A Space & astronomy forum. SpaceBanter.com

Go Back   Home » SpaceBanter.com forum » Astronomy and Astrophysics » Astronomy Misc
Site Map Home Authors List Search Today's Posts Mark Forums Read Web Partners

Leaning tower of falcon 9



 
 
Thread Tools Display Modes
  #11  
Old June 20th 16, 06:56 PM posted to sci.space.policy,sci.physics,sci.astro
Fred J. McCall[_3_]
external usenet poster
 
Posts: 10,018
Default Leaning tower of falcon 9

JF Mezei wrote:

On 2016-06-19 11:45, Fred J. McCall wrote:

Non sequitur. Go back and read what I said.


Your assumptions are based on sending the barge to a failed landing and
refurbiushing it after the explosion being minimal costs.


I note that when called on a non sequitur response, your 'answer' is
to start snipping out context. Cost of sending the barge is DIESEL
FUEL. That's pretty much down in the noise. Have you LOOKED at one
of these barges? Just what do you think there is for an explosion to
damage? There are two cargo containers with 'support equipment'.
That's it.


My statement is that only accountants know this now. They have
experience in how much it costs to run the barge and support ship, and
they have had a few crashes to know what sort of damage is involved and
how many man hours/equipment this costs.


A lot of these numbers are public or easily inferred.


Elon Musk in an interveiw a while back even admitted that they don't yet
have all the numbers and enough data points to know whether refurbishing
will be good business.


The expectation is that they won't have to 'refurbish' anything. Just
inspect and refly.


Note that yesterday, he tweeted that he now expects 70% of landings to
be succesful. But IF those statistics were broken down to 95% of
ISS/LEO meissions being succesful and only 30% of GTO missions being
successful, you can see that this would affect whether they bother
trying to recover GTO missions to begin with.


Why?


I am not stating that they should or shouldn't bother. What I am saying
is that they need to have statistics on how each type of mission affects
recovery chances and run the numbers to see if this is a paying
proposition in the long term.

(and to get those numbers, they have to try as many landings as possible
which is what they are doing now.) Hopefully it does turn out that the
costs are low enough and success rate is high enough that they try to
recover all of them. But they don't have enough numbers yet, and since
the software is still evolving, the cutover between reliable landing and
unreliable landing is also moving to include more "reliable" landings.


Well, doh!


Falcon 9 isn't a 'paper bird'. It's flying hardware.


The landing part is still very much R&D. And the refurbishing of the
stage 1 is also R&D.


Non sequitur. But you cut all the context.

The idea is that you don't need to 'refurbish' the stages. You do a
quick inspection and then refly 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
  #12  
Old June 20th 16, 10:30 PM posted to sci.space.policy,sci.physics,sci.astro
Fred J. McCall[_3_]
external usenet poster
 
Posts: 10,018
Default Leaning tower of falcon 9

JF Mezei wrote:

On 2016-06-20 13:56, Fred J. McCall wrote:

A lot of these numbers are public or easily inferred.


So, SpaceX accounting is public ?


Read what I said, yammerhead.

OK, I'm going to type what follows REALLY SLOWLY. Read each sentence
and actually think about it until you understand what I've said.


The expectation is that they won't have to 'refurbish' anything. Just
inspect and refly.


NASA had the same expectation with the Shuttle too.


False. NASA had no such expectation for anything that even
approximated the vehicle that they actually built. The original
Shuttle concept was for a much smaller vehicle with much less
crossrange capability. That concept never got much beyond that stage.
THAT concept was the one NASA had the low refurbishment estimates for.
They NEVER had a 'zero refurbishment' expectation and they certainly
never had it for the vehicle they actually designed and built.
Claiming that they did is A LIE.

Learn something about the actual development history of the Space
Shuttle.


I don't believe Musk
as released any info on what's needed to get a landed Stage1 ready to
fly again. And I suspect they want a few more samples back before
drawing conclusions, so your conclusion that it is just "inspect and
refly" is premature.

It may end up as "inspect and refly". But until there is enough
experience, nobody can draw that conclusion.


With SpaceX we're talking about REAL HARDWARE. That hardware, unlike
the Space Shuttle, was designed around the idea that it could be
reflown around ten times with little to no refurbishment. SpaceX has
dismantled and inspected the first booster they recovered. They have
stated that it all looks clean and virtually brand new.

Learn something about what SpaceX is saying.



The idea is that you don't need to 'refurbish' the stages. You do a
quick inspection and then refly them.


