I get the feeling that you don't understand how numerous, complex, arbitrary, diverse, ambiguous, etc. natural languages are. That phrase, "all languages", doesn't even have a knowable, well-defined meaning, either in theory or in practice.
It would certainly be possible to improve upon Unicode, if you're willing to sacrifice backwards compatibility. However, it will never achieve your stated goal of guaranteeing support for "all languages" just by "throwing in" a new text processing library.
Projects that refuse to invest in internationalization will continue to fail badly at it, regardless of whether they use Unicode, or a "lessons learned" successor encoding.
On many systems, e.g. Windows, w_char is defined as 16 bits, meaning it can only ever support the Unicode Basic Multilingual Plane without hacks.
True UTF-16 supports non-BMP code points just fine, and is not a "hack". In fact, it's actually slightly easier to do so in UTF-16 than with UTF-8 (the only other common Unicode encoding).
The real problem is that there is no single concept in Unicode that maps to the "character" of the old, simple ASCII standard with which most programmers are familiar. Depending on the task at hand, the correct substitute under Unicode may be code units, code points, or graphemes. Ignorant and/or lazy programmers who make incorrect selections between those three are the cause of many Unicode-related bugs.
Also, some important "Unicode" APIs were stabilized before the standard evolved into its present complex form, and cannot be completely fixed for backwards compatibility reasons: notably, the Java standard library and the Win32 API.
These problems persist for the same reason that commercial software usually doesn't even try to support Linux: the additional market share (in dollars, not just users) which can be captured is perceived to be worth less than the cost of properly writing, optimizing, and testing the considerably more complex and slower code required for full Unicode support.
No. Nor would I be stupid enough to assume the price would drop just because the supply increases (processing cost may not drop).
Earth's surface has far, far more deuterium than anyone is interested in buying at current prices, so there is no reason to export deuterium from Mars at all, unless it can be extracted more cheaply there than here.
Do you have any evidence to support your claim that the price is based soley on demand?
I made no such claim. I said the opposite: that demand is low because the price is high.
Evidence for the absurd assertion that the cost would drop to the same a silver if the supply increased by a factor five?
Again, I made no such claim. What I said is that Martian deuterium could be up to five times cheaper to extract because the concentration of deuterium in Martian water is about five times higher than it is on Earth.
Patently and demonstrably you did not ask for a business case
I did exactly that earlier in this thread: #52979631. That's the whole topic of our discussion: how does a Martian colony pay for itself?
Read the source I provided instead of relying of what you skim-read from someone else's outdated opinion.
In order to support your claim (that a Martian colony can make money by selling deuterium to Earth that was produced as a mere by-product of drinking water extraction), you would need to present evidence that a method of enriching deuterium to double-digit percentages has been discovered which is similar in price to a single round of ordinary water purification by reverse osmosis or distillation. Otherwise, the deuterium extraction would cost significant additional resources just like I said, and not qualify as a mere by-product of drinking water extraction.
The abstract of the paper you linked contains no such evidence (neither the system's costs nor the % enrichment of deuterium achieved is described), and I'm not going to read the full paper because it's pay-walled and I'm not spending $40 to settle a Slashdot debate.
Present technology - with which I'm familiar (and not just from reading/.) is too slow for human transport - but viable for unmanned (or short manned) transport.
I've already stated that I believe the cheapest way to mine asteroids would be largely automated. Economically speaking, it makes no sense to send a million people out there "just because"; machines can do the job cheaper, with perhaps a much smaller number of humans overseeing things.
[sigh]Musk's transports are resusable - what are you wrapping your (imaginary) rockets in? Unicorn farts?
Do you think Musk invented the concept of reuse, or that reuse only works if you're on your way to Mars?
Robotic asteroid mining can be done with reusable launchers (perhaps even the ITS itself), transit stages, etc. more easily than manned colonization can. Asteroid mining equipment doesn't need to repeatedly survive the extreme temperatures and G-forces of planetary launch and re-entry; most of it just goes up once and then stays in micro-gravity for its full service life. Re-fueling is done in Earth orbit, or at an asteroid station.
We don't remotely mine the Pilbara because it's not signficantly cheaper...
Again, how is it that you don't understand that visiting Pilbara is dirt cheap compared to visiting Mars? Just because sending people to Pilbara is cheaper than building better robots doesn't mean that sending people to Mars (something which has never even been done before!) is cheaper.
[cough] That's not an "alternative" (therefore it cannot be "viable") - it's just the (current) situation.
And yes, I learned this playing Kerbal Space Program
Kerbal Space Program is great. You have to really work at it to accurately model a system like this though - you need to use all the realism mods, build the system at full size, and use a competent auto-pilot for the landing burn. (Manual landings are difficult and waste a lot of fuel compared to a computerized "suicide burn".)
Someone (not me) has now done this and posted the results on YouTube. Only about ten percent of the first stage's fuel was needed for boost-back and landing.
my original contention was this: "[Apollo] was arguably the pinnacle of manned space capability and we still haven't matched it with modern systems." It's irrefutably true
I think it could be argued that the International Space Station is both more advanced than Apollo, and more relevant to solving the hardest problems associated with colonization: keeping people alive, long-term. Nevertheless, I concede the point as you have narrowly defined it.
but if we looked to airliners which are more comparable, this would be like having intercontinental flights in the 70's, and today we can only fly cross-country, but still have to pay 70% of the original price. Pretty tepid "advancement".
The difference here is that there is a huge market for travelling between continents, because all of them (except Antarctica) are great places to live and work. There is no comparable market for flights to the Moon, because there's not much to do there except enjoy looking around and hope you don't die before it's time to go home.
Judging an industry by how good of a "bridge to nowhere" it maintains is not really fair.
I think this is the classic "if you build it, they will come" scenario...
Perhaps. Musk's transport system has a lot of potential, but I think his impatience (driven by anxiety about his own mortality, I suspect) and laser focus on Mars may damage his cause in the long-term.
If he really wants a self-sustaining, economically independent colony, it would be better to drive the technology forward until that is obviously viable. A colony that is always teetering on the edge of disaster, because it was established prematurely, adds little to the robustness of human civilization, but will still consume tremendous resources during the start-up phase - and maybe indefinitely afterwards, too.
There are plenty of incremental steps that could be pursued to drive R&D and expand the industry, such as near-Earth space tourism (as you suggest), asteroid mining, space-based solar, and small-scale research and exploration colonies that aren't intended to be self-sufficient. All of these things would benefit greatly from a huge reusable rocket like the ITS, without the high probability of catastrophic, deadly, horrendously expensive failure that accompanies a premature large-scale colonization effort.
it's extremely rare on Earth... $2 Billion is not the limit of demand, it's the limit of supply
Do you have evidence for a large pent-up demand for deuterium that would be released by a price drop of less than five times? (That would take it down to about the price of silver.)
the two would be of value for fueling fusion rockets
That's a technology that does not currently exist, and which might not actually use deuterium or tritium when/if it finally gets going.
less than one tenth of what the USA spends annually on the bullshit War on Drugs
This is an irrelevant point of comparison. I'm asking for a business case; you can claim anything is "economically viable" if you're allowed to just steal something else' budget. That argument doesn't tend to convince the people who actually control such budgets, though.
it's just a by-product of potable water production.
