SpaceX Falcon Heavy Flight Animation

On Tuesday, February 3, 2015 at 11:24:55 PM UTC-5, Jeff Findley wrote:
In article ,
david.l.spain says...

On Tuesday, February 3, 2015 at 8:26:31 PM UTC-5, David Spain wrote:

The ocean-side of this equation is very interesting...

Dave

A side note on the issue:

http://www.professionalmariner.com/M...ing-challenge/

The Falcon 9 first stage uses 39,000 US gallons of kerosene. The above
article says that tugs can have diesel fuel tanks of "up to 100,000 or
more if intended for coastwise or offshore towing".

So, perhaps Musk isn't as crazy as everyone makes him out to be when you
take into account the costs of fuel and the other costs for the tugs and
barge. With a 100,000 tank, fueling an ocean going tug isn't at all
cheap.

Jeff

No it isn't. However... Take a look at what these things are towing when they are consuming in the 5/6 figures of gallons.

http://www.crowley.com/var/ezflow_si...ean-Towing.png

The ASDS hardly qualifies as a drilling platform. Now admittedly I'm drawing from my ag. background as a teen and the big CAT engines in these tugs are far far bigger than anything I used, BUT... 10,000 gallons of diesel is A LOT of fuel. I can't help shrug the feeling that towing the ASDS out to sea and back (forget the mass of the F9 booster, that's in the noise here) would take any more than that. In fact I'm thinking closer to 6000 gallons. Anybody from the marine towing business reading this? The ASDS masses and draws (according to Wikipedia):

Tonnage: 4,422 GT,[1] 1,326 NT,[1] 10,105 LT DWT[7]
Length: 288 ft (87.8 m)[1]
Beam: 100 ft (30.5 m)[1]
Depth: 19.8 ft (6.0 m)[1]

The F9 Stage 1 - 9R slightly heavier? (inert mass):
Type Falcon 9 v1.1 Stage 1
Length ~42m
Diameter 3.66m
Inert Mass ~18,000kg
Propellant Mass ~385,000kg - only a fraction of this on return

Figure calm seas. This thing isn't going to be landed in heavy seas.

Dave

http://www.spaceflight101.com/falcon-9-v11.html
http://en.wikipedia.org/wiki/Autonom...ort_drone_ship

On Wednesday, February 4, 2015 at 11:17:50 AM UTC-5, David Spain wrote:
The ASDS masses and draws (according to Wikipedia):

Tonnage: 4,422 GT,[1] 1,326 NT,[1] 10,105 LT DWT[7]
Length: 288 ft (87.8 m)[1]
Beam: 100 ft (30.5 m)[1]
Depth: 19.8 ft (6.0 m)[1]


Ah crap, Wikipedia is playing games again. They have double table entries for Length and Beam. One for the Marmac barge unmodified (above figures) and another set for it post modification to the ASDS which I list below (before some bright smart ass corrects me):

Length: 300 ft (91.4 m)[8]
Beam: 170 ft (51.8 m)[8]
Depth: 19.8 ft (6.0 m)[1]

They don't list different tonnage figures tho. Nothing like consistency. When it comes to Wikipedia, you get what you pay for!

http://en.wikipedia.org/wiki/Autonom...ort_drone_ship

Dave

In article ,
says...

On Tuesday, February 3, 2015 at 11:24:55 PM UTC-5, Jeff Findley wrote:

The Falcon 9 first stage uses 39,000 US gallons of kerosene. The above
article says that tugs can have diesel fuel tanks of "up to 100,000 or
more if intended for coastwise or offshore towing".

So, perhaps Musk isn't as crazy as everyone makes him out to be when you
take into account the costs of fuel and the other costs for the tugs and
barge. With a 100,000 tank, fueling an ocean going tug isn't at all
cheap.

