actually, GP is right. If he weren't, we would simply use electric coils to heat up air. Note that we don't do this. We burn a hydrocarbon product in air, which produces many molocules of gas -- more molecules means more of something else:
p*v = n*R*T; T (temp) and n (number of moles of gas) went up, so p (pressure) or v (volume), or both, must also increase. R (Rydbergs constant) is a constant.
Yes, but when you consider a long haul trucker, getting 4 miles to the gallon and driving 10 hours a day at 60 (HAHAHAH) mph, you get 600 miles a day
600 mi/day * 1/4*Gal/mi = 150 gallons of fuel a day.
10% = 15 gallons a day saved
Assume 5 days a week of driving, average, for a year
75 gal per week, or 3900 gal per year, saved.
diesel is cheaper, but still assume 2.50 a gallon
9750 dollars.
And the article said that the MOST EXPENSIVE unit will be 7500 bucks. The implication being that the cheaper models would be priced to make sense to the average car owner -- e.g. the family that is still pissed at dad for buying a masculinized mini-van right before U.S. gas prices finally adjusted themselves to fit reality.
Assume 30mpg, average. 18 thousand miles a year (average in US, IIRC) = 600 gallons total fuel per year.
so, 60 gal * 3.00/gal = 180 dollars.
Life span of device = 7 years. But people won't buy it if it doesn't amortize over 3 years, so it will either have to cost less than 400 bucks, installed, be legally required... or gas prices will have to hit 8 bucks a gallon;~)
As for the target buyer 'average buyer' above, the savings is more like
25,000 miles per year / 12mpg * 10% * $3.00 per gal ~= $625/year.
In 3 years that is $1875, in 7 years it is $4375.
Besides, it's Canadian; that 7500 CAN is like the price of a dinner and a movie down here;~)
Qmail : a small office of neatly dressed clerks, delivering short clipped remarks to queries, and handling mail with a rude impersonality, except in the case of failiure where they let their hair down and have an after-hours beer and let you know about it, pointing to the pertinent header sections.
MMDF: A jumped up mailroom boy with a chip on his shoulder. Loves the bureaucracy and takes great pride in stamping "illegal address" in red ink on any mail it passes. Unpacks all the mail and repacks it in his own special envelopes before delivery to end users.
PP: MMDF gone mad with standards fever. Think "Brazil".
No, PP is... well, see, when it receives a letter, it chops it into small pieces, then translates bits of it using an English-Hungarian phrasebook and puts all the bits into various pigeon-holes. When it gets round to delivering the message, it collects all the bits, translates them back using a Hungarian-English phrasebook, tapes them together, and loses the letter. Some time later, you get a bounce message:
----- The following addresses had permanent fatal errors -----
----- Transcript of session follows -----... while talking to bloat.example.com.: >>> RCPT To:
550 My hovercraft is full of eels
PP is John Cleese.
Sendmail: Shiva as a postman. Many arms delivering mail, dancing, taking drugs, destroying as it sees fit. Often makes creative changes to the mail for kicks, but ultimately can be persuaded to do anything with the right incantation...and that includes giving you other people's mail.
VMail: No experience yet, but I'd guess something like a wisened old man sitting on the porch outside the postoffice. Looks at everyone who passes by with deep suspicion, but turns out to be friendly and helpful once he realises you're not there to rob the place.
