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User: DanielRavenNest

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  1. Re:The 666 Rule on Paul Allen Launches Commercial Spaceship Project · · Score: 3, Informative

    You are incorrect. A carrier aircraft doubles the payload to orbit relative to the same rocket starting from the ground. The energy and fuel saved might be only 3%, but if your payload to orbit of the rocket is 3% to start with, then saving 3% will double the payload to 6%.

    A carrier aircraft helps in several ways:

    * The actual altitude and velocity at the time you light up the rocket
    * Reduced g-losses. A conventional rocket starts by going straight up in order to get above most of the atmosphere quickly. When you are thrusting up, gravity fights you by trying to pull you down. This is lost energy. When you thrust horizontally, gravity is perpendicular so does not slow you down. With air-launch, you spend more of your thrust near horizontal
    * Reduced drag loss. You are starting above about 80% of the atmosphere, so reduce drag by that much.
    * Reduced pressure loss in the rocket nozzle. At sea level, you have to fight 1 atmosphere of air times the area of the nozzle exit. It reduces the rocket engine thrust by that amount. Starting up higher gives you more thrust for the same fuel used.

    You need to factor in all of those items to find out the true value of getting launched off an aircraft.

  2. Re:Why not use a balloon? on Paul Allen Launches Commercial Spaceship Project · · Score: 3, Informative

    High bypass turbofans like the ones they will be using are about 20 times as fuel-efficient as rocket engines. For one thing, they get oxygen from the air, and then the turbine pushes 6-8 times more air with the big fan, which goes around the combustion part of the engine.

    Starting at altitude helps you in three ways: (1) the velocity and altitude you are starting at, (2) less air drag flying through the remainder of the atmosphere, and (3) less back-pressure loss in the rocket engine. At sea level, the loss is 1 atmosphere times the area of the back end of the nozzle, which is significant.

  3. Excellent Team on Paul Allen Launches Commercial Spaceship Project · · Score: 5, Informative

    Paul Allen for the money spigot, Burt Rutan for the carrier aircraft, and Elon Musk/SpaceX for the rocket stages. When I worked on such concepts many years ago at Boeing, we generally found that launching from altitude like that doubles the payload compared to the same rocket starting from the ground, so it makes a lot of sense from an engineering and cost sense, as long as the carrier aircraft costs less than the rocket stages per flight (normally easy to do).

    This design overcomes one limitation we had at Boeing, which was the 747 was not quite large enough in it's current form. By going to six engines of the same size as the 747 uses, they solved that problem. Eventually they can also look at flying back the first rocket stage, for even more savings. Once it is empty of fuel, the rocket stage does not weigh much, so it would not take much in the way of wings, landing gear, and some small jet engines so it can fly to a landing. Without knowing how far it will go on a ballistic arc doing it's launch job, it is hard to say if it should fly back to the launch site, or fly forward to another landing location.

  4. Re:TV on Site Offers History of Torrent Downloads By IP · · Score: 1

    Not any more. As of a few days ago I sold my 2001 vintage rear-projection TV. I didn't watch it any more and it was just taking up space (if I want to watch a TV show, I do it on the PC, which has a decently large screen, and no commercials). Due to the weird pricing at Comcast, it's cheaper to have Internet + basic cable TV than to have just Internet, so I still have TV service, even though I don't have anything to plug into the cable at the moment.

  5. Phone Wars on German Court Issues Injunction Against iPhone & iPad · · Score: 1

    Will this era in tech history be known as the "Phone Wars"?

  6. Re:Take that... on Kepler Confirms Exoplanet Inside Star's Habitable Zone · · Score: 4, Interesting

    Kepler can only see planets with orbits edge-on to us, and it's only looking in one specific direction. For each planet it finds, we can expect there are 50,000 more that are closer. On average, the closest will be 30-40 times closer than the one it finds, thus 15-20 light years in the case of Kepler-22b. Still a long way away, but easier to get to.

