Author Topic: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION  (Read 557830 times)

Offline andrewsdanj

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #1160 on: 01/11/2018 07:52 PM »
As a brief interlude from all of the speculation and tinfoilhattery... Did the landing seem rather 'sedate' to anyone else? I'm used to the tempo being 'wow-pad-weeeee-landed', this time there was a good 10 seconds from first seeing the pad to shutoff, and it sure seemed that there was still (residual) thrust on the ground for a couple of seconds before shutoff.

Probably just a trick of the light (or lack thereof), but it struck me as a more leisurely landing than we're used to!

Offline Nomadd

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #1161 on: 01/11/2018 07:56 PM »
 So, if the adapter did fail, would the satellite probably have been hopeless in a short time because it wouldn't have been able to extend solar arrays while latched to the stage? I'm just trying to make sense of the stage de-orbiting without deployment confirmation.
« Last Edit: 01/11/2018 07:57 PM by Nomadd »

Online JonathanD

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #1162 on: 01/11/2018 08:01 PM »
So, if the adapter did fail, would the satellite probably have been hopeless in a short time because it wouldn't have been able to extend solar arrays while latched to the stage? I'm just trying to make sense of the stage de-orbiting without deployment confirmation.

Stage 2 has limited battery life.  If you can't get the payload separated by the time Stage 2 needs to de-orbit, it goes down with the ship.
« Last Edit: 01/11/2018 08:01 PM by JonathanD »

Offline Ictogan

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #1163 on: 01/11/2018 08:08 PM »

Stage 2 has limited battery life.  If you can't get the payload separated by the time Stage 2 needs to de-orbit, it goes down with the ship.

Wouldn't it be better to just not deorbit the second stage if seperation of the satellite doesn't occur until planned deorbit time?

Offline envy887

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #1164 on: 01/11/2018 08:10 PM »
So, if the adapter did fail, would the satellite probably have been hopeless in a short time because it wouldn't have been able to extend solar arrays while latched to the stage? I'm just trying to make sense of the stage de-orbiting without deployment confirmation.

If deploy fails, the payload is toast anyway. It probably has a hard switch preventing it from powering on while attached to the stage (accidentally coming alive inside the fairing would be bad for all involved), and at the very least it won't perform as planned with 5 tonnes of Falcon hanging off its butt.

At that point your options are basically:
1) deorbit the stage and payload into the predefined hazard area or
2) let the stage die and the stage+payload deorbit randomly due to atmospheric drag, so it could hit a population center or worse crash where its classified secrets are accessible to a potentially hostile nation.
« Last Edit: 01/11/2018 08:25 PM by envy887 »

Online JonathanD

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #1165 on: 01/11/2018 08:17 PM »
Wouldn't it be better to just not deorbit the second stage if seperation of the satellite doesn't occur until planned deorbit time?

Definitely not.  See envy887's post above.

Offline Pete

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #1166 on: 01/11/2018 08:18 PM »
... Did the landing seem rather 'sedate' to anyone else?

Nope.
All RTLS landings will follow virtually the exact same trajectory.

Zuma's landing burn took the same time +-2 seconds as *all* of the previous RTLS landings..
(that i could find good youtube recordings of, to use as time measurements)

Visually comparing Zuma vs. CRS-13 and CRS-9, the speed of landing seemed identical.
The deployment timing and speed of the landing legs differ quite a bit though, go figure. Maybe this is what threw your speed sense off?

Offline lonestriker

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #1167 on: 01/11/2018 08:20 PM »
So, if the adapter did fail, would the satellite probably have been hopeless in a short time because it wouldn't have been able to extend solar arrays while latched to the stage? I'm just trying to make sense of the stage de-orbiting without deployment confirmation.

If deploy fails, the payload is toast anyway. It probably has a hard switch preventing it from powering on while attached to the stage (accidentally coming alive inside the fairing would be bad for all involved), and at the very least it won't perform as planned with 5 tonnes of Falcon hanging off its butt.

At that point your options are basically:
1) deorbit the stage and payload into the predefined hazard area or
2) let the stage die and deorbit randomly due to atmospheric drag, so it could hit a population center or worse crash where its classified secrets are accessible to a potentially hostile nation.

