Kerosene & LOX Limits

[tap_sa]

<font color="yellow">"That is not a problem, it could be an advantage. "</font><br /><br />Hydrogen boils at 20K, oxygen freezes at 54K. This makes it a problem.<br /><br /><font color="yellow">" The warmer the Hydrogen, and the higher the pressure, the better"</font><br /><br />Hydrogen is usually stored already at the boiling point. There's continuous boiling going on inside the tank but the insulation keeps it at manageable levels. IIRC just before liftoff the tank pressure is raised to 'flight level', which helps temporarily to minimize the boiling.<br /><br />From hydrogen's point of view even frozen oxygen can be 'hot' and LOX is <i>burning</i> hot. Uncontrolled exposure to LOX temperatures may cause violent, almost explosive boiling. Hydrogen's density is low enough even as pure liquid so we really don't want to pump anything but liquids. And cavitation would break a turbopump anyway.<br /><br /><font color="yellow">"The colder and denser the Oxygen the better"</font><br /><br />Sure but you'd have to be extra careful not to freeze the LOX. Unshielded LOX line through liquid hydrogen tank would freeze solid in no time. And before that chunks of frozen oxygen might come loose, get sucked up to the pump breaking it and/or clogging up the injector holes.

 

[scottb50]

The idea is to get the Hydrogen to the highest possible pressure before it combines with the Oxygen and the Oxygen as dense as possible before it enters the combustion chamber.<br /><br />By rapidly raising the temperature of the Hydrogen and lowering that of the Oxygen you need smaller turbopumps and have a simpler engine. With the flow rates on a Launcher you wouldn't have to worry about the Oxygen freezing either. I would think solid Oxygen would be like snow anyway. The problem is a pump going from liquid to gas, not that you can't pump a gas as well as you can a liquid.<br /><br /> <div class="Discussion_UserSignature"> </div>

 

[killium]

"As Von Braun envisioned with the Nova class rocket, you just keep making the kerosene/LOX stages bigger, till they lift the load you want. "<br /><br />Why are they always thinking about ONE big/bigger vehicle ? Why not use already, smaller vehicule and send a couple, so you assemble a relatively low cost/not so big rokect in orbit ? It shouldn't be too complicated to keep the fuel in orbit until used. At last, you send the crew and they quit the orbit....<br /><br />Imagine 20 shuttle mission each bringing up a piece of a delta IV class rocket, for example. A rocket of this class, already in orbit, should be able to go to mars relatively easily (i didn't make any calculations, the example used is just for showing the concept).<br /><br />Would this be more costly than desinging a new, heavy (i mean very heavy) lift booster ?<br /><br /> <div class="Discussion_UserSignature"> </div>

 

[dobbins]

Time spent hauling up the ISS a little bit at each launch is one of the primary reasons it's cost has spiraled out of control. If we still had the Saturn V when it was being planed the whole thing could have been launched with 4 or 5 flights. Instead we are looking at 17 of the last 19 Shuttle flights on top of earlier Shuttle construction flights to partially accomplish something that could have been done a lot faster and for a lot less money with a heavy lift launcher.<br /><br />

 

[killium]

I agree but, I would really love to see real calculations about what is more costly: Launching 5 Saturn V or designing, testing, and launching 1 big rocket equivalent in regards to performance and capabilities to 5 Saturn V ? <div class="Discussion_UserSignature"> </div>

 

[pmn1]

There is an article by Stephen S Pietrobon (Small World Communications) in the May/June 1999 Journal of the British Interplanetary Society about replacing the SRB’s with LRB’s<br /><br /><font color="yellow">The use of high-density hydrogen peroxide/kerosene liquid rocket boosters for the Space Shuttle is investigated as a replacement for the existing SRB’s. It is shown that H2O2/Kerosine outperforms solids, LOX/Kerosene and LOX/LH2 as a general booster propellant due to its high density and moderate exhaust speed. With the same propellant mass and size as that of the current SRB’s, computer simulations indicate payload mass can be increased by a third from 24,950kg to 33,140kg for a 28.45°, 203.7km circular orbit.</font><br /><br />AndyMc on Nasaspaceflight.com has found the full PDF..<br /><br />Hi,<br /><br />Just googled, and found the article you mention is availabe as a pdf: http://www.sworld.com.au/steven/pub/lrb.pdf<br /><br />His site may also have some more things of interest: http://www.sworld.com.au/steven/ <div class="Discussion_UserSignature"> </div>

 

[vogon13]

If your one big vehicle is Orion the launch costs can go down to pennies per pound.<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>

 

[dobbins]

" If your one big vehicle is Orion the launch costs can go down to pennies per pound."<br /><br />Not when the other costs are figured in. Things like thousands of lawsuits, payment for EMP and health damages, economic boycotts against the nation that launched the thing, and declarations of war by nations that are upset about it's fallout raining down on them. That would drive the costs to many times those of the Shuttle, currently the most expensive way to put a payload into space.<br /><br />

 

[tap_sa]

Orion is for true settlers who don't plan to return, ever <img src="/images/icons/wink.gif" />

 

[dobbins]

Return? They won't get anywhere. If the lawsuits don't stop them they will fall victim to a lynch mob or a preemptive military strike.<br /><br />Forget Orion, political realities make it as much pie in the sky dreaming as warp drive star ships.<br /><br />

 

[lampblack]

<font color="yellow">Orion is for true settlers who don't plan to return, ever <img src="/images/icons/wink.gif" /> </font><br /><br />Sort of like passing gas on your way out of a crowded room... not exactly the most polite thing to do. <img src="/images/icons/wink.gif" /><br /> <div class="Discussion_UserSignature"> <font color="#0000ff"><strong>Just tell the truth and let the chips fall...</strong></font> </div>