Author Topic: SpaceX Falcon 9 : Iridium NEXT Flight 4 : December 22/23, 2017 : Discussion  (Read 81606 times)

Offline UKobserver

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I think we are being too absolute in our arguments;

If Elon/SpaceX have shown anything, it is that they are very pragmatic in their decision making. They are constantly weighing their wish to push on with their experimentation and evolution of their technologies against the need to do a good job for their customers and build up those relationships. Several times they have chosen to sacrifice recovery margins (making for a hotter and more damaging re-entry) or even the recovery itself in order to boost the customer into a better orbit than contractually agreed, particularly where those customers have been waiting a long time and potentially have lost income as a result.

In a similarly pragmatic way, for Iridium 4 they have traded their wish to get a first west coast RTLS under their belt for their equally strong wish to get an important, high-profile, customer to start using pre-flown boosters and get as much use as they can out of their already built and paid-for inventory.

Therefore when we hear that this mission is going to be flown expendable, and we simultaneously hear that the filed ASDS landing location shifted a long way south when they opted to switch to a re-used block 3 booster, our immediate thought out to be that they are making some sort of engineering/customer support trade here.

I think both of the two theories that have been postulated above in this vein could be true, which were;

1. That in return for re-using a pre-flown booster they have promised Matt Desch delivery to a slightly higher initial orbit, so as to reduce the time needed to raise the satellites into their final orbits, and;

2. That they may indeed have traded some or all of the recovery margin to test out something else which requires adding mass to the stage, such as a further evolution of the fairing recovery, as cscott postulated, and which is made more likely by the fairing recovery ship having been switched to the west coast. It could be that they have accepted a heavier recoverable fairing design for Block 5, but want to test it now, and can only do so on a less-powerful block 3 booster by sacrificing margin somewhere else, such as removing the weight of the landing legs and grid fins.

What I don't think we can yet conclude is that;

a) the marginal cost of recovery is greater that the scrap value of the materials in the booster. I suspect that recovery costs are actually pretty low, given how SpaceX never spends any more than they need to on their equipment. As an example compare the size and spec of their tugboats and the fairly rudimentary (simple but effective) design of their ASDS barges, compared to the gold-plated designs planned by Blue Origin. I would certainly guess that recovery is just a small fraction of the cost of actually building the booster, hence why it makes sense to recover it in the first place, but what the actual value of the materials contained within the rocket is would be hard to guess. It's not impossible that it might be less than the cost of recovery, but I don't think we can conclude that much solely from the fact that they are expending this booster. Not without further information.

b) they don't need or want to recover any more boosters. We're lacking some important information here as to how many times they wish or intend to use these older recovered boosters, and it might even be that SpaceX themselves haven't decided yet, and that it might depend on how successful their block 5 design proves to be, and how quickly they can reduce the refurbishment time of that booster. A few things to think about in that regard;

i) they have obviously felt it worthwhile to try to recover all of the boosters that have made a second flight so far. This might be just so that they could inspect them and learn more lessons about re-usability, but it might also mean that they would consider using these boosters a third time, perhaps for the initial launches of their own satellite constellation, to really reduce the capital outlay required for that.

ii) they haven't yet reflown a booster that has performed a GTO profile, but note that they have converted one of these into one of their first Falcon Heavy side boosters. We don't know how much refurbishment that required, but given the risk to LC-39A if that launch goes wrong, I think we can assume that they are completely confident in that booster being safe to refly. And if it's safe to refly that means their other landed GTO boosters might also be available for re-use, even if that has to just be for launching their own satellites, if their customers aren't comfortable with flying on them. Which means they are building up quite a stockpile of boosters, unless they have already quietly started scrapping some of them. So it's possible that in Adelaide when Elon talked about building up a stock of boosters, he may have also meant some of the older block 3 and 4 stages, which they could use to loft some of their Starlink constellation.

iii) As AbuSimbel points out; they wont want to waste precious time and resources refurbishing more demanding older boosters if they think they have more block 5 flight lifetimes available than they could ever use, but given that they can't be certain exactly when BFR/BFS will be ready to assume the full launch workload it's also possible that they will choose to eke out every last flight they can get out of the block 3 and 4 boosters, in order to be keep as many block 5 flights in reserve as they can. It could also simply be good business, if the cost of those refurbishments is sufficiently low.

