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Once into the breach: SSTO's (was more Re: Life on Europa in scifi?)

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  Once into the breach: SSTO's (was more Re: Life on Europa in scifi?) "Robert Clark" <rgregoryclark@gmSPAMBLOCKail.com> - 2018-05-30 01:46 -0400
    Re: Once into the breach: SSTO's (was more Re: Life on Europa in scifi?) Thomas Koenig <tkoenig@netcologne.de> - 2018-06-01 20:07 +0000
      Re: Once into the breach: SSTO's (was more Re: Life on Europa in scifi?) J. Clarke <jclarke.873638@gmail.com> - 2018-06-01 22:51 -0400
        Re: Once into the breach: SSTO's (was more Re: Life on Europa in scifi?) Thomas Koenig <tkoenig@netcologne.de> - 2018-06-02 16:19 +0000
      Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) "Robert Clark" <rgregoryclark@gmSPAMBLOCKail.com> - 2018-06-03 04:17 -0400
        Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) J. Clarke <jclarke.873638@gmail.com> - 2018-06-03 04:38 -0400
          Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) Fred J. McCall <fjmccall@gmail.com> - 2018-06-03 01:58 -0700
            Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) J. Clarke <jclarke.873638@gmail.com> - 2018-06-03 05:10 -0400
              Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) Fred J. McCall <fjmccall@gmail.com> - 2018-06-03 14:06 -0700
                Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) J. Clarke <jclarke.873638@gmail.com> - 2018-06-03 17:59 -0400
                  Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) Fred J. McCall <fjmccall@gmail.com> - 2018-06-03 16:12 -0700
                    Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) J. Clarke <jclarke.873638@gmail.com> - 2018-06-03 19:54 -0400
                      Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) Fred J. McCall <fjmccall@gmail.com> - 2018-06-04 00:41 -0700
                    Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) Dimensional Traveler <dtravel@sonic.net> - 2018-06-03 19:36 -0700
                      Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) Fred J. McCall <fjmccall@gmail.com> - 2018-06-04 01:00 -0700
                        Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) Dimensional Traveler <dtravel@sonic.net> - 2018-06-04 07:32 -0700
                          Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) Steve Carroll <frelwizzen@gmail.com> - 2018-06-04 08:51 -0700
                          Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) Alan Baker <nunya@ness.biz> - 2018-06-04 09:13 -0700
                            Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) Steve Carroll <frelwizzen@gmail.com> - 2018-06-04 09:22 -0700
                          Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) Fred J. McCall <fjmccall@gmail.com> - 2018-06-04 16:08 -0700
                          Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) J. Clarke <jclarke.873638@gmail.com> - 2018-06-04 19:37 -0400
                            Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-05 07:25 -0400
                              Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) Fred J. McCall <fjmccall@gmail.com> - 2018-06-05 13:39 -0700
                                Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-06 06:44 -0400
                              Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) J. Clarke <jclarke.873638@gmail.com> - 2018-06-05 20:55 -0400
                                Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) Fred J. McCall <fjmccall@gmail.com> - 2018-06-05 22:59 -0700
                                  Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) Ninapenda Jibini <taustinca@gmail.com> - 2018-06-06 06:20 +0000
                                Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-06 06:50 -0400
                                  Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) J. Clarke <jclarke.873638@gmail.com> - 2018-06-06 20:54 -0400
                                    Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) Fred J. McCall <fjmccall@gmail.com> - 2018-06-06 18:16 -0700
                                    Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-07 11:51 -0400
                              Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) Thomas Koenig <tkoenig@netcologne.de> - 2018-06-06 06:21 +0000
                                Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) Fred J. McCall <fjmccall@gmail.com> - 2018-06-06 02:14 -0700
                                Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-06 07:08 -0400
                                  Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) Thomas Koenig <tkoenig@netcologne.de> - 2018-06-07 16:42 +0000
                                    Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) Fred J. McCall <fjmccall@gmail.com> - 2018-06-07 12:26 -0700
                                  Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) "Robert Clark" <rgregoryclark@gmSPAMBLOCKail.com> - 2018-06-10 20:16 -0400
                                    Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) Fred J. McCall <fjmccall@gmail.com> - 2018-06-10 20:13 -0700
                  Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) scott@slp53.sl.home (Scott Lurndal) - 2018-06-04 15:40 +0000
                    Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) Fred J. McCall <fjmccall@gmail.com> - 2018-06-04 16:11 -0700
          Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) Thomas Koenig <tkoenig@netcologne.de> - 2018-06-03 10:29 +0000
            Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) J. Clarke <jclarke.873638@gmail.com> - 2018-06-03 09:25 -0400
              Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) Fred J. McCall <fjmccall@gmail.com> - 2018-06-03 14:21 -0700
                Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) J. Clarke <jclarke.873638@gmail.com> - 2018-06-03 18:19 -0400
                  Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) Fred J. McCall <fjmccall@gmail.com> - 2018-06-03 16:15 -0700
                    Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) J. Clarke <jclarke.873638@gmail.com> - 2018-06-03 19:55 -0400
                      Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) Fred J. McCall <fjmccall@gmail.com> - 2018-06-04 00:44 -0700
              Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) "reber G=emc^2" <herbertglazier0@gmail.com> - 2018-06-05 14:58 -0700
                Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?) "hanson" <hanson@quick.net> - 2018-06-05 20:13 -0700
    Re: Once into the breach: SSTO's (was more Re: Life on Europa in scifi?) "reber G=emc^2" <herbertglazier0@gmail.com> - 2018-06-05 14:59 -0700
      Re: Once into the breach: SSTO's (was more Re: Life on Europa in scifi?) "hanson" <hanson@quick.net> - 2018-06-05 20:13 -0700

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#688772 — Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?)

On Mon, 4 Jun 2018 07:32:20 -0700, Dimensional Traveler
<dtravel@sonic.net> wrote:

>On 6/4/2018 1:00 AM, Fred J. McCall wrote:
>> Dimensional Traveler <dtravel@sonic.net> wrote on Sun, 3 Jun 2018
>> 19:36:02 -0700:
>> 
>>> On 6/3/2018 4:12 PM, Fred J. McCall wrote:
>>>> J. Clarke <jclarke.873638@gmail.com> wrote on Sun, 03 Jun 2018
>>>> 17:59:12 -0400:
>>>>
>>>>> On Sun, 03 Jun 2018 14:06:20 -0700, Fred J. McCall
>>>>> <fjmccall@gmail.com> wrote:
>>>>>
>>>>>> J. Clarke <jclarke.873638@gmail.com> wrote on Sun, 03 Jun 2018
>>>>>> 05:10:09 -0400:
>>>>>>
>>>>>>> On Sun, 03 Jun 2018 01:58:22 -0700, Fred J. McCall
>>>>>>> <fjmccall@gmail.com> wrote:
>>>>>>>
>>>>>>>> J. Clarke <jclarke.873638@gmail.com> wrote on Sun, 03 Jun 2018
>>>>>>>> 04:38:36 -0400:
>>>>>>>>
>>>>>>>>> On Sun, 3 Jun 2018 04:17:33 -0400, "Robert Clark"
>>>>>>>>> <rgregoryclark@gmSPAMBLOCKail.com> wrote:
>>>>>>>>>
>>>>>>>>>> ++++++++++++++++++++++++++++++++++++++++++++++++
>>>>>>>>>> "Thomas Koenig"  wrote in message
>>>>>>>>>> news:pes925$6i6$1@newsreader5.netcologne.de...
>>>>>>>>>>
>>>>>>>>>> Robert Clark <rgregoryclark@gmSPAMBLOCKail.com> schrieb:
>>>>>>>>>>> ===========================================================
>>>>>>>>>>> "J. Clarke"  wrote in message
>>>>>>>>>>> news:vqtogdhisj5bl28visfpnhkoc2li07ggm0@4ax.com...
>>>>>>>>>>>
>>>>>>>>>>> On Mon, 28 May 2018 11:30:57 -0700, Fred J. McCall
>>>>>>>>>>> <fjmccall@gmail.com> wrote:
>>>>>>>>>>>
>>>>>>>>>>> ...
>>>>>>>>>>>>>> Note that SpaceX has already acknowledged that the Falcon 9 first stage
>>>>>>>>>>>>>> and
>>>>>>>>>>>>>> the BFR stages will have SSTO capability, but with small payload.
>>>>>>>>>>>>>
>>>>>>>>>>>>> Source?  And I don't mean some throwaway comment or some blog post by
>>>>>>>>>>>>> somebody who doesn't work for SpaceX.
>>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>> Well, he's not exactly an employee but Elon Musk has said that a
>>>>>>>>>>>> Falcon 9 Full Thrust first stage reaches (a very low) orbit on an
>>>>>>>>>>>> expendable launch and that they deliberately give it a little boost
>>>>>>>>>>>> back toward the ground so that it doesn't hang around up there for a
>>>>>>>>>>>> month or two.
>>>>>>>>>>>
>>>>>>>>>>> Source?  Other than a tweet?
>>>>>>>>>>
>>>>>>>>>> Well, one could try plugging the available numbers into the rocket
>>>>>>>>>> equation.  I've taken them from
>>>>>>>>>> http://www.spaceflight101.net/falcon-9-v11.html (accuracy is
>>>>>>>>>> probably debatable, plus the numbers are old, so a grain of
>>>>>>>>>> salt is advised).
>>>>>>>>>
>>>>>>>>> Sorry, but your calculation using the rocket equation is not a
>>>>>>>>> statement by a SpaceX employee unless you are telling us now that you
>>>>>>>>> work at SpaceX.
>>>>>>>>>
>>>>>>>>> And you are neglecting drag completely so your analysis is not valid
>>>>>>>>> anyway.
>>>>>>>>>
>>>>>>>>
>>>>>>>> So believe what you want.  You're going to regardless.  Bottom line is
>>>>>>>> that almost any two stage booster has a first stage that can do SSTO
>>>>>>>> (with limited or no target).
>>>>>>>>
>>>>>>>
>>>>>>> Sez  you.  Still nothing from a SpaceX insider other than a tweet.
>>>>>>>
>>>>>>
>>>>>> Son, you just sit over there and be wrong.  I don't mind at all.
>>>>>>
>>>>>>>
>>>>>>> I don't believe what I want to.  I believe what is true.
>>>>>>>
>>>>>>
>>>>>> Oh, do you now?  Why is what you want to believe "true" with no proof?
>>>>>>
>>>>>
>>>>> I believe that it is true that no SSTO has ever made it to orbit.
>>>>>
>>>>
>>>> Which proves NOTHING.  You attempt to parlay that into "No current
>>>> first stage is capable of SSTO", which is a non sequitur.  There is a
>>>> difference between "not capable" and "not economic".
>>>>
>>>
>>> There is also a difference between "in theory" and "in practice".  In
>>> Theory SpaceX has two boosters that can do SSTO but until they actually
>>> DO go into orbit it is just theory and theory is not _proof_.
>>>
>> 
>> There is also a difference between 'shown' and 'demonstrated'.  I've
>> seen simulations that show that a Falcon 9 first stage can reach orbit
>> (but with practically no payload).
>
>No, there isn't a difference.  A computer simulation is just theory.

