Idea for a Cheap, Reusable, Horizontally Launched, Single Stage to Sub-orbit.

[Stewie_Griffin]

<p>So I was thinking, if you made a kind of hybrid airship/spaceplane it would be cheaper than the designs by current private spaceflight companies (Spaceship 1/2 and Lynx). &nbsp;It would have a giant delta wing that would be a giant helium balloon with a frame between two layers of some kind of fabric. &nbsp;Mounted below the wing would be a basic rocket engine and fuel tanks as well as a cheap small jet engine, landing gear, and a payload bay. &nbsp;The rocket engine would run off LOX/Kerosene and the jet engine would run off Kerosene so the design would only need two fuel tanks.</p><p>The helium ballon would be big enough that without any payload, the spaceplane &nbsp;could float up off the ground. &nbsp;It would take off horizontally using the small jet engine and would continue to climb like that until it was at an altitude where the jet would no longer provide enough thrust. &nbsp;At this altitude it would engage the rocket engine and shoot up to space.</p><p>The advantages of this design&nbsp;would be that it would not need to carry a lot of rocket fuel, and it would be light enough that it's going into space and the re-entry could be slower than conventional designs. &nbsp;The balloon/wing would also provide massive aerobraking on re-entry and when it goes in for a landing it would have no fuel so it would be way lighter than air and it's landing could be at a very slow speed. &nbsp;The main disadvantage that I can think of is finding a fabric for the balloon/wing that could withstand the heat and the high speeds.&nbsp;</p><p>So I was just posting this because I wanted to see what other people thought of my idea, I'm not an expert on aerospace engineering or anything so if there's a major design flaw with this idea please tell me. &nbsp;Also please tell me if you have any ideas that might make it better or something that the fabric could be made of.</p><p>Thanks!&nbsp;</p> <div class="Discussion_UserSignature"> </div>

 

[Crossover_Maniac]

The problem is that it takes such a high change in velocity to achieve orbital velocity (17000 mph plus an additional 3400 mph to counter losses in gravity and drag) that SSTO's empty weight would have to be next to nothing (92% fuel, 8% structure and payload) or use something with more energetic (like nuclear-power) or use an air-breathing engine (scramjet).&nbsp; None of which are cheap and will cost more in the long run than going two-stage, which is simplier, cheaper, and more robust.&nbsp; The only thing I can think of that might pass muster without some serious technological hurtle would be a duel mode ducted-rocket that draws some of its oxider from the atmosphere. <div class="Discussion_UserSignature"> Feel the Hope-nosis </div>

 

[BrianSlee]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>So I was thinking, if you made a kind of hybrid airship/spaceplane it would be cheaper than the designs by current private spaceflight companies (Spaceship 1/2 and Lynx). &nbsp;It would have a giant delta wing that would be a giant helium balloon with a frame between two layers of some kind of fabric. &nbsp;Mounted below the wing would be a basic rocket engine and fuel tanks as well as a cheap small jet engine, landing gear, and a payload bay. &nbsp;The rocket engine would run off LOX/Kerosene and the jet engine would run off Kerosene so the design would only need two fuel tanks.The helium ballon would be big enough that without any payload, the spaceplane &nbsp;could float up off the ground. &nbsp;It would take off horizontally using the small jet engine and would continue to climb like that until it was at an altitude where the jet would no longer provide enough thrust. &nbsp;At this altitude it would engage the rocket engine and shoot up to space.The advantages of this design&nbsp;would be that it would not need to carry a lot of rocket fuel, and it would be light enough that it's going into space and the re-entry could be slower than conventional designs. &nbsp;The balloon/wing would also provide massive aerobraking on re-entry and when it goes in for a landing it would have no fuel so it would be way lighter than air and it's landing could be at a very slow speed. &nbsp;The main disadvantage that I can think of is finding a fabric for the balloon/wing that could withstand the heat and the high speeds.&nbsp;So I was just posting this because I wanted to see what other people thought of my idea, I'm not an expert on aerospace engineering or anything so if there's a major design flaw with this idea please tell me. &nbsp;Also please tell me if you have any ideas that might make it better or something that the fabric could be made of.Thanks!&nbsp; <br />Posted by Stewie_Griffin</DIV></p><p>Check this site out.&nbsp; It has already been patented<br />www.escape-velocity.biz</p> <div class="Discussion_UserSignature"> <p> </p><p>"I am therefore I think" </p><p>"The only thing "I HAVE TO DO!!" is die, in everything else I have freewill" Brian P. Slee</p> </div>

