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Re: It's not rocket science—we need a better way to get to space

From Sylvia Else <sylvia@not.at.this.address>
Newsgroups sci.physics
Subject Re: It's not rocket science—we need a better way to get to space
Date 2015-11-08 14:01 +1100
Message-ID <da7s83Fo6usU1@mid.individual.net> (permalink)
References (4 earlier) <728s3b18cbu11i1pbvvvbov145367duj2l@4ax.com> <gtidnc7pWbHiuKPLnZ2dnUU7-UMAAAAA@giganews.com> <2j9s3b526963jc5uf62snif8fn8olkgou6@4ax.com> <gtidncnpWbGZuqPLnZ2dnUU7-UOdnZ2d@giganews.com> <n1l98s$nh1$1@speranza.aioe.org>

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On 8/11/2015 3:35 AM, gilber34 wrote:
> On 11/7/2015 10:29 AM, Sam Wormley wrote:
>> On 11/7/15 10:27 AM, Wally W. wrote:
>>> On Sat, 7 Nov 2015 10:23:27 -0600, Sam Wormley wrote:
>>>
>>>> On 11/7/15 10:21 AM, Wally W. wrote:
>>>>> You first.
>>>>
>>>>    No -- Is there anything in following article you would like to
>>>>    discuss with me, Wally?
>>>
>>> What did you find to be most interesting about the article, and why?
>>>
>>
>>    The idea that we need an alternative to rocket -- for economic reasons
>>    to facilitate space travel.  How about you?
>>
>>
>>
>
> the alternatives are less reliable, NASA has demonstrated that.
>
> The more parts, the more failure modes, the lower the reliability.
>
> Reliability is a structured field of enginnering, a body of Math,  and
> NASA has done a calculation to determine the MTTF on all of its vehicles.
>
>

The situation is a bit more complicated than that. One has to go beyond 
the probability of failures, and look at the consequences of them.

If a staged rocket vehicle suffers an in-flight failure, that will 
usually result in the loss of the payload. There's an exception for 
manned flights, because there's provision for re-entry, but the payload 
returned to Earth (the crew) is small. Further, the launch vehicle is 
always lost in such a situation.

By contrast, if you can get your vehicle to return intact to Earth, 
complete with its payload, then you can tolerate a higher in-flight 
failure rate, since the cost of a failure is just the fuel and possibly 
the cost of repositioning.

So in analysing the failures for a reusable vehicle, you have to 
distinguish between failures that destroy the vehicle and payload, and 
those that allow the vehicle and payload to be recovered. Such a 
distinction is not useful for staged non-reusable vehicles.

Airliners are a relevant example - they're complicated machines, and 
things go wrong with them all the time - but the consequences are rarely 
more than a diversion and delay.

Sylvia.