This is a ridiculous statement which suggests that you have no idea how deuterium is actually refined, or why it's so expensive. Deuterium will no more be "just a by-product of potable water production" on Mars than it is on Earth.
The concentration of deuterium on Mars is significantly higher than on Earth, but it's still extremely low in absolute terms. Extracting it on Mars will require dedicated machinery and tons of additional energy, just like on Earth. Yes, the amount of additional energy required will be less - but that will be counterbalanced by the generally greater expense of working in a frozen near-vacuum, surrounded by poisonous dust.
Red Herring alert! Can you point to the source of your claim that this fleet won't be waiting for results from surface probes (and many robotic test trips)?!
Musk already decided that we should send one million people there to build a self-sustaining society, even though he himself admitted that he doesn't have any idea how to make that latter part work economically or technologically. That was half the point of his talk...
So in your alternative plan all space exploration will be using theoretical propulsion that starts from this planet... environmentally friendly and sustainable
Electric propulsion (various styles of ion engines and plasma engines) is not "theoretical" - it's in use today on space probes and even commercial satellites - unlike the deuterium-based fusion that your plans seem to depend upon. And yes, it is more environmentally friendly and sustainable because it's literally about ten times as fuel efficient as chemical rockets.
There are various good reasons why Musk didn't select electric propulsion for his proposal, but they mostly revolve around his fixation on putting tons of human beings on the surface of Mars. For mining the Main Belt, most of his reasons do not apply.
I guess that'll push up the price aluminium, good plan
??? What does this have to do with anything I said? Electric engines can run on pretty much any elemental propellant (as long as it's not too reactive), including abundant hydrogen, or any of the noble gases. My proposal almost certainly uses less aluminium than Musk's, since it requires less total up-mass and aerospace stuff tends to use a lot of aluminium for structural purposes.
Moving a million to Mars is achievable - moving a billion is not. We don't have the resources for it, and environmental effects would have a severe impact on those that don't go.
OK... what does that have to do with our discussion? Who suggested moving a billion people to Mars? I certainly didn't.
I'm somewhat familiar with large scale mining and I find your remote mining of asteroids "controlled from Earth, intriguing. I wonder why we don't do that now instead of FIFO to humpies in the P
I realize that's probably not a serious question, but just in case...
People moving around inside a vehicle can shift the centre of mass and induce rotation. For a spacecraft in free fall, this has no meaningful effect on its trajectory, as Kepler's laws aren't sensitive to the orientation of such a small object. However, for a car in contact with the road, tilting the vehicle may cause it to veer to one side because of asymmetric changes in traction, or mechanical interference with the steering system.
As far as I can tell, the worldwide deuterium market is currently less than $2 billion per year, whereas Musk's plan proposes to spend at least $10 billion per year on transportation alone - and obviously there would be many other large costs associated with establishing a self-sufficient mining colony.
The advent of commercial fusion power might change this - or it might not. Maybe proton-boron fusion will beat deuterium as a fuel, or maybe next-generation fast fission reactors and/or solar power will win the market instead. Establishing a trillion dollar (low estimate) colony to service a market that might not ever even exist is foolish.
Besides which, Earth is quite capable of refining its own deuterium, anyway. (Yes, I know that the concentration of deuterium is greater on Mars. It's still super low though, and the difference might not even pay for the added transportation costs - let alone all of the other tremendous overhead associated with building and maintaining a million-person Martian colony for this task.)
knowledge... worth more than anything else
Knowledge of Mars can be acquired through exploration, by sending dozens or hundreds of people instead of a million. Keep the population low enough that Earth can afford to support them long-term, so they can focus on their research and exploration. Colonize later when and if the explorers find resources worth exploiting, or technology advances to the point that self-sufficiency is unambiguously doable.
knowledge about the environment that we won't know until surface probes return results
Why not wait for those results before deciding that we should spend a trillion dollars on settling one million people there?
It's a strawman question (intentional?) that ignores viable access to the asteroids of the Main Belt... it's not about the end-points, it's the points in-between - many of them inhospitable places. All of it driven by trade...
It would be cheaper to skip the million-person Mars colony, and just focus on mining asteroids. Most (all?) of the work can be done automated with supervision from Earth. The Martian surface is an expensive distraction at the bottom of a deep gravity well. Refuelling at Mars is probably unnecessary with electric propulsion, but can be accomplished with way less than a million people there if needed.
In the case of Australia colonisation was originally intended as a means of supporting and claiming a trading base
The Martian surface is not a good trading base for any destination but itself. The relatively deep gravity well means that it's not really "on the way" to anywhere else, delta-V wise. And, we don't need a million people there if the goal is just to supply fuel to stuff in orbit.
I (and I suspect many others) have a decent idea of the *concept* of quantum computers, but understanding actual application is... elusive.
Just FYI, D-Wave is not a general-purpose quantum computer. It's a specialized device for solving one very specific class of problems; gaining insight into it probably won't help you understand the full capabilities of quantum computers.
I can't explain quantum computers to you in general, because I don't understand them either. I do know one very important application though: using Shor's factorization algorithm to break RSA encryption. You'll hear about it when real quantum computers reach commercial maturity, because a bunch of Slashdot articles will appear about how everyone is in a panic to rush and replace RSA with something else.:-)
I suspect there may be some trade elements to the plan.
What can be made or mined on Mars that can't be made or mined more cheaply on Earth, or from asteroids? Why would Earth pay exorbitant prices for the same stuff we could get much cheaper somewhere else?
Mars... has the possibility of greater rewards...
Such as... ?
The European explorers and colonists to which you appeal went out in search of: 1) trade routes (because people already lived and prospered in the places they were going), 2) precious metals (because mining and transporting them back to Europe cost less than the metals were worth), 3) farm land (because like most everywhere else on Earth Australia had some arable land, some water, some plants already growing there, and plenty of air to breathe),
etc.
It was obvious even at the time how a person might survive - or maybe even get rich - by going to Australia or the Americas. What's the equivalent for Mars?
If I tell you that, from an economic standpoint, colonizing empty space (i.e., the Lagrange points) makes no sense because there are no resources there, does that mean I lack "optimism"? If I tell you that, from an engineering standpoint, colonizing the surface of the Sun is infeasible with current technology, does that mean I'm resistant to "change"? What if I simply direct my "optimism" toward some other "change" that doesn't involve Mars?
They are not planning to take weeks to fuel the spaceship. The plan is to do it in a matter of hours.
Really? For all three to five tanker trips?
Regardless, the typical colony ship is still going to spend a while waiting in orbit given that Musk said that fleets of 200+ ships will gather in orbit and then leave all at the same time. It wouldn't make any sense to try to do 1000+ launches in a matter of hours; it would need so many launch pads which would probably just sit idle most of the rest of the time.