 

[chanimanga]

<p>I believe that with the number of minds thinking about this problem for the last 60 years or so, every idea that could have been though up, has been though up. However, theres a large distance between having the idea and having the engineering and technology to achieve them in reality. Far better to focus on doing what we can do better and cheaper than we used to be able to do it.</p><p>&nbsp;Now.. where did i put my anti-gravity machine </p> <div class="Discussion_UserSignature"> <p> </p><p> </p><p>++++++++++++++++++++++++++++++++++++++++++++</p><p> </p><p>Join a true space community TheAlphaOrbital.com</p> </div>

 

[Stewie_Griffin]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>I believe that with the number of minds thinking about this problem for the last 60 years or so, every idea that could have been though up, has been though up. However, theres a large distance between having the idea and having the engineering and technology to achieve them in reality. Far better to focus on doing what we can do better and cheaper than we used to be able to do it.&nbsp;Now.. where did i put my anti-gravity machine <br /> Posted by chanimanga</DIV></p><p>&nbsp;</p><p>except if we never tried anything new we would be without technology.</p> <div class="Discussion_UserSignature"> </div>

 

[scottb50]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>So I was thinking, if you made a kind of hybrid airship/spaceplane it would be cheaper than the designs by current private spaceflight companies (Spaceship 1/2 and Lynx). &nbsp;It would have a giant delta wing that would be a giant helium balloon with a frame between two layers of some kind of fabric. &nbsp;Mounted below the wing would be a basic rocket engine and fuel tanks as well as a cheap small jet engine, landing gear, and a payload bay. &nbsp;The rocket engine would run off LOX/Kerosene and the jet engine would run off Kerosene so the design would only need two fuel tanks.The helium ballon would be big enough that without any payload, the spaceplane &nbsp;could float up off the ground. &nbsp;It would take off horizontally using the small jet engine and would continue to climb like that until it was at an altitude where the jet would no longer provide enough thrust. &nbsp;At this altitude it would engage the rocket engine and shoot up to space.The advantages of this design&nbsp;would be that it would not need to carry a lot of rocket fuel, and it would be light enough that it's going into space and the re-entry could be slower than conventional designs. &nbsp;The balloon/wing would also provide massive aerobraking on re-entry and when it goes in for a landing it would have no fuel so it would be way lighter than air and it's landing could be at a very slow speed. &nbsp;The main disadvantage that I can think of is finding a fabric for the balloon/wing that could withstand the heat and the high speeds.&nbsp;So I was just posting this because I wanted to see what other people thought of my idea, I'm not an expert on aerospace engineering or anything so if there's a major design flaw with this idea please tell me. &nbsp;Also please tell me if you have any ideas that might make it better or something that the fabric could be made of.Thanks!&nbsp; <br /> Posted by Stewie_Griffin</DIV></p><p>The problems are as pointed out in the intervening posts, the biggest problem is achieving the necessary velocity to reach orbit and even starting from 50-60,000 feet, with limited velocity doesn't do very much. If you look at the Shuttle it is basically a TSTO design, the SRB first stage accelerates the Shuttle/ET to a point where the mass is low enough for the Shuttle engines to keep acceleration going. At lift off the SRB's provide more then 5 million pounds of thrust while the SSME's provide a little more then 1 million pounds, since the whole thing weighs roughly 4.4 million pounds at liftoff the SSME's carry some of their and their propellant weight. What they most importantly do is reduce the weight of the Shuttle/ET to a point that they can provide enough thrust to keep accelerating after the SRB's are dumped.</p><p>Once the SRB's are dropped the SSME's have sufficient power and propellant to continue to orbit, in your scenerio, once a balloon, or a White Knight carrier drops the orbiter it still needs a lot of thrust to get to orbit. The Pegasus is a good example. It needs an L-1011 category aircraft to get it to alitude and three stages of rocket motors to get roughly 1,000 pounds to orbit. A SSTO vehicle would not work in either of these cases and a way to make it work has not been found, different areas of the atmosphere and velocities require different engines and those not in use are dead weight.</p><p>That's why a true TSTO design makes the most sense, a first stage that releases an upper stage, at near Shuttle acceleration,&nbsp; and flies back for refurbishment and re-use. An upper stage that uses first stage carried propellant, that assists in the launch, and internal propellant to continue to orbit. Basically the first stage would be SRB's and an ET with wings and turbofan engines for return with an externally mounted upper stage with SSME's and it's own propellant. The payload could be a re-entry vehicle or strickly orbital payload. </p> <div class="Discussion_UserSignature"> </div>