This is why the spooks need to fund BFR/BFS, so they can go up and fetch their multi-billion dollar failed satellite/space-plane/hypersonic-test-vehicle rather than let it burn up as the only option.

Online JonathanD

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #1168 on: 01/11/2018 08:23 PM »
Nope.
All RTLS landings will follow virtually the exact same trajectory.

Zuma's landing burn took the same time +-2 seconds as *all* of the previous RTLS landings..
(that i could find good youtube recordings of, to use as time measurements)

Visually comparing Zuma vs. CRS-13 and CRS-9, the speed of landing seemed identical.
The deployment timing and speed of the landing legs differ quite a bit though, go figure. Maybe this is what threw your speed sense off?

I have noticed that since they added the radar-reflective paint to LZ-1 the landings have looked "softer" -- maybe that's what he was referring to.

Offline envy887

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #1169 on: 01/11/2018 08:27 PM »
So, if the adapter did fail, would the satellite probably have been hopeless in a short time because it wouldn't have been able to extend solar arrays while latched to the stage? I'm just trying to make sense of the stage de-orbiting without deployment confirmation.

If deploy fails, the payload is toast anyway. It probably has a hard switch preventing it from powering on while attached to the stage (accidentally coming alive inside the fairing would be bad for all involved), and at the very least it won't perform as planned with 5 tonnes of Falcon hanging off its butt.

At that point your options are basically:
1) deorbit the stage and payload into the predefined hazard area or
2) let the stage die and deorbit randomly due to atmospheric drag, so it could hit a population center or worse crash where its classified secrets are accessible to a potentially hostile nation.

This is why the spooks need to fund BFR/BFS, so they can go up and fetch their multi-billion dollar failed satellite/space-plane/hypersonic-test-vehicle rather than let it burn up as the only option.

Or just turn around and land if sep fails.

Offline GWH

Nothing new in the linked article below, just some statements based on rumours.

Hey Chris G. - your twitter posts are now included in the reporting of Canada's most read news organization!
http://www.cbc.ca/news/technology/spacex-zuma-1.4477310

Offline JimO

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #1171 on: 01/11/2018 08:35 PM »
Excellent discussion. I'm looking at the Khartoum photos in a new light.
« Last Edit: 01/11/2018 08:36 PM by JimO »

Offline vanoord

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #1172 on: 01/11/2018 08:37 PM »
Sorry, recovered this from the pre-gardened thread on my laptop. Reckon it qualifies as discussion rather than party...

Quote
Quote from: LouScheffer on Today at 06:19 PM
Quote
Quote from: vanoord on Today at 04:48 PM
One question that does spring to mind is why NG provided the payload adaptor? Does that give an indication that the payload was sufficiently non-standard (conspiracy theorists can suggest hypersonic lifting bodies or whatever) that the usual SpaceX adaptor wasn't used?


I still think (though Chris Gebhardt does not) that this was a test of a faster response, more hands-off launch flow, as opposed to the monolithic integration and testing that has traditionally been used.

In this case, the government designs satellites to match exactly the specific public interface of launch vehicles.  The intention would be that they can build and store satellites, then when needed, give SpaceX, ULA, or BO a call, bolt it together, and have a new asset in space within weeks, instead of the usual years.

This would account for why NG built the payload adapter, the late announcement of the name, the short time from public notice to launch, and so on.  If it was the first time, this would probably be a test processing flow, more in the flavor of "lets do it the way we'd need to get a 30 day response", and not an actual, 30 day, fully decoupled flow on the first try.

If so, in some ways ZUMA was a success, as it revealed flow problems that need to be addressed.   But it failed in the way AMOS-6 static fire failed - since the test was thought to be almost certain to be successful, it was tried in a case where failure was very expensive, in an attempt to cut schedule and effort.

Unless there is something very odd about the way that the spacecraft joined the adaptor (see conspiracies) then the lesson has to be that if there is a perceived requirement to 'launch on need', the spacecraft should have a 'standard' adaptor at its base; and SpaceX (and ULA etc.) should be persuaded / paid to have a spare payload adaptor readily available to be used for such a mission?

Offline QuantumG

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #1173 on: 01/11/2018 08:48 PM »
The Zuma loss isn't just "rumors".  The reports were based on multiple sources, congressional and industry, who said they had been briefed on the failure.

