SpaceX - Falcon 1: Flight 4

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frodo1008

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Wow, big congrats to SpaceX.&nbsp; Hopefully this marks the start of many successful flights for them.&nbsp; Having this manner of low cost orbital flight available will be a boon for everyone, I believe.&nbsp; Onward and upward!&nbsp; <br /> Posted by tanstaafl76</DIV></p><p>Not only do I hope that they can truly reduce the price of launches but between them and t-space both being mainly located in Southern California they might just bring back a large part of the aerospace industry that the last two decades or so have seen lost from here.&nbsp; </p><p>I really hate it when people seem to think that you can replace an industry with good wages and benefits with something like retail.&nbsp; As we have seen with the recent demise of many retail higher priced specialty shops if you don't have a relatively well off middle class eventually there is none to buy and support even the retail industry itself! </p><p>Oh, I know that in trying to have far less expensive operations these alt.space outfits are not going to exactly pay as well as the older outfits did, but you can't get the kind of help that such high tech operations demand without relatively good pay and benefits. &nbsp; Not only do you need good engineering, but you also need such relatively high paid manufacturing types as: machinists, precision inspectors, aerospace type assemblers, welders, and a host of other support people.&nbsp; These are generally people with a lot of education and specialized training, and you don't get that kind of help for $10 and hour or less.&nbsp; And that is all to the good of the economy in general.&nbsp;&nbsp;</p><p>So, not only because I fully support mankind truly going out into space, but also because I fully support a good economy for the US itself I fully hope that these new alt.space outfits can really do what the say they can!! </p><p>And personally I see no reeason why they can't. </p>
 
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windnwar

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Not only do I hope that they can truly reduce the price of launches but between them and t-space both being mainly located in Southern California they might just bring back a large part of the aerospace industry that the last two decades or so have seen lost from here.&nbsp; I really hate it when people seem to think that you can replace an industry with good wages and benefits with something like retail.&nbsp; As we have seen with the recent demise of many retail higher priced specialty shops if you don't have a relatively well off middle class eventually there is none to buy and support even the retail industry itself! Oh, I know that in trying to have far less expensive operations these alt.space outfits are not going to exactly pay as well as the older outfits did, but you can't get the kind of help that such high tech operations demand without relatively good pay and benefits. &nbsp; Not only do you need good engineering, but you also need such relatively high paid manufacturing types as: machinists, precision inspectors, aerospace type assemblers, welders, and a host of other support people.&nbsp; These are generally people with a lot of education and specialized training, and you don't get that kind of help for $10 and hour or less.&nbsp; And that is all to the good of the economy in general.&nbsp;&nbsp;So, not only because I fully support mankind truly going out into space, but also because I fully support a good economy for the US itself I fully hope that these new alt.space outfits can really do what the say they can!! And personally I see no reeason why they can't. <br />Posted by frodo1008</DIV></p><p>&nbsp;I whole heartedly agree with that view as well. They probably won't hire as many workers as some of the aerospace giants of the past employed in that region as they'll definately lean toward keeping it lean and mean and as far from traditional corporate structures as possible but the workers will definately be well paid for everything they are creating. I look forward to seeing many more launches from them in the future. May they all go as well. Just watching the speed of them being able to get another rocket on the pad and launched is a huge benefit, something that is not the normal in space launch. Darpa and DOD will be buying alot of rockets from them if they can keep up the rapid turn around rate. <br /></p> <div class="Discussion_UserSignature"> <p> </p><p><font size="2" color="#0000ff">""Only two things are infinite, the universe and human stupidity, and I'm not sure about the former." --Albert Einstein"</font></p> </div>
 