At the moment, this is the dream. Whether that becomes reality depends
on the outcome of the tests being done with recent launches where a
stage was recovered.


No. At the moment, this is the intended design goal. All evidence to
date indicates that design goal is being met.

Again, learn something about what SpaceX is saying.


One issue is that they may find a stage to be fine and "inspect and
refly" is decided but at launch, something goes wrong and they realise
they forgot to inspect X for Y type of damage. That will come with
experience.


And fairies may **** magic dust all over things and make it all fail.

Again, learn something about what SpaceX is saying.


--
"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
  #13  
Old June 21st 16, 01:04 AM posted to sci.space.policy,sci.physics,sci.astro
Vaughn Simon
external usenet poster
 
Posts: 55
Default Leaning tower of falcon 9

On 6/20/2016 5:30 PM, Fred J. McCall wrote:
SpaceX has
dismantled and inspected the first booster they recovered. They have
stated that it all looks clean and virtually brand new.


Yet curiously SpaceX hasn't yet static test fired any recovered
boosters. I know that SpaceX is busy trying to increase their launch
tempo (and having considerable success) but this delay really is
starting to get curious, particularly in the face of their success at
recovery. Their stated goal was to static fire a recovered booster
several times, and to do it quickly. It hasn't happened. Why not?
  #14  
Old June 21st 16, 02:55 AM posted to sci.space.policy,sci.physics,sci.astro
Jeff Findley[_6_]
external usenet poster
 
Posts: 2,307
Default Leaning tower of falcon 9

In article . com,
says...

On 2016-06-20 17:30, Fred J. McCall wrote:

No. At the moment, this is the intended design goal. All evidence to
date indicates that design goal is being met.


Evidence based on 1 recovered stage 1. You are stating that the design
goal is being met based on that 1 point of data. I am stating it is too
early to state that it is being met.


SpaceX has recovered more than one stage. They've recovered four so
far. Here is an article with a picture showing all four (the one on the
right has been cleaned up a bit, but you can still see some of the soot
at the top end of the stage).

http://www.space.com/33102-spacex-le...-comes-ashore-
photos.html

You state that it can be reflow 10 times. I say that until they have
take a stage and reflown it multiple times, it is too early to say how
many times a stage can economically be reflown. ( refurb costs may
increase with number of flights for instance).


They've done extensive tests of the Merlin engines, which should be the
"long pole in the tent" when it comes to reflights without
refurbishment. I'm betting they'll meet that 10 flights without
refurbishment goal. Perhaps not right away, but given enough time.

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.
  #15  
Old June 21st 16, 02:59 AM posted to sci.space.policy,sci.physics,sci.astro
Jeff Findley[_6_]
external usenet poster
 
Posts: 2,307
Default Leaning tower of falcon 9

In article , says...

On 6/20/2016 5:30 PM, Fred J. McCall wrote:
SpaceX has
dismantled and inspected the first booster they recovered. They have
stated that it all looks clean and virtually brand new.


Yet curiously SpaceX hasn't yet static test fired any recovered
boosters.


Actually, they did in January:

SpaceX fire up returned Falcon 9 first stage at SLC-40
January 15, 2016 by Chris Bergin
https://www.nasaspaceflight.com/2016...alcon-9-first-
stage-slc-40/

I know that SpaceX is busy trying to increase their launch
tempo (and having considerable success) but this delay really is
starting to get curious, particularly in the face of their success at
recovery. Their stated goal was to static fire a recovered booster
several times, and to do it quickly. It hasn't happened. Why not?


I'm betting it's the huge backlog of launches to take care of. Paying
customers no doubt come first.

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.
  #16  
Old June 21st 16, 04:11 AM posted to sci.space.policy,sci.physics,sci.astro
Fred J. McCall[_3_]
external usenet poster
 
Posts: 10,018
Default Leaning tower of falcon 9

JF Mezei wrote:

On 2016-06-20 17:30, Fred J. McCall wrote:

No. At the moment, this is the intended design goal. All evidence to
date indicates that design goal is being met.


Evidence based on 1 recovered stage 1. You are stating that the design
goal is being met based on that 1 point of data. I am stating it is too
early to state that it is being met.

You state that it can be reflow 10 times. I say that until they have
take a stage and reflown it multiple times, it is too early to say how
many times a stage can economically be reflown. ( refurb costs may
increase with number of flights for instance).


And I'm stating that you are a fool and wasting my time.