Micro$oft IMC: The Scarlet Pimpernel of postmen. Hard to find, impossible to order about, but every once in a while it saves a piece of mail from disaster. Sometimes even with it's head(ers) intact.
cc:Mail SMTPLINK: A 5 year old child left in charge of a large sorting office. Can't reach over the counter properly, can't handle more than one letter at once and has to go looking for a grownup whenever it wants to deliver to mail to other towns. Often opens parcels to look for shiney things inside then just delivers the wrapping paper onwards.
cc:mail UUCPLINK: an insane madman sitting in a box. Mail is thrown into a box where unknown things happen to it.. sometimes mail actually leaves the box.. usually to be delivered to the administrator of a totally unrelated postoffice and containing a complaint that the madman could not find the recipient in his dark box and would you please contact the person with the key of the box. Of course, the only way to reach that person is by mail and even if the box is opened the madman cannot be pursuaded to actually send mail to unknown addressees to the person with the key anyway... Gus, Pete Bentley, Malcolm Ray, Perry Rovers
If you own a car in running condition, it gets stolen and your name is on the title (definition of 'own' there, really), you will be named in the lawsuit, should said car get in a wreck/kill a child whatever.
Maintain insurance on all vehicles which you own, if you have any assets to protect.
Reality: IQ is real, it measures something related to reasoning.
'Something'
What something?
I do not disagree that there are aspects of intellect which are real and (somewhat) quantifiable. This is obvious. Some people can't figure out how to change a tire, literally to save their life (e.g. they kill themselves by doing it wrong). Others can seem to figure anything out, in moments.
Where I disagree is on the tests. There is simply no way to assign a specific number to an induhvidual and say 'this is how smart you are, compared to everyone else'.
There are just too many types of 'smarts'. I believe I am highly qualified to state this, as I graduated with an 'average' GPA for my class (engineering, undergrad level), and my last IQ test (SAT) showed me to be in the top 1%. I know smart... and I know stupid. And we are all smart and stupid in dozens of ways.
I also have some relatives who score incredibly low on standardized tests. They are both dyslexic, but that wasn't known at the time they were crowned with the title of 'slow'. The title hurt them more than the dyslexia.
IQ tests, as such, CANNOT WORK. They are a desperate attempt to mechanize something which isn't even fully understood by those who would claim the right to define 'intelligence'.
All they do is show, statistically, that a certain percent of humanity fits into a specific pattern. By definition no IQ test can correctly measure the IQ of anyone who is not average.
As has been said in one form or another by many, many people, all of whom are completely correct: 'IQ tests only show how well you did on that particular IQ test'.
When you show me an IQ test that includes taking apart and re-assembling a carburetor, and getting a stubbern child to go to bed on time, then maybe we will be getting somewhere.
To the credit of the few who understand the actual point of standardized tests, THEY don't insist that the test has any meaning out side of its narrowly defined intent. E.g. The SAT is used to predict how well a certain person will TEND to fair in their first year at university. It isn't all that great at it either. It is just a hell of a lot easier than reading all those essays, and interviewing all those potential students.
Had four or five that never solved -- all sine/cosine functions multiple lines (of written text) long. Didn't say unsolvable, just ran and ran and ran, until I started not caring any more:~)
And that is using 's1,c1,s2,c2...' etc instead of (sin(a), sin(b)) etc.:~)
Wasn't shocked to not get an answer.
And yeah, I am hoping to hear of a 'suped up' 89 one of these days. Maybe I should check out the HP, but damn I would hate to have to get used to yet another input device;~)
not sure about the 84, but the 89 uses a motorola MC68000 12Mhz part.
I have personally had problems take more than 30 minutes to solve on the 89. Plotted ODEs which took 10 minutes to refresh, etc. Things that didn't matter enough to break out the cursed Matlab.
More common, using a solve function on a rotation matrix can take a few seconds (more than 10, less than 60), but is something I commonly do with the calculator.
The 89 is actually as powerful as most thousand+ dollar math packages. Matlab requires an expensive plugin to do explicit, and it SUCKS at it (okay, entering values sucks, the solver is fine). And so on. It is just plotting that sucks, as.... well, thats a damned small screen:~)
I addressed all of your points above 'via simple dropship' in previous posts along this thread.