Depends on whether the model's been validated.  If NASA or SpaceX say
it I'll buy it--they both have track records of producing models that
predict what their hardware will do to a level that is adequate for
interplanetary navigation purposes.  Some random stranger on the
Internet is another story.

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#688866 — Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?)

In article <k3jbhdtp7rr11ef00mfv6grnpjj29cjc9a@4ax.com>, jclarke.873638
@gmail.com says...
> 
> On Mon, 4 Jun 2018 07:32:20 -0700, Dimensional Traveler
> <dtravel@sonic.net> wrote:
> 
> >On 6/4/2018 1:00 AM, Fred J. McCall wrote:
> >> Dimensional Traveler <dtravel@sonic.net> wrote on Sun, 3 Jun 2018
> >> 19:36:02 -0700:
> >> 
> >>> On 6/3/2018 4:12 PM, Fred J. McCall wrote:
> >>>> J. Clarke <jclarke.873638@gmail.com> wrote on Sun, 03 Jun 2018
> >>>> 17:59:12 -0400:
> >>>>
> >>>>> On Sun, 03 Jun 2018 14:06:20 -0700, Fred J. McCall
> >>>>> <fjmccall@gmail.com> wrote:
> >>>>>
> >>>>>> J. Clarke <jclarke.873638@gmail.com> wrote on Sun, 03 Jun 2018
> >>>>>> 05:10:09 -0400:
> >>>>>>
> >>>>>>> On Sun, 03 Jun 2018 01:58:22 -0700, Fred J. McCall
> >>>>>>> <fjmccall@gmail.com> wrote:
> >>>>>>>
> >>>>>>>> J. Clarke <jclarke.873638@gmail.com> wrote on Sun, 03 Jun 2018
> >>>>>>>> 04:38:36 -0400:
> >>>>>>>>
> >>>>>>>>> On Sun, 3 Jun 2018 04:17:33 -0400, "Robert Clark"
> >>>>>>>>> <rgregoryclark@gmSPAMBLOCKail.com> wrote:
> >>>>>>>>>
> >>>>>>>>>> ++++++++++++++++++++++++++++++++++++++++++++++++
> >>>>>>>>>> "Thomas Koenig"  wrote in message
> >>>>>>>>>> news:pes925$6i6$1@newsreader5.netcologne.de...
> >>>>>>>>>>
> >>>>>>>>>> Robert Clark <rgregoryclark@gmSPAMBLOCKail.com> schrieb:
> >>>>>>>>>>> ===========================================================
> >>>>>>>>>>> "J. Clarke"  wrote in message
> >>>>>>>>>>> news:vqtogdhisj5bl28visfpnhkoc2li07ggm0@4ax.com...
> >>>>>>>>>>>
> >>>>>>>>>>> On Mon, 28 May 2018 11:30:57 -0700, Fred J. McCall
> >>>>>>>>>>> <fjmccall@gmail.com> wrote:
> >>>>>>>>>>>
> >>>>>>>>>>> ...
> >>>>>>>>>>>>>> Note that SpaceX has already acknowledged that the Falcon 9 first stage
> >>>>>>>>>>>>>> and
> >>>>>>>>>>>>>> the BFR stages will have SSTO capability, but with small payload.
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> Source?  And I don't mean some throwaway comment or some blog post by
> >>>>>>>>>>>>> somebody who doesn't work for SpaceX.
> >>>>>>>>>>>>>
> >>>>>>>>>>>>
> >>>>>>>>>>>> Well, he's not exactly an employee but Elon Musk has said that a
> >>>>>>>>>>>> Falcon 9 Full Thrust first stage reaches (a very low) orbit on an
> >>>>>>>>>>>> expendable launch and that they deliberately give it a little boost
> >>>>>>>>>>>> back toward the ground so that it doesn't hang around up there for a
> >>>>>>>>>>>> month or two.
> >>>>>>>>>>>
> >>>>>>>>>>> Source?  Other than a tweet?
> >>>>>>>>>>
> >>>>>>>>>> Well, one could try plugging the available numbers into the rocket
> >>>>>>>>>> equation.  I've taken them from
> >>>>>>>>>> http://www.spaceflight101.net/falcon-9-v11.html (accuracy is
> >>>>>>>>>> probably debatable, plus the numbers are old, so a grain of
> >>>>>>>>>> salt is advised).
> >>>>>>>>>
> >>>>>>>>> Sorry, but your calculation using the rocket equation is not a
> >>>>>>>>> statement by a SpaceX employee unless you are telling us now that you
> >>>>>>>>> work at SpaceX.
> >>>>>>>>>
> >>>>>>>>> And you are neglecting drag completely so your analysis is not valid
> >>>>>>>>> anyway.
> >>>>>>>>>
> >>>>>>>>
> >>>>>>>> So believe what you want.  You're going to regardless.  Bottom line is
> >>>>>>>> that almost any two stage booster has a first stage that can do SSTO
> >>>>>>>> (with limited or no target).
> >>>>>>>>
> >>>>>>>
> >>>>>>> Sez  you.  Still nothing from a SpaceX insider other than a tweet.
> >>>>>>>
> >>>>>>
> >>>>>> Son, you just sit over there and be wrong.  I don't mind at all.
> >>>>>>
> >>>>>>>
> >>>>>>> I don't believe what I want to.  I believe what is true.
> >>>>>>>
> >>>>>>
> >>>>>> Oh, do you now?  Why is what you want to believe "true" with no proof?
> >>>>>>
> >>>>>
> >>>>> I believe that it is true that no SSTO has ever made it to orbit.
> >>>>>
> >>>>
> >>>> Which proves NOTHING.  You attempt to parlay that into "No current
> >>>> first stage is capable of SSTO", which is a non sequitur.  There is a
> >>>> difference between "not capable" and "not economic".
> >>>>
> >>>
> >>> There is also a difference between "in theory" and "in practice".  In
> >>> Theory SpaceX has two boosters that can do SSTO but until they actually
> >>> DO go into orbit it is just theory and theory is not _proof_.
> >>>
> >> 
> >> There is also a difference between 'shown' and 'demonstrated'.  I've
> >> seen simulations that show that a Falcon 9 first stage can reach orbit
> >> (but with practically no payload).
> >
> >No, there isn't a difference.  A computer simulation is just theory.
> 
> Depends on whether the model's been validated.  If NASA or SpaceX say
> it I'll buy it--they both have track records of producing models that
> predict what their hardware will do to a level that is adequate for
> interplanetary navigation purposes.  Some random stranger on the
> Internet is another story.
> 

Just because you are unwilling or unable to do the math yourself doesn't 
mean the math is wrong.  Math is math.

We've had this debate a long, long time ago in the sci.space newsgroups.  
The fact is that there are many stages which are theoretically capable 
of performing SSTO with minimal payload.  No one has ever done it 
because the cost to get that payload into orbit is typically higher than 
it would be if you just used a smaller TSTO (or higher number of 
stages).  In other words, it just makes no sense to fly a disposable 
SSTO.  That and the "serious" space organizations just wouldn't do 
anything like this.  They've lost the drive to do anything innovative 
like this.

Now a *reusable* SSTO is a whole other kettle of fish.  I'd imagine that 
we'll see BFS do an SSTO flight.  Why?  #1 because it will be reusable, 
so the cost of the flight will be a small multiplier on top of the 
propellant costs.  #2 it would be a useful test flight since BFS will be 
tested before the BFR first stage.  #3 because Elon Musk likes to do 
things that promote his products in a highly visible way.  To be the 
first to launch an land a reusable SSTO will be one for the record books 
for sure.  #4 Musk has already said that BFS will be SSTO capable.

So, we shall see.  

Jeff
-- 
All opinions posted by me on Usenet News are mine, and mine alone.  
These posts do not reflect the opinions of my family, friends, 
employer, or any organization that I am a member of.

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#688943 — Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?)

