Pros and cons with DC-X and other LVs.

spacelifejunkie · Apr 2, 2008

"They are giving that money to China ? or those countries giving them money?Why work on solar power?" Gene Myers claimed that those countries were going to give SIG $10 Billion to develop the launchers and do some demonstrations of SSP.  SIG wants to lease their stations to different countries/utilities to construct and maintain the very large satellites.  Very ambitious and IMHO, not doable.  A great vision but I'm not sure it's possible.   SLJ

scottb50 · Apr 2, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>To me it would. For one thing, you would be able to use the DC-X in the size it originally was flown rather than the much larger planned DC-X follow on, the DC-Y. It might be more cost effective to develop a new launch system for the DC-X type vehicle and station type payload. In the MOL program, a Gemini capsule sat atop the MOL station which in turn sat atop a Titan IIIM rocket. Although the Gemini wasn't a DC-X, the idea is not so far off from the SIG idea. As for SIG, my only problem with em is not their concepts, its that they so far, have only made nice websites and concept CGI. I'd like to see them go much further but apparently, they have not been able to get the capital needed or they went deep black as in, top secret.  Posted by qso1</DIV> The biggest problem I have with the concept is the amount of propellant needed for a vetical landing. With a winged vehicle you can reduce the need enough to allow at least a go-around and second attempt or some cross range manuevering. The added propellant from eliminating the wing structure would gain you a minimal hover time at the very least.Either way you have to look at the mass fraction equations, a capsule would be cheaper, followed by a glider, Shuttle, a powered lander and finaly  by  vertical lander.  <div class="Discussion_UserSignature"> </div>

qso1 · Apr 2, 2008

True, there would have to be enough propellant to gently land an SSTO/2STO vertically what with the hovering that may be required. Autoland type systems should be able to keep that phase of flight at an optimal level but without actual tests, we can't be sure.I don't see how a vertical lander would be more expensive than a shuttle...or at least the shuttle we developed. Unless you mean expense as in aerodynamics rather than monetary. Of all the concepts you mentioned, as I see it all would work.We know capsules, gliders which covers shuttle when it lands in addition to lifting bodies tested over the years, work. Jury is still out on powered and vertical landers. Its just a matter of determining which would be the most cost effective.I've seen on this board, people who favored capsule designs over winged in the small spaceplane world because they always say bringing wings along is a waste. I don't agree with that view totally because if a winged vehicle can offer robust, economical operation. Seems to me it would be more advantageous than a capsule, especially where cross range maneuvering is a concern.  <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 3, 2008

I can't see anway a vertical landing vehicle could take less propellant then a horizontal powered design.  I mean it looks good in the movies but in reality you have to support the entire weight of the vehicle with propellant from the point you transition from glide to landing. Without vestiagle wings your glide is going to resemble a brick. That intails slowing to zeo forward velocity an descending from there to the surface.  It might look good in the movies but in reality i won't work. Then factor in lifting off and reaching an orbit, after having landing, with the propellany you brought with you, and it exceeds credibility.   <div class="Discussion_UserSignature"> </div>

