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Groups > sci.physics > #689363 > unrolled thread
| Started by | "Robert Clark" <rgregoryclark@gmSPAMBLOCKail.com> |
|---|---|
| First post | 2018-06-07 16:24 -0400 |
| Last post | 2018-06-18 15:38 -0700 |
| Articles | 20 on this page of 130 — 16 participants |
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Towards routine, reusable space launch. "Robert Clark" <rgregoryclark@gmSPAMBLOCKail.com> - 2018-06-07 16:24 -0400
Re: Towards routine, reusable space launch. "Robert Clark" <rgregoryclark@gmSPAMBLOCKail.com> - 2018-06-07 16:47 -0400
Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-07 23:24 -0700
Re: Towards routine, reusable space launch. Doc O'Leary <droleary@2017usenet1.subsume.com> - 2018-06-08 13:10 +0000
Re: Towards routine, reusable space launch. Sergio <invalid@invalid.com> - 2018-06-08 08:31 -0500
Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-08 20:47 -0700
Re: Towards routine, reusable space launch. Doc O'Leary <droleary@2017usenet1.subsume.com> - 2018-06-09 17:19 +0000
Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-09 16:02 -0400
Re: Towards routine, reusable space launch. Doc O'Leary <droleary@2017usenet1.subsume.com> - 2018-06-11 03:16 +0000
Re: Towards routine, reusable space launch. Sergio <invalid@invalid.com> - 2018-06-10 23:19 -0500
Re: Towards routine, reusable space launch. Thomas Koenig <tkoenig@netcologne.de> - 2018-06-11 05:25 +0000
Re: Towards routine, reusable space launch. Doc O'Leary <droleary@2017usenet1.subsume.com> - 2018-06-11 22:18 +0000
Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-11 20:52 -0700
Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-12 06:34 -0400
Re: Towards routine, reusable space launch. Doc O'Leary <droleary@2017usenet1.subsume.com> - 2018-06-12 14:36 +0000
Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-12 14:29 -0700
Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-12 19:00 -0400
Re: Towards routine, reusable space launch. JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-13 02:15 -0400
Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-13 01:27 -0700
Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-13 06:46 -0400
Re: Towards routine, reusable space launch. JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-13 16:28 -0400
Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-13 14:38 -0700
Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-14 05:22 -0400
Re: Towards routine, reusable space launch. JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-14 15:44 -0400
Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-15 07:52 -0400
Re: Towards routine, reusable space launch. JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-15 21:33 -0400
Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-16 10:38 -0400
Re: Towards routine, reusable space launch. JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-16 17:51 -0400
Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-17 02:16 -0700
Re: Towards routine, reusable space launch. JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-17 15:49 -0400
Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-17 16:52 -0400
Re: Towards routine, reusable space launch. JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-18 02:44 -0400
Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-18 00:05 -0700
Re: Towards routine, reusable space launch. JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-18 14:27 -0400
Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-18 19:39 -0700
Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-17 18:26 -0700
Re: Towards routine, reusable space launch. Doc O'Leary <droleary@2017usenet1.subsume.com> - 2018-06-13 12:57 +0000
Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-13 14:35 -0700
Re: Towards routine, reusable space launch. JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-13 17:55 -0400
Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-13 21:44 -0700
Re: Towards routine, reusable space launch. Doc O'Leary <droleary@2017usenet1.subsume.com> - 2018-06-14 22:02 +0000
Re: Towards routine, reusable space launch. Alain Fournier <alain245@videotron.ca> - 2018-06-13 19:39 -0400
Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-13 21:53 -0700
Re: Towards routine, reusable space launch. Alain Fournier <alain245@videotron.ca> - 2018-06-14 19:46 -0400
Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-15 07:56 -0400
Re: Towards routine, reusable space launch. Alain Fournier <alain245@videotron.ca> - 2018-06-15 19:21 -0400
Re: Towards routine, reusable space launch. Sergio <invalid@invalid.com> - 2018-06-15 19:18 -0500
Re: Towards routine, reusable space launch. Alain Fournier <alain245@videotron.ca> - 2018-06-15 21:05 -0400
Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-16 10:06 -0400
Re: Towards routine, reusable space launch. Alain Fournier <alain245@videotron.ca> - 2018-06-16 13:21 -0400
Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-16 13:57 -0400
Re: Towards routine, reusable space launch. Alain Fournier <alain245@videotron.ca> - 2018-06-16 14:19 -0400
Re: Towards routine, reusable space launch. mvp@web1.calweb.com (Mike Van Pelt) - 2018-06-19 18:38 +0000
Re: Towards routine, reusable space launch. Greg Goss <gossg@gossg.org> - 2018-06-19 21:27 -0600
Re: Towards routine, reusable space launch. JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-15 22:13 -0400
Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-15 20:34 -0700
Re: Towards routine, reusable space launch. Alain Fournier <alain245@videotron.ca> - 2018-06-16 09:54 -0400
Re: Towards routine, reusable space launch. Sergio <invalid@invalid.com> - 2018-06-18 13:45 -0500
Re: Towards routine, reusable space launch. Alain Fournier <alain245@videotron.ca> - 2018-06-18 21:06 -0400
Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-18 20:00 -0700
Re: Towards routine, reusable space launch. Alain Fournier <alain245@videotron.ca> - 2018-06-19 19:45 -0400
Re: Towards routine, reusable space launch. JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-19 22:12 -0400
Re: Towards routine, reusable space launch. Alain Fournier <alain245@videotron.ca> - 2018-06-20 20:21 -0400
Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-20 17:13 -0700
Re: Towards routine, reusable space launch. Alain Fournier <alain245@videotron.ca> - 2018-06-20 20:34 -0400
Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-21 06:26 -0400
Re: Towards routine, reusable space launch. Steve Carroll <frelwizzen@gmail.com> - 2018-06-21 03:48 -0700
Re: Towards routine, reusable space launch. JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-21 13:35 -0400
Re: Towards routine, reusable space launch. Alain Fournier <alain245@videotron.ca> - 2018-06-21 20:57 -0400
Re: Towards routine, reusable space launch. Sergio <invalid@invalid.com> - 2018-06-21 23:22 -0500
Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-22 07:18 -0400
Re: Towards routine, reusable space launch. JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-22 17:45 -0400
Re: Towards routine, reusable space launch. Alain Fournier <alain245@videotron.ca> - 2018-06-22 19:58 -0400
Re: Towards routine, reusable space launch. JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-23 03:39 -0400
Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-23 08:38 -0400
Re: Towards routine, reusable space launch. JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-23 17:18 -0400
Re: Towards routine, reusable space launch. Alain Fournier <alain245@videotron.ca> - 2018-06-23 09:58 -0400
Re: Towards routine, reusable space launch. Sergio <invalid@invalid.com> - 2018-06-24 00:53 -0500
Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-23 08:34 -0400
Re: Towards routine, reusable space launch. Sergio <invalid@invalid.com> - 2018-06-18 22:17 -0500
Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-19 00:45 -0700
Re: Towards routine, reusable space launch. Sergio <invalid@invalid.com> - 2018-06-19 15:58 -0500
Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-19 14:38 -0700
Re: Towards routine, reusable space launch. Sergio <invalid@invalid.com> - 2018-06-20 15:42 -0500
Re: Towards routine, reusable space launch. JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-06-20 16:58 -0400
Re: Towards routine, reusable space launch. Thomas Koenig <tkoenig@netcologne.de> - 2018-06-25 20:44 +0000
Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-20 17:07 -0700
Re: Towards routine, reusable space launch. Sergio <invalid@invalid.com> - 2018-06-21 23:24 -0500
Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-21 21:38 -0700
Re: Towards routine, reusable space launch. Greg Goss <gossg@gossg.org> - 2018-06-19 21:35 -0600
Re: Towards routine, reusable space launch. Thomas Koenig <tkoenig@netcologne.de> - 2018-06-19 17:01 +0000
Re: Towards routine, reusable space launch. Sergio <invalid@invalid.com> - 2018-06-21 22:39 -0500
Re: Towards routine, reusable space launch. "reber G=emc^2" <herbertglazier0@gmail.com> - 2018-06-14 15:39 -0700
Re: Towards routine, reusable space launch. "hanson" <hanson@quick.net> - 2018-06-14 15:53 -0700
Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-14 04:47 -0400
Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-11 04:00 -0700
Re: Towards routine, reusable space launch. Doc O'Leary <droleary@2017usenet1.subsume.com> - 2018-06-11 22:35 +0000
Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-11 20:58 -0700
Re: Towards routine, reusable space launch. Doc O'Leary <droleary@2017usenet1.subsume.com> - 2018-06-12 15:00 +0000
Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-12 14:36 -0700
Re: Towards routine, reusable space launch. Alain Fournier <alain245@videotron.ca> - 2018-06-12 20:08 -0400
Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-12 22:12 -0700
Re: Towards routine, reusable space launch. willner@cfa.harvard.edu (Steve Willner) - 2018-06-15 18:59 +0000
Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-15 12:13 -0700
Re: Towards routine, reusable space launch. willner@cfa.harvard.edu (Steve Willner) - 2018-06-18 20:36 +0000
Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-18 19:57 -0700
Re: Towards routine, reusable space launch. willner@cfa.harvard.edu (Steve Willner) - 2018-06-25 21:17 +0000
Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-25 15:52 -0700
Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-11 07:49 -0400
Re: Towards routine, reusable space launch. Thomas Koenig <tkoenig@netcologne.de> - 2018-06-11 16:36 +0000
Re: Towards routine, reusable space launch. Sergio <invalid@invalid.com> - 2018-06-11 14:02 -0500
Re: Towards routine, reusable space launch. benj <benj@nobody.net> - 2018-06-11 17:23 -0400
Re: Towards routine, reusable space launch. Sergio <invalid@invalid.com> - 2018-06-11 21:20 -0500
Re: Towards routine, reusable space launch. Greg Goss <gossg@gossg.org> - 2018-06-11 19:38 -0600
Re: Towards routine, reusable space launch. Doc O'Leary <droleary@2017usenet1.subsume.com> - 2018-06-11 22:50 +0000
Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-11 21:03 -0700
Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-12 06:44 -0400
Re: Towards routine, reusable space launch. Sergio <invalid@invalid.com> - 2018-06-12 09:57 -0500
Re: Towards routine, reusable space launch. benj <benj@nobody.net> - 2018-06-12 17:52 -0400
Re: Towards routine, reusable space launch. Doc O'Leary <droleary@2017usenet1.subsume.com> - 2018-06-12 15:20 +0000
Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-12 14:47 -0700
Re: Towards routine, reusable space launch. Thomas Koenig <tkoenig@netcologne.de> - 2018-06-12 19:43 +0000
Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-12 14:52 -0700
Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-12 16:05 -0700
Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-13 06:41 -0400
Re: Towards routine, reusable space launch. Fred J. McCall <fjmccall@gmail.com> - 2018-06-13 14:36 -0700
Re: Towards routine, reusable space launch. Greg Goss <gossg@gossg.org> - 2018-06-09 09:34 -0600
Re: Towards routine, reusable space launch. Jeff Findley <jfindley@cinci.nospam.rr.com> - 2018-06-09 15:56 -0400
Re: Towards routine, reusable space launch. "Robert Clark" <rgregoryclark@gmSPAMBLOCKail.com> - 2018-06-08 18:06 -0400
Re: Towards routine, reusable space launch. numbernumber1964@gmail.com - 2018-06-18 15:38 -0700
