The IIS Express

[marcel_leonard]

Point taken...<br /><br />Keep in mind that just because you can type more than 5 words a minute, doesn't make you a college graduate. One can waste just as much time online, as on air watching cable. Escapism from reality may create more libral artisst, but it will not create more engineers/scientists....<br /><br />For that I would recommend allowing more new college students to test out of their freshmen, and sophmore math/science requirements. Another alternative would be to have more ABET accreditted BS degree programs in Engineering/Science like the following [ie. University of Maryland, Drexel University, and University of North Dakota,] <div class="Discussion_UserSignature"> "A mind is a terrible thing to waste..." </div>

 

[halman]

marcel_leonard,<br /><br />The lackof American engineering graduates is truly a serious matter. However, most of the people that I know who became engineers knew early in high school that they wanted to pursue a career in technology or science, and had begun preparing themselves at that time for the requirements that either field demands, with high school classes in trig, calculus, and physics.<br /><br />If a person has not decided to go that direction until they begin college, they will have a difficult time graduating in 4 years, as they have to build the foundation of a scientific education before they can start taking the advanced science and engineering classes.<br /><br />Engineering seems to me to have become a mystical art to most people, beyond the reach of all but supermen, the ultra geeks who are never considered socially acceptable. I believe that this attitude about the hard sciences is greatly responsible for the lack of people entering the science/engineering fields. The high rate of failure among the lowerclassmen in math and science classes reflects the failure to prepare for these disiplines while still in high school.<br /><br />It is too bad that American football cannot save the world, because America would then be a world leader. Instead, it looks like it is going to take those icky science and engineering types, who make so much money just thinking. It is just not fair! <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>

 

[marcel_leonard]

<font color="yellow">The lackof American engineering graduates is truly a serious matter. However, most of the people that I know who became engineers knew early in high school that they wanted to pursue a career in technology or science, and had begun preparing themselves at that time for the requirements that either field demands, with high school classes in trig, calculus, and physics.</font><br /><br />That is my point exactly: This country doesn't seriously give it's children a college preparatory education. Because of centuries of bias; using the british class system [ie. racism, and placism]...<br /><br />Engineering/Science deaprtments has been "where the action is?" so to speak for the past 300 years, or at least ever since the beginning of the industrial revolution. So I find it very strange, and suspect when the status quo still use the Medieval tactics; of allowing noblity, and clergy to read and write, all the while letting the peasants remain illiterate. So that they remain in their respective places... <div class="Discussion_UserSignature"> "A mind is a terrible thing to waste..." </div>

 

[halman]

marcel_leonard,<br /><br />I believe that the reason that most high schools no longer offer higher math and lab sciences other than biology is the lack of demand. I don't know who to blame for the decline in interest in advanced math and science, but I believe that it has been nation-wide.<br /><br />What you perceive as bias in the educational system I see as systemic faults in the design of the system. The educational system in the United States was never meant to produce scientists or engineers, it was created expressly to meet the demand far factory workers. The goal of educating people to work in a factory environment now is obselete, but the administrators and instructors know of no other way of handling the number of children in the school systems today.<br /><br />I believe that computer technology has the potential to revolutionize education in the United States, if it is used to allow the education system to educate each child seperately, individually. Without some change in the paradigm, we are not likely to see improvement in the results of our efforts to prepare children for the future. <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>

 

[marcel_leonard]

<font color="yellow">The educational system in the United States was never meant to produce scientists or engineers, it was created expressly to meet the demand far factory workers.</font><br /><br />This is what I mean by "Placism"[keep them in there place]. This form governing rule has been w/ us since biblical times. The difference is that we now have more literate men/women on this planet; then in the history of mankind. I'll give you an example: Two high school students graduate in May of 2004. One attends the University of Michigan for the next 4 years. The other buys the Microsoft Certified Systems Engineering exam preparartion book, than after a few weeks takes/passes the exam. The first student hasn't completed his first semester of college before the other student lands a job as a MCSE making 64k annually...<br /><br />The moral to the story is that our current educational systems is doing a piss poor job of keeping up w/ the way technology is effecting our society... <div class="Discussion_UserSignature"> "A mind is a terrible thing to waste..." </div>