 

[Stewie_Griffin]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>The problems are as pointed out in the intervening posts, the biggest problem is achieving the necessary velocity to reach orbit and even starting from 50-60,000 feet, with limited velocity doesn't do very much. If you look at the Shuttle it is basically a TSTO design, the SRB first stage accelerates the Shuttle/ET to a point where the mass is low enough for the Shuttle engines to keep acceleration going. At lift off the SRB's provide more then 5 million pounds of thrust while the SSME's provide a little more then 1 million pounds, since the whole thing weighs roughly 4.4 million pounds at liftoff the SSME's carry some of their and their propellant weight. What they most importantly do is reduce the weight of the Shuttle/ET to a point that they can provide enough thrust to keep accelerating after the SRB's are dumped.Once the SRB's are dropped the SSME's have sufficient power and propellant to continue to orbit, in your scenerio, once a balloon, or a White Knight carrier drops the orbiter it still needs a lot of thrust to get to orbit. The Pegasus is a good example. It needs an L-1011 category aircraft to get it to alitude and three stages of rocket motors to get roughly 1,000 pounds to orbit. A SSTO vehicle would not work in either of these cases and a way to make it work has not been found, different areas of the atmosphere and velocities require different engines and those not in use are dead weight.That's why a true TSTO design makes the most sense, a first stage that releases an upper stage, at near Shuttle acceleration,&nbsp; and flies back for refurbishment and re-use. An upper stage that uses first stage carried propellant, that assists in the launch, and internal propellant to continue to orbit. Basically the first stage would be SRB's and an ET with wings and turbofan engines for return with an externally mounted upper stage with SSME's and it's own propellant. The payload could be a re-entry vehicle or strickly orbital payload. <br /> Posted by scottb50</DIV></p><p>&nbsp;</p><p>What you said mostly makes sense, but actually if you have an aerospike instead of a bell shape for your rocket engine it works better at all altitudes.</p><p>&nbsp;</p><p>http://en.wikipedia.org/wiki/Aerospike_engine</p> <div class="Discussion_UserSignature"> </div>

 

[scottb50]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>&nbsp;What you said mostly makes sense, but actually if you have an aerospike instead of a bell shape for your rocket engine it works better at all altitudes.&nbsp;http://en.wikipedia.org/wiki/Aerospike_engine <br /> Posted by Stewie_Griffin</DIV></p><p>That might very well be true. The problem is they don't exist on a scale usable for what we are talking about. I would rather use existing, proven, hardware to allow rapid development and then develop a market that could then allow next generation design.The&nbsp; biggest problem is getting over the initial hurdle, once you have a viable system it's capabilities will lead to demand for more capable and economical follow-ons. Sort of like "get your foot in the door."</p> <div class="Discussion_UserSignature"> </div>