AngelLestat

They are cheap because is a private company which really cares about how to optimize cost.. In a goverment company is like: ok, I will use the best of the best and make 100 test on each part from my area so if something happens they dont point to me.. The money comes from above.. so there is not problem.. This same thing is applied to the politicians, there are only in danger if they force to someone to work with less budget than the average. So every body just spent a lot to avoid responsabilities. I remember you that the structural safety margins in falcon 9 are 40% above flight loads, higher than the 25% margins of other rockets. So when you said cheap tanks or cheap things.. it has nothing to do with the actual quality of the components. It has to do with good production procedures.

Also another point.. After the launch and reentry.. you are igniting the engine again to land.. That is the last proof that all still works. About vibration and structure streess... Its designed to stand that at a lot more. You tell me that every time a 747 find turbulance they need to check all the airplane again? Also.. a 747 is much more complex than a rocket. My washing machine every time that centrifuged is like an 12.5 earthquake, and after 3 years since start with these unusual shakes still works.

Take like example something so complex as an airplane. They fly all the time, they get 1 check every 1 month approximately, full check without disarm engine and without change parts if they dont need to. When I take my car to the mechanic, after I leave there is always a big chance that something did not work as assumed. Sometimes they forget something or they dont adjust all pieces fine. So it may lost some oil, or water, or it may gain a new noise, etc. The best test that something can have is carry out with is duty. As Rakaydos said, if had a soft landing, not salt water, not reentry heat do it to retro-propulsion; then you just need to check if all connections looks ok, electrical and hoses... Some structural check and thats it. It will be more reliable to launch a rocket already used without check, than a new rocket with months of checks. That is why they can save so much money if they accomplish this.

No.. if you touch something that is working.. you have the chance to introduce a problem. If it works.. it works. A simple review and system study it will be enoght. The engine design is to stand like 15 (I dont remember) launches without remplacement. This is not a F1 car where the engine only last 1 race. Also you can test all systems combined just 1 time... in the launch.

They save a lot of money in tests, because they know that all works with that stage.. Just needs some revision and check before launch which is nothing in comparison with the checks needed against something which never was tested.

That is exactly my opinion. Maybe in some test worked very well, but was pointless in other test to become practical. But after 35 years only the possitive opinions and info remains which may be distorted by the same inventor. But well, I have not proff of this. StreetWind: Yeah it seems weird also from this perspective, but there is many things that we know it works but we can not figure out why... Only 1 year back we be able to understand why the shell and the glue of some molluscs was so effective with tons of samples.. Is not easy to do reverse-engineering from something we can not see or study.

Somebody can believe this ....? In the 80s, an amateur scientist named Maurice Ward discovered a new not flammable material, very good insulator and light called Starlite. The material was a dream and something that we are far to accomplish even today, it seems that he wanted billions for it. Many were intested like NASA as a better remplacement for heat shield materials. There were several tests over the time and exceeded all. For example it could resist a laser at 10000 celcius between many other things. He always keep the 51% of the formule into secret (some kind of plastic) and he dint wanted to patent to not publish the formula. He died in 2011 carrying his secret to the grave. Now it seems that his family are the only ones who may know the formula. http://en.wikipedia.org/wiki/Starlite http://mauricewardstarlite.blogspot.com.ar/2009/03/hello-one-and-all.html https://www.youtube.com/user/mauricewardstarlite/videos Everytime that I hear these stories I become very skeptical, but I can not find any evidence to point otherwise. Is weird....

I cant not understand the reply, if you want to add some info to explain better all this your are welcome.. But is like you are correct me from things that I dint mention. When I said that you need einstein relativity with quamtum mechanics for anything from the event horizon and beyond.. I was talking about the fusion of those 2 theories into a new one. Then to resume I just said relativity is enoght if you are close but not in the event horizon.. Of course that if you wanna study something small in the universe you will always need quamtum mechanic, but you dont need a new fusion theory. Also Newtonian Physics does not have into account that the light can be bend due gravity. About the equilibrium example I dont get it.. I am not talking about the black hole.. Just the photon sphere which that area will looks brighter. Another way to explain this, forget the accretion disk, just imagine 6 stars, one in front, back, right, left, down and up according to the black hole. From your point of view far from the black hole you will see only the star that is in from of you in case the black hole is not there. So only 1 point of light without the black hole. Now if you put the black hole you will see some photons from the 6 stars reaching your eyes. And the point where you see these photons is in the photon sphere, because all comes from there. So yes... that area it will be brighter.

