SpaceX Falcon 9 v1.1 - Dragon - CRS-5/SpX-5 -Jan. 10, 2015 - DISCUSSION

[IanH84]

Perhaps there was some sort of problem with the second stage O2 tank? It looks like it was venting pretty heavily before they called the hold.

It was an actuator for thrust vectoring (hasn't this happened a few times in a row?)

Genuine question: How's this stuff only get found literally minutes before launch? Especially with such a long time since the previous launch...

My guess: the engine chill-down affects the actuators somehow.

Probably. Here's an article on actuator drift from a hydraulics and pneumatics trade publication that explains drift and how to compensate for it http://hydraulicspneumatics.com/other-technologies/truth-about-problem-valves

Temperature and pressure changes can induce null drift, which moves the zero point of the actuator and requires either trim adjustment or control input to hold it there. I don't know the actual numbers for F9, but let's say that gimbal range is half of the actuator's range and there's a safety factor of 2; if null drift starts happening at a rate that will put it more than 25% from the set zero point by the end of second stage operation, it's not safe to launch

[Ben the Space Brit]

I know that sometimes countdowns can be days long. I'm wondering - Was this mission actually in its countdown when the scrub call was made, or was it a decision not to commence the countdown?

[whitelancer64]

I know that sometimes countdowns can be days long. I'm wondering - Was this mission actually in its countdown when the scrub call was made, or was it a decision not to commence the countdown?

The hold was called at 1:28 before launch, countdown was halted at 1:22 and because the launch window was instantaneous, the launch was scrubbed.

[garidan]

Perhaps there was some sort of problem with the second stage O2 tank? It looks like it was venting pretty heavily before they called the hold.

It was an actuator for thrust vectoring (hasn't this happened a few times in a row?)

Genuine question: How's this stuff only get found literally minutes before launch? Especially with such a long time since the previous launch...

My guess: the engine chill-down affects the actuators somehow.

If the engine chill-down affects the actuators , this is a design problem, to solve for the next flights. I as a "newby" don't "accept" a scrub for this after weeks of checks and almost 2 hot fire tests.
If they want to lower costs of space rocket launches, they have to aim to fewer scrubs.
It seems too "fragile" as a whole ...

[mvpel]

Did anyone catch if they did an "MVAC TVC wiggle" around the T-4:30 mark as I recall from a previous launch? My Livestream client was flaky and I missed the period where that would have been done.

[Mapperuo]

Did anyone catch if they did an "MVAC TVC wiggle" around the T-4:30 mark as I recall from a previous launch? My Livestream client was flaky and I missed the period where that would have been done.

Can be heard at 04:36 'Starting MVAC TVC Motion'.

[Herb Schaltegger]

If the engine chill-down affects the actuators , this is a design problem, to solve for the next flights.

Maybe. Maybe it's not a "design problem," perhaps it's a defective actuator. Perhaps it's out-of-spec insulation. Perhaps there was a manufacturing issue. Perhaps there was an environmental issue involving the ambient conditions of the pad today. Maybe there was a sensor or software calibration issue. Et cetera, ad nauseum, ad tedium ...

I as a "newby" don't "accept" a scrub for this after weeks of checks and almost 2 hot fire tests.

As a newbie, you ought to consider there are plenty of things you may not understand about spaceflight engineering technology.

[Antares]

If the engine chill-down affects the actuators , this is a design problem, to solve for the next flights. I as a "newby" don't "accept" a scrub for this after weeks of checks and almost 2 hot fire tests.
If they want to lower costs of space rocket launches, they have to aim to fewer scrubs.
It seems too "fragile" as a whole ...

Most likely it falls in the realm of "Quality" - repeatably applying the process (which Elon says he hates) to get things right the first time.  It would be interesting to hear Elon elucidate his method of Quality without being process-oriented.  Such a method would be, in mundane ways that don't make media splashes, as groundbreaking as reusability.

[Pete]

I as a "newby" don't "accept" a scrub for this after weeks of checks and almost 2 hot fire tests.
If they want to lower costs of space rocket launches, they have to aim to fewer scrubs.

I as a "grammar nazi" don't accept such atrocious grammar after years and years of schooling. If you want to garner respect on this forum, you have to aim to fewer flubs.


There, see how easy it is to spout hollow criticism?
You need to accept that, despite all advances made so far, it is *still* rocket science that these guys are doing. Launching a vehicle to orbit is *hard*. Doing so cheaper than the going rate is *even harder*.
Launching at the rate they already are, for such a new enterprise, is unheard of in rocketry history.
(without mega-funding and many, many booms along the way)
.
And of top of all that, they have this silly/inspired/glorious dream of actually landing their first stage in one piece!

Patience. Sit back, and admire what they are already achieving, instead of gnashing at the stumbles they discover along the way.

[rower2000]

If the engine chill-down affects the actuators , this is a design problem, to solve for the next flights. I as a "newby" don't "accept" a scrub for this after weeks of checks and almost 2 hot fire tests.