SO, jumping into the statement regarding GEO potential energy. 100% correct. You have a lot of potential energy. You also have a huge amount of kinetic energy. In the wrong direction. General rule of thumb for orbits: Speed up, go up. Slow down, go down. Which is why, if you ever found yourself in the same orbit as the ISS, but 2 miles behind it, you would die if you aimed for it and burned your engine -- you would go into a higher orbit and 'slow down' WRT to the station. You actually need to aim AWAY from the station, drop into a lower orbit, which is FASTER (you cover more radians per second along the arc), and then when you are in position, 'speed up' again, to take you up to the ISS.
The only way your gravitation potential energy means anything is when you are 'falling down' a guided path; your rotational motion must be restricted. E.g. you are attached to the elevator cable.
Getting from a 800km orbit to a 40,000 km orbit (~geo) takes exactly as much energy as getting from a 40,000km orbit to an 800km orbit. Matter of fact, I would bet that anybody trying to get home from geosync would actually go into a lunar flyby orbit and re-enter that way; probably cheaper than the change in eccentricty required to make your perigee low enough to slow you into a capture. Because I am bored and don't do this enough:
rp = 6378km + 200km = 6578km ra = GEO = 42,164 km a = 1/2(ra + rp) = 24371km v = root(2*mu*(1/r-1/(2*a))) mu_earth = G*Me = 3.986E5 km^3/s^2
v with (r = rp) = 10.2km/s
With an apogee of 370km (that of the ISS, IIRC): rp = 6378km + 200km = 6578km ra = 6378km + 370km = 6748km a = 1/2(ra + rp) = 6663km v = root(2*mu*(1/r-1/(2*a))) mu_earth = G*Me = 3.986E5 km^3/s^2
v with (r = rp) = 7.882km/s
The Apollo (lunar) reentry speeds were in the range of 11.1 km/s.
So even IF you make no attempt to circularize your orbit first, you STILL only add ~2km/s to your re-entry speed -- about 30%. It makes a difference, but it isn't that big of a deal. And if it is? Circularize your orbit first.
As to finicky, the Space Shuttles heat sheild is a finicky device; heat shields in general are rather well understood. Honestly, how you can even begin to compare a heat shield to an engine (which you implicitly do, in your final paragraph) I cannot begin to fathom.
Size is not a big deal at all, in this case, as there is certainly no WAY we will be getting even close to the size of the space shuttle, which, while not exactly a shining example, is obviously 'doable'. Realistically the logical thing to do would be use a typical tear-drop design, which has most certainly proven itself in practice.
I simply cannot understand why people CARE if it is one way or two way? As far as PEOPLE are concerned (as 'cargo'), using a shuttle to get back will be FASTER. By like a WEEK. As far as materials, once again, tell me ONE thing that you would actually NOT want on a space station? Any raw mass is useful. Once our technology improves, I imagine even human wastes would be put to some use, rather than being shot towards the sun.
Design the 'disposable' climbers correctly, and you can integrate virtually all of the craft into the growing orbital station. Are there some highly-specific actuators that you can't manage to find a use for on orbit? Pack them in a box and send them earthside via a return craft. And your arguement that the heat shield tech is 'finicky' followed by a conclusion that 'you might as well just build rockets'...well, surely you recognize the contradiction.
The problem with our current system is that we Americans insist on doing everything the 'super high tech' way. It isn't elegant, it is failure prone, and it isn't cost effective. 'Cheap' is a relative term. Jet fuel isn't 'cheap' either, but a 747 can burn over 300 thousand pounds of it in one flight. And make a profit.
My understanding There is no real way to gain back any significant energy without making the system completely impossible to build within the foreseeable future. So we gain no energy by returning.
So, if you gain no energy by returning, you don't want to USE energy (and space, and the mass of the 'passing' systems etc) to return!
So you use super simple cargo craft that are disposable. Remember, if it has valuable components (solar panels, metals) it isn't just going to be pitched out the window! The craft will be in space; those panels will be added to the station, or they will be put to use on some satellite. Nothing is going to be 'thrown away'.
