Gemini: We can rebuild it, we have the technology

[rancamp]

Ok, I've finished the thread. Good stuff but a few comments.<br /><br />mrmorris:<br /> />I really like the parafoil, and I'd like to incorporate it<br /> />into the system.<br /><br />Just as an aside, my comment had nothing to do with using a para-foil, steerable parachutes or standard parachutes. It was a comment on the original designed, and operational Gemini landing system.<br />Gemini was not a base lander for two reasons, one of which was the carry-over from the idea of land based landings using something like the parafoil. The main reason was that the heatshield was so close to the doors of the capsule that had it been in the standard Mercury, (and later Apollo) 'nose-up' orientation it would have been VERY unstable in the water.<br />Also because it had an off-set CG to facilitate it's lifting entry profile, (CG was offset so that it 'flew' in a 'heads-down' attitude for the astronauts during reentry) it tended to rest with the hatches 'up' and above the waterline.<br /><br /> />However -- for G-X3, model 1, S/N 0000001, I see<br /> />Apollo-style 'two-drogue/three main' parachutes<br /> />and a bottom-first landing. <br /><br />All well and good, but if you'll look at your own illustrations, you'll note that by resting just on it's base the design is a bit unstable. Tipping over will be a real problem and NOT something passengers are going to look 'forward' to. If your going to change the design to be a bottom lander then your still going to have to incorperate some sort of 'stabilization' mechanism to keep it upright. This is going to be required to facilitate passenger unloading, and in case of emergency evac needs. (Mercury got away with base landing simply because it was expected that the pilot would remain in the craft until after pick-up. Gemini this was not a given and Apollo got around this by being so wide compared to it's height.)<br />Your also going to have to look at landing options where it does NOT come down where you wanted, such as a water landing.

 

[mrmorris]

<font color="yellow">"CG was offset so that it 'flew' in a 'heads-down' attitude for the astronauts during reentry"</font><br /><br />Just an addendum -- heads down was used for maximum lift. It did not maintain heads down throughout the entire flight. Likewise when they needed to steer right -- it was heads left, and vice versa to turn left. Once the flight profile was correct for a purely ballistic path, the capsule was put into a continuous spin to null out flight path changes due to the offset CG.<br /><br /><font color="yellow">"If your going to change the design to be a bottom lander then your still going to have to incorperate some sort of 'stabilization' mechanism to keep it upright. "</font><br /><br />It's possible. As I indicated when I posted the diagram -- it's both rough *and* primarily targeted towards determining if the volume existed to get five people into the same exterior dimensions as the original Gemini. I don't expect the G-X3 to have exactly the same dimensions as the diagram, and indeed mentioned in later posts that the diagram has since changed to accommodate five people in lieu of six, and to allow for the use of the APAS-89 docking mechanism at the nose. The APAS-89 alterations in particular have made G-X3 squatter. I haven't posted a changed diagram because every time I pull it up, <b>something</b> gets altered. I expect that to continue indefinitely. The final shape of the capsule might end up being closer to the Apollo capsule dimensions -- I have no problem with that. The Apollo RM actually had more lift than the Gemini, which gave it a greater cross-range. The downside would be that the Apollor RM was particular unsuited for a parafoil (if that turned out to be the direction to go for future versions for the spacecraft).<br /><br />Assuming a landing as accurate as is planned (i.e. within a mile or two of the target, and a helicopter pickup, I see no reason why the passengers and pilot can't stay in the craft

 

[mrmorris]

Just an FYI -- to everyone participating in the thread.<br /><br />Wanted to make sure everyone understands -- in case I'm coming across as too argumentative. I do appreciate all reasoned input into the thread -- whether or not I actually <b>agree</b> with the reasoning behind it. <img src="/images/icons/smile.gif" />

 