But getting people back to Earth is not really a problem; the spaceship is going to land on Mars, refuel there, and go back to Earth anyway. So the question is only if it is coming back empty or with regretful colonists.
Orbital mechanics and the need to produce new propellants on Mars first suggest that the return trip is a year or two later. That's a long time to deal with a troublemaker in dangerous space colony conditions. It's probably still better to just send them home before leaving, if possible.
Space is big and really empty. There's plenty of room to spread out enough that collateral damage from explosions is not a concern, even if they all leave for Mars on the same day.
Going at the same time improves safety by giving a ship that experiences a serious, but not immediately fatal, system failure the option of evacuating its passengers to other ships in the fleet. They would probably keep their distance from each other unless that actually happened, though.
I know this is Slashdot, where no one even reads the linked article(s), but... would it kill people to do a little research before mocking? If you're going to mock, at least mock a claim that they actually made.
The ships - if they ever get built at all - will not cost billions of dollars each. SpaceX believes they can get the unit cost for each stage down to around $200 million. It also intends to reuse all three stages many times: ~10 for the colony ship, ~100 for the refueling tanker, and ~1000 for the booster.
But as an integrated system, it's a simple fact that the Apollo program produced the most powerful launch vehicle ever created.
You have a very narrow view of aerospace if you think its most important product is launch vehicles, or that the only design goal worth mentioning is raw power. The most important part of the "integrated system" is the payload, not the launch vehicle.
The payload is the part that actually does something useful in its own right: relaying communications, taking pictures, etc. Launch vehicles exist only to help the payload get where it needs to be; unless its actually needed to get the job done, a big launcher is just a waste of resources that could have been spent on a better payload - or even doing something more useful on Earth.
Currently the main economically viable space applications are communications relays and remote observation. Neither of these requires 100 ton satellites/probes, which is why building 100 ton launchers hasn't been a priority.
Modern space communications systems are literally about a million times faster for the same mass. Modern imaging systems, RADARs, high precision clocks (for GPS), etc. are also much better than 1960s stuff.
If we're so much more advanced, why haven't costs come down?...until SpaceX and now Blue Origin came along.
That's a false premise: costs did come down. Even the Delta IV heavy - widely regarded as badly overpriced compared to its contemporaries - is about 30% cheaper to launch on a per-ton basis than the Saturn V ever was. (Don't trivialize that 30% - imagine what a difference it would make in your life if your rent was reduced by 30%. Gains don't have to be exponential Moore's Law-style to be meaningful.)
As for SpaceX... what they've done is quite amazing.
Their internal technical capabilities aren't as far ahead of their competitors as the external results make it appear though: they're "standing on the shoulders of giants". NASA developed the the FASTRAC engine and the PICA heat shield in the late 1990s. 3D metal printing and carbon fibre composite manufacturing were approaching maturity around this time, as well.
SpaceX was founded in 2002 and quickly adopted - and further developed - these cutting-edge technologies which originated with NASA, the established aerospace industry, the university system, etc. They didn't create them, but they had the ambition and the guts to adopt them more quickly than the traditional aerospace industry would otherwise have done. So, they didn't fundamentally put the industry on a different path in that respect - but they did majorly speed things up.
Why haven't capabilities increased?
Where SpaceX and Blue Origin do appear to fundamentally differ from the old guard, is in their belief it's time now to seriously invest in manned space colonization. That's why they're planning monstrously large launchers like the ITS. Manned vessels, unlike computerized satellites/probes, need to be much larger than anything launched today in order to be effective and efficient.
The problem with that, is that currently the technology does not exist to build a self-sustaining colony anywhere but on Earth, even with cheap space launch. SpaceX has already basically said that they're not really working on that side of the problem. So, they're making a huge gamble by assuming that someone else will do it for them. It's very possible that it will all just fizzle out like the Apollo Program did.
That depends entirely on the level of disciple present in the colony.
While discipline can make a big difference, it's not a panacea. Some people will pull themselves together in response to the encouragement and/or threats of a good leader, but others won't.
Even if they behave somewhat better on the outside out of fear of punishment, a person who is depressed, angry at their situation, or locked in a state of panic will still be less productive, less rational, and harder to get along with. Moreover, space-sickness (micro-gravity induced nausea) is a medical condition which no amount of "discipline" can solve if the person's body does not acclimate.
Of course, actually following through on the threats is always an option - but starving troublemakers to death and then shoving them out an airlock is not going to be good for crew morale, and SpaceX may have a really hard time maintaining the support of the government and the public on Earth if news of such measures gets out.
The summary is bad. Each trip is 200+ ships, not just one. The ships are supposed to gather in big fleets in orbit waiting for an optimal transfer window, and then all leave at once for reasons of orbital mechanics and safety.
Doing some maths... sending 200 people per trip, and 50 trips, means 10k people sent there. Assuming half are women, and each woman has 5 children...
It's a bad summary; there is no breeding required to make the numbers work. I watched Musk's talk, and it's really 50 fleets not 50 ships. Groups of about 200 ships will leave at about the same time for reasons of orbital mechanics and safety.
[50 fleets] * [200 ships per fleet] * [100 people per ship] = [1 million people]
Either way, the larger problem is figuring out how to move enough equipment and supplies to keep the colonists alive; it's doubtful that even one million people is anywhere close to enough to produce a self-sustaining ultra-high-tech society in a super-hostile environment as Musk envisions.
The problem is that people are squishy and don't stay perfectly still, so you have to constantly make small course corrections.
That is nonsense. By the law of conservation of momentum, people moving around inside the ship cannot meaningfully alter the course of the ship as a whole during free-fall. During engine burns, the minute shifts in the vessel's centre of mass caused by people's movements will be easily compensated for by the powerful engines - especially since those people will probably be strapped into seats for safety reasons, anyway.
Then there is the aerobraking! At sea level Mars has 0.6% the pressure of Earth. This is why they crash probes into Mars instead of trying to land them. Parachutes won't work...
While Mars' atmosphere is indeed too thin to actually land using only parachutes, it is plenty thick enough for aerobraking to be useful. A significant amount of rocket fuel will be required to stop at the end, but much less than would be required if there were no atmosphere at all.
Just putting a manned spaceship into orbit of Mars would probably take more fuel than landing.... The gravity means that your window of angle of entry is that much smaller where Mars will actually capture you into orbit.
The ship is designed to aerobrake into orbit, and won't use much fuel in the process. Landing will require much more. This is because atmospheric drag scales (to first order) as the square of airspeed. Thus, even a very thin atmosphere can provide tons of drag at interplanetary (hypersonic) speeds, though it will offer almost none during the final phase of landing as the airspeed falls toward zero.
That was arguably the pinnacle of manned space capability and we still haven't matched it with modern systems.
Space technology has advanced steadily since the Apollo era. The reason we haven't done anything as exciting as landing men on the Moon since then is simply because no one wants to pay for it. And why should they? It's billions of dollars spent travelling to places for no better reason, ultimately, than, "Because it's there."
(Colonization doesn't count until it can be convincingly argued that the colonies could eventually become truly self-sustaining, or export something of comparable value to the cost of supporting them with supplies from Earth. We're not there yet; various relevant tech needs to be better developed and demonstrated on Earth before it makes sense to ship it to Mars.)