qso1 · Apr 3, 2008

I would say at the very least, a DC-X type vehicle would need so much propellant for doing what you said, that there would be little left in the way of useful payload.But apparently the aerospace industry thought it could be done judging by the programs proposed in the 1960s and the revival of the concept in the 1990s thru the DC-X. But at the same time, it has yet to actually be done, at least with an SSTO. So the aerospace industry has probably had to give up on the idea.Even they acknowledged the 1960s design would have been impossible had a vehicle actually been built then because the lighter materials required to make it light enough didn't even exist then and apparently barely exist now.On a 2STO, one of the advantages would be more ascent propellant capability could be freed up to become descent propellant since the booster stage of a 2STO would provide much of the ascent propellant initially.  I guess nows the time to see if private industry, currently in the form of Blue Origins with their DC-X derived SSTO design, is up to the task.  <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 4, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>I would say at the very least, a DC-X type vehicle would need so much propellant for doing what you said, that there would be little left in the way of useful payload.But apparently the aerospace industry thought it could be done judging by the programs proposed in the 1960s and the revival of the concept in the 1990s thru the DC-X. But at the same time, it has yet to actually be done, at least with an SSTO. So the aerospace industry has probably had to give up on the idea.Even they acknowledged the 1960s design would have been impossible had a vehicle actually been built then because the lighter materials required to make it light enough didn't even exist then and apparently barely exist now.On a 2STO, one of the advantages would be more ascent propellant capability could be freed up to become descent propellant since the booster stage of a 2STO would provide much of the ascent propellant initially.  I guess nows the time to see if private industry, currently in the form of Blue Origins with their DC-X derived SSTO design, is up to the task.  Posted by qso1</DIV> I would think a vertical landing would be comparable to a conventional landing if we are dealing with turbojet engines. The problem changes when you look at rocket engines and expect those same engines to reach orbital velocity as well as transition to a landing attitude. The other side of the situation is you can't expect to drop straight down to a point you ignite the engines for  landing, even the DCX proposal was an aerodynamic descent with a translation to veticle for landing.Ideally what is needed is a vehicle that re-enters like the Shuttle and has low altitude cross-range capability as well as a powered approach for a conventional landing and go-around and diversion capability. This could easily be done with the Shuttle design if you limit the vehicle to a launch to an orbital facility and a return. Get rid of the mid-deck facilities and make it a bus instead of an RV.The ISS has a manipulator arm system, so that could be eliminated unless something like the Hubble mission is needed.What I would like to see is the remaining Shuttle fleet privatized and kept in operation. Not NASA, but they could contract launches. The vehicles have barely touched their lifespans, they could fly for another 20 years easily. <div class="Discussion_UserSignature"> </div>

qso1 · Apr 4, 2008

The DC-X demonstrated landing pretty well I thought. But it was only a subscale demonstrator. A parachute system could be used to set it vertical prior to landing, and even cut down on propellant use. It might be a little expensive to recycle chutes tho.Costwise, the shuttle itself has proven too expensive to operate on a commercial basis. Half a bill per flight is too much money and 4 to 6 flights per year way to few for commercially viable operation. I agree the shuttles could fly a lot longer but only the govenment can afford it and barely so, and only because they spend tax dollars to keep it flying.If you were to take it and make it a passenger vehicle. You could get more people per flight by converting an old Spacelab or hab module to a passenger carrier.Private interests are working on various solutions such as Scaled Composites Spaceship 2 which itself is suborbital but may lead to an orbital version, and its a winged vehicle. Blue Origins, an SSTO based on the clipper design but a squatter design that has what appears to be better stability. Space "X" favors the rocket capsule approach which might be economically doable in their hands.NASA tried to develop an economical shuttle replacement but NASA budgets are just not high enough to allow successful development as evidenced by the failure to bring about the DC-Y or Venture Star. NASA is back to capsules after nearly two decades pursuing a shuttle replacement.  <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 4, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>The DC-X demonstrated landing pretty well I thought. But it was only a subscale demonstrator. A parachute system could be used to set it vertical prior to landing, and even cut down on propellant use. It might be a little expensive to recycle chutes tho.Costwise, the shuttle itself has proven too expensive to operate on a commercial basis. Half a bill per flight is too much money and 4 to 6 flights per year way to few for commercially viable operation. I agree the shuttles could fly a lot longer but only the govenment can afford it and barely so, and only because they spend tax dollars to keep it flying.If you were to take it and make it a passenger vehicle. You could get more people per flight by converting an old Spacelab or hab module to a passenger carrier.Private interests are working on various solutions such as Scaled Composites Spaceship 2 which itself is suborbital but may lead to an orbital version, and its a winged vehicle. Blue Origins, an SSTO based on the clipper design but a squatter design that has what appears to be better stability. Space "X" favors the rocket capsule approach which might be economically doable in their hands.NASA tried to develop an economical shuttle replacement but NASA budgets are just not high enough to allow successful development as evidenced by the failure to bring about the DC-Y or Venture Star. NASA is back to capsules after nearly two decades pursuing a shuttle replacement.  Posted by qso1</DIV> The only problem withe the Shuttle is it became a political boondogle. If it had been intended to take cargo and personnel to LEO and return cargo and personnel from LEO it would have done ten times the missions it has done so far.What happened is the Airforce addded their requirements, the Shuttle became a vehicle intended for extended missions with large crews, which inveriably led to the ISS, a massive vehicle on the same scale. Shuttle should have been built to reach LEO and deliver cargo and personnel to multiple free-flying Stations and take deep Space or high orbiting payloads into Space cheaper then expendable launchers could do it.  <div class="Discussion_UserSignature"> </div>