[rancamp]

mrmorris:<br /> />Just an addendum...<br /><br />Wanted to make sure we were all on the same page as it were <img src="/images/icons/blush.gif" />)<br /><br />As for assumed design, I was just going off the last picture I'd had. I'd thought that it would have gotten squatter after putting the adapter in the nose. But I wanted to put in my assesment of the vehicle <img src="/images/icons/blush.gif" />)<br /><br /> />The final shape of the capsule might end up being<br /> />closer to the Apollo capsule dimensions -- I have no<br /> />problem with that. The Apollo RM actually had more lift<br /> />than the Gemini, which gave it a greater cross-range.<br /> />The downside would be that the Apollor RM was<br /> />particular unsuited for a parafoil (if that turned out to<br /> />be the direction to go for future versions for the<br /> />spacecraft). <br /><br />A note here, why would the Apollo CM be 'unsuited' for a para-foil? It doesn't care particularlly how the spacecraft it's lowering is facing AND, with both the parafoil AND parawing chutes its possible to null out your approach rate to just about zero. Given a 'squater' design you don't even have to do that if your careful about the design. It won't tip. (Be a bit weird watching the landing from inside... but <img src="/images/icons/blush.gif" />)<br /><br /> />Assuming a landing as accurate as is planned (i.e.<br /> />within a mile or two of the target, and a helicopter<br /> />pickup, I see no reason why the passengers and pilot<br /> />can't stay in the craft until pickup.<br /><br />No reason at all. Though having the guy 'above' you in the rack retching his guts out from being sick might change ones mind. (Not to mention having to get that person OUT of the vehicle and in a positon NOT to choke on his own vomit would be a neccesity)<br />I've no problems with the helicopter pick up idea at all. Sounds in fact fine to me. But, again, what happens if you DON'T land on target? This is not something you can dismiss lightly. Accide

 

[rancamp]

>Wanted to make sure everyone understands -- in case<br /> />I'm coming across as too argumentative. I do<br /> />appreciate all reasoned input into the thread --<br /> />whether or not I actually agree with the reasoning<br /> />behind it.<br /><br />As long as the input is given a fair shake I'm good.<br /><br />Randy

 

[scottb50]

I haven't commented for a while, so here goes.<br /><br /> What I have seen is the design evolving (de-evolving?) into a specific craft that will win a prize, but is too compromised to consider for commercial use. Like SS-1 it has become a bare bones proof of concept, prototype.<br /><br /> As I see it SS-1 is a prototype for SS-2, which is planned for commercial service, and was needed to flight test the basic engineering. The X-Prize conveniently set the requirements, and paid back some of the costs of development. The problem being developing a commercial follow-up will still cost an awful lot and will still only get you sub-orbital.<br /><br />The difference between building a viable commercial design or a strictly experimental, goal determined, vehicle isn't that much. The cost of either is going to be high, having to duplicate the effort is self-defeating. Why not do it right from the start?<br /><br />Gemini, in the 1960's, already more than did the job SS-1 has done to prove the basic concept, and our tax dollars paid for it. A next generation Gemini doesn't have to re-prove the basic design it needs to be a production, commercial vehicle, just like SS-2, or whatever Branson is buying, is planned. <br /><br />Except who would want to go sub-orbital if you could get to orbit almost as easily? <div class="Discussion_UserSignature"> </div>

 

[mrmorris]

<br /><br /><font color="yellow">"A note here, why would the Apollo CM be 'unsuited' for a para-foil?</font><br /><br />Aerodynamics don't matter a great deal with a parachute, but they do indeed matter with a parafoil. The aerodynamic aspects of the Gemini are better for horizontal flight than that of the Apollo. <br /><br /><font color="yellow">"Though having the guy 'above' you in the rack retching his guts out from being sick might change ones mind. (Not to mention having to get that person OUT of the vehicle and in a positon NOT to choke on his own vomit would be a neccesity)"</font><br /><br />My understanding is that people tend to get sick from zero-G -- not from landing -- but to each his own, I suppose. As to your choking issue -- pretty please try to stay realistic. That happens to people who are unconscious to the extent they can't move themselves (i.e. they're drugged) and <b>alone</b>. If said sickie is conscious -- he/she can turn their head to the side and or use the barf bags. If unconscious -- there are four other people in the craft to assist. They're not superglued to their seats.<br /><br /><font color="yellow">"Accidents DO happen, navigation aids CAN fail, and they vehicle MIGHT put down in the middle of nowhere Sibera, or the Sahara. Assuming the passengers and pilot are going to stay in the vehicle till help arrives is a bit much when your cooped up inside."</font><br /><br />Off target -- certainly. OT to that degree? Again -- get real. There has <b>never</b> been a manned spacecraft that has landed that far off target in this history of the space programs of the world. Why don't you suggest engineering the craft to have a failsafe in the event it accidentally lands in the crater of an active volcano?<br /><br />The design I envision foe entry/exit from the craft is through the docking port at the top. I expect there to be either rungs along the 'floor' through the center aisle of the craft (and through the po