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Thread

It's not rocket science—we need a better way to get to space Sam Wormley <swormley1@gmail.com> - 2015-11-07 08:38 -0600
  Re: It's not rocket science—we need a better way to get to space Poutnik <poutnik4nntp@gmail.com> - 2015-11-07 16:01 +0100
  Re: It's not rocket science—we need a better way to get to space gilber34 <fafa@invalid.com> - 2015-11-07 09:22 -0600
    Re: It's not rocket science—we need a better way to get to space Wally W. <ww84wa@aim.com> - 2015-11-07 10:39 -0500
      Re: It's not rocket science—we need a better way to get to space Edgardo Alcantara <edgardoalcantara@carosseryrepair.org> - 2015-11-07 15:44 +0000
        Re: It's not rocket science—we need a better way to get to space Wally W. <ww84wa@aim.com> - 2015-11-07 11:00 -0500
        Re: It's not rocket science—we need a better way to get to space Fabian Russell <root@localhost.localdomain> - 2015-11-07 21:47 +0000
          Re: It's not rocket science—we need a better way to get to space Edgardo Alcantara <edgardoalcantara@carosseryrepair.org> - 2015-11-08 00:49 +0000
            Re: It's not rocket science—we need a better way to get to space Fabian Russell <root@localhost.localdomain> - 2015-11-08 01:40 +0000
              Re: It's not rocket science?we need a better way to get to space jimp@specsol.spam.sux.com - 2015-11-08 03:27 +0000
                Re: It's not rocket science?we need a better way to get to space Fabian Russell <root@localhost.localdomain> - 2015-11-08 03:43 +0000
                Re: It's not rocket science?we need a better way to get to space jimp@specsol.spam.sux.com - 2015-11-08 04:10 +0000
                Re: It's not rocket science?we need a better way to get to space Fabian Russell <root@localhost.localdomain> - 2015-11-08 04:42 +0000
                Re: It's not rocket science?we need a better way to get to space jimp@specsol.spam.sux.com - 2015-11-08 06:23 +0000
                Re: It's not rocket science?we need a better way to get to space Edgardo Alcantara <edgardoalcantara@carosseryrepair.org> - 2015-11-08 16:01 +0000
                Re: It's not rocket science?we need a better way to get to space jimp@specsol.spam.sux.com - 2015-11-08 17:33 +0000
                Re: It's not rocket science?we need a better way to get to space Ludwig Böhm <ludwb@widespectrum.com> - 2015-11-11 23:56 +0000
                Re: It's not rocket science?we need a better way to get to space jimp@specsol.spam.sux.com - 2015-11-12 00:29 +0000
                Re: It's not rocket science?we need a better way to get to space Ludwig Böhm <ludwb@widespectrum.com> - 2015-11-12 00:38 +0000
                Re: It's not rocket science?we need a better way to get to space jimp@specsol.spam.sux.com - 2015-11-12 01:11 +0000
                Re: It's not rocket science?we need a better way to get to space Ludwig Böhm <ludwb@widespectrum.com> - 2015-11-12 16:07 +0000
                Re: It's not rocket science?we need a better way to get to space jimp@specsol.spam.sux.com - 2015-11-12 18:47 +0000
                Re: It's not rocket science?we need a better way to get to space kefischer <emoneyjoe@iglou.com> - 2015-11-12 16:06 -0500
                Re: It's not rocket science?we need a better way to get to space Ludwig Böhm <ludwb@widespectrum.com> - 2015-11-12 21:22 +0000
                Re: It's not rocket science?we need a better way to get to space Ludwig Böhm <ludwb@widespectrum.com> - 2015-11-12 16:08 +0000
                Re: It's not rocket science?we need a better way to get to space kefischer <emoneyjoe@iglou.com> - 2015-11-11 20:55 -0500
                Re: It's not rocket science?we need a better way to get to space jimp@specsol.spam.sux.com - 2015-11-12 02:09 +0000
                Re: It's not rocket science?we need a better way to get to space kefischer <emoneyjoe@iglou.com> - 2015-11-11 23:08 -0500
                Re: It's not rocket science?we need a better way to get to space jimp@specsol.spam.sux.com - 2015-11-12 04:45 +0000
                Re: It's not rocket science?we need a better way to get to space kefischer <emoneyjoe@iglou.com> - 2015-11-12 03:28 -0500
                Re: It's not rocket science?we need a better way to get to space jimp@specsol.spam.sux.com - 2015-11-12 18:58 +0000
                Re: It's not rocket science?we need a better way to get to space kefischer <emoneyjoe@iglou.com> - 2015-11-12 16:11 -0500
                Re: It's not rocket science?we need a better way to get to space jimp@specsol.spam.sux.com - 2015-11-12 21:43 +0000
              Re: It's not rocket science—we need a better way to get to space kefischer <emoneyjoe@iglou.com> - 2015-11-07 22:53 -0500
                Re: It's not rocket science—we need a better way to get to space Fabian Russell <root@localhost.localdomain> - 2015-11-08 04:14 +0000
                Re: It's not rocket science—we need a better way to get to space kefischer <emoneyjoe@iglou.com> - 2015-11-07 23:43 -0500
                Re: It's not rocket science—we need a better way to get to space Edgardo Alcantara <edgardoalcantara@carosseryrepair.org> - 2015-11-08 16:25 +0000
                Re: It's not rocket science?we need a better way to get to space jimp@specsol.spam.sux.com - 2015-11-08 06:24 +0000
          Re: It's not rocket science?we need a better way to get to space jimp@specsol.spam.sux.com - 2015-11-08 03:29 +0000
            Re: It's not rocket science?we need a better way to get to space Fabian Russell <root@localhost.localdomain> - 2015-11-08 03:40 +0000
              Re: It's not rocket science?we need a better way to get to space jimp@specsol.spam.sux.com - 2015-11-08 04:11 +0000
      Re: It's not rocket science—we need a better way to get to space Sam Wormley <swormley1@gmail.com> - 2015-11-07 09:58 -0600
        Re: It's not rocket science—we need a better way to get to space gilber34 <fafa@invalid.com> - 2015-11-07 10:01 -0600
        Re: It's not rocket science—we need a better way to get to space Wally W. <ww84wa@aim.com> - 2015-11-07 11:21 -0500
          Re: It's not rocket science—we need a better way to get to space Sam Wormley <swormley1@gmail.com> - 2015-11-07 10:23 -0600
            Re: It's not rocket science—we need a better way to get to space Wally W. <ww84wa@aim.com> - 2015-11-07 11:27 -0500
              Re: It's not rocket science—we need a better way to get to space Sam Wormley <swormley1@gmail.com> - 2015-11-07 10:29 -0600
                Re: It's not rocket science—we need a better way to get to space gilber34 <fafa@invalid.com> - 2015-11-07 10:35 -0600
                Re: It's not rocket science—we need a better way to get to space Sylvia Else <sylvia@not.at.this.address> - 2015-11-08 14:01 +1100
        Re: It's not rocket science—we need a better way to get to space jimp@specsol.spam.sux.com - 2015-11-07 18:53 +0000
          Re: It's not rocket science—we need a better way to get to space Sam Wormley <swormley1@gmail.com> - 2015-11-07 14:09 -0600
            Re: It's not rocket science—we need a better way to get to space jimp@specsol.spam.sux.com - 2015-11-07 20:22 +0000
              Re: It's not rocket science—we need a better way to get to space Sam Wormley <swormley1@gmail.com> - 2015-11-07 14:41 -0600
                Re: It's not rocket science—we need a better way to get to space jimp@specsol.spam.sux.com - 2015-11-07 21:19 +0000
            Re: It's not rocket science—we need a better way to get to space Wally W. <ww84wa@aim.com> - 2015-11-07 18:58 -0500
  Re: It's not rocket science--we need a better way to get to space "nuny@bid.nes" <Alien8752@gmail.com> - 2015-11-07 22:27 -0800
    Re: It's not rocket science--we need a better way to get to space Sylvia Else <sylvia@not.at.this.address> - 2015-11-09 16:39 +1100
      Re: It's not rocket science--we need a better way to get to space "nuny@bid.nes" <Alien8752@gmail.com> - 2015-11-09 00:41 -0800
        Re: It's not rocket science--we need a better way to get to space Sylvia Else <sylvia@not.at.this.address> - 2015-11-09 23:16 +1100

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