New Shuttle-derived booster squabbles

In article , bthorn64
@suddenlink.net says...

This is just ridiculous. Does anyone think NASA really wants SLS
anymore? I doubt it. I think this is Congress dictating engineering
decisions (albeit after years of NASA's famously bad decisions in this
field.) Five years ago, Shuttle-C/Jupiter/SLS would have made a lot of
sense... it could have been developed and fielded alongside the
Shuttle, making an easy transition. Today, that hope is long gone. The
Shuttle jobs are going, the few that remain. Get over it and move on.
This Congressionally-designed launch vehicle needs to be killed off.
And now. Let NASA buy Falcon Heavy and talk to ULA about Atlas Phase
Whatever, maybe even have a fly-off between them. That would still
cost a fraction of the $10 billion SLS is expected to cost (raise your
hand if you believe that estimate. Anyone? Hello?)

Enough already with their home-grown, hopelessly expensive Saturn V
Mk.II. Give NASA its marching orders: start planning to send humans
beyond LEO, but leave the Earth-to-LEO leg of the flight up to
industry. If we can trust industry with a $3 billion Mars rover, I
think we can trust them to loft a spacecraft with its own escape
system.

I'm in complete agreement. SLS just doesn't make sense anymore, if it
ever truly did.

The argument for it five years ago is that it would preserve some of the
shuttle workforce by preserving some of the shuttle's components in the
form of a new HLV. But NASA pi$$ed that all away by pursuing a much
bigger vehicle than was truly necessary (Ares V) and one that was
actually a bit too small (Ares I).

This debacle could have been avoided by building one vehicle using a
shuttle diameter tank, SRB's the same size as the shuttle (four
segments), and using existing engines (SSME's for the core and RL-10's
for the upper stage). The development of the upper stage could have
come later, as the vehicle would have been useful for LEO missions (like
testing Orion via trips to ISS). Yes, this would have been DIRECT, or
something very much like it.

Griffin "screwed the pooch" on this big time. :-(

Jeff
--
" Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry
Spencer 1/28/2011

Jeff Findley wrote:

Griffin "screwed the pooch" on this big time. :-(


I dunno Jeff, even Direct as a HLV would have been pricey compared to Falcon
Heavy. In retrospect, maybe Griff did us all a favor, not intentionally mind
you... :-)

Dave

Some "To LEO" comparisons:

According to Direct document below, Direct shows a "6.7 fold improvement"
($4815/kg vs $32,385/kg) cost effectiveness over "STS" (in 2009 I presume that
means Ares), so I didn't bother with Ares figures in this...

DIRECT

77.8 mT / launch = 77,800 kg / launch
@$1.29B/yr (2009 dollars assumed 5 launches / yr) or:

77,800 kg / launch
$258M / launch (at assumed launch rate in 2009 dollars)

pg: 31 from:
http://www.launchcomplexmodels.com/D..._ISDC_2009.pdf

FALCON HEAVY

53,800 kg / launch
$80-125M / launch (2013 dollars - no minimum)

http://www.spacex.com/falcon_heavy.php

David Spain wrote:
Some "To LEO" comparisons:

According to Direct document below, Direct shows a "6.7 fold
improvement" ($4815/kg vs $32,385/kg) cost effectiveness over "STS" (in
2009 I presume that means Ares), so I didn't bother with Ares figures in
this...

After review STS clearly refers to Shuttle NOT Ares. I should have looked more
closely at the pie chart on this page before posting.

Maybe they didn't want to step on too many NASA toes at the time. But the
absence of Ares data is noted (and noticeable).

Also I purposely left out any NRE so as not to keep the operating costs clear,
and separate from the development costs. I am assuming the quoted page from
the Direct presentation is also.

To be totally fair to the Direct approach, their approach and cost figures
derive from the goal being the original VSE (read Lunar missions) in mind not
LEO to ISS. Which is all SpaceX is on the hook to deliver (for now).

