Pros and cons with DC-X and other LVs.

nec208 · Mar 26, 2008

The DC-X was never designed to achieve orbital altitudes or velocity, but instead to demonstrate the concept of vertical take off and landing. The vertical take off and landing concept was popular in science fiction films from the 1950's (Rocketship XM, Destination Moon, and others), but not seen in real world designs. It would take off vertically like standard rockets, but also land vertically with the nose up. This design used attitude control thrusters and retro rockets to control the descent, allowing the craft to begin reentry nose-first, but then roll around and touch down on landing struts at its base. The craft could be refueled where it landed, and take off again from exactly the same position — a trait that allowed unprecedented turnaround times.In theory a base-first re-entry profile would be easier to arrange. The base of the craft would already need some level of heat protection to survive the engine exhaust, so adding "more" protection would be easy enough. More importantly, the base of the craft is much larger than the nose area, leading to lower peak temperatures as the heat load is spread out over a larger area. Finally, this profile would not require the spacecraft to "flip around" for landing. Pictures here.http://www.fas.org/spp/guide/usa/launch/dc-x-ac96-0363_a.jpg <div class="Discussion_UserSignature"> </div>

qso1 · Mar 26, 2008

The DCX was as you mentioned, a prototype for demonstrating the concept. Had DCX continued, it was to have lead to the DCY in the late 1990s which would have been the orbital demonstrator. Unfortunately, the Venture Star was chosen over the DCX. This when the DCX had several flight tests under its belt and the VS was just computer graphics. The Venture Star terminated when propellant tank development problems stalled its development. Jeff Bezos and company are developing a Single Stage To Orbit (SSTO) SSTO based on the DCX. Its a squatter version of the DCX which actually may give it better vertical stability. Sooner or later, SSTOs will probably become operational. Especially if Bezos and his team succeed with their SSTO.http://public.blueorigin.com/index.html <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 · Mar 26, 2008

The DCX was as you mentioned, a prototype for demonstrating the concept. Had DCX continued, it was to have lead to the DCY in the late 1990s which would have been the orbital demonstrator. Unfortunately, the Venture Star was chosen over the DCX. This when the DCX had several flight tests under its belt and the VS was just computer graphics. The Venture Star terminated when propellant tank development problems stalled its development.------------------------------------------------------------------------------------------I believe it was NASA and government doing research into the DCX ,Venture Star ,x-33 and other x projects, to they ran out of money do to budget cuts and long with some engineering problems.So now it seems the private sector is doing research into it.So may be they will fix those engineering problems. <div class="Discussion_UserSignature"> </div>

qso1 · Mar 26, 2008

Your right, it was a government program. The DCX began as a Strategic Defense Initiative Office (SDIO) program as part of the Reagan era star wars plan. In the early 1990s, NASA under Administrator Dan Goldin picked up the program when the SDIO lost interest or couldn't continue funding it. When NASA took it, the program was grouped under the general X designation of X-33. X-33 covered the DCX and the Venture Star as only one was to win the competition to build a robust shuttle follow on vehicle. The decision to go with the Venture Star was made in 1996 IIRC so work on the DCX ceased after that.Your also right about the engineering problems. In addition to the tank problem, there is the difficulty of building a vehicle light enough to lift itself and propellant to orbit and yet be strong enough for robust reliable operation. This is why current rockets must ascend in stages.Private industry may solve this problem now that the materials technology is reaching a point where single stage to orbit may be possible and even practical. If that happens, expendables will finally be history tho it may take overlapping operation of both types for awhile to see that actually occur.  <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 · Mar 26, 2008

So really any rocket has to be 2 or more stage .A rocket using only one stage is just too heavy. But why can't they put the x-33 on a 2 or 3 stage rocket .And because the DC-X is small and only one stage  than how will it work?   <div class="Discussion_UserSignature"> </div>

qso1 · Mar 26, 2008

Correct, current rockets have to be in stages. An SSTO can be part of such a system. A DCX for example, could be modified to sit atop a booster stage and be part of what is known as a 2 stage to orbit or 2STO design. The Venture Star would be a lot more difficult to adapt to a booster, at least in the vertical booster world due to the Venture Stars wide butt.It would also be difficult to mount it on back of say, a 747 because the 747 couldn't carry it with its propellant load. Even if it could carry it, the vehicle likely would not have enough energy to reach orbit. However, a much smaller version of Venture Star on back of a 747 might work.  <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>

