LIVE: Falcon 9 Flight 1 Maiden Flight - June 4, 2010

[corrodedNut]

I really don't know. I saw move just once, as you said. It was pretty quick when it did. Maybe too quick to notice it when the webcast stuttered.  AFAIK, the thing is elecrical not hydraulic, so leaking fluids wouldn't have mattered.  So it could have failed all on its own, but I hate to heap on amateur sleuth gotchas onto an essentially nominal flight.

[Ben the Space Brit]

FWIW, I still think that they deliberately overrode the vehicle's attempt to compensate to get as much data as possible on the problem.

If the object seen over Australia was the F9US, had the roll rate continued to increase? If not, then we know it was something to do with the engine, intentional or otherwise.

IIRC, I saw two bursts from the roll control motors, one 45-degree right and one 30 degree left, all towards the beginning of the upper stage burn.

[yinzer]

I definitely remember hearing that you don't strictly need roll control. If the roll is too fast you have issues of course; at some point the thrust vector control won't be able to move the nozzle in a cone fast enough, or the propellant can move away from the tank outlet.

I'm not sure if anyone leaves roll control off these days, but I'm pretty sure that roll control failures have been survived before.   

[Chris Bergin]

I think you may have cleaned out some of the references to this Chris, removing this is quite understandable, but I just wanted to share it.

Yeah, but because it had spread over three pages in responses (myself included), so I trimmed back.

Speaking of NASA, right after China note they are investing in their future goals, and SpaceX have this success, the next article - going on later today - really nails down how times are changing, via the downside of the transition The timing isn't deliberate, today is an open slot for the news to go on.

[Jim]

FWIW, I still think that they deliberately overrode the vehicle's attempt to compensate to get as much data as possible on the problem.

Why are you repeating this?

There is no such thing as over riding anything.  All Launch vehicles are autonomous.  They don't have the capability to receive commands, except for destruct.

[edkyle99]

I definitely remember hearing that you don't strictly need roll control. If the roll is too fast you have issues of course; at some point the thrust vector control won't be able to move the nozzle in a cone fast enough, or the propellant can move away from the tank outlet.

I'm not sure if anyone leaves roll control off these days, but I'm pretty sure that roll control failures have been survived before.   

The Falcon 9 second stage has to have three-axis control - during and after Merlin burns, if it is ever going to perform GTO missions (for which it has held contracts).  Such missions require coast intervals with the stage under control.  They also sometimes require controlled spin rates imparted to the satellites prior to separation, etc.

The Australia observations tell us that the stage had not regained roll control even 40-45 minutes after the Merlin burn was completed.

 - Ed Kyle

[Jim]

1) We all saw the violent 90-degree roll the vehicle made at launch and the flame from the LOX line as it dropped away (probably the residual GOX igniting the hot exhaust gasses and burning away).  I wonder if the roll tore the lox hose connection loose and it was still attached the vehicle.  During the ascent, the valve may have loosened (it was never suppose to remain closed with the hose attached in flight, after all) and oxygen started leaking out, creating a slight off-axis thrust from the partially-open valve.

There was no flame, just liquid flashing into vapor, which is no big deal.  Look at old Thor and Atlas launches, there is vapor venting from the umbilicals.

The vehicle would not have made it to orbit with the fill and drain open.

[psloss]

Little bit of the view from the Visitor Complex...FWIW...

[ugordan]

The Falcon 9 second stage has to have three-axis control - during and after Merlin burns, if it is ever going to perform GTO missions (for which it has held contracts).

Technically, yes, although I'd disagree about the need for RCS during the first burn since the engine itself controls all 3 axes. The assumption you're making - and we really don't know at this point if it's true or false - is that this stage really was a fully operational stage. It could have been a stripped version due to schedule pressure, etc. Meaning no RCS.

That might also explain the 2nd engine restart "burp" where they just started it for an odd chance the propellant was setttled and shut it down immediately because they had no way of controlling the burn direction. Or the burp could have been a failed restart.

[edkyle99]

The Falcon 9 second stage has to have three-axis control - during and after Merlin burns, if it is ever going to perform GTO missions (for which it has held contracts).

Technically, yes, although I'd disagree about the need for RCS during the first burn since the engine itself controls all 3 axes. The assumption you're making - and we really don't know at this point if it's true or false - is that this stage really was a fully operational stage. It could have been a stripped version due to schedule pressure, etc. Meaning no RCS.

That might also explain the 2nd engine restart "burp" where they just started it for an odd chance the propellant was setttled and shut it down immediately because they had no way of controlling the burn direction. Or the burp could have been a failed restart.

FWIW, I reviewed the on-board video of the roll.  The roll started at about T+5m.  The stage then performed four rolls during the remainder of the burn.  The roll times were as follows.
Roll 1:  60 sec
Roll 2:  49 sec
Roll 3:  31 sec
Roll 4:  ~20sec (video drop out prevented precise timing)

It would be very interesting to learn what the roll rate was some time after the burn.  Observers will have to act quickly, however.  There are indications that this stage may reenter after only a few weeks.

 - Ed Kyle

[clongton]

That might also explain the 2nd engine restart "burp" where they just started it for an odd chance the propellant was setttled and shut it down immediately because they had no way of controlling the burn direction. Or the burp could have been a failed restart.

Granted this is just an opinion, but by calling SECO-1 it seems to me that restart and SECO-2 was likely intended. The excessive roll however was not intended and by the time US restart was planned would have made a 2nd burn untenable. So, imo they accomplished the 2nd ignite, to validate the hardware and software, and then shut it down to avoid loosing the vehicle because of an uncontrollable burn vector. Thus the "burp". Just IMO of course. YMMV. Let's see if SpaceX provides more detail as the coming days unfold.