--
"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
  #17  
Old June 21st 16, 04:12 AM posted to sci.space.policy,sci.physics,sci.astro
Fred J. McCall[_3_]
external usenet poster
 
Posts: 10,018
Default Leaning tower of falcon 9

Vaughn Simon wrote:

On 6/20/2016 5:30 PM, Fred J. McCall wrote:
SpaceX has
dismantled and inspected the first booster they recovered. They have
stated that it all looks clean and virtually brand new.


Yet curiously SpaceX hasn't yet static test fired any recovered
boosters. I know that SpaceX is busy trying to increase their launch
tempo (and having considerable success) but this delay really is
starting to get curious, particularly in the face of their success at
recovery. Their stated goal was to static fire a recovered booster
several times, and to do it quickly. It hasn't happened. Why not?


Because they're busy. Nothing 'curious' about that.


--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn
  #18  
Old June 21st 16, 11:09 AM posted to sci.space.policy,sci.physics,sci.astro
Jeff Findley[_6_]
external usenet poster
 
Posts: 2,307
Default Leaning tower of falcon 9

In article om,
says...

On 2016-06-20 21:55, Jeff Findley wrote:

SpaceX has recovered more than one stage. They've recovered four so
far.


If the first one that was recovered isn't the one which will fly first,
it means that it isn't really flyiable without refurb if another stage
is in a better condition.


Wrong. The first one is special, because it was first! It will
eventually go back to their headquarters in California to be permanently
displayed. Considering the amount of flown space vehicles in museums,
this is not at all surprising.

I have no problem with SpaceX taking its time to examine things. But the
fact that no a single stage has been designated for a reflight yet means
nobody should be making claims that "it'd a proven technology, it will
be able to fly 10 times without refurb" etc etc.


It should. There is nothing fundamental about a liquid fueled rocket
stage from an orbital launch vehicle that prevents reuse. It's just
that no one has *tried* all that hard to reuse one, until now.

Advocates of reusable launch vehicle tech have known this since the days
of the X-15 (earlier if you want to count the German rocket powered
fighter experience). It was rocket powered and the three copies which
were built flew so many times, I can never remember exactly how many
flights were made. Between then and now, engines have been repeatedly
fired on the test stand to test and qualify them. There is no
fundamental problem here that needs solving.

Just because there is higher degree of confindece that what SpaceX does
will happen (as opposed to NASA) doesn't mean that it is a done deal at
this point in time.


You're allowed to be a bit skeptical, but at the same time, there really
isn't much reason for it. A SpaceX first stage has to perform several
burns just to complete it's primary mission, then kill horizontal
velocity, then reentry burn, then landing burn. That's already
demonstrating several rapid restarts in the time span of a few minutes!

Since this is all new stuff, SpaceX has to develop validation tests for
those inspections. I am sure it os far mroe involved than looking at the
stage with a flashlight and using some Palmolive and s sponge to clean
off some burn marks.


What "new stuff"? Visual inspections? Validation firings on a test
stand? What do you expect them to do between flights?

Consider the one that landed "leaning". If landing was hard enough to
cause a leg to crumple, they probably have to do more expensive tests to
ensure the rest of the stack is fine since the other legs transfered the
full force of landing.


Possibly, but I doubt it since that's what the crushable inner core is
supposed to do. It wasn't unexpected at all.

And I would suspect that for each flight, they would have high speed
video of launch and several phases to detect any anomalies. Say they saw
something strange on takeoff, but stack landed fine. They will still
want to investigate.


Certainly, but if there had been a significant problem during that main
burn, there would not have been enough fuel left for a landing in the
first place. The landing fuel would have been burnt to make up for any
performance shortfall during the main burn to put the second stage and
payload on the right trajectory. So a successful primary mission is a
very good indicator that nothing serious went wrong.

In fact, the crumpled leg one is likely a good candidate to help develop
inspection/testing procedures since the likelyhood of something being
broken is higher on that one.


Again, possibly. But, pressurized tanks, which make up most of the
structure of the stage, are really freaking strong. As long as they
don't rupture, the stage as a whole is very likely o.k. I'm sure SpaceX
has done analysis and possibly even ground testing for this case and
already know what to expect. No, analysis and ground testing aren't a
replacement for flight testing, but this assumption that a stage might
be bad just because it's been to space and back is ludicrous.

Go re-read the history of the X-15. It was *always* expected it could
be reflown, barring a very hard landing because that was the case with
every aircraft before it! And even in the case of a hard landing, it
could be torn down and repaired. In all the flights of the X-15, only
one was permanently lost because it broke up and was destroyed during
flight.