No it isn't. However... Take a look at what these things are towing when they are consuming in the 5/6 figures of gallons.

http://www.crowley.com/var/ezflow_si...ean-Towing.png

The ASDS hardly qualifies as a drilling platform. Now admittedly I'm drawing from my ag. background as a teen and the big CAT engines in these tugs are far far bigger than anything I used, BUT... 10,000 gallons of diesel is A LOT of fuel. I can't help shrug the feeling that towing the ASDS out to sea and back (forget the mass of the F9 booster, that's in the noise here) would take any more than that. In fact I'm thinking closer to 6000 gallons. Anybody from the marine
towing business reading this? The ASDS masses and draws (according to Wikipedia):

Tonnage: 4,422 GT,[1] 1,326 NT,[1] 10,105 LT DWT[7]
Length: 288 ft (87.8 m)[1]
Beam: 100 ft (30.5 m)[1]
Depth: 19.8 ft (6.0 m)[1]

The F9 Stage 1 - 9R slightly heavier? (inert mass):
Type Falcon 9 v1.1 Stage 1
Length ~42m
Diameter 3.66m
Inert Mass ~18,000kg
Propellant Mass ~385,000kg - only a fraction of this on return

Figure calm seas. This thing isn't going to be landed in heavy seas.

Dave

http://www.spaceflight101.com/falcon-9-v11.html
http://en.wikipedia.org/wiki/Autonom...ort_drone_ship

I admit that I know nothing about fuel consumption of tugs
pushing/towing a barge like the ASDS out to the landing location and
back to the launch site. Whether or not to land at the launch site
versus on the ASDS depends on a lot of factors. But given the
construction of landing sites close to the launch site, I'm going to
have some faith that SpaceX has done the engineering and cost trades to
determine that landing on a concrete pad is preferable, even if it
results in some payload degradation.

That said, I've read SpaceX is building another ASDS for use at
Vandenberg. I've also read that they're upping the performance of the
Merlin 1D (presumably so Falcon 9 can handle larger payloads, such as
from DOD). This would also give more margins on lower payload launches,
increasing the amount of LOX/kerosene available for boost back and
landing.

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer

On Thursday, February 5, 2015 at 5:30:05 PM UTC-5, Jeff Findley wrote:
That said, I've read SpaceX is building another ASDS for use at
Vandenberg. I've also read that they're upping the performance of the
Merlin 1D (presumably so Falcon 9 can handle larger payloads, such as
from DOD). This would also give more margins on lower payload launches,
increasing the amount of LOX/kerosene available for boost back and
landing.

Jeff
--

That may be. And I shouldn't second guess SpaceX at their own business. But it still seems to be somewhat backwards to fuel for recovery with a bi-propellant of more expensive (than marine diesel) RP-1 and the additional LOX in place of mono-propellant diesel, IF it's cheaper in the end. And that really depends on how much is consumed by that tug. I mean if you don't have to fuel for RTLS then you can save that for what really counts the most for the customer and that is payload to orbit. Thus if you fuel less (or for less) you can *always* charge less. But then you have also to factor in the fixed overhead for a marine operation. If you can get rid of the ASDS tug and have it self propel under control of the command ship that would be an additional source of savings. It's fascinating to me, since, well since in aerospace, until now, we've never really had to deal with multi-modal recovery transport options that have to return a profit!

I'd LOVE to see the numbers, but of course I'm sure that's proprietary info!

I've seen scuttlebutt elsewhere that the 2nd (Pacific) ASDS will be used primarily for core booster recovery on the F9H-R, because it would not be feasible (or economical?) to attempt RTLS with the core booster. I would guess because, for at least for certain flight profiles, the downrange distance is too far to be economical or feasible to do a powered booster return.

Dave

On Wednesday, February 4, 2015 at 11:17:50 AM UTC-5, David Spain wrote:
On Tuesday, February 3, 2015 at 11:24:55 PM UTC-5, Jeff Findley wrote:
In article ,
david.l.spain says...

On Tuesday, February 3, 2015 at 8:26:31 PM UTC-5, David Spain wrote:

The ocean-side of this equation is very interesting...

Dave

A side note on the issue:

http://www.professionalmariner.com/M...ing-challenge/

The Falcon 9 first stage uses 39,000 US gallons of kerosene. The above
article says that tugs can have diesel fuel tanks of "up to 100,000 or
more if intended for coastwise or offshore towing".