The modern aerospace industry is far more capable than that of the Apollo era - it just lacks an economic incentive to demonstrate that clearly to the general public. Hopefully Musk has a real business plan.
I'm surprised no one else noticed or commented yet on the final images.
That's because it's just a CGI render, with no indication that SpaceX has any idea how to actually do such a thing from a technical perspective.
Lots of people have speculated (and drawn pretty pictures) about terraforming Mars. However, serious scientific studies of the problem invariably show that it would be astronomically expensive (as in, beyond the combined capabilities of the entire Earth economy), take hundreds to thousands of years, and/or require fantastic technology that does not yet exist.
I saw nothing in the video or the press conference to indicate that SpaceX has come up with a better plan; therefore I interpret the end of the video as a vague hope for the future: something which the proposed Martian colony may eventually achieve on their own, many generations from now.
if you rely on your rocket engines entirely to decelerate (as the video clearly shows), you would need roughly double the fuel
No, it can be done with much less than double the fuel. The trick is that the boost-back and landing burns take place after the second stage and payload have separated from the booster. Thus, because the booster is much lighter on the way down than it was on the way up, it can decelerate itself with relatively little fuel. (On a two-stage rocket, the empty first stage typically weighs significantly less than the fully-fuelled second stage and payload.)
SpaceX has already demonstrated this experimentally with the Falcon 9: the payload penalty to orbit for reusing the first stage is only about 30%.
rely on parachutes and air resistance
The ITS surely takes advantage of air resistance to some extent. Having said that, while aerodynamic drag is an excellent way to decelerate small things, it becomes progressively less effective for larger objects due to the fascinating square-cube law.
Air resistance scales linearly with the object's surface area, while the required deceleration force scales linearly with the object's mass. Surface area scales as the square of the object's linear dimension, while mass scales as the cube of the object's linear dimension. Thus, the mass grows faster than the air resistance.
This is why an ant or a cockroach will land completely unharmed even if dropped from the top of the tallest building in the world, whereas a much larger human would die instantly on impact. It's also why small meteorites tend to burn up very high in the atmosphere, whereas large ones may retain enough speed and mass all the way to the ground to make a crater.
yep, all the fire on the bottom of the shuttle, or a mercury capsule means that air resistance is actually slowing the spacecraft down
The ITS first stage dwarfs the Mercury capsules. Even so, the Mercury capsules had to land in the ocean because their parachutes couldn't slow them down enough to land softly on land. That's very bad for reusability, because sea water is corrosive.
The Space Shuttle Orbiter is much closer in size, but still only massed maybe 1/3rd as much. While it was able to slow itself via aerodynamic forces alone, giving that capability to such a large vessel was extremely expensive in a variety of ways. I won't side-track this post with a full explanation right now, but suffice it to say that the decision to make the Orbiter a giant winged vehicle was a major contributor to all fourteen crew deaths, and to the massive cost overruns.
(There is a reason that neither NASA nor anyone else wants to build a new Space Shuttle - it was a failed design. Dream Chaser may look superficially similar, but it is much smaller and thereby avoids many problems.)
For the ITS, specifically, a winged setup would have the additional problem that it could not return the booster directly to the launch site. Instead it would have to land on an extremely large runway somewhere down-range. Both the launch site and the landing site would need to be on the coast, since the booster is far too big to travel any other way, than by ship.
And yes, I learned this playing Kerbal Space Program
Kerbal Space Program is great. You have to really work at it to accurately model a system like this though - you need to use all the realism mods, build the system at full size, and use a competent auto-pilot for the landing burn. (Manual landings are difficult and waste a lot of fuel compared to a computerized "suicide burn".)
Do it right, and you'll find that Elon's scheme actually works pretty well.
Actually, it's quite possible that the mass of the fuel that would be lost to boil-off is greater than the mass of extra life support required to keep the crew alive a couple of extra weeks.
As for making people wait - normally people's time is considered extremely valuable, but in this case we're talking about people who voluntarily signed up to move permanently to an isolated, barren, frozen, airless wasteland covered in abrasive, (mildly?) poisonous dust. Anyone who does so would probably rather spend the time waiting in "SPAAACCCCCEEEEE!" than on Earth, anyway.
(Or at least they think they would... perhaps sending the people up first is an opportunity to find out who's going to get cold feet before it becomes economically infeasible to bring them home? Sending up a reusable Dragon capsule to collect a few such people from LEO at the last minute is surely cheaper than dealing with the all of the horrible problems that unwilling, depressed, panicky, or constantly space-sick colonists would tend to cause.)
I think it is ***very difficult*** to get out of earth orbit, I'm no expert...
Leaving Earth orbit is actually considerably easier than getting to GEO. It takes slightly less delta-V and does not require any engine restarts or storable propellants.
Successfully navigating to a precise destination (like another planet) is harder, and slowing down to enter orbit or land once you get there is harder still. Nevertheless, there are multiple private companies out there who know how to do it, and the budget required for a small probe is not more than they are used to spending on large GEO satellites.
And then there is the phrase, "once you're in orbit, you're halfway to anywhere." Yeah right but I sure don't see much of anything that went beyond GEO, except for a very small number of spacecraft (all guvmint expenditures) compared to LEO/GEO.
The real reason you don't see non-government missions beyond GEO is that the only space applications which currently actually make money are communications relays and Earth observation. The ideal location for those activities is Earth orbit, so there is no business reason to go further, unless the government is paying you to.
In the near term, the only plausible business opportunity that might bring substantial, reliable private funding to beyond-Earth-orbit activities is asteroid mining. That probably still couldn't make money today, but if the concentration of platinum group metals is really as high as some claim, it wouldn't take too much technological advancement to push it over the edge into profitability.
Then need to deal with radiation, consumables, and be able to fix things when they break (no Progress or Soyuz that can quickly respond).
For unmanned satellites, these kinds of problems are not much worse in interplanetary space than they are in GEO. However, they become severe for humans even in LEO (the ISS project has been insanely expensive), and only get worse the further from Earth you go. Manned colonization cannot be anything but a giant money pit with current technology.
The polls disagree with you. Since the incident where she was dragged away into her getaway van, her numbers dropped and Trump's went up.
I said, "if it were to become known that Hillary could not serve". The fact that she had to leave one event early for health reasons does not prove that she is too ill to serve, except in the minds of those who are just looking for an excuse to reach that conclusion. The official story is that she has pneumonia, which is a treatable disease in people who are otherwise reasonably healthy.
If I had to guess, I would say that the dip in her poll numbers is actually a reaction to the fact that her campaign got caught lying to the public about her health, rather than an indicator that people truly think she'll be unable to serve because of this incident.
The real test of my prediction will be how the public reacts if her health forces her to do something much more dramatic, like quit making public appearances, or drop out of the race entirely.
Slashdot Mirror
I get the feeling that you don't understand how numerous, complex, arbitrary, diverse, ambiguous, etc. natural languages are. That phrase, "all languages", doesn't even have a knowable, well-defined meaning, either in theory or in practice.
