ET-less SDV with clustered SRB's?

[yummylicious2323]

Hello everybody! I'm new to this forum. Here's my little pitch; it may be naive (sorry! i'm a bio-engineering student, not aeronautical or mechanical), or perhaps it will be worth your while.<br /><br />It seems that most heavy lift SDV concepts revolve around a modified ET with twin strap on boosters, be they 4 segments, five, solid, liquid, flyback, whatever.<br />But they are always limited to only two booster, the main reason being that the ET is structurally unable to handle the thrust load of anything more than the twin flanking rocket. But what if we get rid of the ET altogether and instead array several SRB's (3? 6? 8? i don't know how many) around a lightweight central trusswork? A second stage with the payload can be mounted atop this assembly.

 

[rogers_buck]

The SRBs are pretty heavy so you wouldn't want them along as second stage dead weight. They don't burn all that long either, so you would need them along as seconds stage dead weight. Too many burning at once and your pulling too many Gs. I don't know how all those trade-offs "stack up" . The SSMEs burn for a long time after the SRBs burn out.

 

[yummylicious2323]

I was imagining that the second stage would be typical, liquid fueled. Since the vehicle would be unmanned, it can withstand greater G loads. And lastly, the SRB propellent can be reformulated for longer burns.

 

[SpaceKiwi]

I'm not sure where you are going with this? It's an alternate approach to be sure but, if your goal is to put on the order of 100-120 tonnes into orbit, the config using the ET is likely to deliver. Remember, foam shedding is not a problem for the proposed SDHL vehicle as it is unmanned. Therefore, no real need to get rid of the ET to accomodate more SRB's as 2 five segment SRB's and a SSME pod at the base of the ET will get the job done. <div class="Discussion_UserSignature"> <p><em><font size="2" color="#ff0000">Who is this superhero?  Henry, the mild-mannered janitor ... could be!</font></em></p><p><em><font size="2">-------------------------------------------------------------------------------------------</font></em></p><p><font size="5">Bring Back The Black!</font></p> </div>

 

[spacester]

Welcome to sdc, yummy!<br /><br />I think it's a good vehicle concept. If the economics of the SRBs are vastly superior to ET vehicles, this could be a concept bringing CATS (Cheap Access to Space).<br /><br />Cost of propellant is low of course, but what about the cost of propellant procedures? IOW how cheap could a SDHLV get if you got rid of the whole first stage cryogenics operations?<br /><br />The development costs of the SRB are already mostly paid for, so if NASA politics allowed it to happen, this configuration could qualify as a BDB delivering CATS. A Big Dumb Booster with development costs mostly paid for is a recipe for a space faring society.<br /><br />IOW if you could build this vehicle and fly it without a standing army, it could be pretty cheap. Put a kerosene / LOX second stage on it and operations costs would go down even more. You could use the second stage on orbit (space tug, interplanetary boosters) without dealing with liquid hydrogen, just the LOX.<br /> <div class="Discussion_UserSignature"> </div>