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

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  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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#531125 — Re: It's not rocket science?we need a better way to get to space

In sci.physics Fabian Russell <root@localhost.localdomain> wrote:
> On Sun, 08 Nov 2015 03:29:15 +0000, jimp wrote:
> 
>>> 
>>> The main reason for staging has to with trajectories.
>> 
>> Nope, it is the fuel load required to reach orbit.
>> 
> 
> It's really just a different way of looking at the same thing.

Nope.

> The staging does correspond to those points where burns are executed
> specifically to attain an orbital trajectory.

Based on the fuel the stages carry.
 

-- 
Jim Pennino

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#530908

On 11/7/15 9:39 AM, Wally W. wrote:
> https://en.wikipedia.org/wiki/Multistage_rocket
> The main reason for multi-stage rockets and boosters is that once the
> fuel is exhausted, the space and structure which contained it and the
> motors themselves are useless and only add weight to the vehicle which
> slows down its future acceleration.
> ...
> This means that it needs less total fuel to reach a given velocity
> and/or altitude.
>

   What did you think about the following article:

   It's not rocket science—we need a better way to get to space
 > http://phys.org/news/2015-11-rocket-sciencewe-space.html

 > The SKYLON project relies on the development of its SABRE engine. The
 > unique engine functions as either a plane engine or a rocket engine.
 > The vehicle can take off from a runway like a plane (efficient) and
 > fly as high and as fast as possible. Then the SKYLON plane switches
 > its engines into rocket mode for the rest of its journey.
 >
 > The design shows enough promise that the European Space Agency and
 > the UK Space Agency both recently invested in the concept. The
 > company claims test flights could happen by 2019.
 >
 > Being more efficient means that it is possible to get all of your
 > spacecraft and some cargo to orbit and back without having to
 > jettison anything along the way. Being able to land the whole vehicle
 > means you can use it again, allowing you to spread the cost of
 > building it over many flights, just like a plane.
 >


-- 

sci.physics is an unmoderated newsgroup dedicated
to the discussion of physics, news from the physics
community, and physics-related social issues.

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#530911

On 11/7/2015 9:58 AM, Sam Wormley wrote:
> On 11/7/15 9:39 AM, Wally W. wrote:
>> https://en.wikipedia.org/wiki/Multistage_rocket
>> The main reason for multi-stage rockets and boosters is that once the
>> fuel is exhausted, the space and structure which contained it and the
>> motors themselves are useless and only add weight to the vehicle which
>> slows down its future acceleration.
>> ...
>> This means that it needs less total fuel to reach a given velocity
>> and/or altitude.
>>

>  > Being more efficient means that it is possible to get all of your
>  > spacecraft and some cargo to orbit and back without having to
>  > jettison anything along the way. Being able to land the whole vehicle
>  > means you can use it again, allowing you to spread the cost of
>  > building it over many flights, just like a plane.
>  >
>
>

NASA disagrees with you.

  the plane configuration is shown to be unsafe with the multiple 
catrosphic manned failures of NASA airplane like spacecraft.

Rockets are simpler, more reliable, faster, less complicated.

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#530913 — Re: It's not rocket science—we need a better way to get to space

On Sat, 7 Nov 2015 09:58:28 -0600, Sam Wormley wrote:

>On 11/7/15 9:39 AM, Wally W. wrote:
>> https://en.wikipedia.org/wiki/Multistage_rocket
>> The main reason for multi-stage rockets and boosters is that once the
>> fuel is exhausted, the space and structure which contained it and the
>> motors themselves are useless and only add weight to the vehicle which
>> slows down its future acceleration.
>> ...
>> This means that it needs less total fuel to reach a given velocity
>> and/or altitude.
>>
>
>   What did you think about the following article:

You first.

What did you think of it? 

If you want a discussion, then discuss.

Otherwise, you are just trolling.

https://en.wikipedia.org/wiki/Internet_troll
the 2014 study suggested that the noxious personality characteristics
known as the "dark triad of personality" should be investigated in the
analysis of trolling, and concluded that trolling appears "to be an
Internet manifestation of everyday sadism."

