Author Topic: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION  (Read 497860 times)

Offline SimonFD

If the payload adapter did fail, and LEO was achieved, is there a procedure for delaying a deorbit burn to troubleshoot?
With payloads, you would think that failure to separate would be worth waiting and looking at.
Perhaps there are orbital dynamics that make this nonsense, I don't know enough to speculate further.

I think the main limitation for on-orbit operations is the battery condition of the upper stage. I don't think it lasts very long (see discussion of FH demo mission).
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Online Norm38

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #861 on: 01/09/2018 11:53 AM »
I have a question for those with industry experience that I haven't seen asked, and I would like to speculate on.

Let's assume that the ONLY thing that went wrong, was separation failure.  Immediately after that, we have two functioning pre-programmed spacecraft that cannot communicate with each other, that think they are flying separately, but are still connected.

Zuma would begin firing thrusters to finalize its orbit.  Meanwhile S2 would fire its thrusters to target the de-orbit burn.  Two independent propulsion/guidance systems targeting two different orbits, connected together.

Who wins/loses that tug of war? Does that explain any of the observations we have, such as the "spiral"?
« Last Edit: 01/09/2018 01:02 PM by Norm38 »

Offline FutureMartian97

All of this talk saying how the payload failed to separate really makes me think of how BFR could've saved the day by simply bringing Zuma back to Earth for repairs

We know that NOTAMs are provided for areas where the second stage is supposed to brake up on re-entry. Does that mean that SpaceX must attempt re-entry at that specific space? Or could they choose to leave the second stage in orbit at that point?

Offline Kabloona

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #864 on: 01/09/2018 12:19 PM »
I have a question for those with industry experience that I haven't seen asked, and I would like to speculate on.

Let's assume that the ONLY thing that went wrong, was separation failure.  Immediately after that, we have two functioning pre-programmed spacecraft that cannot communicate with each other, that think they are flying separately, but are still connected.

Zuma would begin firing thrusters to finalize its orbit.  Meanwhile S2 would fire its thrusters to target the de-orbit burn.  Two independent propulsion/guidance systems targeting two different orbits, connected together.

Who wins/looses that tug of war? Does that explain any of the observations we have, such as the "spiral"?

Excellent question. Some of the answer depends on things we don't know. Usually the spacecraft has an electrical means of knowing it has separated (eg contact switch at the sep interface) which tells it to "wake up" and begin its mission. That is typically done in order to prevent the payload from mistakenly/prematurely trying to do its own thing while still attached to the upper stage.

But if separation doesn't occur and the contact switch at the sep plane doesn't open/close, the payload doesn't sense sep and doesn't "wake up" and try to begin on-orbit maneuvers. Assuming ZUMA is designed like a typical payload in that regard.

On the other side, the upper stage is typically pre-programmed to do a collision/contamination avoidance maneuver after payload sep, then deorbit itself. The only way this wouldn't happen is if the upper stage has its own (independent of payload's) separation indicator/sensor and a branch of flight computer instructions that gets chosen in case separation is not sensed. But that assumes there are any good alternative options available in case of failed separation. It's possible there aren't and that the upper stage is designed to issue a sep command and then continue on blindly with C/CAM and deorbit regardless.

In which case it's conceivable the payload remains attached and "dead" because it didn't receive its wake-up call from the separation indicator switch, while the upper stage continues its pre-programmed routine with the payload attached.
« Last Edit: 01/09/2018 12:24 PM by Kabloona »

Offline sghill

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #865 on: 01/09/2018 12:26 PM »
Lots of speculation that zuma was a satellite that failed and reentered around the same time as S2.

I'll add to the noise in a different direction by speculating that Zuma was a hypersonic vehicle, and that it functioned as planned.

Northrup Grumman has been in the hypersonic vehicle business for a long time, and indeed, they are hiring for hypersonic vehicle design engineers in Melbourne right now (check their HR site).

Just last spring, I saw one of their hypersonic cruise missile program trailers parked at a Busy Bee gas station on the way to the Cape with several security vehicle escorts.  When I saw it, I giggled to myself that their super secret program had its damn logo emblazoned all over the side of the trailer.

So, unless Zuma was really a satellite, everything else- including why no agency will own up to the launch- fits nicely with it being a vehicle test for NG.

« Last Edit: 01/09/2018 12:31 PM by sghill »
Bring the thunder Elon!

Offline Jim

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #866 on: 01/09/2018 12:34 PM »
How would stage separation fail? What are the common methods for separating payloads? Which might NG have used?