    And no, the next best plan is not to explore it with robots, it's to use the Sun itself as a gravitational lens in a mucking huge telescope. To use it for that, you need to get to the focus distance of the Sun, which is more than 550 AU out. As a practical matter, you likely need to be more like 1000 AU out, since at the minimum distance you are focusing light that just barely grazes the Sun's surface, and the light from the Sun itself is hard to block out in that case. Farther away you can use an occulting disk to block the Sun + some margin around it.

    Because of the huge diameter of the Sun as a lens, you can get absurd levels of detail at a nearby star, on the order of 0.4 meters per light year of distance.

  7. Re:Take that... on Kepler Confirms Exoplanet Inside Star's Habitable Zone · · Score: 4, Informative

    Kepler can only see planets with orbits that are edge-on, so they pass in front of the star and make a noticeable drop in it's brightness. Make the reasonable assumptions that the orbits are randomly distributed, and stars with planets in the habitable zone are also randomly distributed. Then we should expect that for every planet Kepler finds, there will be one 7 times as close it does NOT find, and another 340 more in between those distances it does not find.

    Additionally, Kepler is only looking at 1/350th of the sky, in the direction of the constellation Cygnus. So add another factor of 350 more planets if you were searching in all directions. That gives you another factor of 7 in expected nearest distance.

    Think of it this way: Kepler was not designed to find every nearby planet. It was designed to find the ones that happened to be in the right orbits so that it could see them, in a small part of the sky. It will give us a statistical sample of planets, from which we can estimate the total population. For each one it finds, there are 50-100,000 more out there, which is a LOT of planets.

  8. Re:NASA on Institutional Memory and Reverse Smuggling · · Score: 4, Informative

    This is incorrect. When I was working for Boeing, who was contracting to NASA, I saw the Saturn V drawings with my own eyes, in the data repository building at the Marshall Space Flight Center in Huntsville, AL. They are punch card aperture cards, which is IBM style punch cards with a piece of microfilm stuck into it. If you need a paper copy, they print from the microfilm. There are about 3 million of those cards, filling stacks of drawers, with all the drawings and many of the documents in them.

    On the Space Station project, which I worked on for many years, we had a data vault at Boeing, which was literally a vault in the basement, where all the project data got copies stored, and we of course had to supply copies to NASA, who then put it in their repository. If there is one thing government is good at, is storing documents.

  9. Coming Down ~ Early January on ESA Ends Attempts To Pick Up Phobos-Grunt Signals · · Score: 3, Interesting

    From satellite orbit data posted at http://www.n2yo.com/?s=37872 I'm estimating it will re-enter in the first few days of January. Current decay rate is 1 km per day in average altitude from an orbit that is 215 km low x 310 km high points. This will double in about 14 days as it encounters thicker atmosphere, with doubling times cut in half each 20 km of height until it hits 120 km or so on it's last orbit. Since it has a large amount of fuel in tanks not protected by heat shields, it will a unique and spectacular "rapid disassembly" whenever reentry heating causes the tanks to fail. My best guess is around 80 km altitude.

  10. Re:Not Surprising on TV Ownership Declines For Second Time Since 1970 · · Score: 1

    I have my 10 year old rear-projection TV up for sale on Craigslist, since I don't watch shows on it any more. I had cut the TV portion of my Comcast subscription down to basic, since for some reason its a few dollars less for Internet + basic cable than for just internet. This year that is changing, and now internet by itself is a bit less, so out goes the TV part. Any shows I want to see I can download, without commercials, and watch when I want. That's a better product than broadcast, which is when they want, and with commercials. My larger PC monitor is HD resolution (1920x1200), so no loss of detail watching there.

    I expect in a decade broadcast TV will be in the same category as land phone lines are now. Still some holdouts who have it, but on the way to extinction.

  11. Re:This just in! on Judge Orders Hundreds of Websites Delisted From Search Engines, Social Networks · · Score: 2

    Maybe that's true, but a judge should understand "due process of law" and "right to face your accuser" and "the court's jurisdiction stops at the US border".

