Author Topic: The SpaceX Scrubs thread  (Read 124186 times)

Offline Jim

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Re: The SpaceX Scrubs thread
« Reply #40 on: 01/07/2015 01:12 PM »
I had one person telling me on another board because a SpaceX mission was originally proposed to lift off in February but was re-scheduled to a later date in the year for (whatever reason) that means the mission was late. 

http://www.nasa.gov/home/hqnews/2012/jul/HQ_C12-029_RSLP-20_Launch_Services.html
« Last Edit: 01/07/2015 01:12 PM by Jim »

Offline ugordan

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Re: The SpaceX Scrubs thread
« Reply #41 on: 01/07/2015 01:19 PM »
What I'm wondering is, in this particular abort, why was the hold called by the operator and not the vehicle software immediately. The statement George Diller (BTW, didn't he retire from launch commentary?) made at the time was that it would have caused an automatic abort anyway. So what's the point of deferring that decision if the slew check was done somewhere around T-4:30 ?

It's as if there's another check done later, specifically for the drift as opposed to just being able to cover the entire test slew envelope (one not necessarily excluding the other)?
« Last Edit: 01/07/2015 01:25 PM by ugordan »

Online Lar

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Re: The SpaceX Scrubs thread
« Reply #42 on: 01/07/2015 01:59 PM »
This thread is not without merit.... But when I start seeing scrubs of hot fires, then I think it has gone too far.

The same goes for delays months in advance which shifts the launch date.

How about limiting it to scrubs/delays of actual launch attempts, only within a few days of the first launch attempt? In other words, any delay or scrub AFTER the hot fire.

I think there's merit in tracking everything if the data is available.  Those who want to can filter out the scrubs leading up to hot fire...  My concern would rather be that we might be building a false picture of reliability trends, if the data for some flights is more complete than others. Especially so if the earlier data is more incomplete... that will look like things are more troublesome today than earlier (or at least not improving as fast), which would be a very false picture if in fact the trend is the other way.

I commend Cartman for taking this on.
« Last Edit: 01/07/2015 02:02 PM by Lar »
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Offline S.Paulissen

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Re: The SpaceX Scrubs thread
« Reply #43 on: 01/07/2015 02:00 PM »
Because, like people, software isn't perfect.  Better to have redundant systems.
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Offline Brovane

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Re: The SpaceX Scrubs thread
« Reply #44 on: 01/07/2015 02:07 PM »
I had one person telling me on another board because a SpaceX mission was originally proposed to lift off in February but was re-scheduled to a later date in the year for (whatever reason) that means the mission was late. 

http://www.nasa.gov/home/hqnews/2012/jul/HQ_C12-029_RSLP-20_Launch_Services.html

Thanks Jim for that link.  That is a great example.  Obviously this mission didn't lift off in December 2014.  It is slated for lift off the end of March 2015 currently from VAFB.  Lets assume that in March Jason-3 lift's off and there are no scrubs, issues with static fire etc.  Do we call that a on-time launch?  The launch itself is several months late from when it was originally procured. 
"Look at that! If anybody ever said, "you'll be sitting in a spacecraft naked with a 134-pound backpack on your knees charging it", I'd have said "Aw, get serious". - John Young - Apollo-16

Online symbios

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Re: The SpaceX Scrubs thread
« Reply #45 on: 01/07/2015 02:40 PM »
I assumed that we where interested in the technical reliability/progress of the Falcon LV not the ability of SpaceX to keep to scheduled or the availability of the cargo.

I would say that any schedule change that is done in advance of a launch and is not related to any technical problems to that specific launches LV should not be addressed.
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Offline Jim

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Re: The SpaceX Scrubs thread
« Reply #46 on: 01/07/2015 02:56 PM »


Thanks Jim for that link.  That is a great example.  Obviously this mission didn't lift off in December 2014.  It is slated for lift off the end of March 2015 currently from VAFB.  Lets assume that in March Jason-3 lift's off and there are no scrubs, issues with static fire etc.  Do we call that a on-time launch?  The launch itself is several months late from when it was originally procured. 

It is now June.

Offline cscott

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Re: The SpaceX Scrubs thread
« Reply #47 on: 01/07/2015 03:11 PM »
What I'm wondering is, in this particular abort, why was the hold called by the operator and not the vehicle software immediately. The statement George Diller (BTW, didn't he retire from launch commentary?) made at the time was that it would have caused an automatic abort anyway. So what's the point of deferring that decision if the slew check was done somewhere around T-4:30 ?

It's as if there's another check done later, specifically for the drift as opposed to just being able to cover the entire test slew envelope (one not necessarily excluding the other)?

