I'd be giving that effort a strong B+ as a demo.
They got to really prove out their hold-before-release system and show off quite a rapid abort recycle, then they had what seems to have been a 100% by the numbers launch and first stage flight. The 1st stage separation appears to have been ropey (to us total amateurs admittedly) but the 2nd stage lit bang on the money and appeared to be doing the job well until telemetry was lost. That's a good 7/10 anfd pretty damn good for a second attempt surely.

So they don't get the whole cookie just yet but they are a lot closer now than they were yesterday in my book.

Musk confirmed the "roll control anomaly" according to SFN.

This launch, while impressive, illustrates why launching things into orbit is both risky and expensive. SpaceX is going to have to fly a lot of rockets, and study a fair number of failures, before they figure out all of the little, almost unnoticeable things that will jump out from the shadows and destroy their equipment (and the equipment of their paying customers).

For example, if first stage recontact with the second stage occurred after sep, or if the fairing struck the second stage engine when it was let go, they'll have to revisit all of their simulations and modeling, and add systems to keep these things from happening again. Then they'll have to fly those systems and validate their effectiveness. All of this requires actual test flights -- you obviously can't just rely on your paper models or your computer simulations.

Each test flight is a few million $'s worth of rocket, and you *have* to spend that money to get the bugs out of the hardware, or else you'll lose customer payloads. And soon you won't have any customers. At that point, it doesn't matter how brilliant your designers are or how well funded you were -- you're going to go out of business.

As I said, the whole thing points to some very good reasons why getting into orbit is hard, and why it's expensive. By the time SpaceX spends all of the money needed to have a reliable fleet of boosters, the costs they'll have already incurred will have to be amortized through the price of their services. So, while they may still offer the cheapest way to orbit, it ain't gonna be all *that* cheap, and certainly far more expensive than current estimates...

-the other Doug

Or - from another perspective, from SFN

Musk says 90 percent of the Falcon 1 rocket's technical challenges were proven out with this launch. He doesn't foresee needing another test flight before launching the first operational mission in late summer carrying the U.S. military's TacSat 1 spacecraft.

I recorded the web feed of the launch, but it's a fairly large file, so I'm not sure how best to deliver it. I'll start by uploading it to Google video. If anyone has suggestions for sending the full-res file, I'm wide open to them.

I'd be interested in seeing the video if you figure out a way to pass it around. I had to leave for a business meeting 15 minutes before launch. I hope Doug got his mocha. I had a nice Cabernet.

How large is "fairly large?"

http://spacex.com/video_gallery.php

Seems pretty clear to me that the Stage 2 engine got smacked by Stage 1 and 12 seconds later part of it ripped away.

3:28/3:29 - Stage 2 bngine bell getting soundly rung as stage 1 separates
3:41 - Edge of the Stage 2 engine bell starting to look noticably ragged
3:49 - "Ring" detaches in 2 pieces

I'm having problems cutting stills from the video but the timings should make it simple to find for those curious.

The SpaceX site has an interesting comment on the Kestrel's Nozzle construction:

That was definitely a lot more than a dent. hmmh

Launch video on YouTube.

What would be the functional impact of losing this "ring" at the engine nozzle? It seems to me the big problem arose due to buildup of an oscillation around the spacecraft roll axis. A case of positive feedback perhaps where the engine gimbal control actually winds up feeding the oscillation further, or maybe the effect just grew stronger due to rapidly diminishing mass of the vehicle.
I don't believe this is a pogo oscillation because IIRC pogo is a longitudinal oscillation. Of course, it's difficult to judge from the video whether any pogo effect was present because the camera probably wouldn't pick it up.

That ring is supposed to detach remember - so I wouldn't factor that into it at all.

I hate to admit Jeff Bell called it right, but he was right
Falcon failed and the majority of the private sector is going no where fast. They can try and spin this whatever way they wish but if it was NASA, the word 'failure' or 'multi-million dollar disaster' would be all over the medias news headlines and rightly so
SpaceX lost their payload yet again

Falcon 1, The World's Lowest Cost Rocket to Orbit.......maybe the subject title needs amending.......

That vehicle didn't tick all the boxes, but I wouldn't call it a total failure. Bell's take on SpaceX is no more right today than it was yesterday. Yeah - Elon's putting a positive spin on things - but when you look at the price of that LV, a new start up with 1.5 launches to their name - I think that was a very good mission. Hell - if it takes another 2 launches to get it spot on - they will then be offering a cheap, rapid LV. No one said it would be easy. No one said it would work first time. Calling the entire program a failure is, at this stage, hideously premature.