... and as we've said, those people either don't have clearance (in which case they're repeating a rumour) or they do and they're risking federal prison why? Multiple sources is irrelevant if they're all repeating the same rumour.
I hear those things are awfully loud. It glides as softly as a cloud. What's it called? Monowhale!

Offline Jim

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #1174 on: 01/11/2018 08:50 PM »
Use of spacecraft provided adapter increases work and time vs using standardized adapters.

There are standardized sep systems for 37, 47 and 66 inch adapters.  Most commercial spacecraft buses use these.


Offline andrewsdanj

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #1175 on: 01/11/2018 08:56 PM »
Nope.
All RTLS landings will follow virtually the exact same trajectory.

Zuma's landing burn took the same time +-2 seconds as *all* of the previous RTLS landings..
(that i could find good youtube recordings of, to use as time measurements)

Visually comparing Zuma vs. CRS-13 and CRS-9, the speed of landing seemed identical.
The deployment timing and speed of the landing legs differ quite a bit though, go figure. Maybe this is what threw your speed sense off?

I have noticed that since they added the radar-reflective paint to LZ-1 the landings have looked "softer" -- maybe that's what he was referring to.

Yes indeeed, that's what I meant. The decelation over the final period SEEMED very progressive to a very soft touchdown. Nicely done. Maybe it's just becoming too routine seeing only one land at once...

Offline JimO

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #1176 on: 01/11/2018 09:02 PM »
Here's a draft of my report on the controversy over the June 2010 observation of the Falcon-9 venting second stage over SE Australia.

The relevance to Zuma is that the 2010 event clearly involved one plume, and the 2018 event over Khartoum was a double plume of much shorter duration.

Has the prop dump system been significantly upgraded, or do these differences indicate a fundamentally different nature of the two events?

Offline kerogre256

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #1177 on: 01/11/2018 09:06 PM »
I think this is best info we will get on that "zuma" mission I just wonder how long this twitt will be live.
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Matt Desch‏ @IridiumBoss
Replying to @TomMcCuin @SpaceX @ClearanceJobs

Tom, this is a typical industry smear job on the "upstart" trying to disrupt the launch industry.  @SpaceX didn't have a failure, Northrup Grumman did.  Notice that no one in the media is interested in that story.  SpaceX will pay the price as the one some will try to bring low.
1:23 pm - 11 Jan 2018
Replying to @IridiumBoss @SpaceX @ClearanceJobs

I wasn't trying to "blame" SpaceX as much as point out how difficult this stuff is. Yes, Northrop Grumman insisted on using their connector. I get it. But the point is, even powerhouses like SpaceX and NG can have mishaps, so keep that in mind when evaluating DPRK missile tech.
0 replies . 0 retweets 0 likes
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Offline Star One

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #1178 on: 01/11/2018 09:08 PM »
I think this is best info we will get on that "zuma" mission I just wonder how long this twitt will be live.
""""""""""""""""""""""""""""""""""""""""""""""
Matt Desch‏ @IridiumBoss
Replying to @TomMcCuin @SpaceX @ClearanceJobs

Tom, this is a typical industry smear job on the "upstart" trying to disrupt the launch industry.  @SpaceX didn't have a failure, Northrup Grumman did.  Notice that no one in the media is interested in that story.  SpaceX will pay the price as the one some will try to bring low.
1:23 pm - 11 Jan 2018
Replying to @IridiumBoss @SpaceX @ClearanceJobs

I wasn't trying to "blame" SpaceX as much as point out how difficult this stuff is. Yes, Northrop Grumman insisted on using their connector. I get it. But the point is, even powerhouses like SpaceX and NG can have mishaps, so keep that in mind when evaluating DPRK missile tech.
0 replies . 0 retweets 0 likes
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I think this sums things up very neatly. TBH I reckon we need look no further than what’s said here.

Offline QuantumG

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #1179 on: 01/11/2018 09:14 PM »
I think this sums things up very neatly. TBH I reckon we need look no further than what’s said here.

He has no clue if there even was a failure. He too is repeating the rumour that they did.

I hear those things are awfully loud. It glides as softly as a cloud. What's it called? Monowhale!

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