So, perhaps Musk isn't as crazy as everyone makes him out to be when you
take into account the costs of fuel and the other costs for the tugs and
barge. With a 100,000 tank, fueling an ocean going tug isn't at all
cheap.

Jeff

No it isn't. However... Take a look at what these things are towing when they are consuming in the 5/6 figures of gallons.

http://www.crowley.com/var/ezflow_si...ean-Towing.png

The ASDS hardly qualifies as a drilling platform. Now admittedly I'm drawing from my ag. background as a teen and the big CAT engines in these tugs are far far bigger than anything I used, BUT... 10,000 gallons of diesel is A LOT of fuel. I can't help shrug the feeling that towing the ASDS out to sea and back (forget the mass of the F9 booster, that's in the noise here) would take any more than that. In fact I'm thinking closer to 6000 gallons.. Anybody from the marine towing business reading this? The ASDS masses and draws (according to Wikipedia):

Tonnage: 4,422 GT,[1] 1,326 NT,[1] 10,105 LT DWT[7]
Length: 288 ft (87.8 m)[1]
Beam: 100 ft (30.5 m)[1]
Depth: 19.8 ft (6.0 m)[1]

The F9 Stage 1 - 9R slightly heavier? (inert mass):
Type Falcon 9 v1.1 Stage 1
Length ~42m
Diameter 3.66m
Inert Mass ~18,000kg
Propellant Mass ~385,000kg - only a fraction of this on return

Figure calm seas. This thing isn't going to be landed in heavy seas.

Dave

http://www.spaceflight101.com/falcon-9-v11.html
http://en.wikipedia.org/wiki/Autonom...ort_drone_ship

Let's look at the facts:

Fuel Consumption of large ships:

https://people.hofstra.edu/geotrans/...inerships.html

Details about the recovery platform:

http://en.wikipedia.org/wiki/Autonom...ort_drone_ship

Marine fuel prices:

http://www.bunkerindex.com/prices/bi...riceindex_id=4

Alright...

The platform masses 10,000 tons and consumes about 150 tons per day of fuel when its underway at 21 knots. That's 6.25 tons per hour moving at 40 km/hr. That's 0.157 tons per km.

The ship operates 366 km away from the launch center at the point of recovery. So, the ship has to travel a 732 km round trip. 366 km out. 366 km back.

Thus, it will consume about 115 tons in transit. Add another 10 tons for station keeping and power generation, and you have 125 tons for recovery.

The cost of each ton of fuel is $603 - so that's a total cost of $75,375 per recovery.

Contrast this cost with the construction cost of a booster is in the $35 million. Or to the cost of rebuilding the booster and recertifying it for relaunch.

According to SpaceX President Gwynne Shotwell, it will cost $5 million to $7 million to recover and rebuild a booster certifying it for re-launch.

http://www.parabolicarc.com/2014/01/14/shotwell/

The cost of fuel to power the recovery platform and tow it around is 1% of this total.

http://images.forbes.com/special-rep...e-shotwell.jpg

So, this hand wringing over the exorbitant cost of moving empty boosters across the ocean is laughable in this context.

In article ,
says...

Jeff Findley wrote:
In article ,
http://www.professionalmariner.com/M...ing-challenge/

The Falcon 9 first stage uses 39,000 US gallons of kerosene. The
above article says that tugs can have diesel fuel tanks of "up to
100,000 or more if intended for coastwise or offshore towing".

So, perhaps Musk isn't as crazy as everyone makes him out to be when
you take into account the costs of fuel and the other costs for the
tugs and barge. With a 100,000 tank, fueling an ocean going tug
isn't at all cheap.

But how many trips is that tank going to get you? From David's link
it seems to say 3,000 to 5,000 gallons of fuel per day towing an ocean
barge (in 2008 and talking about more efficient engines being
deployed). How many days' sailing (round-trip I presume) are these
landing sites? And I think David has already suggested it would
probably be the lower end of the range if not below it given how
little mass beyond the barge itself there would be.

