PB666

Falcon final burn begins with 3 engines, if I am not mistaken.

sure.

Remember what happened to the challenger. The problem with space X is their stages RTLS (as one possibility of three). Adjacent pads is a personnel problem for those on the lagging launch

hmmm a spaceX, sort of late WWII jet like rocket with a soviet star on it, Musk does seem to be a Jack of all trades.

You could get a boat and go into the bay, though I think range would probably shoo you off.

Not too shabby. If you spent all the money to go down their, $52 is not too much.

This one (or two) http://biosphere2.org/ https://en.wikipedia.org/wiki/Biosphere_2#First_mission https://en.wikipedia.org/wiki/Biosphere_2#Second_mission Of course I could be biased but I think these two studies were a whole lot more evolved and involved relative to what the Mars society is doing. The problem with doing down-scale experimentation, I don't have a problem with that but they have to be scientific. If you want to rent the Astrodome and turn it into a martian landscape (complete with a reproduction of Martian soil down to the shape and size of Martian dust) then that is an experiment with controls. That's not what the Mars society is doing however, they are creating equivalence between living on summer/arctic landscape as the same as living on Mars. Anyway, this stuff will be tossed into the group 1000 times as something of value, its pretty much not.

There is much room for extended runways in the desert. Not so much room in London or Paris, New York or Los Angeles. They can design an aircraft that can haul passengers at Mach 3 (80000 feet ceiling) making any destination on Earth 4 hours away. The problem is that you would need a runway 5 nMiles in length to make it safe to take off and land.

Weren't there two Earth sphere experiments that ditched after a few months. One can dawn a ballerina costume and go out on a salt flat and pretend its a ballet, photoshop it and sell it as a broadway production, someone will buy it. Im not going to disparage the Mars society, but the reality is that their reports need to be distilled into the few grains of value that might be in them. The society is working on peripheral problems, problems that might best be solved by robots. The core problem with Mars is energetics, we cannot produce energy the way we dream that energy can be produced. Almost all the transportation 'fantasy' systems lack a functional working prototype. On the surface your energy is within 60' of the equator and your primary resources are within 20' of the poles. There is no fusion power, and the proposed fission reactor would barely suffice for human needs, let alone production of fuels, or building colonies. 'once we get fusion working we will have . . . . '. But fusion power isn't working, and they have been trying for 50 years which tells us something. Getting ;'stuff' to orbit is not that horrifically expensive anymore. There is no cheap way however to get it to the surface of Mars, getting humans on the surface is plausible, getting them off is not. . . . . . . . dissatisfied with what exists, seeks out stuff that is fantasy and tries to push it off (derail) as equivalent to reality. If we want to talk about ideal circumstances 1. A rotating crew capsule producing 0.39g of centrifugal force at least 15 meters in diameter. 2. A capsule surrounded with a meter of water and a meter of lead, borate, . . . . . to block the cosmic radiation and neutrons 3. A propulsion system capable of moving astronauts to LMO. (In 39 days requiring 10,000 dV) 4. Also able to land on mars. 5. And lift off from Mars and return to LEO. These 5 circumstances are contradictory given current technology, we do not have the energy. Getting food to Mars is a small problem in comparison, there will have to be compromises to human health, to safety, to returnabilitiy.

I wouldn't say a century, but it depends on what level of committment. Lets say 100 fold greater committment from Earth than that devoted to the Apollo mission. Just to make a point, LEDs will be essential to such a colony, but are much more cheaply shipped than made initially on Mars. Other high value equipment likewise. Other things like the housing for equipment, bunk beds, etc. could be made on Mars. As one point was made, its not evident what Mars could send back to Earth that would justify the cost, since even the rarest minerals on Earth are easier to extract here and ship elsewhere on Earth.

Only if you believe Vaporware actually does something other than whip up hype. This doesn't even constitute as hype, NASA has no plan. NASA basically is saying 'we have a whole lot of problems we need to solve before leaving the EM system'. Roughly translated, once they know how to solve the problems, then they we layout their plans to build stuff and then build the infrastructure in space (if they decide to go with fictional fusion) to build such a craft. Right now solar power and light fission reactors are the only viable power source. Even NERVA is off the table because of the need to store liquid hydrogen.

This is NOT a BFR thread, and BFR does not have a stated build capability.