It would certainly be possible to improve upon Unicode, if you're willing to sacrifice backwards compatibility. However, it will never achieve your stated goal of guaranteeing support for "all languages" just by "throwing in" a new text processing library.
Projects that refuse to invest in internationalization will continue to fail badly at it, regardless of whether they use Unicode, or a "lessons learned" successor encoding.
On many systems, e.g. Windows, w_char is defined as 16 bits, meaning it can only ever support the Unicode Basic Multilingual Plane without hacks.
True UTF-16 supports non-BMP code points just fine, and is not a "hack". In fact, it's actually slightly easier to do so in UTF-16 than with UTF-8 (the only other common Unicode encoding).
The real problem is that there is no single concept in Unicode that maps to the "character" of the old, simple ASCII standard with which most programmers are familiar. Depending on the task at hand, the correct substitute under Unicode may be code units, code points, or graphemes. Ignorant and/or lazy programmers who make incorrect selections between those three are the cause of many Unicode-related bugs.
Also, some important "Unicode" APIs were stabilized before the standard evolved into its present complex form, and cannot be completely fixed for backwards compatibility reasons: notably, the Java standard library and the Win32 API.
These problems persist for the same reason that commercial software usually doesn't even try to support Linux: the additional market share (in dollars , not just users) which can be captured is perceived to be worth less than the cost of properly writing, optimizing, and testing the considerably more complex and slower code required for full Unicode support.
No. Nor would I be stupid enough to assume the price would drop just because the supply increases (processing cost may not drop).
Earth's surface has far, far more deuterium than anyone is interested in buying at current prices, so there is no reason to export deuterium from Mars at all, unless it can be extracted more cheaply there than here.
Do you have any evidence to support your claim that the price is based soley on demand?
I made no such claim. I said the opposite: that demand is low because the price is high.
Evidence for the absurd assertion that the cost would drop to the same a silver if the supply increased by a factor five?
Again, I made no such claim. What I said is that Martian deuterium could be up to five times cheaper to extract because the concentration of deuterium in Martian water is about five times higher than it is on Earth.
Patently and demonstrably you did not ask for a business case
I did exactly that earlier in this thread: #52979631. That's the whole topic of our discussion: how does a Martian colony pay for itself?
Read the source I provided instead of relying of what you skim-read from someone else's outdated opinion.
In order to support your claim (that a Martian colony can make money by selling deuterium to Earth that was produced as a mere by-product of drinking water extraction), you would need to present evidence that a method of enriching deuterium to double-digit percentages has been discovered which is similar in price to a single round of ordinary water purification by reverse osmosis or distillation. Otherwise, the deuterium extraction would cost significant additional resources just like I said, and not qualify as a mere by-product of drinking water extraction.
The abstract of the paper you linked contains no such evidence (neither the system's costs nor the % enrichment of deuterium achieved is described), and I'm not going to read the full paper because it's pay-walled and I'm not spending $40 to settle a Slashdot debate.
Present technology - with which I'm familiar (and not just from reading /.) is too slow for human transport - but viable for unmanned (or short manned) transport.
I've already stated that I believe the cheapest way to mine asteroids would be largely automated. Economically speaking, it makes no sense to send a million people out there "just because"; machines can do the job cheaper, with perhaps a much smaller number of humans overseeing things.
[sigh]Musk's transports are resusable - what are you wrapping your (imaginary) rockets in? Unicorn farts?
Do you think Musk invented the concept of reuse, or that reuse only works if you're on your way to Mars?
Robotic asteroid mining can be done with reusable launchers (perhaps even the ITS itself), transit stages, etc. more easily than manned colonization can. Asteroid mining equipment doesn't need to repeatedly survive the extreme temperatures and G-forces of planetary launch and re-entry; most of it just goes up once and then stays in micro-gravity for its full service life. Re-fueling is done in Earth orbit, or at an asteroid station.
We don't remotely mine the Pilbara because it's not signficantly cheaper...
Again, how is it that you don't understand that visiting Pilbara is dirt cheap compared to visiting Mars? Just because sending people to Pilbara is cheaper than building better robots doesn't mean that sending people to Mars (something which has never even been done before!) is cheaper.
[cough] That's not an "alternative" (therefore it cannot be "viable") - it's just the (current) situation.
That's a non sequitor. Just because we're a
And yes, I learned this playing Kerbal Space Program
Kerbal Space Program is great. You have to really work at it to accurately model a system like this though - you need to use all the realism mods, build the system at full size, and use a competent auto-pilot for the landing burn. (Manual landings are difficult and waste a lot of fuel compared to a computerized "suicide burn".)
Someone (not me) has now done this and posted the results on YouTube. Only about ten percent of the first stage's fuel was needed for boost-back and landing.
my original contention was this: "[Apollo] was arguably the pinnacle of manned space capability and we still haven't matched it with modern systems." It's irrefutably true
I think it could be argued that the International Space Station is both more advanced than Apollo, and more relevant to solving the hardest problems associated with colonization: keeping people alive, long-term. Nevertheless, I concede the point as you have narrowly defined it.
but if we looked to airliners which are more comparable, this would be like having intercontinental flights in the 70's, and today we can only fly cross-country, but still have to pay 70% of the original price. Pretty tepid "advancement".
The difference here is that there is a huge market for travelling between continents, because all of them (except Antarctica) are great places to live and work. There is no comparable market for flights to the Moon, because there's not much to do there except enjoy looking around and hope you don't die before it's time to go home.
Judging an industry by how good of a "bridge to nowhere" it maintains is not really fair.
I think this is the classic "if you build it, they will come" scenario...
Perhaps. Musk's transport system has a lot of potential, but I think his impatience (driven by anxiety about his own mortality, I suspect) and laser focus on Mars may damage his cause in the long-term.
If he really wants a self-sustaining, economically independent colony, it would be better to drive the technology forward until that is obviously viable. A colony that is always teetering on the edge of disaster, because it was established prematurely, adds little to the robustness of human civilization, but will still consume tremendous resources during the start-up phase - and maybe indefinitely afterwards, too.
There are plenty of incremental steps that could be pursued to drive R&D and expand the industry, such as near-Earth space tourism (as you suggest), asteroid mining, space-based solar, and small-scale research and exploration colonies that aren't intended to be self-sufficient. All of these things would benefit greatly from a huge reusable rocket like the ITS, without the high probability of catastrophic, deadly, horrendously expensive failure that accompanies a premature large-scale colonization effort.
it's extremely rare on Earth ... $2 Billion is not the limit of demand, it's the limit of supply
Do you have evidence for a large pent-up demand for deuterium that would be released by a price drop of less than five times? (That would take it down to about the price of silver.)
the two would be of value for fueling fusion rockets
That's a technology that does not currently exist, and which might not actually use deuterium or tritium when/if it finally gets going.
less than one tenth of what the USA spends annually on the bullshit War on Drugs
This is an irrelevant point of comparison. I'm asking for a business case; you can claim anything is "economically viable" if you're allowed to just steal something else' budget. That argument doesn't tend to convince the people who actually control such budgets, though.
it's just a by-product of potable water production.
