Nibb31

When the ISS reaches its end of life, it's because it will no longer be safe. They won't shut it down for fun. They shut it down because parts get worn out, seals start leaking, filters get clogged up, solar panels lose power, batteries die, fluids degrade and run low, lubricants wear out, materials degrade, etc... If it's powered-up, it requires maintenance, station-keeping, atmospheric pressure, monitoring, and repairs. If it's powered-down, vented, and abandoned, it can't be restarted and it will eventually leak, break up, and become a hazard as a source of debris. - - - Updated - - - As long as the space tourism market is big enough to keep those multiple providers alive. With 7 people per launch, at the cost of the current vehicles, even heavily subsidized by NASA, I can't see that happening.

- Grey goo doesn't exist. There's no point in paying insurance for threats that don't exist. - Some would be pulverized. Some would survive. You would still save orders of magnitude more lives than a space colony. - Mars will never be more hospitable than a scorched Earth. A half-destroyed Earth will still have some sort of atmosphere that you can filter, water that you can recycle, and more wind and solar power than Mars will ever have. - Mars has less sunlight for solar power. - What useful resources does Mars have that the Earth doesn't? - What's more appealing, living underground on Earth with the hope of coming out one day for some fresh air and rain, or living underground on Mars to protect from the radiation, the cold, and the toxic atmosphere. In the 1960's people were expecting Mars colonies by the late 70's.

Because the perspective of disease, famine, and conflicts was better than the conditions they were living in at home. The same is true for the hordes of migrants who drown crossing the Mediterranean every year. It's an ongoing tragedy. The difference is that the people who are going to afford a ticket to Mars aren't typically the same as those migrants. The Venn diagram of: a) people who can afford to settle on Mars people who are persecuted on Earth, and c) people who have skills that can be useful to for a new colony, doesn't have a really big intersection. In the countries where people could afford to migrate to Mars, you pretty much have your political and religious freedom. Actually, if you have a million dollars to spend on that, then it's likely that you are among the privileged, not the persecuted. And there is no reason to believe that a privately owned colony controlled by Elon Musk or anyone else is going to be a political and religious utopia that would be any better than where you currently live. It's actually likely to have less freedom than on Earth due to rationing and safety concerns and to ask more of its citizens than to just contribute taxes. Colonization was funded by European nations because there were resources and lucrative trade routes and a power struggle for grabbing territories before their opponents. There also weren't any required qualifications. Nations had no trouble finding candidate colonists, because the colonies offered a hope of settling on fertile land or finding resources that would improve their subsistence. The conditions are completely different today. There is no fertile land on Mars. There are no resources that can be traded on Earth. Nothing on Mars will make you wealthier, safer, or more confortable. The soil is poisonous. If you go outside, you die. If you breath the dust, you die. If supplies arrive late, you die. If your power breaks down, you die. If you don't have someone with a specific skillset, you die. It would be like spending the rest of your life inside an air-conditioned trailer feeding on hydroponic lettuce and recycled urine, and never again feeling a breeze of wind in your hair or rain on your face. Why would anyone who has a million dollars on Earth want that kind of life, instead of moving the Bahamas for example? This assumes that: a- An increasing population is inevitable and can't be controlled. Well, nowadays, we have the pill and ...-education, which can make the World a better place for everyone. b- That technology will keep on advancing even though the economy stagnates and the standard of living decreases. If we get to a point where life on Earth is so bad that we need to go elsewhere, scientific progress will probably be stagnating too.

You would just send in ground troops to unplug the enemy's modem. Frag! I don't see virtual wars happening, other than through electronic warfare as part of a real-world conflict. There is however the possibility of seeing "drone vs drone" confrontations fought by proxy with no actual casualties, but the objectives of such attacks would always be to hit real world targets.

