Pros and cons with DC-X and other LVs.

qso1 · Apr 10, 2008

I changed the title a tad so that discussion of other LVs can continue under this thread. We had gotten away from the DC-X discussion but by all means, the DC-X can still be discussed here. <div class="Discussion_UserSignature"> My borrowed quote for the time being:There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened. </div>

scottb50 · Apr 11, 2008

The problem I see with this one is not so much weight as it is aerodynamics and structural loading...If you look at the latest business jets the idea is a wing that carries the majority of the structural loads with the fuselage attacked to it. Most commercial airlines go one better by putting all of the high stress loads on a single section of the aircraft, engines and landing gear both mounted to the main structure of the aircraft. What I am talking about is the same thing, the propellant tanks and SRB housings attach to the wing structure rather then carrying flight or landing loads. I also think it could be lighter to mount the main liquid engines to their own dedicated tanks rather then adding structure to the wing itself, this would allow the whole assembly, tank and engine to be replaced quickly or just the engine changed if a problem occurs.My other idea is to make the SRB a similar part of the airframe, the difference from the Shuttle would be replacing the current Segment design to a single piece composite tube and multiple segments loaded with propellant in to it. When it returns you unbolt the nozzle, remove the spent segment outer casings, insert new ones and bolt the nozzle back on.In your original post, you mentioned 80 miles which lead me to think you were separating and turning around at that altitude. 20 or 30 miles would be sufficient because a powerful enough upper stage will get the rest of the job done. But rather than try to make an ET/SRB combo of any kind for this task....I did mention that, but more as a reference to the Shuttle system. I agree a lower altitude would be better, but the size of the Upper Stage then comes into play. What I intend is the tanks of the Upper Stage would be reused in LEO as components of Stations and Vehicles. Engines would be used for Tugs and lunar, Martian or asteroid and comet missions, sent back for overhaul as needed.  I'd say start fresh, the ET/SRB combo is simply not designed to be a Fly Back Booster (FBB)...That is the intent, but I also want to be able to use existing Shuttle infrastructure as much as possible. I think the air launched idea is the way to go, but I don't see something like the Spaceship one or two type vehicle being capable of delivering a commercially viable payload. Pegasaus uses an L-1011 to orbit less then 2,000 pounds of payload. All liquid has the same limitations, solids provide the most thrust initially, when it is needed, with a flyback booster like this the housings are light enough they would reduce the acceleration from when they burn out to when the Upper Stage is released, but that would again become a factor of the scale of the Upper Stage.One idea would be a pitch over at SRB burnout to a shallower ascent from say 20 to 40 miles before Upper Stage release, further downrange, but if you use the jet engines for launch and they basically carry their own weight it doesn't really matter. Where did you hear or see they are not suitable for reuse? My understanding is that the SRBs have been reused but its usually that sometimes the segments that fly together on one booster may fly as parts of other boosters, but they are reused....Most of the references I have found is it is probably cheaper to just build new segments, after recovery, shipping, refurbishment and reshipping not a lot is saved. I would also expect a lot of testing needs to be done and maintaining exact mating dimension would be a problem with different flexing across joints.My idea is a solid Carbon/Carbon shell with propellant cast inside it that is inserted into a single piece tube. Re-usability, other then recycling to build new Segements would not be an issue for the shell, it would degrade to protect the outer housing.The ET could however, be placed in orbit for other uses but there again, it would depend on making the idea economically attractive....To take the ET to other then a short term parking orbit would severly limit any Shuttle mission. I doubt they could put an ET into a recoverable orit and then reach the ISS as an example. The other problem is the insulation needed on the ET, it would present a lot of problems as it degrades, leaving a fast moving cloud of debris expanding around a specific orbit. I also doubt the structural capabilities of the ET would be up to prolonged use, the H2 tank would be pretty vulneral to and too big to provide escape in an emergency.  <div class="Discussion_UserSignature"> </div>

