Nibb31

I'd like an interstellar warp drive module, a Star Trek transporter, and a space brewery. Sorry, but I find discussions about real possibilities more interesting than conjecture about things that have zero chance of happening.

Nice ideas in an ideal world, but where's the money going to come from? #1 costs too much. #2 is done on the Russian segment. Progress and ATV refuel the Zvezda service module. #3 is too dangerous. Remember that anything in LEO reenters one day and things can go wrong. #4 is already done in the various experiments on board. #5 isn't possible. Giant lasers can burn holes, but they can't "annihilate". Also, the ISS has been extended to 2024. There isn't enough time left in the ISS program to design and launch new modules.

Huh? .

It would pretty much hit the ground at terminal velocity, which would depend on the mass and drag of the rod. I would imagine that deorbiting it would be inefficient because you would actually need to reduce the energy that you imparted into the object by sending it to orbit. Wouldn't it be better to accelerate your projectile into a high apogee/high energy parabolic trajectory, so that it reenters on a near-vertical trajectory with even more energy? Of course, in that case you lose the "rapid response" capability of the weapon, which wasn't great anyway... and there wouldn't be much point in launching it from orbit in the first place, as it would basically just be an ICBM with a telephone pole on top.

I agree... It's not the first mod to never be released because it was getting overly ambitious. Most of us would have been happy with a first release without any IVA (I suspect that most of us never use IVA anyway).

It's not something that can be monetized to recoup the hundreds of billions of dollars that you invested to pull it off though.

Cheap access to space is never going to happen in the next 20 or 30 years anyway. The energy requirements to get a given mass into orbit are huge, and the engineering requirements to contain that energy within a given mass are always going to be expensive. Do you think that a nuclear drive would be cheap? Fissile material is expensive to process and to handle, and hopefully it will remain that way. But political problems are no less real. It would be impossible to cancel the nuclear test ban treaties, because that would allow Iran, Pakistan, or North Korea to irradiate half of the planet "for peaceful research purposes". The whole idea of allowing atmospheric nuclear tests to resume would be met by the opposition of 99% of the World's population. Heck, even the wackiest contributors of this forum disagree with you on that! You can spit and rant as much as you want, you won't change the fact that it's politically unworkable. It's dead Jim. You need to get over it. It's not gonna happen. So because launch costs are prohibitive, you suggest building a fleet of $500 billion dollar space ships that run on Deuterium ? Yes, you are turning in circles, repeating the same arguments, that we keep on debunking again and again. In another thread I gave you some other great examples of things that people thought were good ideas in the 50's. They also thought that the Ford Nucleon would be economical (a full tank of plutonium lasts the life of the car!) or that strip mining with nukes would be harmless and profitable. Heck, in the 70's, even the Space Shuttle seemed like a good idea! No way would nuclear bombs turn out that cheap and easy to handle. If they were, some dictator would have blown Humanity to smithereens decades before an Orion spaceship could fly. Simply decontaminating the launch area to prepare for another launch would cost billions. Let alone the processing and handling of the bombs, the extra security, the ship itself... Just about everything in Orion would cost hundreds of billions of dollars that nobody is willing to pay for because there is no ROI in space for such an investment and no economical purpose for such a huge upmass. Yes, it's that annoying economic reality again.

Reality strikes again: - It's not possible to test it in the atmosphere because atmospheric nuclear tests are banned since 1963. - It's not possible to test it in space because nuclear tests in space are also banned since 1967. - It's not possible to test it underground because nuclear tests underground are also banned since 1996. - It's not practical to test it in orbit because there are too many risks of damaging LEO/GEO satellites and it would leave clouds of radioactive particles and debris that could be a hazard for future missions. - It's not practical to test it on escape trajectories, because it would simply be too expensive for the sort of subscale proof-of-concept testing that is required. - It's not practical to test it anywhere because the negative political impact would put too much pressure on the administration. There are reasons Orion was cancelled. It is simply not a viable project for the foreseeable future, for many many reasons. Forget it.

100 tons underneath a parachute? There are practical limits to the size of a parachute in real-life. What's the source for that picture?

Not very realistic, is it? What's the economical motive for bringing back an empty payload bay if it comes back empty? And it pretty much exceeds the practical limits of modern parachutes, especially if you wanted to bring back a full-size payload. You would be better off with a soyuz capsule for the crew and a disposable payload fairing underneath it.

Yes, but as I said earlier, our actual policy and economy may be inefficient, but that is the environment that we have to work with for the foreseeable future. All systems have their inefficiencies, and it's simply not realistic to believe that we will suddenly overcome those inefficiencies in the next 20 or 30 years. In the real world, the political and economical constraints exist and are just as real as the laws of physics. They can't just be handwaved away.