this topic was already post it in the science section.. Yes is possible and it was done several times (like 30). They possition the ship in the equator to be able to increase the payload for the rocket they were use. Search the old topic.

boooriiiiiing.... we need to wait 15 years more just to accomplish the same than in the 60th without any other real objective than "be there". Even that is far more cheaper than a Venus or Mars manned mission, it will have way less support from the people (which in part determines the mission budget). The news of this event when arrives in 2030 it will be seeing just as something important to talk that day.. I personally I found more interesting spacex achieving recover the first stage than back to the moon. Because that is something that has real value for us. Visit Mars or Venus it has tons of value that can not be compared with nothing, we can found life in mars.. we can found the key to understand and solve global warming in Venus, we can make the first steps in what may be our next home.. Some may think that have a base on the moon may be the perfect step to travel other planets, but is not. In any case if you want fuel waiting outside earth, just capture an asteroid and mine its water. Or do what elun musk is trying to do.. a cheap way to launch things.

Is what I said in my first, also I was agree with Nful explanation. All photons escape eventually.. they may do 1 or 5 turn around the blackhole, but then escape and some reach you. Remind that there is a huge amount of photons, even for a distant start. So it will be many photons which are comming from behind you,, then their turn around the black hole and back to you. That is way that zone is brighter, because you can see photons comming from all directions from the universe and escaping in your direction. If you are in the same photon orbit, it will be more bright (as any light source where you get closer), the speed of light is always the same), so you can see the photons there.. And remember that there is 2 photon sphere, one which photons orbit in the same direction of the BH rotation, and a second one farthest, which photons rotate in opposite direction from the blackhole spin.. About quamtum and relativity.. that only counts from the even horizon and beyond. The photon sphere is in einstein ground.

yeah as NFUN said.. I guess there is always a bit of light from the star background which we would see as an unfinish ring around the black hole.. If it has an active or old accretion disk as photon source then there is not necesary to imagine, Interstellar did a great job showing how it will looks like. Movie http://www.dneg.com/wp-content/uploads/2015/01/Interstellar-FLprStills42.gif With the effect from the rotation effect which was not added in the movie and is not fully renderized here: Rotation: Bright space comming to you, dark in opossite direction.

No is not. Not rotating black hole. A most real Rotating blackhole

Yes. this remind me ring world too from Niven. First the option A is not possible no matter if you make all the ring from perfect graphene. Is like have a 1000km bridge without any support, at that height the ring curvature does not help you in nothing to support its own weight. If you make the ring spin to orbit velocity then it will be unstable and crash anyway (not sure, hard physsics). But there is an option X which may work: You need a series of magnets orbiting in ring shape (not connected between them and faster than its orbit velocity), those would act as your bridge support for a superconductor ring which is not rotating. You can adjust the speed of each individual magnets from the ring it self.

they have some nice ideas.. like cryo ballon tank for the last stage, engines recover with parafoil chute (the helicopter part mmm...) and other few things. I dont know.. I like more the spacex approach or the "real vulcan (russia)" approach. Why they copy the name? even it looks similar..

Yeah it may work.

Oh, I was totally forget of today launch, lucky that it was cancelled heh, dont hate me.. I was in that place many times, and maybe I will be tomorrow.