I am more interested in your take on the post in another of the
numerous threads you start and abandon:

Date: Fri, 6 Nov 2015 13:26:12 -0800 (PST)
Subject: Re: Technology's role in a climate solution
From: Puppet_Sock <puppet_sock@hotmail.com>
Message-ID: <a5722a96-87ea-4d35-b815-63e2e542ae6a@googlegroups.com>

:> The warmistas are not just wrong. They are festeringly evil.
:> They are giggling malevolent monsters, perching and waiting
:> to feast on the bodies of the people, by the billion, they
:> hope to kill.

I think he is spot on.

Do you disagree? If so, why?

It could make a good poster for distribution outside the meetings in
Paris. Don't you agree?

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#530916

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?

   It's not rocket science—we need a better way to get to space
 > http://phys.org/news/2015-11-rocket-sciencewe-space.html

 > The SKYLON project relies on the development of its SABRE engine. The
 > unique engine functions as either a plane engine or a rocket engine.
 > The vehicle can take off from a runway like a plane (efficient) and
 > fly as high and as fast as possible. Then the SKYLON plane switches
 > its engines into rocket mode for the rest of its journey.
 >
 > The design shows enough promise that the European Space Agency and
 > the UK Space Agency both recently invested in the concept. The
 > company claims test flights could happen by 2019.
 >
 > Being more efficient means that it is possible to get all of your
 > spacecraft and some cargo to orbit and back without having to
 > jettison anything along the way. Being able to land the whole vehicle
 > means you can use it again, allowing you to spread the cost of
 > building it over many flights, just like a plane.
 >





-- 

sci.physics is an unmoderated newsgroup dedicated
to the discussion of physics, news from the physics
community, and physics-related social issues.

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#530918 — Re: It's not rocket science—we need a better way to get to space

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?

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#530920

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?



-- 

sci.physics is an unmoderated newsgroup dedicated
to the discussion of physics, news from the physics
community, and physics-related social issues.

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#530922

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.

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#531108

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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#530963

Sam Wormley <swormley1@gmail.com> wrote:
> On 11/7/15 9:39 AM, Wally W. wrote:
>> https://en.wikipedia.org/wiki/Multistage_rocket
>> The main reason for multi-stage rockets and boosters is that once the
>> fuel is exhausted, the space and structure which contained it and the
>> motors themselves are useless and only add weight to the vehicle which
>> slows down its future acceleration.
>> ...
>> This means that it needs less total fuel to reach a given velocity
>> and/or altitude.
>>
> 
>   What did you think about the following article:

You mean the one you repasted several times, spamming shit head?

First it is childisly simplistic.

It overlooks the fact that you HAVE to have a fuel tank large enough
to get into space, which once you are in space is dead weight.

Simply look at the size of the boosters and fuel tanks that were
needed to get the shuttle into space compared to the size of the shuttle.


-- 
Jim Pennino

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#530987

On 11/7/15 12:53 PM, jimp@specsol.spam.sux.com wrote:
> You mean the one you repasted several times, spamming shit head?


   Now, now, jimp, you're slipping again, your language inappropriate,
   and your absolute contempt and total disgust are addressed in these
   Anger Management classes. You, jimp, need these services:
 > http://yellowpages.com/rancho-cucamonga-ca/anger-management-classes


   It's not rocket science—we need a better way to get to space
 > http://phys.org/news/2015-11-rocket-sciencewe-space.html

 > The SKYLON project relies on the development of its SABRE engine. The
 > unique engine functions as either a plane engine or a rocket engine.
 > The vehicle can take off from a runway like a plane (efficient) and
 > fly as high and as fast as possible. Then the SKYLON plane switches
 > its engines into rocket mode for the rest of its journey.
 >
 > The design shows enough promise that the European Space Agency and
 > the UK Space Agency both recently invested in the concept. The
 > company claims test flights could happen by 2019.
 >
 > Being more efficient means that it is possible to get all of your
 > spacecraft and some cargo to orbit and back without having to
 > jettison anything along the way. Being able to land the whole vehicle
 > means you can use it again, allowing you to spread the cost of
 > building it over many flights, just like a plane.
 >


-- 

sci.physics is an unmoderated newsgroup dedicated
to the discussion of physics, news from the physics
community, and physics-related social issues.

