Author Topic: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION  (Read 539019 times)

Online Comga

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #540 on: 01/05/2018 03:03 PM »
It will be ~46 deg F tonight at 8 PM EST at the Cape.
~50 tomorrow and ~60 Sunday
SpaceX may be waiting for the weather to warm up.
Sounds odd, to be honest, but could that be a contributor?
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline e of pi

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #541 on: 01/05/2018 03:29 PM »
It will be ~46 deg F tonight at 8 PM EST at the Cape.
~50 tomorrow and ~60 Sunday
SpaceX may be waiting for the weather to warm up.
Sounds odd, to be honest, but could that be a contributor?
I don't know if it's so much the absolute temperature as the winds created by the shear masses of air moving around with the disruption that's yanking the jet stream down and creating this cold snap, and the implications for upper level winds during launch. There may be some desire to see how the new LC-40 hardware and the Falcon 9 system are effected in pad ops by the cold in a safer environment than trying to launch through it, though--it's a bit of a unique opportunity to look for any unanticipated breakpoints for the future, but I know I'd rather they wait a few days and find GSE faults in a WDR than in a failed launch.

Offline toruonu

On a. Rief glance I didn’t find the launch window for tomorrow’s launch

Offline gongora

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #543 on: 01/06/2018 05:15 PM »
On a. Rief glance I didn’t find the launch window for tomorrow’s launch

8-10pm EST (UTC-5).  The top post in the thread shows the start of the launch window.

Offline Elthiryel

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #544 on: 01/06/2018 08:25 PM »
The new press kit has been released (available in the updates thread). I've decided to look for differences between the old and the new press kit and this is what I've found:

1. The old one stated that "SpaceX’s Falcon 9 rocket will deliver the Zuma spacecraft to low-Earth orbit.". The new one says that "SpaceX’s Falcon 9 rocket will deliver the Zuma spacecraft to orbit". So LEO removed.
2. Falcon 9 description is a bit more detailed, and there is a statement that "Falcon 9 is the first orbital class rocket capable of reflight." and that "SpaceX believes rocket reusability is the key breakthrough needed to reduce the cost of access to space and enable people to live on other planets."
3. Several events are offset by a few seconds!

Old timeline:
Quote
00:01:10 Max Q (moment of peak mechanical stress on the rocket)
00:02:16 1st stage main engine cutoff (MECO)
00:02:19 1st and 2nd stages separate
00:02:21 2nd stage engine starts
00:02:30 1st stage boostback burn begins
00:03:08 Fairing deployment
00:06:09 1st stage entry burn begins
00:07:51 1st stage landing

New timeline:
Quote
00:01:16 Max Q (moment of peak mechanical stress on the rocket)
00:02:20 1st stage main engine cutoff (MECO)
00:02:24 1st and 2nd stages separate
00:02:25 2nd stage engine starts
00:02:33 1st stage boostback burn begins
00:03:08 Fairing deployment
00:06:15 1st stage entry burn begins
00:07:56 1st stage landing
GO for launch, GO for age of reflight

Online ZachS09

Could these time differences indicate that Falcon 9 will fly a more flattened trajectory?

I ask that because the new MECO time is four seconds later than the original time (140 seconds compared to 136 seconds).
« Last Edit: 01/06/2018 08:38 PM by ZachS09 »
"Liftoff of Falcon 9: the world's first reflight of an orbital-class rocket."

Offline ChrisGebhardt

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #546 on: 01/06/2018 09:16 PM »
Everyone seems to assume that the Zuma mission was in the works for a while, but kept secret until 30 days before launch. Example:  SpaceX adds mystery “Zuma” mission, Iridium-4 aims for Vandenberg landing

But what if the mission did not even exist before then?


Except that our article clearly says Zuma's launch contract was established in 2015.    ;) https://www.nasaspaceflight.com/2018/01/spacex-falcon-9-launch-clandestine-zuma-satellite/
« Last Edit: 01/06/2018 09:24 PM by ChrisGebhardt »

Offline ChrisGebhardt

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #547 on: 01/06/2018 09:19 PM »
Could these time differences indicate that Falcon 9 will fly a more flattened trajectory?

I ask that because the new MECO time is four seconds later than the original time (140 seconds compared to 136 seconds).