You should take a closer look at Buran. The similarities with the US STS are only superficial. The main difference was that Buran's main engines were on the Energia launcher and were expendable. This has a huge impact on the economics and even the sheer point of reusing the orbiter vehicle. The whole point of the reusing the orbiter was to bring back the engines for reuse. If you're dumping the most expensive part of the vehicle, then there is no need to bother with all the extra spaceplane bits and just bring the crew back in a capsule. The concept didn't make sense, even to the Russians, who weren't stupid. But in the 70's-80's, the Soviets were totally paranoid and were fully expecting Nixon or Reagan to initiate a first strike against them. They figured that if the Americans were making a space shuttle, there must have been a military purpose behind it, so they wanted the same capability, even though the actual military purpose didn't make sense.

They usually do the best they can within the requirements and constraints that they are given.

Yeah. It's not really far-fetched to assume that thousands of aerospace engineers and scientists are collectively smarter than you or me, is it? Arrogance much? But they are no less real. But that's how the system works. Trust me, changing the political system and creating a fair society without politicians, where everybody agrees to fund your particular hobby, is going to be much harder than inventing a warp drive. Politics are part of the system, whether you spit on it or not. Nothing exists in a vacuum, and the political and economical environment is just as much a constraint as Newton's laws. You can't just handwave those things away. Yes, we have inefficiencies. We have limited resources. Our system isn't perfect, but it's the one we have to work with. Let's not get into the Orion drive debate again. NTR is probably feasible, but Orion certainly isn't. Do you really still need to be told again why detonating nuclear bombs in the atmosphere is a bad idea? Do you really think it would be practical to have hundreds of people working on a spaceship sitting in the middle of a highly irradiated wasteland? Studies from the 50's are no longer relevant. You would need to redo them with modern physics if you wanted to convince anyone that Orion is a good idea.

It sounded like a good idea at the time, so you can't really blame them. Hindsight and all that...

There is no Mars plan. NASA does all sorts of wacky studies, it's their job and they have a tiny part of their budget dedicated to thinking up paper studies for future missions. Only when Congress votes a budget for a program does it start to exist. Where is the Congress vote for a Mars colony? Absolutely not. I'm as much of a space geek as anybody. I just despise the handwaving from armchair engineers who say "it's easy" because they read an article about the Albucierre drive. Experience shows that doing stuff in space is hard and expensive. That's all. People much smarter than you have been wracking their brains for decades to do this stuff. The technology that we have now is the best stuff that they could do with the real-life constraints they have. If they could do better, then they most certainly would. They are not idiots, and I seriously doubt that a couple of kids on a game forum are smarter than an entire space industry made of thousands of scientists and engineers. It's not about not "wanting" a USS Enterprise, colonies on Europa, or free beer. I want those things as much as anybody. But unfortunately, what we want and what is physically, technically, and economically feasible in the foreseeable future are very different things. Having a overly optimistic or arrogant attitude about it won't change the laws of physics, engineering requirements, or the economy. Personally, I'm more impressed by the actual engineering that goes into something seemingly mundane like this: Than in pretty drawings that are totally impractical like this: That first picture is the NASA Docking System. It's a beautiful piece of engineering with many structural constraints, electrical and fluid connections, electronics, sensors, actuators, etc... It's a relatively small yet crucial component, but it has been in development for over 18 years (and it still hasn't flown). Yes, 18 years for a docking ring. That's how long it takes to develop real space hardware in the real world. So when I hear kids say "we can just build a spaceship and have a base on Mars in 20 years", it simply denies reality and the massive amount of development work that is required to build and design even the smallest pieces of an actual space exploration mission.

Who's goal? No government agency or organization seriously has that goal (except Mars One, but we all agree that their proposal is either a laughable hoax or a scam). We might get a manned landing in the next 50 years of we're lucky, or a small scientific outpost if we are mind-blowingly lucky, but a colony is science fiction. This forum is called The Science Lab, not The Science Fiction Lab.

Oh, and ULA has a proposal to develop the ACES upper stage into a tug/fuel depot infrastructure, which is cool. Again, I'm not sure how feasible it is and there isn't any real requirement from NASA to go forward. http://en.wikipedia.org/wiki/Advanced_Common_Evolved_Stage

I really wish we wouldn't keep on talking about Mars colonies when we haven't even kept someone more than a few days on any off-world body.

I think it's a matter of trade studies not making it worth the effort. Let's take your run-of-the-mill GEO comsat. It uses an upper-stage (Fregat, Briz-M or the Ariane EPS/ESC) as a tug to take it from LEO to GEO. These tugs go up with the payload, are relatively light, and standardized to reduce production cost. Once they have done their job, they are jettisoned and that's it. For example, the Ariane EPS weighs 1.25 t empty and carries 9 tons of propellant to put two comsats into GEO. Now, if you wanted to reuse one of these as a reusable tug, you want need to add some sort of standard docking interface, RCS, and a more complex avionics package, similar to the ATV for example. You would also need to bring it back to LEO for the next mission, which means that it would need twice the delta-v, and therefore over 2.5 times the propellant to do the same job. Now to refuel it between two jobs, you would need to send up a tanker with 25 tons of propellant to refuel your 1.25t tug. However, your tanker itself needs propulsion, docking hardware, avionics and attitude control, to be able to dock with the tug, so basically it will be quite similar to an expendable upper stage itself. So your reusable tug saves you 10 tons on the comsat launch. However, it requires a separate 25 ton to launch the reusable tug, and another 25 ton launch to refuel it for each mission. In addition, your comsat still needs attitude control, propulsion, and docking hardware to be able to rendez-vous with the tug. You've also introduced a lot of mission complexity, mission control work, and lots of possible failure modes.