qso1 · Apr 16, 2008

The problem I see with this one is not so much weight as it is aerodynamics and structural loading...If you look at the latest business jets the idea is a wing that carries the majority of the structural loads with the fuselage attacked to it. Most commercial airlines go one better by putting all of the high stress loads on a single section of the aircraft, engines and landing gear both mounted to the main structure of the aircraft. What I am talking about is the same thing, the propellant tanks and SRB housings attach to the wing structure rather then carrying flight or landing loads. I also think it could be lighter to mount the main liquid engines to their own dedicated tanks rather then adding structure to the wing itself, this would allow the whole assembly, tank and engine to be replaced quickly or just the engine changed if a problem occurs.It would probably help me understand this idea better if you could work up a sketch of the configuration in a paint program. Just judging by what your posting, it still seems to me that just starting fresh would be the better approach, especially from a cost perspective. My other idea is to make the SRB a similar part of the airframe, the difference from the Shuttle would be replacing the current Segment design to a single piece composite tube and multiple segments loaded with propellant in to it.This idea alone requires addition of much more powerful cranes to the VAB for stacking ops. One of the reasons the SRBs are segmented is that they weigh over 500 tons stacked and the VAB cranes max capacity is 250 tons IIRC.I imagine bigger cranes can be installed but this would require structural strenthening to the VAB, especially the roof. Some of the other mods you have mentioned sound like they would require extensive mods to the VAB. I did mention that, but more as a reference to the Shuttle system. I agree a lower altitude would be better, but the size of the Upper Stage then comes into play. What I intend is the tanks of the Upper Stage would be reused in LEO as components of Stations and Vehicles.This is not a bad idea. Reuse of upper stage tanks as components of stations etc. That is the intent, but I also want to be able to use existing Shuttle infrastructure as much as possible. I think the air launched idea is the way to go, but I don't see something like the Spaceship one or two type vehicle being capable of delivering a commercially viable payload.I agree that a Spaceship 1 or 2 would not be viable for delivering construction type payloads. They would do the job of delivering personnell while utilizing SSTOs, 2STOs or off the shelf but more economical LVs for delivering large and heavy payloads. Pegasaus uses an L-1011 to orbit less then 2,000 pounds of payload. All liquid has the same limitations, solids provide the most thrust initially, when it is needed, with a flyback booster like this the housings are light enough they would reduce the acceleration from when they burn out to when the Upper Stage is released, but that would again become a factor of the scale of the Upper Stage.One idea would be a pitch over at SRB burnout to a shallower ascent from say 20 to 40 miles before Upper Stage release, further downrange, but if you use the jet engines for launch and they basically carry their own weight it doesn't really matter.Most of the references I have found is it is probably cheaper to just build new segments, after recovery, shipping, refurbishment and reshipping not a lot is saved.That makes more sense and is probably one of the contributing factors to the overall high cost of shuttle missions. I would also expect a lot of testing needs to be done and maintaining exact mating dimension would be a problem with different flexing across joints.My idea is a solid Carbon/Carbon shell with propellant cast inside it that is inserted into a single piece tube.There have been proposals in the past to do this. Cast a one piece solid rocket booster. It was apparently less expensive and technically challenging to develop segmented boosters considering the shuttle SRB was, and still is the largest solid rocket booster design ever constructed and operated.The ET could however, be placed in orbit for other uses but there again, it would depend on making the idea economically attractive....To take the ET to other then a short term parking orbit would severly limit any Shuttle mission.I agree with placing the ET into orbit for other use is certainly a good idea. Unfortunetly, there is currently no demand for payloads of the size that could be fit into an ET. I doubt they could put an ET into a recoverable orit and then reach the ISS as an example. The other problem is the insulation needed on the ET, it would present a lot of problems as it degrades, leaving a fast moving cloud of debris expanding around a specific orbit. I also doubt the structural capabilities of the ET would be up to prolonged use, the H2 tank would be pretty vulneral to and too big to provide escape in an emergency. Posted by scottb50To get ET to an ISS orbit will require a booster for the ET that can reach ISS orbit. Your right, ET insulation might be a problem as it peels or flakes off over time. Good point as well on escaping from the LH2 tank portion of the ET. A lot of attention would have to be paid to this area to make a habitable on orbit ET.I have illustrated concepts of putting ETs into orbit and didn't put much thought into the foam shedding that might occur over time. But then, I did mine for graphic novels.  <div class="Discussion_UserSignature"> My borrowed quote for the time being:There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened. </div>