As I understand it, the null offset for the Z TVC actuator was drifting.  The rate of drift was such that it would eventually hit the software limit and trigger an automatic abort.  But the operator on console (a) could see that it had begun to drift, and (b) was watching specifically for such a thing because this had been a problem in an earlier static fire (I don't remember if it was the first or second).  They thought they had fixed the problem.  Any drift at all meant that they hadn't actually gotten to the root cause, and so they did a manual hold out of an abundance of caution.  Something unexpected was going on.

*Probably* the drift would have reached the limit and triggered the automatic abort.  But what if it didn't?  What if the drift stabilized just short of the limit and held there long enough to allow the launch?

The launch director called the manual hold because even if that had happened, he still wanted to take a long close look at that actuator before the rocket was allowed to leave the pad.  No mystery.

Offline Brovane

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Re: The SpaceX Scrubs thread
« Reply #48 on: 01/07/2015 03:38 PM »


Thanks Jim for that link.  That is a great example.  Obviously this mission didn't lift off in December 2014.  It is slated for lift off the end of March 2015 currently from VAFB.  Lets assume that in March Jason-3 lift's off and there are no scrubs, issues with static fire etc.  Do we call that a on-time launch?  The launch itself is several months late from when it was originally procured. 

It is now June.

Is that SpaceX requesting the change in date or NASA? 
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Offline nimbostratus

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Re: The SpaceX Scrubs thread
« Reply #49 on: 01/07/2015 03:40 PM »
I get no specific infornation, but there is a simple reason, engines optimized for vacuum have problems with firing at sea level.
And how the thrust vectoring problem was detected for this attempt is a mystery.

They slew the engine during the countdown

No mystery if they power on the second stage engine for the status check.
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Offline Jim

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Re: The SpaceX Scrubs thread
« Reply #50 on: 01/07/2015 03:48 PM »

No mystery if they power on the second stage engine for the status check.

The stage is powered because it is minutes from launch, it has propellants loaded and it is controlling the whole vehicle.

Offline cartman

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Re: The SpaceX Scrubs thread
« Reply #51 on: 01/07/2015 03:52 PM »
Hi everybody,
I am now trying to get info from the update threads one mission at a time, starting from CRS-5 and working backwards. When i think i have gathered everything i can find, i will mark it as --request for verification-- and post it here as a single post, so that people can verify it. Here is the CRS-5 mission:

Falcon 9 Flight 14 - SpaceX CRS-5 (request for verification)
  S) 2014-12-17, Early engine shutdown during static fire [1]
  D) 2014-12-19 - 2015-01-05, Delay due to static fire issue, ISS beta angles and holidays [1]
  F) 2014-12-19, Successful static fire [1]
  C) 2015-01-05, Z axis actuator drift on the 2nd stage thrust vector control system, Τ-1:21 [2]


[1] http://www.nasaspaceflight.com/2014/12/spacex-static-fire-falcon-9-crs-5/
[2] http://www.nasaspaceflight.com/2015/01/spacex-dragon-crs-5-launch-historic-core-return/
« Last Edit: 01/07/2015 04:27 PM by cartman »

Offline eric_astro

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Re: The SpaceX Scrubs thread
« Reply #52 on: 01/07/2015 03:55 PM »
What follows does not include weather scrubs. Only scrubs for technical issues. Also, IMHO... and I am a fan boy not a rocket scientist.

My background is software and I've learned that you never get the last bug out of complex systems. There was an academic effort to devise methods to prove programs correct. It fizzled. Any large complex software package always has bugs, IMHO. You fix them as you find them and your goal is to introduce less new bugs than you fix. Over time older code gets more and more robust (but since the large complex software package is having new features bolted on, it may or may not be getting buggier overall)

I'm not bothered by scrubs, per se.

What would bother me is if the scrubs were due to the same exact problem over and over.

My expectation is that over time, the scrubs/launch ratio will decline, and that the nature of the problems that caused scrubs would become more and more esoteric and  more and more edge case related.

Scrubs better than LOV.

IIRC, the shuttle software was deemed pretty well free of bugs (after an almost unbelievable number of man-hours!).

Offline cscott

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Re: The SpaceX Scrubs thread
« Reply #53 on: 01/07/2015 03:56 PM »
@cartman -- I'm assuming you're deliberately not including the delay from early December (12/7 I think) caused by cargo reshuffle after the Orbital incident?

Offline cartman

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Re: The SpaceX Scrubs thread
« Reply #54 on: 01/07/2015 03:58 PM »
@cartman -- I'm assuming you're deliberately not including the delay from early December (12/7 I think) caused by cargo reshuffle after the Orbital incident?
Yes, I am looking only for issues with the rocket.