No, not unless those satellites were designed with docking rings, hand rails, removable covers, secure edges, safing systems, replaceable parts, and so on. All of that adds to the complexity, weight, and cost of the satellite. In addition, the satellite also needs to be put in an orbit that is accessible to a manned vehicle, but might not be optimal for the mission. HST would have provided better results if it was at a Lagrange point like most other astronomy satellites, but they had to compromise by putting it in LEO so that the Shuttle could reach it. In addition to the cost of the launch, a servicing mission requires that you actually design, build and test those replaceable parts, that you charter and plan a mission, immobilizing expensive astronauts for months of training, and risking their lives on EVA, using manned spaceflight resources that could be used for more valuable tasks than swapping a stupid component. Hubble cost around $2 billion. Each of its 5 servicing missions cost around $1 billion. For the cost of the whole program, you could have launched at least 4 non serviceable HSTs. Give us one single experiment that a manned geology lab could perform that could not be done automatically by a robotic science mission.

Just like the Space Shuttle or Buran, it uses thrust vectoring. Gimball the nozzle and point it so that the thrust vector goes through the actual center of mass. The drawback is that you lose a bit of efficiency through cosine losses.

Really TL:DR; Especially as it's mostly (longwindedly written) stuff that we've already discussed at length on these forums. But I pretty much agree with what Ralathon said.

What makes you think that living in space is freedom? If anything, you spend the rest of your life stuck inside a tin can, hoping that the thin wall that keeps you alive doesn't corrode or get punctured. The problem with the planet getting crowded won't be solved by sending a few thousand people into space. In fact, consuming the ressources to accelerate all those people from 0 to 26000km/h will only make things worse. And no, people don't typically migrate to places that are life-threateningly dangerous. A minority of people like to explore extreme places because of the thrill that it gives them, but that's a minority, and it's usually for short visits. Most humans only usually migrate to places that are likely to provide safety, comfort, wealth, and a better life for their children. Space is none of that. - - - Updated - - - Probably not, but if we detected an ELE (which isn't very likely because the Earth has pretty much cleared its orbit and we have a pretty good count of the biggest asteroids in the solar system), there are much easier ways of dealing with it than to colonize other planets. The most likely today would probably be to brace for the impact. In the future, we might be able to deflect it. Generalizing a certain trait to all mankind is a bit of a leap. Some cultures admire explorers, adventurers and thrill seekers. Others not so much. It's more of a cultural trait than a universal trend. Negative population growth is pretty much the only way for us to survive at this point. It's much more that crossing our fingers and hoping that someone invents an interstellar warp drive soon. - - - Updated - - - Derogatory remarks about Africa notwithstanding, colonizing the solar system in advance with the motivation of preserving the human genome from an asteroid impact on Earth would take decades of preparation, whatever the country that initiates it. If that is your motivation, and you are willing to spend resources to prepare for such an event, then it's much easier to just build and maintain underground vaults in advance or to design a deflection strategy in advance. Both strategies would save orders of magnitude more lives than a colony on Mars. Because as an individual, I enjoy being alive. That's a good enough reason I think. - - - Updated - - - Hubble was worth repairing because it was super-expensive. It was super-expensive because it was designed to be repairable. It was designed to be repairable because NASA needed to give the Shuttle something to do. The whole program proved one thing: it would have been safer, cheaper, and more efficient, to launch a series of redundant disposable telescopes on EELVs. Which is basically what the NRO did with their own version of Hubble (KH-11).

Even after being hit by a life ender, the Earth would still be more hospitable than Mars or the Moon. Of course, anything is possible... but what are the chances of that happening over the next few thousand years? At our current tech level, we could probably survive any of the asteroid impacts that have hit the Earth in the past. If we were really interested in preserving the human species, we could build hundreds of pre-equipped underground vaults around the world for a fraction of the cost of colonizing Mars. If only a couple of them make it through the impact, then the species will be ok. Also if we had the technology to send thousand of colonists to Mars, we would also have the technology to deflect an asteroid. My point is that if we fail to survive, it will be no big deal, because there will be nobody around to feel bad about it. It might make you sad to anticipate the sadness of not existing anymore, but that's just silly, because nobody will feel sad about it afterwards. It's best to just enjoy the life that we have and make the most of it, rather than to lament about something that nobody will ever experience. Well, I guess that's the philosophical idea of having a destiny. I don't think that there is such thing. I think we are simply organisms that have evolved to fill a niche in a specific environment. If the environment changes or if that niche is no longer available to us, we will either go extinct or adapt. If we go extinct, then life will undoubtedly find a way and something else will fill that niche. Either way, we will no longer be the species known as "homo sapiens", so it doesn't really matter in the long run.