Agreed, I don't know for sure. On this next launch, it would be
interesting to track how many days the barge takes to get back to
Florida and multiply by two to get a very rough estimate for round trip
time in days. The last time, there were pictures posted on Reddit when
the barge arrived.

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer

Jeff Findley wrote:

In article ,
says...

But how many trips is that tank going to get you? From David's link
it seems to say 3,000 to 5,000 gallons of fuel per day towing an ocean
barge (in 2008 and talking about more efficient engines being
deployed). How many days' sailing (round-trip I presume) are these
landing sites? And I think David has already suggested it would
probably be the lower end of the range if not below it given how
little mass beyond the barge itself there would be.

Agreed, I don't know for sure. On this next launch, it would be
interesting to track how many days the barge takes to get back to
Florida and multiply by two to get a very rough estimate for round trip
time in days. The last time, there were pictures posted on Reddit when
the barge arrived.

Fuel consumption depends a lot on speed. There is no need to be in a
hurry moving the landing barge around.

--
Mvh./Regards, Niels Jørgen Kruse, Vanløse, Denmark

On Monday, February 9, 2015 at 5:55:24 AM UTC-5, Jeff Findley wrote:
In article , rick.jones2
says...

Jeff Findley wrote:
In article ,
http://www.professionalmariner.com/M...ing-challenge/

The Falcon 9 first stage uses 39,000 US gallons of kerosene. The
above article says that tugs can have diesel fuel tanks of "up to
100,000 or more if intended for coastwise or offshore towing".

So, perhaps Musk isn't as crazy as everyone makes him out to be when
you take into account the costs of fuel and the other costs for the
tugs and barge. With a 100,000 tank, fueling an ocean going tug
isn't at all cheap.

But how many trips is that tank going to get you? From David's link
it seems to say 3,000 to 5,000 gallons of fuel per day towing an ocean
barge (in 2008 and talking about more efficient engines being
deployed). How many days' sailing (round-trip I presume) are these
landing sites? And I think David has already suggested it would
probably be the lower end of the range if not below it given how
little mass beyond the barge itself there would be.

Agreed, I don't know for sure. On this next launch, it would be
interesting to track how many days the barge takes to get back to
Florida and multiply by two to get a very rough estimate for round trip
time in days. The last time, there were pictures posted on Reddit when
the barge arrived.

Jeff

And then there is the fuel the ASDS itself uses station-keeping in the ocean. In this case it will be a little higher than the norm if they are using the thrusters to station keep for the extra day. I'm assuming they are diesel electric. Or even if the tug has to intervene and tow in circles a bit, the ocean fuel consumption will be higher than "normal" for this flight.

So for launch delays, here's an argument - in favor - of RTLS.

But if the Shotwell quotes are correct, with refurbishment cost in the $3-5 million range, per launch, I guess fuel consumption is well in the noise here.
If launch rates were to increase tho, other logistics might come into play. I still think it is an interesting topic.

Dave

On Monday, February 9, 2015 at 10:36:33 AM UTC-5, David Spain wrote:
But if the Shotwell quotes are correct, with refurbishment cost in the $3-5 million range, per launch, I guess fuel consumption is well in the noise here.

Erm, I meant 7-9 million.

Dave

Rick Jones wrote:
Jeff Findley wrote:
So, perhaps Musk isn't as crazy as everyone makes him out to be
when you take into account the costs of fuel and the other costs
for the tugs and barge. With a 100,000 tank, fueling an ocean
going tug isn't at all cheap.

But how many trips is that tank going to get you? From David's link
it seems to say 3,000 to 5,000 gallons of fuel per day towing an
ocean barge (in 2008 and talking about more efficient engines being
deployed). How many days' sailing (round-trip I presume) are these
landing sites? And I think David has already suggested it would
probably be the lower end of the range if not below it given how
little mass beyond the barge itself there would be.

http://abcnews.go.com/Technology/wir...-test-28800420
suggests that for the DSCVR launch the barge was going to be 370
nautical miles away. I suspect that varies with the launch profile of
course.

rick jones
--
Process shall set you free from the need for rational thought.
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...