Offline cartman

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Re: The SpaceX Scrubs thread
« Reply #55 on: 01/07/2015 04:26 PM »
[Falcon 9 Flight 12 - Asiasat 6 (not verified)
  F) 2014-08-22, Successful static fire [10]
  D) 2014-08-27 - 2014-09-06, Delay due to F9R accident, commonality evaluation [11]
  L) 2014-09-07, Successful launch [12]
Falcon 9 Flight 13 - SpaceX CRS-4 (not verified)
  F) 2014-09-17, Successful static fire [8]
  C) 2014-09-19, Weather scrub [9]
  L) 2014-09-21, Successful launch [9]


[8] http://www.nasaspaceflight.com/2014/09/falcon-9-v1-1-static-fire-crs-4-launch/
[9] http://www.nasaspaceflight.com/2014/09/spacex-launch-dragon-crs-4-mission/
[10] http://www.nasaspaceflight.com/2014/08/spacex-static-fire-asiasat-6-test-failure/
[11] http://www.nasaspaceflight.com/2014/08/spacex-delay-asiasat-6-launch/
[12] http://www.nasaspaceflight.com/2014/09/spacex-falcon-9-asiasat-6-mission/
« Last Edit: 01/07/2015 04:54 PM by cartman »

Offline saliva_sweet

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Re: The SpaceX Scrubs thread
« Reply #56 on: 01/07/2015 06:49 PM »
I have been compiling data on F9 1.1 announced launch dates and delays for some time. I'll attach my spreadsheet, maybe it's of use. The format is somewhat messy unfortunately. I also attach a graph I made based on these data. Take the comparison with Atlas V with agrain of salt though, because It only uses data from the 3 most recent and two upcoming AV launches.

Offline cartman

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Re: The SpaceX Scrubs thread
« Reply #57 on: 01/07/2015 10:32 PM »
Thanks for your spreadsheet, its very useful and I already found a few things i needed.

I guess this is where SpaceX must make the most progress this year, trying to get a good chunk off that large manifest...


Falcon 9 Flight 11 - Asiasat 8 (not verified)
  F) 2014-07-31, Successful static fire [13]
  C) 2014-08-06, Abort, 1st stage hydraulic parameters T-0:45 [14]
  L) 2014-08-06, Successful launch [14]

[13] http://www.nasaspaceflight.com/2014/07/falcon-9-static-fire-test-ahead-asiasat-8-mission/
[14] http://www.nasaspaceflight.com/2014/08/spacex-falcon-9-v1-1-asiasat-8-launch/
« Last Edit: 01/07/2015 10:44 PM by cartman »

Offline cartman

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Re: The SpaceX Scrubs thread
« Reply #58 on: 01/07/2015 11:21 PM »
The cursed OG2 mission. 6 NSF articles about it!

Falcon 9 Flight 10 - OG2 Mission 1 (not verified)
  S) 2014-05-08, Umbilical connections between the pad and the rocket [15]
  S) 2014-05-09, Helium leak at Composite Overwrap Pressure Vessels (COPV) [16]
  D) 2014-05-10 - 2015-06-20, Delay due to helium leak, range, re-test on the satellites [16,17]
  F) 2014-06-13, Successful static fire [18]
  C) 2014-06-20, Pressure decrease in 2nd stage [19]
  C) 2014-06-21, Weather (the one without the webcast) [19]
  C) 2014-06-22, 1st stage TVC actuator [19]
  D) 2014-06-22 - 2015-07-14, Delay due to TVC actuator, range maintenance [19]
  F) 2014-07-11, 2nd Successful static fire [19]
  C) 2014-07-14, Ground Support Equipment (GSE) [20]
  L) 2014-07-14, Successful launch [20]

[15] http://www.nasaspaceflight.com/2014/05/spacex-falcon-9-static-fire-test/
[16] http://www.nasaspaceflight.com/2014/05/spacex-targets-june-11-falcon-9-orbcomm/
[17] http://www.nasaspaceflight.com/2014/06/commercial-duo-refine-upcoming-launch-dates/
[18] http://www.nasaspaceflight.com/2014/06/spacex-completes-falcon-9-static-fire-delays-launch/
[19] http://www.nasaspaceflight.com/2014/07/spacex-conducts-static-fire-next-falcon-9/
[20] http://www.nasaspaceflight.com/2014/07/spacex-falcon-9-v1-1-orbcomm-og2-mission/
« Last Edit: 01/07/2015 11:22 PM by cartman »

Offline deruch

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Re: The SpaceX Scrubs thread
« Reply #59 on: 01/08/2015 03:00 AM »
Great thread!  Can I request that weather delays/scrubs be a different color than red (i.e. different from technical issue scrubs).  Maybe blue?  I'm fine with them being listed, but the whole point of this thread is really about tracking SpaceX overcoming the technical bugs of developing a reliable launch system.  So having an easy way to visually ignore weather scrubs is, IMHO, reasonable.
Shouldn't reality posts be in "Advanced concepts"?  --Nomadd

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