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Space news /comments

Discussion in 'Off-Topic' started by Winner, Mar 25, 2012.

  1. Valka D'Ur

    Valka D'Ur Hosting Iron Pen in A&E Retired Moderator

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    You are aware that the Vikings' Greenland colonies died of starvation? Greenland was colonized before the turn of the millennium-before-last. The Newfoundland settlement came shortly after the turn of the millennium. That's over 500 years before Columbus.
     
  2. Winner

    Winner Diverse in Unity

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    Neil makes some good arguments concerning the secondary benefits of space exploration. He should really double his efforts to inform the public about them.

    I'll put his article from Foreign Policy where he talked about this here when I find it.

    NASA is of course hugely obsolete in its internal structure - it's simply too big, with centres all around the country, which causes all kinds of "tribal" politics and a general lack of focus. It squanders a significant portion of its relatively meagre budget on administration and other stuff that had nothing to do with space exploration.

    I can understand the arguments against NASA, but those who use them often fail to understand that without it, there would be no US space programme. The private sector won't just jump in and send a probe to Saturn, because there's no profit in that.
     
  3. Winner

    Winner Diverse in Unity

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    BBC has a nice infographic.

    How big is space?

    Spoiler :






    Also, DARPA leads a study into interstellar (yes, that's right, interstellar) travel - BBC reports.

    Not that I am against it, on the contrary, but I sometimes have a feeling that studies like this get too much press attention and detract from the real effort to step up space exploration. Because let's face it, the idea we'll travel to the stars in 100 years is preposterous, we have barely reached the lunar orbit with a crewed spaceship. No human has ever left Earth's gravitational Sphere of Influence (SOI). We're literally in the same position as a guy who has managed to go to a small barren offshore island and back in a leaky little canoe, but now dreams of circumnavigating the Earth.

    I especially dislike all the people who invoke exotic physics (=magic). No, we won't have any warp drives or stuff like that in this century, or the next, or ever (most likely). So why don't you rather focus on the concepts which could work?
     
  4. CommonKnowledge

    CommonKnowledge Chieftain

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    I haven't seen it linked so far but the ion drive might be a step in that direction.
    Ion drive
    I realise "some day" is incredibly vague but it's already been successfully tested in orbit
     
  5. ghostmaker650

    ghostmaker650 Chieftain

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    Rocket science isn't even that hard :mischief:


    Link to video.

    I've landed on the moon myself, what's the problem NASA?
     
  6. Leifmk

    Leifmk Chieftain

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    Yes, well.

    My Viking-era forefathers weren't necessarily known for being diplomatic in the first place. Iceland was colonized mostly by Norwegians who were unable to get along with the other Norwegians of the time (and if you've read any of the Icelandic sagas you know what kind of a mess they managed to make there, bloodfeuds left and right). Greenland, in turn, was colonized by Icelanders who were too ornery and bloody-minded to make it in Iceland. And then the Vinland colony attempt was made by some guys who were basically being kicked out of Greenland... no wonder they didn't get along with the natives.
     
  7. Thorgalaeg

    Thorgalaeg Warlord

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    And even that is a way too optimistic analogy.
     
  8. Winner

    Winner Diverse in Unity

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    Ion drives (or other forms of electric propulsion - Hall thrusters, magnetoplasmadynamic thrusters, VASIMR, etc.) aren't "exotic physics", they're quite well understood and increasingly used in space probes and Earth-orbiting satellites.

    They offer very high specific impulse (Isp), which is a sort of measure used in rocketry to measure the efficiency of an engine. Basically it tells you how much kick will you get for a given amount of propellant.

    The problem with them is that the thrust is very, very, very low. Comparable to, say, the force of a light breeze you feel on your face during a spring day. For this reason, it takes such engines a long time to accelerate/decelerate a spacecraft. That alone makes them next to useless on manned missions, where we generally want to reduce the trip time as much as possible (because deep space travel is not very healthy).

    The second problem with these engines is that they require quite large amounts of energy to operate, and you have to get it somewhere. The bigger the spacecraft, the bigger the problem. A small electric thruster on a satellite or probe can use the spacecraft's solar panels to get all the juice it needs, but larger spacecraft would require either a very large solar array, or a nuclear reactor with the necessary radiator assemblies and other paraphernalia.

    That is a huge problem - literally. You end up with space battleships weighing thousands of tonnes that can only transport the same amount of payload as a chemical rocket of 1/10th the mass and 1/1000th the complexity.

    Personally, I believe these electric drives will remain a method of propulsion used exclusively on unmanned spacecraft. They could be useful for slow cargo carriers, for example. For human travel we need something else.
     
  9. Winner

    Winner Diverse in Unity

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  10. Leifmk

    Leifmk Chieftain

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    Yeah, their niche is for somewhat slow (as opposed to very slow) long-distance probes, or for station-keeping/orbital adjustments in satellites.
     
  11. LegionSteve

    LegionSteve Motörhead

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    Very interesting thread :goodjob:

    I like the space plane on page 1. If you paint it bright red it would look just like something out of X-Com: Apocalypse. That alone would make it worth investing in as far as I am concerned :)
     
  12. Winner

    Winner Diverse in Unity

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    I think they're still planning to place a VASIMR on the ISS to help compensate for the atmospheric drag.

    It's black because that's the colour of the heat-resistant ceramic compound they want to use for the outer shell. I found an image with a painted SKYLON, I am sure nationalistic Brits will like it:

    Spoiler :


    Also, you can watch the SKYLON animation on YouTube, just search for it.