[toc] | [prev] | [next] | [standalone]

#531001

Sam Wormley <swormley1@gmail.com> wrote:
> On 11/7/15 12:53 PM, jimp@specsol.spam.sux.com wrote:
>> You mean the one you repasted several times, spamming shit head?
> 
> 
>   Now, now, jimp,

Now, now, spamming piece of cut and paste shit, where is your discussion
of the points I raised, or is repeated cut and pasting of the same
thing over and over again all your tiny little mind is capable of?


-- 
Jim Pennino

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#531005

On 11/7/15 2:22 PM, jimp@specsol.spam.sux.com wrote:
> Now, now, spamming piece of cut and paste shit, where is your discussion
> of the points I raised, or is repeated cut and pasting of the same
> thing over and over again all your tiny little mind is capable of?



   Now, now, jimp, you're slipping again, your language inappropriate,
   and your absolute contempt and total disgust are addressed in these
   Anger Management classes. You, jimp, need these services:
 > http://yellowpages.com/rancho-cucamonga-ca/anger-management-classes


   It's not rocket science—we need a better way to get to space
 > http://phys.org/news/2015-11-rocket-sciencewe-space.html

 > The SKYLON project relies on the development of its SABRE engine. The
 > unique engine functions as either a plane engine or a rocket engine.
 > The vehicle can take off from a runway like a plane (efficient) and
 > fly as high and as fast as possible. Then the SKYLON plane switches
 > its engines into rocket mode for the rest of its journey.
 >
 > The design shows enough promise that the European Space Agency and
 > the UK Space Agency both recently invested in the concept. The
 > company claims test flights could happen by 2019.
 >
 > Being more efficient means that it is possible to get all of your
 > spacecraft and some cargo to orbit and back without having to
 > jettison anything along the way. Being able to land the whole vehicle
 > means you can use it again, allowing you to spread the cost of
 > building it over many flights, just like a plane.
 >


-- 

sci.physics is an unmoderated newsgroup dedicated
to the discussion of physics, news from the physics
community, and physics-related social issues.

[toc] | [prev] | [next] | [standalone]

#531022

Sam Wormley <swormley1@gmail.com> wrote:
> On 11/7/15 2:22 PM, jimp@specsol.spam.sux.com wrote:
>> Now, now, spamming piece of cut and paste shit, where is your discussion
>> of the points I raised, or is repeated cut and pasting of the same
>> thing over and over again all your tiny little mind is capable of?
> 
> 
> 
>   Now, now, jimp,

Now, now, spamming piece of cut and paste shit, I see once again you
are incapapble of addressing my point.


-- 
Jim Pennino

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#531060 — Re: It's not rocket science—we need a better way to get to space

On Sat, 7 Nov 2015 14:09:35 -0600, Sam Wormley wrote:

>On 11/7/15 12:53 PM, jimp@specsol.spam.sux.com wrote:
>> You mean the one you repasted several times, spamming shit head?
>
>
>   Now, now, jimp, you're slipping again, your language inappropriate,

What language would be appropriate?

Are you expecting some form of thanks for trolling?

Do you receive payment for your spew here?

If so, maybe you could copy and paste your COI statement.

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#531139 — Re: It's not rocket science--we need a better way to get to space

On Saturday, November 7, 2015 at 6:38:47 AM UTC-8, Sam Wormley wrote:
> It's not rocket science--we need a better way to get to space
> > http://phys.org/news/2015-11-rocket-sciencewe-space.html
> 
>    Rockets are a terrible way of getting to space.

(nothing-new article snippet snipped)

  To paraphrase Churchill:

  "It has been said that rocketry is the worst way to get to space except all the others that have been tried."

  Not all that many "other ways" have actually been tried, but conceptually, they've been pretty well explored. I don't just mean in research labs, either.

