Falcon 1 & Falcon 9

SpaceNut · 2007-03-21 06:27:17

Ah, the answer that defines failure for Nasa is Manned flight and if one had been onboard then there would have been all kinds of bad publicity.

Goes to show that alot more than one would think is in the testing programs to certify the pieces for use.

It is good that Spacex was able to not only abort a launch on the pad but that they tried after resolving the issue so quickly. Also good was a complete first stage flight, I am sure no more sub standard parts...

noosfractal · 2007-03-21 06:33:08

http://spacex.com/updates.php

Elon Musk says ...

...
We retired almost all of the significant development risk items, in particular:

- 1st stage ascent past max dynamic pressure

- avionics operation in vacuum and under radiation

- stage separation

- 2nd stage ignition

- fairing separation

- 2nd stage nozzle/chamber at steady state temp in vacuum

Falcon flew far beyond the "edge" of space, typically thought of as around 60 miles. Our altitude was approximately 200 miles, which is just 50 miles below the International Space Station. The second stage didn't achieve full orbital velocity, due to a roll excitation late in the burn, but that should be a comparatively easy fix once we examine the flight data. Since it is impossible to ground test the second stage under the same conditions it would see in spaceflight, this anomaly was also something that would have been very hard to determine without a test launch.

All in all, this test has flight proven 95+ percent of the Falcon 1 systems, which bodes really well for our upcoming flights of Falcon 1 and Falcon 9, which uses similar hardware. We do not expect any significant delay in the upcoming flights at this point. The Dept of Defense satellite launch is currently scheduled for late Summer and the Malaysian satellite for the Fall.
...

GCNRevenger · 2007-03-21 06:34:05

Looks like building an LV is a but harder than the AltSpacers' thought... big surprise I know. "Oh it'll be easy" ...not!

We feel that is something straightforward to fix

On what planet? certainly not this one. Your repeatedly and very long delayed rocket, heralded with much fanfare on the National Mall four years ago, which is supposed to be simpler than its competitors and packed-to-the-rivets with fault-sensing electronics failed again.

And this time, instead of last time when you got lucky and had video footage that pointed to the faulty system, you've got nothing but hunches from pad experience. After all, it lost telemetry and the second stage was destroyed during suborbital reentry. I can't see how this will be "straightforward" to fix if you don't know what happened like last time. And it certainly wasn't a good day, modern LVs need reliability around 95-98% to be credible for launching satellites, and this is another opportunity lost to start building Falcon-I's reputation.

When's the next shot? 2011?

noosfractal · 2007-03-21 06:50:02

http://spacex.com/video_gallery.php

You can see the "roll excitation" in the last 30 seconds of the "Falcon 1 DemoFlight 2 Launch" video.

RedStreak · 2007-03-21 12:05:50

"Oh it'll be easy" ...not!
We feel that is something straightforward to fix
On what planet? certainly not this one. Your repeatedly and very long delayed rocket, heralded with much fanfare on the National Mall four years ago, which is supposed to be simpler than its competitors and packed-to-the-rivets with fault-sensing electronics failed again.
When's the next shot? 2011?

Dang you know how to burn GCN :twisted:

Suffice to say they better get their act together on launch 3...their Space Dragon module is rapidly running out of steam for its fire at this rate.

Marsman · 2007-03-21 17:50:04

I'm not sure what some people have against new private space groups like SpaceX but I would like to know. Is is that they hype themselves up to be more than they are? If so maybe you need to step back and understand the business side a bit better. Until recently all we had was large government contractors like Lockheed/Boeing etc. Now we have a new group of companies making claims that they can reduce the cost of LV's. In the business world that would be seen as a threat. If my competitor is going to bring out a product much cheaper than me, then action must be taken to stay competitive.

Living up to such claims is another matter though, as we can all see. Rocket science is not easy as they are finding out. But marketing their brand is a part of normal business strategy. I mean how many products and services advertise themselves to be more than what they are yet most of us don't worry about it? From a business perspective marketing is just as important as having a product that works right. Especially when trying to break into a market dominated by a few large government contractors. The reason I admire SpaceX is that they at least are trying to live up to their claims. Last launch was lost after 29 seconds, this one was an order of magnitude better, anyone with sense could see that. In the effort to create lower cost LV's I expected failures because I understand the nature of how complex any LV is. Plus you need to remember that Elon Musk has funded most of this out of his own pocket. As far as I can see there is no other game in town for new private launchers so lets cut them some slack. They are venturing into uncharted territory by trying to produce a low cost launch vehicle so let's give them some room to make mistakes and learn. Being a private business they don't have much room to move so their next launch will have to be perfect, we all know this. Beyond all this though, the effort by any company to try and reduce launch vehicle costs is to be admired, and I wouldn't care if it was Lockheed or anyone else. Or would you prefer that space remain the domain of large government agencies and a few select astronauts?

