The IIS Express

[mrmorris]

<font color="yellow">"I predict that the ESA will pick up where the french left off."</font><br /><br />You need to change the water in your Magic 8-Ball. <br /><br />Read the whole Astronautix post on the Hermes. It was rapidly going the way of the US shuttle, with costs ballooning rapidly. Until there is a need, and a capability to launch at rates near to what was originally predicted for the Shuttle (40 flights a year if I recall correctly), an RLV of this type is not cost-effective.<br /><br />The needs of ESA that would be answered by a Hermes-style craft would be better resolved by the use of a small CEV-style shuttle, or Soyuz-stype capsule. Ariane can lift their cargos -- they just need a means to send people to orbit. <br /><br />Like the shuttle, the Hermes would be unlikely to do anything more than LEO. A smaller manned vehicle that was not designed to carry cargo would possibly be upgradeable for HEO use or potentially even lunar missions.<br /><br />For reducing the costs of sending cargo to orbit -- their 'Hopper' concept mentioned earlier might well work. It at least has the <b>possibility</b> of launching cargo at rates below that of ELVs.

 

[marcel_leonard]

Actually I think Britian's developing a fixed wing spacecraft for emergency evacuation of the ISS <div class="Discussion_UserSignature"> "A mind is a terrible thing to waste..." </div>

 

[nacnud]

Looks a bit sophisticated to me... still in the unlikely event of it being too advanced for current UK tech you could stick a plunger to the front and sell it to the BBC props dept for the upcoming new Dr Who series.

 

[marcel_leonard]

But think of the all saving they'll have by building it using the metric system, and off the self parts. <div class="Discussion_UserSignature"> "A mind is a terrible thing to waste..." </div>

 

[mrmorris]

<font color="yellow">"...Britian's developing a fixed wing spacecraft..."</font><br /><br />I don't see any place labeled on the schematics to put the frog.

 

[nacnud]

Do loofahs come in metric sizes? <br /><br /><font color="yellow">and off the shelf parts</font><br /><br />Surly you mean shelf parts <img src="/images/icons/smile.gif" />

 

[mrmorris]

<font color="yellow">"Surly you mean shelf parts"</font><br /><br />Indeed -- the finished product looks like it contains parts salvaged from one or more shelves.<br /><br />...and there's no need to call Marcel 'Surly'.

 

[marcel_leonard]

Surly you jest? Even Skakespear didn't speak liketh thoust... <div class="Discussion_UserSignature"> "A mind is a terrible thing to waste..." </div>

 

[halman]

marcel_leonard,<br /><br />Since no one provided a definition to the term 'escape velocity', I thought I might have a go at it. The 'velocity of escape' is the speed which needs to be traveled in a direction parallel to the surface of a body to be able to escape the gravitational influence of that body. If you wish to 'escape from Earth', you must aquire a velocity relative to the surface of 25,000 miles per hour. Anything less, and you eventually will be pulled back into an orbit around the planet.<br /><br />So, if you are in orbit around the Earth at 18,000 miles per hour, and you wish to go to Mars, you must accelerate to at LEAST 25,000 miles per hour to break away from the Earth. Now, you will lose almost all of that velocity before you escape the planet's gavitational field, which means to reach the orbit of Mars, you will have to be traveling at 26,000 mph, or more.<br /><br />The escape velocity of the Moon is only 5,300 mph, which is why using materials from the Moon to build space stations is so appealing. Building a magnetic launcher capable of sending payloads of several tons past the Lunar escape velocity seems fairly feasible. <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>

 

[spacester]

<font color="yellow">Since no one provided a definition to the term 'escape velocity' . . . </font><br /><br />??????????????????<br /><br />Try reviewing the thread again . . . . <br /><br />Hint: look for posts by some guy named spacester, with a paragraph beginning with "Escape velocity defined . . . "<br /><br /><img src="/images/icons/rolleyes.gif" /> <div class="Discussion_UserSignature"> </div>

 

[fatjoe]

Anyway you look at it all comes down to the fuel, and the energy needed to reach these velocities. My guess is nuclear and EM propulsion are the way to go. I think for the past 35 years we've being wasting our time with this old heavy lift technology.<br /><br />Kinda like the way scientist have developed;l through sign laungage a way to teach great apes how to do simple mathematics; yet through out our nation's public school system of K-12 children aren't being introduced to algebra/geometry/trigonometry/calculus until there last four years of school!<br /><br />No wonder we have the world's largest prison population. We design it into the system!

