Author Topic: Skepticism about reusability  (Read 25843 times)

Offline Lee Jay

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Re: Skepticism about reusability
« Reply #20 on: 12/12/2015 05:30 PM »
We aren't going to expand beyond Earth on chemical rockets.  Period.
Bold statement. Why not? None of the foreseen future technologies is suitable for Earth launch to LEO. Fusion, etc, is for in-space travel, not for launching.

A fusion tug, for example, could basically reduce the in space fuel requirements 100x. So chemical rocket launches would just have to launch components, not fuel. On a large exploration scale, giving that fuel (for fusion) would not be important on the mass budget, asteroid mining could become feasible. And chemical rockets would be "enough" just to launch the initial components, further components would be built from mining materials.

Think about this for a second.

The cost to launch a single human to low Earth orbit is on the order of 10-100 times the amount of money a single average person will earn in an entire lifetime.

Now add in the cost to move that person from LEO to, say, the surface of Mars, make that surface habitable for that person, and sustain that habitability for a lifetime.

Now add the cost to build an entire supply infrastructure on Mars to supply everything from raw materials to finished goods to food and clean water.

Unless and until the cost to get a person from the surface of the Earth to the surface of Mars becomes similar to the current cost of getting a person from, say, Los Angeles to London, we aren't going to move enough people and supplies there to seed a sustainable civilization.

Offline Dante80

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Re: Skepticism about reusability
« Reply #21 on: 12/12/2015 05:41 PM »
It isn't just the cost of refurbishment.  It is the loss of capability.  Falcon 9 v1.1, for example, could not do useful GTO missions if first stage recovery was attempted.  Falcon Heavy will only lift 6.5 tonnes to GTO (GEO-1800 m/s) with full recovery while weighing perhaps 1,400 tonnes at lifoff - nearly 70% as much as STS.  Compare that with Atlas 521, which can lift about as much while weighing only 429 tonnes at liftoff.  Or Ariane 64, which will lift 11 tonnes to GEO-1500 m/s while weighing 800 tonnes.  Or Proton M, which can lift nearly as much to GEO-1500 m/s for half the liftoff mass despite launching from 46 degrees latitude.

 - Ed Kyle

This is speculation on my part.

Your argument about Falcon Heavy is invalid. The 6.4mT quote has to do with pricing, not capability.

To give you an example.

F9 FT

Pricing
$61.2M for up to 4,850 kg @ GTO

Capability
LEO = 13,150 kg
GTO = 4,850  kg

FH

Pricing
$90M for up to 6,400 kg @ GTO

Capability
LEO = 53,000 kg
GTO = 21,200  kg

This is taken from here (the page was re-vamped last month or so).
http://www.spacex.com/about/capabilities

Now. Here is my premise.

1. F9 FT was developed so that it can be re-usable while getting a large sat out to 1,800m/s GTO. SES-9 might prove the concept (SES-9 is more than 5,000kg I think).
2. F9 FT gives a max GTO performance of 4,850kg. The payment plan applies to that capability.
3. FH will definitely put more payload to GTO than F9.
4. FH takes advantage of the F9 FT changes.
5. If F9 FT is re-usable @up to 4,850kg/GTO, then FH will almost certainly do more than 6,400kg when also re-usable.

Thus, I think that FH will be capable of carrying more than 6,400kg to orbit in commercial missions to GTO. If I might wager a guess, SX could be developing something like Speltra/Sylda to take advantage of FH's throw weight. It would make sense, wouldn't it?
« Last Edit: 12/12/2015 05:47 PM by Dante80 »

Offline Pipcard

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Re: Skepticism about reusability
« Reply #22 on: 12/12/2015 06:03 PM »
Elon Musk said that the Falcon Heavy can lift 7 tonnes to GTO "with full reusability of the all three boost stages.” I think he means that all three cores return to the launch site (for faster turnaround).

Musk/SpaceX intends to reuse their launchers, that is their short-term goal. If it works, it would be better to launch heavy satellites to GTO individually instead of using a SYLDA/SPELTRA-like system on the Falcon Heavy, especially to satisfy "higher flight rates."
« Last Edit: 12/12/2015 06:10 PM by Pipcard »

Offline Dante80

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Re: Skepticism about reusability
« Reply #23 on: 12/12/2015 06:13 PM »
Elon Musk said that the Falcon Heavy can lift 7 tonnes to GTO "with full reusability of the all three boost stages.” I think he means that all three cores return to the launch site (for faster turnaround).

Musk/SpaceX intends to reuse their launchers, that is their short-term goal. If it works, it would be better to launch heavy satellites to GTO individually instead of using a SYLDA/SPELTRA-like system on the Falcon Heavy, especially to satisfy "higher flight rates."