nec208 · Apr 7, 2008

In June 2002 NASA extended the Shuttle External Tank contract with Lockheed Martin to September 2008. Under the modified contract, the 35 tanks will be produced at a rate of not less than six per year, versus the eight per year agreed upon in the original contract issued in October 2000.Then went to this link to see how many ETs will be needed to support shuttle missions until retirement. I cannot be certain when the last batch of 35 ETs began to be used and considering the Columbia accident slowed the shuttle flight rate down, there probably will be a few ETs left. -------------------------------------------------------------------------------------- Was Lockheed Martin making any ET for them or onl for the Shuttle ? Does Lockheed  make ET for every space-flight or do the make extra ET if needed? ----------------------------------------------------------------------------------------- I've seen on this board, people who favored capsule designs over winged in the small spaceplane world because they always say bringing wings along is a waste. I don't agree with that view totally because if a winged vehicle can offer robust, economical operation. Seems to me it would be more advantageous than a capsule, especially where cross range maneuvering is a concern. -----------------------------------------------------------------------------------------A rocket is not a object that use the air or parachute like a plane,glider or capsule.A rocket  is a object that has its own propllent and use that .A wing is just that a plane.Or you could have combo plane that is a plane and rocket .A plane is just that it use air to keep up .Take the wing out and it is going down.   <div class="Discussion_UserSignature"> </div>

nec208 · Apr 7, 2008

I can't see anway a vertical landing vehicle could take less propellant then a horizontal powered design.  I mean it looks good in the movies but in reality you have to support the entire weight of the vehicle with propellant from the point you transition from glide to landing. Without vestiagle wings your glide is going to resemble a brick. That intails slowing to zeo forward velocity an descending from there to the surface.   The problem with spaceship taking off vertical and vertical landing like the movies is the power problem.You need 400+ punds of fuel for every 1 pund.The fuel is more weight than the object.The Orbiter weighs 165,000 pounds empty. The external tank weighs 78,100 pounds empty The two solid rocket boosters weigh 185,000 pounds empty eachthen you have to load in the fuel. Each SRB holds 1.1 million pounds of fuel external tank holds 143,000 gallons of liquid oxygen (1,359,000 pounds) and 383,000 gallons of liquid hydrogen (226,000 pounds). The whole vehicle -- shuttle, external tank, solid rocket booster casings and all the fuel -- has a total weight of 4.4 million pounds at launch  4.4 million pounds to get 165,000 pounds in orbit is a pretty big differencehttp://science.howstuffworks.com/rocket2.htmTo the power problem is fixed we have to use boosters and ET with stages.If we found the magic fuel than you can use brick size space-ships like in the movies. Taking of like a plane to altitude x to the rocket is fired is just that a rocket plane.Taking of from a 747 is sitill mot really a rocket. A rocket depence on nothing else out side of the rocket for power.The problem is power.It needs more fuel than the object.------------------------------------------------------------------------------------It might look good in the movies but in reality i won't work. Then factor in lifting off and reaching an orbit, after having landing, with the propellany you brought with you, and it exceeds credibility.  ------------------------------------------------------------------------------------To anti-gravity or the fuel is way less than the object it will be Sci-fi for ever.    <div class="Discussion_UserSignature"> </div>

