AngelLestat

I forget about this one, not sure in the Martian, but interstellar does not ignore the radiation factor, the black hole accretion disk as you can ""see"" in the movie bright on the visible spectrum.. That is because is a old residuary accretion disk in cooling process. What I ignore is the radiation blue-shift when you get close to the black hole from the accretion disk.

50% loses on friction in the pipe?? In each trip? Those loses are close to 5% for the pipe that goes to the tank. To reach 50% loses in friction you will need a labyrinth of pipes of small section. Why you quote me if you dont read my quote? Another thing that I dint mention is that a new tech left its prototype stage and now is entering for commercial use with plants already in construction, you can convert natural gas or methane into hydrogen capturing all the co2 in form of soot that you can also sale. The system has a efficiency of 75% and a production cost of 2eu by m3. Ok, but is not all about efficiencies, you need to include the cost of each method. Also let me correct you with air storage, today the efficiency reach 75% because you capture and reuse the heat that before was waste it. Also.. Fuel cells are unproven? The chemical efficiency can reach 60% in a triple cycle, fuel cells can reach 80% if you use the heat as cogeneration. But yes, we need to learn to use the energy in a more efficient way, today most factories waste a lot of energy that can be used to increase the efficiency of other factories or homes. Solve the intermittence problem of renewable energy sources is super easy and cheap when you include smart grid, cogeneration and hydrogen and methane production. Is not for county scale, but when the terrain is appropriate is a very good option. The part that is energy density is not high, that is not quite accurate. If you have a cube tank of 2 meters, you get 8m3... but if you increase the side just for 1 meter, then you tank now holds 27m3. That is how a small and cheap lake like this can storage 30mwh.

Here there is a book that all critics should read before write silly things. I also explain some of these points in this old post: That is not accurate, is a rotating black hole, miller´s planet orbit is at 0.45c. This place millers planet at more than 3 Au from the singularity, the even horizon has a radius of 1Au. I prove it :P, and the friction coefficient that I took was correct, the problem that you picture in your head the wrong example, there is not a perfect 30 degree slope with grave and very thin dust on earth which does not sink over your foot to change the angle in where you can compare with your experiences. And even if we rise the friction coefficient, 100km wind in earth can make you blow away if something hit you like in the movie. You can doubt about the 400kmh wind on mars equator everything you want, I dont have that kind of evidence and I assume it will be very weird. But under those numbers, you can't denied that is very accurate even if the same writer dint knew it. Read the book. It has its flaws as any movie who is more interested in the story than in their 0.5% science followers, but most of them are not the ones that everybody thinks.

How can I do to not let spaces in each line that I press Enter? Also.. there is a way to use the last quote tag system? Elon just said that (in my opinion) to increase the confidence of his clients in his car. But that could help in the short term, but those words would come back as a boomerang to hit his ass. We already had this discussion in the topic lithium vs hydrogen, in that topic I said that for small vehicles (less than 1500 kg or for high acceleration cars) batteries has sense but for anything big than that fuel cell has more sense. Maybe not just now.. but for sure in the next 3 years (depending location) will be. Now all big car companies are making their hydrogen car, not just toyota and honda. So you think they are all wrong and Elon is right? I am a Elon fan.. but I know to disguise between strategic propaganda vs reality. ??? ehh? Hydrogen is made it at big scales using steam reforming, but is not used in cars because that market is not really here yet. Is used to make fertilizers. About electrolysis is the same at low scale than big scale, the only thing that matter here is the catalyst, right now the best is platinum which is very expensive, but a lot of new technologies are rising to remplace platinum with other materials without losing efficiency. But even with today hydrogen production disadvantages, Germany already had a net of stations that produce hydrogen at 700bar or in the new standard 350 cryo-compressed (not liquid) when they need to storage energy. The math is easy, batteries become very expensive to move heavy things or for long range. But in the hydrogen case, you just need a bigger tank which is not expensive, also you can recharge the tank in no time. Right now you will find a lot of articles talking about hydrogen new techs, cars and long scale country plans. In the Paris convection all countries are reaching an agreement that they need to move one step further into the hydrogen economy. Because when you talk about energy storage, there is not battery, flywheell or any other technology that can be close to match the storage requirements needed at country scales as hydrogen or methane (capturing co2) can provide. Countries can be 100% renewable, and many are taking that step right now. It was after a study ordered by europe community which was made in finland. Where they find that they can change to fully solar and wind (including transport) without increase more than a 10% their current energy budget. Is easy, when you have extra energy (that it will be most of the time) you make hydrogen and methane. Compress air comes second as big scale energy storage alternative. Of course, as always, I can backup everything that I said with evidence and logic in case someone needs.