Page 6 of 7 — ← Prev page 1 2 3 4 5 [6] 7 Next page →
| From | Alain Fournier <alain245@videotron.ca> |
|---|---|
| Date | 2018-06-12 20:08 -0400 |
| Message-ID | <pfpn9a$ss8$1@dont-email.me> |
| In reply to | #690314 |
On Jun/12/2018 at 5:36 PM, Fred J. McCall wrote : > Doc O'Leary <droleary@2017usenet1.subsume.com> wrote on Tue, 12 Jun > 2018 15:00:13 -0000 (UTC): > >> For your reference, records indicate that >> Fred J. McCall <fjmccall@gmail.com> wrote: >> >>> Doc O'Leary <droleary@2017usenet1.subsume.com> wrote on Mon, 11 Jun >>> 2018 22:35:20 -0000 (UTC): >>> >>>> Chicken and egg. The fact is that we *do* sometimes have to >>>> elaborately engineer spacecraft in order to make them small enough to >>>> fit into a nose cone or payload bay of a rocket. >>>> >>> >>> Head and ass. Cite for such payloads? Be specific. You're posting >>> into a 'sci' newsgroup. Handwavium is not sufficient. >> >> Then I must say I note a lack of citations for your own claims. >> > > I haven't made any claims. > >> >> Mine >> are easy enough to demonstrate. I can literally link to just about >> *any* payload that unfolds to deploy as evidence. Let’s start with >> the obvious: >> >> <https://en.wikipedia.org/wiki/James_Webb_Space_Telescope#/media/File:JWST_launch_configuration.png> >> > > Not a good example. Things like solar arrays are launched folded > because they can't take acceleration without snapping off, not because > they're 'too bulky'. Try again? The telescope is folded, not only the solar arrays. Alain Fournier
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| From | Fred J. McCall <fjmccall@gmail.com> |
|---|---|
| Date | 2018-06-12 22:12 -0700 |
| Message-ID | <cs91idhasmjd9qbdhmk4qajkgr1u3jp7fg@4ax.com> |
| In reply to | #690351 |
Alain Fournier <alain245@videotron.ca> wrote on Tue, 12 Jun 2018
20:08:10 -0400:
>On Jun/12/2018 at 5:36 PM, Fred J. McCall wrote :
>> Doc O'Leary <droleary@2017usenet1.subsume.com> wrote on Tue, 12 Jun
>> 2018 15:00:13 -0000 (UTC):
>>
>>> For your reference, records indicate that
>>> Fred J. McCall <fjmccall@gmail.com> wrote:
>>>
>>>> Doc O'Leary <droleary@2017usenet1.subsume.com> wrote on Mon, 11 Jun
>>>> 2018 22:35:20 -0000 (UTC):
>>>>
>>>>> Chicken and egg. The fact is that we *do* sometimes have to
>>>>> elaborately engineer spacecraft in order to make them small enough to
>>>>> fit into a nose cone or payload bay of a rocket.
>>>>>
>>>>
>>>> Head and ass. Cite for such payloads? Be specific. You're posting
>>>> into a 'sci' newsgroup. Handwavium is not sufficient.
>>>
>>> Then I must say I note a lack of citations for your own claims.
>>>
>>
>> I haven't made any claims.
>>
>>>
>>> Mine
>>> are easy enough to demonstrate. I can literally link to just about
>>> *any* payload that unfolds to deploy as evidence. Let’s start with
>>> the obvious:
>>>
>>> <https://en.wikipedia.org/wiki/James_Webb_Space_Telescope#/media/File:JWST_launch_configuration.png>
>>>
>>
>> Not a good example. Things like solar arrays are launched folded
>> because they can't take acceleration without snapping off, not because
>> they're 'too bulky'. Try again?
>
>The telescope is folded, not only the solar arrays.
>
And THAT is because you cannot make a single mirror that large to
adequate precision, so once it's in pieces you might as well fold the
sucker up.
--
"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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| From | willner@cfa.harvard.edu (Steve Willner) |
|---|---|
| Date | 2018-06-15 18:59 +0000 |
| Message-ID | <pg129r$5ll$1@dont-email.me> |
| In reply to | #690379 |
> >The [JWST] telescope is folded, not only the solar arrays. In particular the 6.5-m primary mirror is folded as well as many other pieces. It's frightening to watch the deployment videos. In article <cs91idhasmjd9qbdhmk4qajkgr1u3jp7fg@4ax.com>, Fred J. McCall <fjmccall@gmail.com> writes: > And THAT is because you cannot make a single mirror that large to > adequate precision, At least three observatories with seven telescopes in active use will be surprised to learn that. Not to mention additional ones planned. Every JWST presentation I've seen that mentioned the subject said that using a deployable (folding) mirror is because the Ariane 5 shroud is too small to fit a 6.5-m mirror. I wouldn't be surprised if there are "black" programs with the same difficulty. That said, this particular use case doesn't necessarily justify a rockoon approach, which will be difficult at best for large boosters. -- Help keep our newsgroup healthy; please don't feed the trolls. Steve Willner Phone 617-495-7123 swillner@cfa.harvard.edu Cambridge, MA 02138 USA
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| From | Fred J. McCall <fjmccall@gmail.com> |
|---|---|
| Date | 2018-06-15 12:13 -0700 |
| Message-ID | <1q38id1rbuqh4k46gpk8o1m70o294nn3k8@4ax.com> |
| In reply to | #690740 |
willner@cfa.harvard.edu (Steve Willner) wrote on Fri, 15 Jun 2018
18:59:07 -0000 (UTC):
>> >The [JWST] telescope is folded, not only the solar arrays.
>
>In particular the 6.5-m primary mirror is folded as well as many
>other pieces. It's frightening to watch the deployment videos.
>
>In article <cs91idhasmjd9qbdhmk4qajkgr1u3jp7fg@4ax.com>,
> Fred J. McCall <fjmccall@gmail.com> writes:
>> And THAT is because you cannot make a single mirror that large to
>> adequate precision,
>
>At least three observatories with seven telescopes in active use will
>be surprised to learn that. Not to mention additional ones planned.
>
You can do things with earthbound scopes that you cannot do with
something you're going to shoot into space.
>
>Every JWST presentation I've seen that mentioned the subject said
>that using a deployable (folding) mirror is because the Ariane 5
>shroud is too small to fit a 6.5-m mirror. I wouldn't be surprised
>if there are "black" programs with the same difficulty.
>
Nope. They use a mirror roughly the size of Hubble's. Remember,
they're looking at something relatively close as such things go.
>
>That said, this particular use case doesn't necessarily justify a
>rockoon approach, which will be difficult at best for large boosters.
>
Yes. The point is that a balloon does NOT replace a 'first stage'.