This is a ridiculous statement which suggests that you have no idea how deuterium is actually refined, or why it's so expensive. Deuterium will no more be "just a by-product of potable water production" on Mars than it is on Earth.
The concentration of deuterium on Mars is significantly higher than on Earth, but it's still extremely low in absolute terms. Extracting it on Mars will require dedicated machinery and tons of additional energy, just like on Earth. Yes, the amount of additional energy required will be less - but that will be counterbalanced by the generally greater expense of working in a frozen near-vacuum, surrounded by poisonous dust.
Red Herring alert! Can you point to the source of your claim that this fleet won't be waiting for results from surface probes (and many robotic test trips)?!
Musk already decided that we should send one million people there to build a self-sustaining society, even though he himself admitted that he doesn't have any idea how to make that latter part work economically or technologically. That was half the point of his talk...
So in your alternative plan all space exploration will be using theoretical propulsion that starts from this planet ... environmentally friendly and sustainable
Electric propulsion (various styles of ion engines and plasma engines) is not "theoretical" - it's in use today on space probes and even commercial satellites - unlike the deuterium-based fusion that your plans seem to depend upon. And yes, it is more environmentally friendly and sustainable because it's literally about ten times as fuel efficient as chemical rockets.
There are various good reasons why Musk didn't select electric propulsion for his proposal, but they mostly revolve around his fixation on putting tons of human beings on the surface of Mars. For mining the Main Belt, most of his reasons do not apply.
I guess that'll push up the price aluminium, good plan
??? What does this have to do with anything I said? Electric engines can run on pretty much any elemental propellant (as long as it's not too reactive), including abundant hydrogen, or any of the noble gases. My proposal almost certainly uses less aluminium than Musk's, since it requires less total up-mass and aerospace stuff tends to use a lot of aluminium for structural purposes.
Moving a million to Mars is achievable - moving a billion is not. We don't have the resources for it, and environmental effects would have a severe impact on those that don't go.
OK... what does that have to do with our discussion? Who suggested moving a billion people to Mars? I certainly didn't.
I'm somewhat familiar with large scale mining and I find your remote mining of asteroids "controlled from Earth, intriguing. I wonder why we don't do that now instead of FIFO to humpies in the P
I realize that's probably not a serious question, but just in case...
People moving around inside a vehicle can shift the centre of mass and induce rotation. For a spacecraft in free fall, this has no meaningful effect on its trajectory, as Kepler's laws aren't sensitive to the orientation of such a small object. However, for a car in contact with the road, tilting the vehicle may cause it to veer to one side because of asymmetric changes in traction, or mechanical interference with the steering system.
"commercial maturity" being the key word here...
Yes, that phrase was chosen carefully. ;-)
Deuterium
As far as I can tell, the worldwide deuterium market is currently less than $2 billion per year, whereas Musk's plan proposes to spend at least $10 billion per year on transportation alone - and obviously there would be many other large costs associated with establishing a self-sufficient mining colony.
The advent of commercial fusion power might change this - or it might not. Maybe proton-boron fusion will beat deuterium as a fuel, or maybe next-generation fast fission reactors and/or solar power will win the market instead. Establishing a trillion dollar (low estimate) colony to service a market that might not ever even exist is foolish.
Besides which, Earth is quite capable of refining its own deuterium, anyway. (Yes, I know that the concentration of deuterium is greater on Mars. It's still super low though, and the difference might not even pay for the added transportation costs - let alone all of the other tremendous overhead associated with building and maintaining a million-person Martian colony for this task.)
knowledge ... worth more than anything else
Knowledge of Mars can be acquired through exploration, by sending dozens or hundreds of people instead of a million. Keep the population low enough that Earth can afford to support them long-term, so they can focus on their research and exploration. Colonize later when and if the explorers find resources worth exploiting, or technology advances to the point that self-sufficiency is unambiguously doable.
knowledge about the environment that we won't know until surface probes return results
Why not wait for those results before deciding that we should spend a trillion dollars on settling one million people there?
It's a strawman question (intentional?) that ignores viable access to the asteroids of the Main Belt ... it's not about the end-points, it's the points in-between - many of them inhospitable places. All of it driven by trade ...
It would be cheaper to skip the million-person Mars colony, and just focus on mining asteroids. Most (all?) of the work can be done automated with supervision from Earth. The Martian surface is an expensive distraction at the bottom of a deep gravity well. Refuelling at Mars is probably unnecessary with electric propulsion, but can be accomplished with way less than a million people there if needed.
In the case of Australia colonisation was originally intended as a means of supporting and claiming a trading base
The Martian surface is not a good trading base for any destination but itself. The relatively deep gravity well means that it's not really "on the way" to anywhere else, delta-V wise. And, we don't need a million people there if the goal is just to supply fuel to stuff in orbit.
I (and I suspect many others) have a decent idea of the *concept* of quantum computers, but understanding actual application is... elusive.
Just FYI, D-Wave is not a general-purpose quantum computer. It's a specialized device for solving one very specific class of problems; gaining insight into it probably won't help you understand the full capabilities of quantum computers.
I can't explain quantum computers to you in general, because I don't understand them either. I do know one very important application though: using Shor's factorization algorithm to break RSA encryption. You'll hear about it when real quantum computers reach commercial maturity, because a bunch of Slashdot articles will appear about how everyone is in a panic to rush and replace RSA with something else. :-)
I suspect there may be some trade elements to the plan.
What can be made or mined on Mars that can't be made or mined more cheaply on Earth, or from asteroids? Why would Earth pay exorbitant prices for the same stuff we could get much cheaper somewhere else?
Mars ... has the possibility of greater rewards...
Such as... ?
The European explorers and colonists to which you appeal went out in search of:
1) trade routes (because people already lived and prospered in the places they were going),
2) precious metals (because mining and transporting them back to Europe cost less than the metals were worth),
3) farm land (because like most everywhere else on Earth Australia had some arable land, some water, some plants already growing there, and plenty of air to breathe),
etc.
It was obvious even at the time how a person might survive - or maybe even get rich - by going to Australia or the Americas. What's the equivalent for Mars?
If I tell you that, from an economic standpoint, colonizing empty space (i.e., the Lagrange points) makes no sense because there are no resources there, does that mean I lack "optimism"? If I tell you that, from an engineering standpoint, colonizing the surface of the Sun is infeasible with current technology, does that mean I'm resistant to "change"? What if I simply direct my "optimism" toward some other "change" that doesn't involve Mars?
They are not planning to take weeks to fuel the spaceship. The plan is to do it in a matter of hours.
Really? For all three to five tanker trips?
Regardless, the typical colony ship is still going to spend a while waiting in orbit given that Musk said that fleets of 200+ ships will gather in orbit and then leave all at the same time. It wouldn't make any sense to try to do 1000+ launches in a matter of hours; it would need so many launch pads which would probably just sit idle most of the rest of the time.