Note that video was made 10 years before the shuttle was cancelled. Right now we don't even have a vessel capable of building a facility capable of building that kind of craft, it will be at least 15 years before we do. More fantasy absent of any supporting facts.

sure.

As part of the package have them spend a week on a Schooner in the Caribbean. Problem solved. Of course for the Boca Chica you could contract out with the local shrimp boats and charter fishermen that run out of Isabel and SPI and pretty much the same effect.

My, my, we must be bored to bring this topic here.

In my mind E2E transport is a sales gimmick, sort of like that attachment that comes with your shop vacuum that you never use because you never figured out what its really for. While Natural gas is available everywhere, if you are liquefying it from point sources off the coast, that's an awful lot of gas for any local pipeline.

Cause where they are going to launch from Boca Chica, which sits about 60 miles from the 3rd largest reserve of natural gas in the country. Natural gas currently is selling for $2.35 per MMBTU (27.096 cubic meters), they are burning off gas in the gulf of Mexico right now. A cubic meter has 16 grams/mole * 1000 liters/22.4 moles per liter of gas, that translates to 0.714 * 27.096 = 19.075kg or $0.12 per kilogram. Thats equivilent to about $0.7 per gallon of gasoline or about 1/3 the price of kerosene. Of course natural gas is not pure methane, so they will have to scrub it. In addition its ISP is 9% higher than RP1 for two equivalent performance engines, this is due to ~1.5 additional C-H bonds relative to kerosene. So in total methane is going to cost them 1/3rd to 1/4th the price. Liquid methane is less dense than RP1 and has a higher storage pressure, so that they will need stronger storage vessels and a wider or taller spacecraft.

you have a BFR thread now. Though it appears there are three amorphous BFR topics. 1. The BFR - interplanetary a. Autonomous mars lander b. Manned mars primary lander c. Manned mars bunch of people lander. 2. The BFR - hypersonic liner. 3. The BFR - transporter. a. Fuel transporter b. Package deliver service.

Generally something to be avoided, ETOPs is a specification for single engine failure over water, for example a mid pacific glide to water landing is the same as a crash, few survivors expected. The hudson river is a bonafida runway, used to be used in the days of transatlantic flights, the pacific ocean is not. The difference between space flight and air flight is that the risk is high, but you don't do it very often. For aircraft the risk is low and people travel alot. The risk of spaceflight still exceeds that of flight, but one expects that risk to fall over time as we learn more about how to manage risk. Where have we seen this problem before, with flight. Crashes of Airplanes back in the 70s was much more common today (in the west), but has gone down over time do to increased use of aircraft. But before the 70s . .going back to the 1930s . . .it was pretty dangerous.

One of the issues of landing on water is one you may not consider. The reason for burning out most or all of the fuel is that kerosene is considered an environmental hazard, and so for craft that do not burn up completely, one does want to limit the amount of kerosene let loose in the saltwater. I think that SpaceX is testing their reentry systems continuously both in fail and normal modes, they are doing this rather intentionally to test the lower bounds of reliable performance so that they are not wasting resources. Again there is no rational for block <5 cores because you want the testing done before deploying block 5 as these will be the bread winners. From a commercial POV you want these to have stellar performance so you can PR the hell out of them.

This means that scientist can prove to other skeptical scientist that they are correct. For example recent experiments offer evidence consistent with the theory of general relativity and Einstein's field equations, but do not offer evidence in support of any theory of quantum gravity. So for example the Ligo offers evidence that supports GR but offers no support of string theory. String theory cannot be proved or disproved and so that neither layman or scientiest are compelled to believe it. GR on the otherhand is difficult to understand and layman are not expected to believe it. The college student is largely expected to understand why other scientist believe GR even if their understanding of field equations does not suffice to prove it to themselves. The graduate level student in physics is expected to know how to execute the field equations and prove it to themselves, and a may participate in projects that provide evidence that prove it. The professors (a portion thereof) are knowledgeable enough to gather the people together to design the experiments (e.g. Ligo) that are also designed to provide the data that supports the theory. The level of understanding depends on the layman, but there is no prophecy in ignorance. For all the false pointers the internet provides it also provides numerous free online courses to learn about science, there is Modern Physics, Advanced Physics, General Relativity, Special Relativity, Quantum Mechanics, Quantum Entanglement, . . . . .So that the layman says I chose not to believe, but then makes no effort to understand, professing a non-truth to others; this is the definition of wanted ignorance . . .its not a realm of science.