--
"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
[toc] | [prev] | [next] | [standalone]
| From | willner@cfa.harvard.edu (Steve Willner) |
|---|---|
| Date | 2018-06-18 20:36 +0000 |
| Message-ID | <pg954i$pce$1@dont-email.me> |
| In reply to | #690741 |
> >At least three observatories with seven telescopes in active use will > >be surprised to learn [that making a 6.5-m primary mirror is impossible] That should have been five observatories and ten telescopes. I forgot some. I won't swear I'm not still forgetting others. In article <1q38id1rbuqh4k46gpk8o1m70o294nn3k8@4ax.com>, Fred J. McCall <fjmccall@gmail.com> writes: > You can do things with earthbound scopes that you cannot do with > something you're going to shoot into space. How does that apply to the current discussion? Launching a 6.5-m mirror monolithic should in principle be easier than having the same size mirror deploy to the required precision. The problem is making it fit into the payload fairing. > > I wouldn't be surprised if there are "black" programs with the > >same difficulty. > Nope. They use a mirror roughly the size of Hubble's. The ones we know about used mirrors that size. Anyone who actually knows the current situation -- I don't -- wouldn't be allowed to say. > Remember, they're looking at something relatively close as such > things go. 6.5-m mirrors would have advantages over smaller ones. (I don't see what distance has to do with anything.) I've seen hints that some have been built and deployed, but that may be salemanship. Companies vying for the JWST contract would have had an incentive to drop such hints whether true or not. > The point is that a balloon does NOT replace a 'first stage'. We agree on that. -- Help keep our newsgroup healthy; please don't feed the trolls. Steve Willner Phone 617-495-7123 swillner@cfa.harvard.edu Cambridge, MA 02138 USA
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| From | Fred J. McCall <fjmccall@gmail.com> |
|---|---|
| Date | 2018-06-18 19:57 -0700 |
| Message-ID | <2frgidh5cfamkc9f50i79cts222ho7t09j@4ax.com> |
| In reply to | #691105 |
willner@cfa.harvard.edu (Steve Willner) wrote on Mon, 18 Jun 2018
20:36:35 -0000 (UTC):
>> >At least three observatories with seven telescopes in active use will
>> >be surprised to learn [that making a 6.5-m primary mirror is impossible]
>
>That should have been five observatories and ten telescopes. I
>forgot some. I won't swear I'm not still forgetting others.
>
And you're still talking about earthbound scopes.
>In article <1q38id1rbuqh4k46gpk8o1m70o294nn3k8@4ax.com>,
> Fred J. McCall <fjmccall@gmail.com> writes:
>> You can do things with earthbound scopes that you cannot do with
>> something you're going to shoot into space.
>
>How does that apply to the current discussion? Launching a 6.5-m
>mirror monolithic should in principle be easier than having the same
>size mirror deploy to the required precision. The problem is making
>it fit into the payload fairing.
>
Oversize fairings are easy.
>> > I wouldn't be surprised if there are "black" programs with the
>> >same difficulty.
>
>> Nope. They use a mirror roughly the size of Hubble's.
>
>The ones we know about used mirrors that size. Anyone who actually
>knows the current situation -- I don't -- wouldn't be allowed to say.
>
Of course they're allowed to say. You can see the bloody things from
Earth, after all. Past a certain point a bigger mirror doesn't help
you for Earth observation. Atmosphere speckle becomes the driving
parameter and a bigger mirror doesn't help that.
>
>>
>> Remember, they're looking at something relatively close as such
>> things go.
>>
>
>6.5-m mirrors would have advantages over smaller ones.
>
No, they wouldn't. The next generation of recce satellites will use a
mirror right around 2.4 meters; the same size used since KH-11.
>
>(I don't see
>what distance has to do with anything.) I've seen hints that some
>have been built and deployed, but that may be salemanship. Companies
>vying for the JWST contract would have had an incentive to drop such
>hints whether true or not.
>
Don't let them kid you. Distance has a lot to do with everything when
it comes to telescopes.
>> The point is that a balloon does NOT replace a 'first stage'.
>
>We agree on that.
--
"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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| From | willner@cfa.harvard.edu (Steve Willner) |
|---|---|
| Date | 2018-06-25 21:17 +0000 |
| Message-ID | <pgrm4i$ifl$1@dont-email.me> |
| In reply to | #691157 |
In article <2frgidh5cfamkc9f50i79cts222ho7t09j@4ax.com>,
Fred J. McCall <fjmccall@gmail.com> writes:
> Oversize fairings are easy.
No doubt the JWST engineers wish you had told them that.
>>[mirror size of reconnaissance satellites]
> You can see the bloody things from Earth, after all.
See some of them, sure. Why do you think the census is complete?
What observations (equipment) are needed to measure their sizes?
> Past a certain point a bigger mirror doesn't help
> you for Earth observation. Atmosphere speckle becomes the driving
> parameter and a bigger mirror doesn't help that.
Are you assuming LEO and visible wavelengths? I don't see why either
one necessarily represents all reconnaissance satellites. And even
with those assumptions, what about temporal resolution? Taking short
exposures most certainly helps mitigate seeing effects.
("Atmospheric speckle" is only one of those effects.)
> No, they wouldn't. The next generation of recce satellites will use a
> mirror right around 2.4 meters; the same size used since KH-11.
Source? All of them or only some? Other than better sensors and
onboard processing, how do newer telescopes differ from the older
generation? (As you no doubt know but some readers may not, two of
those were declared surplus and delivered to NASA.)
> Distance has a lot to do with everything when
> it comes to telescopes.
What did you have in mind? I'd have said the key parameters are
angular resolution, temporal resolution, and sensitivity. Distance
affects requirements on those parameters, but I don't see that
distance _per se_ matters.
--
Help keep our newsgroup healthy; please don't feed the trolls.
Steve Willner Phone 617-495-7123 swillner@cfa.harvard.edu
Cambridge, MA 02138 USA
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| From | Fred J. McCall <fjmccall@gmail.com> |
|---|---|
| Date | 2018-06-25 15:52 -0700 |
| Message-ID | <err2jdtgfa6qocdehli253go6kmerapq9k@4ax.com> |
| In reply to | #691848 |
willner@cfa.harvard.edu (Steve Willner) wrote on Mon, 25 Jun 2018
21:17:06 -0000 (UTC):
>In article <2frgidh5cfamkc9f50i79cts222ho7t09j@4ax.com>,
> Fred J. McCall <fjmccall@gmail.com> writes:
>> Oversize fairings are easy.