Grypd · 2007-03-22 05:57:18

Spacedaily did an analysis of the video and they are considering it to have been a collision with the first and second stage that could have damaged the upper stage so causing the failure.

Falcon 1 Video Suggests Stage Collision

I know a lot of ifs and buts here. Then again all we have is eyes not the sensor information that SpaceX has.

Onboard video of the orbital launch strongly suggests, however, that there was a collision between the top of the first stage and the exit cone on the second stage at staging. Less than 15 seconds after staging, a structural ring near the bottom of the cone can be seen disintegrating, possibly as a result of the collision.
It is not known what, if any, effect a collision and the ring disintegration might have had on the vehicle, which failed to reach orbit after what SpaceX has described as a roll control problem. A control issue is evident as a conical oscillation of increasing severity towards the end of the released video, although it appears mostly to involve pitch and yaw, with the roll position holding relatively steady

noosfractal · 2007-03-22 17:14:57

http://www.spaceflightnow.com/falcon/f2/status.html

Elon Musk says ...

Question: What was the debris seen floating away from the second stage engine?

"What you might have seen was basically titanium half-hoops that are used to stabilize the nozzle on ascent. However, once you get to a certain temperature the bonding agent for those titanium rings comes off and the titanium rings float away, which occurred as expected."

C M Edwards · 2007-03-23 12:41:49

There was clearly contact between the first stage and the second stage engine bell, with the second stage nozzle being nudged to one side. And the video does not show any loss of roll control - the end shows what appears to be the beginnings of a spin, but it's all pitch and yaw ("Coning"). SpaceX's denial lacks credibility on those points. However, it's also equally clear that the engine ignites as expected and the vehicle recovers after separation, suggesting that there was no irrecoverable damage to the gimbal. The impact wasn't enough to knock those titanium spacers off, either, in spite of the fact that they appear to stick out about a couple of centimeters from the outer edge of the nozzle.

The trouble appears to set in at about the time the nozzle is starting to glow good and red. At that kind of temperature, thermal expansion would create stresses in the engine just as great as or greater than anything it would have seen being brushed by the first stage. Damage could have occured while the nozzle was being pushed around, but it did not cause the conveniently immediate failure that we would need to make a diagnosis based solely on this video. There was no visible breakage, leakage or outgasing, and the engine functioned for a minute and a half with no sign of trouble.

This collision was minor and incidental. I think the problem lies elsewhere.

Too bad: a few extra spacers would have been a quick and simple fix.

Grypd · 2007-03-23 13:39:43

Elon confirms that there was a collision between the first and second stages and that the first stage was not recovered.

SpaceX Confirms Stage Bump On Demoflight 2

"Yes, the stage sep bump will obviously need to be addressed, however it does not appear to have caused damage," Musk said. "The reason we chose a niobium metal skirt is that it is resilient to bumps vs C-C [carbon-carbon composite] nozzle, which is brittle and may crack."
According to the SpaceX website, "An impact from orbital debris or during stage separation would simply dent the metal, but have no meaningful effect on engine performance." Musk himself asserted that "There is substantial inflation pressure on the nozzle, so, even if the skirt dented, it would undent immediately after ignition."

So what did cause the failure.

Musk said that SpaceX would publish a detailed update on the launch on its website by next week, noting it was "so very important that we have time to properly digest the data."

We will have to wait till then I suppose.

C M Edwards · 2007-03-23 15:57:05

Regarding the second stage Kestrel engine, Musk said "The surprise was how cool the nozzle ended up being. It is capable of glowing white hot and was only a little bit red in places. We clearly have far more film cooling than is actually needed."

Um, yes, that's referred to as "Safety Factor", Elon.

I think they had better figure out why it's falling apart before they start whacking away at the parts that actually work.

C M Edwards · 2007-03-23 17:17:47

We feel that is something straightforward to fix
On what planet? certainly not this one. Your repeatedly and very long delayed rocket, heralded with much fanfare on the National Mall four years ago, which is supposed to be simpler than its competitors and packed-to-the-rivets with fault-sensing electronics failed again.