    What's innovative about this particular spacecraft is the engines, which are basically airbreathing rockets. Since as I said oxygen is the heaviest part of rocket propellant, if you can get it from the atmosphere, you can greatly reduce the mass of the propellant your spaceplane needs to carry in its fuel tanks. SKYLON should reach about Mach 5 in the atmosphere, and then transition to classic rocket mode and fly to the orbit (orbital velocity is about Mach 25, which means SKYLON would achieve about 1/5th of the necessary speed before leaving the atmosphere. It doesn't sound as a lot, but it helps greatly to make the concept of a reusable single-stage-to-orbit spacecraft get off the ground).
     
  13. Crezth

    Crezth 話說天下大勢分久必合合久必分

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    Well, NASA was created in a different time, meant for a different circumstance with different people. It was very exclusive in its inception, and now has grown to be a premiere authority on everything from astronomy, to rocketry, to aeronautics. NASA research labs which are, as you say, littered across the country are not all focused on going to Mars, and in fact many of them have their own specialties and pet projects.

    But this does not decrease their efficacy on a lab-to-lab basis, and between them they are some of the most prolific and useful government labs in the United States today. For all the points about the importance of space exploration being relegated to the back pocket, one can hardly deny the value that NASA provides in research and development, inefficiency notwithstanding.
     
  14. Winner

    Winner Diverse in Unity

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    All right, here is the article I promised. It's from a PDF, so sorry for the quality.

    Tyson makes a very good and clear argument here for why space not only matters, but why it is necessary for the US to maintain the pre-eminent position it now has. All Americans here should definitely read it.

    I especially like his example involving the Hubble space telescope. A software solution for its malfunctioning optics turned out to be really useful in screening for breast cancer - so as a result of our efforts in space exploration, thousands of women are alive today because their breast cancer was found in time to save them.

    Is that concrete enough for all the naysayers? Probably not. But Tyson also explain why space exploration so often leads to such discoveries. It happens because space exploration by definition requires a multi-disciplinary approach, which leads to a "cross-pollination", a useful combination of knowledge and solutions from different disciplines that spur innovation and discovery. If any first world country hopes to maintain its technological lead, heavy investment into space exploration is its best bet.

    Spoiler :
     
  15. Winner

    Winner Diverse in Unity

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    Also, someone plans to recover the F-1 rocket engines that powered the first stage of the Saturn V rocket.

    I think they are still the most powerful single-chamber rocket engines that have ever been built. The Russians have built a more powerful kerosene-oxygen engines for their Zenit booster, but that engine uses a cluster of four chambers (the Russians are simply better at making rocket engines, sorry, Americans).

    The sad thing here is that the US can't even build such engines any more, which is another sign of its regress in technology. Back during the Apollo era, it took just a few years to develop this engine. It was hard as hell, because there were no computers to run simulations on and the engines kept blowing up due to combustion instabilities. But in the end, they were a success.

    Today, NASA is developing an advanced version of an Apollo-era hydrogen-oxygen J-2 engine. It will probably take more than TWO decades and cost enormous amount of money. It's mind boggling how inefficient and unproductive has the US space industry become in the last four decades.

     
  16. Quackers

    Quackers The Frog

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    I for one hope dearly that China releases some kind of top secret memo detailing plans to reach Mars, heh, I think even if they went for the Moon it would spur the US government into long term of funding NASA and setting ambitious goals for them. Mars by mid 2030 is just awful :(, Mars by 2019 imo :D
     
  17. Winner

    Winner Diverse in Unity

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    At present, I think it is really doubtful the US would react to it with any serious determination. Politicians would probably endlessly argue about how to respond, and by the time a bipartisan agreement on sending people to Mars by 2099 would be reached, the Chinese would already have a base there :crazyeye:

    Not that China is going to go to Mars any time soon. They are more interested in the Moon, for obvious reasons. It's the most strategic place in the Earth-Moon system for a nation which has ambitions to challenge the US dominance.
     
  18. Winner

    Winner Diverse in Unity

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    Oh, I almost forgot:

    Orbital freighter arrives to resupply space station



    The third European Automated Transfer Vehicle (ATV) has reached the space station. It carries the heaviest dry cargo load ever transported to the station in a craft other than the Shuttle.
     
  19. IAM

    IAM Chieftain

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    ? hypothetically: you find a rock that is:

    -about the size of a man's fist
    -buried in undisturbed soil about 1 meter deep
    -about 280 meters from the 'obvious' center of a crater in the tragectory path of an impact
    -the crater is one of the many impact areas in the Eastern USA
    -rock does not match soil or rocks in the area (mostly sand with limestone at about 18 meters below ground don't know what's below that)
    -rock about weight of (heavier than any material in the area) but not as heavy as iron
    -found during landscaping excavation (borrow pit area)
    -impact crater area is now flat (shaped like a bowl with a flat bottom) and currently about 220 meters wide by 325 meters long

    how would u identify this object; edit:how would you determine if this really is a meteor?
     
  20. Winner

    Winner Diverse in Unity

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    I am not sure exactly what you're saying about the crater, but

    a) it would be a meteorite. Meteor is the thing you see in the sky.
    b) does the surface of the stone look like it was melted?
    c) the safest bet is to consult an expert. Clean it, make a good photo of it and send it to someone qualified if there is nobody you can show it to in person.

    There are many ways a rock that doesn't fit the geologic background can get to a place (glacier deposits, flooding, someone just dropping it there, etc.). It doesn't necessarily have to be of extraterrestrial origin.
     

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