For the more complex craft, if there are any (people movers, maybe?) you store them at the upper station in some collapsed form, and once a month or whatever you send them back planet side via a simple dropship -- just a cargo hold an a heat shield, basically.
Really, my thought on the matter is that humanity cannot yet see a day when we will not need/want to keep every spec of mass that comes up in space, for use on (whatever). We are at LEAST a couple of decades away from digging minerals out of the lunar surface or dragging an asteriod back to mine. Perhaps even a century or more from doing so.
And as for PEOPLE -- current plans don't include them as using the elevator, if I recall (which is sad), but if/when people start using the system, then there would be small, simple return ships every few days. Though getting BACK to earth from Geo would be a real bastard. I suppose one could use pure electric propulsion system though, which would help -- use magnetic drag to slow down. In 20 years we should have the super-conducting materials we would need to make it a reasonable trip, though I'm only daydreaming here.
Oh yeah, and the power thing. I almost wonder if the space elevator would be a major driver of fusion power:~) MAN is it going to suck electrons:~)
And yeah, the travel time will likely be few days. So what? You can get to LEO in a matter of hours once everything has been built out and systems put in place to deal with any whiplash effects that jumping off before the steady-state altitude.
Finally, advantage of capturing energy: again, completely off base with respect to the current design considerations. It would be a LOT cheaper ( I estimate at least by a factor of ten, but that is just a guess) to take high energy fuel up to the anchor mass (at the end of the tethor), than to design the system to actually allow both up and down capabilities.
And even if you HAVE a down capability, that by no means implies that you can capture the potential energy of a decending object. Recall that it is a 'rope', not a bar. And the rope is already in tension. I can see no solution which would allow you to gather any worthwhile amount of energy. You can't run a current through the elevator, as you would then have a stupendeous amount of magnetic drag thanks to Earths magnetic field. So no electromagnetic regen. Which doesn't matter, as *any* form of draggy braking against the cable just looks like more mass to be lifted from the perspective of the anchor mass.
If it were a solid bar than the shift of mass would do the job on its own, thanks to the whole inertia game. If we used a 'dangling rope' and litterally tied the 'Low end' to a mass, lifted it into space and then dropped it back down, you could also get the energy back, minus drag.
In summary, your entire post strikes me as pure opinion, with no basis in fact. If I am mistaken, I urge you to issue some form of defense. While I commend you for caring, I believe that you do a disservice by attacking something you don't understand, while pretending, or worse assuming, that you do.
It is a multi-body problem. Generally solved using a whole bunch of pieces of software, just to check;~)
I've never heard of using multiple 3-body systems. I did this stuff in college not to long ago, so, while I'm not saying it isn't done....;~) (*NOT* a Masters degree, just bachelors. Which is like working the McDonalds grill for a year and then trying to get a job as a master chef).
The way we did it (again, as undergrads) was some pretty raw itterative brute force. We did a lot of happy math, don't get me wrong, but the body of the work is done by progs like STK (http://www.stk.com/) from analytical graphics.
It is possible to get a ball park using some happy math tricks. Not enough to really model the trajectory, but enough to say 'oh, I'm going to need a deltaV of 'x' km/s' and you will have a good idea of your error margin (e.g. 'x' +/- 5%). We did these for a number of trajectories as homework problems; a few hours each, pencil paper only. Well, some of use;~) I abused my TI-89 horribly:~)
If a company wants a particular item to NOT go through a tunnel when shipping via rail, it can be generally be made to work out. It is a pretty robust network, our railroad system. Could be better, but it isn't bad, considering.
Anyway, the SRBs are 12.2 feet in diameter, whereas the typical rail-car width is somewhere around 10 feet. Tunnels with only 1.5 feet of extra clearance on each side? Somehow I doubt it.
I have no idea what extra packing is done -- might increase the diameter slightly.