Jeff Findley <jfindley@cinci.nospam.rr.com> wrote on Tue, 5 Jun 2018
07:25:07 -0400:

>In article <k3jbhdtp7rr11ef00mfv6grnpjj29cjc9a@4ax.com>, jclarke.873638
>@gmail.com says...
>> 
>> On Mon, 4 Jun 2018 07:32:20 -0700, Dimensional Traveler
>> <dtravel@sonic.net> wrote:
>> 
>> >On 6/4/2018 1:00 AM, Fred J. McCall wrote:
>> >> Dimensional Traveler <dtravel@sonic.net> wrote on Sun, 3 Jun 2018
>> >> 19:36:02 -0700:
>> >> 
>> >>> On 6/3/2018 4:12 PM, Fred J. McCall wrote:
>> >>>> J. Clarke <jclarke.873638@gmail.com> wrote on Sun, 03 Jun 2018
>> >>>> 17:59:12 -0400:
>> >>>>
>> >>>>> On Sun, 03 Jun 2018 14:06:20 -0700, Fred J. McCall
>> >>>>> <fjmccall@gmail.com> wrote:
>> >>>>>
>> >>>>>> J. Clarke <jclarke.873638@gmail.com> wrote on Sun, 03 Jun 2018
>> >>>>>> 05:10:09 -0400:
>> >>>>>>
>> >>>>>>> On Sun, 03 Jun 2018 01:58:22 -0700, Fred J. McCall
>> >>>>>>> <fjmccall@gmail.com> wrote:
>> >>>>>>>
>> >>>>>>>> J. Clarke <jclarke.873638@gmail.com> wrote on Sun, 03 Jun 2018
>> >>>>>>>> 04:38:36 -0400:
>> >>>>>>>>
>> >>>>>>>>> On Sun, 3 Jun 2018 04:17:33 -0400, "Robert Clark"
>> >>>>>>>>> <rgregoryclark@gmSPAMBLOCKail.com> wrote:
>> >>>>>>>>>
>> >>>>>>>>>> ++++++++++++++++++++++++++++++++++++++++++++++++
>> >>>>>>>>>> "Thomas Koenig"  wrote in message
>> >>>>>>>>>> news:pes925$6i6$1@newsreader5.netcologne.de...
>> >>>>>>>>>>
>> >>>>>>>>>> Robert Clark <rgregoryclark@gmSPAMBLOCKail.com> schrieb:
>> >>>>>>>>>>> ===========================================================
>> >>>>>>>>>>> "J. Clarke"  wrote in message
>> >>>>>>>>>>> news:vqtogdhisj5bl28visfpnhkoc2li07ggm0@4ax.com...
>> >>>>>>>>>>>
>> >>>>>>>>>>> On Mon, 28 May 2018 11:30:57 -0700, Fred J. McCall
>> >>>>>>>>>>> <fjmccall@gmail.com> wrote:
>> >>>>>>>>>>>
>> >>>>>>>>>>> ...
>> >>>>>>>>>>>>>> Note that SpaceX has already acknowledged that the Falcon 9 first stage
>> >>>>>>>>>>>>>> and
>> >>>>>>>>>>>>>> the BFR stages will have SSTO capability, but with small payload.
>> >>>>>>>>>>>>>
>> >>>>>>>>>>>>> Source?  And I don't mean some throwaway comment or some blog post by
>> >>>>>>>>>>>>> somebody who doesn't work for SpaceX.
>> >>>>>>>>>>>>>
>> >>>>>>>>>>>>
>> >>>>>>>>>>>> Well, he's not exactly an employee but Elon Musk has said that a
>> >>>>>>>>>>>> Falcon 9 Full Thrust first stage reaches (a very low) orbit on an
>> >>>>>>>>>>>> expendable launch and that they deliberately give it a little boost
>> >>>>>>>>>>>> back toward the ground so that it doesn't hang around up there for a
>> >>>>>>>>>>>> month or two.
>> >>>>>>>>>>>
>> >>>>>>>>>>> Source?  Other than a tweet?
>> >>>>>>>>>>
>> >>>>>>>>>> Well, one could try plugging the available numbers into the rocket
>> >>>>>>>>>> equation.  I've taken them from
>> >>>>>>>>>> http://www.spaceflight101.net/falcon-9-v11.html (accuracy is
>> >>>>>>>>>> probably debatable, plus the numbers are old, so a grain of
>> >>>>>>>>>> salt is advised).
>> >>>>>>>>>
>> >>>>>>>>> Sorry, but your calculation using the rocket equation is not a
>> >>>>>>>>> statement by a SpaceX employee unless you are telling us now that you
>> >>>>>>>>> work at SpaceX.
>> >>>>>>>>>
>> >>>>>>>>> And you are neglecting drag completely so your analysis is not valid
>> >>>>>>>>> anyway.
>> >>>>>>>>>
>> >>>>>>>>
>> >>>>>>>> So believe what you want.  You're going to regardless.  Bottom line is
>> >>>>>>>> that almost any two stage booster has a first stage that can do SSTO
>> >>>>>>>> (with limited or no target).
>> >>>>>>>>
>> >>>>>>>
>> >>>>>>> Sez  you.  Still nothing from a SpaceX insider other than a tweet.
>> >>>>>>>
>> >>>>>>
>> >>>>>> Son, you just sit over there and be wrong.  I don't mind at all.
>> >>>>>>
>> >>>>>>>
>> >>>>>>> I don't believe what I want to.  I believe what is true.
>> >>>>>>>
>> >>>>>>
>> >>>>>> Oh, do you now?  Why is what you want to believe "true" with no proof?
>> >>>>>>
>> >>>>>
>> >>>>> I believe that it is true that no SSTO has ever made it to orbit.
>> >>>>>
>> >>>>
>> >>>> Which proves NOTHING.  You attempt to parlay that into "No current
>> >>>> first stage is capable of SSTO", which is a non sequitur.  There is a
>> >>>> difference between "not capable" and "not economic".
>> >>>>
>> >>>
>> >>> There is also a difference between "in theory" and "in practice".  In
>> >>> Theory SpaceX has two boosters that can do SSTO but until they actually
>> >>> DO go into orbit it is just theory and theory is not _proof_.
>> >>>
>> >> 
>> >> There is also a difference between 'shown' and 'demonstrated'.  I've
>> >> seen simulations that show that a Falcon 9 first stage can reach orbit
>> >> (but with practically no payload).
>> >
>> >No, there isn't a difference.  A computer simulation is just theory.
>> 
>> Depends on whether the model's been validated.  If NASA or SpaceX say
>> it I'll buy it--they both have track records of producing models that
>> predict what their hardware will do to a level that is adequate for
>> interplanetary navigation purposes.  Some random stranger on the
>> Internet is another story.
>> 
>
>Just because you are unwilling or unable to do the math yourself doesn't 
>mean the math is wrong.  Math is math.
>
>We've had this debate a long, long time ago in the sci.space newsgroups.  
>The fact is that there are many stages which are theoretically capable 
>of performing SSTO with minimal payload.  No one has ever done it 
>because the cost to get that payload into orbit is typically higher than 
>it would be if you just used a smaller TSTO (or higher number of 
>stages).  In other words, it just makes no sense to fly a disposable 
>SSTO.  That and the "serious" space organizations just wouldn't do 
>anything like this.  They've lost the drive to do anything innovative 
>like this.
>

Actually some smaller players still are.  Haas wants to launch their
SSTO linear aerospike vehicle before the end of the year.

http://www.arcaspace.com/


-- 
"The reasonable man adapts himself to the world; the unreasonable 
 man persists in trying to adapt the world to himself. Therefore, 
 all progress depends on the unreasonable man."
                                      --George Bernard Shaw

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#689140 — Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?)

In article <hssdhdpmgat9b4879cs11s1kvhh7fc7c5o@4ax.com>, 
fjmccall@gmail.com says...
> >> Depends on whether the model's been validated.  If NASA or SpaceX say
> >> it I'll buy it--they both have track records of producing models that
> >> predict what their hardware will do to a level that is adequate for
> >> interplanetary navigation purposes.  Some random stranger on the
> >> Internet is another story.
> >> 
> >
> >Just because you are unwilling or unable to do the math yourself doesn't 
> >mean the math is wrong.  Math is math.
> >
> >We've had this debate a long, long time ago in the sci.space newsgroups.  
> >The fact is that there are many stages which are theoretically capable 
> >of performing SSTO with minimal payload.  No one has ever done it 
> >because the cost to get that payload into orbit is typically higher than 
> >it would be if you just used a smaller TSTO (or higher number of 
> >stages).  In other words, it just makes no sense to fly a disposable 
> >SSTO.  That and the "serious" space organizations just wouldn't do 
> >anything like this.  They've lost the drive to do anything innovative 
> >like this.
> >
> 
> Actually some smaller players still are.  Haas wants to launch their
> SSTO linear aerospike vehicle before the end of the year.
> 
> http://www.arcaspace.com/
> 

I've seen this.  I commend their efforts.  But, why in the world would 
you use a linear aerospike on a vehicle with a circular cross section?  
There are going to be losses at the ends of a linear aerospike.  Using 
an annular aerospike seems like a no-brainer, so there must be some 
reason for this oddity.  

Still, it's good to see someone actually trying to fly an aerospike.  
There are still people that don't believe it will work, despite the 
evidence to the contrary.  The only way to prove them wrong is to 
actually fly a vehicle from sea level to vacuum and verify the 
performance of the engine along the flight path.

Jeff
-- 
All opinions posted by me on Usenet News are mine, and mine alone.  
These posts do not reflect the opinions of my family, friends, 
employer, or any organization that I am a member of.

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#689030 — Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?)

On Tue, 5 Jun 2018 07:25:07 -0400, Jeff Findley
<jfindley@cinci.nospam.rr.com> wrote:

>In article <k3jbhdtp7rr11ef00mfv6grnpjj29cjc9a@4ax.com>, jclarke.873638
>@gmail.com says...
>> 
>> On Mon, 4 Jun 2018 07:32:20 -0700, Dimensional Traveler
>> <dtravel@sonic.net> wrote:
>> 
>> >On 6/4/2018 1:00 AM, Fred J. McCall wrote:
>> >> Dimensional Traveler <dtravel@sonic.net> wrote on Sun, 3 Jun 2018
>> >> 19:36:02 -0700:
>> >> 
>> >>> On 6/3/2018 4:12 PM, Fred J. McCall wrote:
>> >>>> J. Clarke <jclarke.873638@gmail.com> wrote on Sun, 03 Jun 2018
>> >>>> 17:59:12 -0400:
>> >>>>
>> >>>>> On Sun, 03 Jun 2018 14:06:20 -0700, Fred J. McCall
>> >>>>> <fjmccall@gmail.com> wrote:
>> >>>>>
>> >>>>>> J. Clarke <jclarke.873638@gmail.com> wrote on Sun, 03 Jun 2018
>> >>>>>> 05:10:09 -0400:
>> >>>>>>
>> >>>>>>> On Sun, 03 Jun 2018 01:58:22 -0700, Fred J. McCall
>> >>>>>>> <fjmccall@gmail.com> wrote:
>> >>>>>>>
>> >>>>>>>> J. Clarke <jclarke.873638@gmail.com> wrote on Sun, 03 Jun 2018
>> >>>>>>>> 04:38:36 -0400:
>> >>>>>>>>
>> >>>>>>>>> On Sun, 3 Jun 2018 04:17:33 -0400, "Robert Clark"
>> >>>>>>>>> <rgregoryclark@gmSPAMBLOCKail.com> wrote:
>> >>>>>>>>>
>> >>>>>>>>>> ++++++++++++++++++++++++++++++++++++++++++++++++
>> >>>>>>>>>> "Thomas Koenig"  wrote in message
>> >>>>>>>>>> news:pes925$6i6$1@newsreader5.netcologne.de...
>> >>>>>>>>>>
>> >>>>>>>>>> Robert Clark <rgregoryclark@gmSPAMBLOCKail.com> schrieb:
>> >>>>>>>>>>> ===========================================================
>> >>>>>>>>>>> "J. Clarke"  wrote in message
>> >>>>>>>>>>> news:vqtogdhisj5bl28visfpnhkoc2li07ggm0@4ax.com...
>> >>>>>>>>>>>
>> >>>>>>>>>>> On Mon, 28 May 2018 11:30:57 -0700, Fred J. McCall
>> >>>>>>>>>>> <fjmccall@gmail.com> wrote:
>> >>>>>>>>>>>
>> >>>>>>>>>>> ...
>> >>>>>>>>>>>>>> Note that SpaceX has already acknowledged that the Falcon 9 first stage
>> >>>>>>>>>>>>>> and
>> >>>>>>>>>>>>>> the BFR stages will have SSTO capability, but with small payload.
>> >>>>>>>>>>>>>
>> >>>>>>>>>>>>> Source?  And I don't mean some throwaway comment or some blog post by
>> >>>>>>>>>>>>> somebody who doesn't work for SpaceX.
>> >>>>>>>>>>>>>
>> >>>>>>>>>>>>
>> >>>>>>>>>>>> Well, he's not exactly an employee but Elon Musk has said that a
>> >>>>>>>>>>>> Falcon 9 Full Thrust first stage reaches (a very low) orbit on an
>> >>>>>>>>>>>> expendable launch and that they deliberately give it a little boost
>> >>>>>>>>>>>> back toward the ground so that it doesn't hang around up there for a
>> >>>>>>>>>>>> month or two.
>> >>>>>>>>>>>
>> >>>>>>>>>>> Source?  Other than a tweet?
>> >>>>>>>>>>
>> >>>>>>>>>> Well, one could try plugging the available numbers into the rocket
>> >>>>>>>>>> equation.  I've taken them from
>> >>>>>>>>>> http://www.spaceflight101.net/falcon-9-v11.html (accuracy is
>> >>>>>>>>>> probably debatable, plus the numbers are old, so a grain of
>> >>>>>>>>>> salt is advised).
>> >>>>>>>>>
>> >>>>>>>>> Sorry, but your calculation using the rocket equation is not a
>> >>>>>>>>> statement by a SpaceX employee unless you are telling us now that you
>> >>>>>>>>> work at SpaceX.
>> >>>>>>>>>
>> >>>>>>>>> And you are neglecting drag completely so your analysis is not valid
>> >>>>>>>>> anyway.
>> >>>>>>>>>
>> >>>>>>>>
>> >>>>>>>> So believe what you want.  You're going to regardless.  Bottom line is
>> >>>>>>>> that almost any two stage booster has a first stage that can do SSTO
>> >>>>>>>> (with limited or no target).
>> >>>>>>>>
>> >>>>>>>
>> >>>>>>> Sez  you.  Still nothing from a SpaceX insider other than a tweet.
>> >>>>>>>
>> >>>>>>
>> >>>>>> Son, you just sit over there and be wrong.  I don't mind at all.
>> >>>>>>
>> >>>>>>>
>> >>>>>>> I don't believe what I want to.  I believe what is true.
>> >>>>>>>
>> >>>>>>
>> >>>>>> Oh, do you now?  Why is what you want to believe "true" with no proof?
>> >>>>>>
>> >>>>>
>> >>>>> I believe that it is true that no SSTO has ever made it to orbit.
>> >>>>>
>> >>>>
>> >>>> Which proves NOTHING.  You attempt to parlay that into "No current
>> >>>> first stage is capable of SSTO", which is a non sequitur.  There is a
>> >>>> difference between "not capable" and "not economic".
>> >>>>
>> >>>
>> >>> There is also a difference between "in theory" and "in practice".  In
>> >>> Theory SpaceX has two boosters that can do SSTO but until they actually
>> >>> DO go into orbit it is just theory and theory is not _proof_.
>> >>>
>> >> 
>> >> There is also a difference between 'shown' and 'demonstrated'.  I've
>> >> seen simulations that show that a Falcon 9 first stage can reach orbit
>> >> (but with practically no payload).
>> >
>> >No, there isn't a difference.  A computer simulation is just theory.
>> 
>> Depends on whether the model's been validated.  If NASA or SpaceX say
>> it I'll buy it--they both have track records of producing models that
>> predict what their hardware will do to a level that is adequate for
>> interplanetary navigation purposes.  Some random stranger on the
>> Internet is another story.
>> 
>
>Just because you are unwilling or unable to do the math yourself doesn't 
>mean the math is wrong.  Math is math.

But math is not physics.  If the math does not accurately describe the
physics then the math is irrelevant.

>We've had this debate a long, long time ago in the sci.space newsgroups.  
>The fact is that there are many stages which are theoretically capable 
>of performing SSTO with minimal payload.

According to you.

>No one has ever done it 
>because the cost to get that payload into orbit is typically higher than 
>it would be if you just used a smaller TSTO (or higher number of 
>stages).  In other words, it just makes no sense to fly a disposable 
>SSTO.  That and the "serious" space organizations just wouldn't do 
>anything like this.  They've lost the drive to do anything innovative 
>like this.
>
>Now a *reusable* SSTO is a whole other kettle of fish.  I'd imagine that 
>we'll see BFS do an SSTO flight.  Why?  #1 because it will be reusable, 
>so the cost of the flight will be a small multiplier on top of the 
>propellant costs.  #2 it would be a useful test flight since BFS will be 
>tested before the BFR first stage.  #3 because Elon Musk likes to do 
>things that promote his products in a highly visible way.  To be the 
>first to launch an land a reusable SSTO will be one for the record books 
>for sure.  #4 Musk has already said that BFS will be SSTO capable.

Musk says a lot of things.  Some of them turn out to be true.

>So, we shall see.  
>
>Jeff

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#689127 — Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?)

J. Clarke <jclarke.873638@gmail.com> wrote on Tue, 05 Jun 2018
20:55:15 -0400:

>On Tue, 5 Jun 2018 07:25:07 -0400, Jeff Findley
><jfindley@cinci.nospam.rr.com> wrote:
>
>>In article <k3jbhdtp7rr11ef00mfv6grnpjj29cjc9a@4ax.com>, jclarke.873638
>>@gmail.com says...
>>> 
>>> On Mon, 4 Jun 2018 07:32:20 -0700, Dimensional Traveler
>>> <dtravel@sonic.net> wrote:
>>> 
>>> >On 6/4/2018 1:00 AM, Fred J. McCall wrote:
>>> >> Dimensional Traveler <dtravel@sonic.net> wrote on Sun, 3 Jun 2018
>>> >> 19:36:02 -0700:
>>> >> 
>>> >>> On 6/3/2018 4:12 PM, Fred J. McCall wrote:
>>> >>>> J. Clarke <jclarke.873638@gmail.com> wrote on Sun, 03 Jun 2018
>>> >>>> 17:59:12 -0400:
>>> >>>>
>>> >>>>> On Sun, 03 Jun 2018 14:06:20 -0700, Fred J. McCall
>>> >>>>> <fjmccall@gmail.com> wrote:
>>> >>>>>
>>> >>>>>> J. Clarke <jclarke.873638@gmail.com> wrote on Sun, 03 Jun 2018
>>> >>>>>> 05:10:09 -0400:
>>> >>>>>>
>>> >>>>>>> On Sun, 03 Jun 2018 01:58:22 -0700, Fred J. McCall
>>> >>>>>>> <fjmccall@gmail.com> wrote:
>>> >>>>>>>
>>> >>>>>>>> J. Clarke <jclarke.873638@gmail.com> wrote on Sun, 03 Jun 2018
>>> >>>>>>>> 04:38:36 -0400:
>>> >>>>>>>>
>>> >>>>>>>>> On Sun, 3 Jun 2018 04:17:33 -0400, "Robert Clark"
>>> >>>>>>>>> <rgregoryclark@gmSPAMBLOCKail.com> wrote:
>>> >>>>>>>>>
>>> >>>>>>>>>> ++++++++++++++++++++++++++++++++++++++++++++++++
>>> >>>>>>>>>> "Thomas Koenig"  wrote in message
>>> >>>>>>>>>> news:pes925$6i6$1@newsreader5.netcologne.de...
>>> >>>>>>>>>>
>>> >>>>>>>>>> Robert Clark <rgregoryclark@gmSPAMBLOCKail.com> schrieb:
>>> >>>>>>>>>>> ===========================================================
>>> >>>>>>>>>>> "J. Clarke"  wrote in message
>>> >>>>>>>>>>> news:vqtogdhisj5bl28visfpnhkoc2li07ggm0@4ax.com...
>>> >>>>>>>>>>>
>>> >>>>>>>>>>> On Mon, 28 May 2018 11:30:57 -0700, Fred J. McCall
>>> >>>>>>>>>>> <fjmccall@gmail.com> wrote:
>>> >>>>>>>>>>>
>>> >>>>>>>>>>> ...
>>> >>>>>>>>>>>>>> Note that SpaceX has already acknowledged that the Falcon 9 first stage
>>> >>>>>>>>>>>>>> and
>>> >>>>>>>>>>>>>> the BFR stages will have SSTO capability, but with small payload.
>>> >>>>>>>>>>>>>
>>> >>>>>>>>>>>>> Source?  And I don't mean some throwaway comment or some blog post by
>>> >>>>>>>>>>>>> somebody who doesn't work for SpaceX.
>>> >>>>>>>>>>>>>
>>> >>>>>>>>>>>>
>>> >>>>>>>>>>>> Well, he's not exactly an employee but Elon Musk has said that a
>>> >>>>>>>>>>>> Falcon 9 Full Thrust first stage reaches (a very low) orbit on an
>>> >>>>>>>>>>>> expendable launch and that they deliberately give it a little boost
>>> >>>>>>>>>>>> back toward the ground so that it doesn't hang around up there for a
>>> >>>>>>>>>>>> month or two.
>>> >>>>>>>>>>>
>>> >>>>>>>>>>> Source?  Other than a tweet?
>>> >>>>>>>>>>
>>> >>>>>>>>>> Well, one could try plugging the available numbers into the rocket
>>> >>>>>>>>>> equation.  I've taken them from
>>> >>>>>>>>>> http://www.spaceflight101.net/falcon-9-v11.html (accuracy is
>>> >>>>>>>>>> probably debatable, plus the numbers are old, so a grain of
>>> >>>>>>>>>> salt is advised).
>>> >>>>>>>>>
>>> >>>>>>>>> Sorry, but your calculation using the rocket equation is not a
>>> >>>>>>>>> statement by a SpaceX employee unless you are telling us now that you
>>> >>>>>>>>> work at SpaceX.
>>> >>>>>>>>>
>>> >>>>>>>>> And you are neglecting drag completely so your analysis is not valid
>>> >>>>>>>>> anyway.
>>> >>>>>>>>>
>>> >>>>>>>>
>>> >>>>>>>> So believe what you want.  You're going to regardless.  Bottom line is
>>> >>>>>>>> that almost any two stage booster has a first stage that can do SSTO
>>> >>>>>>>> (with limited or no target).
>>> >>>>>>>>
>>> >>>>>>>
>>> >>>>>>> Sez  you.  Still nothing from a SpaceX insider other than a tweet.
>>> >>>>>>>
>>> >>>>>>
>>> >>>>>> Son, you just sit over there and be wrong.  I don't mind at all.
>>> >>>>>>
>>> >>>>>>>
>>> >>>>>>> I don't believe what I want to.  I believe what is true.
>>> >>>>>>>
>>> >>>>>>
>>> >>>>>> Oh, do you now?  Why is what you want to believe "true" with no proof?
>>> >>>>>>
>>> >>>>>
>>> >>>>> I believe that it is true that no SSTO has ever made it to orbit.
>>> >>>>>
>>> >>>>
>>> >>>> Which proves NOTHING.  You attempt to parlay that into "No current
>>> >>>> first stage is capable of SSTO", which is a non sequitur.  There is a
>>> >>>> difference between "not capable" and "not economic".
>>> >>>>
>>> >>>
>>> >>> There is also a difference between "in theory" and "in practice".  In
>>> >>> Theory SpaceX has two boosters that can do SSTO but until they actually
>>> >>> DO go into orbit it is just theory and theory is not _proof_.
>>> >>>
>>> >> 
>>> >> There is also a difference between 'shown' and 'demonstrated'.  I've
>>> >> seen simulations that show that a Falcon 9 first stage can reach orbit
>>> >> (but with practically no payload).
>>> >
>>> >No, there isn't a difference.  A computer simulation is just theory.
>>> 
>>> Depends on whether the model's been validated.  If NASA or SpaceX say
>>> it I'll buy it--they both have track records of producing models that
>>> predict what their hardware will do to a level that is adequate for
>>> interplanetary navigation purposes.  Some random stranger on the
>>> Internet is another story.
>>> 
>>
>>Just because you are unwilling or unable to do the math yourself doesn't 
>>mean the math is wrong.  Math is math.
>>
>
>But math is not physics.  If the math does not accurately describe the
>physics then the math is irrelevant.
>

