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Towards routine, reusable space launch.



 
 
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  #1  
Old June 9th 18, 04:47 AM posted to rec.arts.sf.science,sci.physics,sci.astro,sci.space.policy
Fred J. McCall[_3_]
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Posts: 10,018
Default Towards routine, reusable space launch.

Doc O'Leary wrote on Fri, 8 Jun
2018 13:10:48 -0000 (UTC):

For your reference, records indicate that
"Robert Clark" wrote:

Several companies are proposing satellite megaconstellations that would
require hundreds to thousands of communications satellites. This may finally
provide the impetus to produce reusable launchers.


What are the actual numbers when it comes to savings from a reusable
rocket?


That depends on a lot of things.


It’d also be interesting to know how new technologies might
impact the economics of launching items into space (including just making
disposable launch vehicles much cheaper).


Real reuse will always be cheaper. If you can make disposable launch
vehicles much cheaper, the same technologies allow making reusable
launch vehicles much cheaper.


Once you start to contemplate
the need for multiple daily launches, even recovering boosters to reuse
them seems like a slow and labor-intensive process.


But orders of magnitude faster than throwing them away and building a
new one.


On the path to a
space elevator, it seems like there should be many more ways to reach
escape velocity that do a better job than what Musk is doing today.


You've discovered a good supply of unobtainium, have you? Otherwise,
rockets are your man for getting stuff to orbit for the foreseeable
future.


--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn
  #2  
Old June 9th 18, 06:19 PM posted to sci.space.policy,sci.astro,sci.physics,rec.arts.sf.science
Doc O'Leary[_3_]
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Posts: 13
Default Towards routine, reusable space launch.

For your reference, records indicate that
Fred J. McCall wrote:

Doc O'Leary wrote on Fri, 8 Jun
2018 13:10:48 -0000 (UTC):

What are the actual numbers when it comes to savings from a reusable
rocket?


That depends on a lot of things.


Well, sure, but it always helps to have some data to work with before
beginning an optimization process. Best/worst cases or averages or
whatever. What the savings is related to the total cost of the launch
is going to be guiding factor on how much effort it makes sense to
expend to re-use different parts of the system.

ItÂ’d also be interesting to know how new technologies might
impact the economics of launching items into space (including just making
disposable launch vehicles much cheaper).


Real reuse will always be cheaper. If you can make disposable launch
vehicles much cheaper, the same technologies allow making reusable
launch vehicles much cheaper.


That is non-obvious. Ideally, I would think a “zero waste” system
would be cheapest; every kg of mass that gets sent up either stays up
(doing something useful) or was the fuel. All this booster landing
(and subsequent refurbishing for relaunch) we’re seeing, while cool,
is definitely *not* the most efficient use of resources.

Once you start to contemplate
the need for multiple daily launches, even recovering boosters to reuse
them seems like a slow and labor-intensive process.


But orders of magnitude faster than throwing them away and building a
new one.


But that’s still assuming old technologies rather than new ones. You
don’t “throw away” a space elevator. Nor a mag-lev cannon. I’m not
sure how viable a high-altitude balloon launch would be, but it may
also be cheaper than traditional first-stage rockets.

On the path to a
space elevator, it seems like there should be many more ways to reach
escape velocity that do a better job than what Musk is doing today.


You've discovered a good supply of unobtainium, have you? Otherwise,
rockets are your man for getting stuff to orbit for the foreseeable
future.


It’s always a good idea to noodle around with other technologies, no
matter how impossible they appear to be today. Because, yes, rockets
are the way to get to orbit, but I’m most interested in the
*unforeseeable* future that has humans on other planets around other
stars. Just being satisfied with rockets is not going to make that
happen.

--
"Also . . . I can kill you with my brain."
River Tam, Trash, Firefly


  #3  
Old June 9th 18, 09:02 PM posted to sci.space.policy,sci.astro,sci.physics,rec.arts.sf.science
Jeff Findley[_6_]
external usenet poster
 
Posts: 2,307
Default Towards routine, reusable space launch.

In article , droleary@
2017usenet1.subsume.com says...

For your reference, records indicate that
Fred J. McCall wrote:

Doc O'Leary wrote on Fri, 8 Jun
2018 13:10:48 -0000 (UTC):

What are the actual numbers when it comes to savings from a reusable
rocket?


