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#1
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Looks like Falcon 1 won't launch until at least early December.
With Christmas/New Year coming up, and more delays, and I wouldn't be suprised to see it delayed until 2006. According to Musk, "Nozzle Erosion", and the need to "complete performance testing" are the reasons for this latest delay. See: http://www.flightinternational.com/A...h+delayed.html Iain |
#2
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What causes nozzle erosion?
If its sea salt, then I suspect the longer Falcon 1 sits on a pad in the Pacific, the more erosion troubles they'll have. Fingers crossed for a successful December launch then. |
#3
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Alex Terrell wrote:
What causes nozzle erosion? If its sea salt, then I suspect the longer Falcon 1 sits on a pad in the Pacific, the more erosion troubles they'll have. Its an ablative chamber, so probably they are worried about erosion of the throat during firing. Some erosion is normal with ablative nozzles, but if it gets too much your engine can underperform or even explode. I don't think that sea salt is an issue for the nozzle, since it is made from corrosion-resistant carbon fiber composites. But other parts of the vehicle might indeed suffer a bit from long exposure to salt water. Probably the Falcon 1 sits in a "party tent" like the one they have in vandenberg, so it should be at least somewhat protected from the elements. Fingers crossed for a successful December launch then. Same here. I hope they manage to launch it this year. A successful launch would be a nice christmas present for the alt.space community. |
#5
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Its not very encouraging if the first flight of a reusable craft gets
delayed for concerns over nozzle erosion. The nozzle of the Merlin engine is expendable and ablatively cooled. According to elon musk, there is no economic case fore reusing the engine nozzle since it is a very cheap part compared to other engine parts. I think he once said that there are valves in the Merlin engine that cost more than the whole ablative nozzle. Another thing is that the engine nozzle is the part that hits the water first during recovery, so it would be quite hard to make it reusable even if it were regeneratively cooled. |
#6
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![]() Rüdiger Klaehn wrote: Its not very encouraging if the first flight of a reusable craft gets delayed for concerns over nozzle erosion. The nozzle of the Merlin engine is expendable and ablatively cooled. According to elon musk, there is no economic case fore reusing the engine nozzle since it is a very cheap part compared to other engine parts. I think he once said that there are valves in the Merlin engine that cost more than the whole ablative nozzle. Another thing is that the engine nozzle is the part that hits the water first during recovery, so it would be quite hard to make it reusable even if it were regeneratively cooled. If ever someone wants to bring back engines from orbit (as opposed to 1st stage engines) I suppose it might be cheaper to ditch the nozzle. Without the nozzle, the SSMEs might be recoverable in some sort of a pod. |
#7
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![]() Alex Terrell wrote: Rüdiger Klaehn wrote: Its not very encouraging if the first flight of a reusable craft gets delayed for concerns over nozzle erosion. The nozzle of the Merlin engine is expendable and ablatively cooled. According to elon musk, there is no economic case fore reusing the engine nozzle since it is a very cheap part compared to other engine parts. I think he once said that there are valves in the Merlin engine that cost more than the whole ablative nozzle. Another thing is that the engine nozzle is the part that hits the water first during recovery, so it would be quite hard to make it reusable even if it were regeneratively cooled. If ever someone wants to bring back engines from orbit (as opposed to 1st stage engines) I suppose it might be cheaper to ditch the nozzle. Without the nozzle, the SSMEs might be recoverable in some sort of a pod. Of course, then the problem is, how do you ditch a nozzle in orbit? You can't exactly attach a Lightband to the chamber/ nozzle interface--it would blow at engine operating temperatures. Any kind of easy disconnect would probably have the same issue. It's an interesting problem. BTW, SpaceX just added a new pic to their updates on their website, a nighttime picture of the Falcon I on Kwaj. two interesting details--one, there's no flame trench. In fact, it looks like there's not even a concrete pad below the rocket, except for in the direction of the launcher base. Two, SpaceX either painted this rocket white or it's got a significant amount of frost on it from cryo loading. tom |
#8
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![]() wrote: Looks like Falcon 1 won't launch until at least early December. With Christmas/New Year coming up, and more delays, and I wouldn't be suprised to see it delayed until 2006. According to Musk, "Nozzle Erosion", and the need to "complete performance testing" are the reasons for this latest delay. See: http://www.flightinternational.com/A...h+delayed.html Iain If this pattern of delays holds up with Falcon 9, regardless of how its lawsuit about EELV turns out, SpaceX won't have any EELV-heavy payloads to launch before 2011 anyway! After all, if Falcon 9 is currently scheduled to begin stage engine testing in late 2006 and to launch in mid 2007. The next Falcon 9 wouldn't launch until 2008 for Bigelow, and neither of those are even the 3-core S-5 and S-9 variants. Add in the delays commesurate with Falcon 1, you should expect the first (single core) Falcon 9 to roar off the pad sometime in late 2009, with the first 'heavy' variant not even launching until 2011 or so. DOD payloads, unless they're small test articles form Darpa or NRL, tend to be Heavy. Just how many heavy payloads does Musk think DOD is going to launch between 2009 and 2011 anyway? Musk must be seeing the commercial / tourism market as much more inelastic than Space Tourism groups would have you believe. Tom |
#9
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"Alex Terrell" wrote in message
oups.com... If ever someone wants to bring back engines from orbit (as opposed to 1st stage engines) I suppose it might be cheaper to ditch the nozzle. Without the nozzle, the SSMEs might be recoverable in some sort of a pod. How many SSMEs would fit in the shuttle cargo bay? The sensible approach to me seems to be to develop a small general purpose reusable orbiter and use the significant spare down mass capability to return the engines from larger 'expendable' vehicles. Presumably orbital disassembly is similar in nature to orbital assembly. Pete. |
#10
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Tom Cuddihy wrote:
[snip] Of course, then the problem is, how do you ditch a nozzle in orbit? You can't exactly attach a Lightband to the chamber/ nozzle interface--it would blow at engine operating temperatures. Any kind of easy disconnect would probably have the same issue. It's an interesting problem. On a regeneratively cooled nozzle, the outside does not get particulary warm. And on an ablative nozzle like on merlin, the interface between injector plate and nozzle is usually some kind of flange. You would just need a mechanism to open this flange, and some way to give the nozzle a small kick. If you are feeling adventurous, you might want to first open the flange, and then set off a small "hard start" using residual propellants to get the nozzle loose. BTW, SpaceX just added a new pic to their updates on their website, a nighttime picture of the Falcon I on Kwaj. two interesting details--one, there's no flame trench. In fact, it looks like there's not even a concrete pad below the rocket, except for in the direction of the launcher base. Yes, I noticed that on the environmental impact document. They just have a tiny, pyramid-shaped blast deflector. Probably they use a flame trench in vandenberg so that they can do long duration hold-down firings (and of course because it was already there). Two, SpaceX either painted this rocket white or it's got a significant amount of frost on it from cryo loading. I am sure it is the latter. |
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