SpaceX reusable booster experiments

In sci.space.policy Jeff Findley wrote:
I don't see why people keep getting hung up on how much fuel it's
going to take to fly back to the launch site. So what? Kerosene is
cheap and LOX is even cheaper since it is literally made from air!
If memory serves, fuel costs for Falcon 9 are 0.3% of the total
costs. Clearly, fuel costs aren't an issue.

Carbon footprint per kg to orbit?-)

rick jones
--
firebug n, the idiot who tosses a lit cigarette out his car window
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...

Jeff Findley wrote:

In article ,
says...

Before testing the F9 first stage's ability to return to the launch site,
perhaps it should be tested at solid surface landings but out at sea.

I don't see the benefit to this. Either the stage has enough delta-V to
get back to the launch site, or it doesn't. Landing on a floating,
bobbing, platform is harder than landing on a fixed surface. The only
way to fix this problem is more money (e.g. something like Sea Launch's
Odyssey platform).

I think that the point is to avoid destroying expensive launch
facilities if it doesn't work as designed. It's described above as an
interim goal.
--
We are geeks. Resistance is voltage over current.

In article , says...

Jeff Findley wrote:

In article ,
says...

Before testing the F9 first stage's ability to return to the launch site,
perhaps it should be tested at solid surface landings but out at sea.

I don't see the benefit to this. Either the stage has enough delta-V to
get back to the launch site, or it doesn't. Landing on a floating,
bobbing, platform is harder than landing on a fixed surface. The only
way to fix this problem is more money (e.g. something like Sea Launch's
Odyssey platform).

I think that the point is to avoid destroying expensive launch
facilities if it doesn't work as designed. It's described above as an
interim goal.

And destroying a large floating platform isn't expensive? Wikipedia
says that when it was originally built as an oil rig, Sea Launch's
Odyssey platform cost $110 million to build.

Either you have confidence that you can control the thing to a pinpoint
landing, or you don't. And if you do, it seems to make more sense to
target a flat expanse of concrete away from people and expensive ground
facilities than it does to target a multi-million dollar floating
platform in the ocean.

Aside from the vertical landing bit, this is very similar to a shuttle
landing. The shuttle landing facility (runway) wasn't built right next
door to the OPF or VAB because if the shuttle has a bad day on landing,
you don't want to take out anything else on the ground. Landing a F9
first stage would be similar.

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...

Jeff Findley wrote:

In article ,
says...

Before testing the F9 first stage's ability to return to the launch site,
perhaps it should be tested at solid surface landings but out at sea.

I don't see the benefit to this. Either the stage has enough delta-V to
get back to the launch site, or it doesn't. Landing on a floating,
bobbing, platform is harder than landing on a fixed surface. The only
way to fix this problem is more money (e.g. something like Sea Launch's
Odyssey platform).

I think that the point is to avoid destroying expensive launch
facilities if it doesn't work as designed. It's described above as an
interim goal.

And destroying a large floating platform isn't expensive? Wikipedia
says that when it was originally built as an oil rig, Sea Launch's
Odyssey platform cost $110 million to build.

Yeah. I was thinking more about his "small island" half of the
comment. The Odyssey platform becomes esentially the same (only more
expensive due to specialized location) as the expensive launch
facilities I was talking about protecting.
--
We are geeks. Resistance is voltage over current.

On 5/27/2014 2:23 PM, Robert Clark wrote:

It wasn't a fuel issue. It was a matter of safely testing the landing on
a solid surface prior to returning it to the actual launch pad. If the
off shore landing site is a converted oil platform such as the Sea
Launch Odyssey platform there will be minimal bobbing of the surface. If
it is an off shore island there will be none.

Bob Clark

An oil rig that is anchored to the sea floor doesn't have this problem
either. For a company like SpaceX, there are a plethora of existing oil
rigs in the Gulf of Mexico some of which are no doubt due for
decommissioning that could be had for a relative song (because the
federal government mandates decommissioned oil rigs must be disassembled
not abandoned in place) that offer perfect fly back options from a
launch point in Brownsville. Thereby offering a remote landing point
free from the NIMBY problem and w/o having to drop the booster into sea
water.