That depends on a lot of things.


Well, sure, but it always helps to have some data to work with before
beginning an optimization process. Best/worst cases or averages or
whatever. What the savings is related to the total cost of the launch
is going to be guiding factor on how much effort it makes sense to
expend to re-use different parts of the system.

It?d also be interesting to know how new technologies might
impact the economics of launching items into space (including just making
disposable launch vehicles much cheaper).


Real reuse will always be cheaper. If you can make disposable launch
vehicles much cheaper, the same technologies allow making reusable
launch vehicles much cheaper.


That is non-obvious. Ideally, I would think a ?zero waste? system
would be cheapest; every kg of mass that gets sent up either stays up
(doing something useful) or was the fuel. All this booster landing
(and subsequent refurbishing for relaunch) we?re seeing, while cool,
is definitely *not* the most efficient use of resources.


Falcon 9 is the "first generation" reuse for SpaceX. For "zero waste",
you'll have to wait for their "second generation" which will be BFR/BFS.

Once you start to contemplate
the need for multiple daily launches, even recovering boosters to reuse
them seems like a slow and labor-intensive process.


But orders of magnitude faster than throwing them away and building a
new one.


But that?s still assuming old technologies rather than new ones. You
don?t ?throw away? a space elevator. Nor a mag-lev cannon. I?m not
sure how viable a high-altitude balloon launch would be, but it may
also be cheaper than traditional first-stage rockets.


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.

On the path to a
space elevator, it seems like there should be many more ways to reach
escape velocity that do a better job than what Musk is doing today.


You've discovered a good supply of unobtainium, have you? Otherwise,
rockets are your man for getting stuff to orbit for the foreseeable
future.


It?s always a good idea to noodle around with other technologies, no
matter how impossible they appear to be today. Because, yes, rockets
are the way to get to orbit, but I?m most interested in the
*unforeseeable* future that has humans on other planets around other
stars. Just being satisfied with rockets is not going to make that
happen.


Sure, but SpaceX has proven that you can reduce costs dramatically by
using existing technology and introducing reuse of as many components as
possible. They're getting close to catching fairings and they have some
ideas for second stage reuse too. That would be very close to "zero
waste" with Falcon, if they can get to that point.

BFR/BFS is planned to be "zero waste" from the very beginning. Fully
reusable TSTO with "gas and go" like operations.

Also don't count out Blue Origin. They're off to a slow start, but have
a very reliable funding source in Jeff Bezos ($1 billion a year).

Besides, how you going to get those space elevator bits into orbit?
That's right, conventional (hopefully reusable) launch vehicles.

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.
  #4  
Old June 11th 18, 04:16 AM posted to rec.arts.sf.science,sci.astro,sci.physics,sci.space.policy
Doc O'Leary[_3_]
external usenet poster
 
Posts: 13
Default Towards routine, reusable space launch.

For your reference, records indicate that
Jeff Findley 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).

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.

Also don't count out Blue Origin. They're off to a slow start, but have
a very reliable funding source in Jeff Bezos ($1 billion a year).


I’m not counting them out, but when the topic is cost/efficiency, the
basic question is still how much energy is being expended to get each
kg into orbit. So long as the idea is still to send a lot of
supporting (non-fuel) heavy stuff up only to have most of it come back
down, there are wastes that a new technology can come in and improve
upon.

Besides, how you going to get those space elevator bits into orbit?
That's right, conventional (hopefully reusable) launch vehicles.


Hope for bigger things. I fully believe that, for a society to be
advanced enough to make a space elevator project realistic, it’s value
would be more incremental than revolutionary. Rockets are the best we
have right now, but we’re stuffed if that’s the best we can do.

--
"Also . . . I can kill you with my brain."
River Tam, Trash, Firefly


  #5  
Old June 11th 18, 05:19 AM posted to rec.arts.sf.science,sci.physics,sci.space.policy
Sergio
external usenet poster
 
Posts: 37
Default Towards routine, reusable space launch.

On 6/10/2018 10:16 PM, Doc O'Leary wrote:
For your reference, records indicate that
Jeff Findley wrote:



Hope for bigger things. I fully believe that, for a society to be
advanced enough to make a space elevator project realistic, it’s value
would be more incremental than revolutionary.