Doug

Doug do you have a reference that shows that the ring detach is by design?

http://www.spaceflightnow.com/falcon/f2/07...fingquotes.html

Odd to rely upon a temperature sensitive bonding agent to control the release of a stiffening ring.

That sounds more like the description of a failure mode than a flight asset.

I wonder if they charge extra for bugs in the soup in the local canteen:)

What we saw in the video could be caused by a number of things, but nozzle erosion and burn-through is definitely one of them.

We could only see about 30% or so of the entire engine bell. A really small burn-through could have occurred on a part of the nozzle that wasn't immediately visible. And that could have imparted a rolling moment to the stage.

Of course, there are a lot of other things that could have happened. I suppose we'll have to wait and see what SpaceX says about their telemetry and the tale it tells.

-the other Doug

I've seen things like wiring break loose off Delta second stages as well and wouldn't really attribute that as an abnormal scenarios.

Word on the NSF forums is the first stage recontact might have kicked off the propellant sloshing and it started an oscillation that fed off the attitude control countermeasures (positive feedback, an ugly beast) and it just lost battle with it after a while. They are saying the 2nd stage nozzle most likely didn't receive any damage (it's apparently pretty rubber-like), but the nudge started an oscillation chain reaction. Or maybe it was simply a case of a closed-loop where guidance didn't account for positive feedback effects like this when small attitude changes are allowed to grow rapidly.

Dvandorn, the nozzle heating up is perfectly normal as it's a radiation cooled design, it's not ablative nor regenerative cooled. I suspect it ought to have become much brighter glowing if a burn-through was to happen. In any case, a burn through would probably manifest itself as a sudden kick of the engine bell in one direction and I don't see that from the video. All there is is a gradual increase in oscillations, nudging both the engine and the rest of the vehicle.

"The second test launch of Falcon 1 took place today at 6:10 pm California time. The launch was not perfect, but certainly pretty good. Given that the primary objectives were demonstrating responsive launch and gathering test data in advance of our first operational satellite launch later this year, the outcome was great. Operationally responsive (ie fast) launch has become an increasingly important national security objective, so demonstrating rapid loading of propellents and launch in less than an hour, as well as a rapid recycle following the first engine ignition are major accomplishments."

they're sort of right aren't they?

The glow on the Kestrel engine was very similar to the glow - in colour and texture, to that on a Delta II second stage - I didn't see anything there I would consider unusual, and indeed upper stage nozzles seem to be very flexible - certainly the Delta II upper stage engine wobbles around quite a lot.

Sloshing sounds like a very convincing scenario. Hopefully Elon will continue his applaudable record of reporting events quite regularly and honestly and we'll soon know what actually happened.

Doug

For a test flight, it was certainly not a complete failure. They demonstrated a lot of good things, and the test of the first stage seems to have been almost completely successful.

If this was an opreational launch, though, it would have been a complete failure, no matter how well the first stage worked. The paying customer would have had his/her expensive satellite dumped into the ocean. That's the real definition of success or failure -- did you deliver the package where the customer wanted it to go?

As tempting as SpaceX's pricing seems to be, I know that if I had a payload that I really needed to place into orbit, I would definitely wait until the Falcons started flying successfully before I spent any money on them. Then again, I wouldn't buy the first model year of, say, a fuel-cell-powered car or a car with a hydrogen engine, either. I'd wait to see how well they work and what the service and maintenance issues *really* are, not just what the salespeople want me to believe they are...

-the other Doug

Quite agree - but if I had a cheap mission that was cash limited to the point of launching on a cheap Falcon in Q1-08, or not launching at all...I'd go for the Falcon.

Doug

Doug - is there something you want to tell us about Q1-08? Are you planning a UMSF microsat or perhaps another shed in LEO?

I wish DougSat is still a pipe dream.

I vote for a sail-powered package to Titan. Sail doubles as aero-capture device/parachute on arrival.

Maybe we should all pitch in for a pongsat ad....

Imagine the UMSF logo up here!

The video I recorded is about 150 mb. It starts half an hour or so (out of 45 minutes total) before the second countdown, so it could probably be trimmed down quite a bit. It seems to be pretty much identical in quality to the high quality wmv on this page, so unless someone wants the full countdown, there's probably not much point in trying to get it out there.

I grabbed this point-of-impact image from the hi-res video

Oooh - that would be very, very cool.