Such a converted oil rig could be used as a practice landing point until
confidence is achieved to enable the political "sell" of convincing the
FAA and a skeptical public that your "flying bomb", isn't. Thereby
allowing a return to launch site. Which I think we all agree is the best
cost option for a reusable booster.

Dave

In article , nospam@
127.0.0.1 says...

An oil rig that is anchored to the sea floor doesn't have this problem
either. For a company like SpaceX, there are a plethora of existing oil
rigs in the Gulf of Mexico some of which are no doubt due for
decommissioning that could be had for a relative song (because the
federal government mandates decommissioned oil rigs must be disassembled
not abandoned in place) that offer perfect fly back options from a
launch point in Brownsville. Thereby offering a remote landing point
free from the NIMBY problem and w/o having to drop the booster into sea
water.

Such a converted oil rig could be used as a practice landing point until
confidence is achieved to enable the political "sell" of convincing the
FAA and a skeptical public that your "flying bomb", isn't. Thereby
allowing a return to launch site. Which I think we all agree is the best
cost option for a reusable booster.

What "flying bomb"? A Falcon 9 first stage will be landing with almost
empty tanks.

Considering the approvals SpaceX has already gotten for Grasshopper,
Falcon 9 v1.1 reusable first stage testing, and Dragonfly (landing tests
of Dragon using Draco thrusters for landing), I really don't see FAA
approval being the problem you think it is.

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 Wednesday, May 28, 2014 10:28:17 AM UTC-4, Jeff Findley wrote:

What "flying bomb"? A Falcon 9 first stage will be landing with almost
empty tanks.


I'm reminded of the old line from a Monty Python episode. "...there is no cannibalism in the British Navy**".

Please don't confuse the messenger with the message. Based on engineering practice SpaceX has demonstrated to date, I have a good degree of confidence that if SpaceX believes they can safely bring a booster back to Brownsville, they can. But I'm not the one SpaceX has to convince.

Those that will be vehemently opposed will take the most extreme opposite position possible. If you are in this business you have to prepared for the worst case scenario. This is likely to be it.


Considering the approvals SpaceX has already gotten for Grasshopper,
Falcon 9 v1.1 reusable first stage testing, and Dragonfly (landing tests
of Dragon using Draco thrusters for landing), I really don't see FAA
approval being the problem you think it is.


Jeff


FAA approval is a political process too. So far SpaceX has seen little opposition because its activities have been confined to test ranges and infrequent operations. That plan, if all goes well, will change. So will the politics. I'm just playing the boy scout here. Saying be prepared. The oil rig scenario fits in well with the strategy SpaceX has been following so far. Build a little, test a little, fly a little.

Dave

http://www.ibras.dk/montypython/episode32.htm

**2nd Interviewer : The activity you see behind me is part of the preparations for the new Naval Expedition to Lake Pahoe. The man in charge of this expedition is Vice Admiral Sir John Cunningham. Sir John, hello there.

Sir John : Ah, hello. Well first of all I'd like to apologize for the behavior of certain of my colleagues you may have seen earlier, but they are from broken homes, circus families and so on and they are in no way representative of the new modern improved British Navy. They are a small vociferous minority; and may I take this opportunity of emphasizing that there is no cannibalism in the British Navy. Absolutely none, and when I say none, I mean there is a certain amount, more than we are prepared to admit, but all new ratings are warned that if they wake up in the morning and find any toothmarks at all anywhere on their bodies, they're to tell me immediately so that I can immediately take every measure to hush the whole thing up. And, finally, necrophilia is right out. (the interviewer keeps nodding but looks embarrassed) Now, this expedition is primarily to investigate reports of cannibalism and necrophilia in... this expedition is primarily to investigate reports of unusual marine life in the as yet uncharted Lake Pahoe.

In article ,
says...

On Wednesday, May 28, 2014 10:28:17 AM UTC-4, Jeff Findley wrote:

Considering the approvals SpaceX has already gotten for Grasshopper,
Falcon 9 v1.1 reusable first stage testing, and Dragonfly (landing tests
of Dragon using Draco thrusters for landing), I really don't see FAA
approval being the problem you think it is.