But getting people back to Earth is not really a problem; the spaceship is going to land on Mars, refuel there, and go back to Earth anyway. So the question is only if it is coming back empty or with regretful colonists.
Orbital mechanics and the need to produce new propellants on Mars first suggest that the return trip is a year or two later. That's a long time to deal with a troublemaker in dangerous space colony conditions. It's probably still better to just send them home before leaving, if possible.
Space is big and really empty. There's plenty of room to spread out enough that collateral damage from explosions is not a concern, even if they all leave for Mars on the same day.
Going at the same time improves safety by giving a ship that experiences a serious, but not immediately fatal, system failure the option of evacuating its passengers to other ships in the fleet. They would probably keep their distance from each other unless that actually happened, though.
So 200+ ships at billions of dollars each?
I know this is Slashdot, where no one even reads the linked article(s), but... would it kill people to do a little research before mocking? If you're going to mock, at least mock a claim that they actually made.
The ships - if they ever get built at all - will not cost billions of dollars each. SpaceX believes they can get the unit cost for each stage down to around $200 million. It also intends to reuse all three stages many times: ~10 for the colony ship, ~100 for the refueling tanker, and ~1000 for the booster.
But as an integrated system, it's a simple fact that the Apollo program produced the most powerful launch vehicle ever created.
You have a very narrow view of aerospace if you think its most important product is launch vehicles, or that the only design goal worth mentioning is raw power. The most important part of the "integrated system" is the payload, not the launch vehicle.
The payload is the part that actually does something useful in its own right: relaying communications, taking pictures, etc. Launch vehicles exist only to help the payload get where it needs to be; unless its actually needed to get the job done, a big launcher is just a waste of resources that could have been spent on a better payload - or even doing something more useful on Earth.
Currently the main economically viable space applications are communications relays and remote observation. Neither of these requires 100 ton satellites/probes, which is why building 100 ton launchers hasn't been a priority.
Modern space communications systems are literally about a million times faster for the same mass. Modern imaging systems, RADARs, high precision clocks (for GPS), etc. are also much better than 1960s stuff.
If we're so much more advanced, why haven't costs come down? ...until SpaceX and now Blue Origin came along.
That's a false premise: costs did come down. Even the Delta IV heavy - widely regarded as badly overpriced compared to its contemporaries - is about 30% cheaper to launch on a per-ton basis than the Saturn V ever was. (Don't trivialize that 30% - imagine what a difference it would make in your life if your rent was reduced by 30%. Gains don't have to be exponential Moore's Law-style to be meaningful.)
As for SpaceX... what they've done is quite amazing.
Their internal technical capabilities aren't as far ahead of their competitors as the external results make it appear though: they're "standing on the shoulders of giants". NASA developed the the FASTRAC engine and the PICA heat shield in the late 1990s. 3D metal printing and carbon fibre composite manufacturing were approaching maturity around this time, as well.
SpaceX was founded in 2002 and quickly adopted - and further developed - these cutting-edge technologies which originated with NASA, the established aerospace industry, the university system, etc. They didn't create them, but they had the ambition and the guts to adopt them more quickly than the traditional aerospace industry would otherwise have done. So, they didn't fundamentally put the industry on a different path in that respect - but they did majorly speed things up.
Why haven't capabilities increased?
Where SpaceX and Blue Origin do appear to fundamentally differ from the old guard, is in their belief it's time now to seriously invest in manned space colonization. That's why they're planning monstrously large launchers like the ITS. Manned vessels, unlike computerized satellites/probes, need to be much larger than anything launched today in order to be effective and efficient.
The problem with that, is that currently the technology does not exist to build a self-sustaining colony anywhere but on Earth, even with cheap space launch. SpaceX has already basically said that they're not really working on that side of the problem. So, they're making a huge gamble by assuming that someone else will do it for them. It's very possible that it will all just fizzle out like the Apollo Program did.
That depends entirely on the level of disciple present in the colony.
While discipline can make a big difference, it's not a panacea. Some people will pull themselves together in response to the encouragement and/or threats of a good leader, but others won't.
Even if they behave somewhat better on the outside out of fear of punishment, a person who is depressed, angry at their situation, or locked in a state of panic will still be less productive, less rational, and harder to get along with. Moreover, space-sickness (micro-gravity induced nausea) is a medical condition which no amount of "discipline" can solve if the person's body does not acclimate.
Of course, actually following through on the threats is always an option - but starving troublemakers to death and then shoving them out an airlock is not going to be good for crew morale, and SpaceX may have a really hard time maintaining the support of the government and the public on Earth if news of such measures gets out.
20-50 trips * 100-200+ people = 1 000 000?
The summary is bad. Each trip is 200+ ships, not just one. The ships are supposed to gather in big fleets in orbit waiting for an optimal transfer window, and then all leave at once for reasons of orbital mechanics and safety.
Doing some maths... sending 200 people per trip, and 50 trips, means 10k people sent there. Assuming half are women, and each woman has 5 children...
It's a bad summary; there is no breeding required to make the numbers work. I watched Musk's talk, and it's really 50 fleets not 50 ships. Groups of about 200 ships will leave at about the same time for reasons of orbital mechanics and safety.
[50 fleets] * [200 ships per fleet] * [100 people per ship] = [1 million people]
Either way, the larger problem is figuring out how to move enough equipment and supplies to keep the colonists alive; it's doubtful that even one million people is anywhere close to enough to produce a self-sustaining ultra-high-tech society in a super-hostile environment as Musk envisions.
The problem is that people are squishy and don't stay perfectly still, so you have to constantly make small course corrections.
That is nonsense. By the law of conservation of momentum, people moving around inside the ship cannot meaningfully alter the course of the ship as a whole during free-fall. During engine burns, the minute shifts in the vessel's centre of mass caused by people's movements will be easily compensated for by the powerful engines - especially since those people will probably be strapped into seats for safety reasons, anyway.
Then there is the aerobraking! At sea level Mars has 0.6% the pressure of Earth. This is why they crash probes into Mars instead of trying to land them. Parachutes won't work...
While Mars' atmosphere is indeed too thin to actually land using only parachutes, it is plenty thick enough for aerobraking to be useful. A significant amount of rocket fuel will be required to stop at the end, but much less than would be required if there were no atmosphere at all.
Just putting a manned spaceship into orbit of Mars would probably take more fuel than landing. ... The gravity means that your window of angle of entry is that much smaller where Mars will actually capture you into orbit.
The ship is designed to aerobrake into orbit, and won't use much fuel in the process. Landing will require much more. This is because atmospheric drag scales (to first order) as the square of airspeed. Thus, even a very thin atmosphere can provide tons of drag at interplanetary (hypersonic) speeds, though it will offer almost none during the final phase of landing as the airspeed falls toward zero.
That was arguably the pinnacle of manned space capability and we still haven't matched it with modern systems.
Space technology has advanced steadily since the Apollo era. The reason we haven't done anything as exciting as landing men on the Moon since then is simply because no one wants to pay for it. And why should they? It's billions of dollars spent travelling to places for no better reason, ultimately, than, "Because it's there."