Because most humans are self-centered and don't step back to look at the big picture. Everything is relative. I enjoy following human spaceflight as much as anyone else here. It's inspiring, and entertaining, but then so are movies, books, sports, or TV shows... Personally, I'm quite happy to see my government money being spent on space for my personal entertainment (much more than to see similar amounts spent on stadiums sport infrastructure for example), but it's hard to justify it at a political level, which is where the spending decisions are made.

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First of all, there isn't anything that would totally exterminate the human species. Even if a killer asteroid wiped off 99.99% of the population, you will still have a bottleneck population of a few million inhabitants somewhere on the planet, which is more than we were a mere 500 years ago. Even a few thousand survivors would be more than you will ever have in a space colony before a very very long time. Secondly, even if we became capable of building self-sufficient habitats on Mars or the Moon that could survive without constant supplies from Earth, we would also be capable of building the same self-sufficient habitats on a scorched Earth. Survival on a dilapidated Earth will always be easier for us than survival on another planet. We are highly adaptable and capable of surviving pretty much anything in large enough numbers that our genome isn't at risk. Finally, even if we are exterminated, it's no big deal in the grand scheme of the universe. The human species isn't any more valuable than the other thousands of species that disappear every year. We are an insignificant drop in the ocean of life on this planet, which itself is an insignificant spec of dust in the universe. It's not like there will be anyone around to complain that we are all gone. Nobody is going to judge us or to give us brownie-points for achievements. Nothing lives forever, and we will not escape going extinct or evolving into something else at some point, just like every other living organism. Preserving the "human species" makes no sense when we are constantly evolving. In a few thousand years, we will probably have evolved socially and biologically enough for you to not even recognize us as human any more if you were to come back. Even more so if those humans need to adapt to a off-world environment. Our descendants living in underground habitations on Mars in 100,000 years wouldn't be the same "human species" that you wanted to preserve in the first place.

Debunked long ago.

If altitude was important, something like the Stratolaunch carrier plane would be much cheaper (and more flexible) than a fixed 20km tower. But even Stratolaunch doesn't make any sense.

You are absolutely right. If the the program is in trouble, it is because of the shortsightedness of Congress. But that doesn't change the fact that it's in trouble. The current end of the ISS program is 2024 (possibly 2028). From 2018 to 2024, that is 6 years and basically 12 flights shared between 2 vehicles, or one flight per year for each vehicle. The commercial crew program pays for 6 Dragons and 6 CST-100s, and that's it. That is a whole lot of overhead and infrastructure to set up for such a small number of launches. It's obvious that it would be much cheaper to have a single supplier. And for only 12 flights, it would probably be cheaper to just pay the Russians and be done with it. Of course, that reasoning ignores the real point of the program, which is to provide government subsidies to the aerospace industry in order to maintain America's technological capability of manned spaceflight. Whether that money goes to Boeing or SpaceX is irrelevant as long as it stays in the country. Giving it to Boeing actually probably funds more jobs than SpaceX, and Boeing has a stronger influence in Washington because it funds more political campaigns.

Launching and landing from an altitude of 20km does nothing to reduce propellant requirements. To reach orbit, you still need to accelerate from 0 to 26000 km/h, which is still going to take the same amount of energy, minus some drag. On the diagram, their platform has a runway for winged vehicles. What's the point of landing a winged vehicle if you are supposed to be trying to benefit from not having drag? Reducing drag also means reducing lift, and therefore reducing the reason for having wings.

It means going from funding 2 providers (SpaceX and Boeing) to 1 (Boeing). SpaceX actually isn't the "obvious choice". For NASA, Congress, and the administration, Boeing is. SpaceX is an outsider. Delaying commercial crew is indeed the worse choice because it's already a ridiculously low volume with only a dozen flights over a couple of years before the ISS is retired. That's 6 flights for each vehicle, less than Gemini or even Vostok. It already doesn't really make much sense to fund two vehicles for that. It makes even less sense if you reduce the number of flights.