Sorry, but now.  If the math doesn't adequately describe the physics
the PHYSICS is wrong.  You understand that physics is just theory
based on math, right?

>
>>
>>We've had this debate a long, long time ago in the sci.space newsgroups.  
>>The fact is that there are many stages which are theoretically capable 
>>of performing SSTO with minimal payload.
>>
>
>According to you.
>

According to pretty much everyone who knows anything about the field.
Then there's you...

>
>>
>>No one has ever done it 
>>because the cost to get that payload into orbit is typically higher than 
>>it would be if you just used a smaller TSTO (or higher number of 
>>stages).  In other words, it just makes no sense to fly a disposable 
>>SSTO.  That and the "serious" space organizations just wouldn't do 
>>anything like this.  They've lost the drive to do anything innovative 
>>like this.
>>
>>Now a *reusable* SSTO is a whole other kettle of fish.  I'd imagine that 
>>we'll see BFS do an SSTO flight.  Why?  #1 because it will be reusable, 
>>so the cost of the flight will be a small multiplier on top of the 
>>propellant costs.  #2 it would be a useful test flight since BFS will be 
>>tested before the BFR first stage.  #3 because Elon Musk likes to do 
>>things that promote his products in a highly visible way.  To be the 
>>first to launch an land a reusable SSTO will be one for the record books 
>>for sure.  #4 Musk has already said that BFS will be SSTO capable.
>>
>
>Musk says a lot of things.  Some of them turn out to be true.
>

Ah, the old "if he doesn't agree with me he's lying" fallacy.  He's
made billions of dollars being 'wrong'.  What have you made being
'right'?


-- 
"Some people get lost in thought because it's such unfamiliar
 territory."
                                      --G. Behn

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

#689130 — Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?)

Fred J. McCall <fjmccall@gmail.com> wrote in
news:ittehdpmtm1rh1u58mp25d8datflmjfohn@4ax.com: 

