SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION

[douglas100]

Having useless (excess) fuel on board sounds wasteful.

No, it's a good idea and it's called margin. Without margin the Dragon's mission would have been lost too.

[douglas100]

  Sucks for Orbcomm, but it's not like misdeployments don't happen with other boosters. 

At least the satellite seems to have worked properly.

http://www.spaceflightnow.com/falcon9/004/121011orbcomm/

[Prober]

This is getting incredibly boring.

1) No more on this bloody photo. And I mean no more. Don't waste your time and mine posting "But!" They WILL be deleted.

2) If you want to talk about Jim, use the Jim Discussion thread. Remember not to use the Jim Update thread, which I'll start when I know the window for his dinner time. Can someone do screenshots?

someone sure pushed the button on this one....

2) screenshots; by your command.

[MP99]

Having useless (excess) fuel on board sounds wasteful.

No, it's a good idea and it's called margin. Without margin the Dragon's mission would have been lost too.

I'm sure he's saying excess fuel over the O2 to burn it.

The prop left for the restart is a small proportion of the total upper stage prop at launch. I suspect it needs only a tiny imbalance of consumption of O2 over kero during ascent to just leave a slight imbalance of kero over O2 for the restart. Thus, enough kero but not enough O2.

cheers, Martin

[iamlucky13]

May I respectfully suggest that the engine malfunction may be another worthy concern (in addition to the illicit poster)?

To me, the SpaceX statement leaves open whether or not engine parts (fuel dome, combustion chamber, nozzle) detached from the vehicle.

In the movie that was posted, several large fragments are visible in the exhaust.  One of these has the silhouette of a nozzle, but may also be a fairing.

But perhaps the unspoken consensus to maintain a pregnant silence on this issue simply means that the nature of this incident (malfunction or disassembly) should be made known only to those who need to know it?

No. SpaceX stated unambiguously that they continued to receive telemetry from the engine. Had the engine detached, the sensors providing that telemetry would have gone with it.

Perhaps the nozzle detached, but that would surprise me since the they identified an issue in the fuel dome area, not the nozzle area. The best guess about the debris visible in the video is that it's the corner fairing.

But yes, the engine malfunction is a concern. The debate is mainly about how much of a concern.

[dcporter]

The best guess about the debris visible in the video is that it's the corner fairing.

I believe SpaceX has also said that a couple of panels in the engine were designed to blow off in the case of a pressure differential. Call it a Rapid Planned Disassembly?

[Prober]

The best guess about the debris visible in the video is that it's the corner fairing.

I believe SpaceX has also said that a couple of panels in the engine were designed to blow off in the case of a pressure differential. Call it a Rapid Planned Disassembly?

where is that advertised?

[rickl]

The best guess about the debris visible in the video is that it's the corner fairing.

I believe SpaceX has also said that a couple of panels in the engine were designed to blow off in the case of a pressure differential. Call it a Rapid Planned Disassembly?

where is that advertised?

I don't remember it being advertised, but their statement after the launch said this:

Panels designed to relieve pressure within the engine bay were ejected to protect the stage and other engines.

That's the first I heard about the panels.  I think most of the debris that was visible came from the fairing.  Someone posted photos dozens of pages ago comparing one of the pieces of debris with a photo of the top portion of the fairing.

[GalacticIntruder]

Orbcomm confirmed re-entry of satellite...

http://www.orbcomm.com/Collateral/Documents/English-US/OG2%20Prototype.pdf

Somehow it is always sad when a lot of engineering effort doesn't reach its destination. It's only nuts and bolt flying up there, but there were many people involved getting these nuts and bolts exactly into this constellation, endless discussions, endless design work, test, ...

And also it is amazing to me to learn a situation, where you have only a couple of hours to test your masterpiece. I wonder if they have plans exactly for scenarios like this, where time is very limited, or if they just make adhoc decisions what to test. (Reading the word adhoc in this context I actually can't believe, that there no plans).

Too bad for Orbcomm it was a quick loss, at least it was insured.

[rickl]

Once their investigation is complete, I hope SpaceX produces a short animated video showing the sequence of events.  They have a good video department.