 

[mrmorris]

<font color="yellow">"The difference between building a viable commercial design or a strictly experimental, goal determined, vehicle isn't that much. The cost of either is going to be high, having to duplicate the effort is self-defeating. Why not do it right from the start?"</font><br /><br />My post immediately above this answers this at least in part, but I'll try a different tack.<br /><br />1. It'd be a crime if SpaceX were to try to develop a craft such as G-X3 -- with plenty of extra features that don't *have* to be included -- only to miss the January 2010 deadline by a few months because of it. The $50 million that they then forfeited would have gone a long way towards making substantial improvements in the craft.<br /><br />2. Your argument, and that of RanCamp seems to be that the first craft should be very close to the "production" version. Beyond violating the KISS principle, I have problems with that from a safety and performance standpoint. Throughout all of the design and calculations that I've been working with, I consistently try to be conservative -- always assuming larger masses, pessimistic power consumptions, and worst-case estimates on materials. Without flight data -- neglecting to do this is going to mean building a craft that might well fail spectacularly. I'm certain that computer modelling will allow the actual design team to reduce the safety buffers from the levels I'm using. However -- without actual flight data -- there's only so much of the safety factor that can be removed. What this means in terms of the spacecraft that's built is either it will have generous safety margins on all systems, or it there will be a significant potential that it will fail spectacularly. Once flight data from the craft is available -- some of the buffers will be reduced -- others left alone, still others might be increased. There's <b>no way of telling</b> ahead of time how this will affect the follow on design. It might end up being 5

 

[scottb50]

No matter how well you design 00001, 00002 is going to need a redesign. Given that -- why add things beyond the basic requirements to the design of 1 that increase the likelyhood that you'll fail to win a prize that will provide lots of *money* to assist in the redesign?<br /><br />Lot's of money? The X-Prize recouped less than 1/2 the acknowledged development costs and I bet a true production version will cost a great deal more.<br /><br />2010 is a long way away, relatively, and there are other existing launchers that could put a Gemini 3 in orbit, more expensively than the Falcon V, presumably, but Sea Launch and a number of other boosters could easily do the job. I just don't see it taking five years in development. More like three, considering reasonable backing.<br /><br />Maybe Bush is right the Moon by 2020 and maybe Mars by 2040 with no commercial use of Space being developed. I would like to see a return to the Moon by 2010, if everybody insists we have to do that and Mars within five years of that. Government can't do it, but private industry can. <div class="Discussion_UserSignature"> </div>

 

[rancamp]

Me:<br /> />A note here, why would the Apollo CM be 'unsuited' for a para-foil?<br /><br />mrmorris:<br /> />Aerodynamics don't matter a great deal with a parachute, but they do indeed matter with a parafoil.<br /> />The aerodynamic aspects of the Gemini are better for horizontal flight than that of the Apollo.<br /><br />Actually the aerodynamics of either won't matter much at subsonic speeds. Either would have about the 'same' characteristics under a para-foil or ram-air chute.<br /><br />As for the "in-and-out" portion of the message. I'm sorry but I needed to get clarification on HOW it was being done. I'd looked over the entire thread and it wasn't clear. So I 'over-did' it in my comments to get you to post a more specific plan. Sorry but I couldn't think of a shorter way to get the picture.<br /><br />Specifically though:<br /> />They're not superglued to their seats.<br /><br />No but there is little room to move in the desing AND the vehicle is going to be 'off-balance' sitting on it's base as proposed. I thought I might illustrate this with the comments.<br /><br /> />Off target -- certainly. OT to that degree? Again -- get real. There has never been a manned spacecraft that has landed that far off target in<br /> />this history of the space programs of the world.<br /><br />Soyuz. One crew had to wait over 24 hours before recovery crews arrived. There are light aircraft that go down on occasion that take days to find with a concentrated search. Crash beacons help, but even still it can take a long time to find them.<br />Barring that, 9/10ths of the Earths surface is covered by water. Take your 'optimum' landing site of Edwards. Land short by a little over 100 miles and your in the Pacific, long and north and your in the Great Salt Lake. This HAS to be taken into consideration. We're building a passenger craft.<br /><br /> />Why don't you suggest engineering the craft to have a failsafe in the event it accidentally lands in the crater of<br /> />an active volcano?<br /><</safety_wrapper>