scottb50 · Apr 7, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>I can't see anway a vertical landing vehicle could take less propellant then a horizontal powered design.  I mean it looks good in the movies but in reality you have to support the entire weight of the vehicle with propellant from the point you transition from glide to landing. Without vestiagle wings your glide is going to resemble a brick. That intails slowing to zeo forward velocity an descending from there to the surface.   The problem with spaceship taking off vertical and vertical landing like the movies is the power problem.You need 400+ punds of fuel for every 1 pund.The fuel is more weight than the object.The Orbiter weighs 165,000 pounds empty. The external tank weighs 78,100 pounds empty The two solid rocket boosters weigh 185,000 pounds empty eachthen you have to load in the fuel. Each SRB holds 1.1 million pounds of fuel external tank holds 143,000 gallons of liquid oxygen (1,359,000 pounds) and 383,000 gallons of liquid hydrogen (226,000 pounds). The whole vehicle -- shuttle, external tank, solid rocket booster casings and all the fuel -- has a total weight of 4.4 million pounds at launch  4.4 million pounds to get 165,000 pounds in orbit is a pretty big differencehttp://science.howstuffworks.com/rocket2.htmTo the power problem is fixed we have to use boosters and ET with stages.If we found the magic fuel than you can use brick size space-ships like in the movies. Taking of like a plane to altitude x to the rocket is fired is just that a rocket plane.Taking of from a 747 is sitill mot really a rocket. A rocket depence on nothing else out side of the rocket for power.The problem is power.It needs more fuel than the object.------------------------------------------------------------------------------------It might look good in the movies but in reality i won't work. Then factor in lifting off and reaching an orbit, after having landing, with the propellany you brought with you, and it exceeds credibility.  ------------------------------------------------------------------------------------To anti-gravity or the fuel is way less than the object it will be Sci-fi for ever.    Posted by nec208</DIV> If you reduce the weight of the vehicle to 60-80,000 pounds, add an upper stage and a couple of turbofan engines then add a wing with landing gear and mounting for SME's and Turbo-jet engines with the ET and SRB assemby attached you could have a flyback, fully reusable First Stage as well as a much safer passenger vehicle. <div class="Discussion_UserSignature"> </div>

qso1 · Apr 8, 2008

The only problem withe the Shuttle is it became a political boondogle. If it had been intended to take cargo and personnel to LEO and return cargo and personnel from LEO it would have done ten times the missions it has done so far.What happened is the Airforce addded their requirements, the Shuttle became a vehicle intended for extended missions with large crews, which inveriably led to the ISS, a massive vehicle on the same scale. Shuttle should have been built to reach LEO and deliver cargo and personnel to multiple free-flying Stations and take deep Space or high orbiting payloads into Space cheaper then expendable launchers could do it. Posted by scottb50Sory for my lengthy delay in replying, been away for a few days. The USAF requirement was certainly one of the problems. As it drove the orbiter to a much larger size and complexity than NASA originally planned for. The other problem is that even when the shuttles design was frozen and work began on it in 1974, it didn't live up to the original traffic model projected for it. This traffic model projected as many as 60 flights annually and had it been able to do that, it would have been far more economical.  <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>

qso1 · Apr 8, 2008

Was Lockheed Martin making any ET for them or onl for the Shuttle ? Does Lockheed  make ET for every space-flight or do the make extra ET if needed?Lockheed Martin builds ETs only for the shuttle because no other vehicle was designed to use them. They build in batches, which means they project for a certain amount of shuttle usage over say, a five year period. They would not normally build with the intent of having extra tanks sitting around but they may have a few if they built more than were actually required. This situation could happen as the shuttle retires. A rocket is not a object that use the air or parachute like a plane,glider or capsule.A rocket  is a object that has its own propllent and use that .A wing is just that a plane.Or you could have combo plane that is a plane and rocket .A plane is just that it use air to keep up .Take the wing out and it is going down.  Posted by nec208[/QUOTE]Thats true. There could be cases in the future where booster rockets would use parachutes to enable recovery and reuse. So far, this has not been implemented as it usually proves impractical.  <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>

qso1 · Apr 8, 2008

Taking of like a plane to altitude x to the rocket is fired is just that a rocket plane.Taking of from a 747 is sitill mot really a rocket. A rocket depence on nothing else out side of the rocket for power.The problem is power.It needs more fuel than the object.Using the vehicle that would be designed to take off from a 747. The portion taking off utilizing rocket engines would technically be considered a rocket. It would simply be a rocket requiring a jet aircraft for a booster as opposed to a first stage rocket booster. Power is certainly the problem and in the cae of a DC-X or SSTO design, power is still the main problem to overcome. To anti-gravity or the fuel is way less than the object it will be Sci-fi for ever.    Posted by nec208Or to use materials in the rocket that are light and strong enough to allow for enough propellant to enable SSTO operations. Can it be done? Only time will tell.  <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>