Miswired, bad ordnance, bad command, etc

Unfortunately, it's common that failures happen at the physical/electrical interface of two components supplied by different contractors...in this case (potentially) the payload adapter supplied by NG and (presumably) the separation command electrical harness by Space X. When one contractor supplies, say, the ordnance on the payload adapter, and the other contractor supplies the electrical connector that interfaces with it, a design error on one side won't necessarily be caught on the ground.

Such a case happened on TOS/ACTS mission on the Shuttle, where Lockheed Martin miswired the electrical connectors to the separation system supplied by a subcontractor, with the result that the sep system fired incorrectly in space, despite numerous preflight  fit checks, tests, etc, on the ground.
Which makes it all the more possible that the issue was precisely that-  we know that SpaceX conducted multiple wet dress rehearsals, plus the full static fire back in November... That being said, the wet dress rehearsals were all done without the payload/fairing attached, so that separation couldn't have been tested then... Makes me truly think that NG is at fault here... I just hope we get a little more clarification in the coming hours and days- tho my hopes of SpaceX not getting dragged through the mud in the media is a fools errand at best. Hopefully SpaceX is at least allowed to explain in some way to their actual customers that they're not at fault and that they did the job they were paid to do...

I truly wonder however if this will hurt or even destroy SpaceX's chances for future missions of this nature... especially when politics could possibly muck things up even further


On the Tech Crunch thing- they're owned by AOL... so it's probably down to quick lazy journalism...

Actual separation is never tested.  The signals to separate can be tested during WDR if there is something to record it.

Don't understand your point

Offline Jim

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #867 on: 01/09/2018 12:37 PM »
Remember that there are cameras on SpaceX vehicles taking video that we never get to see.  If this vehicle failed to separate, there is video IN ADDITION TO the telemetry.  Everybody within the classified loop would know very quickly that something had happened.  Meanwhile, we have the C.O. of the 45th Space Wing congratulating SpaceX and his people for a successful launch.  The classified nature of this mission makes it a magnet for those with an agenda.  The people being attacked cannot defend themselves.

Edit: for typo.

Those cameras would not be used on these missions

Offline woods170

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #868 on: 01/09/2018 12:40 PM »
Lots of speculation that zuma was a satellite that failed and reentered around the same time as S2.

I'll add to the noise in a different direction by speculating that Zuma was a hypersonic vehicle, and that it functioned as planned.

Northrup Grumman has been in the hypersonic vehicle business for a long time, and indeed, they are hiring for hypersonic vehicle design engineers in Melbourne right now (check their HR site).

Just last spring, I saw one of their hypersonic cruise missile program trailers parked at a Busy Bee gas station on the way to the Cape with several security vehicle escorts.  When I saw it, I giggled to myself that their super secret program had its damn logo emblazoned all over the side of the trailer.

So, unless Zuma was really a satellite, everything else- including why no agency will own up to the launch- fits nicely with it being a vehicle test for NG.



Not that I go along with your suggestion but it would be one explanation why NG furnished the payload adapter.

Offline Jim

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #869 on: 01/09/2018 12:44 PM »
Here's confirmation from Wired, November 2017

https://www.wired.com/story/spacexs-top-secret-zuma-mission-launches-today/

Quote
Veteran aerospace manufacturer Northrop Grumman built the payload, according to a document obtained by WIRED and later confirmed by the company. The company says it built Zuma for the US government, and its also providing an adapter to mate Zuma with SpaceXs Falcon 9 rocket. But thats where information starts tapering off.

A separately provided payload attach fitting (PAF) might explain why the fairing issue did not effect the Iridium launch in December. The fairing is attached to the PAF, which is then bolted to the second stage. An issue with a custom PAF and the fairing thus should not affect Iridium. Photo below showing SpaceX PAF and fairing.

No, wrong takeaway. 
SpaceX will always provide the PAF, the black cone that interfaces with the fairing.  The Payload Adaptor ( the cone that goes between the PAF and spacecraft) can be provided by SpaceX or the payload.

Offline su27k

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #870 on: 01/09/2018 12:45 PM »
Please stop speculating about Zuma. No one is going to say anything about it. If SpaceX's upcoming launches are not put on hold then we will know it was not SpaceX's fault.

Just for the sake of argument, could there be scenarios where SpaceX is at fault but can still pressing on with upcoming launches? For example what if the thing failed is unique to the Zuma mission, for example a special payload adapter just for Zuma (Yes I know there is a report saying NG provided the adapter, but given all the secrecy and confusion over this mission, it not inconceivable that that single report is in error), in which case all the missions not using this adapter can still go on?