The adjusted times could be trajectory related or related to month of year of launch.  Winter months produce a thicker lower atmosphere and thus the rocket has to work harder to get through it.  Shuttle compensated for this by having "winter SRBs" that had their prop poured in a configuration to produce greater thrust but shorter burn time.  As Flacon 9 is a liquid rocket, a longer burn time for a winter month launch mission would make sense.  And given the atmospheric setup over Florida of the last week, this might be the case.
« Last Edit: 01/06/2018 09:20 PM by ChrisGebhardt »

Offline cppetrie

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #548 on: 01/06/2018 09:31 PM »
Could these time differences indicate that Falcon 9 will fly a more flattened trajectory?

I ask that because the new MECO time is four seconds later than the original time (140 seconds compared to 136 seconds).

The adjusted times could be trajectory related or related to month of year of launch.  Winter months produce a thicker lower atmosphere and thus the rocket has to work harder to get through it.  Shuttle compensated for this by having "winter SRBs" that had their prop poured in a configuration to produce greater thrust but shorter burn time.  As Flacon 9 is a liquid rocket, a longer burn time for a winter month launch mission would make sense.  And given the atmospheric setup over Florida of the last week, this might be the case.
Very interesting factoid. Thanks for that! I’d never considered the effect of season and its associated atmospheric density changes as a factor. Certainly makes logical sense. This would be a rare instance where a payload was close enough to launching that a press kit was issued and then delayed long enough that seasonal atmospheric changes would effect the timeline seen in a revised press kit. All of that is accentuated by the unusually cold weather currently at the Cape.

Offline Raul

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #549 on: 01/06/2018 10:17 PM »
M1390 Zuma Launch Hazard Areas based on NOTMAR.
For comparison also former hazard area of planned 39a launch issued in November. Area A is now slightly shorter compare old one.

Stage2 debris area in Southern Indian Ocean.

Offline LouScheffer

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #550 on: 01/07/2018 12:04 AM »
Everyone seems to assume that the Zuma mission was in the works for a while, but kept secret until 30 days before launch. Example:  SpaceX adds mystery “Zuma” mission, Iridium-4 aims for Vandenberg landing

But what if the mission did not even exist before then?


Except that our article clearly says Zuma's launch contract was established in 2015.    ;) https://www.nasaspaceflight.com/2018/01/spacex-falcon-9-launch-clandestine-zuma-satellite/
Again, I don't think this is a contradiction.  Your article states (bold mine):
Quote
According to source documentation, Zuma’s launch contract – which did not specify a launch date – was established with SpaceX in 2015.
For a first pass at a responsiveness test, Agency X might grant SpaceX a contract for a booster, and a launch, but nothing else - no payload specified, no date, no orbit, maybe not even which coast.   Then, for example, on 1 November 2017, they call up and say "Here's your payload , name is ZUMA.  Here's the orbit we want.  Get it into orbit within 30 days."

This is exactly consistent with what we saw, your article, and the NAS report from 2010 recommending the Air Force set up responsiveness objectives.  It explains why we heard nothing from SpaceX before 1 November - they did not know.  And (my opinion only) this seems like very reasonable first pass at responsiveness by the government.

Offline crandles57

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #551 on: 01/07/2018 11:29 AM »

The adjusted times could be trajectory related or related to month of year of launch.  Winter months produce a thicker lower atmosphere and thus the rocket has to work harder to get through it.  Shuttle compensated for this by having "winter SRBs" that had their prop poured in a configuration to produce greater thrust but shorter burn time.  As Flacon 9 is a liquid rocket, a longer burn time for a winter month launch mission would make sense.  And given the atmospheric setup over Florida of the last week, this might be the case.

More burn time and more fuel to get though thicker atmosphere makes sense.

Can we tell anything from Max q being 6 seconds later compared to MECO being only 4 seconds later?

Offline ChrisGebhardt

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #552 on: 01/07/2018 01:17 PM »
Everyone seems to assume that the Zuma mission was in the works for a while, but kept secret until 30 days before launch. Example:  SpaceX adds mystery “Zuma” mission, Iridium-4 aims for Vandenberg landing

But what if the mission did not even exist before then?


Except that our article clearly says Zuma's launch contract was established in 2015.    ;) https://www.nasaspaceflight.com/2018/01/spacex-falcon-9-launch-clandestine-zuma-satellite/
Again, I don't think this is a contradiction.  Your article states (bold mine):
Quote
According to source documentation, Zuma’s launch contract – which did not specify a launch date – was established with SpaceX in 2015.
For a first pass at a responsiveness test, Agency X might grant SpaceX a contract for a booster, and a launch, but nothing else - no payload specified, no date, no orbit, maybe not even which coast.   Then, for example, on 1 November 2017, they call up and say "Here's your payload , name is ZUMA.  Here's the orbit we want.  Get it into orbit within 30 days."