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frodo1008

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>&nbsp;I whole heartedly agree with that view as well. They probably won't hire as many workers as some of the aerospace giants of the past employed in that region as they'll definately lean toward keeping it lean and mean and as far from traditional corporate structures as possible but the workers will definately be well paid for everything they are creating. I look forward to seeing many more launches from them in the future. May they all go as well. Just watching the speed of them being able to get another rocket on the pad and launched is a huge benefit, something that is not the normal in space launch. Darpa and DOD will be buying alot of rockets from them if they can keep up the rapid turn around rate. <br /> Posted by windnwar</DIV></p><p>Do remember though that being that quick with a rocket that is the approximate size of a German V2 of WWII is not paticularily an indicator of how fast one can set up a rocket of even the Delta II class, let alone one of the Delta IV Heavy class.&nbsp; That is a very different thing entirely!</p><p>In fact, I would not want to see anybody being "fast" with rockets that large! </p><p>However, I am not being pessimistic here, just realistic.&nbsp; And I do think that they could have at least somewhat less of a launch crew even with the larger rockets (by the way even ULA has a far less crew when they launch their far larger rockets for pure commercial launches also).&nbsp; After all, they already have shown that this type of business can be profitable. &nbsp; </p>
 
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vulture4

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>, they already have shown that this type of business can be profitable. &nbsp; <br /> Posted by frodo1008</DIV></p><p>True, if the customer is the government. </p><p>There have been numerous proposed designs that could launch payloads for a fraction of the cost of the Delta II, but it does one thing none of them have done so far .. it makes a profit. When SpaceX actually starts launching payloads, I'll be suprised if it's much cheaper. </p><p>And that's a problem, because in the last two years I can recall only one commercial launch from Cape Canaveral, and that was because the customer couldn't get the ride they originally wanted. ULA has two pretty good medium-lift ELVs and no commercial cusomers. How is SpaceX going to get any? While it has a good, modern design, in truth so does the Delta IV.&nbsp;Whether SpaceX can win customers from Ariane, Sea launch, ILS, and China remains to be seen. </p>
 
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frodo1008

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>True, if the customer is the government. There have been numerous proposed designs that could launch payloads for a fraction of the cost of the Delta II, but it does one thing none of them have done so far .. it makes a profit. When SapceX actually starts launching payloads, I'll be suprised if it's much cheaper. And that's a problem, because in the last two years I can recall only one commercial launch from Cape Canaveral, and that was because the customer couldn't get the ride they originally wanted. ULA has two pretty good medium-lift ELVs and no commercial cusomers. How is SpaceX going to get any? While it has a good, modern design, in truth so does the Delta IV.&nbsp;Whether SpaceX can win customers from Ariane, Sea launch, ILS, and China remains to be seen. <br /> Posted by vulture4</DIV></p><p>You are correct, there are indeed very few commercial launches by ANY US launch provider.&nbsp; The reason for this is obvious (especially as most commercial launches are by Russian rockets), and that is the difference in the living standards and therefore the costs of personnel between the two countries.&nbsp; The Russians in particular can afford to then launch at a far lower price than can any American launch service.&nbsp; The only exception to this is Sea Launch, which however uses Ukrainian launchers itself.&nbsp; They are even causing considerable problems for Arianspace which used to be the major commercial launch provider of the world (and still holds more launches than the US for commercial purposes), but not anymore, the Russians have also taken their place!</p><p>Therefore, spacex MUST be a good bit cheaper (while being just as reliable) as any of the launchers of other countries in the world, if it even hopes at all to just be a competitive commercial launch system!</p><p>Under those circumstances I really do wish them many successful launches at a far lower cost.&nbsp; Otherwise, I am afraid the enterprise will fail due to an unleveled international playing field.&nbsp; And that would be a true pity for even the world at large let alone for the US!! </p>
 