Musk made the claim a year or so ago that SpaceX expected failures and had sensibly budgeted for several of them. I suspect that SpaceX is right where its investors expect it to be as far as destructive testing. Projecting based on the previous two attempts, I estimate they'll be ready to fly again in 8 to 12 months - which, BTW, is surprisingly rapid turnover for a construction project of comparable complexity, and has been twice demonstrated by SpaceX.

Unless Musk comes out and says they're going to fold, I see no reason to expect SpaceX to abandon their test plan before the next flight.

As for whether or not the fix to one particular problem is simple, who is to say? For example, they got the camera to work right this time. Who knows what might work next time.

Overall system reliability of the Falcon prototype is not looking good at this point, but we're looking at a series of successively refined prototypes. Observed performance of this system should still be varying on a curve at this point. What we saw is what we should expect to see in this type of testing program - still failure, but failing after progressively better and better performance. And it's what SpaceX has said they expect for the past four years. The real death knoll of SpaceX will be to have precisely the same thing go wrong twice, with no corresponding improvement in performance.

SpaceNut · 2007-03-23 20:17:25

Sounds like a good run down C M Edwards on the video, I have not seen it as of yet.. I've got dial up so it takes a while... will try later.

Hummm raming seperation reverse thrusters not firing hard enough to allow first stage to slow down or second stage took to long to fire...

It does sound like they are on their way thou and better luck with flight number 3 for alot more does ride on that flight than does a demonstrator flight since it will carry a real payload.

John Creighton · 2007-03-23 23:50:00

Overall system reliability of the Falcon prototype is not looking good at this point, but we're looking at a series of successively refined prototypes. Observed performance of this system should still be varying on a curve at this point. What we saw is what we should expect to see in this type of testing program - still failure, but failing after progressively better and better performance. And it's what SpaceX has said they expect for the past four years. The real death knoll of SpaceX will be to have precisely the same thing go wrong twice, with no corresponding improvement in performance.

What kind of reliability do you think we can expect for the final product?

John Creighton · 2007-03-24 01:09:26

I just watched the videos and I am more optimistic now then I was before the launch. Granted they still have a bit to go but I am crossing my fingers.

ftlwright · 2007-03-24 01:27:24

There are a few scenarios which can adequately explain the 'coning' that was witnessed before the feed was terminated. First, it is possible that the lateral movement was initiated by stage separation. This is fairly normal; the Atlas V typically experiences 3+ g-loading during staging events. This may indicate that the ACS system was not robust enough to compensate for the forcing modes (the rocket did seem to hit an oscillational mode towards the end) extinguishing its ACS fuel early in the stage event. This could easily be the result of a poorly designed feedback loop in the guidance/navigation control. This was my initial thought before seeing the video and it still may have played a part in its failure.

The next explanation is that the second stage was experiencing fuel sloshing, which is fixable with baffles installed in the fuel tank. This is a rather simple issue, though it would be considered amateurish if it was missed.

Ultimately, it was a failure of a systems analysis of the rocket with no single subsystem being the culprit. The reliability of the Falcon I will be abysmal until an adequate systems analysis is done, even then it would be average at best.

Don't get me wrong, I would really like to see SpaceX succeed, and the guys working on the project are getting a rare opportunity to get their hands dirty with rocket design (a rarity in the industry today). My concern is that they still have a few key piece missing before they will have a reliable launch system on their hands. At least they're better off than most of these alt.spacers.

noosfractal · 2007-03-24 02:53:24

David M. Palmer @ sci.space.policy says ...

It was a fuel leak around the top of the main engine, which burned
through some helium pneumatic lines. The rocket was running straight
and true until t+29 when the helium tank pressure dropped enough that
the safety system terminated the flight.

C M Edwards · 2007-03-24 16:56:05

What kind of reliability do you think we can expect for the final product?

Your guess is as good as mine. There are limits to how much SpaceX can refine their existing design, but the fact that they're able to make it all the way to stage two ignition is encouraging.

GCNRevenger's statement of 95% to 98% is about right for the theoretical reliability necessary for a launch vehicle. I believe NASA's standard is 98% for unmanned vehicles. (I may be misremembering the number, but I recall reading that they do have a standard.) If SpaceX can't get to 95%, then it won't matter what their reliability is.

C M Edwards · 2007-03-24 17:07:30

David M. Palmer @ sci.space.policy says ...
It was a fuel leak around the top of the main engine, which burned
through some helium pneumatic lines. The rocket was running straight
and true until t+29 when the helium tank pressure dropped enough that
the safety system terminated the flight.