 

[rancamp]

>1. It'd be a crime if SpaceX were to try to develop a craft such as G-X3 -- with plenty of extra features that don't *have* to be included --<br /> />only to miss the January 2010 deadline by a few months because of it. The $50 million that they then forfeited would have gone a long way<br /> />towards making substantial improvements in the craft. <br /><br />It would be even worse to NOT include items that ARE needed, and have the craft win the prize but NOT be brought on as a commercial craft because it wasn't 'finished' enough. Or worse yet not complete the prize requirements on time because we forgot something.<br /><br />2. Your argument, and that of RanCamp seems to be that the first craft should be very close to the "production" version.<br /><br />Like any other 'prototype' production craft. Unless your building a SS-1 win-the-prize-and-worry-about-a-commercial-version-later type craft, that is what we're talking about.<br /><br />You've a good point that your being 'conservative' with your calculations and I appreciate that. But give me some credit for asking the questions I feel you've overlooked.<br /><br />You CHANGED some fundemental parts of the old design and have not taken into account what those changes mean to the OVERALL design. Your also making some assumptions that I don't feel right about letting go by without question. THAT'S what I'm doing.<br /><br />A 'real' design team might find hundreds of pounds cut from the design that we missed. On the converse side it's always easier to DROP items from a design than to add them. We might want to actually run a little closer to the margin AND make sure the craft has everything it needs to do it's basic job. I'm not suggesting overcomplexity OR avoiding the KISS principle, but I AM asking that you examine some of your assumptions on the design.<br /><br />IF all we're doing is going for a win of the prize and redesign the vehicle after we've won, lets just take the dimensions of the Falcon-V payload shroud and w

 

[rancamp]

mrmorris:<br /> />planned to launch Falcon-I about this time last year. It's now been pushed back how many times?<br /> />It keeps getting pushed because everything is more complex than you expect when you start out.<br /><br />In actuality it's less a complexity issue or engineering issue as legal issues. See:<br /> />http://www.hobbyspace.com/Links/RLVNews.html&lt;<br /><br />(See under 22 January entry)<br /><br />It's actually Northrop Grumman and Boeing issues.<br /><br />Randy

 

[mrmorris]

<font color="yellow">"Lot's of money? The X-Prize recouped less than 1/2 the acknowledged development costs and I bet a true production version will cost a great deal more. "</font><br /><br />$50 million is very probably not enough to develop the capsule, I agree. So you're saying that means it's not wrth having the 50ml after spending (WAG) 75m to develop it?<br /><br /><font color="yellow">"...there are other existing launchers that could put a Gemini 3 in orbit..."</font><br /><br />G-X3 is light enough that just about any launcher in use today (excepting micro launchers like Pegasus) can put it into orbit. However -- only the F-V can do do for a price that is low enough to have any possibility of being profitable under the contract offered by Bigelow. He's offering 33million per launch. Find me a launcher other than the F-V that allows a profit given this figure. Recall that it must be based in the US, as that's another requirement.<br /><br /><font color="yellow">"I just don't see it taking five years in development. More like three, considering reasonable backing. "</font><br /><br />If Paul Allen were to throw in and offer a hundred million or three of capital -- I fully agree. Absent that -- and assuming a small firm developing it -- five is tight.

 

[mikejz]

At $33 Million per flight I am not so sure about the profitablity of such a program. After all I have a strong feeling that the Falcon V's price will be rising to around $20 Mil per flight with the upgraded capacity. <br /><br />That does not leave room for a lot of profit. <br /><br />Unless he is talking about a volume of 15-20 launchers per year I'm not sure it would be a profitable venture.

 

[mrmorris]