hi, is the first time that I see a blast calculation so I can not help you with that and there are many things that I dont understand. Also my logic tells me that in case that your calculations are correct, that must be true only for blast which source and medium is the same gas. Also not sure how to calculate damage by a pressure blast force.. One thing is a force applied to only 100 cm2 and a very different thing is that force equal applied to each point (inside and out) of your body. That force may looks scary for an object hitting you but not so much as air pressure. Mountain climbers deal with 8% of O2, and they do it under a high physical activity. Not just sitting in a car.The toyota Mirai carry only 5 kg of hydrogen which gives 165kwh, the Tesla S only has 85Kwh in its batteries. Also there is not way that all those 5kg of hydrogen will remain in the car for more than half second. Cars are not pressure vessels or air tight. And as I said, hydrogen cars already are designed to let any leak escape from the car with ease. 700 bar hydrogen tanks only are in danger when overseed 1600 bars. The tanks resist any fire gun shoot, to be able to pierce them you need .50 caliber barret. And if you do, the hydrogen leaks by the hole very quickly without explosion. Also the tanks come with pressure release valves in case over pressure, plus 15 extra valves with a complicate hardware system to act the best way against any different problem. The tanks are in the less vulnerable part of the car. Expert said that due all these precautions h2 cars are even more safety than any other car. So less put the "hydrogen danger" aside and lets talk about the real drawbacks. Pressure Hydrogen transport and management comes with an extra cost which it will be notice in the car and the fuel cost. That is why I think it will be more cost efficient to use ammonia for any +1500kg vehicle with the airplane exception. For planes h2 cryo tanks works much better. That is true for instant 0, but to get impulse you need a force acting on time. I am not sure, but I still believe that is not the same two 100 liter tank at 700 bar one containing hydrogen and the other air which has 12 times more mass. Oh, long time that I dint check this site.. they growth up a lot.

Hydrogen is less viscous, it will diffuse faster for any open space than keep pushing against something else. Even with that pressure you have only 5 kg of gas there, if you have a similar tank with air you have many times that mass, which will push with more force the tank parts or the air around. http://www.arhab.org/pdfs/h2_safety_fsheet.pdf "Hydrogen has a rapid diffusivity (3.8 times faster than natural gas), which means that when released, it dilutes quickly into a non-flammable concentration. Hydrogen rises 6 times faster than natural gas at a speed of almost 20m/s. Therefore,unless a roof,a poorly ventilated room or some other structure contains the rising gas, the laws of physics prevent hydrogen from lingering near a leak. Simply stated, to become a fire hazard, hydrogen must first be confined – but as the lightest element in the universe, confining hydrogen is very difficult. Industry takes these properties into account when designing structures where hydrogen will be used. The designs help hydrogen escape up and away from the user in case of an unexpected release. " The electrolysis does not add weight.. the only that can add weight is the compression. But nobody said that this needs to be in your car.. You can have one in your house. Ok, I dint understand that part.. thanks to clarify. My point is, lets not exaggerate. 95% its efficiency. Also read about ammonia storage in previous post.

You are right, I mix some numbers from old hydrogen tanks or cryogenics. But industry is not searching how to reduce the pressure, in fact they wanted to increase using lighter materials at the same time. But what about ammonia? In 2014 they found a easy way to cracked back to hydrogen, you will lost only a 10% in efficiency in make ammonia and then craked, but it will save a similar amount of energy in the hydrogen management. Small cars like 1500 kg or less had more sense with batteries. But beyond that hydrogen will be the most efficient choice. yeah is possible.. but still not sure how severe would be a 700 bar h2 tank explossion vs a 700 bar air tank. The h2 diffuse faster so it does not provide (in my theory) much acceleration to the tank parts as it will any other element compressed under the same pressures. How can be filled if it is so diffuse? Also how do you extract the o2 from inside your car? Also pitched voice.. It all depend in how cheap will be the new catalysts in the future. Is funny how all arguments against hydrogen only has 1 case to point in 1930. Hydrogen is flammable.. so it burns with air.. the same han all the history fire caused by oil derivatives. ah it seems that we are talking about antimatter now.

But you can be even at 300 km without any orbit velocity, or equal to the earth rotation, this mean that you will fall and crash in the next moments, the same that any else will do even with less altitude. Of course if nobody really define space before, or there is not consensus about that, then is open to suggestions. In my definition (that of course it may have many loopholes) I take into account in some way what happen if re-entry by atmosphere brake over time.) But well, who wanna try to define space without many words and loopholes? If you wanna try to define a law, how it would be?

in my opinion.. space begins were your spacecraft would not fall due its speed even if it try it. So if it travels above a country, it can not do nothing to avoid that and there is not danger to fall over this country. In case if it does.. it may disintegrate, if it does not.. then your are violating its air space.

special shear-thickening fluid: why this sound equal to a non newtonian fluid?

they escape eventually not matter how perfect is their location, but the orbit will be very bright (not sure if it is the word).