  In some science fiction, actual scientists have been known to field thought experiments they can't propose among other scientists about the kinds of engineering that often descends from the sciences. Science fiction has depicted many other ways of getting to space; some feasible, some possible but infeasible (for various reasons) and some completely impossible.

  Multifunctional engines (turbojets that switch to various supersonic modes and or to pure rocket) are old hat in SF but are very hard to implement in real life, and are not likely to provide the benefits usually claimed- not because of unreliability, but because no multipurpose tool can be as efficient in any one of its functions as a purpose-specific tool. In other words, the Skylon system can not be as efficient as a standard airbreather in that phase of its operation as an ordinary, optimized turbojet, nor can it in its other modes (ignoring for the moment that hypersonic jets are not exactly mature enough tech to determine their efficiency or reliability). There's also that pesky issue of having to accelerate and decelerate empty fuel tanks for much of a given flight.

  Putting to the side for the moment those SFnal ways currently thought to be flat-out impossible (e. g. antigravity, teleportation) we are left with things like Bull's so-called space cannon, beanstalks, and similar "flights of fancy".

  The space cannon idea is indeed feasible for some kinds of payloads, but the launch acceleration is guaranteed to kill anything living. Beanstalks are very low-energy launch methods- you basically ride an elevator to orbit and go from there, but they will be horribly expensive and have many inherent failure modes, not to mention being extremely susceptible to sabotage.

  The real problem is the sheer amount of energy you need to get a given mass into orbit. As far as I know, there's only one really energy-intensive power source available, and that's nuclear-powered systems.

  The original Project Orion

https://en.wikipedia.org/wiki/Project_Orion_%28nuclear_propulsion%29

  ...offered high thrust-per-mass and high specific impulse, two very desirable targets in rocket design. However, various "test ban" treaties effectively killed it (to nobody's surprise).

  Nuclear steam rocketry, much more efficient than chemical rocketry, has been explored on paper and prototypes have been built and tested but never used because of concerns about catastrophic failures dumping the reactor fuel into the environment:

https://en.wikipedia.org/wiki/Nuclear_thermal_rocket

  There was one interesting "zero-stage-to-orbit" idea fielded in the 1960's- you basically take a standard underground nuclear test setup and fill the hole you used to place the bomb with water, and park your payload on top of that. The nuke explosion turns the water to steam, which expands not so violently as to squish the payload. All fallout is contained and the payload suffers no radiation. It was estimated that any of the tests that pockmarked Nevada in the 60's could have put payloads in the low dozens of *tons* into stable orbit.

  I can't remember the name of the study, nor can I find a link right now. The idea is certainly mechanically feasible, but currently politically impossible.

  The current speculative darling, the "reactionless" EM thruster, even if it's a real thing, needs a huge efficiency boost before it's ready to propel small unmanned spacecraft, much less be usable as a heavy launcher.

  Single-stage-to-orbit is a pipe dream without sufficient motivation to overcome, or ignore, current political and technological hurdles.

  In other words, we have to want it badly enough to give some of the known, but unused, methods their chance.

  What motivations might do that for us, Sam?


  Mark L. Fergerson

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#531347 — Re: It's not rocket science--we need a better way to get to space

On 8/11/2015 5:27 PM, nuny@bid.nes wrote:
> On Saturday, November 7, 2015 at 6:38:47 AM UTC-8, Sam Wormley
> wrote:
>> It's not rocket science--we need a better way to get to space
>>> http://phys.org/news/2015-11-rocket-sciencewe-space.html
>>
>> Rockets are a terrible way of getting to space.
>
> (nothing-new article snippet snipped)
>
> To paraphrase Churchill:
>
> "It has been said that rocketry is the worst way to get to space
> except all the others that have been tried."
>
> Not all that many "other ways" have actually been tried, but
> conceptually, they've been pretty well explored. I don't just mean in
> research labs, either.
>
> In some science fiction, actual scientists have been known to field
> thought experiments they can't propose among other scientists about
> the kinds of engineering that often descends from the sciences.
> Science fiction has depicted many other ways of getting to space;
> some feasible, some possible but infeasible (for various reasons) and
> some completely impossible.
>
> Multifunctional engines (turbojets that switch to various supersonic
> modes and or to pure rocket) are old hat in SF but are very hard to
> implement in real life, and are not likely to provide the benefits
> usually claimed- not because of unreliability, but because no
> multipurpose tool can be as efficient in any one of its functions as
> a purpose-specific tool. In other words, the Skylon system can not be
> as efficient as a standard airbreather in that phase of its operation
> as an ordinary, optimized turbojet, nor can it in its other modes
> (ignoring for the moment that hypersonic jets are not exactly mature
> enough tech to determine their efficiency or reliability). There's
> also that pesky issue of having to accelerate and decelerate empty
> fuel tanks for much of a given flight.