A space elevator is not possible in reality. It is a running joke in
engineering land.

calculate the mechanical loads.

calculate the weight of copper cables, and the mechanical cables

calculate the weight of the tower, and estimate the sizes of tower
sections to support the weight at different levels

estimate the weight of the electric motor 150 HP

going to use a counterweight ?


just ballpark it, assume 0.1 m/sec and 2000 # weight of cargo, and
100,000 foot high.

  #6  
Old June 11th 18, 06:25 AM posted to rec.arts.sf.science,sci.astro,sci.physics,sci.space.policy
Thomas Koenig
external usenet poster
 
Posts: 47
Default Towards routine, reusable space launch.

Doc O'Leary schrieb:

I’m not counting them out, but when the topic is cost/efficiency, the
basic question is still how much energy is being expended to get each
kg into orbit.


At the moment, not at all. Ballpark calculation:

An older version of a Falcon 9 reportedly had 488 tons of total
fuel, 147 of it RP-1 (a modified kerosene). Liquid oxygen is
quite cheap, and if we give RP-1 a cost of 1 dollar per kg,
we probably are in the right ballpark. So, around 150 000 Dollar
per launch.

This is _very_ low compared to all the other costs. A launch
cost around 50 to 60 million dollars now, if I remember the
figures right.
  #7  
Old June 11th 18, 11:19 AM posted to sci.space.policy
Scott M. Kozel[_2_]
external usenet poster
 
Posts: 160
Default Towards routine, reusable space launch.

On Monday, June 11, 2018 at 12:19:47 AM UTC-4, Sergio wrote:
On 6/10/2018 10:16 PM, Doc O'Leary wrote:

Hope for bigger things. I fully believe that, for a society to be
advanced enough to make a space elevator project realistic, it’s value
would be more incremental than revolutionary.


A space elevator is not possible in reality. It is a running joke in
engineering land.

calculate the mechanical loads.

calculate the weight of copper cables, and the mechanical cables


It wouldn't use copper cables, it would use carbon nanotube technology,
something that currently doesn't exist. Whether it ever will is debated.
That is for Earth.

For the Moon, the tether could be constructed from currently available
materials.
  #8  
Old June 11th 18, 12:00 PM posted to rec.arts.sf.science,sci.astro,sci.physics,sci.space.policy
Fred J. McCall[_3_]
external usenet poster
 
Posts: 10,018
Default Towards routine, reusable space launch.

Doc O'Leary wrote on Mon, 11 Jun
2018 03:16:38 -0000 (UTC):

For your reference, records indicate that
Jeff Findley 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).


And just what such items do we send to space?



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.


Well, let us know if you think of one that doesn't require unobtainium
or payloads to take tens of thousands of gravities on launch.



Also don't count out Blue Origin. They're off to a slow start, but have
a very reliable funding source in Jeff Bezos ($1 billion a year).


I’m not counting them out, but when the topic is cost/efficiency, the
basic question is still how much energy is being expended to get each
kg into orbit. So long as the idea is still to send a lot of
supporting (non-fuel) heavy stuff up only to have most of it come back
down, there are wastes that a new technology can come in and improve
upon.


We're constrained by the real world. Magic materials are right out.



Besides, how you going to get those space elevator bits into orbit?
That's right, conventional (hopefully reusable) launch vehicles.


Hope for bigger things. I fully believe that, for a society to be
advanced enough to make a space elevator project realistic, it’s value
would be more incremental than revolutionary. Rockets are the best we
have right now, but we’re stuffed if that’s the best we can do.


Just why are we 'stuffed'? Be specific.


--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn
  #9  
Old June 11th 18, 12:49 PM posted to rec.arts.sf.science,sci.astro,sci.physics,sci.space.policy
Jeff Findley[_6_]
external usenet poster
 
Posts: 2,307
Default Towards routine, reusable space launch.

In article , droleary@
2017usenet1.subsume.com says...
For your reference, records indicate that
Jeff Findley 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.
  #10  
Old June 11th 18, 05:36 PM posted to rec.arts.sf.science,sci.astro,sci.physics,sci.space.policy
Thomas Koenig
external usenet poster
 
Posts: 47
Default Towards routine, reusable space launch.

Jeff Findley 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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