<font color="yellow">"There are light aircraft that go down on occasion that take days to find with a concentrated search.</font><br /><br />Light aircraft don't generally have a dedicated team using radar, telemetry, etc. watching their flight path like a hawk. <br /><br /><font color="yellow">"Barring that, 9/10ths of the Earths surface is covered by water."</font><br /><br />Apparently we live on different planets. The one I live on is 70% covered by water.<br /><br /><font color="yellow">"Gemini orginally landed horizontally, changing it to a base landing design IS a large change. What is it going to effect and how will it have to be modified to encompass this change?"</font><br /><br />Actually the fact that I plan a ground landing is a <b>much</b> larger change than the mostly-horizontal to vertical landing. The water landing provided for considerable G-force impact attenuation. In that -- I've made several engineering attempts to ensure this is feasible (Apollo 3-parachute system in lieu of single Gemini chute, crumple zone at the base, shock-absorbers in the crew seats).<br /><br />By contrast -- the vertical landing of the Gemini is a fairly small change. You keep saying that this will be unstable. However -- we're talking about a cone -- about ten feet wide and fifteen feet tall. In general, a cone is a pretty stable geometric shape. Arguably it'd be *more* stable if it were fifteen wide and ten tall, but even given these dimensions -- it's not going to prove nearly the problem you suggest.<br /><br />There are a couple of things that would improve the situation. I have mentioned earlier in the thread that I plan to use the full eleven-foot diameter of the F-V rather than the ten feet of the original Gemini Capsule. It also possible to design the crumple-zone at the base of the G-X3 such that it spreads radially outward as it collapses (widening the base still further).<br /><br /><br /><font color="orange">"Where exactly would you</font>

 

[mrmorris]

<font color="orange">"It keeps getting pushed because everything is more complex than you expect when you start out. "</font><br /><br /><font color="yellow">"In actuality it's less a complexity issue or engineering issue as legal issues."</font><br /><br />Yes -- that's been posted and discussed on this board as well -- weeks ago. See the 'SpaceX and Northrup' thread in 'Business and Tech'. That disupte hasn't set them back a year -- it's set them back about three months. The Falcon I was initially supposed to launch in late 2003, then early 2004, then mid-2004, then late-2004, then first thing 2005, now March 2005. If you read through their update archives -- the reasons for all but the last two postponements are technical, not legal.

 

[mrmorris]

<font color="yellow">"At $33 Million per flight I am not so sure about the profitablity of such a program. After all I have a strong feeling that the Falcon V's price will be rising to around $20 Mil per flight with the upgraded capacity. "</font><br /><br />At either price, the Falcon V is as cheap as it gets. If it isn't profitable, then nothing will be until something trumps the V. I don't have any way of getting hard numbers on what the expenses outside the launcher would be, so I can't speculate where the cutoff is for profitability.

 

[mrmorris]

Cool -- SpaceX is in the process of aqcuiring a Canaveral launch site! One more step towards being able to launch a manned flight.

 

[neuronexmachina]

I'm not sure if you've seen this already, but RLV News (a prominent space news site) mentioned this thread on their site:<br /><br />http://www.hobbyspace.com/AAdmin/archive/RLV/2005/RLVNews2005-01.html#Jan.18.05<br /><br />A visitor to RLV News who happens to be an engineer posted some potentially helpful info. Basically, he favors a lifting body approach:<br /><br />http://www.hobbyspace.com/AAdmin/archive/RLV/2005/RLVNews-Feedback.html#Jan.24.05

 

[mrmorris]

Cool -- I R famous.<br /><br /><font color="yellow">"A visitor to RLV News who happens to be an engineer posted some potentially helpful info. "</font><br /><br />Engineer or not, his figures are off. Gemini re-entries max loads averaged around 4 G's. The <b>Liberty Bell 7 flight</b> approached 12 G's, but the average for Mercury was supposed to be a bit under 8. Soyuz flights average 4 G's. <br /><br />---------------------------------------------------------<br /><br />Liberty Bell 7<br /><i>During reentry, Gus experienced 11.2 G’s, or 11 times his body weight. </i><br /><br />Gemini IV<br /><i>The reentry gauge con indicated that they were high; there might be an overshoot the landing point. Cooper, responding to the instrument, slewed to 90 degrees left instead of 53 to create more drag and reduce the landing error. The g-loads quickly shot from 2 1/2 to 7 1/2.</i><br /><br />(The high G-loads were responding to a major failure in the initial burn caused by bad tracking data being sent to the capsule to start the DO burn. Note it's still nowhere near 12-15 G). <br /><br />Gemini V<br /><i>During the long glide, which did not have a sharp angle of descent, g forces never rose higher than 3.9 (contrasted with an average of 7.7 for the Mercury-Atlas orbital flights). </i><br /><br />Gemini VII <br /><i>The pilots, accustomed to Zero-G for two weeks, felt as if they weighed much more than they really did. Even so, during reentry in the Gemini capsule, the G-Forces never went up to more than four G's.</i><br /><br />Soyuz<</safety_wrapper>