The only justification for sending humans into space is to study how to send humans into space, which is circular reasoning. Any other rational goal, such as science or exploration, can be done much more efficiently through telepresence. And the irrational goals, such as "inspiration" or "prestige" are just excuses for a certain entertainment value for a minority of geeks. I love the inspiration and the prestige just as much as everyone here, but I struggle to find a justification for the cost and risk of it all. I really wish we could. The Hubble servicing missions were justified by the fact that it was designed to be serviced by the Shuttle. Another circular justification. The high cost of Hubble was mostly due to the extra complexity of designing it to be serviceable in space. If they had made Hubble non-serviceable, it would have been much cheaper to just launch a few new ones instead of fixing it.

You need to make a bootable windows 10 USB drive. But you shouldn't need to do a clean install. What problems are you having? The only problems that I've seen people have are related to video drivers. Just reinstall the drivers and you should be ok.

There is no way they can keep that schedule, even if you doubled the current budget. There simply aren't enough payloads to fly one SLS per year. The Europa Flyby mission won't be ready before EM-2, neither will ARM (if it goes through), and the L2 space station is pie in the sky. If you want to fly one mission per year on SLS around 2020-2025, those missions should already be cutting metal. Yes, the only hope for SLS is for the next US administration to give a clear and funded roadmap for it. Unfortunately, space is way down on the list of priorities for presidential platforms, so don't get your hopes up too high.

It means your program crashed.

Not only is it unlikely that a message ever reaches our solar system, but the universe is 13 billion years old and we have only been listening to radio signals for less than 100 years. The chances of an alien species broadcasting a message that coincides with this tiny moment in time is infinitesimal. It is actually millions of times more unlikely that winning the lottery or finding a needle in a haystack.

There hasn't been any news about the Zero Emission Hyper Sonic Transport for years. It was probably just a low-budget trade study with no real intentions to go any further.

It's a totally stupid situation brought down by totally stupid politicians. They want their SLS so bad that they are ready to sacrifice even Commercial Crew to get it. They really want to use Orion for ISS ops, which reaches another level of stupid. I hope the upcoming elections give them a kick in the head and that the new POTUS, whoever it is, finally gives a real direction to NASA. For the poll, I have no doubt that the fanbois here will massively want to downselect to SpaceX and cut CST-100 for the sole reason that it looks so old-school. The reason the downselect would be in Boeing's favor is because it will be ready sooner and carries less risk.

At the cost of how many unmanned missions with the same science capability? Don't forget that the astronauts will only be doing effective work for a fraction of that time. Out of an 18 month mission duration, they will spend 6 months asleep, 2 months eating and 4 months doing maintenance work just to stay alive. An unmanned rover can hang around for maybe 10 years. For the same price as a manned mission, you could send a swarm of unmanned rovers to cover pretty much every spot of interest on the planet. No more landing site dilemmas. There simply is nothing that a manned mission can do that an equivalent unmanned science mission can't do for a fraction of the cost and risk. By the time we get to the point where we can send a manned expedition, around the 2030's, unmanned rovers will only have even more advanced AI and higher mobility, which will reduce the gap even more. In fact, the only scientific reason to send humans to Mars is to study how to send humans to Mars. Circular arguments are hard to justify. Absolutely. Now all you need is to put a price tag on that inspiration value. How much are the taxpayers willing to pay for "inspiration"? Try asking real people around you, not just the space geek crowd. To get things done, you need a measurable return on investment. In the 60's, NASA's goal was to kick the Soviet's ass in the context of the Cold War. Demonstrating the supremacy of the USA over communism was the return on investment, not "inspiration" or some other fuzzy concept, and politicians were willing to give NASA an unlimited budget to do it. If your goal is simply "inspiration" (whatever that means) then there are much cheaper ways than to spend $100 billion on a Mars mission. Nowadays, NASA's mission has shifted, and the only rational motive for space exploration is science. And the best return on investment for science is to send unmanned missions. You might not like it, but there's no dodging the cruel reality of today. That's what NASA is trying to do. Just look at the comments on their Google+ feed or Youtube channel and you will see that they are fighting an uphill battle there.