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    <title><![CDATA[Discussion on Video: Gigantic balloon to lift tourists into space ]]></title>
    <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187]]></link>
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    <lastBuildDate>2013-05-21T09:43:37-07:00</lastBuildDate>
             

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        <title><![CDATA[helium balloon]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-51936]]></link>
        <description><![CDATA[How about using a hot air/helium hybrid balloon? The temperature differenttial would provide good lift. The hot air balloon could be inside a helium balloon. Therefore you would not need to vent the helium.]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-51936]]></guid>
        <dc:creator><![CDATA[kitemanmusic]]></dc:creator>
        <pubDate>Tue, 06 Sep 2011 13:18:05 -0700</pubDate>
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        <title><![CDATA[Sorry, Tuan, your amendment is still wrong!]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50380]]></link>
        <description><![CDATA[Tuan, Your amendment says:  The post was amended to state more accurately that the balloon doesn???t go high enough for passengers to experience the same ???sensation of weightlessness??? caused by microgravity that astronauts feel aboard the International Space Station. Previously, I mistakenly referred to this as zero-G.  Your attempted correction is actually just as misleading as the original because it leaves readers with the impression that gravity really does go down close to zero if the balloon were able to go high enough - e.g. from 22 to 220 miles. Actually the reduction simply due to that change in balloon height (impossible in practice of course!) would be a barely perceptible 9% in body weight.It is not because  &quot;the balloon doesn't go high enough&quot;  that the occupants fail to experience the  &quot;same sensation of weightlessness&quot;  as they would in the ISS. As several of your respondees have already pointed out, the ISS occupants experience weightlessness because of the high angular velocity of the ISS around the earth which causes a centripetal force which  exactly  balances the force due to gravity at that height. In other words, it is in orbit! In comparison, the balloon, of course, has no (significant) angular velocity around the earth so there is nothing to offset the force of gravity however high or low it goes.Incidentally, the so-called &quot;microgravity&quot; experienced in the ISS is nothing to do with some vestige left over of the actual gravity at that height. It is simply a (slightly confusing) scientific term describing the situation in an environment when the actual gravitational force is  exactly balanced by the centripetal force - i.e. it is indeed a condition of true weightlessness.]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50380]]></guid>
        <dc:creator><![CDATA[cosserat@...]]></dc:creator>
        <pubDate>Wed, 24 Aug 2011 06:19:46 -0700</pubDate>
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    <item>
        <title><![CDATA[And at 22 miles up...]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50305]]></link>
        <description><![CDATA[...where do you get this &quot;denser&quot; gas?]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50305]]></guid>
        <dc:creator><![CDATA[JohnMcGrew@...]]></dc:creator>
        <pubDate>Tue, 23 Aug 2011 04:13:42 -0700</pubDate>
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        <title><![CDATA[compressing the gas]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50167]]></link>
        <description><![CDATA[The compressor would have to be no more complicated than a high-speed blower filling another envelope inside the big balloon with denser gas.]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50167]]></guid>
        <dc:creator><![CDATA[buzzbomber1]]></dc:creator>
        <pubDate>Sun, 21 Aug 2011 17:34:11 -0700</pubDate>
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        <title><![CDATA[Will they be squandering inirreplacable helium?]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50166]]></link>
        <description><![CDATA[Helium, being a noble gas, cannot be manufactured; I believe we get it mixed with natural gas. Because it is so light, and leaks escape to space. Since it is so useful for other things, I regard using it for wealthy &quot;tourists&quot; is short sighted and not acceptable.]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50166]]></guid>
        <dc:creator><![CDATA[DougMillar]]></dc:creator>
        <pubDate>Sun, 21 Aug 2011 16:52:08 -0700</pubDate>
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        <title><![CDATA[Equipment Weight]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50162]]></link>
        <description><![CDATA[I thought of that as well and realized that it would increase the requirements for a bigger balloon and more helium but the savings would be realized on multiple trips for none of the helium would be lost.  Sure, it will take more energy to release/compress the helium but I think it would certainly be cost justifiable.]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50162]]></guid>