Swampcat · Mar 26, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Correct, current rockets have to be in stages. An SSTO can be part of such a system. Posted by qso1</DIV> Technically speaking, an SSTO consists of one stage. The acronym stands for Single Stage to Orbit.Also, rockets do not have to have more than one stage. Of course, if you want to make it to orbit or even significant suborbital altitude, especially with a payload <img src="http://sitelife.space.com/ver1.0/content/scripts/tinymce/plugins/emotions/images/smiley-wink.gif" border="0" alt="Wink" title="Wink" />, current technology requires more than one stage. <div class="Discussion_UserSignature"> ------------------------------------------------------------------- "I hold it that a little rebellion now and then is a good thing, and as necessary in the political world as storms in the physical. Unsuccessful rebellions, indeed, generally establish the encroachments on the rights of the people which have produced them. An observation of this truth should render honest republican governors so mild in their punishment of rebellions as not to discourage them too much. It is a medicine necessary for the sound health of government."Thomas Jefferson </div>

qso1 · Mar 27, 2008

Technically speaking, an SSTO consists of one stage. The acronym stands for Single Stage to Orbit.Thats why I mentioned it would be a 2STO at that point.Also, rockets do not have to have more than one stage. Of course, if you want to make it to orbit or even significant suborbital altitude, especially with a payload , current technology requires more than one stage. Posted by SwampcatCorrect, if your firing a bottle rocket in your back yard, a single stage rocket is fine. Want to go to orbit, currently multi stage is the only way until some entity finally cracks the SSTO barrier.  <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>

Swampcat · Mar 27, 2008

"Thats why I mentioned it would be a 2STO at that point.Also, rockets do not have to have more than one stage." --qso1Gotcha. I didn't follow what you wrote. My bad. <img src="http://sitelife.space.com/ver1.0/content/scripts/tinymce/plugins/emotions/images/smiley-embarassed.gif" border="0" alt="Embarassed" title="Embarassed" /> <div class="Discussion_UserSignature"> ------------------------------------------------------------------- "I hold it that a little rebellion now and then is a good thing, and as necessary in the political world as storms in the physical. Unsuccessful rebellions, indeed, generally establish the encroachments on the rights of the people which have produced them. An observation of this truth should render honest republican governors so mild in their punishment of rebellions as not to discourage them too much. It is a medicine necessary for the sound health of government."Thomas Jefferson </div>

qso1 · Mar 27, 2008

No sweat, I actually had to check to see if I wrote it to be sure I did. <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>

pmn1 · Mar 28, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>So really any rocket has to be 2 or more stage .A rocket using only one stage is just too heavy. But why can't they put the x-33 on a 2 or 3 stage rocket .And because the DC-X is small and only one stage  than how will it work?   Posted by nec208</DIV>Space Island Group have suggested it for a DC-X type vehicle, whether they do it is very debatable.http://www.spaceislandgroup.com/dual-launch.html <div class="Discussion_UserSignature"> </div>

qso1 · Mar 28, 2008

They got some good ideas but they have been around for awhile and so far no signs any of these ideas are materializing. A DCX type vehicle could also serve as the basis for a lunar SSTO or one for mars operations. The Blue Origin Goddard vehicle could be well suited for those roles because its wider at the base and not so tall which should result in better vertical stability.  <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 · Mar 28, 2008

