Author Topic: SpaceX Falcon 9 : Iridium NEXT Flight 4 : December 22/23, 2017 : Discussion  (Read 104258 times)

Online abaddon

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If only we had a reporter on this site who could ask SpaceX and get a direct answer to the question of why they are expending the booster.

Oh, wait: https://forum.nasaspaceflight.com/index.php?topic=44273.msg1761371#msg1761371
« Last Edit: 12/20/2017 02:31 PM by abaddon »

Online LouScheffer

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Expend the booster to save money.  Hmmmm. 

Exactly!  With recoverable rockets, there are factors in play that never occur with expendables:
 * Storage costs
 * Refurbishment costs
 * Inventory management
 * Technical improvement of new versions vs lower cost of old versions.
The phrase "paradigm shift" is overused, but I think this is a legitimate example.

Every other transportation industry - trucking, rental cars, air transport, constantly balances these factors.   And at some point it's cheaper to expend than to keep.

Take air transport, for example.  Airlines hate to store planes they are not using.  They cost money and create no revenue, so they dispose of them as quickly as possible.  Airlines worry a great deal about refurbishment costs - that's exactly why they dispose of them right before a costly D check.  They worry about inventory - they will, for example, get rid of all their MD-80s so they can fly just one plane, a 737 (made up example).  They get rid of old planes that are working perfectly well since newer ones have better fuel economy.  But even though disposing of a plane is sometimes a way to save money, they still use each airplane more than once.  It's not a contradiction.

Note that every one of these concerns is now very relevant to SpaceX.  Boosters cost money to store, money and effort to refurbish, a mix of Block 3,4 and 5 creates headaches, and the new Block 5s offer better performance and re-use.  So sometimes SpaceX will indeed save money by throwing one away.  It's a sign that SpaceX is now operationally bracketing the economics of re-use.  Is it at least sometimes cheaper to re-use?  Apparently, since they keep doing it.   Is is always cheaper to re-use?  No, as there are costs to re-use as well.   To me, this is a strong sign that SpaceX is treating re-use as economic exercise, and not a religious rite. 

Ironically, tossing a booster every so often strongly implies that re-use is economically justified.  It means they have no philosophical, practical, or operational reasons to avoid splashing them. So when they choose to re-use them, they must believe the advantages outweigh the costs.

Offline cscott

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Matt Desch refutes specific suggestions made to him of something different about NEXT 4 orbits:


Quote
Wrong guess. ;-) We are polar and need no doglegs, thank you!
https://twitter.com/IridiumBoss/status/943212004646539265

Hmm, not sure if this is implying that there might be a different, correct guess ... ?!


It's pretty clear to me that the reason is to buy mass for the fairing recovery experiment (see the pictures posted of fairing recovery ship GO Mr. Steven in the Port of LA), but @IridiumBoss isn't allowed to say that (or is just being polite by not spoiling SpaceX's announcement).  That explains his coy answers.
« Last Edit: 12/20/2017 02:29 PM by cscott »

Online gongora

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It's pretty clear to me that the reason is to buy mass for the fairing recovery experiment (see the pictures posted of fairing recovery ship GO Mr. Steven in the Port of LA), but @IridiumBoss isn't allowed to say that (or is just being polite by not spoiling SpaceX's announcement).  That explains his coy answers.

It's really not clear to me that expending the booster has anything to do with fairing recovery.  In fact, I think that is pretty far fetched.  It also has nothing to do with the payload or orbit, it's the same payload and orbit as the last three Iridium launches.

Offline FinalFrontier

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Expend the booster to save money.  Hmmmm. 

Exactly!  With recoverable rockets, there are factors in play that never occur with expendables:
 * Storage costs
 * Refurbishment costs
 * Inventory management
 * Technical improvement of new versions vs lower cost of old versions.
The phrase "paradigm shift" is overused, but I think this is a legitimate example.

Every other transportation industry - trucking, rental cars, air transport, constantly balances these factors.   And at some point it's cheaper to expend than to keep.

Take air transport, for example.  Airlines hate to store planes they are not using.  They cost money and create no revenue, so they dispose of them as quickly as possible.  Airlines worry a great deal about refurbishment costs - that's exactly why they dispose of them right before a costly D check.  They worry about inventory - they will, for example, get rid of all their MD-80s so they can fly just one plane, a 737 (made up example).  They get rid of old planes that are working perfectly well since newer ones have better fuel economy.  But even though disposing of a plane is sometimes a way to save money, they still use each airplane more than once.  It's not a contradiction.