        <dc:creator><![CDATA[aaron_cutshall@...]]></dc:creator>
        <pubDate>Sat, 20 Aug 2011 09:41:14 -0700</pubDate>
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    <item>
        <title><![CDATA[Actually, Hydrogen is quite renewable...]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50128]]></link>
        <description><![CDATA[...as it's the most common element and practically everywhere.  Balloonists have been extracting it through chemical processes for nearly 200 years.]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50128]]></guid>
        <dc:creator><![CDATA[JohnMcGrew@...]]></dc:creator>
        <pubDate>Fri, 19 Aug 2011 15:02:10 -0700</pubDate>
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        <title><![CDATA[Corrected]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50121]]></link>
        <description><![CDATA[My apologies. I amended the article and made note of the alteration to the article. Thanks!Tuan]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50121]]></guid>
        <dc:creator><![CDATA[tuancnguyen]]></dc:creator>
        <pubDate>Fri, 19 Aug 2011 12:38:12 -0700</pubDate>
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        <title><![CDATA[Balloons and Project Farside]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50104]]></link>
        <description><![CDATA[The USAF used balloons in the late 1950s and 1960s to launch a series of experimental rockets from high above the atmosphere.  They called it Project Farside.  The goal of the program was to place a payload on the far side of the Moon, which goal was never even approached.  http://space.skyrocket.de/doc_lau/farside.htm]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50104]]></guid>
        <dc:creator><![CDATA[rickshaf@...]]></dc:creator>
        <pubDate>Fri, 19 Aug 2011 11:51:51 -0700</pubDate>
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        <title><![CDATA[Thinking About Weightlessness]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50089]]></link>
        <description><![CDATA[Author Nguyen should realize that the altitude at which at which a vehicle finds itself doesn't necessarily determine the state of weightlessness of the occupants.  Even if the &quot;Bloon&quot; COULD somehow rise to the altitude of the ISS, the occupants would NOT be weightless!  Rather, they would feel their full wight, less a tiny amount because they are farther from center of the Earth than they would be at the surface.  Only if the vehicle somehow achieved orbital velocity would the acceleration due to its being in a circular orbit offset the occupants' weight.]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50089]]></guid>
        <dc:creator><![CDATA[rickshaf@...]]></dc:creator>
        <pubDate>Fri, 19 Aug 2011 11:51:19 -0700</pubDate>
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    <item>
        <title><![CDATA[$156,000 dollars?]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50102]]></link>
        <description><![CDATA[First of all $156,000 dollars reads &quot;one hundred fifty six thousand dollars dollars&quot;, but aside from that, doesn't Richard Branson plan to offer sub-orbital flights for about the same price?  I guess the Bloon would be for the less adventurous (much more relaxing), but I think for the money, I'd rather go higher and get my wings!]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50102]]></guid>
        <dc:creator><![CDATA[omb00900@...]]></dc:creator>
        <pubDate>Fri, 19 Aug 2011 11:26:35 -0700</pubDate>
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    <item>
        <title><![CDATA[Surfing?]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50098]]></link>
        <description><![CDATA[Why does the ballon jump video end with surfing footage?]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50098]]></guid>
        <dc:creator><![CDATA[omb00900@...]]></dc:creator>
        <pubDate>Fri, 19 Aug 2011 11:20:43 -0700</pubDate>
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        <title><![CDATA[They could use hydrogen]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50096]]></link>
        <description><![CDATA[Hydrogen is also a non-renewable resource, but we have oceans of it.  And, hydrogen gas is half the mass of helium gas.  (Not 1/4th.  Hydrogen gas is diatomic; helium isn't.)  Another benefit of hydrogen is that occasionally we'll get a spectacular disaster that kills off a dozen mega-rich people.]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50096]]></guid>
        <dc:creator><![CDATA[dmm99]]></dc:creator>
        <pubDate>Fri, 19 Aug 2011 11:03:36 -0700</pubDate>
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    <item>
        <title><![CDATA[Thanks!]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50094]]></link>