FAA approval is a political process too. So far SpaceX has seen little
opposition because its activities have been confined to test ranges
and infrequent operations. That plan, if all goes well, will change.
So will the politics. I'm just playing the boy scout here. Saying be
prepared. The oil rig scenario fits in well with the strategy SpaceX
has been following so far. Build a little, test a little, fly a
little.

True, politics will be involved. With the Russians stirring up trouble
and threatening to not sell the US anymore first stage engines for its
Atlas V launch vehicle (i.e. launches spysats), I don't think that
SpaceX will have too much trouble getting the FAA to approve the
attempted landing of an almost empty stage. They wouldn't want to
appear to be standing in the way of the progress of an American company
that is trying to get its launch vehicle certified to launch DOD
payloads in this political climate.

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

http://www.bloomberg.com/news/2011-0...hire-rate.html

There is a surplus of oil tankers.

http://en.wikipedia.org/wiki/Oil_tanker

550,000 DWT ships cost $120 million new. Used ones cost about $30 million used. Another $40 million in one of the Asian ship yards will get it outfitted however you like.

So, for less than $70 million, you have a 380 m long by 68 m wide ship, equipped with a Stewart Platform above the main deck,

http://en.wikipedia.org/wiki/File:He...neral_Anim.gif

with a mobile clamping system, that communicates with the descending stage capable of moving in two dimensions across the platform's surface. The ship itself is equipped with positioning jets for a dynamic positioning system to maintain absolute GPS coordinates

http://en.wikipedia.org/wiki/Dynamic_positioning

whilst the hexapod maintains absolute rock steady position for the landing platform, regardless of sea conditions.

Is $70 million plus $10,000 per hour too much to pay for such a platform?

A two stage launcher with a 2,200 km recovery down-range, with a 100 hour recovery time, and a 100 hour placement time, with a 50 hour on place time, 250 hours timex $10,000 per hour - $2.5 million per launch - added to the cost for recovery. That's 1.488 weeks per launch. With a launch every two weeks, that's 26 launches per year. With a 15 year life cycle, that's 390 launches. $70 million at 6.25% interest over 15 years is $109.88 million.. Dividing by 390 launches CAPEX costs $282,000 per launch. So, total cost of the platform is $2.8 million per launch to recover a booster that might cost $100 million per copy.

A TSTO RLV that lives 200 metric tons into LEO, with an 18% structure fraction, and a LOX/LH2 propellant combination, that has an exhaust velocity of 4.3 km/sec, and has a delta vee of 4.3 km/sec for the first stage and 4.9 km/sec for the second stage.

This means that we have a 7,605.4 tonne take off weight with an empty stage weight of 1,368.9 tonnes for the first stage, and 4,807.5 tonne propellant mass in the first stage. This stage is 88.9 m long and 15.9 m in diameter.. 29 pumpsets from the RS-68 are arrayed around the perimeter of a 15 m diameter aerospike engine. That's 191 tonnes of the stage weight. 180 tonnes of the stage weight is the airframe. The balance is recovery propellant, and other hardware used in the recovery effort.

The second stage masses 1,428.9 tonnes and masses 257.2 tonnes empty and carries a 200 metric ton payload into orbit using 971.7 tonnes of propellant. Five RS-68 pumpsets totalling 33.0 tonnes in weight, feed a smaller aerospike engine around the base of this stage. 10.6 m diameter by 59.0 m long stage forms the second stage, which sits atop the first stage. 53 tonnes is the airframe weight. The balance is recovery propellant and other hardware used in the recovery effort. The second stage, after orbiting the Earth, de-orbits, re-enters, and descends directly to the launch centre, returning often before the first stage has returned by action of the recovery ship.

At $23 million per tonne, and 1,368.9 + 257.2 = 1,626.1 each ship costs $37.4 billion. Development cost, plus supply chain along with three ships cost $187 billion. Over 15 years these three ships with this infrastructure will place 390 payloads of 200 tonnes each into orbit. A total of 78,000 tonnes. This will cost $19.57 billion per year to pay this CAPEX - assuming 6.25% and 15 year term. This is $752.68 million per launch. This is $3.76 million per tonne - or $3,760 per kg.