    By all means, confiscate counterfeit goods if they are found, and stop them from trademark infringement if they are doing that, but you cannot just forget about our hard-won liberties enshrined in the Constitution if you are a judge. Especially if you are a judge.

  12. Re:Risk vs. Hydrogen Bombs set off in the atmosphe on Will NASA Ever Recover Apollo 13's Plutonium From the Ocean · · Score: 1

    People also forget that the oceans are 3 parts per billion Uranium. So that column of water 1x1x6 km deep on top of the sunken RTG contains 18 tons of Uranium. Kind of puts it in perspective.

  13. Re:Hah. on Australian ISP's To Crack Down On Piracy · · Score: 1

    if you totally prevent online piracy, people will copy cds/dvds in between each other and still pirate.

    Maybe 5 years ago they would use cd and dvd discs. My current PC doesn't even have an optical drive, and I have not missed it much. These days USB solid state and external hard drives are more likely, or carrying a laptop over to their house. Sneakernet is very hard to stop.

    Meanwhile, online file transfer will simply go full encryption if they try to squeeze too hard, and move the title and decryption keys off somewhere else than the file itself (a private distribution channel).

  14. Re:Specifics on Maned Flights to Deep Space on NASA's Next Mission: Deep Space · · Score: 1

    The article is good as far as it goes, but they left out one key idea: mine the asteroids. Depending which asteroid, you can get metals, carbon, water, oxygen, and just plain dirt for radiation shielding. You can bring back 20-50 times your fuel used to Earth Orbit, or wherever you put your extraction plant. The most important thing to mine for at first is oxygen to feed your electric thrusters. That makes the mining system self-sustaining in fuel, and reduces what you have to bring up from Earth dramatically for all your other missions. After that, it's a matter of how smart you are in converting asteroid materials into useful stuff.

  15. Re:95% seems high... on Ubisoft Blames Piracy For Non-Release of PC Game · · Score: 1

    Interestingly, Crytek did an inadvertent experiment along those lines. The initial release of Crysis 2/CryEngine 3 did not include DirectX 11 for the PC, or the Mod SDK (which includes the Sandbox level editor). When those got released some time later, PC sales accelerated, and are still going relatively strong. Apparently the value of a game goes up when you enable community mods.

  16. Re:Winner take all system on New Media Giants Take Out Print Ad Against SOPA · · Score: 1

    The problem is the "winner take all" voting system, where 51% of the votes means you get 100% of the political power. Not only do third party candidates "waste your vote", but so do major party candidates in any area that leans towards the other party. Winner take all systems are inherently unrepresentative because all the people who voted against the winner end up not represented. We need a couple of fixes to the system:

    (1) Proportional representation - if you get 5% of the votes, you get 5% of the political power.

    (2) Campaign promises are contracts - if you break them, the voters are free to choose someone else to represent them, at any time.

  17. If they really want their attention... on New Media Giants Take Out Print Ad Against SOPA · · Score: 4, Insightful

    Google and Facebook can drop the politicians who support this bill from their respective sites....completely. Sorry, Congressman, you don't turn up in search any more, no Facebook page. Oh, and that email to your constituents? Sorry, gmail doesn't recognize your account.

  18. Re:Price disparity on Universal Buys EMI's Recorded Music Unit For $1.9 Billion · · Score: 1

    According to their "About EMI" page, they have 1.3 million songs in their catalog. So that works out to $1461 per song for the total rights to the song (not per download). Obviously some are worth a lot more than average, and some less.

    Universal, the buyer of EMI, is owned by Vivendi, who also owns Activision and Blizzard. So they own a ton of media properties.

  19. They own themselves... on End Bonuses For Bankers · · Score: 1

    Source: http://arxiv.org/abs/1107.5728

    They investigated the ownership and control of ALL 43,000 trans-national corporations (TNCs), ie ones with business in more than one country:

    "We find that, despite its small size, the core holds collectively a large fraction of the total network control. In detail, nearly 4/10 of the control over the economic value of TNCs in the world is held, via a complicated web of ownership relations, by a group of 147 TNCs in the core, which has almost full control over itself. The top holders within the core can thus be thought of as an economic “super-entity” in the global network of corporations. A relevant additional fact at this point is that 3/4 of the core are financial intermediaries.

