Saturday, August 13, 2011

Morning Summary, 8/13

Good morning.

Yesterday, I did a few posts on SpaceX. I'd like to continue a bit with that here, and perhaps, if I think of it, a little more later on.

The interest in SpaceX dovetails a bit with the last book I read and discussed here this past week. It seems that Elon Musk wants to succeed where NASA failed.

Musk wants his Falcons to be fully re-usable, while the Shuttle was not. It so happens that I wrote a series of posts on re-using the external tank of the Shuttle, and it has occurred to me that this could be a principle that may come in handy, if Musk decides to use it.  Those in charge of policy during the Shuttle era decided not to employ the principle, you see.  That principle, in effect, would be in situ resourcing, with the spent second stage as a resource to be used, rather than discarded.

The Shuttle ET nearly reached orbital velocity.  That's what made the idea of re-using it a possibility.  I am assuming that the second stage of the Falcon nearly reaches orbital velocity.  Because if it does, this may be analogous to the Shuttle ET.  If not, it may not be practical.  If it is the same as the ET, it would take only a nudge to get it up to a stable orbit.  From there, you can find ways to employ the spent stage.  This would only be limited to one's imagination.

If it is not desirable to reuse the spent stage, then it will have to be brought back in such a way as to allow it to be reprocessed and used again for its original purpose.

I've thought about that too.  It would seem that there may be a way to do it if you could design a heat shield that could pop out when you need it for reentry.  You could accelerate it so that it could make one orbit around the Earth, then pop out the shield to keep it from burning up during reentry.  Parachutes could deploy when enough speed has been bled off.  Then splashdown, and recovery of the spent stage.

Or either way could be used, in case you don't want to leave it in space.  Since you are getting it up to orbit anyway, you could keep it there, or have the option to reenter and recover.

That's all on that subject.  I just received another book, which I could be reading today.  If it seems interesting enough to post about, I'll put up some posts on it.

Be good out there, and I'll be checking in later.


With respect to the book, Islands in the Sky: Bold New Ideas for Colonizing Space, wikipedia has an outline of the chapters here.  I'm currently on a chapter about skyhooks and tethers, which I wrote about earlier.

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