qso1 · Apr 8, 2008

If you reduce the weight of the vehicle to 60-80,000 pounds, add an upper stage and a couple of turbofan engines then add a wing with landing gear and mounting for SME's and Turbo-jet engines with the ET and SRB assemby attached you could have a flyback, fully reusable First Stage as well as a much safer passenger vehicle. Posted by scottb50Interestingly enough, Rockwell proposed a two stage fully reusable shuttle during phase "A" design studies. No ETs or SRBs were required. One of the first proposals was a study by Lockheed in 1968 which had a "V" shaped drop tank attached to a lifting body vehicle design. The Rockwell proposal was said to have been too expensive to develop but would have been less expensive to operate.This lead to the current design which was less expensive to develop but more expensive to operate. Of course, hind sight being 20/20, the current design proved to be too expensive both ways. I tend to think this would have happened with the fully reuseable system considering the fly back booster was powered by 10 rocket engines. Another booster design featured 12 rocket engines.What I believe was vastly underestimated was the required turnaround maintenance cycle. The idea these vehicles could be turned around for reflight on a biweekly or even monthly basis was simply unrealistic.  <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>

nec208 · Apr 8, 2008

The only problem withe the Shuttle is it became a political boondogle. If it had been intended to take cargo and personnel to LEO and return cargo and personnel from LEO it would have done ten times the missions it has done so far.What happened is the Airforce addded their requirements, the Shuttle became a vehicle intended for extended missions with large crews, which inveriably led to the ISS, a massive vehicle on the same scale. ----------------------------------------------------------------------------------------What is the point of thes shuttle to go up there and back ,  if they cannot stay up there for weeks? And 7 or 8 crews is not much!! What do you want a shuttle of crew of 2 ? And how can they build a space station with out the shttle? <div class="Discussion_UserSignature"> </div>

qso1 · Apr 8, 2008

My view is that the shuttle has been just fine, it has done what we have asked of it so to speak, except provide those services in an economic fashion. The shuttle can be up in space for as much as a couple of weeks, even possibly months when an EDO kit is added. http://en.wikipedia.org/wiki/Extended_Duration_OrbiterThe EDO kit does take up payload bay space but would be useful on missions that require it. Basically the shuttle was to have been nothing more than a truck. A truck for doing just what scottb50 said. Hauling cargo to and from destinations such as space stations.NASA initially planned for a vehicle capable of hauling about 10 tons to low orbit. The USAF wanted a 32 ton capability to orbit. Space station could have been built without the shuttle. Von Brauns 1969 visionary plan was to maintain Saturn-V production for the purpose of hauling large sections of a station to orbit. In the late 1980s, there were plans which made sense to me, to develop an all cargo shuttle then known as shuttle "C". But NASA, ever mindful of budget limitations, decided not to develop shuttle "C".The main problem with the shuttle in building space station is the limits of its payload capacity and payload bay physical size. This means more shuttle flights than what would have been required of an all cargo shuttle.The shuttle should have been limited to ISS crew transport and resupply with some construction tasks that would not require a shuttle "C". Shuttle "C" or some other HLLV equivalent should have been the assembly truck for station. That issue was actually revisited in 1992 or 93 but when the Clinton Admin decided to keep station design pretty much as is, shuttle "C" was history.http://en.wikipedia.org/wiki/Shuttle-C <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>

nec208 · Apr 8, 2008

The shuttle "C was to put big cargo in space and was unmanned shuttle.But they still need a shuttle for space walks and building the space station.Even if the shuttle "C puts the cargo in space than go up in a other shuttle for building it.  <div class="Discussion_UserSignature"> </div>

qso1 · Apr 8, 2008

Absolutely. There would also be times when the shuttle would actually be more economical than shuttle "C". Such as maybe taking up a small robotic manipulator system along with some other payloads, none of which require the payload capacity of a "C" vehicle.The "C" vehicle would have been more economical for the outsized tasks.  <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 8, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Absolutely. There would also be times when the shuttle would actually be more economical than shuttle "C". Such as maybe taking up a small robotic manipulator system along with some other payloads, none of which require the payload capacity of a "C" vehicle.The "C" vehicle would have been more economical for the outsized tasks.  Posted by qso1</DIV>Which is exactly what I was talking about, if you use a large First Stage and a common Second Stage you can attach whatever you want to it. A manned transfer vehicle or a cargo Module could use the same First Stage interchangably. A specific Module for a Station component could just as easily be attached as well as multiple Satellities that would have maneuvering stages to put them in specific orbits.  <div class="Discussion_UserSignature"> </div>