>
>No doubt the JWST engineers wish you had told them that.
>
Well, someone should have if mirror size alone was the reason for
making it folding.
>>>[mirror size of reconnaissance satellites]
>
>> You can see the bloody things from Earth, after all.
>
>See some of them, sure. Why do you think the census is complete?
>What observations (equipment) are needed to measure their sizes?
>
What do you think they hide them behind? I think it's complete
because lots of people put lots of effort into it. And it takes a
telescope and some time to measure their size. This may be rocket
science, but it's EASY rocket science.
>> Past a certain point a bigger mirror doesn't help
>> you for Earth observation. Atmosphere speckle becomes the driving
>> parameter and a bigger mirror doesn't help that.
>
>Are you assuming LEO and visible wavelengths? I don't see why either
>one necessarily represents all reconnaissance satellites. And even
>with those assumptions, what about temporal resolution? Taking short
>exposures most certainly helps mitigate seeing effects.
>("Atmospheric speckle" is only one of those effects.)
>
You can only 'mitigate' so far. Are you one of those people who
believes the movies that you can make out faces from orbit and that
you can 'improve' an image with processing beyond the information that
it contains?
>> No, they wouldn't. The next generation of recce satellites will use a
>> mirror right around 2.4 meters; the same size used since KH-11.
>
>Source? All of them or only some? Other than better sensors and
>onboard processing, how do newer telescopes differ from the older
>generation? (As you no doubt know but some readers may not, two of
>those were declared surplus and delivered to NASA.)
>
Sources aren't hard to find. Here's one.
https://spaceflightnow.com/2015/05/01/next-round-of-u-s-optical-spy-satellites-to-start-launching-in-2018/
>> Distance has a lot to do with everything when
>> it comes to telescopes.
>
>What did you have in mind? I'd have said the key parameters are
>angular resolution, temporal resolution, and sensitivity. Distance
>affects requirements on those parameters, but I don't see that
>distance _per se_ matters.
>
'Temporal resolution' is difficult, given that both the satellite and
the Earth's surface are moving relatively rapidly with regard to each
other. Increased sensitivity means increased image noise. Distance
matters. That's why as newer satellites launch the older ones are
moved to lower orbits.
--
"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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| From | Jeff Findley <jfindley@cinci.nospam.rr.com> |
|---|---|
| Date | 2018-06-11 07:49 -0400 |
| Message-ID | <MPG.35882bbe599c0062989aca@news.eternal-september.org> |
| In reply to | #689966 |
In article <pfkpim$sa0$1@dont-email.me>, droleary@ 2017usenet1.subsume.com says... > For your reference, records indicate that > Jeff Findley <jfindley@cinci.nospam.rr.com> wrote: > > > High altitude balloon launch is a tad risky and only gains you a bit of > > altitude and zero velocity. Not worth the complexity and cost, IMHO. > > Like I said, it might not *currently* be viable, but as an alternative > technology it brings new sets of trade-offs to the table such that a few > tweaks here and there might make it viable for certain kinds of launches > (e.g., ?bulky? items that are hard to make aerodynamically efficient > benefit from starting at the highest possible altitude). Balloon launch isn't worth the trades which have to be made, IMHO. > > BFR/BFS is planned to be "zero waste" from the very beginning. Fully > > reusable TSTO with "gas and go" like operations. > > But that?s not the true ?zero waste? I was talking about. Any resources > that you?re sending up *and* down, along with any fuels you burn to do it > safely, is a waste. It may be a necessary waste for the current launch > technologies, so it?s good to minimize it, but I still say it?s a good > idea to think about ways to shoot stuff into space that doesn?t involve a > lot of heavy stuff coming back to Earth. By your definition, a passenger carrying aircraft is "waste" because it flies from one destination to another while carrying passengers. But that sort of "waste" is absolutely not a metric to optimize. Passengers are buying the cheapest ticket for the flight that gets them to their destination. They don't give a rat's ass about the "waste" of the actual aircraft having to fly there and back. Back to space launch. We're nowhere near the minimum cost per kg payload to orbit with chemical launch vehicles. Propellant costs are currently less than 1% of launch costs, even for SpaceX. Any "waste" of propellant that allows full reuse of hardware is currently worth the investment. When your hardware costs more than two orders of magnitude more than your propellant does, it makes a hell of a lot of sense to "expend" a bit of propellant to get your expensive hardware back intact. When faced with an optimization problem, you look for the biggest "bang for the buck" bits to optimize. Propellant "waste" is *not* that, not by a couple orders of magnitude. Also, your launch hardware is a precious commodity, so it makes all the sense in the world to recover it and use it multiple times, just like a passenger carrying jet aircraft. 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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| From | Thomas Koenig <tkoenig@netcologne.de> |
|---|---|
| Date | 2018-06-11 16:36 +0000 |
| Message-ID | <pfm8f1$ad9$1@newsreader5.netcologne.de> |
| In reply to | #689982 |
Jeff Findley <jfindley@cinci.nospam.rr.com> schrieb: > By your definition, a passenger carrying aircraft is "waste" because it > flies from one destination to another while carrying passengers. Of course. Firing passengers from large-caliber guns generates much less waste, obviously, and should be the preferred solution :-)
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| From | Sergio <invalid@invalid.com> |
|---|---|
| Date | 2018-06-11 14:02 -0500 |
| Message-ID | <pfmgvk$1b3d$1@gioia.aioe.org> |
| In reply to | #690015 |
On 6/11/2018 11:36 AM, Thomas Koenig wrote: > Jeff Findley <jfindley@cinci.nospam.rr.com> schrieb: > >> By your definition, a passenger carrying aircraft is "waste" because it >> flies from one destination to another while carrying passengers. > > Of course. > > Firing passengers from large-caliber guns generates much less waste, > obviously, and should be the preferred solution :-) > perhaps the passengers should walk.