[R.Simko]

Since there is only one more launch scheduled with the Merlin 1C engines, I wonder if SpaceX's better move would be to move directly to launching with Merlin 1D engines.  This way they can show a history more quickly of the new engine.  This may allay concerns over limited flight history of the Merlin 1D when NASA is selecting which company(s) win crewed commercial contracts.  Of course this would also depend on how soon they can have a full set of Merlin 1D engines ready.

Someone else had mention yesterday that the extra Merlin 1C engines can be used on Grasshopper trials.  This way the engined would not be wasted.

[Comga]

Some good reading:  http://www.newscientist.com/blogs/shortsharpscience/2012/10/satellite-ride-sharers-spacex.html

key quote:

"While there was sufficient fuel on board to [lift the satellite], the liquid oxygen on board was only enough to achieve a roughly 95 per cent likelihood of completing the second burn, so Falcon 9 did not attempt a restart," says SpaceX spokesperson Katherine Nelson.

Does that imply that a successful mission would have had one second stage restart?  that would leave that second stage in the 350 by 7XX km transfer orbit that continuously crosses the altitude of the ISS.  I know the orbit of an empty stage should decay relatively fast, but it would have to lose over 300 km of perigee to fall below the ISS orbit

[Lars_J]

Since there is only one more launch scheduled with the Merlin 1C engines, I wonder if SpaceX's better move would be to move directly to launching with Merlin 1D engines.  This way they can show a history more quickly of the new engine.  This may allay concerns over limited flight history of the Merlin 1D when NASA is selecting which company(s) win crewed commercial contracts.  Of course this would also depend on how soon they can have a full set of Merlin 1D engines ready.

Not easily. The M1D is designed for the F9v1.1, and vice versa. The thrust is different, the attachment points are different. It would be easier to just use the 1.1 instead of switching out engines.

Someone else had mention yesterday that the extra Merlin 1C engines can be used on Grasshopper trials.  This way the engined would not be wasted.

I don't think so. The M1C is incapable of throttling, making it useless for Grasshopper.

[R.Simko]

Since there is only one more launch scheduled with the Merlin 1C engines, I wonder if SpaceX's better move would be to move directly to launching with Merlin 1D engines.  This way they can show a history more quickly of the new engine.  This may allay concerns over limited flight history of the Merlin 1D when NASA is selecting which company(s) win crewed commercial contracts.  Of course this would also depend on how soon they can have a full set of Merlin 1D engines ready.

Not easily. The M1D is designed for the F9v1.1, and vice versa. The thrust is different, the attachment points are different. It would be easier to just use the 1.1 instead of switching out engines.

Someone else had mention yesterday that the extra Merlin 1C engines can be used on Grasshopper trials.  This way the engined would not be wasted.

I don't think so. The M1C is incapable of throttling, making it useless for Grasshopper.

Thanks Lars.  I was thinking they would move directly to F9v1.1.  I know I didn't make that clear.  If that means that they can't use any of the last F9v1, then maybe it wasn't as good and idea as I hoped it was.

[Confusador]

These verification successes achieved from the single prototype satellite validate that the innovative OG2 satellite technology operates as designed before launching the full constellation of OG2 satellites.
...
The Company has filed a notice of claim under its launch insurance policy for a total loss of the OG2 prototype.

I love the nature of press releases.  "It was a success!  But it was also a total failure."
I kid, of course; I can hardly blame them for filing a claim after a clear failure, and I'm glad they got some good data back.  It's still funny.

[Robotbeat]

How long after the shuttle ATO did the next mission fly? (next month!)

But that ATO was found to be caused by a bad sensor, was it not? So there wasn't really anything to fix except the sensor, and therefore no reason for a stand-down longer than it took to find out what the problem was.

Wasn't the only time there was a Shuttle engine out.

[Robotbeat]

How long after the shuttle ATO did the next mission fly? (next month!)

But that ATO was found to be caused by a bad sensor, was it not? So there wasn't really anything to fix except the sensor, and therefore no reason for a stand-down longer than it took to find out what the problem was.

Wasn't the only time there was a Shuttle engine out.

Only one in-flight, though.

Sts 93 had engine damage (two concurrent issues, actually) due to an oxygen post flying off and making a whole in the coolant lines which led to premature engine shutdown, along with an engine controller failure. Lower than planned orbit.