        <description><![CDATA[Thanks for saying what I was thinking.  People just don't realize that if the ISS didn't have a &quot;forward motion&quot; of 17,000 MPH, it would fall like a stone (OK, technically, it IS falling like a stone!).  Didn't the author take Physics 101?  It's Newton!  You just don't get more basic than that!  How much do you weigh 220 miles above the Earth's surface?  About the same as you do here on the ground!]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50094]]></guid>
        <dc:creator><![CDATA[omb00900@...]]></dc:creator>
        <pubDate>Fri, 19 Aug 2011 10:55:25 -0700</pubDate>
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    <item>
        <title><![CDATA[GET RID OF ALL THESE CRIMINALS ON EARTH]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50087]]></link>
        <description><![CDATA[I HOPE THAT ONE DAY THE GOVERNMENT CAN SEND ALL THESE CRIMINALS TO ANOTHER PLANET. I HAD IT WITH CRIME ON THIS PLANET. PEOPLE ARE LIVING IN FEAR EVERYWHERE.]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50087]]></guid>
        <dc:creator><![CDATA[edwin1234]]></dc:creator>
        <pubDate>Fri, 19 Aug 2011 10:53:10 -0700</pubDate>
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        <title><![CDATA[helium]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50093]]></link>
        <description><![CDATA[I see no reason why the balloon cannot have its helium compressed on board to lower its bouyancy rather than venting it other than the loss of perhaps one passenger's weight. a small compressor run on lithium batteries ought to make this possible..and thus the principle of baloon flight can be made &quot;green&quot; and recyclable.]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50093]]></guid>
        <dc:creator><![CDATA[nfiertel]]></dc:creator>
        <pubDate>Fri, 19 Aug 2011 10:50:58 -0700</pubDate>
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    <item>
        <title><![CDATA[Running out of helium!]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50082]]></link>
        <description><![CDATA[In 25 years?  Oh my gosh, how will I make a squeaky voice at my grandchild's birthday party?BTW, nothing is ever said about weightlessness in this article.  You don't achieve weightlessness, even in the ISS, unless you are perpetually falling toward earth.  If the ISS held perfectly steady above the earth the astronauts would still experience gravity.  Think about it... the mere fact that the ISS and other satellites are orbiting the earth means that they are experiencing gravity.]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50082]]></guid>
        <dc:creator><![CDATA[boomchuck1]]></dc:creator>
        <pubDate>Fri, 19 Aug 2011 09:43:38 -0700</pubDate>
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        <title><![CDATA[Compression]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50056]]></link>
        <description><![CDATA[That's precisely what I wondered when I read the story. Don't vent; compress. Maybe it's a question of the quantities involved and the amount of equipment to compress the gas in a reasonable time. Hmm.]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50056]]></guid>
        <dc:creator><![CDATA[charley cross]]></dc:creator>
        <pubDate>Fri, 19 Aug 2011 09:00:14 -0700</pubDate>
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        <title><![CDATA[Probably because of weight.]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50064]]></link>
        <description><![CDATA[Recompressing that much Helium would require a sizable compression unit, the fuel to run it, and, of course, high-pressure tanks to hold it all.  The weight of all of that would likely be a ton or more, meaning the vehicle would barely be able to get off the ground, much less anywhere near the edge of space.]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50064]]></guid>
        <dc:creator><![CDATA[JohnMcGrew@...]]></dc:creator>
        <pubDate>Fri, 19 Aug 2011 08:56:52 -0700</pubDate>
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        <title><![CDATA[Oh good, it's &amp;quot;carbon free&amp;quot;...]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50078]]></link>
        <description><![CDATA[...which I guess is the standard by which we now morally judge any industrial or recreational activity.  (But then again, by that standard so was the Space Shuttle, for the most part, as its engines were fueled by hydrogen)  Never mind the infrastructure required to launch and retrieve the vehicle, or the massive use of non-renewable Helium.Not that I wish to be so critical of this venture.  Actually, I think it looks pretty cool.  But if you're going to throw the &quot;carbon footprint&quot; argument in as a justification, then that's the framework you have to be willing to be criticised under.Also, achieving &quot;zero-g&quot; is not a function of altitude, but velocity.  Once must acquire either a 9.8m/sec vertical deceleration, orbital (horizontal) velocity (dependent upon altitude) or some combination thereof.]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-7187-50078]]></guid>
        <dc:creator><![CDATA[JohnMcGrew@...]]></dc:creator>
        <pubDate>Fri, 19 Aug 2011 08:52:32 -0700</pubDate>
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