#1
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Electron NZ SLV
Hello All,
The New Zealand firm Rocket Lab (see: www.rocketlabusa.com ), which has several years of experience with all-composite rocket vehicles (including the Atea sounding rocket), is developing a three-stage, all-composite, small satellite launch vehicle called Electron (see: http://www.b14643.de/Spacerockets_1...ption/Frame.htm ). This SLV is 18 m long and 1 m in diameter, and it is designed to inject a nominal 110 kg payload into a 500 km Sun-synchronous orbit. Electron's first stage is powered by nine 13.3 kN thrust Rutherford pump-fed, regeneratively-cooled LOX/kerosene engines that develop an aggregate thrust of 27,000 pounds (120 kN) at launch (34,000 pounds [146 kN] in a vacuum), while the single second stage Rutherford engine (identical to the Stage 1 engines except for its vacuum-optimized nozzle) produces 4,000 pounds (18 kN) of thrust (the first stage's thrust is the same as that of the Vanguard launch vehicle). The third stage is a small solid propellant rocket motor, which appears to be spin-stabilized; the first and second stage engines are gimbaled to provide thrust vector control. Also: Here is a link to articles about the Electron launch vehicle (see: https://www.google.com/search?hl=en...0.0.scL0ah91IPU ). Whoever said Kiwis can't fly? :-)
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Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see: http://www.lulu.com/content/paperba...an-form/8075185 http://www.lulu.com/product/cd/what...of-2%29/6122050 http://www.lulu.com/product/cd/what...of-2%29/6126511 All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com. NAR #54895 SR |
#2
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That's a huge difference in thrust for the vacuum optimized nozzle. 1,000 lbs doesn't seem like much until you realize that the 1st stage individual motors only put out 3,000 lbs each.
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I love sanding. |
#3
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Quote:
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Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see: http://www.lulu.com/content/paperba...an-form/8075185 http://www.lulu.com/product/cd/what...of-2%29/6122050 http://www.lulu.com/product/cd/what...of-2%29/6126511 All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com. NAR #54895 SR |
#4
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I know that rocket motors are supposed to be more efficient in a vacuum assuming they have been designed properly, but that's a huge chunk of performance there. It makes me want to find out, but I doubt there's much information available for the engine. There's not much from the USA to compare it with either. The J-2 second stage was ignited at near vacuum so each engine should perform very close to the third stage J-2's numbers. However they are liquid hydrogen engines and it's really a double apples to oranges comparison. I can't really think of any identical 1st and 2nd stage kero/lox engines off the top of my head for a quick comparison. The original Atlas half stage engines were based off the Navajo engine design, but there were enough changes made to consider them different engines from the sustainer. I think they were both fed by a single pair turbopumps (split twin chamber, for lack of a better description). I don't recall any performance numbers of the sustainer at altitude anyway.
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I love sanding. |
#5
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In "The Promise of Space," Arthur C. Clarke included a table of exhaust velocities for various propellant combinations; their vacuum values were higher, but by a less dramatic 10% - 15%, than their sea level values, so I believe the sea level vs. vacuum thrust figures (for the same given engines) would be similar. Also:
The only "common" engine (used on a second stage as well as on a first stage) that I can think of off the top of my head is the Merlin, which powers both stages of SpaceX's Falcon 9 (the Vacuum Merlin [MVAC] has a bigger nozzle than the Stage 1 Merlin engines, of course). (Comparing the engines of the Falcon 1 would be "apples and oranges," since the first stage used a [pump-fed] Merlin, while the second stage was powered by a different, pressure-fed engine called Kestrel.) Quote:
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Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see: http://www.lulu.com/content/paperba...an-form/8075185 http://www.lulu.com/product/cd/what...of-2%29/6122050 http://www.lulu.com/product/cd/what...of-2%29/6126511 All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com. NAR #54895 SR |
#6
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Quote:
Merlin? (as in SpaceX) Oh, I see Jason beat me to it. That's what I get for skimming......
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Bernard Cawley NAR 89040 L1 - Life Member SAM 0061 AMA 42160 KG7AIE |
#7
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Quote:
__________________
Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see: http://www.lulu.com/content/paperba...an-form/8075185 http://www.lulu.com/product/cd/what...of-2%29/6122050 http://www.lulu.com/product/cd/what...of-2%29/6126511 All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com. NAR #54895 SR |
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