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rocketscientist327

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Why are you conservative types always having to pick some kind of a fight?&nbsp; Here you are picking one where there isn't even one to be poked.&nbsp; I know of nobody that does not wish Elon Musk and spacex all the good launches in the world!Now spacex simply needs to establish that they can do this again, and again, and again, like the people that have launched dozens of Delta II vehicles.&nbsp;&nbsp; That is NOT pessimism, it is truth.&nbsp; Not only truth but even capitalistic truth, for if you can not establish a very good record of reliability then the people that want to launch their satellites and other items into orbit are not going to pay you to launch.&nbsp; That is capitalism of the finest type. &nbsp;By the way I do think that both Boeing and LM (and the new combination of the two in ULA) are also private companies.&nbsp; At least you can but their stock on the New York Stock Exchange. So I think that also qualifies them as private also!!In fact all throughout the history of NASA they have NOT built their own rockets, but have bought their equipment and launches from private industry, it is one of the things that actually makes NASA one of the best of the governmental agencies! <br />Posted by frodo1008</DIV><br /><br />Conservitive types???&nbsp; What exactly do you mean?&nbsp;</p><p>The people who have been overly critical of SpaceX and Elon are people who are deeply invested in Delta and Atlas.&nbsp; DOCM has been a supporter of SpaceX in t he past.&nbsp; Granted, I really haven't been on much due to a hiatus in Afghanistan, but last year I know he defended SpaceX after flight #2.</p><p>&nbsp;Respectfully,</p><p>Rocket Scientist 327</p>
 
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vattas

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<p>Just&nbsp; after MECO and before stage separation booster seems to perform pitch. After stage separation second stage returns to previous course. Is this pitch intentional or is it some after-effect of MECO (seems unlikely)? If it's intenional, then why it is needed? </p><p>I remember the same pitch during 2nd flight.</p>
 
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shuttle_guy

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Any thoughts on the oscillations at T+5:50~6:20? They looked very similar to the onset of oscillations in Flight 2.Here's the uncut webcast replayed.... http://www.youtube.com/watch?v=eGHWheEM-ww <br />Posted by dwightlooi</DIV></p><p>&nbsp;</p><p>I suspect minor updates to the flight control software will address the oscillations. (The software and hardware was modified to solve the problem which caused the loss of flight 2)<br /></p> <div class="Discussion_UserSignature"> </div>
 
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frodo1008

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>&nbsp;I suspect minor updates to the flight control software will address the oscillations. (The software and hardware was modified to solve the problem which caused the loss of flight 2) <br /> Posted by shuttle_guy</DIV></p><p>Well now that they have had a good flight, hopefully they can keep it up and establish a good to excellent flight record for this rocket!</p><p>Next, they need to do the same for the larger Falcon 9. And if they can really do this and make a profit at the prices that they quote, the US WILL then have a truly competitive launch system.&nbsp; Even the Russians can not go too low in their pricing, so this is indeed a possibility.</p><p>Them NASA will have a true competition for a low cost system.&nbsp; Which I think will actually be good for ULA also, as they will then have to make efforts to lower their prices to NASA in order to retain a part of the market share!</p><p>The truly great thing is that (once again, if they can still actually make a profit while remaining reliable) spacex should indeed bring back a large part of the commercial launch business with competitive pricing, which I think is all to the good of not only the US, but the entire space industry itself.&nbsp; </p><p>By getting the pricing of launches down to the relatively magic number of about $1,000 per pound to LEO there will be many more applications for satellites, and even other items (such as Bigelows' space stations) to be opened up also!</p><p>This could be the true beginning of a very large and profitable private space industry (which would also be very good for governmental pricing as well).</p><p>I will admit to having some reasonable doubts, but am more than happy to have been wrong!! </p>
 
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job1207

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<p>The negativity that followed the previous launches, contrasted with the relative jubilation seen here after a successful launch makes me think of a sports team. </p><p>Here is hoping that they can maintain quality and throughput enough to make money. </p><p>On to the Falcon IX, next year.&nbsp; </p>
 