So taking all the above into account, it's possible that SpaceX are still keen to recover and stockpile even more boosters, and that the decision not to this time is simply a trade to allow them to achieve something else instead.

Online Lar

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welcome to the forum, UKobserver.  Great first post. I think you nicely synthesized a lot of the previous speculation into one nice easy to digest package of analysis.
"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk
"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Offline saliva_sweet

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1. That in return for re-using a pre-flown booster they have promised Matt Desch delivery to a slightly higher initial orbit, so as to reduce the time needed to raise the satellites into their final orbits, and;

2. That they may indeed have traded some or all of the recovery margin to test out something else which requires adding mass to the stage, such as a further evolution of the fairing recovery, as cscott postulated, and which is made more likely by the fairing recovery ship having been switched to the west coast. It could be that they have accepted a heavier recoverable fairing design for Block 5, but want to test it now, and can only do so on a less-powerful block 3 booster by sacrificing margin somewhere else, such as removing the weight of the landing legs and grid fins.

We know that Iridium flights are RTLS-able on block 4 (which AFAIK wasn't supposed to be much more powerful than block 3). That would imply that the recoverable fairing comes with a huge penalty if they need to fly block 3 expendably with it. There is also some L2 info that suggests that deals with Desch or margins are unlikely to be behind this decision.

Offline RocketLover0119

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As funny as this sounds could the reason for the expended booster be they are running out of storage?
"The Falcon has landed"

As funny as this sounds could the reason for the expended booster be they are running out of storage?

That's possible, but it's mostly to clear out the old Block III boosters to make way for Block IV and V.
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Offline RocketLover0119

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Another thing I am interested in seeing is what this will look like. Desch mentioned in a tweet this would have the soot from its last landing and minus the legs and fins, should be very interesting
"The Falcon has landed"

Online mme

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Expend the booster to save money.  Hmmmm. 

 - Ed Kyle
It's disappointing to me but how is expending a booster you plan to never use again confusing to people?  I'd prefer they recover it and analyze/recycle it. But they didn't ask me.
Space is not Highlander.  There can, and will, be more than one.

Online AncientU

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I donít see SpaceX tossing away a booster just because they donít need it. That runs exactly opposite of the mindset theyíre trying to establish. A few $100k to recover a core is absolutely nothing in the larger framework of mission cost - compare that to the value of underscoring the important of recovery and reuse to their customers.

If I understand you correctly, you're saying that SpaceX would spend a few 100k recovering a booster they don't need so that customers don't think they're going soft on re-use? After 20 previous successful recoveries, including the last 16 consecutive attempts? And on a flight using a flight proven booster?

I think we'll have to agree to disagree on that one.
Feel free. But I suppose with your mindset you see zero value in the returned booster. That's fine - but I see value in:

- Post flight examination of entire system
- Reuse of sub systems such as gimbal control system, hydraulic systems, grid fin actuators and the fins themselves (even if AL), engine control modules, Merlin components (at $1,000,000 for each M1D you say that getting parts off even a few engines won't cover the cost of recovery?)
- Maintaining the path that SpaceX has worked so hard to establish.


Again - disagree all you want, but I maintain it's fatally shortsighted...

Could be that they believe that they are at point of diminishing returns on examining earlier-than-Block 5 boosters. 
That's great news (if it is true).

Certainly a reason to not expend more funds and time...
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Online AncientU

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Expend the booster to save money.  Hmmmm. 

 - Ed Kyle

You so want to be right about the folly of reusable boosters... but you're not.
"If we shared everything [we are working on] people would think we are insane!"
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Offline wannamoonbase

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As funny as this sounds could the reason for the expended booster be they are running out of storage?

That's possible, but it's mostly to clear out the old Block III boosters to make way for Block IV and V.

Bingo.  Itís not a first flight booster.  This makes sense given they are only flying each booster 2 times right now.

Recovery is cool, but it Takes considerable resources (maybe a million or two) and they donít need them piling up.  So why not give Iridium the most boost possible.
Excited to be finally into the first Falcon Heavy flow, we are getting so close!