Still SpaceX is setting the bar very low... :-)

Dave

On 5/13/2011 8:39 AM, David Spain wrote:

FALCON HEAVY

53,800 kg / launch
$80-125M / launch (2013 dollars - no minimum)

http://www.spacex.com/falcon_heavy.php

If Musk can bring in Falcon Heavy with the promised performance and at
that cost, it's going to make all other heavy boosters look pathetic by
comparison.
Even the Chinese say he can undersell them:
http://satellite.tmcnet.com/topics/s...chers-cost.htm
How he's doing this is interesting.
National space programs were partially set up as public works programs
by the countries that did them, so they tried to hire a lot of people
and farm out the work between many aerospace firms to help support the
national aerospace industry.
Musk is running his operation like a business, not a public works
program; employees are kept to as few as possible, and anything that can
be built by SpaceX rather than a subcontractor is built by SpaceX,
removing the profit margin that would be realized by the subcontractors
otherwise and lowering the overall cost of the booster.

Pat

David Spain wrote:
Also I purposely left out any NRE so as not to keep the operating costs
^^^ delete!
clear, and separate from the development costs.

Egads!

In sci.space.history Pat Flannery wrote:
What's interesting about SpaceX is that everyone thought that a
reduction in launch costs would come from some new technology, and
Musk returned to the most basic of rocket technologies, like
clustered mass produced Lox/kerosene engines and no cryogenics in
the upper stage to get Falcon 9's costs down

I guess because it is the oxidizxer rathe than the fuel LOX doesn't
count as a cryogenic?

What is the freezing point of RP-1? http://en.wikipedia.org/wiki/RP-1
doesn't metion it, but http://en.wikipedia.org/wiki/Jet_fuel talks
about temps below -40. I suppose for short durations that is a don't
care in an upper stage?

rick jones
--
oxymoron n, commuter in a gas-guzzling luxury SUV with an American flag
these opinions are mine, all mine; HP might not want them anyway...
feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...

Pat Flannery writes:

What's interesting about SpaceX is that everyone thought that a
reduction in launch costs would come from some new technology, and Musk
returned to the most basic of rocket technologies, like clustered mass
produced Lox/kerosene engines and no cryogenics in the upper stage to
get Falcon 9's costs down

Lots of people not being pressure-fed with government dollars thought
that exactly this was the way to go... But then nobody asked them.


Jochem

--
"A designer knows he has arrived at perfection not when there is no
longer anything to add, but when there is no longer anything to take away."
- Antoine de Saint-Exupery

On 5/13/2011 11:32 AM, David Spain wrote:
To be totally fair to the Direct approach, their approach and cost
figures derive from the goal being the original VSE (read Lunar
missions) in mind not LEO to ISS. Which is all SpaceX is on the hook to
deliver (for now).

Still SpaceX is setting the bar very low... :-)

What's interesting about SpaceX is that everyone thought that a
reduction in launch costs would come from some new technology, and Musk
returned to the most basic of rocket technologies, like clustered mass
produced Lox/kerosene engines and no cryogenics in the upper stage to
get Falcon 9's costs down


Pat

LOX is a cryogen, but not one that's as difficult as cryogenic
hydrogen. Hydrogen isn't that difficult today either. Handling
hydrogen is the basis of its use as a terrestrial fuel. So, it need
not be expensive. In fact, the attraction I have toward liquid
hydrogen is that its also the basis of a hydrogen economy, so its a
technology driver in the energy field assuming low cost hydrogen
production with solar or nuclear sources.

Still lets compare LOX/H2 with LOX/RP1

Hydrogen/Oxygen combinations have 4.5 km/sec exhaust speeds with a 6:1
oxygen fuel ratio by weight. So,

GAS DENSITY MASS VOLUME
Lox 1.14 kg/liter 6 kg 5.26 liters
H2 0.07 kg/liter 1 kg 14.29 liters

0.36 kg/liter 7 kg 19.55 liters

The S-IVB attains an 11.6% structure fraction in 1960s. This was an
upper stage and needn't be built as heavily. So, today we might
attain for a lower stage, something in this range. Let's say 12%
structure in the first stage and a 10% structure in the upper stage.
Or 15% structure for a reusable stage.

RP-1/Oxygen combinations have 3.4 km/sec exhast speeds with a 2.56:1
oxygen fuel ratio by weight. So,

PROP DENSITY MASS VOLUME

Lox 1.14 kg/liter 2.56 kg 2.25 liters
RP1 0.81 kg/liter 1.00 kg 1.23 liters

1.02 kg/liter 3.56 kg 3.48 liters

The S1-C has a structure fraction of 12.8% - but it carried the entire
Saturn V through Max Q. The Falcon Heavy attains a 9% structure
fraction today - so we'll use that for the first stage 7% structure in
the upper stage, and 11% structure for a reusable system.


