[HN Gopher] Overview of the New LH2 Sphere at NASA Kennedy Space...
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       Overview of the New LH2 Sphere at NASA Kennedy Space Center [pdf]
        
       Author : perihelions
       Score  : 30 points
       Date   : 2022-09-03 16:25 UTC (6 hours ago)
        
 (HTM) web link (www.energy.gov)
 (TXT) w3m dump (www.energy.gov)
        
       | jeffrallen wrote:
       | Here's a nice factoid from it:
       | 
       | > circa 1970 Accidental production of first glass bubbles at 3M
       | plant in Guin, AL
       | 
       | > circa 1975 Cryogenic research testing by G. R. Cunnington and
       | C. L. Tien at UC Berkeley
        
       | avalys wrote:
       | What's the cost per liter of this tank vs. the one built in the
       | 1960s?
        
       | gardenfelder wrote:
       | All this heavy duty construction at KSC, which is ~10' above
       | present sea level, but then, sea level is rising [1]
       | 
       | [1]
       | https://earthobservatory.nasa.gov/features/NASASeaLevel/page...
        
         | Vecr wrote:
         | They can build earthworks, it's not too bad. It's similar to
         | Manhattan Island for example, unless there's a catastrophic
         | failure of planning and action, they can build a sea wall
         | around it and put storm surge control devices in the rivers.
        
         | jeffrallen wrote:
         | Also: Methalox rockets are proving to be a better choice than
         | hydrogen powered rockets, and while you could store methane in
         | that tank, it's about the most expensive way possible to store
         | methane per litre.
         | 
         | More SLS brain damage.
        
           | semi-extrinsic wrote:
           | Methalox can be a better choice _if you are designing a
           | reusable launch system and you are optimizing for low cost to
           | orbit_.
           | 
           | SLS is planned as an expendable launch system that will put
           | spacecraft far beyond Earth orbit. They need the specific
           | impulse that hydrogen offers.
           | 
           | And in related news, liquid hydrogen is going to become just
           | as mainstream as LNG is today, within a decade from now. All
           | the major LNG ship builders (KHI, GTT etc.) are building and
           | testing LH2 transport ships as we speak. Suiso Frontier began
           | operational sailing more than a year ago.
        
             | dotnet00 wrote:
             | Methalox ends up being preferable because Hydrogen ends up
             | performing relatively similarly when accounting for the
             | extra tank mass needed to effectively contain it (both in
             | terms of thicker walls and larger tanks in general).
             | Methalox can't achieve Hydrogen ISPs but in exchange it's
             | much easier to contain, allowing for much lighter and
             | simpler tanks, resulting in similar deltaV overall.
             | 
             | On top of that cryo methane and oxygen are at closer
             | temperatures than hydrogen and oxygen, which simplifies
             | storage further.
             | 
             | So effectively the difference is that Hydrogen embrittles
             | everything and makes development more expensive even
             | without reuse considerations, making Methane superior
             | unless you're SLS and being wasteful is a feature.
        
             | modeless wrote:
             | Low cost to orbit is the whole ball game. If you have that,
             | everything else is dramatically easier. Not optimizing for
             | that is, as the grandparent comment put it, brain damage.
             | (AKA politics)
        
               | jeffrallen wrote:
               | The private space industry interprets brain damage as
               | damage and routes around it.
        
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       (page generated 2022-09-03 23:00 UTC)