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Swampcat

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>I will admit to having some reasonable doubts, but am more than happy to have been wrong!! <br /> Posted by frodo1008</DIV></p><p>frodo, I think most of us had reasonable doubts and will continue to have reasonable doubts about SpaceX's continued success until SpaceX develops a track record that instills confidence in its products. As most reasonable people know, rocket science and engineering is extremely difficult and unforgiving of mistakes. Add to this the way SpaceX is trying to do things somewhat differently in order to lower the cost of orbital access and it is not unreasonable to question whether they can succeed in doing so.</p><p>They've had a great success and my hope is that they can continue to succeed and earn a profit at the same time. For me, SpaceX represents the future of humanity beyond Earth. Governments will not be able to do all the things us space cadets want to see done. It will take the efforts of private groups like SpaceX, in cooperation with government efforts, to make it happen.</p> <div class="Discussion_UserSignature"> <font size="3" color="#ff9900"><p><font size="1" color="#993300"><strong><em>------------------------------------------------------------------- </em></strong></font></p><p><font size="1" color="#993300"><strong><em>"I hold it that a little rebellion now and then is a good thing, and as necessary in the political world as storms in the physical. Unsuccessful rebellions, indeed, generally establish the encroachments on the rights of the people which have produced them. An observation of this truth should render honest republican governors so mild in their punishment of rebellions as not to discourage them too much. It is a medicine necessary for the sound health of government."</em></strong></font></p><p><font size="1" color="#993300"><strong>Thomas Jefferson</strong></font></p></font> </div>
 
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MeteorWayne

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Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Posted by Swampcat</DIV><br /><br />Well said. <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>
 
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dwightlooi

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<p>The three things I like about SpaceX are:-</p><p>(1)<strong> It is a privately funded business whose business model is dollars for achievement and not cost plus fee.</strong></p><p>(2) <strong>It is a company which strives to make money and not an industry player whose purpose of existence is more a government funded job creation and retention scheme than anything else.</strong> It has been said that the aerospace industry in the USA is "Welfare for the Middle Class". I cannot agree more and I am against welfare for any class. An entity whose function is to create and market a good or service that is in demand in exchange for a price the market will bear is what we need. All entities whose function is first to provide employment and benefits, then find something for the employed to do which may or may not be worthwhile is the root of all evil.</p><p>(3) <strong>This is the closest yet to the Minimum Cost Design / Space Launch Vehicle (MCD/SLV) of the late 60s</strong> -- something which I have been screaming for the resurrection of. Pintle Engine, pressure fed upper stage, unfussy fuels,&nbsp; </p>
 
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Swampcat

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>The three things I like about SpaceX are:-(1) It is a privately funded business whose business model is dollars for achievement and not cost plus fee.(2) It is a company which strives to make money and not an industry player whose purpose of existence is more a government funded job creation and retention scheme than anything else. It has been said that the aerospace industry in the USA is "Welfare for the Middle Class". I cannot agree more and I am against welfare for any class. An entity whose function is to create and market a good or service that is in demand in exchange for a price the market will bear is what we need. All entities whose function is first to provide employment and benefits, then find something for the employed to do which may or may not be worthwhile is the root of all evil.(3) This is the closest yet to the Minimum Cost Design / Space Launch Vehicle (MCD/SLV) of the late 60s -- something which I have been screaming for the resurrection of. Pintle Engine, pressure fed upper stage, unfussy fuels,&nbsp; <br /> Posted by dwightlooi</DIV></p><p>I agree with all of the above, though I would suggest that there is a role for the cost plus providers when it comes to national security issues. This is a traditional role for the dinospace companies and their accomplishments in this regard should be given appropriate accolades.</p><p>OTOH, the dinospace companies, as long as they continue to do business the old fashioned way, will not be the ones carrying us into the future beyond government projects. Their responsibilities to their shareholders and reliance on government contracts have generally made them unwilling to take the kinds of risks SpaceX and other newspace companies are taking. Historically, it usually takes someone outside the mainstream to come along with innovative ideas that upset the status quo and bring about major changes.&nbsp;</p> <div class="Discussion_UserSignature"> <font size="3" color="#ff9900"><p><font size="1" color="#993300"><strong><em>------------------------------------------------------------------- </em></strong></font></p><p><font size="1" color="#993300"><strong><em>"I hold it that a little rebellion now and then is a good thing, and as necessary in the political world as storms in the physical. Unsuccessful rebellions, indeed, generally establish the encroachments on the rights of the people which have produced them. An observation of this truth should render honest republican governors so mild in their punishment of rebellions as not to discourage them too much. It is a medicine necessary for the sound health of government."</em></strong></font></p><p><font size="1" color="#993300"><strong>Thomas Jefferson</strong></font></p></font> </div>
 