    The core is also very densely connected, with members having, on average, ties to 20 other members. As a result, about 3/4 of the ownership of firms in the core
    remains in the hands of firms of the core itself. In other words, this is a tightly-knit group of corporations that cumulatively hold the majority share of each other."

    This was the first "World Wide Web". The web of corporations that control pieces of each other. The ultimate owners, rich individuals who own stock directly, then control vastly more power through this web than if the companies were truly independent of each other.

  20. Re:True to every corporation on End Bonuses For Bankers · · Score: 1

    If we assume that the probability of a bank screwing up and losing it's shirt is independent of size, then we should limit the potential damage by limiting how big a bank can get. There should also be a stronger risk premium for screwing up. There are two ways to do that. One is weight the FDIC premiums against *all* financial risks vs. bank capital. If the bank is carrying 100:1 ratio of loans, derivatives, etc. they should pay a correspondingly higher premium than a bank that only is leveraged 10:1. Alternately, the FDIC only insures a limited basic amount of deposits. If the bank wants more, they have to get commercial insurance. The insurers will price it by risk. Then the variable amount of deposit insurance becomes a signal to depositors. Right now everyone has the same amount of coverage, so there is no reason to investigate how sound the bank is.

  21. Re:Secure systems on DARPA Seeks Input On Securing Networks Against Attackers · · Score: 1

    The Internet was designed to be damage tolerant, not secure. So it is fundamentally the wrong design for a secure system. Instead, the current internet does it's best to *deliver* data. So likely their best choice is to build a new network from the ground up, designed to be secure. That probably means *not* based on the Internet Protocol.

  22. Re:Not a result of Global Warming. on Cracks Signal Massive Iceberg Forming In Antarctica · · Score: 1

    If the ice shelf breaks away, it gets out of the way of the glacier that is still on land, which then accelerates. This does add more water to the oceans, and so raises sea level. In fact, the Pine Island Glacier has accelerated since people have been monitoring it, and the ice shelf, when measured after each iceberg breaks off, has been getting smaller.

  23. Re:Curious if there's any informed people here... on Fee Increase Attempt Inspires 'Dump Your Bank Day' · · Score: 2

    The new $0.21 per transaction limit on debit card fees are still about three times what it actually costs to process the transaction. It's electronic transfer of funds. In theory the cost should approach zero. What little cost there is is partly to do with having to produce a physical plastic card, the human paperwork to set up the account, and the occasional odd charge or fraud, when a human has to get involved.

    So cry me a river that they can't charge more than three times cost on debit transactions. Maybe that will force them to become more efficient.

  24. Re:What do CUs do with your money? on Fee Increase Attempt Inspires 'Dump Your Bank Day' · · Score: 1

    Both banks and credit unions make the majority of their income by making loans. The difference is credit unions are owned by the members, and operate as non-profits (excess profits are returned to the members), and they typically don't have huge office buildings downtown with multi-million dollar executive salaries. Because they don't have to earn a profit for shareholders, or have the extra overhead of megabanks, the can give a better deal for customers. That can be in the form of lower fees, lower loan rates, or extra services, and the mix varies by credit union. At the local branch level, banks and credit unions have about the same costs for tellers, the building itself, computers, etc. The difference is outside the branch, in the extra profits required and overhead for a big bank.

  25. Re:Who still uses Pirate Bay? on Music Industry Pushing For BT To Block Pirate Bay · · Score: 1

    According to Alexa ( http://www.alexa.com/siteinfo/thepiratebay.org ), it's the 79th busiest website in the world, visited by around 1.2% of internet users per day, which is an increase of about 1/3 over the last two years. Additionally the number of internet users as a whole has grown over the past two years. As a techie that reads Slashdot, you are likely ahead of the curve. The general population is still catching on to this torrent thing, and the other methods of getting content, which includes the legal ones like Netflix.