scottb50 · Apr 16, 2008

This is the basic idea.http://www.photodump.com/Scottb50/Copy%20of%20Configurations.htmlThere are two components; the Segment and a Tube. The simplest Module is two Segments and a single Tube. By configuring the inner surface of the Segment end it can be either open or closed. Closed it passes over the Tube at one end and contains the ened of the Tube at the other. With both ends open muliple Segments can be used over different length Tubes.The simplisity is it can be made in any scale. If we are talking about the vehicle we are discussing Tubes would be 15 feet in diameter and 30 feet in length. A Module to power a Hydrogen/air fuel cell could use a 1/2"x8" Tube. With the same basic design pretty much any container could be made by simply varying the dimensions of the common design.Since each Segment consists of an identical end, that can attach to any other identical Segment end various length Modules can be connected together as needed. The central band of the Segment also has four smaller versions of the Segment ends that can attach to other identical size Segment. This can be used as a simple adapter or configured with a hatch for transfer or other various specialized ports as needed.  <div class="Discussion_UserSignature"> </div>

qso1 · Apr 16, 2008

I looked at your graphics and indeed, very interesting. Since they bear little resemblance to any of the shuttle components other than maybe scale. It seems this would be that "Start fresh" idea I mentioned in earlier posts. And an excellent one at that. The use of modularity being its most attractive and potentially economical feature.What graphics program did you use, me being a graphics dude myself, I'm always curious about the programs used for various tasks. Or did you do them by hand and scan them. <div class="Discussion_UserSignature"> My borrowed quote for the time being:There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened. </div>

scottb50 · Apr 17, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>I looked at your graphics and indeed, very interesting. Since they bear little resemblance to any of the shuttle components other than maybe scale. It seems this would be that "Start fresh" idea I mentioned in earlier posts. And an excellent one at that. The use of modularity being its most attractive and potentially economical feature.What graphics program did you use, me being a graphics dude myself, I'm always curious about the programs used for various tasks. Or did you do them by hand and scan them. Posted by qso1</DIV>I bought a few programs but, I hate to say it, Paint jusy works easier for me. If it was to design to deveolpoment obviously it wouldn't, but to sketch out an idea it seems to e the easiest I have been able to find. Sometimes things don't look perfect, but at this point it is more important to express the idea then define the design.The scale to Shuttle is because it is based on the SSME, specifically and a version of the SRB that basically uses the existing nozzle, bolted to a completely different propellant housing. The basic idea is instead of segmented SRB's we use segmented propellant Modules. They are stacked on the nozzle and the vehicle is lowered over them, the nozzel sections are then bolted into place. This would fit with the existing Shuttle cranes.   <div class="Discussion_UserSignature"> </div>

qso1 · Apr 17, 2008

Paint works quite well for a lot of applications. I use i myself for sketching out ideas on the fly. I had no idea it was paint when I looked at your graphics. As for stacking the propellant modules on the nozzle. As long as they are below that 250 ton crane limit, they're fine.As I'm sure your well aware, the problem with SRBs is that they are already loaded when arriving at KSC whereas, liquid propelled vehicles such as the winged vehicle you conceptualized, or liquid rockets would be empty during VAB processing.I like the modularity of your idea. I think thats something NASA has somewhat gotten away from.  <div class="Discussion_UserSignature"> My borrowed quote for the time being:There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened. </div>