This is exactly consistent with what we saw, your article, and the NAS report from 2010 recommending the Air Force set up responsiveness objectives.  It explains why we heard nothing from SpaceX before 1 November - they did not know.  And (my opinion only) this seems like very reasonable first pass at responsiveness by the government.

Please read our articles about this.  You are saying that we assume this mission was in the works for years but unknown to everyone including SpaceX until 30 days before for launch.  It is a fact that Zuma was in the works between Northrop Grumman and SpaceX since 2015 - code name and all.  That is a fact not speculation.  It is also a fact – as we have reported – that Northrop Grumman communicated the launch date of 1–30 November 2017 to SpaceX in April 2017 and that SpaceX chose not to release that information.  It is also a fact that SpaceX didn't release the first mention of Zuma.  We did on this site by finding the FCC communication launch license.  Again, this is fact, not speculation.  Your assertion that all of this was secretive to all parties involved until 30 days before lift off is your own speculation, not fact... as SpaceX knew about this in 2015, knew the target launch date 7 months in adavamce, and filed the FCC license application more than 30 days before the launch.

You also omit the part of our articles and reporting detailing that the initial contract called for the launch booster to be B1046 and how the three flight proven missions assigned before Zuma's original launch date gives us B1043 for this mission - which points to a knowledge in the original contract that launch would occur around the time that booster B1046 would be ready.  So even there a notional NET date would have been known to SpaceX.

So, in short...
- SpaceX knew about this more than two years ago
- SpaceX knew it would be B1046 two years ago, which accounting for three assigned reflights last year before Zuma Nov launch window makes it B1043
- SpaceX knew in April 2017 that NG wanted a launch in November 2017
- SpaceX filed for a launch communications license with the FCC more than 30 days before launch target

None of this supports an assertion that no one, including SpaceX, knew of the launch date more than 30 days before launch.

Offline yokem55

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #553 on: 01/07/2018 02:44 PM »
Is it just me or do the landing legs look different?

Offline douglas100

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #554 on: 01/07/2018 03:33 PM »
Had a quick look. They seem the same to me.
Douglas Clark

Offline MP99

A full WDR would do the exact same things as a static fire except light the engines.

And that is in fact a MAJOR difference.

A WDR doesn't require the services of the range. In this case the WDR was a propellant loading test. IMO it is a safe guess that SpaceX only partially loaded the vehicle and didn't even bother pressurizing the tanks to flight pressure.

A Static Fire does require the range because a static fire is considered to be a potential launch, coming with all the hazards that are associated with an actual launch, such as having a fully fueled and fully pressurized vehicle.
I thought a WDR included pressurising the vehicle? Does it not?

Thanks, Martin

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Offline HVM

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #556 on: 01/07/2018 06:43 PM »
Is it just me or do the landing legs look different?

Maybe its just lighting condition (it is), but those really look flatter and missing the sharp triangular (cutaway by spin axes) outer 'crest'.
« Last Edit: 01/08/2018 12:09 AM by HVM »

Offline gongora

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #557 on: 01/07/2018 06:51 PM »
Is it just me or do the landing legs look different?

Maybe its just lighting condition, but those really look flatter and missing the sharp triangular (cutaway by spin axes) outer 'crest'.

I think the combination of angle and lighting.  Compare to this when it was on the pad at LC-39A:
https://forum.nasaspaceflight.com/index.php?topic=44175.msg1750258#msg1750258

Offline zubenelgenubi

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Re: SpaceX F9 : Zuma : January 7/8, 2018, CCAFS : DISCUSSION
« Reply #558 on: 01/07/2018 09:03 PM »
Updated Zuma elset estimates for an assumed 395 x 400 km orbit for various launch times at http://www.satobs.org/seesat/Jan-2018/0034.html , by Marco Langbroek.

Quote
...targeting the orbital plane of USA 276 has become viable near the end of the 1:00 - 3:30 UT launch window. The orbital plane of USA 276 passes over the launch site near 3:38 UT on January 8th.

However, the launch window is only 01:00 to 03:00 UTC, not 03:30 UTC, correct?
« Last Edit: 01/07/2018 09:05 PM by zubenelgenubi »
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Online ZachS09

However, the launch window is only 01:00 to 03:00 UTC, not 03:30 UTC, correct?

That's the right launch window: 01:00 to 03:00 UTC.

Never heard from SpaceX that the window extended another half-hour.
"Liftoff of Falcon 9: the world's first reflight of an orbital-class rocket."

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