Yes, I know the quote, its from 2014 and before we knew about the exact upgrade FT brought. In that article, Elon talked only about densification, and some minor weight shedding. In the end, FT got a bigger interstange, bigger second stage, and different tank lengths. As well as more engine power via unlocking the M1-D.

Quote
“Where I basically see this netting out is Falcon 9 will do satellites up to roughly 3.5 tonnes, with full reusability of the boost stage, and Falcon Heavy will do satellites up to 7 tonnes with full reusability of the all three boost stages,”

SES-9 is 5,330kg, a LOT more than 3.5tons. Will F9 FT try to land on the barge? If yes, things have changed....a lot. We can extrapolate from that to get something for FH too (if F9 can do 5.3tons with re-usability in mind, it would be absurd to say that FH would only be able to do one ton more).

As always though, this stays as speculation at this point. And you do have a point about SX possibly favoring full-reusability vs double payloads.

If F9 FT shows in the near future that it can do the biggest GEO sats, and land back....what would the FH niche be, if not double payload missions?
« Last Edit: 12/12/2015 06:28 PM by Dante80 »

Online guckyfan

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Re: Skepticism about reusability
« Reply #24 on: 12/12/2015 07:59 PM »
The biggest GEO-sats are more than 6t. So Falcon Heavy would still have its place. Not to mention DOD sats that go directly to GEO. That needs a lot more capability.

If Elon Musk decides to do dual manifest like Arianespace they could do two of the biggest birds with center core expended. But he was strictly against that.

Offline gospacex

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Re: Skepticism about reusability
« Reply #25 on: 12/12/2015 08:16 PM »
We aren't going to expand beyond Earth on chemical rockets.  Period.

Why not? Question mark.

2-3% of glow gets to LEO.  Way less beyond that.

Way too much material usage, way too expensive (factor of 10,000).

97% of launcher's mass is not making orbit, true.

95% of the mass which isn't making orbit is fuel. Yes, it is irrevocably spent, but it is less than 1% of launch cost.

IOW: The fact that chemical fuel is used is not the cause of current high launch costs. It is responsible for ~1% of these costs.

Offline gospacex

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Re: Skepticism about reusability
« Reply #26 on: 12/12/2015 08:17 PM »
We aren't going to expand beyond Earth on chemical rockets.  Period.
Bold statement. Why not? None of the foreseen future technologies is suitable for Earth launch to LEO. Fusion, etc, is for in-space travel, not for launching.

A fusion tug, for example, could basically reduce the in space fuel requirements 100x. So chemical rocket launches would just have to launch components, not fuel. On a large exploration scale, giving that fuel (for fusion) would not be important on the mass budget, asteroid mining could become feasible. And chemical rockets would be "enough" just to launch the initial components, further components would be built from mining materials.

Think about this for a second.

The cost to launch a single human to low Earth orbit is on the order of 10-100 times the amount of money a single average person will earn in an entire lifetime.

Cost of launch has nothing to do with cost of chemical fuel.

Offline gospacex

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Re: Skepticism about reusability
« Reply #27 on: 12/12/2015 08:21 PM »
Unless and until the cost to get a person from the surface of the Earth to the surface of Mars becomes similar to the current cost of getting a person from, say, Los Angeles to London, we aren't going to move enough people and supplies there to seed a sustainable civilization.

Do you live in an alternate Universe where North America wasn't colonized by Europeans? They did it when getting from London to (the location of today's) Los Angeles was quite challenging, expensive and time-consuming.

Online KelvinZero

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Re: Skepticism about reusability
« Reply #28 on: 12/12/2015 08:30 PM »
We aren't going to expand beyond Earth on chemical rockets.  Period.

I think this definitely needs a separate thread. It is perfectly designed to invoke indignant protests (including from the actual rocket scientists who frequent here) and is almost entirely disconnected from the OP.

Offline Lee Jay

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Re: Skepticism about reusability
« Reply #29 on: 12/12/2015 08:56 PM »
We aren't going to expand beyond Earth on chemical rockets.  Period.

I think this definitely needs a separate thread. It is perfectly designed to invoke indignant protests (including from the actual rocket scientists who frequent here) and is almost entirely disconnected from the OP.

Realize I was just answering the below:

Can we seriously accept that we will continue to throw away $60 - $100 M (or more) of precision machinery and electronics after every launch for all of the foreseeable future and yet expect that we will still expand beyond the earth?

Offline edkyle99

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Re: Skepticism about reusability
« Reply #30 on: 12/12/2015 08:59 PM »
Elon Musk said that the Falcon Heavy can lift 7 tonnes to GTO "with full reusability of the all three boost stages.” I think he means that all three cores return to the launch site (for faster turnaround).

