough methane for the return flight and refuel with Lunar O2. It doesn’t dramatically impact the payload delivered to the moon to take the return methane. By mass O2 is more than methane and it is pretty easy to make lunar O2.

    The problem is that the moon doesn’t have significant carbon deposits so it is hard to find carbon to make methane and it would be very energy intensive to farm diluted carbon or hydroxyls- much like mining for gold by simply sluicing all the rock in all the rivers of Earth would be difficult. Sure there is gold in there in small quantities but the energy required to harvest it is immense. The same goes for hydoxyls that have been distributed in regolith by the solar wind which are everywhere but at the same time difficult to harvest.

    I imagine that Lunar water is used for fuel in the early days of a colony and then as colonies grow it finds other uses for food, industry, etc. Once the moon’s water is gone then it is gone forever.

  95. Btw, what is Lunar water/hydrogen so valuable for, other than the methalox process I outlined in my other reply?

    – Lunar oxide processing would use water catalytically: split the water, react the hydrogen with the oxides to reduce the oxides and recover the water. That doesn’t take a lot of water, and you get the water back when you’re done.
    – You may want to use the hydrogen for other chemistry, but then you need to ask yourself: is this the best place to do such chemistry?
    – Mining equipment can be teleoperated from Earth, so doesn’t need a lot of personnel.
    – For a colony, oxygen would come from the oxides and should be recycled.
    – For shielding you’d use regolith, not water.

    The only thing I can think of is food farming and drinking water, but the water that’s used up for that gets excreted back in urine and breath (and some sweat), and should be collected and recycled. Unless you want a really large colony, that doesn’t take that much water either, if you’re not being wasteful.

  96. Actually, a planet killer asteroid would probably fill near Earth space with enough junk to make life kind of dangerous for decades. But I was thinking in terms of threats like war and/or new pandemic diseases.

    One nice thing about being months away is that the plague ship dies before it reaches you.

  97. Vuukle stripped the pluses from the reaction equation. That’s just…. wow. In a really bad way.
    It should read: C 4 (plus) H2O –> CH4 (plus) 2 O2 (plus) 2 H2

  98. That really depends on how much water there is vs how much we need. Unless there’s a real shortage, what you want to be doing is bring only the carbon for the return trip, and make the methalox in situ. The reaction is C + 4 H2O –> CH4 + 2 O2 + 2 H2, which leaves an excess of hydrogen byproduct. You then react this hydrogen with lunar soil (oxides) to recover half the water and get metal byproducts. This maximizes the amount of cargo that you can deliver, and adds the valuable byproducts.

    If there’s a lot more water than we need for Lunar uses, then you scale this up to produce methalox for LEO and other locations. Though depending on where the methalox will be used, it may make more sense to export the unprocessed water and oxides, and make the methalox there (LEO is one such location).

    The current estimate based on Chandrayaan-1 data is 600 million tons of ice in craters on the Moon’s north pole. There may be more craters with ice, plus there’s the south pole and the low concentration of hydroxides everywhere else. This still needs to be confirmed, but if it is, I think that’s enough to export methalox.

    Each ton of water produces 2.2 tons of metalox by the above process. It takes 1100 tons of methalox to fully fuel a BFS, so 500 tons of water. If we used all the Lunar water only for methalox (which we probably won’t), that’s 1.2 million fully-fueled BFS’s from just the north pole. That should be enough to establish asteroid mining, both for methalox production and other uses, including Moon supplies.

  99. Lunar H20 is too valuable to turn in to rocket fuel. (unless there are vast underground ice reserves which I sincerely doubt).

    The Methalox supply chain can leverage Lunar ISRU O2 and bring enough Methane for the return trip from the Moon (easier once you drop off your cargo). Lunar Hydrogen is too valuable to shoot out a rocket nozzle.

  100. Yep completely agree. I intentionally used Mr Musk’s super optimistic time.

    A single BFS brings 10x-30x-80x more “stuff” to the Moon compared to Mars.

    Because the name of the game is throughput.

  101. 30 days is unlikely any time soon – I think that was one of Elon’s low-ball ‘best case’ estimates. 100 days is somewhat more realistic for a fast human mission that trades off mass for speed. And if you’re considering cargo, probably more like 150-250 days. So 30x to 80x.

  102. Hydrogen on the Moon is found in water ice in permanently shadowed areas. There is also a low concentration of hydroxides all over the surface, since the lunar oxides are bombarded by protons from the solar wind. It’s not an abundance of hydrogen, but enough for our near-term needs.

  103. “Radiation can be solved with a few meters of Martian rocks and soil, which are found everywhere on the planet.”

    Precisely. I don’t know why this is such a hang up for people. Radiation protection on the Moon, Mars, and everywhere else is basically dig a hole and make an underground civilization. And yet we are tortured with NASA mars base concept art that shows off three story SOHO lofts.

    Seriously folks Mr Musk owns a tunneling company… Maybe I am biased (being a claustrophile).

  104. I’m currently enamored with the idea of a Mars-Moon trade circuit using Nuclear Thermal Rockets that go straight from Mars to A Earth-Moon Lagrange base carrying useful stuff that the Moon doesn’t have.