So as a newbie you'd rather blow up the rocket than accept a scrub? Even to me as a non-rocket scientist (and another newbie on the forum) it's clear that a launcher is a very complex piece of machinery, and technology can break. Also at times that may seem unacceptable to a newbie.

And after all it's not THAT bad - they seem to average on 2.15 launch attempts per mission, assuming CRS-5 will launch on Friday on its 3rd attempt. And that is inflated by the SES-8 mission where Pad needed 6 attempts to get it off the ground - without that mission the average would be 1.83 attempts per mission. (DISCLAIMER: I did not count delays within a launch window as attempt and the data is what I found on the net, so the number of attempts might be incorrect. I counted 28 attempts for 13 missions for the F-9, v 1.0 and 1.1.)

[rpapo]

And after all it's not THAT bad - they seem to average on 2.15 launch attempts per mission, assuming CRS-5 will launch on Friday on its 3rd attempt. And that is inflated by the SES-8 mission where Pad needed 6 attempts to get it off the ground - without that mission the average would be 1.83 attempts per mission. (DISCLAIMER: I did not count delays within a launch window as attempt and the data is what I found on the net, so the number of attempts might be incorrect. I counted 28 attempts for 13 missions for the F-9, v 1.0 and 1.1.)

And much more to the point, they haven't lost a Falcon 9 on a working mission yet.  Their caution has paid off.

[rower2000]

And much more to the point, they haven't lost a Falcon 9 on a working mission yet.  Their caution has paid off.

Indeed they haven't. And I hope it stays that way.

[OxCartMark]

As I was watching the video live I noticed that there was (to my eyes at least) an image of a man painted on the side of the thing.  A man with a hat on and a microphone in front of his mouth.  Placement was just below and to the right of the American flag, which is below "Falcon 9".   Did I see that right?  What's that all about?  Have there been other images on Falcon 9s?  It can be seen at (approximately, from recollection) count times of 4:30 and 3:00.  Here is a screen grab from the Youtube replay that someone posted.  I think the resolution of this is less than what I originally saw and the control bar at the bottom may be eating into some of the image thus I've grabbed it too so as to not leave any of the image of the man out.

Goofball theories:
- Dedicated to or celebrating someone, similar to a Google Doodle
- Something that they are only willing to show partially now but which will make sense when shown returning to port on a barge if that comes to pass.

Mark

[VulcanCafe]

As I was watching the video live I noticed that there was (to my eyes at least) an image of a man painted on the side of the thing.  A man with a hat on and a microphone in front of his mouth.  Placement was just below and to the right of the American flag, which is below "Falcon 9".   Did I see that right?  What's that all about?  Have there been other images on Falcon 9s?  It can be seen at (approximately, from recollection) count times of 4:30 and 3:00.  Here is a screen grab from the Youtube replay that someone posted.  I think the resolution of this is less than what I originally saw and the control bar at the bottom may be eating into some of the image thus I've grabbed it too so as to not leave any of the image of the man out.

Goofball theories:
- Dedicated to or celebrating someone, similar to a Google Doodle
- Something that they are only willing to show partially now but which will make sense when shown returning to port on a barge if that comes to pass.

Mark

It looks to me like that is the attachment point of the new grid fins...

[Brick_top]

It just seems one of the grid fins?

[cartman]

Its a grid fin

[OxCartMark]

Wow yes, its a grid fin.  Totally obvious once you point that out to me.  Can you see the little cartoonish man I was seeing?  Funny.

Edit: Even in the grainy image I posted you can see other grid fins to the right and left of the "image", so quite daffy of me to see what I thought I saw.  Canals on mars?  Man in the moon face?

Mark

[cartman]

Yes, I also saw that, thats why i searched for images of that area!
The phenomenon is called patternicity or http://en.wikipedia.org/wiki/Apophenia and it is the reason we see faces in clouds, Jesus on toasted bread etc. Our brain always tries to find known patterns in random data.

[Brovane]

How does the number of Falcon9 launch delays/scrubs compare to the early launch history of the Atlas-V and Delta-IV?

[Robotbeat]

SpaceX hasn't blown up a rocket since Falcon 1 flight 3; historically you're very lucky if your first 5 launches of a new launch vehicle succeed, and they've developed two of them since F1 and launched each over 5 times successfully. They're doing something right. Some of that is testing the crap out of their rockets, some of it is intense monitoring of different subsystems (this last part is nothing new, of course).

It will take 100s of launches to get all these little bugs out, and they'll still happen. Frankly, given how many things have to go right for a launch to work, I'm always pleasantly surprised when a launch DOES go off without a hitch. (I admit Atlas V has done it enough times that I feel significantly less nervous, although it, too, has its glitches.)

SpaceX is competing against two launch providers that have a nearly spotless record of late. ULA and Ariane. One launch failure would set them back significantly (since they've only done 13 F9 launches, only 8 v1.1), so a launch failure for SpaceX would be more damaging statistically than it would for their competitors which have a much longer track record. So SpaceX has to be incredibly conservative with this stuff. A scrub makes no difference long term, but even a single launch failure may (even though it's bound to happen eventually if you launch 100s of times), as we saw with Antares.