 

[marcel_leonard]

Not to worry Joe; they say "The Truth Shall Set You Free!"<br /><br />Once enough people realize this we will be free to roam around the galaxies.... <div class="Discussion_UserSignature"> "A mind is a terrible thing to waste..." </div>

 

[halman]

spacester,<br /><br />I apologize. I was misled by the first two paragraphs of the post in question. However, after rereading said post, I am hesitant to say that your definition is relevant. I do not have ANY doubt that it is both precise and completely accurate, but I have never seen escape velocity defined in such a way.<br /><br />I consider myself to be a layman in regards to space flight. I have some understanding of the theory or the concepts involved, but I lack the mathamatical skills required for a thorough understanding of all the aspects involved. In a similiar fashion, I have grasped the underlying theory of nuclear physics, chemistry, mechanics, and several other subjects which require math to be defined in an expert fashion.<br /><br />Because I did not see a definition of escape velocity which had meaning for me, I attempted to provide one, in the belief that there are others, who, while interested in technical subjects, share my handicap of a lack of knowledge or skill with math.<br /><br />Again, I apologize for my slight. <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>

 

[spacester]

halman, apology accepted. I suppose I owe you one myself. I have been getting more frustrated than usual here lately. There seems to be a trend where people ask a question but are not interested in the answer.<br /><br />As I tried to explain, escape velocity is a mathematical abstraction. If you want to understand orbital mechanics at any level, escape velocity is NOT the place to start.<br /><br />I tried to provide a definition which can be visualized. But as an abstract concept, IMO the definition cannot be both accurate and enlightening.<br /><br />I get the distinct impression that everyone's eyes glaze over as soon as they see an equation.<br /><br />The math is not that hard. Really, it's not! If you can understand those subjects without any math, my compliments. Orbital mechanics is just algebra for the most part, and you don't need to do anything more than put numbers in for the variables and punch some numbers into a calculator, at least to get started. I have a hard time believing that is so hard.<br /><br />In all my years here, with all the equations I've posted, I do not recall even one time when someone said, "ah, that's interesting, if I take your equation but use different numbers, I come to the following conclusion . . ." Not once!<br /><br />I guess folks want wisdom without any effort on their part. To me that is just too weird to accept, but that's what I have to conclude. <div class="Discussion_UserSignature"> </div>

 

[nacnud]

<font color="yellow">In all my years here, with all the equations I've posted, I do not recall even one time when someone said, "ah, that's interesting, if I take your equation but use different numbers, I come to the following conclusion . . ." Not once! </font><br /><br />Don't give up! I would prefer to use equations in some of my posts but I find that ASCII text is probably the worst format for trying to display maths I have ever seen, <img src="/images/icons/frown.gif" />. Added to this going from skim reading a post to trying to extract the meaning from a hard to read equation and it always seems easier just to jump the maths and carry on hand waving, I normally make a mental note to come back and check the maths properly, but I never do. Pity really.<br />

 

[mrmorris]

<font color="yellow">"I guess folks want wisdom without any effort on their part. To me that is just too weird to accept, but that's what I have to conclude. "</font><br /><br />In general -- people want *everything* to come without sacrifice. Some really twisted people actually *enjoy* the effort involved in learning something new (Guilty). Others actually enjoy the act of jogging (Not guilty). If the effort involved in doing something isn't enjoyable, then someone has to be willing to make a sacrifice if they're interested in the end result. Someone who doesn't enjoy learning, but <b>does</b> enjoy being knowledgeable will often take the time to learn. Likewise someone who hates jogging, but wants to be in shape might well run a couple miles a day.<br /><br />So -- I don't see what you're describing as weird -- just sad.<br /><br />Just to be pedantic -- 'wisdom' is the wrong word. Wisdom has little to do with knowing a fact or being ignorant of same. You can call this knowledge, information, data, etc. <br /><br />Wisdom is more a matter of having foresight -- generally acquired by the painful memories of hindsight. This is why old people are generally considered wise -- they have lots of hindsight to apply towards the decision-making process. People who are wise before their time are often those who have done more than their fair share of stupid things while young -- and therefore have built up a good stock of hindsight at an early age... <img src="/images/icons/smile.gif" /> <br /><br /><br />P.S. The people who do more than their fair share of stupid things while young and *don't* get wise at an early age <b>also</b> have a name. They're called stupid people.