Let's look at putting up 10 tons with a two stage to orbit rocket with
various combinations. Our goal is to impart an idealized 9.2 km/sec
to the payload to attain a 330 km orbit from Cape Canaveral with two
stages imparting 4.6 km/sec each.

Propellant Fraction
Type H2 64.02% RP1 74.15%

Stage Structure Fraction & Payload Fraction
Low 10% 25.98% 7% 18.85%
High 12% 23.98% 9% 16.85%
Reusable 15% 20.98% 11% 14.85%

Orbiter Stage Structure and Total Weight
Low 3.85 38.49 3.71 53.06
High 5.00 41.70 5.34 59.35
Reusable 7.15 47.67 7.41 67.35

Booster Stage Structure and Total Weight
Low 10.97 148.16 15.99 281.50
High 15.86 173.91 26.36 352.30
Reusable 26.93 227.20 42.49 453.60

So, we can see that an a two-stage system to place 10 tonnes into LEO
from Cape Canaveral will have the following characteristics;


LOX/LH2 - Low - 148.16 TOW - 14.82 structure
LOX/LH2 - High- 173.91 TOW - 20.86 structure
LOX/LH2 - Reus-227.20 TOW - 24.12 structure

LOX/RP1 - Low - 281.50 TOW - 19.70 structure
LOX/RP1 - High-352.30 TOW - 31.70 structure
LOX/RP1 - Reus-453.60 TOW - 49.90 structure

The cost of LOX/LH2 is slightly higher in structure than LOX/RP1, is
the same in avionics and control, and higher in propulsion, and higher
in infrastructure. The cost of launch infrastructure scales with Take
off weight (TOW). On average we have the following ratio, looking at
the cost history of various systems like the Saturn V and Atlas;

COMPARISON OF COSTS

Vehicle
LOX/LH2 vs LOX/RP1: 1.0x avionics x mass - 15% total
LOX/LH2 vs LOX/RP1: 1.1x structure x mass - 35% total
LOX/LH2 vs LOX/RP1: 1.8x propulsion x TOW - 50% total

Launch Center
LOX/LH2 vs LOX/RP1: 1.5x infrastructure take off weight

RESULTS

Vehicle

LOX/LH2 Light 0.94
LOX/RP1 Light 1.00
LOX/LH2 Heavy 1.11
LOX/RP1 Heavy 1.27
LOX/LH2 Reuse 1.48 (0.296 x 5)
LOX/RP1 Reuse 1.67 (0.334 x 5)

Infrastructure (100 launches over life)

LOX/LH2 Light 0.79 (0.008 x 100)
LOX/LH2 Heavy 0.93 (0.009 x 100)
LOX/RP1 Light 1.00 (0.010 x 100)
LOX/LH2 Reuse 1.21 (0.012 x 100)
LOX/RP1 Heavy 1.25 (0.013 x 100)
LOX/RP1 Reuse 1.61 (0.016 x 10))

A reusable LOX/LH2 system that is used at least 5x is superior to any
expendable system, and higher specific impulse beats out lower cost
lower specific impulse every time due to the larger size of a low
specific impulse system for a given payload to orbit.

As the 1960s studies of Sea Dragon shows, very large systems have the
capacity to reduce costs by operation of economies of scale to change
these factors. Larger systems are preferred for any real industrial
use of outer space to resolve environmental and resource problems for
Earth's population today in any case.

On 5/13/2011 2:46 PM, Jochem Huhmann wrote:
Pat writes:

What's interesting about SpaceX is that everyone thought that a
reduction in launch costs would come from some new technology, and Musk
returned to the most basic of rocket technologies, like clustered mass
produced Lox/kerosene engines and no cryogenics in the upper stage to
get Falcon 9's costs down

Lots of people not being pressure-fed with government dollars thought
that exactly this was the way to go... But then nobody asked them.

It's somewhat like the way the British airline industry died. Rather
than a company like Boeing or Douglas going to the airlines and asking
them what they wanted, the British government would order to be built
what they thought the airlines needed, and then try to force it down
their throats.

Pat