SS2 propulsion

[jhoblik]

Do you have idea about SS2 propulsion? It will be same kind of engine or something what Airlaunch is going to use?

 

[holmec]

SS1 propulsion was a hybrid solid/liquid rocket motor. I believe SS2 will be the same.<br /><br />SpaceDev made the hybrid rocket, NASA had a study to look at it, and SpaceDev's Dreamchaser space ship will use a simular rocket.<br /><br />Here is some info from Scaled Composites<br />http://www.scaled.com/projects/tierone/info.htm <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>

 

[docm]

My reading is that it's a hard wax/paraffin hybrid using LOX as the oxydizer. Clean burning, cheap, easy to cast and 2-3x the thrust of a similar rubber/NOX hybrid as used in SS1. NASA tested such a hybrid at Ames ~2003.<br /> <div class="Discussion_UserSignature"> </div>

 

[barrykirk]

We are talking suborbital here. Even with a very low ISP which hybrids are known for. The fuel mass fraction is going to be fairly low because the total delta-v required is minimal.<br /><br />The fact that the SS2 is launched from high altitude helps even more.<br /><br />I'm certain that Mr. Rutan will abandon hybrid fuel should he attempt to build a vehicle that will reach LEO.

 

[lampblack]

<font color="yellow">My reading is that it's a hard wax/paraffin hybrid...</font><br /><br />Gives a whole new meaning to the phrase "candle power," eh? <img src="/images/icons/wink.gif" /> <div class="Discussion_UserSignature"> <font color="#0000ff"><strong>Just tell the truth and let the chips fall...</strong></font> </div>

 

[scottb50]

I'm certain that Mr. Rutan will abandon hybrid fuel should he attempt to build a vehicle that will reach LEO.<br /><br />Just like with the Shuttle there will be a need for low ISP, high thrust engines for the initial launch and hybrids add a level of safety as well as lower weight compared to conventional propellants. <div class="Discussion_UserSignature"> </div>

 

[holmec]

>My reading is that it's a hard wax/paraffin hybrid using LOX as the oxydizer. Clean burning, cheap, easy to cast and 2-3x the thrust of a similar rubber/NOX hybrid as used in SS1. NASA tested such a hybrid at Ames ~2003.<br /><br /><br />DocM<br /><<br /><br />LOX??? That would put a whole new level of complexity to the operation and cost as well. I highly doubt it will be cryonic gasses. Can you confirm this? <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>

 

[PistolPete]

It's not <i>that</i> complex. From what I understand LOX is only <i>mildly</i> cryogenic. It is a commonly used oxydizer and shouldn't add to much complexity to the system. Expecially when you calculate in the Isp benifits of using it. <div class="Discussion_UserSignature"> <p> </p><p><em>So, again we are defeated. This victory belongs to the farmers, not us.</em></p><p><strong>-Kambei Shimada from the movie Seven Samurai</strong></p> </div>

 

[mrmorris]

<font color="yellow">"... LOX is only mildly cryogenic."</font><br /><br />Isn't that sort of like being <i>slightly</i> pregnant? <img src="/images/icons/smile.gif" />

 

[propforce]

I understand they put LOX in every fighter jets as a part of the breathable air supply. So the Air Force is very comfortable in handling LOX. <div class="Discussion_UserSignature"> </div>

 

[barrykirk]

With the same amount of insulation. A given volume of LOX will experience a lot less boiloff than the same volume of LH2. An order of magnitude less boiloff.

 

[CalliArcale]

<blockquote><font class="small">In reply to:</font><hr /><p>Isn't that sort of like being slightly pregnant?<p><hr /></p></p></blockquote><br /><br />*grins* Well, I've just hit the third trimester of pregnancy myself, so I can say that it is actually true that there are levels of pregnancy. <img src="/images/icons/wink.gif" /> When the little blue line shows up on the test, you're slightly pregnant. (That is, unless you're one of the unlucky ones, you still feel fine, you fit in all your clothes, and you don't look like a beached whale.) By the third trimester, that ain't so anymore. By the third trimester, you're very pregnant. By the ninth month, phrases such as "heavily pregnant" and "extremely pregnant" apply. Your life is at this point defined by your pregnancy. Total strangers ask to touch your tummy, and even ask deeply personal questions like whether or not you plan to have an episiotomy. You can't get comfortable. Ever. You get kicked in odd portions of your internal anatomy right while you're trying to concentrate on a business meeting.<br /><br />Trust me on this. <img src="/images/icons/wink.gif" /> There is such a thing as slightly pregnant, as proven by the fact that *very* pregnant is a definite condition. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[propforce]