Back to the topic in question. SpaceX explicitly say that the second stage engine nozzle\bell is designed to take a bit of impact debris at separation but that was quite a smack, maybe they designed it to deal with such events but it sure looks dodgy as hell to me.

Looks to me their biggest problem was attitude control. Engines performed well, which is great news. The staging sequence introduced some big attitude disturbance that was probably the culprint causing recontact with the first stage.

A big part of the second stage burn also exhibited wobbly attitude and the engine nozzle was jittering noticeably the whole time. Things started to get very rough at T+04:42 and obviously soon after the thrust vector control reached its maximum authority with the nozzle making rough circles. It managed to keep the heading pretty well, though. It's even possible the oscillations would have died down after a peak, but we'll never know.

At T+04:55 the vehicle started to roll and that's probably what lead to LOS and automatic engine shutdown. Whether the attitude drift and roll problems were linked is the big question, I understand roll control is maintained via cold helium gas jets and it was speculated there could have been a leak somewhere.
That still leaves the question why engine pitch/yaw gimbal was having such a hard time keeping the vehicle steady.

Well, they don't call it an 'Hourman' Missle. The fastest turn around is an always loaded motor. The US has a lot of those.

If the bouncy seperation did not cause the control anomally, they have at least two problems...three if you include a credibility problem (great outcome?).

As an outside observer I agree with their assesment. As for credibility, I'm not sure where you are getting that.

I agree with ugordan's observations re control system difficulties. Given the impact, I have to wonder if one of the nozzle position sensors was affected (perhaps knocked out of calibration?) Oscillating control commands are usually caused by insufficient position feedback or rate sensing if the system itself is malfunctioning. I assume that they used linear variable differential transformers (LVDTs) or something else with high reliability and hopefully redundant channels; if they used feedback potentiometers or rely on single sensors, that could be bad...

Another possibility is that the rate sensors for the second stage aren't located in exactly the right place on the vehicle, I guess, but this seems unlikely.

The fuel sloshing scenario sounds plausible as well, but I can't imagine that they wouldn't have baffles in the tanks to prevent this sort of thing. Unpredictable center of gravity shifts are hard to compensate for...

http://www.youtube.com/watch?v=NE4HkniM3Vc...ted&search=

This video on youtube goes a bit longer than the live webcast and the video posted on the SpaceX site.

The last frame shows a time of +5 min, 14 sec, compared with the 5:01 "official version"

The sequence shows the slow roll that is visible in the last few "official" seconds of video rapidly increases in speed, together with the probable start of a tumbling motion. When the video cuts off, the total roll is somewhere around 3/4 of a turn and the speed is rapidly increasing. The last oscillation of the nozzle seems to be almost violent (the oscillation amplitude steadily increases with time) and rather out of step with the previous oscillations.

In addition, something nobody's noted here or on the Nasaspaceflight.com forum (that I can see)

http://forum.nasaspaceflight.com/forums/forum-view.asp?fid=6

is that at T+4:44, there is a long recangular, square-ended piece of white debris (like a segment of a window blind) falls past the camera and is visible for a few frames. The oscillations of the engine and vehicle get stronger rapidly starting maybe 3 seconds after this event, and more debris, most looking perhaps like shredded insolation or irregular shed ice pieces fall past the camera, the overall abundance of visible debris generally increases in the last 30 seconds. Other pieces are not clearly identifiable as discrete objects like the "slat" at 4:44, but it's clear things are being shaken nearly to bits.

I would not be surprised if at or just after the end of the youtube video, the vehicle had a major structural failure, as suggested by the extra-violent irregular motion in the last 1/2 second of video.

Beyond all this post-mortem analysis, the fact remains that they had a test flight that was a mission failure, but achieved some 90% of "detailed test objectives". In that, it resembles the flights of Saturn 502 (Apollo 6, which made orbit but had multiple problems and failed S-IVB restart) or the Delta IV Heavy (which didn't make the proper orbit and dropped secondary payloads into atmosphere-intercepting orbits.)

They have made a major step toward orbit with a totally new vehicle and should be congratulated.

Bits of 'white', I've seen in LOADS of upper stage vids - usually bits of ice falling off when the engine gimbals. As with that shuttle mission a year or so ago, a piece of ice can really look like something else in Zero G. With the engine gimbaling so hard, it wouldn't be suprising to have ice getting rattled off the top of the stage toward the 'end' of the sequence I guess. As the situation evolved, the 'wobble' got worse, the engine gimbaling got worse in reponse (and of course, the two looped one another ) and as a results the stage was getting more of a battering around and thus more ice debris would be normal I would have thought.