Somehow, the launch vehicle guys in both the US and U.S.S.R. got a free
pass to ignore all of that experience with rocket engines and flight
vehicles and clung to the mistaken belief that launch vehicles must be
expendable simply because they started their engineering work with
missiles instead of aircraft. Madness. Simply madness.

It's mind boggling to think that it's taken the better part of a century
to start to meaningfully reverse that wrong headed thinking that never
should have existed in the first place.

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.
  #19  
Old June 21st 16, 11:21 AM posted to sci.space.policy,sci.physics,sci.astro
Jeff Findley[_6_]
external usenet poster
 
Posts: 2,307
Default Leaning tower of falcon 9

In article . com,
says...

On 2016-06-20 21:59, Jeff Findley wrote:

I'm betting it's the huge backlog of launches to take care of. Paying
customers no doubt come first.



Would it be correct to state that production of new stage1s has been
"productized" and is now running smoothly ? If they need to increase
production rate, then it is a matter of duplicating machines and
employees. Easier said than done, but folks like Boeing, Airbus increase
production rates routinely.


Sure, but that sort of capital investment costs a lot of money. Better
to reuse vehicles you've got than build new ones needlessly.

Would it be correct to state that recovery, inspection and attempts at
relaunch of used stage1s would be an R&D effort that would operate
separately from the production line ?


Most likely, but they would both share engineering, ground test, and
launch resources. SpaceX isn't building an entire spaceport in Texas
just for fun.

If so, it would not be impacted by attempts at increasing production of
new parts for stage1.


Nope. Building new stages is just one part of the overall process. The
rest is shared between new and flown stages.

However, budgets may be such that the R?D for reflight is limited
because not so strategically important/urgent. or maybe they reaslize it
is more work tnan they had thought.


It's limited by their orbital flight rate, since at this point in time
the test program is to recover and refly stages from actual orbital
missions. SpaceX has gone well beyond the realm of analysis and ground
test to the point that needlessly performing additional ground tests (on
unflown stages) just adds costs and generates little to no useful data.

Wher I can see some impact with production is in inspecting the landed
stages, they discover some part that is damaged and then tell production
folks to strenghten that part. (and then wait for that stage with
improve part to land so they can inspect it and perhaps use that one for
first reflight).

There are too many possibilities to draw any conclusions on this.


Yes, they'll find problems and fix them. That's a given. But to
timidly assume that vehicles are bad just because they've flown to space
and back is silly, especially since they've been designed from the
beginning to do just that.

Somehow we've lost our "guts". There are streets at Edwards Air Force
Base named after men who weren't afraid to climb into a flown vehicle
(many powered by rocket engines) and fly it again. Their names on the
streets were proof that this wasn't always successful. But, it is also
proof that they believed so strongly in advancing the state of the art
of aviation technology that they literally put their own lives on the
line in order to do it.

Why in the hell have we become so risk averse and timid? At times this
disgusts me, since it greatly limits progress.

Rand Simberg wrote a book about this very issue:

Safe Is Not an Option Paperback ? October 31, 2013
by Rand E. Simberg (Author), William Simon (Editor), Ed Lu (Foreword)
https://www.amazon.com/Safe-Not-Opti.../dp/0989135519

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.
  #20  
Old June 21st 16, 12:42 PM posted to sci.space.policy,sci.physics,sci.astro
Vaughn Simon
external usenet poster
 
Posts: 55
Default Leaning tower of falcon 9

On 6/20/2016 9:59 PM, Jeff Findley wrote:
Yet curiously SpaceX hasn't yet static test fired any recovered
boosters.

Actually, they did in January:

SpaceX fire up returned Falcon 9 first stage at SLC-40
January 15, 2016 by Chris Bergin
https://www.nasaspaceflight.com/2016...alcon-9-first-
stage-slc-40/

Thank you, I remember that now! But that is still far different from
the test they proposed, which I believe was supposed to be ten firings
to demonstrate the robustness of the booster. The article only mentions
one 2-second burn, and a questionable engine.

Incidentally it was also supposed to be done at their new pad, but with
the new "bleeding edge" super cooling equipment and procedures, I can
see where that may have slipped.
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
No escape tower on Dragon / Falcon 9 [email protected] Policy 0 October 1st 08 04:36 AM
No escape tower on Dragon / Falcon 9 Dr J R Stockton[_14_] Policy 0 September 30th 08 08:23 PM


All times are GMT +1. The time now is 01:46 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 SpaceBanter.com.
The comments are property of their posters.