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| From | benj <benj@nobody.net> |
|---|---|
| Date | 2018-06-11 17:23 -0400 |
| Message-ID | <ZKBTC.220840$o43.69663@fx33.iad> |
| In reply to | #690043 |
On 6/11/2018 3:02 PM, Sergio wrote: > On 6/11/2018 11:36 AM, Thomas Koenig wrote: >> Jeff Findley <jfindley@cinci.nospam.rr.com> schrieb: >> >>> By your definition, a passenger carrying aircraft is "waste" because it >>> flies from one destination to another while carrying passengers. >> >> Of course. >> >> Firing passengers from large-caliber guns generates much less waste, >> obviously, and should be the preferred solution :-) >> > > perhaps the passengers should walk. > Correct me if I'm wrong, Sergio, But then they would be "pedestrians" rather than passengers, right?
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| From | Sergio <invalid@invalid.com> |
|---|---|
| Date | 2018-06-11 21:20 -0500 |
| Message-ID | <pfnal2$ihi$1@gioia.aioe.org> |
| In reply to | #690089 |
On 6/11/2018 4:23 PM, benj wrote: > On 6/11/2018 3:02 PM, Sergio wrote: >> On 6/11/2018 11:36 AM, Thomas Koenig wrote: >>> Jeff Findley <jfindley@cinci.nospam.rr.com> schrieb: >>> >>>> By your definition, a passenger carrying aircraft is "waste" because it >>>> flies from one destination to another while carrying passengers. >>> >>> Of course. >>> >>> Firing passengers from large-caliber guns generates much less waste, >>> obviously, and should be the preferred solution :-) >>> >> >> perhaps the passengers should walk. >> > Correct me if I'm wrong, Sergio, But then they would be > "pedestrians" rather than passengers, right? you are right, again. Unless you consider them as "shoe" passengers, ugh. or if they were bundled together, like a tour group
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| From | Greg Goss <gossg@gossg.org> |
|---|---|
| Date | 2018-06-11 19:38 -0600 |
| Message-ID | <fo8mi9Fr0h9U1@mid.individual.net> |
| In reply to | #690015 |
Thomas Koenig <tkoenig@netcologne.de> wrote: >Jeff Findley <jfindley@cinci.nospam.rr.com> schrieb: > >> By your definition, a passenger carrying aircraft is "waste" because it >> flies from one destination to another while carrying passengers. > >Of course. > >Firing passengers from large-caliber guns generates much less waste, >obviously, and should be the preferred solution :-) Bobble tech doesn't bother with the guns. Just encapsulate then blow a nuke nearby. -- We are geeks. Resistance is voltage over current.
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| From | Doc O'Leary <droleary@2017usenet1.subsume.com> |
|---|---|
| Date | 2018-06-11 22:50 +0000 |
| Message-ID | <pfmubd$62p$1@dont-email.me> |
| In reply to | #689982 |
For your reference, records indicate that Jeff Findley <jfindley@cinci.nospam.rr.com> wrote: > Balloon launch isn't worth the trades which have to be made, IMHO. Certainly not today, no, or people would be doing it. But as I keep saying, new technologies keep popping up all the time that might make it viable in the future, at least for a few use cases. > By your definition, a passenger carrying aircraft is "waste" because it > flies from one destination to another while carrying passengers. Yes; that is true by any definition. Just because it’s (arguably) the least wasteful mode of transportation we currently have says nothing about how we might travel in the future. > They don't give a rat's ass about the "waste" of the > actual aircraft having to fly there and back. That same logic could have been used regarding ship or train travel prior to the airplane’s dominance. The point being that they *will* care as soon as a new technology comes along that allows more efficient travel. What that might be in reality is unknown, but clearly something like teleportation or Futurama-style tubes are sci-fi ways of moving just the bits that need to be moved from one location to another. > When your hardware costs more than two > orders of magnitude more than your propellant does, it makes a hell of a > lot of sense to "expend" a bit of propellant to get your expensive > hardware back intact. Yes. And I’m just wondering why you can’t just take the next step and admit that eliminating that expensive hardware *completely* would represent a cost saving of two orders of magnitude! You wrote it, but it’s like you weren’t really thinking about what your words actually meant. -- "Also . . . I can kill you with my brain." River Tam, Trash, Firefly
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| From | Fred J. McCall <fjmccall@gmail.com> |
|---|---|
| Date | 2018-06-11 21:03 -0700 |
| Message-ID | <a7huhd110t3tgdov1fm4vlv5mnhjkn26uq@4ax.com> |
| In reply to | #690124 |
Doc O'Leary <droleary@2017usenet1.subsume.com> wrote on Mon, 11 Jun
2018 22:50:22 -0000 (UTC):
>For your reference, records indicate that
>Jeff Findley <jfindley@cinci.nospam.rr.com> wrote:
>>
>> Balloon launch isn't worth the trades which have to be made, IMHO.
>>
>
>Certainly not today, no, or people would be doing it. But as I keep
>saying, new technologies keep popping up all the time that might make
>it viable in the future, at least for a few use cases.
>
Certainly not tomorrow or the next day, either. Just what are these
magical "new technologies" that keep "popping up all the time"?
>
>>
>> By your definition, a passenger carrying aircraft is "waste" because it
>> flies from one destination to another while carrying passengers.
>>
>
>Yes; that is true by any definition. Just because it’s (arguably) the
>least wasteful mode of transportation we currently have says nothing
>about how we might travel in the future.
>
If you want to talk about "how we might travel in the future", you
need to come up with some suggestions (that aren't PFM).
>
>>
>> They don't give a rat's ass about the "waste" of the
>> actual aircraft having to fly there and back.
>>
>
>That same logic could have been used regarding ship or train travel
>prior to the airplane’s dominance.
>
Nope. Ships and trains went 'there and back', too. Logic really
isn't your strong suit, is it?
>
>The point being that they *will*
>care as soon as a new technology comes along that allows more
>efficient travel. What that might be in reality is unknown, but
>clearly something like teleportation or Futurama-style tubes are
>sci-fi ways of moving just the bits that need to be moved from one
>location to another.
>
In other words, you're postulating some unspecified 'magic'. You're
posting into the wrong newsgroup. See the 'sci' at the front? That
means SCIENCE. That means you can't just wave your arms and fly to
the Moon. You have to actually put forward the scientific basis for
why you can do so.