I should point out that in my preferential model for transplanetary transfer that somehow gravity is provided for and there is a massive ship that carries humans from Earth to Mars in a fairly well protected spacecraft. This model depends on however fusion as a power source, as we know does not yet exist and may not be feasible in space. But if we assume we could get humans relatively quickly to ES L2 in which they could be transferred to MS L2 and then to Mars fairly quickly one could lower the amount of GCR experienced along the route. Again such a journey only works well if alot of humans are packed in fairly small space. If you can get the transit radiation down, then a Martian colony is possible. The problem is one that should be tested, this doesn't mean it will pave the way for self sufficient colonies. Humans could preferentially travel to mars during periods of lower solar magnetic fields and lower sun-spot activity. In addition males could travel to Mars before the age of 12 to limit testicular SNP accumulations (lowering germline accumulation of SNPs) A necessity IMO is that there must be underground colonization. Colonization on the surface is a non-starter, for research or otherwise. Other aspects. 1. Complete surface robotization of activities. 2. Dust abatement systems (this would including sweep a perimeter around a base of all free dust and placement of dust control systems at the perimeter) 3. A means of cleansing robots free of dust for inspection and repair underground in a pressurizes work environment. The need for a economically viable colony is not a necessity as long as the colony is within an externally sustainable size. The base assumption is that our ability to transport materials to LEO and then to Mars will go down over time, and that the transport costs of non-perishables will be fractional compared to the cost of transporting humans. Consequently the base would be sustained for lengthy periods of time. There is a model in which a colony might achieve a higher level of sustainability, that is if the colony could find a source of geothermal energy (ideally in proximity of a few kilometers from a source of water). In such a model steam and surface radiation can be used to generate electricity required to run the internal systems required to generate light and run greenhouses on LEDs underground. In this model the colonist could provide their own food (using robots to supplement labor) or even greenhouses on the surface with radiation resistent varieties of crops, again managed by robots (though, given the problems with pressurization this is far future stuff). The larger problem, provided a source of water, is not the growing of food. The problem is the conversion of metal and raw earth materials into useful materials. Again, bulk shipments from Earth (or from asteroids) will be a neccesity. The good thing is that Bulk metals are fairly resilient to reentry as long as the user transports them from where they land. What I see is that Mars colonization (non-economically) is a serial and parallel sets of solvable problems. Humans over their history are very good at solving these types of problems and inevitably they will be solved. A concorde is a non-economical way to travel, and yet for a few decades humans traveled on concorde. Of course the flaw in the Concorde is that several problems in supersonic travel went unsolved and overtime it was recognized as problems. So for Mars colonies to survive, problems that develop (in design, in concept, in technology) would need to be solved quickly and in an apolitical manner. Maybe not a government, but a company that runs into a brick wall trying to start a colony. And again, we cannot compare a Martian colony with Jamestown, which had an assumption that the colonist would survive on their own, but the assumption of a research colony would be run in such a way as to test the best ways to survive on its own. So that if the research colony was successful in providing say half of its food, then it could add 25 members based on the provisional alotment of resources. BTW, I think that for certain countries (i.e. China, India) such ethical limitations may not be perceived as the west. If the goal is to claim by habitation/colonization then the ethics fly out the window. My point is lets not close the door on colonization before the research is done. If the research is done and comes up with a no-go, then its probably a no-go. The reason this is not tested in space is that space has the following limitations 1. Unavoidable GCR. 2. Lack of gravity. 3. Confined by pressure (Same on Mars but with the provision that soil underground provides a force to that counters habitation pressure, and vessels can be larger.

I'm talking about a colony, where basically having and raising children is part of the research. Again, non-economic fully sponsered colony testing the bounds of humans in space. The critical problem with Mars is neither the radiation or the low gravity. The problem is the lack of an atmosphere, so its going to be a couple raising one child at a time and much of their duties would be childrearing in nature. Million individuals, no. Think more along the lines of 50 individuals, a tribe. We have tested everything about humans on the ISS but one, reproduction. At some point in time this will become a subject of study.

I don't know if I would go that far. I could see a research colony. But that would be like way far in the future. The problem with colonizing mars is that its a type of confinement that humans are not really used to. Colonies require a sort of venture space, and I can see that if the colony were build deep underground, but a surface colony with children, etc, doesn't sound feasible. Human species needs to set higher aspirations that the current circumstance (consider the debates we have lately). Not too much in there about research or progress.