 

[halman]

spacester,<br /><br />The original post in this thread speaks to concept that I have seen brought up repeatedly on this board, i.e. using a method of imparting substantial velocity to a spacecraft while still on the ground. The way the question was framed, I had the impression that it was in reference to launching from the Moon.<br /><br />Because the Moon is an airless body, with a low gravity, it would be an excellent location to build a magnetic launcher. But someone took off on the tangent that magnetic launching is impossible on Earth, due to the atmospheric drag. So what seemed like a promising discussion regarding a major goal in the development of the Moon degenerated into a comedy routine about levitating a frog!<br /><br />I do not fault the inquiry and exposition displayed in this thread, but I share the sense of frustration that you have mentioned.<br /><br />To build a magnetic launcher on the Moon, a tremendous amount of energy will have to be made available for use in a short period of time. How should this energy be stored? Solar power can provide the required energy over a period of time, but the amount needed for accelerating a payload of several thousand kilograms to a velocity of 9000 kilometers per hour would require collecting the sunlight falling on the majority of the sunlit face of the Moon if direct solar energy were to be used.<br /><br />Some people have suggested using large flywheels, spun up over days or weeks. How effcient is the conversion of electrical enery to mechanical, and then back to electrical? The Moon does not seem to have large amounts of heavy metals, which would seem to be a requirement of building flywheels. Capacitors are capable of discharging very quickly, but the size of the capaitor bank needed to generate sufficient power is staggering, and capacitors tend to leak when they are near fully charged.<br /><br />Would it be better to build a nuclear reactor for providing the enegy, which is only put in high output mode du <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>

 

[spacester]

Thanks for the encouragement, fellas, I won't give up just yet. <br /><br />halman, nice post, you are of course correct on my mis-use of the word wisdom. Lol, I don't know how many times I've tried to point out the difference between wisdom and intelligence and knowledge. Not so much here, as in real life. People often look at me funny when I do that, but I'm used to it. <img src="/images/icons/laugh.gif" /><br /><br />The irony of having that explained to me is just too amusing for words. I was trying to be diplomatic . . . I tried a series of words before I came up with 'weird', then failed to use 'knowledge' instead of 'wisdom'.<br /> <div class="Discussion_UserSignature"> </div>

 

[halman]

spacester,<br /><br />Now I are all confuseded. I never said anything about your use of word 'wisdom'. I long time think you very wise! <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>

 

[spacester]

Ooooops, I think I'm losing it. For some reason I thought mrmorris' post was from you . . . <div class="Discussion_UserSignature"> </div>

 

[nacnud]

<font color="yellow">To build a magnetic launcher on the Moon, a tremendous amount of energy will have to be made available for use in a short period of time. How should this energy be stored?</font><br /><br />A similar problem was experienced in the US Army's Rail Gun or electromagnetic gun proposal. They have managed to address the problem by storing the energy mechanically and converting that energy very quickly to electrical energy. The mechanical energy is provide through a take-off from the vehicles engine. Do you think such technology could be adapted to use in your Luna linear accelerator?<br /><br />From spacedaily.com,<br /><br /><b>US Army Issues Electromagnetic Gun Program Contract</b><br /><br />Roseland NJ (SPX) Jul 29, 2004<br /><br />Curtiss-Wright Corporation was awarded a 36-month, $30.8 million contract for the design, development, build and test of a compact pulsed power supply in support of the US Army's Electromagnetic Gun (EM gun) Technology Maturation and Demonstration program. Curtiss-Wright's Flow Control segment will act as prime contractor with responsibility for the overall machine design.<br /><br />As the first step in the progression towards a fully field able electromagnetic weapon system, the pulsed power supply is a key component of EM gun technology envisioned to be part of the weapon systems of the future. Beyond the initial three-year technology demonstration program, the program presents significant additional development opportunities for all aspects of the EM Gun through the next decade.<br /><br />The Pulsed Power Supply (PPS) consists of two counter-rotating machines capable of supporting the high power density requirements necessary to achieve target defeat using kinetic energy projectiles launched at high speed.<br /><br />The use of pulsed power involves the storage of energy mechanically and converting it on demand to electrical energy