Note that every one of these concerns is now very relevant to SpaceX.  Boosters cost money to store, money and effort to refurbish, a mix of Block 3,4 and 5 creates headaches, and the new Block 5s offer better performance and re-use.  So sometimes SpaceX will indeed save money by throwing one away.  It's a sign that SpaceX is now operationally bracketing the economics of re-use.  Is it at least sometimes cheaper to re-use?  Apparently, since they keep doing it.   Is is always cheaper to re-use?  No, as there are costs to re-use as well.   To me, this is a strong sign that SpaceX is treating re-use as economic exercise, and not a religious rite. 

Ironically, tossing a booster every so often strongly implies that re-use is economically justified.  It means they have no philosophical, practical, or operational reasons to avoid splashing them. So when they choose to re-use them, they must believe the advantages outweigh the costs.

In this case its simply this one

 * Inventory management

Block 3 is already obsolete by one generation, soon to be by two generations. There is no reason to retain Block 3 boosters.
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Online stcks

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It's pretty clear to me that the reason is to buy mass for the fairing recovery experiment (see the pictures posted of fairing recovery ship GO Mr. Steven in the Port of LA), but @IridiumBoss isn't allowed to say that (or is just being polite by not spoiling SpaceX's announcement).  That explains his coy answers.

That logic just doesn't make sense. The Iridium missions are not on the edge of recoverability like a 5.5mt GTO mission. There is margin enough to perform a boostback, long re-entry burn and a single engine landing burn. In addition, fairing recovery has been attempted on heavy GTO missions before.. with recovery hardware. The recovery hardware would have to be extremely dense and heavy in order to affect the launch so drastically that expendable F9 performance would be required. It doesn't add up.

Offline Andy Smith

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Or itís a combination of inventory management and the proposed second stage recovery experiment which is now unlikely to be taking place on FH?

Online gongora

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There was a comment on Reddit referencing a comment by The Roadie on Facebook saying the west coast ASDS isn't even operational right now (something about scavenging parts to repair the east coast ASDS after the fire.)  That and inventory management are far more likely reasons for expending the booster.

Offline cscott

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Hey, you guys may be totally right. Maybe I'm putting the cart before the horse and the JRtI issues are the cause, and the experiments are how SpaceX is making lemonade from its lemons.

I still think the experiments are the reason @IridiumBoss is being coy in his responses, though.  He knows a bit more about the lemonade than he can say.

Online gongora

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I still think the experiments are the reason @IridiumBoss is being coy in his responses, though.  He knows a bit more about the lemonade than he can say.

Matt isn't being "coy" in his responses.  First stage recovery isn't his business.  It's not something he would talk about.  His replies said that his payload isn't the reason for expending the booster.  That is all he would be expected to say on the subject.

Offline zubenelgenubi

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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".

If true, what a great way to unnecessarily burn a bridge, Elon. :(

Besides, with a donation of this scale, one should get two big, juicy, high-profile public events at the museum--one public, one private--commemorating the donation/display of the new artifact.
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Offline Lar

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I still think the experiments are the reason @IridiumBoss is being coy in his responses, though.  He knows a bit more about the lemonade than he can say.

Matt isn't being "coy" in his responses.  First stage recovery isn't his business.  It's not something he would talk about.  His replies said that his payload isn't the reason for expending the booster.  That is all he would be expected to say on the subject.

As I noted, we fans are badgering him about it, and he is taking it all with very good graces (he was polite in his reply to me), because he's a good guy. I thinl he gets that we fans are excited and curious and want to put it all together from the few puzzle pieces we can see. So he's being helpful.... but he is saying no more than it is his place to say. Good on him. He's a good man who is a staunch friend of SpaceX.
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Online nacnud

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There was a comment on Reddit referencing a comment by The Roadie on Facebook saying the west coast ASDS isn't even operational right now (something about scavenging parts to repair the east coast ASDS after the fire.)  That and inventory management are far more likely reasons for expending the booster.

That makes sense, it could also be a good use of the Block 3 boosters going forwards, i.e. if you have to expend a booster because the recovery assets are down send a Block 3.

