How much further can rocket technology advance?

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grooble

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Will it ever be possible to have $600/lb or less to LEO? How much improvement can we expect from rocket engines over the next few decades, or the structure itself? And will it be possible to have rockets that can launch in bad weather?<br /><br />
 
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nexium

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CNT = carbon nano tubes may be used soon for parts of the boosters, rockets pay load etc. This has potential to halve the cost of a kilogram to orbit. Replacing oxygen with florine will shave some off the cost if the corrosion oroblems are solved. Neil
 
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tap_sa

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<font color="yellow">"Replacing oxygen with florine will shave some off the cost if the corrosion oroblems are solved. "</font><br /><br />Not likely. Both of you seem to mix cost efficiency with technical efficiency. For instance fluorine may be the most efficient oxidizer, but it gives only 10-20% extra performance compared to oxygen while costs at least an order of magnitude more, not to mention the technical difficulties handling it. And it may not be such a good idea to pump great amounts of fluorides into stratosphere.<br /><br />I do hope CNTs become cheap and strong enough to make the tank weight penalty in pressure feeding go away.
 
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rocketman5000

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The real hurdle is the amount of bureaucracy required to launch a vehicle and the low demand. The hurdle to cheap space launches is low cost. With higher demand the cost of launches would come down. I don't believe that cheap flight must be reusuable at least at first. It would be a very nice, (and romantic) if it went that direction eventually.
 
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unlearningthemistakes

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<img src="/images/icons/rolleyes.gif" /><br />ehrr...<br /><br />there was this <i>apparent</i> study that says sweet potato can be used to fuel space rockets.... <div class="Discussion_UserSignature"> <p>pain is inevitable</p><p>suffering is optional </p> </div>
 
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unlearningthemistakes

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anyone is free to stab this one... <div class="Discussion_UserSignature"> <p>pain is inevitable</p><p>suffering is optional </p> </div>
 
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micro10

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You would be suprised what you can do with Electro- energy and micro-energy.
 
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drwayne

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FLOX isn't *as* much of a problem as pure Flourine - I have seen some proposals to use it - though I have ideas of what I am going to do with my lottery winnings too. <img src="/images/icons/wink.gif" /><br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>
 
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rocketman5000

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That would be a very nice idea indeed. It would allow a SSTO that looks closer to an airplane. With an ISP of 3000 it would allow an initial mass fraction that was almost 75% of that placed in orbit.
 
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mikejz

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Lower costs has nothing to do with rocket technology, it has to do with better supply chain management and lower production costs. Period.
 
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mlorrey

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<blockquote><font class="small">In reply to:</font><hr /><p>"Replacing oxygen with florine will shave some off the cost if the corrosion oroblems are solved. " <br /><br />Not likely. Both of you seem to mix cost efficiency with technical efficiency. For instance fluorine may be the most efficient oxidizer, but it gives only 10-20% extra performance compared to oxygen while costs at least an order of magnitude more, not to mention the technical difficulties handling it. And it may not be such a good idea to pump great amounts of fluorides into stratosphere. <br /><br />I do hope CNTs become cheap and strong enough to make the tank weight penalty in pressure feeding go away.<p><hr /></p></p></blockquote><br /><br />The cost of fuel is a negligible percent of the total cost of launching today. The best way to reduce launch costs are to eliminate the standing army. NASA's 10,000 man army to maintian four vehicles and a few launches a year is incredibly uneconomic.<br /><br />$600/lb is about twice the cost of fuelling the space shuttle. Everything between there and $20k/lb is manpower, mismanagement, TPS, SSME, and SRB maintenance.<br /><br />There are two schools of thought for solving the problem:<br />a) big dumb booster: expendable simple boosters have a limit of about $2k/lb. Making one or more stages reusable, but still simply designed, could drop the cost/lb down to maybe the $600 level, but no less.<br />b) high performance RLV: GTX, NASP, Blackhorse, etc. but using high density fuels. Boron slurried Kerosene, for example.
 
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nacnud

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There is a third option, medium dumb reuseable rocket a la SpaceX.
 
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larrison

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I think the question was about rocket technology advancement generally in which I think were close to the ceiling (pardon the pun) for rocket technology.<br />I do believe that better management and use of materials can greatly reduce cost. Case in point about the same time Burt Rutan was winning the x-prize I read about a Swiss team sending a rocket up 70 miles to do atmospheric test at a cost of 100 million dollars. I believe Rutans estimated cost was about 10 million dollars. More than likely the Swiss could have paid Rutan to preform the experiments and saved 80 million dollars.
 
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scottb50

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I would think with the knowledge gained by Shuttle an updated SSME could be a pretty reliable engine. <div class="Discussion_UserSignature"> </div>
 
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mikejz

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Last I checked none have failed, so how do you define 'reliable'?
 