<blockquote><font class="small">In reply to:</font><hr /><p>Trust me on this. There is such a thing as slightly pregnant, as proven by the fact that *very* pregnant is a definite condition. <p><hr /></p></p></blockquote><br /><br />... AND... applying Calli's personal experience to project management...<br /><br />It takes one woman & 9 month of pregnancy to have a baby, but you can NOT substitute it with 9 women & only 1 month to have a baby !! <br /><br />Painful [pun-intended] lessons learned in project management. <div class="Discussion_UserSignature"> </div>

 

[docm]

<blockquote><font class="small">In reply to:</font><hr /><p>holmec said;<br /><br />LOX??? That would put a whole new level of complexity to the operation and cost as well. I highly doubt it will be cryonic gasses. Can you confirm this?<p><hr /></p></p></blockquote><br />Confirm, no. <b><i>Strongly suspect</i></b>, heck yes. This based on the patented work done at Stanford on paraffin/LOX hybrids. <br /><br />http://daily.stanford.edu/article/2005/2/1/rocketScientistsMakeCandleWaxIntoFuel<br /><br />http://news-service.stanford.edu/zmedia/Rocketwax.mov<br /><br /> <div class="Discussion_UserSignature"> </div>

 

[mrmorris]

<font color="yellow">"There is such a thing as slightly pregnant..."</font><br /><br />I have two daughters. Mind you I didn't have them <b>personally</b> but got 18 months worth of spectating. I was just amused at the wording 'mildly cryogenic' and that's the catchphrase it called to mind. As to the next person that asks about an episiotomy... hit them. Hit them hard. And for anyone that's interested -- use Dictionary.com -- it doesn't need to be defined here. Look it up at your own risk. If you absolutely can't resist looking it up -- you'll wish that you had afterward.

 

[PistolPete]

I just looked it up. Wow, sounds painfull. Mrmorris is right Calli, the next time someone asks you that question tell them to get it done to themselves. Male or female, it should have the same effect.<br /><br /><br />Yikes, and yikes again. <div class="Discussion_UserSignature"> <p> </p><p><em>So, again we are defeated. This victory belongs to the farmers, not us.</em></p><p><strong>-Kambei Shimada from the movie Seven Samurai</strong></p> </div>

 

[spacester]

My general impression over my years of googling is that when trade studies are done, the operational cost of LOX is rarely a show-stopper or even a major deciding factor. <br /><br />It's just simply way way easier to deal with than LH2. It's an industrial commodity, you can make it "out of thin air", the fittings work, the refrigeration systems are well proven, it's a big molecule.<br /><br />Compared to most of the fuels, it is wonderfully dense, so your tankage doesn't have to dominate the vehicle architecture.<br /><br />All this being just general impressions . . . but certainly my understanding is that we are looking at Parafin and LOX here. It's not exactly a new idea. <div class="Discussion_UserSignature"> </div>

 

[docm]

Let's not forget that tens of thousands of people carry therapeutic LOX tanks on their person every day, so it's not <i>that</i> dangerous. It's all in how well it's stowed and protected. <br /><br />Ex: http://www.puritanbennett.com/prod/Product.aspx?S1=OXY&S2=&id=32 <div class="Discussion_UserSignature"> </div>

 

[spacester]

Well I would hope that the on/off capability is all about establishing a flight regime where those emergency scenarios are benign to a high degree of certainty.<br /><br />(I can't believe I'm telling <i>you</i> about flight regimes! Half of what I know about airplanes is from you, lol) <div class="Discussion_UserSignature"> </div>

 

[ldyaidan]

Congrats, Callie! Best of wishes for your new little one. Mine are mostly grown, thank goodness! Watch out, tho, for aunts like me, who's primary job is to spoil them rotten, fill them full of sugar and caffiene, and send them home with the noisy toys that don't use batteries...<br /><br />Rae