    NTR’s can use Martian water as their propellant for the round trip.

  105. Making an O’neil cylinder is definitely version 2.0 of space exploration. The problem is that while the Moon is close and Mars is 10x further away (in terms of travel time) the asteroids are yet further away still. The supply chain is stretched and even with ISRU and 3D printing you need to send goods.

    Moon makes good sense if you think in terms of how much mass you can land per day. It isn’t unreasonable to land one BFS per day on the Moon, takes 10x as many BFS to land one per day on Mars. The asteroid belts probably take 20x as many BFS in flight to arrive once per day.

    So the same infrastructure that sends one BFS to the asteroid belt per day can land 20 BFS on the moon each day.

    It is just a function of proximity and chemical fuel. Also the Moon isn’t going to get hammered by anything that destroys earth. If you are super concerned want just settle the far side and anything that destroys Earth needs to go through the moon to reach the far side and destroy your colony.

    Of course on the down side the moon lacks lots of useful things like Carbon, Nitrogen, Hydrogen, etc.

  106. Daily throughput of kg to the Moon is 10x the throughput of kg to Mars.

    Mostly because you need 10x fewer BFS ships to sustain a similar throughput to the moon. (30 day trip vs 3 day trip)

    Meaning that the infrastructure for a colony of 200 on Mars results in a colony of 2000 on the moon.

  107. Earth orbit and the Moon are close enough that many potential causes of human extinction on Earth would take out a colony there, too. Distance is security in many cases.

    I’d favor the asteroid belt, myself, but “he who pays the piper”.

  108. > If there were resources, or some sort of industrial advantage to be gained by manufacturing on Mars

    Mars had active geology and water for about a billion years. Therefore it has certain minerals and ores in quantity that asteroids do not. Asteroids, on the other hand, have *different* minerals and ores. This serves as the basis of trade, where each supplies what the other lacks.

    Once Mars starts getting developed, a transportation system can be built. Pavonis Mons sits on the equator. You have about 120 km of western slope available for an electromagnetic accelerator. At 6 g’s (for people) you would reach 3,795 m/s, which is 480 m/s more than the 3314 m/s needed for low orbit. Once built, you can efficiently deliver people and cargo to orbit. The other direction is relatively easy via atmospheric braking.

    Higher orbits have the advantage in energy, since there is little or no night and no dust scattering, so you have about 3 times the average solar flux. That would be your likely location for industry.

  109. Musk’s stated goal of colonization is to have a back-up plan for humanity in case something happens to the earth. For me, it makes far less sense to colonize Mars for this purpose than it does to build space stations around the earth or on the moon first. It’s just more cost effective than going all the way to Mars. Colonization is also the wrong word to use. Exploration and risk management is probably more accurate given the stated goal. If there were resources, or some sort of industrial advantage to be gained by manufacturing on Mars then I could see the logic of “colonization”. Otherwise, we’re just building a seed-bank for the time being.

  110. > what are the colonists gong to… do?

    What have colonists ever done, anywhere, through history? Build a place to live, produce food. On Mars you also have to add “Generate air”. Beyond that, build up some export products to pay for continued deliveries from Earth. That could be as simple as “reality TV” from Mars, which wouldn’t require much they didn’t already have.

    So the first group to reach Mars will be high-tech equivalents of construction workers, farmers, and chemical plant operators (for the air).

    Note that the article title is about creating a colony, which is not the same as a research base like we have at the South Pole on Earth. Colonists are people who have moved to a new place to live there permanently. Scientists at a research station or base are typically temporary. That imposes different design requirements on what you build.

    All of space, and even some places on Earth, don’t have suitable atmosphere for people. The most common one you are likely to encounter is an airplane at 10 km altitude. The air is too cold and low pressure for people, so we artificially create an atmosphere in the cabin. The space station in low orbit needs to supply about 0.3 atmospheres more pressure than an airplane, and Mars is a similar problem. Unlike low orbit, Mars has an atmosphere which contains oxygen in the form of CO2, so it is actually an easier problem.

    Radiation can be solved with a few meters of Martian rocks and soil, which are found everywhere on the planet. Gravity may or may not be a problem for colonists. We have no experience with long-term low gravity. We do for zero gravity. If we need it, we can generate it artificially with rotation.

  111. looking at the big picture all at once, it can feel like an impossible venture. Other than a habitat that could sustain life, humanity literally started with nothing. Then, over time, the foundations of civilization were set and then built upon. The same will happen with the Mars colonization efforts. A few will go at first and a few others will follow over time and slowly lay the foundation for the increasing numbers that will follow them, to build upon. Taken in bite size chunks, we can do this.

  112. As much as I love the idea of humans becoming an interplanetary species, colonizing Mars sort of feels weird. Looking pass all the technical hurdles (like the radiation, atmosphere, low gravity etc. etc.) what are the colonists gong to… do? Are they all scientists taking samples or are they going to try to form an actual working society there? What if no plumbers want to come? Or kindergarten teachers?
    I mean, I want to see it happen and work, but I’m sort of worried it has too many problems and just won’t work. We’ll see I guess, I’m definitely not saying we shouldn’t try.

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