Our first goal at the Space Island Group (SIG), when it was incorporated in California in late 1999, was to use non-government funds to finance the design, construction, launch and operation of very large commercial space stations built from a re-engineered version of the space shuttle's orange, hollow external fuel tank, or ET. Our second goal was to design, build, launch and operate transport vehicles to move large numbers of people up to these stations and back down to Earth.This is a variation of the DC-X (or 'Delta Clipper') single-stage-to-orbit (SSTO) design developed by Dr. Bill Gaubatz and his team at McDonnell Douglas in the early 1990s. The original concept was to place enough liquid oxygen/liquid hydrogen fuel inside the vehicle to let it reach orbit without external fuel tanks or rocket boosters, or perhaps with just a single, small booster rocket. When its orbital task was completed it was to re-enter the atmosphere nose-first, rotate to a tail-first position a few thousand feet above the landing site, then land gently as the retro-rockets in its tail fired. Its design and operating costs were to be a small fraction of the space shuttles. A prototype was built and this landing concept and cost structure was successfully proven, but in the mid-90's the program's federal funding ran out ------------------------------------------------------------------------------------------------  I sounds like Space Island Group will like private companies to give them money and they will do it. <div class="Discussion_UserSignature"> </div>

qso1 · Mar 29, 2008

Several things would have to happen. One of which would be for NASA to agree to send tanks into stable storage orbits where they could remain for years until work could begin on refurbing them. This would require putting a system on the ET for each shuttle flight that would get them to orbit and with but a few shuttle flights left, this idea probably wouldn't fly with NASA.Another would be to show tanks really are economically viable for this use as opposed to say, Bigelow inflatable modules.   <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 · Mar 30, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Several things would have to happen. One of which would be for NASA to agree to send tanks into stable storage orbits where they could remain for years until work could begin on refurbing them. This would require putting a system on the ET for each shuttle flight that would get them to orbit and with but a few shuttle flights left, this idea probably wouldn't fly with NASA.Another would be to show tanks really are economically viable for this use as opposed to say, Bigelow inflatable modules.   Posted by qso1</DIV> They are just saying they want to re-engineer the space shuttle's orange tanks. <div class="Discussion_UserSignature"> </div>

qso1 · Mar 31, 2008

They are just saying they want to re-engineer the space shuttle's orange tanks. Posted by nec208I assume you mean SIG wants to re-engineer the tanks. Problem is, there will only be a few tanks left to support the remaining shuttle flights before the production line is converted to ET derived booster stages for the Ares 1 and V.For SIG to be able to do any ET orbiting, they would have to get NASA to keep shuttle ETs in production and the shuttle in service to get any future tanks to orbit.  <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>

spacelifejunkie · Mar 31, 2008

Space Island Group has little to no chance of ever being successful.  Every prediction they have made has GROSSLY come up short.  Gene Myers (CEO) was on The Space Show about a year and a half ago claiming they were on the verge of a $10,000,000,000 deal with China, India, and Japan for research into Solar Powered Satellites.  That's right, ten billion dollars (Dr. Evil inspired quote<img src="http://sitelife.space.com/ver1.0/content/scripts/tinymce/plugins/emotions/images/smiley-wink.gif" border="0" alt="Wink" title="Wink" />).  I wish everyone luck but I'll start believing in SIG when I see something fly.  Blue Origin, Armadillo Aerospace, and Masten Aerospace should be considered long before SIG for any craft that takes off and lands vertically. SLJ

qso1 · Mar 31, 2008

Blue Origin, Armadillo Aerospace, and Masten Aerospace should be considered long before SIG for any craft that takes off and lands vertically. SLJ Posted by spacelifejunkieI agree 100%. Iv'e seen plenty of great looking CGI from SIG but thats about it..  <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 · Mar 31, 2008

They are giving that money to China ? or those countries giving them money?Why work on solar power?  <div class="Discussion_UserSignature"> </div>

nec208 · Apr 1, 2008

For SIG to be able to do any ET orbiting, they would have to get NASA to keep shuttle ETs in production and the shuttle in service to get any future tanks to orbit. ---------------------------------------------------------------------------------------What they saying is they are going to build space stations built from a re-engineered ET.How they going get up there by the Dual-ET vehicle . We calculated that re-designing the ETs and building our first unmanned 'Dual-ET' vehicle would cost about $2 billion and take 3-4 years. It would have one fuel-filled ET with engines at its lower end, and space shuttle solid rocket boosters attached to its sides. Mounted on the side of this first ET, between the (2) boosters would be a second, empty ET that could carry cargo to orbit, or its interior could be outfitted in advance as living and working quarters for at least a dozen people. The space shuttle is not needed the Dual-ET vehicle will put it in space.I'm sure NASA has many ET laying around.   <div class="Discussion_UserSignature"> </div>