Offline Jim

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #871 on: 01/09/2018 12:46 PM »
I'm curious why there wasn't mention of a failed solar panel deployment. "Dead on orbit" is an indicator. Maybe I'm too old and forgot that some engineer invented the impossible to fail solar panel?

There might not be any deployable solar arrays

Offline Jim

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #872 on: 01/09/2018 12:48 PM »
All of this talk saying how the payload failed to separate really makes me think of how BFR could've saved the day by simply bringing Zuma back to Earth for repairs

can't say that

Offline Paul_G

A good point on why NG came with their own payload adapter, but there was a callout at T+2.07 for someone to relinquish control of the camera(s). Was this referring to ground based cameras that would have shown stage sep, or rocket / payload adaptor based cameras that on other missions show the payload.

Paul
« Last Edit: 01/09/2018 12:50 PM by Paul_G »

Offline Orbiter

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #874 on: 01/09/2018 12:49 PM »
On the US Launch Report video, fairing separation is visible

At 3:24?

Yes, and it is right on time.

Press kit says "Fairing Deployment" at 3:08 mission elapsed time.
Launch occurs at 0:15 into the video.
Add 3:08 to that and you get 3:23 mission elapsed time.

At 3:24 (only a second later) we see the fairing fall past the S2. So, looks like fairing separation was right on time.

FWIW, I was tracking the launch in my 6" telescope in Tampa and I saw at least one fairing come off.
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Offline Jim

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #875 on: 01/09/2018 12:49 PM »
FYI, payload separation is usually detected by breakwires.

Offline MaxTeranous

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #876 on: 01/09/2018 12:50 PM »
Please stop speculating about Zuma. No one is going to say anything about it. If SpaceX's upcoming launches are not put on hold then we will know it was not SpaceX's fault.

Just for the sake of argument, could there be scenarios where SpaceX is at fault but can still pressing on with upcoming launches? For example what if the thing failed is unique to the Zuma mission, for example a special payload adapter just for Zuma (Yes I know there is a report saying NG provided the adapter, but given all the secrecy and confusion over this mission, it not inconceivable that that single report is in error), in which case all the missions not using this adapter can still go on?

No, because it calls into question the methods and processes which led to the use and installation of that special adaptor, methods and processes that are used on every flight regardless of payload.

Effectively if SpaceX carries on like nothing happened then the Zuma F9 performed correctly. There's no other explanation without full blown tinfoil hattery.

Offline woods170

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #877 on: 01/09/2018 12:51 PM »
we know that SpaceX conducted multiple wet dress rehearsals, plus the full static fire back in November... That being said, the wet dress rehearsals were all done without the payload/fairing attached, so that separation couldn't have been tested then... Makes me truly think that NG is at fault here...

Actual separation is never tested.  The signals to separate can be tested during WDR if there is something to record it.

To expand on Jim's usual terse post...
Spacecraft separation from a launch vehicle usually involves pyrotechnics.
You can't test pyrotechnics prior to launch. Testing them would set them off which would require replacement of the pyrotechnics.

It is the one reason why SpaceX primarily uses pneumatics for separation events, such as stage separation and fairing release.
However, the launcher-to-spacecraft separation plane is, per industry standard, usually equipped with a pyrotechnically-driven separation system.

But, failures of space-rated pyrotechnic devices are exceedingly rare.
« Last Edit: 01/09/2018 12:51 PM by woods170 »

Offline M.E.T.

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #878 on: 01/09/2018 12:51 PM »
What would SpaceX's disclosure rights be in terms of communicating with other prospective customers about the results of this mission? Would they be allowed to confirm to justifiably worried clients that this was a successful mission as far as SpaceX's role was concerned?

And if pressed, would they be allowed to specify why they are confident of that assertion? Or is the potential reputational damage associated with the current speculation a price SpaceX has to pay in exchange for top secret government contracts?

Surely there is a right to protect the company's image that should be balanced with the classified nature of the mission?
« Last Edit: 01/09/2018 12:53 PM by M.E.T. »

Offline woods170

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #879 on: 01/09/2018 12:52 PM »
What would be SpaceX's disclosure rights in terms of communicating with other prospective customers about the results of this mission? Would they be allowed to confirm to justifiably worried clients that this was a successful mission as far as SpaceX's role was concerned?

They already did that via their public statement.

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