SpaceX has a Kerbal moment

[Anachronda]

Looks like one of the engines on the first stage blew up. The flight computer extended the burn to deal with the missing thrust.

Video at the link: http://www.parabolicarc.com/2012/10/07/falcon-9-suffers-engine-anomoly/

[Borklund]

Update from SpaceX on the subject:

“Falcon 9 detected an anomaly on one of the nine engines and shut it down. As designed, the flight computer then recomputed a new ascent profile in realtime to reach the target orbit, which is why the burn times were a bit longer. Like Saturn V, which experienced engine loss on two flights, the Falcon 9 is designed to handle an engine flameout and still complete its mission. I believe F9 is the only rocket flying today that, like a modern airliner, is capable of completing a flight successfully even after losing an engine. There was no effect on Dragon or the Space Station resupply mission.â€Â

[Tommygun]

I like that “rapid unscheduled dis-assembly†statement in the article.

It's one thing to recover from an engine shut down and another from one blowing up.

I'm impressed that the rocket kept working.

[Tiberion]

The working theory (with armchair rocket scientists, not from SpaceX) is that the shutdown caused the explosion, rather than vice-versa - shutting down an engine when near at MaxQ (maximum atmospheric pressure where velocity and air density combine for the biggest force against the ship during ascent) will likely shatter its engine bell. Or it could have just went kerblooey and the "shutdown" was simply a matter of shutting off the fuel so it wasn't leaking out the hole

I do wonder if they recover enough of the 1st stage to discover much about it, or if its all about telemetry now.

In either event, its pretty cool and a little sobering to see that redundancy in use, especially with crew transport being a goal down the line.

[NovaSilisko]

I have a feeling that the next launch will be pushed back after they do some more digging into why this happened. Still, engine-out capability is a wonderful thing.

[Tommygun]

The working theory (with armchair rocket scientists, not from SpaceX) is that the shutdown caused the explosion, rather than vice-versa - shutting down an engine when near at MaxQ (maximum atmospheric pressure where velocity and air density combine for the biggest force against the ship during ascent) will likely shatter its engine bell. Or it could have just went kerblooey and the "shutdown" was simply a matter of shutting off the fuel so it wasn't leaking out the hole

I do wonder if they recover enough of the 1st stage to discover much about it, or if its all about telemetry now.

In either event, its pretty cool and a little sobering to see that redundancy in use, especially with crew transport being a goal down the line.

Kind of sounds like an implosion.

[Anachronda]

I have a feeling that the next launch will be pushed back after they do some more digging into why this happened. Still, engine-out capability is a wonderful thing.

As I understand it, this was to be the last launch with the model C engine. They're supposed to be moving to a new, improved model D engine.

[Shpaget]

I find it amazing that the attitude is "Oh look, an anomaly. It appears as if we have lost an engine. Oh well... The computer will adapt, no worries."

Even more amazing is that they had enough fuel to reach the planned orbit and deliver the cargo as if nothing happened.

Good engineering and planning on their part. However those flying bits and pieces don't look harmless. Those could have easily caused a chain reaction, and how many of the engines can they lose and still complete the mission?

[NovaSilisko]

I think the ceiling before range safety destroys the LV is... two? I'm not quite sure.

[phoenix_ca]

Well, all the engines draw fuel from the same source(s). Diverting more fuel to burn the other engines longer and compensate for an engine-out isn't too hard. Kinda like airplanes, where all the fuel to keep your engines going is still in the wings and fuselage (well...you hope it's still there). One engine goes out, so there's less thrust, but more fuel to burn.

I mean...you're launching a giant fuel can at speeds measured in m/s. The whole thing is a controlled explosion.

[Kryten]

As I understand it, this was to be the last launch with the model C engine. They're supposed to be moving to a new, improved model D engine.

They do have more flights with the Merlin-C engines planned, because some customers were a bit antsy about the concept of their payloads being lifted on essentially untested engines.

[Endeavour]

How many engines can the Falcon 9 lose before failing?

[sal_vager]

I read that it has double redundancy, whatever that means, maybe two engines can fail and it can still reach orbit?