Dragonv2, it will come with many innovations, which in my opinion the abort escape solution merged with propulsion landing is the best.

The martian storm (if the winds reach 400kmh as its mention) can blow up a person with a space suit without problem. We already had this discussion and I prove it with the help of Peadar1987. 400kmh wind on mars is similar to 150kmh in earth due its low reynolds number and the lower friction due its gravity plus dust in the air that increase the density. About Interstellar mistakes.. take care on those ones too.. there are less than everybody thinks.

oh.. a big change in the forum looks, I thought that I miss the page. Here you go: https://www.easycalculation.com/physics/classical-physics/potential-energy.php You need to calculate the potential energy, lets said that you have a building 100m tall. In the top you have a 30m3 tank. The same pump that is used to raise the water can work as generator.. Electric motors has close to 95% efficiency. 30m3 = 30000kg if we rise this 100 m then we have 29400000 Joules --> 8,1kwh -10%= 7,3kwh Which is not much for a 100m building Also not sure how to do to not waste a part of that water without big changes. But it was not a bad idea... People should think in ways to improve the efficiency of all our systems. This is not so hard as many may think, because we never needed before (when oil was cheap and co2 dint matter) Other company plans to do the air compress bag idea but at 1000m deep, capturing the heat of the compression before send it to the bag.

Hard to find a better word to describe it. By the way.. here some tips on quotes: Once you have all the text quote ready to reply, start to reply just under the text you want to reply erasing the rest, you just need to add a [ /quote.] at the end, or use the quote botton (which add both quotes needed) for extra text. Nasa should lead the way in technology, they also need to do all the missions and risky things that private entities cant do, they should be the first to try reusability, aerocapture, new tech approach or other things to lead the way and guide other companies how to do it, but they are doing all the opposite, they are freeze in time and only spacex is trying new things. Erosion? That is concrete, the material used in dams, besides you only have a flood enoght to open the first way only 1 or 2 times by year, and you need a really strong flood to open the second way (1 every 5 years). Also I was thinking, if you have some holes from the first level to the second, and the second to the third, you can let escape the air to the top of the tunnel, so there is not need to support all the water weight, because it will be submerged. At least that is the way I will do it. If you use a heatshield, you can do an intermediate maneuver between Aerobraking and Aerocapture, without insertion burn. This would be much more safe than both. Veritas has 500 millions and davinci another 500 millions as max. If you merge both missions (you keep the different teams) you have 1 billions, you will tell me that add a simple ballon with a camera and some instruments that only needs to last 1 or 2 weeks (before it reach the hurricanes in the pole) will cost so much? When you merge missions, you dont need to think so much how to deal with every single step of the mission (launch, insertion, capture, transmission, etc) for each probe. Aerocapture too risky? We will see what NASA scientists have to say about this: http://www.lpi.usra.edu/opag/archive_documents/aerocaptureRisks03_08.pdf http://solarsystem.nasa.gov/docs/Concepts_Munk_Spilker.pdf Aerobraking reliability = 0.984 Aerocapture reliability = 0.994 I love destroy some myths, especially when they are founded simply by what NASA does or not, as if there were a holy guide of what is correct or not. Not sure why is so hard to believe that NASA managment are terrible to take decisions. An extra way to aerocapture or aerobraking: http://www.parabolicarc.com/2009/04/22/global-aerospace-developing-ballutes/ The heatshield generates a shockwave, that shockwave can be intercepted by the ring ballon, which achieve extra drag with low area, you can detach it when you achieve the orbit needed. By the way, you can also have manned missions to Venus.

The mass is not my main point about why it would not work as relay, but let me point that the payload of the spacecraft is 35 kg, then you have like 300 kg of fuel, +tanks, PV, engine, etc. The main reason is that was not designed for that, neither the anteena, the frequency, the orbit, power, etc. It may act as relay if you find an emergency and the japaneses are willing to change some of their procedures and software to allow this. But lets be realistic, it would not be used as relay, it can be used as support. Is already buiilded and working since 2009, the real cost is the tunnel, the extra support is just steel bars. There is only "enormously complexity" when you lack of talent (or good guidance) in your team. NASA should encourage to try new approaches to reduce the cost of missions, but it seems they dont have problem wasting always the double in each mission leaving so many others behind, we can not continue with this approach for always. You already need a heatshield for the lander (and for a floating probe if is included), so why it can not shield the orbiter too? After the first pass, when you reach your apo, you detach the orbiter, this execute a circularization, and the other 2 proceed with reentry. Or you can do it in many pass as aerobraking (which is not risk because you have a heatshield anyway) This is the easier planet to practice this (more than earth or any gas giant), It is a maneuver very needed to reduce the cost of any kind of mission, an inflated heatshield with many pass is not risky at all.. is a lot more safe than when the magallan did it without heatshield in 1989!!! What is the excuse now? How much we need to wait to make these manuvers that are totally necesary for manned missions? Is an atmospheric probe, but it land and will transmit from ground, that is what I remember. I dont understand the new frontiers or discovery point, can you elaborate?