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moonmadness

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>The negativity that followed the previous launches, contrasted with the relative jubilation seen here after a successful launch makes me think of a sports team. Here is hoping that they can maintain quality and throughput enough to make money. On to the Falcon IX, next year.&nbsp; <br />Posted by job1207</DIV><br /><br />SpaceX web site still shows falcon 9 launch for this year(target date). :)</p><p>I would be immensely impressed if they pull that off.</p> <div class="Discussion_UserSignature"> <p>I'm not a rocket scientist, but I do play one on the TV in my mind.</p> </div>
 
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docm

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<p>The dates on their manifest are when the rocket will be delivered to the launch complex, not the launch date.&nbsp; The Q4 '08 Falcon 9 is actually scheduled for launch Q1 of '09.</p><p><strong>Quote:</strong></p><em> *Target dates are for vehicle arrival at launch site.</em> <div class="Discussion_UserSignature"> </div>
 
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shuttle_guy

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>The dates on their manifest are when the rocket will be delivered to the launch complex, not the launch date.&nbsp; The Q4 '08 Falcon 9 is actually scheduled for launch Q1 of '09.Quote: *Target dates are for vehicle arrival at launch site. <br />Posted by docm</DIV></p><p>I will try to find time to drive over to Pad 40 to checkout the Falcon 9 facility status.<br /></p> <div class="Discussion_UserSignature"> </div>
 
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vulture4

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>The three things I like about SpaceX are:-(1) It is a privately funded business whose business model is dollars for achievement and not cost plus fee.(2) It is a company which strives to make money and not an industry player whose purpose of existence is more a government funded job creation and retention scheme than anything else. </p><p>.(3) This is the closest yet to the Minimum Cost Design / Space Launch Vehicle (MCD/SLV) of the late 60s -- something which I have been screaming for the resurrection of. Pintle Engine, pressure fed upper stage, unfussy fuels,&nbsp; <br /> Posted by dwightlooi</DIV></p><p>SpaceX, Orbital, and to my knowledge every compny that has placed a payload in orbit had substantial government funding. In some cases the government funding was not specifically in return for the orbital launch, but was vital nonetheless. That is consistent with the original role of NASA, nt corporate welfare but priming the pump. I agree that the DOD's "cost-plus" approach to launch contracting really does give an incentive to contractors to keep costs high. </p><p>Hopefully SpaceX will be able to compete, but in the ommercial arena its principle competitors will be non-US carriers; Sea Launch, ILS, Arianespace, China, etc. </p><p>Finally I have seen no data to indicate that the pintle engine has any real cost adantages beyond the protoype stage. The traditional injector plate requires more machining but this isn't as much of an issue with computer aided manufacturing as it would be with hand fabrication. The SSME injector was very complex due to the staged combustion design and fabricated coaxial injectors which have to combine thee different propellant streams, LH2, LOX, and the turbopump exhaust, but this approach was dropped on the RS-68 in favor of the simpler gas-generator cycle, apparently without any significant loss in performance. </p><p>The pintle adds weight and length to the engine, and does not look easy to scale. I wouldn't be at all suprised if the next generation of Falcon has a planar injector plate. </p>
 