 

[mrmorris]

<font color="yellow">"The way the question was framed, I had the impression that it was in reference to launching from the Moon."</font><br /><br />Kinda-sorta. He talks about mining the moon and asteroids -- but then talks about the mass of the earth and the escape velocity thereof. At the very least, if he was talking about a moon-based launcher -- his post was unnecessarily confusing.<br /><br /><br /><font color="yellow">"Because the Moon is an airless body, with a low gravity, it would be an excellent location to build a magnetic launcher. But someone took off on the tangent that magnetic launching is impossible on Earth, due to the atmospheric drag."</font><br /><br />I agree -- the moon would be an excellent location for a maglev/railgun. However -- for the reasons above -- I don't think any tangent was involved. In any event -- if Marcel had meant the moon -- he could have corrected the direction of the thread by saying so early on. Instead his posts were directed towards defending Earth-launched payloads via a railgun -- specifically indicating that high-temperature materials could be used to make it feasible. If, as you indicate, he truly had meant for his railgun to be based on the moon -- this would be a very unusual thing for him to do.<br /><br /><font color="yellow">"So what seemed like a promising discussion regarding a major goal in the development of the Moon degenerated into a comedy routine about levitating a frog!"</font><br /><br />The moon was never mentioned at all after the first post -- so no <i>discussion</i> about 'development of the moon' ever occurred. Also -- if you'll recheck the posts -- you'll note that the Marcel wrote both the original post *and* brought up the frog initially. If you truly think that the frog post was deserving of more reasoned discussion, I'd be <b>very</b> interested to hear your thoughts on the application of magnetically levitated frogs towards the advancement of spaceflight.<br />

 

[marcel_leonard]

<font color="yellow">The moon was never mentioned at all after the first post -- so no discussion about 'development of the moon' ever occurred. Also -- if you'll recheck the posts -- you'll note that the Marcel wrote both the original post *and* brought up the frog initially. If you truly think that the frog post was deserving of more reasoned discussion, I'd be very interested to hear your thoughts on the application of magnetically levitated frogs towards the advancement of spaceflight. </font><br /><br />Once again your very long reply still doesn't change the fact that w/ enough Magnetic force you can cancell out Gravitational force, [Fg = m a = q v B]....<br /><br />The way I see the problem we really don't know enough about either force at this point to make maglev space travel possible. sapientia- which in latin means [-ae f. [wisdom , good sense, discernment]; esp. [proficiency in philosophy, science, etc.], physicus -a -um [relating to physics , physical]; m. as subst. [a scientist]; n. pl. physica -orum, [physics]; adv. physice, [in the manner of scientists]. is the reason why still study the things which we don not understand. This is understanding/wisdom that you simply can't get just by earning a diploma... <div class="Discussion_UserSignature"> "A mind is a terrible thing to waste..." </div>

 

[mrmorris]

<font color="yellow">"Once again your very long reply still doesn't change the fact that w/ enough Magnetic force you can cancell out Gravitational force..."</font><br /><br />Since most of my post was in support of the physics of a lunar railgun -- yet you're arguing using magnestism to 'cencel out' grapvity -- I have to assume we're back to levitating frogs again. I'm not going there again. <br /><br />It may well be possible at some point in the distant future to use magnetism in such a fashion. This is a homework project for you -- figure out how to do it -- throw a few amphibians into orbit, then come back to the board and tell us how it's done. Right now -- the notion is firmly in the realm of science fiction. We study all *kinds* of things that we don't understand -- this is known as basic science. However -- basic science is not intended to produce useable discoveries, that would be applied science. Even applied science can take decades to produce a result that has any use outside of a laboratory (e.g. nuclear fusion). <br /><br />To make plans based around a concept such as your magnetic levitation isn't wise, discerning, or sensible. Instead it falls under a different latin root word: dementia - n. [L., fr. demens. See Dement.] Insanity; madness; esp. that form which consists in weakness or total loss of thought and reason; mental imbecility; idiocy.<br /><br />

 

[halman]

nacnud,<br /><br />The article you cite is marvelously ambiguous regarding the exact nature of the machines used to store energy, saying only that they are "counter-rotating". This suggests to me that they are using flywheels, which is an excellent way to store energy, as long as they are on the surface of a body large enough not to be affected by the gyroscopic forces involved in rapidly spinning objects. <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>