qso1 · Apr 8, 2008

Which is exactly what I was talking about, if you use a large First Stage and a common Second Stage you can attach whatever you want to it. A manned transfer vehicle or a cargo Module could use the same First Stage interchangably. A specific Module for a Station component could just as easily be attached as well as multiple Satellities that would have maneuvering stages to put them in specific orbits.  Posted by scottb50Your talking an LV launched from the ground right?  <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 9, 2008

Your talking an LV launched from the ground right?  Posted by qso1[/QUOTE]I'm talking about a vertically launched First Stage that would use existing Shuttle facilities and have flyback capabilities.The Upper Stage could be various sizes or combined Second and Third Stages as needed for specific payloads. The First Stage would release the Upper Stage at around 80 miles and flyback for landing. The ET/SRB combination would be removed for refurbishment and the wing, or flight section, attached to another stacked ET/SRB, Upper stage(s) and payloads and rolled out to the pad for launch just like the Shuttle. <div class="Discussion_UserSignature"> </div>

qso1 · Apr 9, 2008

Okay, I got it now. And that would be similar to using heavy lifters to do the job of putting outsized station pieces into low orbit. One question I have, how would the ET/STB land. If I understood you correctly, your saying there is a wing attached that enables it to return to a landing?The ET/SRB would have to be very extensivelly redesigned to do that. You also would want to separate at a much lower altitude than 80 miles due to the fact that at 80 miles altitude, you are not far from orbital velocity and likely to be about 1,200 miles down range.This would require a lot of propellant to get the winged ET/SRB back to KSC because of the tremendous forward momentum you would have to overcome to turn from heading east to heading back west to KSC. It would also require the ET portion to have thermal protection for the return since it would be turning back towards KSC and initially heading back at anywhere from 14,000 to 16,500 mph or even slightly higher velocity.Not to mention the structural mods required to allow the ET to have landing gear and support the heavier empty SRB casings upon landing. Most boosters separate at around 25 to 40 miles altitude. The Saturn S1C typically separated 35 to 40 miles altitude and about 6,000 mph. The shuttle SRBs which function as boosters separate at around 30 miles up and 2,800 mph. The lower altitude and velocity in part due to keeping orbiter G loading down.A shuttle "C" would function basically like the shuttle on ascent. Normal SRB sep and eventual recovery or maybe SRB sep at slightly higher velocity and altitude since the "C" vehicle would handle higher G loads better.ET sep about 1,200 miles downrange at a velocity of about 16,750 mph or thereabouts. The ET kept short of orbital velocity while the Shuttle "C" vehicle goes into orbit just as its done on current shuttle ascents. In addition, the shuttle "C" can house an upper stage attached to a payload if required, and in a space station assembly scenario, it probably would be required. <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 9, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Okay, I got it now. And that would be similar to using heavy lifters to do the job of putting outsized station pieces into low orbit. One question I have, how would the ET/STB land. If I understood you correctly, your saying there is a wing attached that enables it to return to a landing?With weight savings from the reduced payload rquirement the wing and associated structure would still give you a Shuttle comparable liftoff weight, turbofan engines could also be used for the liftoff if for no other reason then lifting their weight at that of their fuel. If you consider the weight of an empty, but smaller Et, and lighter weight Carbon filiment wound SRBs and a structural weight of about 60,000 pounds for the wing it would have a landing weight close to a 777.   The ET/SRB would have to be very extensivelly redesigned to do that. You also would want to separate at a much lower altitude than 80 miles due to the fact that at 80 miles altitude, you are not far from orbital velocity and likely to be about 1,200 miles down range.That's why you use an upper stage. Release would be closer to 60 miles and somewhat slower, requiring minimal TPS, downranger requirements would also be reduced with a steeper ascent, but with powered flight capability it would be pretty simple to do. The idea here is a wing structure with a cradle to hold the tank and SRBS. Fairly simple straps would do. The structural requirement of either unit would not be used to support the wing, they would simply sit on top of it with the Upper Stage and payload mounted to the ET the same as it is now.Another alternative is not using the existing ET and using individual cores, propellant tanks and a single engine on each. In this way you could have various configurations, a twin engien light version or a four engine heavy version. I would also think composite construction of both tanks and SRB's would make more sense then using the existing components. On return SRB housings would be reloaded and the tanks refilled for relaunch. This would require a lot of propellant to get the winged ET/SRB back to KSC because of the tremendous forward momentum you would have to overcome to turn from heading east to heading back west to KSC. It would also require the ET portion to have thermal protection for the return since it would be turning back towards KSC and initially heading back at anywhere from 14,000 to 16,500 mph or even slightly higher velocity.Most boosters separate at around 25 to 40 miles altitude.That's why the Upper Stage would be released at a lower altitude and speed. It would also be why the ET would be smaller, it would need less propellant, because the Second Stage actually puts the vehicle into orbit.  A shuttle "C" would function basically like the shuttle on ascent. Normal SRB sep and eventual recovery or maybe SRB sep at slightly higher velocity and altitude since the "C" vehicle would handle higher G loads better.ET sep about 1,200 miles downrange at a velocity of about 16,750 mph or thereabouts. The ET kept short of orbital velocity while the Shuttle "C" vehicle goes into orbit just as its done on current shuttle ascents. In addition, the shuttle "C" can house an upper stage attached to a payload if required, and in a space station assembly scenario, it probably would be required. Posted by qso1</DIV> The problem with the Shuttle C is the same as with the Shuttle. SRB recovery and re-use is a waste of resources, they might be recovered but from what I understand they are usually not suitable for re-use. The ET is discarded and dumped into the ocean. The vehicle is re-usable, but that gets back to the mass fraction equation, it takes 4.4 million pounds to put 165,000 into orbit and that is the amount that is re-usable. If you return closer to 400,000 pounds and only have to add propellant, the cheapest resource needed to launch, it getrs a lot cheaper.  <div class="Discussion_UserSignature"> </div>

