Would the X-33 have worked as a 2-stage to orbit vehicle?

[dwightlooi]

The X-33 (and the follow up Venture Star) failed largely because it was technically unfeasible to build the vehicles with the kind of fuel fraction needed to be a single stage to orbit system. They tried to lighten the vehicle excessively and this led to cracking of the fuel tanks and a futile search for suitable heat shield material that is light enough. Even if funding was not pulled and they did fix the problems, it is doubtful that the X-33 would be able to reach orbital velocities -- even without a payload. Basically a 92% fuel fraction is simply unattainable in a vehicle that is to survive re-entry, and bring everything back.<br /><br />Nonetheless, the Linear Aerospike motor is largely a success. And if the vehicle is allowed to be heavier, it can be a lot more robust and feasible. I have always wondered if the system would work if they stop insisting that it be SSTO vehicle. What if they bolt a bundle of four 4 SRB cans side by side to the tail end of that thing? The SRBs will get it to 30km altitude and Mach 2.5. The vehicle then proceed with it's hydrogen aerospike engine. Would it have worked?

 

[spacefire]

to keep is similar in shape, it would have probably ahd to carry the second stage internally. <br />Having to carry a second stage might reduce the payload that gets to LEO. <div class="Discussion_UserSignature"> <p>http://asteroid-invasion.blogspot.com</p><p>http://www.solvengineer.com/asteroid-invasion.html </p><p> </p> </div>

 

[spacefire]

sorry-was thinking about a Vstar derivative. <div class="Discussion_UserSignature"> <p>http://asteroid-invasion.blogspot.com</p><p>http://www.solvengineer.com/asteroid-invasion.html </p><p> </p> </div>

 

[dwightlooi]

What I mean is would it have worked IF the X-33 or Venture star is the upper stage. The first stage at being four SRBs bundled side by side as a unit and stuck up the back of the vehicle. At lift off the SRBs will fire and provide 100% of the thrust. The SRBs burn out at a relatively low altitude and speed (say 30km and Mach 2.5). The X-33 or Venture star then continue the journey and the expended SRBs are parachuted down, recovered an reused.<br /><br />In other words, my question is... Would the X-33 or Venture have been likely of reaching orbital velocity if it was launched at 30km at with Mach 2.5 of veritcal velocity instead of being expected to lift off the ground at 0km/h?

 

[gunsandrockets]

"Would it [X-33] have worked [as RLV 2nd stage]?<br /><br />Possibly. Check out the Lockheed 'Starclipper' from 1966 and the 'Starclipper light' from 1968.<br /><br />http://www.astronautix.com/lvs/staipper.htm<br /><br />http://www.astronautix.com/lvs/stalight.htm<br /><br />The lineage to the X-33 and Venturestar seem clear, as the Starclipper even uses linear aerospike engines. Unlike the failed SSTO vehicle the Starclippers are stage and a half vehicles with expendable drop tanks.