 

[fatjoe]

<font color="red">halman-<br />I believe that the reason that most high schools no longer offer higher math and lab sciences other than biology is the lack of demand. I don't know who to blame for the decline in interest in advanced math and science, but I believe that it has been nation-wide</font><br /><br />I think part of the blame has to be placed on the local/state departments of education. Ever since the civil rights movement of the 50s local/state governments waste allot of time and money fixing the blame and not the problem. It is known fact that in the south, and some parts of the north; state officials practice "seperate but equal" standards in the public school system. We are simply deal w/ the symptoms of an illness that was never cured.<br /><br />If we want to develope more rocket scientist who may some day create an affordable delivery system into outer space; we will first have to stop practice the Ghost of Jim Crow; which still exist in our municipalities.

 

[halman]

FatJoe,<br /><br />Certainly there is no denying that school systems across the country treat schools in minority areas differently, and prejudice is still strong in many areas. But I still maintain that the fundamental structure of our eductatian system, the class system, is no longer effective. Not only are there huge numbers of students who graduate who are functionally illiterate, but the number of students who are dropping out of school is an order of magnitude greater than what it was 20 years ago.<br /><br />Personally, I believe that large amounts of video, whether it be television, video games, or movies, alters the way that people learn. Video is constantly changing, which requires assimilating information very rapidly by visual means. Teaching today is based on listening, with only a small reliance on visual aids. But listening to the spoken word is no longer a common skill, in spite of thousands of years of cultural reliance on the oral tradition.<br /><br />Only in the United States are children exposed to hours of television every day. This has made children in this country extremely fast in learning visually. Our education system has refused to acknowledge that anything has changed, with results which constantly create demand for more spending on education. Without changing the system, more money is going to have little effect, I believe. <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>

 

[marcel_leonard]

Then we should adopt a more visual way of teaching students. Along w/ more online ABET acreditted degree programs should solve this problem cost effectly.<br /><br />Not to change the subject; but while I was working on assignment for an online course, at the same time running Windows Media Player, and RealPlayer I happen to catch a demonstration on NASA-TV on magnetic rocket propulsion, or plasma propulsion. Does anyone of an actual plasma rocket engine that is actually being tested? <div class="Discussion_UserSignature"> "A mind is a terrible thing to waste..." </div>

 

[marcel_leonard]

Senate report on new transport the ISS <div class="Discussion_UserSignature"> "A mind is a terrible thing to waste..." </div>

 

[halman]

marcel_leonard,<br /><br />A change of subject is welcome, as we are flogging a dead horse, as the saying goes.<br /><br />Plasma propulsion systems are infernally difficult to study on Earth, as they only will work in a vacum. This is the type of work many had hoped would be undertaken on the International Space Station, as creating a large enough evacuated area to test an engine on Earth is difficult and expensive.<br /><br />However, theoretical work has gone forward, at labs all over the country. There was an interesting thread about an advanced propulsion system on this board about a week ago. I believe that it was a hot-hydrogen rocket, which derived its power from a nuclear pile. I will see if I can find it and create a link. <br /><br /> <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>

 

[halman]

marcel_leonard,<br /><br />see "P&W Triton nuclear engine"<br /><br />Someday, I have just got to learn html. <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>

 

[marcel_leonard]

Actually ever since SpaceShipOne reached LEO, and re-entered the atmosphere w/ out over heating due to Burt Rutans new Feather technology. I was thinking that a re-engineered X-43A scramjet built w/ new carbon composites/ Feather technology could finally achieve LEO, and eliminate over heating in re-entry.... <div class="Discussion_UserSignature"> "A mind is a terrible thing to waste..." </div>

 

[nacnud]

SSO is sub orbital and didn't reach Low Earth Orbit, which is why it didn't overheat on the way back down.