scottb50 · Apr 17, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>As I'm sure your well aware, the problem with SRBs is that they are already loaded when arriving at KSC whereas,  Posted by qso1</DIV>Here the idea is the Modules would house pre-packaged inserts. Basically a thin wall composite with a Carbon/Carbon inner surface. The inserts would be stacked on the nozzle Segment and the Launcher would be lowered over them. The Tube the inserts go into would be single piece composite encased in the outer Segments. This would remove the chance of a Challenger type failure as well as greatly reduce the weight of the SRB.Once back on the ground the aft Segment of the SRB would be removed, the insert casings would be removed and the vehcle is ready for restacking with fresh inserts. Spent inserts could be returned to the loading facility and refilled for later use.      <div class="Discussion_UserSignature"> </div>

qso1 · Apr 18, 2008

That would get around the VAB crane capacity. I just wonder why this type of design hadn't been thought of before, or if it had been thought of but considered maybe too expensive. The industrial design process usually starts with proposed Cadillacs and ends with operational VWs.  <div class="Discussion_UserSignature"> My borrowed quote for the time being:There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened. </div>

scottb50 · Apr 18, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>That would get around the VAB crane capacity. I just wonder why this type of design hadn't been thought of before, or if it had been thought of but considered maybe too expensive. The industrial design process usually starts with proposed Cadillacs and ends with operational VWs.  Posted by qso1</DIV>Propably because the customer for hardware has been the government, just like the aircraft industry. There would have been no 707 without the KC135 and the fundemental design is still being built today, the 737. The Delta started out as military hardware and was marketed the same way, except it was not as much of a redesign as the 707 was.The Shuttle ended up the same way, money was the least important issue, they had to add all the options to pull the military in and that made it over capable, and too expensive, for commercial payloads. The simpler it can be done the better, but you also run into the scale of simply getting something into Space period.To become economical enough for routine use it has to be as simple as possible. Starting with existing infrastructure and proven engines and SRB nozzles and simplifying the primary structure by using just two pieces of hardware makes it about as simple as it gets. <div class="Discussion_UserSignature"> </div>

qso1 · Apr 21, 2008

Propably because the customer for hardware has been the government,I think your right about the government as customer.  just like the aircraft industry. There would have been no 707 without the KC135 and the fundemental design is still being built today, the 737.The 707 I'm not so sure. The way commercial aircraft industry works is the aircraft won't be developed until a certain number of orders are put in. These orders are from airlines and the military. When the military orders, they pay the airline and get their aircraft to do with as they see fit and as the design allows. The 707 was relatively easy to convert to KC-135 spec.Whereas the DOD was involved in the shuttles development from the getgo. Defining the payload and cross range maneuverability requirement to fit their needs. NASA had to develop the shuttle to fulfill DOD requirement which involved considerable money and effort, mostly at NASAs expense. The Delta started out as military hardware and was marketed the same way, except it was not as much of a redesign as the 707 was.Do you mean the Delta rocket? If so, that started as the Thor Delta around 1960 and it was pretty much derived from the Thor, a mostly military rocket which came in several derivitives including the Thor Delta.The modern Delta-IV rockets were also designed as you mentioned...for the DOD as part of the EELV program. The Shuttle ended up the same way, money was the least important issue, they had to add all the options to pull the military in and that made it over capable, and too expensive, for commercial payloads.The main options being 1,200 mile re-entry cross range, a 65,000 pound payload capacity and ability to launch from Vandenberg AFB. Money was an important consideration to NASA. The Nixon Admin gutted NASAs ambitious post Apollo plan which left only the shuttle. And then, only if it could be developed for no more than $5.5B (1971) dollars. The DOD didn't have to foot the bill for shuttle development. The simpler it can be done the better, but you also run into the scale of simply getting something into Space period.To become economical enough for routine use it has to be as simple as possible. Starting with existing infrastructure and proven engines and SRB nozzles and simplifying the primary structure by using just two pieces of hardware makes it about as simple as it gets. Posted by scottb50[/QUOTE]Couldn't agree more. Especially in the realm of human spaceflight.  <div class="Discussion_UserSignature"> My borrowed quote for the time being:There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened. </div>

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