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scottb50

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That would be a good start. I think a couple have had problems of one kind or another.<br /><br />Even so they make a good starting point, keep what works and change what doesn't, or could be improved, like the combustion chamber design.<br /><br />I'd be more than happy for a few SSME's off the shelf, if it proved the need for the newer engines. <div class="Discussion_UserSignature"> </div>
 
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rocketman5000

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I think you need both schools of thought. like you said the difference in fuel cost is maintenance etc. Building a high performance RLV would be stupid if the supply and maintenace structure wasn't mastered. It would probably endup costing more. therefore a good interm to the RLV would be to create a big dumb booster. You could use the DBB to learn how to master the supply chain. <br /><br /><br />On a different note does anyone know how many people it takes to keep an airliner flying. It would be an interesting comparison.
 
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vogon13

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I have a stat from F-14 experience. A Tomcat absorbs roughly 40 hours of maintenance for every hour it flies.<br /><br />Sorry I don't recall commercial airliner stats, but Boeing and Airbus make that parameter's reduction over the years to be a selling point for their aircraft.<br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>
 
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tap_sa

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<font color="yellow">"The cost of fuel is a negligible percent of the total cost of launching today. The best way to reduce launch costs are to eliminate the standing army."</font><br /><br />Very true. But when you reduce the standing army, fuel costs aren't no longer negligible. Also propellant change from ordinary LOX/RP-1 etc to the exotic stuffs will skyrocket propellant costs.<br /><br /><font color="yellow">"Boron slurried Kerosene, for example."</font><br /><br />Pure elemental boron costs several dollars per <i>gram</i>.
 
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mlorrey

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<blockquote><font class="small">In reply to:</font><hr /><p>I have a stat from F-14 experience. A Tomcat absorbs roughly 40 hours of maintenance for every hour it flies. <br /><br />Sorry I don't recall commercial airliner stats, but Boeing and Airbus make that parameter's reduction over the years to be a selling point for their aircraft. <p><hr /></p></p></blockquote><br /><br />40 hours is pretty standard for most military aircraft, though the F-22 is supposed to be significantly better. Most man-hours per flight-hour for airliners is marketing, ticket sales, baggage handling, which the military generally doesn't deal with unless you look at man-hour numbers for the military transports.<br /><br />Still, even if you count 100-200 man-hours per flight hour, that is several magnitudes less than the 40,000 man-hours per flight hour of the Space Shuttle.<br /><br />As for rocket technology advancing, it advances all the time, it's just that nobody ever actually builds many of those advancements (X-33, 34, 37, 43, etc) into vehicles usable for passengers or cargo. Government is cheap and shouldn't be in the business to begin with, while the major contractors are always looking for free money from uncle sugar, and scaring away VCs with vague claims and empty promises.<br />
 
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mlorrey

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SSME's have avoided failures mostly (one did fail on a launch, but they made it to orbit burning longer on the other two engines) because they get totally rebuilt after each flight. A truly reliable engine should not need a major phase rebuilding for at least a few hundred hours of operation. The new COBRA design seems to be of this sort, or at least a step in that direction.
 
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mlorrey

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<blockquote><font class="small">In reply to:</font><hr /><p>"The cost of fuel is a negligible percent of the total cost of launching today. The best way to reduce launch costs are to eliminate the standing army." <br /><br />Very true. But when you reduce the standing army, fuel costs aren't no longer negligible. Also propellant change from ordinary LOX/RP-1 etc to the exotic stuffs will skyrocket propellant costs. <br /><br />"Boron slurried Kerosene, for example." <br /><br />Pure elemental boron costs several dollars per gram. <br /><br /><p><hr /></p></p></blockquote><br /><br />Why does NASA need to be its own fuel company? Subcontract it out to a chemical firm.<br /><br />Methyacetylene, which provides 25% more payload in orbit than RP-1, and 2.5 times more than LH2 (for an equal volume of fuel) is merely a slightly distilled form of common welders MAPP gas, which runs about $6/kg in bulk.<br /><br />Cyclopropane, also another 'exotic' of comparable performance to MA, is similarly cheap when bought on the open market.<br /><br />Liquid oxygen is considered a waste product by the chemical industry, and generally charges the costs of transportation, storage, etc plus distributors markup (and they have a hefty markup if you are a mom and pop user).<br /><br />I know these are facts, I'm in the welding and plasma cutting business.<br /><br />And, no, boron doesn't cost that much per gram, its about $10/kg. It doesn't need to be perfectly pure, this isn't subatomic physics we are dealing in here, this is hot rodding. 5% boron slurry in kerosene gives a 107 sec boost over plain RP-1.<br /><br />What that means, even if your 'pure atomic boron' were necessary, that for every 19 kg of RP-1 (at typically $5-10/kg, at worst), you put in one kg of boron, your fuel cost per kg has gone up two to three times at worst, more like 10-20% in reality, while your launcher retains the volumetric energy density of kerosene while gaining the high Isp of LH2 without the vehicle size problems. The size of the payload
 
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rocketman5000

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I think that to make a low maintenace rocket engine that is still highly reliable you will have to eliminate the highly complex turbopumps. and have either replacable combustion chambers and nozzles or chambers that do not need constant polishing. <br /><br />As mentioned earlier new materials coming out including CNT could allow pressurized fuel systems that work at much higher temperatures <br /><br />Does using boron doped kerosene require any modifications to the rocket motor?
 
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