Doug

And by the time that rectangular piece of white stuff fell off, the vehicle wasn't really gimbaling so hard to think something structurally important broke loose. I'm also going with the chunk of ice explanation in this case.

A linear piece wouldn't be unusual either - probably formed down the side of an exposed pipe and fell off when rattled hard enough.

Doug

And it strikes me that they have done their testing in front of a live studio audience - basically the whole world watching them succeed or fail! How often do we get access to onboard camera footage on other "test" flights in real time?

I also might add that this was also a test flight of SpaceX as an organization - how they are able to learn from past mistakes, mission ops, etc.

I, for one, welcome our new PayPal space masters!

That's right Blackened cajun style! Did we have live Rocketcam feed from that launch?

But I actually meant to say what ugordon did say.

Very nice - I can never get enough of onboard video.

And thanks for the correction - I am afraid my lack of launcher knowledge is being exposed.

So, just why did SpaceX cut the feed? Clearly the rocketcam transmission continued -as has now appeared on YouTube. What purpose was served by abruptly cutting the feed to the internet?

Clearly SpaceX can do what they like with their video, after all it's their property and we are all incredibly grateful for their openness in sharing this experience with us.

It is just that this behaviour seems a little inconsistent.

Puzzled...

Rob

Was there still video feed after loss of telemetry
or were they both lost at the same time?

Jim - Ugordan... if you're going to have a bitch fight - do it elsewhere.

7 posts deleted.


Doug

Interview with Elon Musk on
http://www.nasaspaceflight.com/
Good news. They have recovered telemetry (and more video....I wanna see it but gimme a motion sickness pill first!) from some 2+ more minutes of flight. The vehicle shut down only about 1 min early at about 7.5m min into flight AND deployed the dummy payload mass.

And the problem was indeed coupling between the slosh in the LOx tank and the thrust vector control system. Slosh was apparently started by the collision with the first stage (triggered by larger than test-stand indicated tip-off forces from the first stage engine shutdown), AND the hard slew to get back on track. "....shutdown transient had a very high pitchover force. causing five times the max expected rotation rate."

And regarding the debris events.. Since the vehicle wasn't approaching breakup, I'd have to concur that the debris was mostly or all ice. The regularity of the rectangular piece is still odd, but I have no real idea of it's size and the "ice off a pipe" speculation seems plausible.

...well, I'll be. Definitely a plausible failure mode, but I still have to ask whether the second stage had internal baffles to prevent abrupt fuel COG shifts...makes me wonder if these were dropped in the name of mass savings.

Falcon engineers baffled by sloshing fuel...and aluminum nuts.

There were fuel sloshing problems during the early Mercury program, too.

They flew live-broadcast TV cameras inside Saturn and other launch vehicle tanks, with bright lights an everything (Mommy, it's dark in here!) to study fuel/oxidizer dynamics. One entire Saturn 1B flight (Saturn 202?) didn't have a CSM on top, the mission was just to study SIV-B behavior, I think. A Saturn 1 or early Centaur failed engine restart because they were unable to settle propellant adequately in the tank with ullage burn (or surface-tension control baffling). Some ?other? vehicle ended up in a flat spin, I think, with liquids ending up at opposite ends of fuel and oxidizer tanks, I suspect.

Slosh is a NON trivial problem, and abouit as amenable to numerical simulation as a supernova explosion. I doubt Elon had 50,000 hours eauivalent of CPU simulation time on slosh modeling as the recently published white dwarf supernova simulations had.

NASA is spending extran $ on a launch vehicle with active 3-rd stage attitude control (Atlas) instead of Delta for Lunar Recon Orbiter (which made room for the LCROSS experiment) due to propellant slosh concerns in the big LRO tanks on a spin-stabilized upper stage.

Atlas doesn't have a 3rd stage. It wasn't slosh, it was nutation control. Completely different behavior. Still can have nutation problems with slosh baffles. A spacecraft with a large amount of propellant still could have slosh problems on a 3 axis stablized upperstage

Jim, if I understand nutation in this context correctly (periodic 'wobbling' along an axis, presumably roll or yaw), couldn't that be compensated via an additional control system algorithim? Of course, you couldn't really write a good one until the behavior was observed in real conditions such as this event, and actually we're probably talking at this point more about refining the coefficents rather than coding the subroutine...