> J. Clarke <jclarke.873638@gmail.com> wrote on Tue, 05 Jun 2018
> 20:55:15 -0400:
> 
>>On Tue, 5 Jun 2018 07:25:07 -0400, Jeff Findley
>><jfindley@cinci.nospam.rr.com> wrote:
>>
>>>In article <k3jbhdtp7rr11ef00mfv6grnpjj29cjc9a@4ax.com>,
>>>jclarke.873638 @gmail.com says...
>>>> 
>>>> On Mon, 4 Jun 2018 07:32:20 -0700, Dimensional Traveler
>>>> <dtravel@sonic.net> wrote:
>>>> 
>>>> >On 6/4/2018 1:00 AM, Fred J. McCall wrote:
>>>> >> Dimensional Traveler <dtravel@sonic.net> wrote on Sun, 3
>>>> >> Jun 2018 19:36:02 -0700:
>>>> >> 
>>>> >>> On 6/3/2018 4:12 PM, Fred J. McCall wrote:
>>>> >>>> J. Clarke <jclarke.873638@gmail.com> wrote on Sun, 03
>>>> >>>> Jun 2018 17:59:12 -0400:
>>>> >>>>
>>>> >>>>> On Sun, 03 Jun 2018 14:06:20 -0700, Fred J. McCall
>>>> >>>>> <fjmccall@gmail.com> wrote:
>>>> >>>>>
>>>> >>>>>> J. Clarke <jclarke.873638@gmail.com> wrote on Sun, 03
>>>> >>>>>> Jun 2018 05:10:09 -0400:
>>>> >>>>>>
>>>> >>>>>>> On Sun, 03 Jun 2018 01:58:22 -0700, Fred J. McCall
>>>> >>>>>>> <fjmccall@gmail.com> wrote:
>>>> >>>>>>>
>>>> >>>>>>>> J. Clarke <jclarke.873638@gmail.com> wrote on Sun,
>>>> >>>>>>>> 03 Jun 2018 04:38:36 -0400:
>>>> >>>>>>>>
>>>> >>>>>>>>> On Sun, 3 Jun 2018 04:17:33 -0400, "Robert Clark"
>>>> >>>>>>>>> <rgregoryclark@gmSPAMBLOCKail.com> wrote:
>>>> >>>>>>>>>
>>>> >>>>>>>>>> ++++++++++++++++++++++++++++++++++++++++++++++++
>>>> >>>>>>>>>> "Thomas Koenig"  wrote in message
>>>> >>>>>>>>>> news:pes925$6i6$1@newsreader5.netcologne.de...
>>>> >>>>>>>>>>
>>>> >>>>>>>>>> Robert Clark <rgregoryclark@gmSPAMBLOCKail.com>
>>>> >>>>>>>>>> schrieb: 
>>>> >>>>>>>>>>> ==================================================
>>>> >>>>>>>>>>> ========= "J. Clarke"  wrote in message
>>>> >>>>>>>>>>> news:vqtogdhisj5bl28visfpnhkoc2li07ggm0@4ax.com...
>>>> >>>>>>>>>>>
>>>> >>>>>>>>>>> On Mon, 28 May 2018 11:30:57 -0700, Fred J.
>>>> >>>>>>>>>>> McCall <fjmccall@gmail.com> wrote:
>>>> >>>>>>>>>>>
>>>> >>>>>>>>>>> ...
>>>> >>>>>>>>>>>>>> Note that SpaceX has already acknowledged that
>>>> >>>>>>>>>>>>>> the Falcon 9 first stage and
>>>> >>>>>>>>>>>>>> the BFR stages will have SSTO capability, but
>>>> >>>>>>>>>>>>>> with small payload. 
>>>> >>>>>>>>>>>>>
>>>> >>>>>>>>>>>>> Source?  And I don't mean some throwaway
>>>> >>>>>>>>>>>>> comment or some blog post by 
>>>> >>>>>>>>>>>>> somebody who doesn't work for SpaceX.
>>>> >>>>>>>>>>>>>
>>>> >>>>>>>>>>>>
>>>> >>>>>>>>>>>> Well, he's not exactly an employee but Elon Musk
>>>> >>>>>>>>>>>> has said that a Falcon 9 Full Thrust first stage
>>>> >>>>>>>>>>>> reaches (a very low) orbit on an 
>>>> >>>>>>>>>>>> expendable launch and that they deliberately
>>>> >>>>>>>>>>>> give it a little boost back toward the ground so
>>>> >>>>>>>>>>>> that it doesn't hang around up there for a 
>>>> >>>>>>>>>>>> month or two.
>>>> >>>>>>>>>>>
>>>> >>>>>>>>>>> Source?  Other than a tweet?
>>>> >>>>>>>>>>
>>>> >>>>>>>>>> Well, one could try plugging the available numbers
>>>> >>>>>>>>>> into the rocket equation.  I've taken them from
>>>> >>>>>>>>>> http://www.spaceflight101.net/falcon-9-v11.html
>>>> >>>>>>>>>> (accuracy is probably debatable, plus the numbers
>>>> >>>>>>>>>> are old, so a grain of salt is advised).
>>>> >>>>>>>>>
>>>> >>>>>>>>> Sorry, but your calculation using the rocket
>>>> >>>>>>>>> equation is not a statement by a SpaceX employee
>>>> >>>>>>>>> unless you are telling us now that you 
>>>> >>>>>>>>> work at SpaceX.
>>>> >>>>>>>>>
>>>> >>>>>>>>> And you are neglecting drag completely so your
>>>> >>>>>>>>> analysis is not valid anyway.
>>>> >>>>>>>>>
>>>> >>>>>>>>
>>>> >>>>>>>> So believe what you want.  You're going to
>>>> >>>>>>>> regardless.  Bottom line is that almost any two
>>>> >>>>>>>> stage booster has a first stage that can do SSTO 
>>>> >>>>>>>> (with limited or no target).
>>>> >>>>>>>>
>>>> >>>>>>>
>>>> >>>>>>> Sez  you.  Still nothing from a SpaceX insider other
>>>> >>>>>>> than a tweet. 
>>>> >>>>>>>
>>>> >>>>>>
>>>> >>>>>> Son, you just sit over there and be wrong.  I don't
>>>> >>>>>> mind at all. 
>>>> >>>>>>
>>>> >>>>>>>
>>>> >>>>>>> I don't believe what I want to.  I believe what is
>>>> >>>>>>> true. 
>>>> >>>>>>>
>>>> >>>>>>
>>>> >>>>>> Oh, do you now?  Why is what you want to believe
>>>> >>>>>> "true" with no proof? 
>>>> >>>>>>
>>>> >>>>>
>>>> >>>>> I believe that it is true that no SSTO has ever made it
>>>> >>>>> to orbit. 
>>>> >>>>>
>>>> >>>>
>>>> >>>> Which proves NOTHING.  You attempt to parlay that into
>>>> >>>> "No current first stage is capable of SSTO", which is a
>>>> >>>> non sequitur.  There is a difference between "not
>>>> >>>> capable" and "not economic". 
>>>> >>>>
>>>> >>>
>>>> >>> There is also a difference between "in theory" and "in
>>>> >>> practice".  In Theory SpaceX has two boosters that can do
>>>> >>> SSTO but until they actually DO go into orbit it is just
>>>> >>> theory and theory is not _proof_. 
>>>> >>>
>>>> >> 
>>>> >> There is also a difference between 'shown' and
>>>> >> 'demonstrated'.  I've seen simulations that show that a
>>>> >> Falcon 9 first stage can reach orbit (but with practically
>>>> >> no payload). 
>>>> >
>>>> >No, there isn't a difference.  A computer simulation is just
>>>> >theory. 
>>>> 
>>>> Depends on whether the model's been validated.  If NASA or
>>>> SpaceX say it I'll buy it--they both have track records of
>>>> producing models that predict what their hardware will do to
>>>> a level that is adequate for interplanetary navigation
>>>> purposes.  Some random stranger on the Internet is another
>>>> story. 
>>>> 
>>>
>>>Just because you are unwilling or unable to do the math
>>>yourself doesn't mean the math is wrong.  Math is math.
>>>
>>
>>But math is not physics.  If the math does not accurately
>>describe the physics then the math is irrelevant.
>>
> 
> Sorry, but now.  If the math doesn't adequately describe the
> physics the PHYSICS is wrong.  You understand that physics is
> just theory based on math, right?
> 
>>
>>>
>>>We've had this debate a long, long time ago in the sci.space
>>>newsgroups.  The fact is that there are many stages which are
>>>theoretically capable of performing SSTO with minimal payload.
>>>
>>
>>According to you.
>>
> 
> According to pretty much everyone who knows anything about the
> field. Then there's you...
> 
>>
>>>
>>>No one has ever done it 
>>>because the cost to get that payload into orbit is typically
>>>higher than it would be if you just used a smaller TSTO (or
>>>higher number of stages).  In other words, it just makes no
>>>sense to fly a disposable SSTO.  That and the "serious" space
>>>organizations just wouldn't do anything like this.  They've
>>>lost the drive to do anything innovative like this.
>>>
>>>Now a *reusable* SSTO is a whole other kettle of fish.  I'd
>>>imagine that we'll see BFS do an SSTO flight.  Why?  #1 because
>>>it will be reusable, so the cost of the flight will be a small
>>>multiplier on top of the propellant costs.  #2 it would be a
>>>useful test flight since BFS will be tested before the BFR
>>>first stage.  #3 because Elon Musk likes to do things that
>>>promote his products in a highly visible way.  To be the first
>>>to launch an land a reusable SSTO will be one for the record
>>>books for sure.  #4 Musk has already said that BFS will be SSTO
>>>capable. 
>>>
>>
>>Musk says a lot of things.  Some of them turn out to be true.
>>
> 
> Ah, the old "if he doesn't agree with me he's lying" fallacy. 
> He's made billions of dollars being 'wrong'.  What have you made
> being 'right'?
> 
He's made a lot of money being right about things. The trick if 
figuring out precisely what those things are. It's not a given that 
they are what his various companies *say* they are all about. He 
appears, to me, to be far better at attracting money from investors 
than he is at delivering products. Yeah, SpaceX is successful so 
far, but it would never have happened without taxpayer dollars, and 
a desperate need for alternate launch systems that aren't Russian. 
His other companies . . . are having rather more mixed results. For 
instance, Tesla is now being sued for securities fraud because . . 
. they made some claims about their ability to mass produce the 
Model X that turned out to . . . not be true.

-- 
Terry Austin

"Terry Austin: like the polio vaccine, only with more asshole."
    -- David Bilek

Jesus forgives sinners, not criminals.

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#689141 — Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?)

In article <rsbehdt4ta6d8oec8i67pp84muijlea8jl@4ax.com>, jclarke.873638
@gmail.com says...
> >
> >Just because you are unwilling or unable to do the math yourself doesn't 
> >mean the math is wrong.  Math is math.
> 
> But math is not physics.  If the math does not accurately describe the
> physics then the math is irrelevant.

Fine, then you don't understand the physics involved.  Got it.

> >We've had this debate a long, long time ago in the sci.space newsgroups.  
> >The fact is that there are many stages which are theoretically capable 
> >of performing SSTO with minimal payload.
> 
> According to you.

According to pretty much anyone who's run the simulations which is quite 
a few people.
 
> >No one has ever done it 
> >because the cost to get that payload into orbit is typically higher than 
> >it would be if you just used a smaller TSTO (or higher number of 
> >stages).  In other words, it just makes no sense to fly a disposable 
> >SSTO.  That and the "serious" space organizations just wouldn't do 
> >anything like this.  They've lost the drive to do anything innovative 
> >like this.
> >
> >Now a *reusable* SSTO is a whole other kettle of fish.  I'd imagine that 
> >we'll see BFS do an SSTO flight.  Why?  #1 because it will be reusable, 
> >so the cost of the flight will be a small multiplier on top of the 
> >propellant costs.  #2 it would be a useful test flight since BFS will be 
> >tested before the BFR first stage.  #3 because Elon Musk likes to do 
> >things that promote his products in a highly visible way.  To be the 
> >first to launch an land a reusable SSTO will be one for the record books 
> >for sure.  #4 Musk has already said that BFS will be SSTO capable.
> 
> Musk says a lot of things.  Some of them turn out to be true.

Agreed.  And if BFR/BFS is half as good as Musk says it will be, it will 
still revolutionize the launch industry well beyond what Falcon has 
done.  And for a point of reference, Falcon currently has 60% of the 
world's commercial launch market.  They'll pretty much have worked 
through their substantial backlog by the end of this year and their 
number of launches will actually drop in 2019 because of it.  

No other company or government on this planet can launch satellites 
cheaper than SpaceX.
 
> >So, we shall see.  

Thanks for leaving my last statement.  

Jeff 
-- 
All opinions posted by me on Usenet News are mine, and mine alone.  
These posts do not reflect the opinions of my family, friends, 
employer, or any organization that I am a member of.

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

#689263 — Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?)

On Wed, 6 Jun 2018 06:50:15 -0400, Jeff Findley
<jfindley@cinci.nospam.rr.com> wrote:

>In article <rsbehdt4ta6d8oec8i67pp84muijlea8jl@4ax.com>, jclarke.873638
>@gmail.com says...
>> >
>> >Just because you are unwilling or unable to do the math yourself doesn't 
>> >mean the math is wrong.  Math is math.
>> 
>> But math is not physics.  If the math does not accurately describe the
>> physics then the math is irrelevant.
>
>Fine, then you don't understand the physics involved.  Got it.

So anyone who recognizes that math is not physics "doesn't understand
the physics"?  Is that your argument?

>> >We've had this debate a long, long time ago in the sci.space newsgroups.  
>> >The fact is that there are many stages which are theoretically capable 
>> >of performing SSTO with minimal payload.
>> 
>> According to you.
>
>According to pretty much anyone who's run the simulations which is quite 
>a few people.

Run _which_ simulations?  Tell us of someone who has "run the
simulations" using code that has been used in the performance
calculations that resulted in an actual payload being delivered to
orbit.

>> >No one has ever done it 
>> >because the cost to get that payload into orbit is typically higher than 
>> >it would be if you just used a smaller TSTO (or higher number of 
>> >stages).  In other words, it just makes no sense to fly a disposable 
>> >SSTO.  That and the "serious" space organizations just wouldn't do 
>> >anything like this.  They've lost the drive to do anything innovative 
>> >like this.
>> >
>> >Now a *reusable* SSTO is a whole other kettle of fish.  I'd imagine that 
>> >we'll see BFS do an SSTO flight.  Why?  #1 because it will be reusable, 
>> >so the cost of the flight will be a small multiplier on top of the 
>> >propellant costs.  #2 it would be a useful test flight since BFS will be 
>> >tested before the BFR first stage.  #3 because Elon Musk likes to do 
>> >things that promote his products in a highly visible way.  To be the 
>> >first to launch an land a reusable SSTO will be one for the record books 
>> >for sure.  #4 Musk has already said that BFS will be SSTO capable.
>> 
>> Musk says a lot of things.  Some of them turn out to be true.
>
>Agreed.  And if BFR/BFS is half as good as Musk says it will be, it will 
>still revolutionize the launch industry well beyond what Falcon has 
>done.  And for a point of reference, Falcon currently has 60% of the 
>world's commercial launch market.  They'll pretty much have worked 
>through their substantial backlog by the end of this year and their 
>number of launches will actually drop in 2019 because of it.  