qso1 · Apr 10, 2008

With weight savings from the reduced payload rquirement the wing and associated structure would still give you a Shuttle comparable liftoff weight, turbofan engines could also be used for the liftoff if for no other reason then lifting their weight at that of their fuel.The problem I see with this one is not so much weight as it is aerodynamics and structural loading.The idea here is a wing structure with a cradle to hold the tank and SRBS. Fairly simple straps would do. The structural requirement of either unit would not be used to support the wing, they would simply sit on top of it with the Upper Stage and payload mounted to the ET the same as it is now.The above sounds to me like an awful lot of trouble to make existing components work when it would probably be better to start with a clean slate. Another alternative is not using the existing ET and using individual cores, propellant tanks and a single engine on each. In this way you could have various configurations, a twin engien light version or a four engine heavy version. I would also think composite construction of both tanks and SRB's would make more sense then using the existing components. On return SRB housings would be reloaded and the tanks refilled for relaunch.This sounds much better.That's why the Upper Stage would be released at a lower altitude and speed. It would also be why the ET would be smaller, it would need less propellant, because the Second Stage actually puts the vehicle into orbit.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'd say start fresh, the ET/SRB combo is simply not designed to be a Fly Back Booster (FBB).The problem with the Shuttle C is the same as with the Shuttle. SRB recovery and re-use is a waste of resources, they might be recovered but from what I understand they are usually not suitable for re-use. The ET is discarded and dumped into the ocean. The vehicle is re-usable, but that gets back to the mass fraction equation, it takes 4.4 million pounds to put 165,000 into orbit and that is the amount that is re-usable. If you return closer to 400,000 pounds and only have to add propellant, the cheapest resource needed to launch, it getrs a lot cheaper.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.True the ET is discarded but its cheaper to do that than to build the thermal protection and structural strength required to salvage it as far as its present design. The ET could however, be placed in orbit for other uses but there again, it would depend on making the idea economically attractive.The problem that did occur with shuttle "C" is one where the anticipated flight rate was not projected to be high enough to realize economies of scale. Shuttle "C" flight rates of say 4 a year would basically mean shuttle "C" would be as expensive as shuttle if not more so.  <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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