Offline rabe0070

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If only we had a reporter on this site who could ask SpaceX and get a direct answer to the question of why they are expending the booster.

Oh, wait: https://forum.nasaspaceflight.com/index.php?topic=44273.msg1761371#msg1761371

I'm confused why this response was not sufficient and we are still talking about why they are not recovering it. Maybe they are using this opportunity to test something, but the main reason is to clear out Block 3 inventory.

Online envy887

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So why not give Iridium the most boost possible.

That's not a GEO launch. The satellites go to their initial orbit and don't need any additional boost beyond that.

They might, if an engine goes out on the way up. See CRS-1. Not likely, but it never hurts to have extra margins. Margin on the way up is a lot more useful than an old booster in a scrapyard.

Offline Comga

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If only we had a reporter on this site who could ask SpaceX and get a direct answer to the question of why they are expending the booster.

Oh, wait: https://forum.nasaspaceflight.com/index.php?topic=44273.msg1761371#msg1761371

Of please, please, please!
Enough of this back and forth. No one is saying anything new.
Can we please let it rest until a direct source tells us which of these theories is good and which are bogus?
Letís trust Chris G to ask this question so it gets answered.
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline 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.

They don't need to analyse it. They have already recovered (and analyzed) boosters 20 times, 3 of them being re-flights. SpaceX right now has a huge database on booster wear-and-tear, and the information in that database has been essential for informing the design of Falcon 9 Block 5. In stead of analyzing yet another old Block 3 it is time to get the first Block 5 off the ground and validate its design.

One of the essentials of working agile (like SpaceX does) is never to get stuck in the past. Always move forward. That's what SpaceX is doing. Block 3 has been analyzed to death and is yesterday's booster. Time to let go of it.
Also, it doesn't help that SpaceX has no storage space for all those old booster. They've already begun dumping some of them in the boneyard section of McGregor.
I agree 100%.  Block 3 is dead.  Long live Block 5.
Space is not Highlander.  There can, and will, be more than one.

Offline mme

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If only we had a reporter on this site who could ask SpaceX and get a direct answer to the question of why they are expending the booster.

Oh, wait: https://forum.nasaspaceflight.com/index.php?topic=44273.msg1761371#msg1761371

Of please, please, please!
Enough of this back and forth. No one is saying anything new.
Can we please let it rest until a direct source tells us which of these theories is good and which are bogus?
Letís trust Chris G to ask this question so it gets answered.
We don't need to go back and forth, it's answered in abaddon's link above.  Quoting it because abaddon just lined and people don't always follow links.

Matt Desch confirms no booster recovery.ŚÁ
https://twitter.com/IridiumBoss/status/943153072850776064


Quote
HŲchstErbaulich @HochstErbaulich
Hey @IridiumBoss will the Falcon 9 core for Iridium-4 be recovered? There are rumors that the first stage has no recovery equipment installed.

Matt Desch @IridiumBoss
Replying to @HochstErbaulich
No, I understand it won't be

For context, I'm told this is due to a desire to start clearing the Block 3 booster stock in favor for Block 4s and eventual Block 5s
Space is not Highlander.  There can, and will, be more than one.

Offline jpo234

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So why not give Iridium the most boost possible.

That's not a GEO launch. The satellites go to their initial orbit and don't need any additional boost beyond that.

They might, if an engine goes out on the way up. See CRS-1. Not likely, but it never hurts to have extra margins. Margin on the way up is a lot more useful than an old booster in a scrapyard.

So you suggest that SpaceX plans to expend the booster because they think that they might lose an engine on this flight?

I very much doubt that this is the reason.
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Online envy887

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So why not give Iridium the most boost possible.

That's not a GEO launch. The satellites go to their initial orbit and don't need any additional boost beyond that.

They might, if an engine goes out on the way up. See CRS-1. Not likely, but it never hurts to have extra margins. Margin on the way up is a lot more useful than an old booster in a scrapyard.

So you suggest that SpaceX plans to expend the booster because they think that they might lose an engine on this flight?

I very much doubt that this is the reason.

They might lose an engine leading to a performance shortfall. Leaving off the recovery hardware increases the margins available for the primary mission. Those are both facts. That those facts influenced the decision to not recover is just my opinion. There are obviously other reasons as well, and most likely no single deciding factor.

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