It's worth noting that the Sabre engine does not function as a turbo jet 
(or ramjet) at any stage of its operation. Propulsion is achieved by 
means of rockets throughout. During the air breathing phase, the rockets 
receive hydrogen from the tanks, and oxygen (and nitrogen) from the air. 
In non air-breathing mode the rockets receives all their propellants 
from the tanks.

As for having to accelerate the tanks, that reduces the payload 
fraction, but you get the tanks back intact. So you need a larger 
vehicle for a given payload, but you don't have to keep rebuilding it. 
One needs to do the sums before one can form a view about whether that's 
worthwhile.

Sylvia.

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#531358 — Re: It's not rocket science--we need a better way to get to space

On Sunday, November 8, 2015 at 9:39:38 PM UTC-8, Sylvia Else wrote:
> On 8/11/2015 5:27 PM, nuny@bid.nes wrote:
> > On Saturday, November 7, 2015 at 6:38:47 AM UTC-8, Sam Wormley
> > wrote:
> >> It's not rocket science--we need a better way to get to space
> >>> http://phys.org/news/2015-11-rocket-sciencewe-space.html
> >>
> >> Rockets are a terrible way of getting to space.
> >
> > (nothing-new article snippet snipped)
> >
> > To paraphrase Churchill:
> >
> > "It has been said that rocketry is the worst way to get to space
> > except all the others that have been tried."

(snip)

> > Multifunctional engines (turbojets that switch to various supersonic
> > modes and or to pure rocket) are old hat in SF but are very hard to
> > implement in real life, and are not likely to provide the benefits
> > usually claimed- not because of unreliability, but because no
> > multipurpose tool can be as efficient in any one of its functions as
> > a purpose-specific tool. In other words, the Skylon system can not be
> > as efficient as a standard airbreather in that phase of its operation
> > as an ordinary, optimized turbojet, nor can it in its other modes
> > (ignoring for the moment that hypersonic jets are not exactly mature
> > enough tech to determine their efficiency or reliability). There's
> > also that pesky issue of having to accelerate and decelerate empty
> > fuel tanks for much of a given flight.
> 
> It's worth noting that the Sabre engine does not function as a turbo jet 
> (or ramjet) at any stage of its operation. Propulsion is achieved by 
> means of rockets throughout. During the air breathing phase, the rockets 
> receive hydrogen from the tanks, and oxygen (and nitrogen) from the air. 
> In non air-breathing mode the rockets receives all their propellants 
> from the tanks.

  That's sort of correct but handwaves away some subtleties. The precooler is the first of a series of tradeoffs in the Sabre engine- it has to bypass some (very hot) air which incurs a drag penalty. Another is that the precooler needs lots more LH2 (to accept heat from the airstream via the helium loop) per second than the combustion chamber needs, meaning some LH2 has to be dumped overboard which wastes its fuel value. Instead, the dumped no-longer-L H2 is cleverly burned with the bypass air in ramjets that ring the rocket nozzle, producing thrust intended to offset most of the initial drag penalty. This is a really neat way to combine tradeoffs productively, but it's a stack of delicate balances.

  [Claiming the Sabre is a rocket in all modes of operation seems to me to be disingenuous (yes, I know, the claim didn't originate with you). Just because the incoming air compressor is not driven by a power turbine in the exhaust stream doesn't, to me, disqualify the Sabre as a form of "turbojet". And, doesn't "air breathing rocket" strike anyone else as an oxymoron? The Sabre straddles two conventional pigeonholes in airbreathing mode but still has a foot firmly in each. I'm more comfortable calling it a hybrid but perhaps that's just old-fogey-ism on my part.]