[LouScheffer]

Many people aren't going to like me for this, but given the now-confirmed improper Orbcomm orbit result, my methodology requires me to categorize this as a launch vehicle failure. 

Those familiar with my system know that I list launches as successes if proper orbits are achieved, and failures if not, without compromise.  I show three Space Shuttle failures and one Atlas 5 failure, for example.  I list SA-502/Apollo 6 as a failure. 

I think it's fairly obvious to the casual observer that this launch succeeded at its primary objective (deploy Dragon such that it can berth with the ISS) and failed at it's secondary objective (deploy OrbComm in it's proper orbit).

I understand the desire for a black and white pass/fail criteria, but saying this launch is a complete failure seems a bit much.  Did you mark down Falcon 9 Flight 1 as a failure since it failed to achieve a restart burn?

I don't know how you can come to that conclusion as well. It was not the second stages fault that the command was not given to raise Orbcomm's satellite to it's proper orbit. NASA's parameters did not allow for it. I would classify the mission as a partial success and that is only if and when Dragon fulfills it's intended flight plan.

You're conflating the Dragon mission and the Falcon launch. We traditionally separate reliability studies of rocket and payload because they are largely independent. Whether the Dragon mission succeeds or not, Falcon delivered it to substantially the correct orbit.
  And you are partly incorrect about the 'command' - there was no external command, it was a second stage program and the reason it didn't pass NASA's parameters was because of the first stage issues. So it was the Falcon's fault (the first stage, not the second stage, though,  you're right to that extent).

The problem here is that there's 'secondary' and 'secondary'. The Falcon 1 restart test was a launch vehicle provider's 'nice to have'. The Falcon 9 Orbcomm deploy was a customer's 'must have'. I would classify both of those missions as partial success, the Falcon 1 at 90/95 percent and this one at 85 percent.

This being America, we can put a price on anything.  It look like the primary customer (NASA) paid $133.3M and got exactly what they paid for.  It looks like OrbComm paid at most $3.5M (They said the satellite cost $6.5M and the insurance of $10M would cover satellite + launch costs).  So if we consider OrbComm a complete failure, then the score for this mission is 133.3/(133.3+3.5) = 97.4%.

[Jim]

This being America, we can put a price on anything.  It look like the primary customer (NASA) paid $133.3M and got exactly what they paid for.  It looks like OrbComm paid at most $3.5M (They said the satellite cost $6.5M and the insurance of $10M would cover satellite + launch costs).  So if we consider OrbComm a complete failure, then the score for this mission is 133.3/(133.3+3.5) = 97.4%.

1.  Costs are not the methodology used to compute mission success
2.  Anyways, your numbers are wrong.  OrbComm launch and spacecraft costs must be included since the NASA number also included all costs.  Or just use about $50 million for NASA launch costs.

[Antares]

I believe SpaceX has also said that a couple of panels in the engine were designed to blow off in the case of a pressure differential. Call it a Rapid Planned Disassembly?

where is that advertised?

June 2005 http://www.spacex.com/updates_archive.php?page=0605-1205

Then there is the question of dealing with the comparatively rare case of a chamber rupture. To protect against this, Falcon 9 will have a blast shield protecting the entire base of the vehicle just above the gimbal joints of the engines. In addition, there will be fireproofed Kevlar fragment containment around each engine, similar to those present in jet engine nacelles. The explosive power of a liquid rocket chamber is actually not exceptionally high – it can be thought of as simply a small pressure vessel containing (in our case) 800 psi hot gas. During the development of Merlin, we saw several of what we refer to as RUD (rapid unscheduled disassembly) events and no fragments have ever penetrated more than 2mm of aluminum. Also, the direction of fragments is in a shallow downward cone away from the vehicle.

As additional measures of protection, all propellant and pneumatic lines have either pre-valves or check valves nested up high in the thrust structure. If anything happens to the engine, the flight computer is able to cut off all propellant and pressurant flow immediately.

Also August 2007 http://www.spacex.com/updates_archive.php?page=081707

If you want to look in a specific place for something on Google, you can do an analog to what I did for this, i.e.
kevlar site:spacex.com