Although it was getting close, NERVA wasn't operational when it was cancelled. It also isn't clear whether they would have been reliable to restart after several months in space, or whether they could be refueled and reused over multiple missions. On-orbit inspection and checkout would probably be problematic. It's certainly not what the Saturn-N upper stages were being designed for at the time. And they don't exist any more. The program was cancelled 40 years ago and the engines were probably scrapped (or buried somewhere in the desert). Restarting it now would require starting from scratch with modern fabrication methods, materials and safety standards.

No they don't. And there is more to a commercially operational reusable SSTO spacecraft than an experimental precooler proof-of-concept on a lab bench. It's a good start (after 30 years), but they still need to build a prototype of the SABRE itself, then a flight-rated engine, then an actual hypersonic airframe, then an actual space-worthy flight demonstrator with TPS. None of those technologies exist other than on paper. Then they can start working on reliability, serviceability, industrialization, and work out the economics of building a fleet and finding people willing to buy and operate them. The reason nobody is massively investing in Skylon is that, even if it does work, there is simply no market for the launch capability of a fleet of ~30 reusable SSTO spaceplanes. There is no demand for putting hundreds of 10 ton satellites into LEO every year. They claim that Skylon development will cost $6 billion (which is wildly underestimated) and that each unit will cost around $300 million. That means that if they want to recoup development costs, they will have to sell at least 20 of them, and more like 40 if you include the actual manufacturing cost per unit. Each Skylon is supposed to be rated for 200 flights and a 15 ton payload to LEO. That's a minimum market of 40x200 = 8000 launches. Over 20 years, that's 400 launches to LEO per year. It's crazy. For an operator, the launch cost will be $300 million for the purchase of the Skylon for 200 launches = $1.5 million for the hardware. Let's add (an optimistic) $0.5 million to cover operations, fuel, maintenance, crew, etc... so that it makes a nice round $2 million figure. There simply is no demand for such a flight rate, even at that cost. Some people say it will open new markets by reducing costs. Ok. Let's imagine that space tourism actually takes off. With a 15 ton manned payload module, you should be able to fit something like 10 paying passengers with 2 crew members = $150 000 per ticket for transportation to orbit. You need to add the cost of a space hotel and actual entertainment, plus a decent profit margin, which will likely put the price around $250000. Virgin Galactic only estimates the market to a few hundred people per year ready to pay that price for their service, so good luck finding the 4000 customers per year needed to cover your 400 flights. These are overly optimistic back of the envelope figures based on unrealistic development costs and 20 years of operation, and considering it actually performs 100% as planned. The actual development cost of the program would undoubtedly be closer to $30 billion (like the A380 or the Boeing 787) than to the $6 billion figure. Also, it is unlikely that an operator would want to wait 20 years for an actual ROI. And finally, it might end up with a payload capacity of only 7 or 10 tons to LEO rather than the expected 15.

I don't see why I couldn't. Flight hardware is a term, so flight vaporware can be. Quote from wikipedia: "Vaporware is a term in the computer industry that describes a product, typically computer hardware or software, that is announced to the general public but is never actually released nor officially cancelled. Vaporware is also a term sometimes used to describe events that are announced or predicted, never officially cancelled, but never intended to happen. The term also generally applies to a product that is announced months or years before its release, and for which public development details are lacking. The word has been applied to a growing range of products including consumer, automobiles, and some stock trading practices." You might only have heard about it last year, but Skylon is not something new. It has been on the drawing board for 30 years already. It started as the BAe HOTOL project that was cancelled. The 4 guys behind HOTOL quitted BAe and founded REL and have been working on it for decades without the funding to build anything. Recently, they got until now is some science grants and ESA funds for feasability studies and some lab bench tests, which is great, but unless they get several billion euros from ESA to build a prototype, or unless EADS or BAE buys them up, then it simply won't happen.

Space refueling and reusable space-based vehicles are something that still need to be developed. Restartable engines are not a trivial thing to make. Restartable engines that can be reliable after several months of interplanetary transit are harder. Restartable engines that are man-rated, and can be reused, tested and serviced in space, over several years and multiple missions are really hard. Although it's not impossible, the technology is not available yet. If we were to design a reusable ferry vehicle, the first iterations would most likely be limited to a reusable hab/supply/power module with an expendable propulsion module (tank+engines).