[phoenix_ca]

That's a really messy question. It all depends how many it loses and at what altitude it loses them. One lost while it's high up there is peanuts to compensate for, as it's TWR is already high, and losing one isn't going to ruin that, but the lower in altitude you lose it, the worse off you are. It may well be impossible for it to reach orbit if say, by some fluke, it loses an engine or two when it's a mere 100 meters up.

[Borklund]

AFAIK it can't lose even one engine at low altitudes, say, before clearing the tower. After that, it can lose one or two engines and simply burn the fuel it carries for a longer duration to get into orbit. There is speculation that the second stage did not restart because it had no fuel left after the longer first stage burn, but I haven't seen official confirmation of that yet. Either way, the Dragon made orbit and will catch up to the ISS as scheduled. This is good news what with SpaceX working on a human rated Dragon.

Edited October 9, 2012 by Borklund

[Tauge]

This article implies that they did not reignite the second stage, which would have been used to place the Orbcomm satellite into an elliptical orbit. However, because of the longer burn, it would have released the satellite too close to ISS, for safety concerns. Orbcomm was instead released at a lower orbit than planned for that reason.

So...in the end:

Primary Mission: Success (Well it's on target to reach the ISS)

Secondary Mission: Minor Success/Possible failure, but possibly salvageable. Sierra Nevada Engineers are trying to salvage the mission.

[thorfinn]

I like that “rapid unscheduled dis-assembly†statement in the article.

It's one thing to recover from an engine shut down and another from one blowing up.

I'm impressed that the rocket kept working.

In their shoes, if I was really confident about the one-engine-out capabilities, I'd be tempted to do that on purpose just to show off

[Matokage]

Hang on! I think I can still fly it like this!

Thats what came to mind after that incident.

[sneakeypete]

From what i've heard its been confirmed the second stage not restarting with the secondary payload was due to decisions, not a second stage failure, which is good.

As for the rocket suffering failures on 2 engines and continuing on, I may be wrong, but i seem to recall hearing that the second failure cannot be on the same side as the first. Although maybe they take account of that in their operation modes, and presuming the altitude is high enough and a second engine fails a 3rd and 4th will be shut down on purpose to balance the rocket, as the remaining 5 may be enough keep the thrust to weight ratio up.

[phoenix_ca]

At that point, it sounds like less of a question of "can it still fly" and more "did we program the flight computer well enough to pull itself out of this mess?"

[karolus10]

Loosing on engine in falcon 9 aren't really big deal for a mission, but more similar glitches in the future could delay man rating of Falcon 9, which could be terrible For Spacex prestige and business future if Boeing Delta IV after man-rating Will be consider safer for carrying people than Falcon 9.

[thorfinn]

You know, if given the choice, I might prefer riding on a vehicle that has demonstrated the ability to save its payload on a number of occasions instead of one that has never failed so far, but neither proved that it can survive failure...

[karolus10]

This was rather an glitch, like broken car fender by rock lying on road - for surviving "failures" you need rather be able to eject capsule in time or risk certain death from blast .

[rdfox]

For the record, there are now exactly three launch vehicles with demonstrated engine-out capability. The Saturn V (demonstrated second-stage engine-out capability on Apollo 6 and Apollo 13), the Space Shuttle (demonstrated single-engine-out abort-to-orbit capability on STS-51F, and very nearly had to demonstrate two-engine-out transatlantic landing abort capability on that very same mission), and now the Falcon 9.

I like the redundancy, particularly in the latter phases of ascent where the effects of engine failure are much lower (indeed, on Apollo 13, the engine failure was that the second-stage center engine shut down two minutes earlier than planned--it was always supposed to shut down before the outboards, as a crude way of limiting acceleration without having to put the expense and complexity of a throttling system into the engine), but also, always remember the single-engine pilot's mantra: "Twins have a second engine because, at some point in their flight profile, they *need* it."

Even so, though, being able to recover from a full-on Kerbal-caliber engine failure like this and complete the mission objectives is a very impressive performance and has to be seen as validation of the vehicle's basic design concept.

[Tommygun]

Looks like the satellite didn't make it, but I guess they did get some useful data out of it:

http://www.space.com/18049-spacex-rocket-stranded-satellite-falls-space.html