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dwightlooi

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>SpaceX, Orbital, and to my knowledge every compny that has placed a payload in orbit had substantial government funding. In some cases the government funding was not specifically in return for the orbital launch, but was vital nonetheless. That is consistent with the original role of NASA, nt corporate welfare but priming the pump. I agree that the DOD's "cost-plus" approach to launch contracting really does give an incentive to contractors to keep costs high. Hopefully SpaceX will be able to compete, but in the ommercial arena its principle competitors will be non-US carriers; Sea Launch, ILS, Arianespace, China, etc. Finally I have seen no data to indicate that the pintle engine has any real cost adantages beyond the protoype stage. The traditional injector plate requires more machining but this isn't as much of an issue with computer aided manufacturing as it would be with hand fabrication. The SSME injector was very complex due to the staged combustion design and fabricated coaxial injectors which have to combine thee different propellant streams, LH2, LOX, and the turbopump exhaust, but this approach was dropped on the RS-68 in favor of the simpler gas-generator cycle, apparently without any significant loss in performance. The pintle adds weight and length to the engine, and does not look easy to scale. I wouldn't be at all suprised if the next generation of Falcon has a planar injector plate. <br /> Posted by vulture4</DIV></p><p>Three things:-</p><p>(1) The pintle engine is actually easier to scale. The reason being that the nozzle and chamber geometries scale very well across a factor of ten times its orignal size with little deviations on combustion stability. You are also scale two coaxial areas instead of a showerhead full of them. The pintel engine is also more throttlable with a with a thrust range from 10~100% possible on say the lunar module engine. Typical shower head style engines are only throttlable from about 60~100%. </p><p>(2) The performance advantage of showerhead designs is not worth the design cost, recurring cost and reduced scalability. You lose about 3~4 seconds of IpSec (if that). No problem, you simpy build a 10% larger rocket to lift the same payload and waste a but more fuel doing it. Fuel costs and a slightly larger vehicle is not the cost drivers -- complexity, extreme weight reduction and going for the last few bits of performance are. Easy to design, cheap to build, less finicky to fly and easy to make derivative designs from -- those are the worthwhile goals, not bragging rights about my payload fraction being a but better than yours.</p><p>(3) In fact, I completely agree with the space X approach of a low performance, simple, pressure fed upper stage over a high performance hydrogen upper stage which performance driven designs tend to go for. A pressure fed 1st stage will be great to, although the weight penalty will also be tremendous and more importantly the low chamber pressures and thrust may make it unfeasible. </p><p>&nbsp;</p>
 
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docm

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<p>IIRC TRW worked on their Low Cost Pintle Engine and had some good results but NASA wasn't interested. Sounds familiar. SpX picked up the ball and ran with it. </p><p>My assumption re: the real weakness of pintles (someone correct me if I'm wrong): high temps at the throat due to the complex heat flow, but regen seems to solve that in the later Merlins (it caused problems in the original albative Merlin). In the Kestrel (also ablative) this is likely the cause of that 'hot spot' you see in the videos, but if you build for it and the engine is small.....</p> <div class="Discussion_UserSignature"> </div>
 
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Boris_Badenov

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<p><font size="2"><font size="2">Congradulations to SpaceX</font></font></p><p><font size="2">On behalf of myself and all of us at Bigelow Aerospace, I would like to congratulate Elon Musk and the entire SpaceX team on the successful launch of the Falcon 1. There is no field more relentlessly unforgiving than rocketry and to achieve success as quickly as SpaceX has is truly a momentous accomplishment. With our own Genesis I and II currently in orbit, the suborbital flights of Scaled Composite's SpaceShipOne, and now the successful launch of Falcon 1, we are clearly seeing the dawn of a new era. SpaceX's singular achievement has brought us closer to realizing the shared vision of a robust, private sector driven space marketplace whose fruits all of humanity can enjoy. This launch may have been one small step for SpaceX, but it's a giant leap for the entrepreneurial space industry."<br /><br />- Robert T. Bigelow</font> </p> <div class="Discussion_UserSignature"> <font color="#993300"><span class="body"><font size="2" color="#3366ff"><div align="center">. </div><div align="center">Never roll in the mud with a pig. You'll both get dirty & the pig likes it.</div></font></span></font> </div>
 