A slow loss of system pressure would create a gradually worsening loss of control, in which the stage could straighten up and fly right at first, even with a major upset like this collision, but later spin out of control under perfectly normal operating conditions. That sounds completely consistent with what's shown in the video clip that SpaceX released, except one thing:

Who is David Palmer that he'd have access to the necessary telemetry to confirm this? The video shows nothing one way or the other.

noosfractal · 2007-03-24 18:08:33

Who is David Palmer

I only know him as a poster of non-bullshit to usenet. Such people are incredibly rare, so they are easy to keep track of. He has a PhD from Caltech and spent a number of years at Goddard, so it is plausible for him to be in contact with one of the teams doing the actual analysis. Still just rumor though, obviously.

C M Edwards · 2007-03-25 06:45:17

Who is David Palmer
I only know him as a poster of non-bullshit to usenet. Such people are incredibly rare, so they are easy to keep track of. He has a PhD from Caltech and spent a number of years at Goddard, so it is plausible for him to be in contact with one of the teams doing the actual analysis. Still just rumor though, obviously.

Well, identifying the problem as a loss of pressurization event in the control mechanism is the most plausible explanation I've seen so far. I'm uncertain about the "fuel leak burning through some pneumatic lines" as a root cause, though. SpaceX's Kestrel is a kerosene fueled motor, so having the damage due to a fuel leak implies a source of ignition that is equally mysterious.

Soyuz · 2007-03-25 14:14:36

David M. Palmer @ sci.space.policy says ...
It was a fuel leak around the top of the main engine, which burned
through some helium pneumatic lines. The rocket was running straight
and true until t+29 when the helium tank pressure dropped enough that
the safety system terminated the flight.

You should check the date on that post. It will say 2006 not 2007. He's talking abour the first launch failure. The first stage completed it burn this time.

noosfractal · 2007-03-25 14:45:08

Oops, sorry. I'm an idiot.

noosfractal · 2007-03-27 16:01:47

http://www.nasaspaceflight.com/content/?cid=5056

(I double checked the date this time)

Elon Musk says ...

'In a nutshell, the data appears to show that the increasing oscillation of the second stage was due to the slosh frequency in the LOX tank coupling with the thrust vector control system,' added Musk.

'Our simulations prior to flight had led us to believe that the control system would be able to damp out slosh, however we had not accounted for the perturbations of an impact on the stage during separation, followed by a hard slew to get back on track.'

While the impact observed during separation failed to damage the second stage engine's nozzle, the cause is currently being blamed on the vehicle's rotation being fives times higher than the expected maximum.

...

we believe that the slosh issue can be dealt with easily by adding more baffles, particularly in the LOX tank. The Merlin shutdown transient can be addressed by initiating shutdown at a much lower G level, albeit at some risk to engine reusability.

ftlwright · 2007-03-27 22:39:15

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#251 2007-03-21 06:27:17

Re: Falcon 1 & Falcon 9

#252 2007-03-21 06:33:08

Re: Falcon 1 & Falcon 9

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Re: Falcon 1 & Falcon 9

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Re: Falcon 1 & Falcon 9

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Re: Falcon 1 & Falcon 9

#256 2007-03-21 17:50:04

Re: Falcon 1 & Falcon 9

#257 2007-03-22 05:57:18

Re: Falcon 1 & Falcon 9

#258 2007-03-22 17:14:57

Re: Falcon 1 & Falcon 9

#259 2007-03-23 12:41:49

Re: Falcon 1 & Falcon 9

#260 2007-03-23 13:39:43

Re: Falcon 1 & Falcon 9

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Re: Falcon 1 & Falcon 9

#262 2007-03-23 17:17:47

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#263 2007-03-23 20:17:25

Re: Falcon 1 & Falcon 9

#264 2007-03-23 23:50:00

Re: Falcon 1 & Falcon 9

#265 2007-03-24 01:09:26

Re: Falcon 1 & Falcon 9

#266 2007-03-24 01:27:24

Re: Falcon 1 & Falcon 9

#267 2007-03-24 02:53:24

Re: Falcon 1 & Falcon 9

#268 2007-03-24 16:56:05

Re: Falcon 1 & Falcon 9

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Re: Falcon 1 & Falcon 9

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Re: Falcon 1 & Falcon 9

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Re: Falcon 1 & Falcon 9

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Re: Falcon 1 & Falcon 9

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