<story><title>Why We Should Build Cloud Cities on Venus</title><url>http://motherboard.vice.com/read/why-we-should-build-cloud-cities-on-venus</url></story><parent_chain><item><author>JulianMorrison</author><text>1g at 1 atmosphere has disadvantages. Namely: to get &lt;i&gt;off&lt;/i&gt; the planet, you will need a fully fuelled multistage rocket with an almost identical profile to rockets you&amp;#x27;d launch from ground level on Earth. Something like a Falcon 9. That&amp;#x27;s a bit heavy to lug all the way from Earth.&lt;p&gt;Bonus: you have to launch by dropping it into a hell-cauldron of poison gases miles above a crushing, melting surface, better hope you don&amp;#x27;t have an engine out, because there are no launch aborts or do-overs. Then you have to fly it out through a hot corrosive acid atmosphere which I don&amp;#x27;t imagine would be very friendly to machined aluminum.</text></item><item><author>aetherson</author><text>In terms of human habitation, the big advantages of Venus&amp;#x27; atmosphere are:&lt;p&gt;1.  It has essentially Earth-normal gravity.  Zero-G long-term is a death sentence for humans.  The long term effects of Martian gravity are unknown.  It seems safe to assume that Venus gravity is fine.&lt;p&gt;2.  It is protected from impact and radiation by an atmosphere in a way that Mars or asteroids never will be.&lt;p&gt;3.  It has an essentially limitless supply of carbon, oxygen, nitrogen, and sulfur available to it.&lt;p&gt;4.  It is reasonably well-positioned for solar power.&lt;p&gt;5.  It is relatively temperate.&lt;p&gt;6.  Low pressure differential between inside a habitat and outside of one means that leaks are less severe and containment breaches are easier to react to.&lt;p&gt;But there is at least one huge disadvantage:&lt;p&gt;1.  Everything besides carbon, oxygen, nitrogen, and sulfur needs to be imported, either from a fantastically hostile surface, or down through reentry into an atmosphere in a deep gravity well and rendezvousing with an aerostat.&lt;p&gt;That disadvantage is a pretty goddamn significant one for human habitation.&lt;p&gt;But it&amp;#x27;s not a disadvantage for long-term robot probes, and it&amp;#x27;s...  less... of a disadvantage for a minimal-population scientific base.</text></item></parent_chain><comment><author>pavel_lishin</author><text>Not quite an identical profile; it&amp;#x27;s not quite 1g, since Venus is less massive, and you&amp;#x27;re already quite a ways off the surface.&lt;p&gt;It&amp;#x27;s still not &lt;i&gt;trivial&lt;/i&gt;, but it&amp;#x27;s not like there are a whole lot of do-overs when launching valuable human cargo from Earth, either. (What happens if the space shuttle&amp;#x27;s engines go awry? Everyone on board dies, and everyone on the ground speculates as to whether they died within 30 seconds, or survived to hit the ocean.)</text></comment>
<story><title>Why We Should Build Cloud Cities on Venus</title><url>http://motherboard.vice.com/read/why-we-should-build-cloud-cities-on-venus</url></story><parent_chain><item><author>JulianMorrison</author><text>1g at 1 atmosphere has disadvantages. Namely: to get &lt;i&gt;off&lt;/i&gt; the planet, you will need a fully fuelled multistage rocket with an almost identical profile to rockets you&amp;#x27;d launch from ground level on Earth. Something like a Falcon 9. That&amp;#x27;s a bit heavy to lug all the way from Earth.&lt;p&gt;Bonus: you have to launch by dropping it into a hell-cauldron of poison gases miles above a crushing, melting surface, better hope you don&amp;#x27;t have an engine out, because there are no launch aborts or do-overs. Then you have to fly it out through a hot corrosive acid atmosphere which I don&amp;#x27;t imagine would be very friendly to machined aluminum.</text></item><item><author>aetherson</author><text>In terms of human habitation, the big advantages of Venus&amp;#x27; atmosphere are:&lt;p&gt;1.  It has essentially Earth-normal gravity.  Zero-G long-term is a death sentence for humans.  The long term effects of Martian gravity are unknown.  It seems safe to assume that Venus gravity is fine.&lt;p&gt;2.  It is protected from impact and radiation by an atmosphere in a way that Mars or asteroids never will be.&lt;p&gt;3.  It has an essentially limitless supply of carbon, oxygen, nitrogen, and sulfur available to it.&lt;p&gt;4.  It is reasonably well-positioned for solar power.&lt;p&gt;5.  It is relatively temperate.&lt;p&gt;6.  Low pressure differential between inside a habitat and outside of one means that leaks are less severe and containment breaches are easier to react to.&lt;p&gt;But there is at least one huge disadvantage:&lt;p&gt;1.  Everything besides carbon, oxygen, nitrogen, and sulfur needs to be imported, either from a fantastically hostile surface, or down through reentry into an atmosphere in a deep gravity well and rendezvousing with an aerostat.&lt;p&gt;That disadvantage is a pretty goddamn significant one for human habitation.&lt;p&gt;But it&amp;#x27;s not a disadvantage for long-term robot probes, and it&amp;#x27;s...  less... of a disadvantage for a minimal-population scientific base.</text></item></parent_chain><comment><author>stcredzero</author><text>&lt;i&gt;&amp;gt; 1g at 1 atmosphere has disadvantages. Namely: to get off the planet, you will need a fully fuelled multistage rocket with an almost identical profile to rockets you&amp;#x27;d launch from ground level on Earth.&lt;/i&gt;&lt;p&gt;Condense Carbon Monoxide and Sulphuric Acid from Venus&amp;#x27;s atmosphere for use as fuel and oxidizer in a hypersonic rocketplane that tops out at about Mach 11. Have the rocketplane rendezvous with the end of a rotating tether.&lt;p&gt;&lt;a href=&quot;http://www.tethers.com/papers/HASTOLAIAAPaper.pdf&quot; rel=&quot;nofollow&quot;&gt;http:&amp;#x2F;&amp;#x2F;www.tethers.com&amp;#x2F;papers&amp;#x2F;HASTOLAIAAPaper.pdf&lt;/a&gt;&lt;p&gt;No multi-stage rocket. No expendable launch vehicles. That&amp;#x27;s probably not the actual solution, but it shows that you don&amp;#x27;t &lt;i&gt;have&lt;/i&gt; to have a Falcon 9 equivalent.&lt;p&gt;&lt;i&gt;&amp;gt; Then you have to fly it out through a hot corrosive acid atmosphere which I don&amp;#x27;t imagine would be very friendly to machined aluminum.&lt;/i&gt;&lt;p&gt;It should be possible to condense HF out of the Venusian atmosphere, so we should be able to manufacture PTFE locally with input from non-Earth resources. (Mining chondrites from Mercury and Venus-crossing asteroids.)</text></comment>