[Robotbeat]

That might also explain the 2nd engine restart "burp" where they just started it for an odd chance the propellant was setttled and shut it down immediately because they had no way of controlling the burn direction. Or the burp could have been a failed restart.

Granted this is just an opinion, but by calling SECO-1 it seems to me that restart and SECO-2 was likely intended. The excessive roll however was not intended and by the time US restart was planned would have made a 2nd burn untenable. So, imo they accomplished the 2nd ignite, to validate the hardware and software, and then shut it down to avoid loosing the vehicle because of an uncontrollable burn vector. Thus the "burp". Just IMO of course. YMMV. Let's see if SpaceX provides more detail as the coming days unfold.

I bet they planned on only a short restart to begin with, just so it couldn't possibly screw up the orbit too much. They wanted to reach orbit, here. They didn't want anything to get in the way of that (besides safety, of course).

[ELinder]

First time poster here. I watched from the KSC Saturn V center, and this thread was a godsend for keeping up with what was going on. They made an occasional PA announcement, but nothing else. This rocket has a great sound. It was far louder, deeper, and lasted much longer than I was expecting. This was the view from the top of the shuttle viewing grandstand with a telephoto lens.

Erich

[clongton]

You know I have to tell you all that I have watched the launch probably 50-60 times now, from all different angles and I still get a lump in my throat every time. I have goose bumps on my arm even now, a day and a half later, as I write this. That was just a totally awesome launch. As partial as I am to seeing the Shuttle launch, there is just NOTHING like the throaty roar of a LOX/RP-1 engine splitting the sky on the way up - nothing! I loved that launch! It's been said over and over again on this forum in several different threads, but I just have to say it again; congratulations to Elon Musk, to SpaceX, to the entire team that worked so hard to set this bird free into the air, and to all the people who believed in SpaceX that this day would come.

[Chris Bergin]

First time poster here. I watched from the KSC Saturn V center, and this thread was a godsend for keeping up with what was going on. They made an occasional PA announcement, but nothing else. This rocket has a great sound. It was far louder, deeper, and lasted much longer than I was expecting. This was the view from the top of the shuttle viewing grandstand with a telephoto lens.

Erich

Welcome to the site's forum, appreciate the nice words, and thanks for the cool photo

[Lee Jay]

FWIW, I still think that they deliberately overrode the vehicle's attempt to compensate to get as much data as possible on the problem.

Why are you repeating this?

There is no such thing as over riding anything.  All Launch vehicles are autonomous.  They don't have the capability to receive commands, except for destruct.

Well, and except for Shuttle, of course (through the radio).

[Downix]

You know I have to tell you all that I have watched the launch probably 50-60 times now, from all different angles and I still get a lump in my throat every time. I have goose bumps on my arm even now, a day and a half later, as I write this. That was just a totally awesome launch. As partial as I am to seeing the Shuttle launch, there is just NOTHING like the throaty roar of a LOX/RP-1 engine splitting the sky on the way up - nothing! I loved that launch! It's been said over and over again on this forum in several different threads, but I just have to say it again; congratulations to Elon Musk, to SpaceX, to the entire team that worked so hard to set this bird free into the air, and to all the people who believed in SpaceX that this day would come.

I wish I'd seen it in person, but friday I work.  Not this upcoming week tho, driving over to the cape so my son can finally go to the cape.

But I was there watching, and the noise I hear on my speakers here is so different than what I am used to.

[deltaV]

There is no such thing as over riding anything.  All Launch vehicles are autonomous.  They don't have the capability to receive commands, except for destruct.

Well, and except for Shuttle, of course (through the radio).

Is there a good reason that unmanned vehicles are traditionally fully automated with no override possible whereas manned vehicles have manual overrides?  Remote control (mission control radioing instructions) was certainly used a lot during Apollo and Shuttle to help deal with the unexpected. Wouldn't remote control capability be useful occasionally for unmanned vehicles? Possible reasons for this apparent discrepancy:

1. Overrides on manned vehicles are needed for psychological reasons to give the astronauts a feeling of control over their own destiny. So a manned vehicle without overrides isn't a reasonable option. On unmanned vehicles there's no such requirement, and cost-benefit analysis may not support the development of remote control for the one in a few hundred missions that it would save.

2. Communication with the ground may be too slow and/or unreliable for remote control to work. (IIRC there's a orbital communication network that's far slower than speed of light considerations would suggest.)

3. Rocketry traditions have yet to adapt to the advancement in computers over the past half-century. (Which would be ironic given the contribution of rockets to the early miniturization of computers!)

4. Maybe getting regulator approval for a remote-controlled rocket would be tricky.

[nooneofconsequence]

The only thing you might be referring to is that in certain situations with flight control software you have constraints that  shut down certain control actions when they do aberrant things.

Such as when you apply a control to mitigate an issue ... and that appears to make it worse or have no effect. You don't want to make things worse.

A lot of issues with initial tests of new software involve constraints that are often set wrong or need adjustment...

[deltaV]

One example of a shuttle assent where manual control may have saved the day was STS-51-F. This shuttle flight had one SSME shut down early due to sensor failure. A second engine sensor was misbehaving and they inhibited the auto shut-down to prevent a loss of another engine.

See
http://en.wikipedia.org/wiki/STS-51-F
http://www.jsc.nasa.gov/history/roundups/issues/85-08-09.pdf