(Colonization doesn't count until it can be convincingly argued that the colonies could eventually become truly self-sustaining, or export something of comparable value to the cost of supporting them with supplies from Earth. We're not there yet; various relevant tech needs to be better developed and demonstrated on Earth before it makes sense to ship it to Mars.)
The modern aerospace industry is far more capable than that of the Apollo era - it just lacks an economic incentive to demonstrate that clearly to the general public. Hopefully Musk has a real business plan.
I'm surprised no one else noticed or commented yet on the final images.
That's because it's just a CGI render, with no indication that SpaceX has any idea how to actually do such a thing from a technical perspective.
Lots of people have speculated (and drawn pretty pictures) about terraforming Mars. However, serious scientific studies of the problem invariably show that it would be astronomically expensive (as in, beyond the combined capabilities of the entire Earth economy), take hundreds to thousands of years, and/or require fantastic technology that does not yet exist.
I saw nothing in the video or the press conference to indicate that SpaceX has come up with a better plan; therefore I interpret the end of the video as a vague hope for the future: something which the proposed Martian colony may eventually achieve on their own, many generations from now.
if you rely on your rocket engines entirely to decelerate (as the video clearly shows), you would need roughly double the fuel
No, it can be done with much less than double the fuel. The trick is that the boost-back and landing burns take place after the second stage and payload have separated from the booster. Thus, because the booster is much lighter on the way down than it was on the way up, it can decelerate itself with relatively little fuel. (On a two-stage rocket, the empty first stage typically weighs significantly less than the fully-fuelled second stage and payload.)
SpaceX has already demonstrated this experimentally with the Falcon 9: the payload penalty to orbit for reusing the first stage is only about 30%.
rely on parachutes and air resistance
The ITS surely takes advantage of air resistance to some extent. Having said that, while aerodynamic drag is an excellent way to decelerate small things, it becomes progressively less effective for larger objects due to the fascinating square-cube law.
Air resistance scales linearly with the object's surface area, while the required deceleration force scales linearly with the object's mass. Surface area scales as the square of the object's linear dimension, while mass scales as the cube of the object's linear dimension. Thus, the mass grows faster than the air resistance.
This is why an ant or a cockroach will land completely unharmed even if dropped from the top of the tallest building in the world, whereas a much larger human would die instantly on impact. It's also why small meteorites tend to burn up very high in the atmosphere, whereas large ones may retain enough speed and mass all the way to the ground to make a crater.
yep, all the fire on the bottom of the shuttle, or a mercury capsule means that air resistance is actually slowing the spacecraft down
The ITS first stage dwarfs the Mercury capsules. Even so, the Mercury capsules had to land in the ocean because their parachutes couldn't slow them down enough to land softly on land. That's very bad for reusability, because sea water is corrosive.
The Space Shuttle Orbiter is much closer in size, but still only massed maybe 1/3rd as much. While it was able to slow itself via aerodynamic forces alone, giving that capability to such a large vessel was extremely expensive in a variety of ways. I won't side-track this post with a full explanation right now, but suffice it to say that the decision to make the Orbiter a giant winged vehicle was a major contributor to all fourteen crew deaths, and to the massive cost overruns.
(There is a reason that neither NASA nor anyone else wants to build a new Space Shuttle - it was a failed design. Dream Chaser may look superficially similar, but it is much smaller and thereby avoids many problems.)
For the ITS, specifically, a winged setup would have the additional problem that it could not return the booster directly to the launch site. Instead it would have to land on an extremely large runway somewhere down-range. Both the launch site and the landing site would need to be on the coast, since the booster is far too big to travel any other way, than by ship.
And yes, I learned this playing Kerbal Space Program
Kerbal Space Program is great. You have to really work at it to accurately model a system like this though - you need to use all the realism mods, build the system at full size, and use a competent auto-pilot for the landing burn. (Manual landings are difficult and waste a lot of fuel compared to a computerized "suicide burn".)
Do it right, and you'll find that Elon's scheme actually works pretty well.
No point in keeping people waiting in orbit.
Actually, it's quite possible that the mass of the fuel that would be lost to boil-off is greater than the mass of extra life support required to keep the crew alive a couple of extra weeks.
As for making people wait - normally people's time is considered extremely valuable, but in this case we're talking about people who voluntarily signed up to move permanently to an isolated, barren, frozen, airless wasteland covered in abrasive, (mildly?) poisonous dust. Anyone who does so would probably rather spend the time waiting in "SPAAACCCCCEEEEE!" than on Earth, anyway.
(Or at least they think they would... perhaps sending the people up first is an opportunity to find out who's going to get cold feet before it becomes economically infeasible to bring them home? Sending up a reusable Dragon capsule to collect a few such people from LEO at the last minute is surely cheaper than dealing with the all of the horrible problems that unwilling, depressed, panicky, or constantly space-sick colonists would tend to cause.)
I think it is ***very difficult*** to get out of earth orbit, I'm no expert...
Leaving Earth orbit is actually considerably easier than getting to GEO. It takes slightly less delta-V and does not require any engine restarts or storable propellants.
Successfully navigating to a precise destination (like another planet) is harder, and slowing down to enter orbit or land once you get there is harder still. Nevertheless, there are multiple private companies out there who know how to do it, and the budget required for a small probe is not more than they are used to spending on large GEO satellites.
And then there is the phrase, "once you're in orbit, you're halfway to anywhere." Yeah right but I sure don't see much of anything that went beyond GEO, except for a very small number of spacecraft (all guvmint expenditures) compared to LEO/GEO.
The real reason you don't see non-government missions beyond GEO is that the only space applications which currently actually make money are communications relays and Earth observation. The ideal location for those activities is Earth orbit, so there is no business reason to go further, unless the government is paying you to.
In the near term, the only plausible business opportunity that might bring substantial, reliable private funding to beyond-Earth-orbit activities is asteroid mining. That probably still couldn't make money today, but if the concentration of platinum group metals is really as high as some claim, it wouldn't take too much technological advancement to push it over the edge into profitability.
Then need to deal with radiation, consumables, and be able to fix things when they break (no Progress or Soyuz that can quickly respond).
For unmanned satellites, these kinds of problems are not much worse in interplanetary space than they are in GEO. However, they become severe for humans even in LEO (the ISS project has been insanely expensive), and only get worse the further from Earth you go. Manned colonization cannot be anything but a giant money pit with current technology.
The polls disagree with you. Since the incident where she was dragged away into her getaway van, her numbers dropped and Trump's went up.
I said, "if it were to become known that Hillary could not serve". The fact that she had to leave one event early for health reasons does not prove that she is too ill to serve, except in the minds of those who are just looking for an excuse to reach that conclusion. The official story is that she has pneumonia, which is a treatable disease in people who are otherwise reasonably healthy.
If I had to guess, I would say that the dip in her poll numbers is actually a reaction to the fact that her campaign got caught lying to the public about her health, rather than an indicator that people truly think she'll be unable to serve because of this incident.
The real test of my prediction will be how the public reacts if her health forces her to do something much more dramatic, like quit making public appearances, or drop out of the race entirely.