None of which is relevant to the point under discussion.

>No other company or government on this planet can launch satellites 
>cheaper than SpaceX.
> 
>> >So, we shall see.  
>
>Thanks for leaving my last statement.  

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#689269 — Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?)

J. Clarke <jclarke.873638@gmail.com> wrote on Wed, 06 Jun 2018
20:54:31 -0400:

>On Wed, 6 Jun 2018 06:50:15 -0400, Jeff Findley
><jfindley@cinci.nospam.rr.com> wrote:
>
>>In article <rsbehdt4ta6d8oec8i67pp84muijlea8jl@4ax.com>, jclarke.873638
>>@gmail.com says...
>>> >
>>> >Just because you are unwilling or unable to do the math yourself doesn't 
>>> >mean the math is wrong.  Math is math.
>>> 
>>> But math is not physics.  If the math does not accurately describe the
>>> physics then the math is irrelevant.
>>
>>Fine, then you don't understand the physics involved.  Got it.
>
>So anyone who recognizes that math is not physics "doesn't understand
>the physics"?  Is that your argument?
>

No, I think his 'argument' is that anyone who doesn't realize that
physics is based on math is not a physicist.

>>> >We've had this debate a long, long time ago in the sci.space newsgroups.  
>>> >The fact is that there are many stages which are theoretically capable 
>>> >of performing SSTO with minimal payload.
>>> 
>>> According to you.
>>
>>According to pretty much anyone who's run the simulations which is quite 
>>a few people.
>>
>
>Run _which_ simulations?  Tell us of someone who has "run the
>simulations" using code that has been used in the performance
>calculations that resulted in an actual payload being delivered to
>orbit.
>

Simulations don't 'deliver payload to orbit', so you're back to your
argument that because no one ever wasted the money to do it that it's
not possible.

>>> >No one has ever done it 
>>> >because the cost to get that payload into orbit is typically higher than 
>>> >it would be if you just used a smaller TSTO (or higher number of 
>>> >stages).  In other words, it just makes no sense to fly a disposable 
>>> >SSTO.  That and the "serious" space organizations just wouldn't do 
>>> >anything like this.  They've lost the drive to do anything innovative 
>>> >like this.
>>> >
>>> >Now a *reusable* SSTO is a whole other kettle of fish.  I'd imagine that 
>>> >we'll see BFS do an SSTO flight.  Why?  #1 because it will be reusable, 
>>> >so the cost of the flight will be a small multiplier on top of the 
>>> >propellant costs.  #2 it would be a useful test flight since BFS will be 
>>> >tested before the BFR first stage.  #3 because Elon Musk likes to do 
>>> >things that promote his products in a highly visible way.  To be the 
>>> >first to launch an land a reusable SSTO will be one for the record books 
>>> >for sure.  #4 Musk has already said that BFS will be SSTO capable.
>>> 
>>> Musk says a lot of things.  Some of them turn out to be true.
>>
>>Agreed.  And if BFR/BFS is half as good as Musk says it will be, it will 
>>still revolutionize the launch industry well beyond what Falcon has 
>>done.  And for a point of reference, Falcon currently has 60% of the 
>>world's commercial launch market.  They'll pretty much have worked 
>>through their substantial backlog by the end of this year and their 
>>number of launches will actually drop in 2019 because of it.  
>>
>
>None of which is relevant to the point under discussion.
>

The only 'point' here appears to be atop your head.


-- 
"Ignorance is preferable to error, and he is less remote from the
 truth who believes nothing than he who believes what is wrong."
                               -- Thomas Jefferson

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#689310 — Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?)

I took the sci-fi groups out of this follow-up.  Perhaps that will 
improve the signal to noise ratio of the follow-ups.

In article <4a0hhdt4adhs136u0aqtd1klsd38ieo6qc@4ax.com>, jclarke.873638
@gmail.com says...
> 
> On Wed, 6 Jun 2018 06:50:15 -0400, Jeff Findley
> <jfindley@cinci.nospam.rr.com> wrote:
> 
> >In article <rsbehdt4ta6d8oec8i67pp84muijlea8jl@4ax.com>, jclarke.873638
> >@gmail.com says...
> >> >
> >> >Just because you are unwilling or unable to do the math yourself doesn't 
> >> >mean the math is wrong.  Math is math.
> >> 
> >> But math is not physics.  If the math does not accurately describe the
> >> physics then the math is irrelevant.
> >
> >Fine, then you don't understand the physics involved.  Got it.
> 
> So anyone who recognizes that math is not physics "doesn't understand
> the physics"?  Is that your argument?

The simulations which have been run accurately describe the physics of 
launch vehicles.  This isn't "bleeding edge technology".  This is 
something that we've been modeling for well over half a century.

> >> >We've had this debate a long, long time ago in the sci.space newsgroups.  
> >> >The fact is that there are many stages which are theoretically capable 
> >> >of performing SSTO with minimal payload.
> >> 
> >> According to you.
> >
> >According to pretty much anyone who's run the simulations which is quite 
> >a few people.
> 
> Run _which_ simulations?  Tell us of someone who has "run the
> simulations" using code that has been used in the performance
> calculations that resulted in an actual payload being delivered to
> orbit.

This has been discussed at length in the sci.space newsgroups, but it's 
likely been decades since the topic came up.  But the physics hasn't 
changed one bit.  Try searching back in the sci.space newsgroup.  Or try 
Google.  
 
> >> >No one has ever done it 
> >> >because the cost to get that payload into orbit is typically higher than 
> >> >it would be if you just used a smaller TSTO (or higher number of 
> >> >stages).  In other words, it just makes no sense to fly a disposable 
> >> >SSTO.  That and the "serious" space organizations just wouldn't do 
> >> >anything like this.  They've lost the drive to do anything innovative 
> >> >like this.
> >> >
> >> >Now a *reusable* SSTO is a whole other kettle of fish.  I'd imagine that 
> >> >we'll see BFS do an SSTO flight.  Why?  #1 because it will be reusable, 
> >> >so the cost of the flight will be a small multiplier on top of the 
> >> >propellant costs.  #2 it would be a useful test flight since BFS will be 
> >> >tested before the BFR first stage.  #3 because Elon Musk likes to do 
> >> >things that promote his products in a highly visible way.  To be the 
> >> >first to launch an land a reusable SSTO will be one for the record books 
> >> >for sure.  #4 Musk has already said that BFS will be SSTO capable.
> >> 
> >> Musk says a lot of things.  Some of them turn out to be true.
> >
> >Agreed.  And if BFR/BFS is half as good as Musk says it will be, it will 
> >still revolutionize the launch industry well beyond what Falcon has 
> >done.  And for a point of reference, Falcon currently has 60% of the 
> >world's commercial launch market.  They'll pretty much have worked 
> >through their substantial backlog by the end of this year and their 
> >number of launches will actually drop in 2019 because of it.  
> 
> None of which is relevant to the point under discussion.

BFS will almost surely demonstrate itself as an SSTO as part of its 
testing.  I don't see how this isn't relevant.
 
Again, expendable SSTOs are physically possible, they're just not 
economical.  BFS, being reusable, changes that equation.

Jeff
-- 
All opinions posted by me on Usenet News are mine, and mine alone.  
These posts do not reflect the opinions of my family, friends, 
employer, or any organization that I am a member of.

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#689131 — Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?)

Jeff Findley <jfindley@cinci.nospam.rr.com> schrieb:

> We've had this debate a long, long time ago in the sci.space newsgroups.  
> The fact is that there are many stages which are theoretically capable 
> of performing SSTO with minimal payload.  No one has ever done it 
> because the cost to get that payload into orbit is typically higher than 
> it would be if you just used a smaller TSTO (or higher number of 
> stages).  In other words, it just makes no sense to fly a disposable 
> SSTO.

There are also other considerations to take into account.

One of them is mechanical. A first stage flying with a much smaller
payload than the current second stage + actual payload would
have much lower mass towards the end of the burn, resulting in
higher acceleration and higher mechanical stress.  Buckling could
be something that needed to to be guarded against, as could be
outright failure due to compression stress.

Possible solutions if it turns out to be a problem:

Turn down the engine thrust (How far is that possible? Can the
engines even do that? What will it do to the specific impulse?)
or switch off individual engines (what happens if you swith off
one half a second later than the others?).

Strenghten the strucutre. This would add mass, and it would not
be the same first stage anymore.

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#689136 — Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?)

Thomas Koenig <tkoenig@netcologne.de> wrote on Wed, 6 Jun 2018
06:21:34 -0000 (UTC):

>Jeff Findley <jfindley@cinci.nospam.rr.com> schrieb:
>
>> We've had this debate a long, long time ago in the sci.space newsgroups.  
>> The fact is that there are many stages which are theoretically capable 
>> of performing SSTO with minimal payload.  No one has ever done it 
>> because the cost to get that payload into orbit is typically higher than 
>> it would be if you just used a smaller TSTO (or higher number of 
>> stages).  In other words, it just makes no sense to fly a disposable 
>> SSTO.
>
>There are also other considerations to take into account.
>
>One of them is mechanical. A first stage flying with a much smaller
>payload than the current second stage + actual payload would
>have much lower mass towards the end of the burn, resulting in
>higher acceleration and higher mechanical stress.  Buckling could
>be something that needed to to be guarded against, as could be
>outright failure due to compression stress.
>

If you're going for orbit you're well out of the atmosphere at the
'end of the burn'.  Neither of those are an issue.

>Possible solutions if it turns out to be a problem:
>
>Turn down the engine thrust (How far is that possible? Can the
>engines even do that? What will it do to the specific impulse?)
>or switch off individual engines (what happens if you swith off
>one half a second later than the others?).
>

Of course it's possible.  What do you think they do approaching max Q
now?  It doesn't do anything to specific impulse (do you know what
that means)?  It just means the engine burns longer.