The akatsuki probe was not designed for that, so not sure if can repeat the signal, also its eliptic orbit it will be 300000km to 5000km. It has a mass of 45 kg, so not expect much. The first Venera missions dint have a relay bus in orbit to transmit the info, but they needed to transmit just temperature, pressure and few other parameters. For the next Venera missions that was able to transmit images, they used a relay bus in orbit. This also reduce a lot the mass of the lander probe or atmospheric probe. You also need high bandwidth to transmit all your data if the atmospheric or surface mission are not designed to last much time. Instead you can transmit in high bandwidth to an orbiter probe, and then this orbiter probe can take all the time it wants to transmit the data back on earth. Not sure if I can said that I will be surprice if NASA not choose to fuse these 2 missions, after all... they are NASA, which is not a synonym of efficiency. Any good design should try to solve as many issues with one solution. The Kuala Lumpur tunnel that works as highway and channel to avoid floods on the city is a perfect example of that. https://youtu.be/w4MelscxP3A?t=36s Merging missions is the best way to reduce payload in a considerable way, not need for extra heatshield if you plan to do aerocapture, not need for a lot of energy and a big antenna in each probe to transmit the data and one launcher. Now each of these 5 missions will receive 3 millions each to improve the design for the final selection step, again.. it will be very dumb if veritas and davinci team does not join efforts to fuse the missions, they can also include a floating probe for the same cost.

The venus missions needs to be done together, because the Venus Express end its mission in January of this year, so there are not current orbiters in Venus. The deltaV requirement for venus mission is the lowest from all other missions if they use aerobraking or aerocapture (venus is the most easier object in the solar system to perform this kind of maneuver, it was done 2 times in the past already, both successful) So you can increase the payload by a 80% to 120% depending the manuver choice. I think they will fuse both mission with a single rocket launch. Veritas sounds fine (there are not many other things left to be done from orbit in venus), Davinci is ok for a lander, taking measures and pictures meanwhile is falling, they already have the electronics to stand the heat long enoght. This probe can be light and small. If they add a ballon to the sphere and they inflate with water vapor, it can rise again, let the instruments cool down and then land again in a different spot. They can also include a third probe, which can be very light and amazing in its functionality. A mixed ballon with water and ammonia can cycle heights between 40km to 60km over a 6 hour period using the thermal differences of the atmosphere which it would condensate and evaporate water/ammonia at different levels. Choosing the insulation and the amount of water/ammonia, you can choose the cycle levels and the period with higher accuracy. It can also help to let the instruments cool down and measure a big portion from the atmosphere. Valves and heat-pipes can be added to control the condensation and vaporization, which allow full remote control of the height.

It needs perfotarate the ice crust, that requires a fair amount of energy. EDT in mars was achieve it many times, but still is a hard task. Ok I should have knew that they would choose 2 missions for venus, they need an orbiter to repeat the signal from the atmosphere probe. But now they change it for 1 descent probe instead a floating ballon. I think the floating ballon should be more important taking into account the possibility to sent a manned mission. Also it would not require much more money include a floating probe in this "venus pack". Lucy seems a very boring mission, not sure what is the rush to know the history of the solar system (which I doubt that it would get too much evidence), now we need missions to work as precursors from the next important missions.

If it depends on me, I would go for these in this order: VASE (Venus Atmosphere and Surface Explorer) Enceladus Life Finder Psyche Mars Icebreaker Life: This mission can only enter in that budget if they become very efficient in the development process. Something that is very hard to believe, also PV does not seems to be enoght. If it would be possible to choose another mission that is not included in that list.. I would choose a solar sail mission. After the development fail of sunjammer, we delay this technology like 4 years, and is very important to master this as soon as possible.

I will translated for you: if some agency wanted to make now a similar manned mission to the moon (with many improvements), it will be possible with today NASA budget. Now NASA has the same amout of money they had back then even with inflation corrections, with the addiction that now technology can help us to reduce the cost in many aspects. Back then, if you wanted to make big steel tanks, you needed to reform or make new factories just for that job. Now a lot of factories can do it for you with better materials and costs. The GDP increase rates are already adjusted to inflation corrections. NASA use the lower % with respect to the GDP they receive as an excuse of not being able to do the same thing now than back then. But this is a lie, more if we have into account they use the same engines from the shuttle and delta4 to make the new SLS. If you want to understand inflation and GDP: http://www.investopedia.com/articles/06/gdpinflation.asp Simple example: Lets said I won 5000$, and I give you 1000$ to do something, the years pass, and now I won 15000$ but I still give you 1000$ to do the same thing, you can not said that you can not do it because the % between what I won and you receive is not the same if the inflation was already adjusted.