Anyway, not something real high on my 'things to care about list'. Just bored and being a pest;~)
the closer to the equator you are, the less energy you need to expend to get into space as you can use the earth's rotational velocity to propel you up there. So you have less fuel or more cargo
You've got part of the story. The real deal is that the minimum energy required to get into an orbit with inclination (x) comes when you launch from the LATITUDE of x, thus taking off due east.
Failing that, launching from some latitude LESS THAN the desired inclination, and launching at the angle (above a line parallel to the equator) which is the same as the desired inclination is generally pretty close to above (5% losses).
So, if you launch from 28 deg. latitude you can get into any orbit with an inclination from 28 to 90 degrees (polar) by simply 'aiming' (aligning the launch vector) along the ground track of you desired orbit (e.g. want a 45 deg. inclination? Launch 45 degrees counter-clockwise from due East). Getting to an inclination of 28 degrees requires that you launch at an angle of... due East.
But if you want to get into an orbit with an inclination of say 20 degrees, and you are launching from Florida.. you can't. I mean that 100%. It is NOT POSSIBLE to get into an orbit lower than your launch latitude WITHOUT an on-orbit maneuver. You MUST get into an orbit (which will generally be the same as your launch latitude, 'cause that is cheapest) and then, once there, 'crank' your orbit down, by firing thrusters. Usually, if one was FORCED to do a plane-change, it would be done in two steps (three, if you count launching as one): first, get into a highly elliptical orbit with a high apogee. Second, fire the plane change burns at apogee. Third (optional but usual) circularize the orbit again.
Grab a marker and an orange, it is easy to see how it all works.
And afternoon thunderstorms pretty much everyday for a good part of the year.
I admit I am highly biased against Houston:~) Stepped off a plane in early august and about passed out. And heat is a big deal for gliders.
And regarding working with an existing space port, there is no way in hell Rutan would do it. I just can't see it happening. Why? Because he doesn't build anything that NEEDS that kind of infrastructure. So a good chunk of his space rent would be paying for things that he wouldn't use.
Anyway, I also admit I've no better ideas. Personally, I'd bet a dollar that they will open a couple of sites. What would rock is if they offered flights between them:~).
Hm. Interesting thought. I'll bet two dollars that within 10 years after starting up tourist flights they will offer direct flights to/from Europe. Could be simple hope, to be honest;~)
Things like this will help with what is called 'peaking power'. No need to spool up a couple of gas turbines in the middle of the day when you build one of these.
Coal plants are run 24/7 in most cases (base load). Ditto nuke. Mostly this type of tech will remove gas from the mix. I'd bet dollars to donuts that the utilities will be selling or using this power as redundancy rather than 'open market' power. Which is to say, they won't need to hold a contract with another company (or buy another gas turbine) in order to meet their required reliablity rating. Plus they will be able to offer it up as a source of renewable to those who check the little box that says 'I'll pay extra...' etc.
Slashdot Mirror
actually, GP is right. If he weren't, we would simply use electric coils to heat up air. Note that we don't do this. We burn a hydrocarbon product in air, which produces many molocules of gas -- more molecules means more of something else:
p*v = n*R*T; T (temp) and n (number of moles of gas) went up, so p (pressure) or v (volume), or both, must also increase. R (Rydbergs constant) is a constant.
Yes, but when you consider a long haul trucker, getting 4 miles to the gallon and driving 10 hours a day at 60 (HAHAHAH) mph, you get 600 miles a day
;~)
;~)
600 mi/day * 1/4*Gal/mi = 150 gallons of fuel a day.
10% = 15 gallons a day saved
Assume 5 days a week of driving, average, for a year
75 gal per week, or 3900 gal per year, saved.
diesel is cheaper, but still assume 2.50 a gallon
9750 dollars.
And the article said that the MOST EXPENSIVE unit will be 7500 bucks. The implication being that the cheaper models would be priced to make sense to the average car owner -- e.g. the family that is still pissed at dad for buying a masculinized mini-van right before U.S. gas prices finally adjusted themselves to fit reality.