>
>Strenghten the strucutre. This would add mass, and it would not
>be the same first stage anymore.
>

Stress on the first stage is probably higher with all that mass
mounted on it than it would be otherwise.


-- 
"Some people get lost in thought because it's such unfamiliar
 territory."
                                      --G. Behn

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#689142 — Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?)

In article <pf7uhe$e5c$1@newsreader5.netcologne.de>, 
tkoenig@netcologne.de says...
> 
> Jeff Findley <jfindley@cinci.nospam.rr.com> schrieb:
> 
> > We've had this debate a long, long time ago in the sci.space newsgroups.  
> > The fact is that there are many stages which are theoretically capable 
> > of performing SSTO with minimal payload.  No one has ever done it 
> > because the cost to get that payload into orbit is typically higher than 
> > it would be if you just used a smaller TSTO (or higher number of 
> > stages).  In other words, it just makes no sense to fly a disposable 
> > SSTO.
> 
> There are also other considerations to take into account.
> 
> One of them is mechanical. A first stage flying with a much smaller
> payload than the current second stage + actual payload would
> have much lower mass towards the end of the burn, resulting in
> higher acceleration and higher mechanical stress.  Buckling could
> be something that needed to to be guarded against, as could be
> outright failure due to compression stress.

That's a solved problem.  
 
> Possible solutions if it turns out to be a problem:
> 
> Turn down the engine thrust (How far is that possible? Can the
> engines even do that? What will it do to the specific impulse?)
> or switch off individual engines (what happens if you swith off
> one half a second later than the others?).

If you have multiple engines, yes you shut a few down to keep the Gs 
under control.  It's quite easy to shut down a liquid fueled rocket 
engine in a controlled manner.  This isn't an issue.

If you still have too high of a thrust near the end of the burn, you 
need an engine that you can throttle.  Yes you can lose some performance 
by doing this, but you can design the engine to minimize this (e.g. the 
SSME had a crazy high chamber pressure to begin with, so when it was 
throttled, you didn't run into huge problems like flow separation and 
the like).  

Note that Falcon 9, the first stage that sparked this conversation, has 
both options available to it.  Merlin can throttle (it does so on every 
flight by throttling down a bit at max-Q).  And, the Falcon 9 first 
stage has 9 engines total.  You can easily shut them down in pairs to 
keep the thrust "balanced".  And since it has one engine in the center, 
it can run on as few as one engine.  

For a Falcon 9 based SSTO, you might not even need all 9 of those 
engines at all.  An "optimized" Falcon 9 based SSTO might be able to 
delete a pair or two of engines to save mass and lengthen the burn time 
to make orbit.
 
> Strenghten the strucutre. This would add mass, and it would not
> be the same first stage anymore.

It's already overbuilt for the SSTO role since it won't be carrying the 
mass of an upper stage or as massive of a payload.  So "strengthening 
the stage" beyond that really isn't necessary.

Jeff
-- 
All opinions posted by me on Usenet News are mine, and mine alone.  
These posts do not reflect the opinions of my family, friends, 
employer, or any organization that I am a member of.

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#689313 — Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?)

Jeff Findley <jfindley@cinci.nospam.rr.com> schrieb:
> In article <pf7uhe$e5c$1@newsreader5.netcologne.de>, 
> tkoenig@netcologne.de says...
>> 
>> Jeff Findley <jfindley@cinci.nospam.rr.com> schrieb:
>> 
>> > We've had this debate a long, long time ago in the sci.space newsgroups.  
>> > The fact is that there are many stages which are theoretically capable 
>> > of performing SSTO with minimal payload.  No one has ever done it 
>> > because the cost to get that payload into orbit is typically higher than 
>> > it would be if you just used a smaller TSTO (or higher number of 
>> > stages).  In other words, it just makes no sense to fly a disposable 
>> > SSTO.
>> 
>> There are also other considerations to take into account.
>> 
>> One of them is mechanical. A first stage flying with a much smaller
>> payload than the current second stage + actual payload would
>> have much lower mass towards the end of the burn, resulting in
>> higher acceleration and higher mechanical stress.  Buckling could
>> be something that needed to to be guarded against, as could be
>> outright failure due to compression stress.
>
> That's a solved problem.  

It is a problem which can be solved, at a possible cost to
performance (added mass).

I doubt it has been solved for all of the "many stages" you
mentioned.  That would have been counterproductive to the
primary mission, and would probably have been regarded as
an error.

Can you elaborate which stages this was solved for, how, why,
and where you got the info from?

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#689346 — Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?)

Thomas Koenig <tkoenig@netcologne.de> wrote on Thu, 7 Jun 2018
16:42:38 -0000 (UTC):

>Jeff Findley <jfindley@cinci.nospam.rr.com> schrieb:
>> In article <pf7uhe$e5c$1@newsreader5.netcologne.de>, 
>> tkoenig@netcologne.de says...
>>> 
>>> Jeff Findley <jfindley@cinci.nospam.rr.com> schrieb:
>>> 
>>> > We've had this debate a long, long time ago in the sci.space newsgroups.  
>>> > The fact is that there are many stages which are theoretically capable 
>>> > of performing SSTO with minimal payload.  No one has ever done it 
>>> > because the cost to get that payload into orbit is typically higher than 
>>> > it would be if you just used a smaller TSTO (or higher number of 
>>> > stages).  In other words, it just makes no sense to fly a disposable 
>>> > SSTO.
>>> 
>>> There are also other considerations to take into account.
>>> 
>>> One of them is mechanical. A first stage flying with a much smaller
>>> payload than the current second stage + actual payload would
>>> have much lower mass towards the end of the burn, resulting in
>>> higher acceleration and higher mechanical stress.  Buckling could
>>> be something that needed to to be guarded against, as could be
>>> outright failure due to compression stress.
>>
>> That's a solved problem.  
>
>It is a problem which can be solved, at a possible cost to
>performance (added mass).
>
>I doubt it has been solved for all of the "many stages" you
>mentioned.  That would have been counterproductive to the
>primary mission, and would probably have been regarded as
>an error.
>
>Can you elaborate which stages this was solved for, how, why,
>and where you got the info from?
>

Stress is higher on the first stage structure when there is a big mass
sitting on top of it than when there is not.  If it can stand the
stress of launch with a second stage and payload, it can stand the
stress of launch without them.


-- 
"Ignorance is preferable to error, and he is less remote from the
 truth who believes nothing than he who believes what is wrong."
                               -- Thomas Jefferson

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#689941 — Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?)

The cancelling of the DC-X and X-33 programs were premature. Even if they 
did not lead to successful SSTO's, they could have themselves been used as 
reusable first stages to cut the cost to orbit to the $2,000 per kilo, or 
$1,000 per pound, range.

Saturday, October 5, 2013
DARPA's Spaceplane: an X-33 version.
http://exoscientist.blogspot.com/2013/10/darpas-spaceplane-x-33-version.html

The planned satellite megaconstellations may finally provide a launch market 
to make reusable launchers financially viable. DARPA's reusable spaceplane 
booster stage is to have a test flight in 2020. But in fact the famous X-33 
could have fulfilled this role before it was cancelled in 2000 by switching 
from carbon composite tanks to aluminum-lithium tanks.

Space advocates will recall the X-33 was cancelled when its carbon composite 
propellant tanks failed. But there may now be high strength aluminum alloys 
that can fill that role. Then in fact the SSTO VentureStar may now be 
possible:

DARPA's Spaceplane: an X-33 version, Page 2.
https://exoscientist.blogspot.com/2018/06/darpas-spaceplane-x-33-version-page-2.html

  Bob Clark


------------------------------------------------------------------
Single-stage-to-orbit was already shown possible 50 years ago
with the Titan II first stage.
In fact, contrary to popular belief SSTO's are actually easy.
Just use the most efficient engines and stages at the same time,
and the result will automatically be SSTO.
Blog: Http://Exoscientist.blogspot.com
------------------------------------------------------------------ 

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#689965 — Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?)

"Robert Clark" <rgregoryclark@gmSPAMBLOCKail.com> wrote on Sun, 10 Jun
2018 20:16:21 -0400:

>
>The cancelling of the DC-X and X-33 programs were premature. 
>

Probably.

>
>Even if they 
>did not lead to successful SSTO's, they could have themselves been used as 
>reusable first stages to cut the cost to orbit to the $2,000 per kilo, or 
>$1,000 per pound, range.
>

Utter poppycock.


-- 
"The reasonable man adapts himself to the world; the unreasonable 
 man persists in trying to adapt the world to himself. Therefore, 
 all progress depends on the unreasonable man."
                                      --George Bernard Shaw

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#688684 — Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?)

J. Clarke <jclarke.873638@gmail.com> writes:
>On Sun, 03 Jun 2018 14:06:20 -0700, Fred J. McCall
><fjmccall@gmail.com> wrote:
>

>>>
>>>I don't believe what I want to.  I believe what is true.  
>>>
>>
>>Oh, do you now?  Why is what you want to believe "true" with no proof?
>
>I believe that it is true that no SSTO has ever made it to orbit.

For what it's worth, a friend of mine at micky d's in the 90's claimed
the clipper (DC-X) actually made a couple of military flights SSTO.  FWIW.

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#688766 — Re: Once more into the breach: SSTO's (was Re: Life on Europa in scifi?)

scott@slp53.sl.home (Scott Lurndal) wrote on Mon, 04 Jun 2018 15:40:58
GMT:

>J. Clarke <jclarke.873638@gmail.com> writes:
>>On Sun, 03 Jun 2018 14:06:20 -0700, Fred J. McCall
>><fjmccall@gmail.com> wrote:
>>
>
>>>>
>>>>I don't believe what I want to.  I believe what is true.  
>>>>
>>>
>>>Oh, do you now?  Why is what you want to believe "true" with no proof?
>>
>>I believe that it is true that no SSTO has ever made it to orbit.
>
>For what it's worth, a friend of mine at micky d's in the 90's claimed
>the clipper (DC-X) actually made a couple of military flights SSTO.  FWIW.
>

DC-X wasn't capable of orbit.  This is why the program needed to
continue with DC-Y and Delta Clipper.


-- 
"Ignorance is preferable to error, and he is less remote from the
 truth who believes nothing than he who believes what is wrong."
                               -- Thomas Jefferson

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