 

[marcel_leonard]

Overheating is caused by the material travelling at extreme velocities into Air pressure. It has nothing to do with how high it went, or whether or not it left the atmosphere. If a 747 travelled at mach 10 through the jet stream long enough it would overheat.<br /><br />My point was The Rutan Feather could be adapted for the super sonic LEO flight to reduce the overheating of re-entry... <div class="Discussion_UserSignature"> "A mind is a terrible thing to waste..." </div>

 

[nacnud]

I agree but remember that orbital velocity is around mach 25 and that SSO only reached mach 3 or so. Energy goes up with the square of velocity so by my crude calculations that means that an orbital craft has to loose about 70 times the energy that SSO had to on re-entry.<br /><br />I don't know if you can realistically apply Rutans brilliant feather design to such a different situation.<br />

 

[halman]

marcel_leonard,<br /><br />You may have fallen in to the same trap that many others have been caught by: Going into space and going into orbit are not neccessarily the same thing.<br /><br />Going into orbit means pointing the nose at the horizon and stepping on the gas until you are traveling around 18,000 miles per hour, or 5 MILES PER SECOND, to use the vernacular.<br /><br />Going into space is as simple as climbing straight up until you have reached 100 kilometers, or 62 miles. (Whichever comes first.) Coming straight down, you travel about as fast as you did going up, if you are flying in SpaceShip One, about Mach 3, or about 2,200 miles per hour, which is only about .6 miles per second.<br /><br />The 'feather' feature of SpaceShip One helped to keep its airspeed down, but it also assured that the vehicle would be in a nose-down attitude when the atmosphere became thick enough to cause damage from buffeting, as well as velocity. It is a brilliant innovation, but has no application to orbital re-entry, (I believe,) where the huge velocity of orbital travel, plus additional velocity caused by falling toward the planet, must be dissipated somehow.<br /><br />SpaceShip One got hot, it is true, but only for a few moments, and only a fraction of a percent as hot as the shuttle. SpaceShip One was in greater danger of breaking up due to buffeting than it was of burning up. If it hit atmosphere at the wrong attitude, (orientation, such as upside down with the nose pointing up,) the turbulance would tear it apart in seconds as the atmosphere got thicker. <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>

 

[marcel_leonard]

<font color="yellow">You may have fallen in to the same trap that many others have been caught by: Going into space and going into orbit are not neccessarily the same thing. </font><br /><br />Since you don't think the Feather technology would be useful; what other techniques would you recommend to slow down re-entry? <div class="Discussion_UserSignature"> "A mind is a terrible thing to waste..." </div>

 

[halman]

marcel_leonard,<br /><br />Strangely enough, I was thinking about this exact subject recently.<br /><br />Given all the attention being showered upon carbon nanotubes in relation to extremely long tethers, I was considering the idea of a 'space anchor.'<br /><br />A vehicle in a circular orbit at an altitude of, say 100 miles, deploys a sled, which has retro rockets on it. This sled is attached to the vehicle by a tether 20 to 30 miles in length. The sled fires the retro rockets, and the tether is allowed to spool out. After the sled has dropped several miles in altitude, it deploys winglets, which turn it into an inverted lifting body. The inverted lifting body exerts a downward force on the tether, while slowing itself in velocity. Before the tether has been completely spooled out, the reel is brought to a stop, and locked. The sled is piloted remotely from the vehicle to produce the optimum drag, while holding altitude, until the velocity of the vehicle has been diminished to the point where it is entering atmosphere. Then, the reel is unlocked, and the tether reeled in, while at the same time the sled is increasing the drag.<br /><br />The idea is to seperate the vehicle from the heat energy created by slowing its velocity. The sled, being a fairly light device, can radiate that energy quickly into the surrounding space. There would be a few details to work out, (chuckle,) but it could work, I think. <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>

 

[marcel_leonard]

Why not just have jumper retro-fitted rockets mounted on the base of the vehicle [Imagine the next generation of ScramJet/AeroSpike space shuttle w/ such a deceleration device] to control its decent? <br /><br /> <div class="Discussion_UserSignature"> "A mind is a terrible thing to waste..." </div>

 

[halman]

marcel_leonard,<br /><br />Short of using the same amount of energy to slow the vehicle down that was used to put it in orbit, aerobraking is the only way to deaccelerate. Aerobraking produces heat, which is what softened up Columbia to the point where atmospheric resistance destroyed the vehicle. Tethering the orbiter to a device which performs the aerobraking seperates the orbiter from the heat. <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>

 