Assume 30mpg, average. 18 thousand miles a year (average in US, IIRC) = 600 gallons total fuel per year.
so, 60 gal * 3.00/gal = 180 dollars.
Life span of device = 7 years. But people won't buy it if it doesn't amortize over 3 years, so it will either have to cost less than 400 bucks, installed, be legally required... or gas prices will have to hit 8 bucks a gallon
As for the target buyer 'average buyer' above, the savings is more like
25,000 miles per year / 12mpg * 10% * $3.00 per gal ~= $625/year.
In 3 years that is $1875, in 7 years it is $4375.
Besides, it's Canadian; that 7500 CAN is like the price of a dinner and a movie down here
An 80 dollar book.
"Lotus Notes for Dummies" is surely a single page pull out with "don't" printed on it.
t ml
Unknown
http://home.xnet.com/~raven/Sysadmin/ASR.Quotes.h
From ASR ( http://home.xnet.com/~raven/Sysadmin/ASR.Quotes.ht ml )
... while talking to bloat.example.com.:
Re : Mail Transfer Agents
Qmail : a small office of neatly dressed clerks, delivering short clipped remarks to queries, and handling mail with a rude impersonality, except in the case of failiure where they let their hair down and have an after-hours beer and let you know about it, pointing to the pertinent header sections.
MMDF: A jumped up mailroom boy with a chip on his shoulder. Loves the bureaucracy and takes great pride in stamping "illegal address" in red ink on any mail it passes. Unpacks all the mail and repacks it in his own special envelopes before delivery to end users.
PP: MMDF gone mad with standards fever. Think "Brazil".
No, PP is... well, see, when it receives a letter, it chops it into small pieces, then translates bits of it using an English-Hungarian phrasebook and puts all the bits into various pigeon-holes. When it gets round to delivering the message, it collects all the bits, translates them back using a Hungarian-English phrasebook, tapes them together, and loses the letter. Some time later, you get a bounce message:
----- The following addresses had permanent fatal errors -----
----- Transcript of session follows -----
>>> RCPT To:
550 My hovercraft is full of eels
PP is John Cleese.
Sendmail: Shiva as a postman. Many arms delivering mail, dancing, taking drugs, destroying as it sees fit. Often makes creative changes to the mail for kicks, but ultimately can be persuaded to do anything with the right incantation...and that includes giving you other people's mail.
VMail: No experience yet, but I'd guess something like a wisened old man sitting on the porch outside the postoffice. Looks at everyone who passes by with deep suspicion, but turns out to be friendly and helpful once he realises you're not there to rob the place.
Micro$oft IMC: The Scarlet Pimpernel of postmen. Hard to find, impossible to order about, but every once in a while it saves a piece of mail from disaster. Sometimes even with it's head(ers) intact.
cc:Mail SMTPLINK: A 5 year old child left in charge of a large sorting office. Can't reach over the counter properly, can't handle more than one letter at once and has to go looking for a grownup whenever it wants to deliver to mail to other towns. Often opens parcels to look for shiney things inside then just delivers the wrapping paper onwards.
cc:mail UUCPLINK: an insane madman sitting in a box. Mail is thrown into a box where unknown things happen to it.. sometimes mail actually leaves the box.. usually to be delivered to the administrator of a totally unrelated postoffice and containing a complaint that the madman could not find the recipient in his dark box and would you please contact the person with the key of the box. Of course, the only way to reach that person is by mail and even if the box is opened the madman cannot be pursuaded to actually send mail to unknown addressees to the person with the key anyway...
Gus, Pete Bentley, Malcolm Ray, Perry Rovers
On the other hand, when was the last time you heard anyone talking about a Microsoft product in anything but a lament?
;~)
OneNote is incredible.
What company did they buy to get it? Anyone?
Any highway starts with 'the'
The 10
the 5
the goddamned parking lot.
It is part of being in SoCal.