> As for having to accelerate the tanks, that reduces the payload 
> fraction, but you get the tanks back intact. So you need a larger 
> vehicle for a given payload, but you don't have to keep rebuilding it. 
> One needs to do the sums before one can form a view about whether that's 
> worthwhile.

  That comes under "specific impulse", aka thrust-to-weight ratio. The larger that is, the more non-reactant mass you can afford to carry around. The Sabre's is *designed* to be in double digits, and if testing confirms the design goals it will be worthwhile, as you put it, but the pudding isn't done yet.

  I'm not against new ideas that advance the art, or to multimode machines in general (I specifically dislike single-purpose tools even if they're the best at their task). The (IMNSHO) most beautiful manmade thing ever to fly, the SR-71, flew on engines that (mostly) smoothly transitioned from pure turbojet to pure ramjet modes, a technological miracle for its time, giving it a still-unequaled flight envelope. Even so, for its entire operational lifetime it was actively juggling a series of tradeoffs giving it a reputation for temperament, "unstarting" in ramjet mode at inconvenient moments for no apparent reason. That's bad enough in level flight at Mach 3 or so at 80,000 ft with no payload on the line- boosting through that altitude at Mach 5 with passengers aboard... let's just say I want the pudding to consistently earn five stars before I'd get aboard.

  The SR-71 reminds me of another subtlety influencing engine, and overall aircraft, efficiency, namely how the airframe shape affects airflow into and past the engine(s). Most of the renderings for concept planes using the Sabre look, well, less than optimal to me. That's a somewhat different area of physics though.


  Mark L. Fergerson

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#531366 — Re: It's not rocket science--we need a better way to get to space

On 9/11/2015 7:41 PM, nuny@bid.nes wrote:
> On Sunday, November 8, 2015 at 9:39:38 PM UTC-8, Sylvia Else wrote:
>> On 8/11/2015 5:27 PM, nuny@bid.nes wrote:
>>> On Saturday, November 7, 2015 at 6:38:47 AM UTC-8, Sam Wormley
>>> wrote:
>>>> It's not rocket science--we need a better way to get to space
>>>>> http://phys.org/news/2015-11-rocket-sciencewe-space.html
>>>>
>>>> Rockets are a terrible way of getting to space.
>>>
>>> (nothing-new article snippet snipped)
>>>
>>> To paraphrase Churchill:
>>>
>>> "It has been said that rocketry is the worst way to get to space
>>> except all the others that have been tried."
>
> (snip)
>
>>> Multifunctional engines (turbojets that switch to various
>>> supersonic modes and or to pure rocket) are old hat in SF but are
>>> very hard to implement in real life, and are not likely to
>>> provide the benefits usually claimed- not because of
>>> unreliability, but because no multipurpose tool can be as
>>> efficient in any one of its functions as a purpose-specific tool.
>>> In other words, the Skylon system can not be as efficient as a
>>> standard airbreather in that phase of its operation as an
>>> ordinary, optimized turbojet, nor can it in its other modes
>>> (ignoring for the moment that hypersonic jets are not exactly
>>> mature enough tech to determine their efficiency or reliability).
>>> There's also that pesky issue of having to accelerate and
>>> decelerate empty fuel tanks for much of a given flight.
>>
>> It's worth noting that the Sabre engine does not function as a
>> turbo jet (or ramjet) at any stage of its operation. Propulsion is
>> achieved by means of rockets throughout. During the air breathing
>> phase, the rockets receive hydrogen from the tanks, and oxygen (and
>> nitrogen) from the air. In non air-breathing mode the rockets
>> receives all their propellants from the tanks.
>
> That's sort of correct but handwaves away some subtleties. The
> precooler is the first of a series of tradeoffs in the Sabre engine-
> it has to bypass some (very hot) air which incurs a drag penalty.
> Another is that the precooler needs lots more LH2 (to accept heat
> from the airstream via the helium loop) per second than the
> combustion chamber needs, meaning some LH2 has to be dumped overboard
> which wastes its fuel value. Instead, the dumped no-longer-L H2 is
> cleverly burned with the bypass air in ramjets that ring the rocket
> nozzle, producing thrust intended to offset most of the initial drag
> penalty. This is a really neat way to combine tradeoffs productively,
> but it's a stack of delicate balances.
>
> [Claiming the Sabre is a rocket in all modes of operation seems to me
> to be disingenuous (yes, I know, the claim didn't originate with
> you). Just because the incoming air compressor is not driven by a
> power turbine in the exhaust stream doesn't, to me, disqualify the
> Sabre as a form of "turbojet". And, doesn't "air breathing rocket"
> strike anyone else as an oxymoron? The Sabre straddles two
> conventional pigeonholes in airbreathing mode but still has a foot
> firmly in each. I'm more comfortable calling it a hybrid but perhaps
> that's just old-fogey-ism on my part.]