scottb50 · Apr 1, 2008

We calculated that re-designing the ETs and building our first unmanned 'Dual-ET' vehicle would cost about $2 billion and take 3-4 years. It would have one fuel-filled ET with engines at its lower end, and space shuttle solid rocket boosters attached to its sides. Mounted on the side of this first ET, between the (2) boosters would be a second, empty ET that could carry cargo to orbit, or its interior could be outfitted in advance as living and working quarters for at least a dozen people. The space shuttle is not needed the Dual-ET vehicle will put it in space...I wold think it would be something of a problem to just slap on engines to the lower end of a ET. Also with a side mounted ET payload would be limited by the need to control the vehicle withe the main and SRB nozzles.  <div class="Discussion_UserSignature"> </div>

qso1 · Apr 1, 2008

The space shuttle is not needed the Dual-ET vehicle will put it in space.I'm sure NASA has many ET laying around. Posted by nec208I posted an excerpt from the link immediatly below: http://www.globalsecurity.org/space/facility/michoud.htmIn 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. http://www.sworld.com.au/steven/space/shuttle/manifest.txt13 flights left and 11 from the June 2002 announcement total 24 tanks left but this would only be if the contract tanks started being used right after contract announcement. If SIG actually enters into contractual agreements, then it might be possible to pick up a few ETs after the shuttle is shut down.But they still would require tank production to continue in order to actually build some of the stuff I saw on their site and this in turn would require contracts with the current ET builder Lockmart (Lockheed Martin). Or SIG would have to build ETs on their own which would make no sense once the shuttle is done.At that point, you may as well start from scratch.But my main point is this. Just because it looks easy does not mean it is. How much will it actually cost to reuse ETs once the logistics of on orbit outfitting are really better understood? If its such a great idea, why hasn't it already been done? This idea of putting ETs in orbit to be used for space station habs, etc was around long before SIG came along.Consider SIG and the Bigelow inflatable hab efforts. SIG is still doing nothing more than presenting concepts. Bigelow already has two test habs in orbit. I don't see how reused ETs can compete with inflatables at this point. <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 1, 2008

Most of SIG's space hardware will come directly from NASA's space shuttle program. The shuttle's main engines, its fuel tanks and its white solid rocket boosters will lift SIG's space station components into orbit. The shuffle itself will not be used at this time. SIG will carry personnel to orbit and back aboard another manned vehicle which was designed and tested by NASA and the Air Force a decade ago. It was called the Delta Clipper, or DC-X. By 2010 SIG's first "Orbital Clippers" will carry 30 people up on each flight and return them to Earth safely. Later versions will carry over 100.These two passages direct from SIGs website are telling. Start with the hardware coming from the shuttle program. Particularly the SSMEs. Does SIG think its going to get some huge surplus of SSMEs? or do they plan to take over manufacture of SSMEs.SSMEs are not cost effective engines anyway. Very labor intensive and require practically an overhaul after each use. But look at the line about orbital clippers. By 2010, they will carry 30 people? Yet there is no sign that this vehicle is being tested as would be required by now to make a 2010 or even a 2012 operational status.Theres no sign the vehicle even exists beyond the CGI illustrations.Now its possible the company has kept it under wraps but at the very least, it would have to say or show a little more just to demonstrate credibility to potential investors. Burt Rutan and Scaled Composites kept Spaceship 1 under wraps pretty well but when one looks at scaleds history. There is tangible evidence that company can deliver.Maybe SIG will produce actual hardware yet, but I'm bettin its not gonna happen.  <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>

pmn1 · Apr 1, 2008

Would putting a DC-X type vehicle on top of a stack be a viable option in making part of the system reusable? <div class="Discussion_UserSignature"> </div>

qso1 · Apr 2, 2008

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.  <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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