Oregon law stops defining financial tickets for speeds greater than 25 over, and starts declaring jail time.
You WILL go to jail if you are caught going 100+ mph. Will. Unless you talk *real* smooth.
California, at least near Riverside, it is 'required' that you be booked for anything over 100, and your car towed.
I recall nothing about lost licenses. That is actually the one thing that is almost impossible in the US.
Yes. Sick, isn't it?
If you own a car in running condition, it gets stolen and your name is on the title (definition of 'own' there, really), you will be named in the lawsuit, should said car get in a wreck/kill a child whatever.
Maintain insurance on all vehicles which you own, if you have any assets to protect.
Reality: IQ is real, it measures something related to reasoning.
'Something'
What something?
I do not disagree that there are aspects of intellect which are real and (somewhat) quantifiable. This is obvious. Some people can't figure out how to change a tire, literally to save their life (e.g. they kill themselves by doing it wrong). Others can seem to figure anything out, in moments.
Where I disagree is on the tests. There is simply no way to assign a specific number to an induhvidual and say 'this is how smart you are, compared to everyone else'.
There are just too many types of 'smarts'. I believe I am highly qualified to state this, as I graduated with an 'average' GPA for my class (engineering, undergrad level), and my last IQ test (SAT) showed me to be in the top 1%. I know smart... and I know stupid. And we are all smart and stupid in dozens of ways.
I also have some relatives who score incredibly low on standardized tests. They are both dyslexic, but that wasn't known at the time they were crowned with the title of 'slow'. The title hurt them more than the dyslexia.
IQ tests, as such, CANNOT WORK. They are a desperate attempt to mechanize something which isn't even fully understood by those who would claim the right to define 'intelligence'.
All they do is show, statistically, that a certain percent of humanity fits into a specific pattern. By definition no IQ test can correctly measure the IQ of anyone who is not average.
As has been said in one form or another by many, many people, all of whom are completely correct: 'IQ tests only show how well you did on that particular IQ test'.
When you show me an IQ test that includes taking apart and re-assembling a carburetor, and getting a stubbern child to go to bed on time, then maybe we will be getting somewhere.
To the credit of the few who understand the actual point of standardized tests, THEY don't insist that the test has any meaning out side of its narrowly defined intent. E.g. The SAT is used to predict how well a certain person will TEND to fair in their first year at university. It isn't all that great at it either. It is just a hell of a lot easier than reading all those essays, and interviewing all those potential students.
I.Q. tests designed by middle-class white males show that white middle-class males are smarter than everyone else!
Averages are BS, IQ tests are BS.... Beh. Yet another notch in the belt for those fuckheads who shove GI Joe at boys and Barbie at girls.
'Math is hard!'
vs
'... and knowing is half the battle'
Who was encouraged to do what again? We are somehow surprised at differences in the sexes BASED ON CURRENT OUR SOCIAL SITUATION?
Bah.
Had four or five that never solved -- all sine/cosine functions multiple lines (of written text) long. Didn't say unsolvable, just ran and ran and ran, until I started not caring any more :~)
:~)
;~)
And that is using 's1,c1,s2,c2...' etc instead of (sin(a), sin(b)) etc.
Wasn't shocked to not get an answer.
And yeah, I am hoping to hear of a 'suped up' 89 one of these days. Maybe I should check out the HP, but damn I would hate to have to get used to yet another input device
Cheers
What I want is a 'keyboard' mod -- turn the TI-89 into a keyboard HID :~)
That would rock.
not sure about the 84, but the 89 uses a motorola MC68000 12Mhz part.
:~)
I have personally had problems take more than 30 minutes to solve on the 89. Plotted ODEs which took 10 minutes to refresh, etc. Things that didn't matter enough to break out the cursed Matlab.
More common, using a solve function on a rotation matrix can take a few seconds (more than 10, less than 60), but is something I commonly do with the calculator.