The essence of a jet - be it turbojet, ramjet, or scramjet, is that the 
fuel is burnt in a hot and moving air stream. Yet that is nothing like 
the way the Sabre engine works. The captured air enters the combustion 
chamber while it is very dense and very cold. It's not actually liquid, 
but not far from it. It is also moving slowly, or at least, at a speed 
comparable to that of the hydrogen. The design of the combustion chamber 
and nozzle have every similarity to that of a rocket engine, and nothing 
at all resembling a jet.

Of course, we needn't get into an argument about the meaning of words, 
but the reasoning about its inevitable inefficiency due to its hybrid 
nature just doesn't work. That's not to say that the conclusion is 
necessarily wrong, but if it is, it must be reached by a different line 
of argument.

>
>> As for having to accelerate the tanks, that reduces the payload
>> fraction, but you get the tanks back intact. So you need a larger
>> vehicle for a given payload, but you don't have to keep rebuilding
>> it. One needs to do the sums before one can form a view about
>> whether that's worthwhile.
>
> That comes under "specific impulse", aka thrust-to-weight ratio. The
> larger that is, the more non-reactant mass you can afford to carry
> around. The Sabre's is *designed* to be in double digits, and if
> testing confirms the design goals it will be worthwhile, as you put
> it, but the pudding isn't done yet.
>
> I'm not against new ideas that advance the art, or to multimode
> machines in general (I specifically dislike single-purpose tools even
> if they're the best at their task). The (IMNSHO) most beautiful
> manmade thing ever to fly, the SR-71, flew on engines that (mostly)
> smoothly transitioned from pure turbojet to pure ramjet modes, a
> technological miracle for its time, giving it a still-unequaled
> flight envelope. Even so, for its entire operational lifetime it was
> actively juggling a series of tradeoffs giving it a reputation for
> temperament, "unstarting" in ramjet mode at inconvenient moments for
> no apparent reason. That's bad enough in level flight at Mach 3 or so
> at 80,000 ft with no payload on the line- boosting through that
> altitude at Mach 5 with passengers aboard... let's just say I want
> the pudding to consistently earn five stars before I'd get aboard.
>
> The SR-71 reminds me of another subtlety influencing engine, and
> overall aircraft, efficiency, namely how the airframe shape affects
> airflow into and past the engine(s). Most of the renderings for
> concept planes using the Sabre look, well, less than optimal to me.
> That's a somewhat different area of physics though.

Not sure what your objections are there. The engines have to be mounted 
where they are to maintain the centre of gravity as the propellants are 
consumed. They also have to far enough from the nose, and sufficiently 
inboard that the nose shock wave doesn't intersect the inlets during the 
air-breathing phase.

During the air-breathing phase, the engine inlets are inside the nose 
shock-cone, but are otherwise unaffected by the body, as far as I can 
see. This should make their design and testing so much more straight 
forward. Further, after the double-shock inlet, the flow into the 
pre-cooler is subsonic, which makes life a lot easier when it comes to 
developing that.

Sylvia.

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