Online Comga

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Quote
SpaceX spokesperson confirms online discussions (and comments by @IridiumBoss ) there will be no attempt to land the Falcon 9 first stage on Fridayís launch. ďThese are case by case decisions and are based on mission requirements and the needs of our manifest.Ē

https://twitter.com/jeff_foust/status/943269599302127617
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline Arb

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If there is discussion on SpaceX donating equipment for display, could someone point to it?
Can't provide a reference (it was some years ago) but my recollection is that when asked about donating a recovered core to the National Air and Space Museum, Musk replied along the lines of "Sure, if they pay for it".

Offline RocketLover0119

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On the flip side, i wanna hear what you all think about the new equipment added on mr. steven, i think its (obviously) for fairing recover, but the big poles that have been installed are interesting, I personally think a net will be installed and the fairing will parachute on to it, if this is the case, i hope it is shown on the webcast

all credit to reddit user vshie
« Last Edit: 12/20/2017 12:15 AM by RocketLover0119 »
"The Falcon has landed"

Offline craigcocca

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Mr Steven is still in port  as of the timestamp of this post
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Online edkyle99

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Expend the booster to save money.  Hmmmm. 

 - Ed Kyle
You so want to be right about the folly of reusable boosters... but you're not.
I've never called it "folly".  They may well be on a path to making partial reuse pay, eventually, but what I have been saying is that they are not there yet.  Throwing away a first stage on purpose during only its second flight (both lower energy LEO missions, BTW) is proof. 

 - Ed Kyle
« Last Edit: 12/20/2017 01:03 AM by edkyle99 »

Online Lar

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Expend the booster to save money.  Hmmmm. 

 - Ed Kyle
You so want to be right about the folly of reusable boosters... but you're not.
I've never called it "folly".  They may well be on a path to making partial reuse pay, eventually, but what I have been saying is that they are not there yet.  Throwing away a first stage on purpose during only its second flight (both lower energy LEO missions, BTW) is proof. 

 - Ed Kyle
it's proof of nothing other than a relentless focus on cost.

It's a block 3. So last week. Old engines. They are swimming in cores and don't need it. Only you could turn an actual advantage into your apparent disadvantage.
"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk
"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Offline kirghizstan

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Expend the booster to save money.  Hmmmm. 

 - Ed Kyle
You so want to be right about the folly of reusable boosters... but you're not.
I've never called it "folly".  They may well be on a path to making partial reuse pay, eventually, but what I have been saying is that they are not there yet.  Throwing away a first stage on purpose during only its second flight (both lower energy LEO missions, BTW) is proof. 

 - Ed Kyle


What if they are simply moving away from supporting that F9 block in the interest of commonality?  That block might have higher reuse costs and in the long run they have no use for continuing to support it. 

Online Lar

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On the flip side, i wanna hear what you all think about the new equipment added on mr. steven, i think its (obviously) for fairing recover, but the big poles that have been installed are interesting, I personally think a net will be installed and the fairing will parachute on to it, if this is the case, i hope it is shown on the webcast

all credit to reddit user vshie

The place to discuss that is the Fairing Reuse thread. http://forum.nasaspaceflight.com/index.php?topic=37727
"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk
"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Offline RocketLover0119

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Ah, thanks!


On the flip side, i wanna hear what you all think about the new equipment added on mr. steven, i think its (obviously) for fairing recover, but the big poles that have been installed are interesting, I personally think a net will be installed and the fairing will parachute on to it, if this is the case, i hope it is shown on the webcast

all credit to reddit user vshie

The place to discuss that is the Fairing Reuse thread. http://forum.nasaspaceflight.com/index.php?topic=37727
"The Falcon has landed"

Offline envy887

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Expend the booster to save money.  Hmmmm. 

 - Ed Kyle
You so want to be right about the folly of reusable boosters... but you're not.
I've never called it "folly".  They may well be on a path to making partial reuse pay, eventually, but what I have been saying is that they are not there yet.  Throwing away a first stage on purpose during only its second flight (both lower energy LEO missions, BTW) is proof. 

 - Ed Kyle
There is no evidence that even just 2 launches per booster wouldn't quickly pay back the initial investment in reuse. If they save $20M net per reuse, they are already at $100M saved in only 8 months, with the reuse rate rapidly increasing.

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