 

[tap_sa]

<font color="yellow">"The Falcon-V does not have the capacity to handle anything like the X-38. It's a capsule or nothing."</font><br /><br />The engineer was re-engineering Falcon V:<br /><br /><i>So my vote goes to a 4-5 man lifting body close to the X-24 / 38 shape in top of a Falcon V <b>with a high energy second stage ( Centaur ).</b></i> <br /><br />Even if that was doable it would ruin Falcon's main strength, price. And first stage would need re-design to support the additional weight.<br /><br />BTW why all those US lifting body designs (X-24/X-33/X-38) all still have huge fins/stabilizers, don't they know how to make lifting <i>and steering</i> body? Kliper appears to do fine without any protruding vanes.

 

[mrmorris]

<font color="yellow">"The engineer was re-engineering Falcon V: "</font><br /><br />I know -- but that still wouldn't do it. I sent a more detailed version of my last post to the editor of RLV News. Hopefully they'll post it. In addition to the mass issues -- the size is also a problem. The 1/6th scale X-38 was 14.5 feet wide and <b>way</b> too small to fit four passengers. Even if doubling the size would allow 4 people (doubtful -- it'd still be 1/3 the size of the planned craft and it was expected to hold eight people), that would make it 29 feet wide. The Falcon V is only 12 feet wide. Even if you completely disregard the fact that the launch mass is *way* outside F-V's range, it's dimensions simply too small for such a craft.

 

[rancamp]

To ge to the point of the conversation:<br />Me:<br /> />So far what 'unneccesary' features have I suggested? None really.<br /><br />mrmorris:<br /> />Based on your original link and concerns about the vertical landing, you're looking for landing struts,<br /><br />Braces of some type actually. They could be as simple as sping loaded bars that 'pop' out. Nothing major and since your going to be nose heavy the 'cone' shape is going to be less stable on the ground. That's all I was suggesting. You've rejected it so we can move on.<br /><br /> />..a door at the base, and a ladder.<br /><br />Not really, I simply showed a pic for a similar landing vehicle. (Much higher mass though) as an example of my idea. YOU then asked what was MY personal idea. I gave it. No sweat off my brow that it's not possible. YOU asked I answered.<br />End of Story.<br /><br /> />From your posts to that point, you spent many words discussing just how critical it was that there be some<br /> />other means of leaving the craft that didn't subject the crew to having to climb to the top.<br /><br />Which was in search of a more definate 'word' picture of how things were going to go together. As you'll note I already said I have no problem with the nose adapter NOW that you've fully explained it.<br />Again, end of story.<br /><br /> />I do disagree that the craft is unstable in a bottom-first landing. <br /><br />Disagree all you want. Given it's nose heavy mass it's still a good possibility that it will tip on landing. I mearly point this out as info. Take if for what it is and don't read too much into it.<br /><br /> />I don't disagree that a second door to the craft would be nice, but it is not necessary by any means. <br /><br />I never actually said it was. Again it would be nice, (we agree) but not needed in this design. Your harping on a point I already agreed to let drop.<br /><br />Me:<br /> />There are light aircraft that go down on occasion that take days to find with a concentrated search. <br /><br />mrmo

 

[rancamp]

mrmorris:<br /> />Yes -- that's been posted and discussed on this board as well -- weeks ago.<br /><br />Forgive me but I've only been following THIS thread ;o)<br /><br />Randy

 

[rancamp]

Tap_Sa wrote:<br /> />BTW why all those US lifting body designs (X-24/X-33/X-38) all still have huge fins/stabilizers, don't they know how to make lifting and<br /> />steering body? Kliper appears to do fine without any protruding vanes.<br /><br />NASA did studies on Lifting bodies without any external vanes. They found that shifting CG, (as Gemini and Apollo did) worked fine. The problem is there was a percived need for 'wings' of some type in most designs. The NASA lifting bodies all, (pretty much anyway) flew in the early 60s. We know better now ;o)<br /><br />There was a technical report that Centuri rockets, (a model rocket company) had published that went with this rocket:<br />http://www.dars.org/jimz/ka-12.htm<br /><br />which showed a 'no-fin' Shuttle vehicle idea using shifting CG control.<br /><br />It's doable. How well it would, or would not compare would take some number crunching.<br /><br />Randy