Musk/SpaceX intends to reuse their launchers, that is their short-term goal. If it works, it would be better to launch heavy satellites to GTO individually instead of using a SYLDA/SPELTRA-like system on the Falcon Heavy, especially to satisfy "higher flight rates."

Yes, I know the quote, its from 2014 and before we knew about the exact upgrade FT brought. In that article, Elon talked only about densification, and some minor weight shedding. In the end, FT got a bigger interstange, bigger second stage, and different tank lengths. As well as more engine power via unlocking the M1-D.
I believe that Mr. Musk knew precisely what Falcon 9 v1.1 Full Thrust was being designed to do when he said that Heavy will lift 7 tonnes to GTO with all boost stages recovered.   He had to know, given the timing of the development.  7 tonnes meshes with SpaceX's 6.4 tonne listing, with some buffer.  In addition, I've spent far too much time trying to model what SpaceX has been and will be doing.  The answers I see match more or less with what Mr. Musk said, and with what SpaceX advertises.  Reuse takes a hammer to GTO performance, dropping the capability by a factor or three or more. 

Falcon 9 v1.1 could not do, and did not do, landing attempts on GTO missions.  It didn't even carry legs on those missions.  Full Thrust might be an attempt to do recoveries on some GTO missions, but I'm not sure it will be able to do it on the heavier GTO payloads.  My estimate is that Full Thrust in expendable mode would lift about the same to GTO as Falcon Heavy in recoverable mode.

 - Ed Kyle
« Last Edit: 12/12/2015 09:05 PM by edkyle99 »

Offline sublimemarsupial

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Re: Skepticism about reusability
« Reply #31 on: 12/12/2015 09:07 PM »
Elon Musk said that the Falcon Heavy can lift 7 tonnes to GTO "with full reusability of the all three boost stages.” I think he means that all three cores return to the launch site (for faster turnaround).

Musk/SpaceX intends to reuse their launchers, that is their short-term goal. If it works, it would be better to launch heavy satellites to GTO individually instead of using a SYLDA/SPELTRA-like system on the Falcon Heavy, especially to satisfy "higher flight rates."

Yes, I know the quote, its from 2014 and before we knew about the exact upgrade FT brought. In that article, Elon talked only about densification, and some minor weight shedding. In the end, FT got a bigger interstange, bigger second stage, and different tank lengths. As well as more engine power via unlocking the M1-D.
I believe that Mr. Musk knew precisely what Falcon 9 v1.1 Full Thrust was being designed to do when he said that Heavy will lift 7 tonnes to GTO with all boost stages recovered.   He had to know, given the timing of the development.  7 tonnes meshes with SpaceX's 6.4 tonne listing, with some buffer.  In addition, I've spent far too much time trying to model what SpaceX has been and will be doing.  The answers I see match more or less with what Mr. Musk said, and with what SpaceX advertises.  Reuse takes a hammer to GTO performance, dropping the capability by a factor or three or more. 

Falcon 9 v1.1 could not do, and did not do, landing attempts on GTO missions.  It didn't even carry legs on those missions.  Full Thrust might be an attempt to do recoveries on some GTO missions, but I'm not sure it will be able to do it on the heavier GTO payloads.  My estimate is that Full Thrust in expendable mode would lift about the same to GTO as Falcon Heavy in recoverable mode.

 - Ed Kyle

So you would be very surprised if they attempt a landing for the 5300 kg SES-9 satellite then?

Online QuantumG

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Re: Skepticism about reusability
« Reply #32 on: 12/12/2015 09:09 PM »
It's hard to imagine the Falcon 9 is going to lower launch prices to 100th of the current prices.. and mostly because they've already halved the launch prices. A reusable first stage is only 1/10th of the problem.
I hear those things are awfully loud. It glides as softly as a cloud. What's it called? Monowhale!

Offline WindyCity

Re: Skepticism about reusability
« Reply #33 on: 12/12/2015 09:47 PM »
We aren't going to expand beyond Earth on chemical rockets.  Period.

Given your conclusion, would you care to speculate about why Musk and SpaceX take a different view? If I understand you correctly, you're saying that basic physics dictates that lifting sufficient mass to Mars in order to create a sustainable civilization is unfeasible. So what possibly lies behind Musk's counterclaim?

Offline Semmel

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Re: Skepticism about reusability
« Reply #34 on: 12/12/2015 09:48 PM »
As always, it comes down to cost. Lets get on topic then. From an other thread:

My estimates of F9 manufacturing costs are lower (assuming about non-reusable 15 F9 flights per year).