[halman]

marcel_leonard,<br /><br />On rereading your last post, I realized that I probably mis-understood you the first time.<br /><br />One of the limitations of the system that I propose is the strength of the tether. In order for it to be light enough to be hauled into orbit, it cannot be strong enough to handle more than a few thousand pounds of stress. However, that is still adequate to slow a vehicle down enough to lower its orbit. <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>

 

[marcel_leonard]

What exactly was it that you mis-understood? <div class="Discussion_UserSignature"> "A mind is a terrible thing to waste..." </div>

 

[halman]

marcel_leonard,<br /><br />I am not sure if you are talking about putting some kind of rocket engines on the orbiter, or on the 'anchor sled'.<br /><br />The whole purpose of aerobraking is to lose velocity without using propellant. The enourmous kinetic energy of moving 5 miles per second, which takes several million pounds of propellant to acheive, has to be bled off somehow. Using rockets to get rid of this energy means the payload of the launch is the re-entry rockets.<br /><br />The shuttle is exposed to temperatures of thousands of degrees while it is moving through the upper atmosphere, as the resistance of the atmosphere to the passage of the shuttle is translated into heat. Finding a way to slow the shuttle with aerobraking without exposing it to the plasma-like temperatures is why I am proposing some kind of tethered airfoil that can transmit the change in velocity via a cable.<br /><br />We have been discussing tethers many miles in length on this forum for some time, including one which would be nearly 100 miles long, for the Earth Orbiting Elevator. A tether used for that application would have to be able to support thousands of pounds. A cable 40 or 50 miles long, which is designed to handle 10,000 pounds of pull, might be able to gradually slow the orbiter while the orbiter is still outside the part of the atmosphere which is dense enough to perform aerobraking, if the cable is attached to a lifting body shape which is inverted, so that the lift pushes the lifting body down, instead of holding it up.<br /><br />The anchor would be flown below and behind the orbiter, far enough into the atmosphere to allow aerobraking, while the orbiter was still above the atmoshere. As the orbiter's velocity is reduced, it will drop further into the atmosphere. At the same time, the attitude of the anchor is changed to increase the drag. Because the anchor has no sensitive cargo, it can be exposed to much higher internal temperatures safely, which means that it can slow <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>

 

[marcel_leonard]

Would'nt retro-fitting compressed air on to a new shuttle design achieve the same amount of aerobraking? The compressed air, or gas could be jettisoned as it lowered in the the atmosphere... <div class="Discussion_UserSignature"> "A mind is a terrible thing to waste..." </div>

 

[halman]

marcel_leonard,<br /><br />The whole concept of aerobraking is to use what is naturally available to save weight. Hauling any kind of reaction mass into orbit in order to get back down is to be avoided. If you are in orbit around the Moon, or Mercury, then you must cancel all of your velocity with rocket power. Earth and Mars (Venus, too, if anyone cares,) both have adequate atmospheres for aerobraking.<br /><br />This saves having to haul millions of pounds of propellant into orbit, which is dead weight, until time for re-entry. Having some kind of heat sheild, or Thermal Protection System, allows the vehicle to be slowed by air resistance alone. The drawback is that the vehicle is exposed to temperatures as high as 12,000 degrees F. for a few minutes during the descent, which has to be prevented from touching the structural part of the vehicle. Ballistic re-entry vehicles use what is known as an ablative heat sheild, which literally burns away, carrying the heat that is absorbed with the chunks of heat shield which break off.<br /><br />This system would not work for the shuttle, for various reasons, so a new method had to be developd. The thermal tiles coating the shuttle are able to absorb incredible amounts of heat without transfering that heat through the material. The tiles gradually radiate the heat off over a period of several hours, at a very low surface temperature. Any flaw in the TPS or heat sheild will allow the plasma-range temperatures to affect the vehicle, which is what happeneod to the Columbia.<br /><br />My 'space anchor' concept is a way to use aerobraking without exposing the vehicle to the high temperatures, if it could work, and if we had carbon nanotube technolgy. Using carbon nanotubes, a cable 40 miles in length, yet strong enough to withstand thousands of pounds of strain, would weigh only a few hundred, or maybe a couple of thousands of pounds. The anchor sled would probably weigh about 1500 pounds, at most. <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>