It would not be an easy way to get down from that thing. This does not require too much more mass: http://s20.postimg.org/jdf1f7a7x/Moon_Artificial_Gravity.jpg ??? saturn V was the first rocket of this size build it in 60th with all new tech, the time it took to build it in fact decrease the overall cost, but the money you need to invest by month is much higher. The saturn V was not more expensive than the SLS, as you said 17 was build + devepment cost (not sure what is the SLS excuse now) Many times NASA makes the excuse than back then they had more budget in % to the GDP. Which is true, but this does not mean they had more money... you talk about inflation, but the increase in GDP is not all "inflation", inflation is when you can not buy the same things with the same money than before. But here there is another factor, the population grew and become more efective to obtain resources from earth, so now the country makes more money (in base to their resources), it does not matter what % of the GPD you are getting, because a big part of that GDP is new money without inflation. That is why zubrin said that NASA now has the same money they had back then. Take a look, there are graphics who take into account these factors into the NASA budget, you will see is the same almost.

You waste extra energy in heat, but still even if you ignore that, you are far far from solving the bouyancy problem. In venus, at 50 km, each m3 of co2 weight 1.6 kg, so if you remplace that with hydrogen you have 1.5kg of netforce by m3. Now in saturn at 15 bar, you have 1.5 kg by m3, but even if you have a thermal difference of 80K degrees, you would lift only 0.3kg by m3 (aprox)

Gravity would be lower in saturn than earth if you are in the equator due centrifugal force. 1.06g in poles, 0.9g equator. The problem with pressure is not "crushing" if your habitat air pressure is equal to the outside. The only problem is the breathing gas mix, you need to keep the same amount of oxygen (not ratio) and avoid the limit of your secondary gases as nitrogen, helium, hydrogen to not produce bubbles when they are in your bloodstream. Also some become toxic as oxygen to certain levels. Our bodies are incompressible, if we have the same pressure in our lungs than outside, we would not notice any pressure. But saturn layer temperatures similar to earth (the same as other gas giants) are below the limit of breathing gases, which is close to 50 to 100 Bar. But that is not the only problem to live there, in venus is pretty easy to float because the 98% of the atmosphere is co2 which is heavier than oxygen. But in saturn the 95% is hydrogen and hellium, so no matter how deep you are, you will need to find something lighter than those gases.. The only way is heating hydrogen, but the netforce difference will be still much lower than heating earth air. So is very difficult to float in the gas giants.

You are right, that is a valid point If you are far enoght, the angle is not much affected but the time it will take you increase, because the gravity would be significantly lower.

If I have to choose a method.. I will capture big asteroids of ice, then I would place them close to the moon in free falling firing "asteroid material" to keep altitude (gravitation pull), the propulsion method will be salt water rocket (in case is possible), so we take the salt and water from the asteroid, and we just carry the plutonium or uranium from earth. With many of these.. eventually we can slow down the moon.

If is all about mass, then to have the same shielding than our atmosphere, we need 10 meters of water between us and the particles. Not sure if this is right or not, it depends on if mass is the only factor.

I never published any papers, but I read many papers and I also read advices for those who publish. Is true that you dont need to provide a theory, but if you want to relate different statistics without apparent relation, it would be much better receive if you have something else to support that relation, in case you dont.. the academic community is also integrated by people... so their responses can come in many flavors. Also at earth distances.. you are talking more about solar wind than "magnetic fields".

About what? that it should be too weak? Also taking into account cantab´s quote from that organization, then it should be ok, they are publishing their results to that site, or due to request and encouragment of that site. Which is not the same than publishing to the open scientific community.

poor "scientists", trying to publish this paper without even a theory (or maybe they had, but is not mentioned in the article) of how this "not even measurable" force at earth distance may cause that. I wonder what it would be the reaction of the community. If I would be in their position, I would just make a comment like.. "hey.. look, what weird coincidence of this data relation.." and nothing more until I have a real theory to explain that. Publishing by other hand..mmm bold move.

Few km close to the surface already rain metals. Also not sure if you heard it, but they already have chips to stand almost surface temperatures, which they need very low cooling, they already said that with extra development they can achieve chips without the need of cooling. But well, going back to the first missions. The best advantage of venus, is that you can drop anything to the atmosphere, it will float at 50km, then with PV and proppelers you can dock with any other airship in venus. There is not danger to crash or break your head with EDL calculations. A first mission to venus is many times easier than mars.

that is the ugliest rocket that I ever see..