>
>>
>> When your hardware costs more than two
>> orders of magnitude more than your propellant does, it makes a hell of a
>> lot of sense to "expend" a bit of propellant to get your expensive
>> hardware back intact.
>>
>
>Yes. And I’m just wondering why you can’t just take the next step and
>admit that eliminating that expensive hardware *completely* would
>represent a cost saving of two orders of magnitude! You wrote it, but
>it’s like you weren’t really thinking about what your words actually
>meant.
>
Because this is a SCIENCE newsgroup, you twat! Yes, magic would be
nice. We don't have it and never will. Get over it.
--
"Ordinarily he is insane. But he has lucid moments when he is
only stupid."
-- Heinrich Heine
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| From | Jeff Findley <jfindley@cinci.nospam.rr.com> |
|---|---|
| Date | 2018-06-12 06:44 -0400 |
| Message-ID | <MPG.35896e274b8718a3989acd@news.eternal-september.org> |
| In reply to | #690124 |
In article <pfmubd$62p$1@dont-email.me>, droleary@ 2017usenet1.subsume.com says... > > For your reference, records indicate that > Jeff Findley <jfindley@cinci.nospam.rr.com> wrote: > > > Balloon launch isn't worth the trades which have to be made, IMHO. > > Certainly not today, no, or people would be doing it. But as I keep > saying, new technologies keep popping up all the time that might make > it viable in the future, at least for a few use cases. I have an engineering degree. When developing new things, engineers work with what they have today because they've got schedules and deadlines to meet. You're talking about technologies not yet invented. That's research, not development. The two are not the same. > > By your definition, a passenger carrying aircraft is "waste" because it > > flies from one destination to another while carrying passengers. > > Yes; that is true by any definition. Just because it?s (arguably) the > least wasteful mode of transportation we currently have says nothing > about how we might travel in the future. Again, to an engineer the future is what you can do with existing tech. SpaceX has reduced launch costs beyond what any of the competition can deliver. They arguably didn't use any new technology at all. DC-X proved VTVL as a viable take of and landing mode. SpaceX applied that to Falcon 9's first stage. > > They don't give a rat's ass about the "waste" of the > > actual aircraft having to fly there and back. > > That same logic could have been used regarding ship or train travel > prior to the airplane?s dominance. The point being that they *will* > care as soon as a new technology comes along that allows more > efficient travel. What that might be in reality is unknown, but > clearly something like teleportation or Futurama-style tubes are > sci-fi ways of moving just the bits that need to be moved from one > location to another. Actually moving freight by rail is the cheapest way to move a ton of goods from point a to point b, assuming you can connect the two by rail. Aircraft have the advantage of speed, so your Amazon order gets there overnight instead of in a week or two, but you're paying for Amazon Prime, which isn't exactly cheap now is it? Two different sets of requirements lead to two completely different vehicles. That's how engineering optimization works. > > When your hardware costs more than two > > orders of magnitude more than your propellant does, it makes a hell of a > > lot of sense to "expend" a bit of propellant to get your expensive > > hardware back intact. > > Yes. And I?m just wondering why you can?t just take the next step and > admit that eliminating that expensive hardware *completely* would > represent a cost saving of two orders of magnitude! You wrote it, but > it?s like you weren?t really thinking about what your words actually > meant. As an engineer I quite simply can't do that. There is no *proven* existing tech that is cheaper than liquid fueled rocket engines for reaching orbit. What you are trying to get me to admit is that eventually, some day, there may be something better. Sure, there might. Also, monkeys might fly out of my butt. I'm not waiting for sci-fi to become reality. I'm working with what I've got today. Again, that's what engineers do. 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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| From | Sergio <invalid@invalid.com> |
|---|---|
| Date | 2018-06-12 09:57 -0500 |
| Message-ID | <pfon17$upc$2@gioia.aioe.org> |
| In reply to | #690183 |
On 6/12/2018 5:44 AM, Jeff Findley wrote: > In article <pfmubd$62p$1@dont-email.me>, droleary@ > 2017usenet1.subsume.com says... >> >> For your reference, records indicate that >> Jeff Findley <jfindley@cinci.nospam.rr.com> wrote: >> >>> Balloon launch isn't worth the trades which have to be made, IMHO. >> >> Certainly not today, no, or people would be doing it. But as I keep >> saying, new technologies keep popping up all the time that might make >> it viable in the future, at least for a few use cases. > > I have an engineering degree. When developing new things, engineers > work with what they have today because they've got schedules and > deadlines to meet. You're talking about technologies not yet invented. > That's research, not development. The two are not the same. > >>> By your definition, a passenger carrying aircraft is "waste" because it >>> flies from one destination to another while carrying passengers. >> >> Yes; that is true by any definition. Just because it?s (arguably) the >> least wasteful mode of transportation we currently have says nothing >> about how we might travel in the future. > > Again, to an engineer the future is what you can do with existing tech. > SpaceX has reduced launch costs beyond what any of the competition can > deliver. They arguably didn't use any new technology at all. DC-X > proved VTVL as a viable take of and landing mode. SpaceX applied that > to Falcon 9's first stage. > >>> They don't give a rat's ass about the "waste" of the >>> actual aircraft having to fly there and back. >> >> That same logic could have been used regarding ship or train travel >> prior to the airplane?s dominance. The point being that they *will* >> care as soon as a new technology comes along that allows more >> efficient travel. What that might be in reality is unknown, but >> clearly something like teleportation or Futurama-style tubes are >> sci-fi ways of moving just the bits that need to be moved from one >> location to another. > > Actually moving freight by rail is the cheapest way to move a ton of > goods from point a to point b, assuming you can connect the two by rail. > Aircraft have the advantage of speed, so your Amazon order gets there > overnight instead of in a week or two, but you're paying for Amazon > Prime, which isn't exactly cheap now is it? > > Two different sets of requirements lead to two completely different > vehicles. That's how engineering optimization works. > >>> When your hardware costs more than two >>> orders of magnitude more than your propellant does, it makes a hell of a >>> lot of sense to "expend" a bit of propellant to get your expensive >>> hardware back intact. >> >> Yes. And I?m just wondering why you can?t just take the next step and >> admit that eliminating that expensive hardware *completely* would >> represent a cost saving of two orders of magnitude! You wrote it, but >> it?s like you weren?t really thinking about what your words actually >> meant. > > As an engineer I quite simply can't do that. There is no *proven* > existing tech that is cheaper than liquid fueled rocket engines for > reaching orbit. > > What you are trying to get me to admit is that eventually, some day, > there may be something better. Sure, there might. Also, monkeys might > fly out of my butt. I'm not waiting for sci-fi to become reality. I'm > working with what I've got today. Again, that's what engineers do. > > Jeff > laws of physics do not change, and they constrain possable solutions, engineers make stuff real, and that stuff complies with physical laws.