The major costs of a F9 flight are: R&D, capital costs (pads, etc.), corporate overhead (general admin, PA, etc.), sales and marketing, manufacturing and operations. Putting some numbers to those and assuming long term aim to break even (i.e. no profit)

___________________Total cost___Per flight cost___Notes
R&D$2 B$12 Massumes payback in 10 years at average of 17 flights per year
Capital$1 B$6 M4 pads, 4 landing pads, 4 integration buildings, 2 barges
Corporate overhead$5 MComplete guess
Sales and marketing$6 M10%
Operations$7 M
Manufacturing$25 M


I have no idea if that is true. But suppose it is.

On the first look, it seems like reusability can save up to 25M. R&D, Capital, Corporate overhead and Sales and marketing are fix cost per year, so can be reduced by increasing the number of flights. We know that the first stage is about 70% of the cost of the rocket, that is about 18M. Assuming no refurbishment costs of course. so lets assume, reusability does not increase number of launches, it can save at most 18M per launch. So as long as refurbishment is below 18M, its worth it. If the engines need to be replaced, its probably just borderline possible. If you can keep the engines and have to rebuild the rest, it might just borderline possible as well. But if neither happens, I would say SpaceX failed in their attempt of reusing rockets. The point is, we dont know before they try.

If reusibility works as advertised and have only about 1M of refurbishing and recovering cost. Suppose that this reduces the launch costs to 40M. This might make many satellite application possible that are just too expensive today. So assuming magic, SpaceX makes 150 launches per year and reuses each falcon 10 times. This will keep all costs roughly the same, except R&D, Capital, Corporate overhead and Sales and marketing have 1/10th of their price. That means we total at a cost of about 22M per launch. That assumes 7M operations, 2.5M 1st stage manufacturing, 1M recovery, 7.5M second stage, the rest are the annual company costs. This can only be reduced be having a reusable second stage, which is unlikely for F9. Making the operations cheaper would help. I have no idea what that takes though. Question is, as OP said, is the 1M recovering prize tag. But increasing the number of launches does help a lot as well. Even if refurbishing is much more costly than 1M, the factory to build the rockets does not need to grow linearly with the number of launches.
It is a big advantage to analyse the stages after they come back. I am very confident that adjustments to the F9 design will lead to a cost effective design. Shuttles were not flexible in their design. Once build, they were not redesigned and the lessons learned from reusability process cant bite. For F9, that is different. They are constantly replaced and improved.

Offline pippin

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Re: Skepticism about reusability
« Reply #35 on: 12/12/2015 10:20 PM »
Can we seriously accept that we will continue to throw away $60 - $100 M (or more) of precision machinery and electronics after every launch for all of the foreseeable future and yet expect that we will still expand beyond the earth?

No, but that's not what's happening today.
What's happening is that people are throwing away a much smaller value of precision machinery that also happens to have a huge amount of fixed cost overhead attributed to it which does not go away through reuse.

And ho much that is is something we don't know. SpaceX probably have some idea but it definitely depends on the flight rate.

We don't know whether of these $60-100mil it's actually $10-20mil that's really thrown away or it's $50-90mil but this is the crucial factor. Let's put it this way: if it were 50-90 mil I'm sure somebody else would have tried harder earlier on and if it was 10-20 mil I'm sure SpaceX would not bother either so it's likely somewhere in between.

And whatever it is, it then needs to be balanced against the added cost of refurbishing and inspection and the bigger rocket you need to compensate for the payload loss and how much _that_ is is what SpaceX tries to learn right now.

Offline Rocket Science

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Re: Skepticism about reusability
« Reply #36 on: 12/12/2015 10:26 PM »
This topic has been considered for the greater part of half a century with countless proposals the never got past the blueprint stage. We have a few players now that are seriously attempting full or partial reuse. I am just going to observe the various engineering experiments being tried and then draw conclusions from the results. I see it as a great time for rocketry!
« Last Edit: 12/12/2015 10:26 PM by Rocket Science »
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Offline CuddlyRocket

Re: Skepticism about reusability
« Reply #37 on: 12/12/2015 11:00 PM »
The best answer so far seems to be a simple "We don't really know"

And we'll never find out if someone doesn't give it a go!

I'm fairly confident that reusability can be made to work economically; though possibly not with the F9 and FH, which I see as experimental rockets designed to explore the regime whilst being good enough as expendable rockets to bring in sufficient income to pay for their development.

Online QuantumG

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Re: Skepticism about reusability
« Reply #38 on: 12/12/2015 11:03 PM »
The best answer so far seems to be a simple "We don't really know"

And we'll never find out if someone doesn't give it a go!

That's what they said about the Shuttle too. It's possible to learn the wrong lessons.
I hear those things are awfully loud. It glides as softly as a cloud. What's it called? Monowhale!

Offline francesco nicoli

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Re: Skepticism about reusability
« Reply #39 on: 12/12/2015 11:17 PM »
SpaceX is not the only player. Talking about reusability, what about Skylon?

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