Author Topic: SpaceX Falcon 9 : Iridium NEXT Flight 4 : December 22/23, 2017 : Discussion  (Read 93034 times)

Online 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"

Offline IanThePineapple

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"

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.
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.
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Online 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.
SpaceX, just a few things planned for 2018: FH, Starlink Prototypes, Block 5, Dragon 2, Increased launch rate.

Offline 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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Offline 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.
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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. 

Offline 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"

Online 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.

Offline Lar

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General reuse economics is probably off topic here. I think there's a tread called Economics of Reuse or something.
"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

Online cscott

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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".
There are at least three recovered boosters on display (or planned to be): one outside SpaceX hq in Hawthorne, one for the KSC rocket garden ("in the next few months" I was told when I was there this summer), and one outside the SpaceX launch and landing control center across (and up the road) from Fishlips in Port Canaveral.  Other than the one in the KSC rocket garden, all are free and accessible by the public.

Ob. on-topic note: no recovery doesn't necessarily mean no grid fins.

I wouldn't be surprised to see Ti grid fins on this flight, in fact.

Also: different iridium flights are heading to different orbits with different inclinations.  Good margins for flight #1 don't *necessarily* mean the margins on flight #4 are large.

EDIT: all iridium satellites are in the same inclination, just different phasing.  They have different hosted payloads, but I don't know if that's enough mass to be significant for this discussion.
« Last Edit: 12/20/2017 02:52 AM by cscott »

Offline Jcc

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Ok, so we have some theories about expending the booster because they don't need it, don't have a place to store it, etc., and some thought about doing something extraordinary in terms of fairing recovery that requires the performance or maybe the ships.

 Then there's the question of them actually needing the extra performance for contractual reasons, because they promised a higher orbit to reduce time to get the satellites into service. What about orbital plane, will this set of satellites require a greater plane change?

We may learn more once the press kit is released, if it has first stage burn time and target orbits that show the need for more performance.

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