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| From | benj <benj@nobody.net> |
|---|---|
| Date | 2018-06-12 17:52 -0400 |
| Message-ID | <hgXTC.307363$LR2.175833@fx41.iad> |
| In reply to | #690210 |
On 6/12/2018 10:57 AM, Sergio wrote: > On 6/12/2018 5:44 AM, Jeff Findley wrote: >> In article <pfmubd$62p$1@dont-email.me>, droleary@ >> 2017usenet1.subsume.com says... >>> >>> For your reference, records indicate that >>> Jeff Findley <jfindley@cinci.nospam.rr.com> wrote: >>> >>>> Balloon launch isn't worth the trades which have to be made, IMHO. >>> >>> Certainly not today, no, or people would be doing it. But as I keep >>> saying, new technologies keep popping up all the time that might make >>> it viable in the future, at least for a few use cases. >> >> I have an engineering degree. When developing new things, engineers >> work with what they have today because they've got schedules and >> deadlines to meet. You're talking about technologies not yet invented. >> That's research, not development. The two are not the same. >> >>>> By your definition, a passenger carrying aircraft is "waste" because it >>>> flies from one destination to another while carrying passengers. >>> >>> Yes; that is true by any definition. Just because it?s (arguably) the >>> least wasteful mode of transportation we currently have says nothing >>> about how we might travel in the future. >> >> Again, to an engineer the future is what you can do with existing tech. >> SpaceX has reduced launch costs beyond what any of the competition can >> deliver. They arguably didn't use any new technology at all. DC-X >> proved VTVL as a viable take of and landing mode. SpaceX applied that >> to Falcon 9's first stage. >> >>>> They don't give a rat's ass about the "waste" of the >>>> actual aircraft having to fly there and back. >>> >>> That same logic could have been used regarding ship or train travel >>> prior to the airplane?s dominance. The point being that they *will* >>> care as soon as a new technology comes along that allows more >>> efficient travel. What that might be in reality is unknown, but >>> clearly something like teleportation or Futurama-style tubes are >>> sci-fi ways of moving just the bits that need to be moved from one >>> location to another. >> >> Actually moving freight by rail is the cheapest way to move a ton of >> goods from point a to point b, assuming you can connect the two by rail. >> Aircraft have the advantage of speed, so your Amazon order gets there >> overnight instead of in a week or two, but you're paying for Amazon >> Prime, which isn't exactly cheap now is it? >> >> Two different sets of requirements lead to two completely different >> vehicles. That's how engineering optimization works. >> >>>> When your hardware costs more than two >>>> orders of magnitude more than your propellant does, it makes a hell of a >>>> lot of sense to "expend" a bit of propellant to get your expensive >>>> hardware back intact. >>> >>> Yes. And I?m just wondering why you can?t just take the next step and >>> admit that eliminating that expensive hardware *completely* would >>> represent a cost saving of two orders of magnitude! You wrote it, but >>> it?s like you weren?t really thinking about what your words actually >>> meant. >> >> As an engineer I quite simply can't do that. There is no *proven* >> existing tech that is cheaper than liquid fueled rocket engines for >> reaching orbit. >> >> What you are trying to get me to admit is that eventually, some day, >> there may be something better. Sure, there might. Also, monkeys might >> fly out of my butt. I'm not waiting for sci-fi to become reality. I'm >> working with what I've got today. Again, that's what engineers do. >> >> Jeff >> > > laws of physics do not change, and they constrain possable solutions, > engineers make stuff real, and that stuff complies with physical laws. > Actually the laws of physics DO CHANGE as they are only the understanding of humans and their current interpretation of what they perceive as reality. What you mean to say is that fundamental relationships governing physical phenomena do not change even if we don't quite know what they are. And what Jeff meant to say is that there is no "publicly known" technology cheaper than rockets for reaching orbit. Not quite the same thing as no "proven" technology. And as for "some day" such things can be important such as trying to find a workable alternative to fossil fuels which are certain to run out. The "green" idea of a return to the ox carts and the middle ages does not seem to be a way to lock in the the current advances of our civilization, does it?
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| From | Doc O'Leary <droleary@2017usenet1.subsume.com> |
|---|---|
| Date | 2018-06-12 15:20 +0000 |
| Message-ID | <pfoobm$hm7$1@dont-email.me> |
| In reply to | #690183 |
For your reference, records indicate that Jeff Findley <jfindley@cinci.nospam.rr.com> wrote: > I have an engineering degree. When developing new things, engineers > work with what they have today because they've got schedules and > deadlines to meet. You're talking about technologies not yet invented. > That's research, not development. The two are not the same. I never claimed they were. The topic of the thread is *not* “what can I build today”, it’s “Towards routine, reusable space launch.” That has nothing to do with today’s technology, and nobody has made the case that continued use of rockets (even reusable ones) can make it happen. > Two different sets of requirements lead to two completely different > vehicles. That's how engineering optimization works. Indeed. Which is why I argue that rockets alone are unlikely to be the only path to space. And they *definitely* are not the path to deep space. > What you are trying to get me to admit is that eventually, some day, > there may be something better. Sure, there might. Also, monkeys might > fly out of my butt. Really? You think new technologies are butt-monkeys unlikely? Then let’s get you retired, man, because you are *not* allowing your field to innovate nearly as much as it needs to. > I'm not waiting for sci-fi to become reality. I'm > working with what I've got today. Again, that's what engineers do. Then you should be looking in engineering newsgroups for that kind of discussion. Science is about more than just using your current tools. -- "Also . . . I can kill you with my brain." River Tam, Trash, Firefly
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