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dwightlooi

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>IIRC TRW worked on their Low Cost Pintle Engine and had some good results but NASA wasn't interested. Sounds familiar. SpX picked up the ball and ran with it. My assumption re: the real weakness of pintles (someone correct me if I'm wrong): high temps at the throat due to the complex heat flow, but regen seems to solve that in the later Merlins (it caused problems in the original albative Merlin). In the Kestrel (also ablative) this is likely the cause of that 'hot spot' you see in the videos, but if you build for it and the engine is small..... <br /> Posted by docm</DIV></p><p>Well, sort of, but not really. Throat temperature has a lot to do with chamber pressure too. Chamber pressure improves specific impulse. In general, higher chamber pressure equals more thrust for the same engine size and higher specific impulse (lbs of thrust per pound-sec of fuel used). The thing about high chamber pressures is that the engine has to be built to handle it, the chamber has to be stronger, the pumps bigger, the nozzle heavier, etc. Consequentially, thrust to weight ratio may be no better, or worse, even if thrust to engine size ratio tends to be favorable.</p><p>Just to put the numbers out for our discussion the chamber pressures of the Merlin, the F-1 and the RD-180 are as follows:-</p><p>Merlin&nbsp; = ~890 psi (Gas Generator Cycle)</p><p>F-1 (Apollo/Saturn V) = ~1030 psi (Gas Generator Cycle)</p><p>RD-180 (Atlas V) = ~3770 psi (Staged Combustion)</p><p>With good weight and design discipline you can build an engine with just as good or better thrust to weight ratio even if the operating chamber pressure is lower. Again, for the three engines the T/W ratios are as follows:-</p><p>Merlin =&nbsp; 93:1</p><p>F-1 = 94:1</p><p>RD-180 = 79:1 </p><p>What's really important though is that thrust-to-weight, thrust-to-size and specific impulse should not be the design objective. The design objective should be to make a simple, reliable, robust and CHEAP launch vehicle. If performance improvements do not improve the dollar-per-pound to LEO quotion, then those performance improvements are worthless. </p><p>&nbsp;</p>
 
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dragon04

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<p>I was really stoked to see SpaceX get that rocket into space. Now I have a question that I'm not sure can be answered, but if t can, you people certainly are the ones to go to. Actually, this is going to be a few questions.</p><p>&nbsp;</p><p>1. Generally speaking, does getting a payload to orbit mean that "the major bugs are worked out" in regards to any lanuch vehicle?</p><p>2. How many successful launches must be made before a launcher's "reliability is proven"? Or is it a case that a launch vehicle is only as reliable as its last launch?</p><p>3. The Merlin engine has now successfully boosted a payload to space. How much confidence will that translate to the Falcon 9 launch vehicle considering that 9 Merlins have to be hooked together?</p><p>4. In layman's terms (if that's possible), what is unique or majorly different between the MErlin and any other rocket engine of its type? Meaning a RUssian or Boeing or WHoever engine that burns the same propellant type?</p><p>&nbsp;</p><p>&nbsp;</p><p>&nbsp;</p> <div class="Discussion_UserSignature"> <em>"2012.. Year of the Dragon!! Get on the Dragon Wagon!".</em> </div>
 
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Swampcat

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<p><font color="#008800"><strong>Flight 4 Launch Update</strong></font></p> <p>There's new video and some words about the next Falcon 1 flights.</p> <div class="Discussion_UserSignature"> <font size="3" color="#ff9900"><p><font size="1" color="#993300"><strong><em>------------------------------------------------------------------- </em></strong></font></p><p><font size="1" color="#993300"><strong><em>"I hold it that a little rebellion now and then is a good thing, and as necessary in the political world as storms in the physical. Unsuccessful rebellions, indeed, generally establish the encroachments on the rights of the people which have produced them. An observation of this truth should render honest republican governors so mild in their punishment of rebellions as not to discourage them too much. It is a medicine necessary for the sound health of government."</em></strong></font></p><p><font size="1" color="#993300"><strong>Thomas Jefferson</strong></font></p></font> </div>
 
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