The 89 is actually as powerful as most thousand+ dollar math packages. Matlab requires an expensive plugin to do explicit, and it SUCKS at it (okay, entering values sucks, the solver is fine). And so on. It is just plotting that sucks, as.... well, thats a damned small screen
I addressed all of your points above 'via simple dropship' in previous posts along this thread.
SO, jumping into the statement regarding GEO potential energy. 100% correct. You have a lot of potential energy. You also have a huge amount of kinetic energy. In the wrong direction. General rule of thumb for orbits: Speed up, go up. Slow down, go down. Which is why, if you ever found yourself in the same orbit as the ISS, but 2 miles behind it, you would die if you aimed for it and burned your engine -- you would go into a higher orbit and 'slow down' WRT to the station. You actually need to aim AWAY from the station, drop into a lower orbit, which is FASTER (you cover more radians per second along the arc), and then when you are in position, 'speed up' again, to take you up to the ISS.
The only way your gravitation potential energy means anything is when you are 'falling down' a guided path; your rotational motion must be restricted. E.g. you are attached to the elevator cable.
Getting from a 800km orbit to a 40,000 km orbit (~geo) takes exactly as much energy as getting from a 40,000km orbit to an 800km orbit. Matter of fact, I would bet that anybody trying to get home from geosync would actually go into a lunar flyby orbit and re-enter that way; probably cheaper than the change in eccentricty required to make your perigee low enough to slow you into a capture. Because I am bored and don't do this enough:
rp = 6378km + 200km = 6578km
ra = GEO = 42,164 km
a = 1/2(ra + rp) = 24371km
v = root(2*mu*(1/r-1/(2*a)))
mu_earth = G*Me = 3.986E5 km^3/s^2
v with (r = rp) = 10.2km/s
With an apogee of 370km (that of the ISS, IIRC):
rp = 6378km + 200km = 6578km
ra = 6378km + 370km = 6748km
a = 1/2(ra + rp) = 6663km
v = root(2*mu*(1/r-1/(2*a)))
mu_earth = G*Me = 3.986E5 km^3/s^2
v with (r = rp) = 7.882km/s
The Apollo (lunar) reentry speeds were in the range of 11.1 km/s.
So even IF you make no attempt to circularize your orbit first, you STILL only add ~2km/s to your re-entry speed -- about 30%. It makes a difference, but it isn't that big of a deal. And if it is? Circularize your orbit first.
As to finicky, the Space Shuttles heat sheild is a finicky device; heat shields in general are rather well understood. Honestly, how you can even begin to compare a heat shield to an engine (which you implicitly do, in your final paragraph) I cannot begin to fathom.
Size is not a big deal at all, in this case, as there is certainly no WAY we will be getting even close to the size of the space shuttle, which, while not exactly a shining example, is obviously 'doable'. Realistically the logical thing to do would be use a typical tear-drop design, which has most certainly proven itself in practice.
I simply cannot understand why people CARE if it is one way or two way? As far as PEOPLE are concerned (as 'cargo'), using a shuttle to get back will be FASTER. By like a WEEK. As far as materials, once again, tell me ONE thing that you would actually NOT want on a space station? Any raw mass is useful. Once our technology improves, I imagine even human wastes would be put to some use, rather than being shot towards the sun.
Design the 'disposable' climbers correctly, and you can integrate virtually all of the craft into the growing orbital station. Are there some highly-specific actuators that you can't manage to find a use for on orbit? Pack them in a box and send them earthside via a return craft. And your arguement that the heat shield tech is 'finicky' followed by a conclusion that 'you might as well just build rockets'...well, surely you recognize the contradiction.
The problem with our current system is that we Americans insist on doing everything the 'super high tech' way. It isn't elegant, it is failure prone, and it isn't cost effective. 'Cheap' is a relative term. Jet fuel isn't 'cheap' either, but a 747 can burn over 300 thousand pounds of it in one flight. And make a profit.
I argue this because I do not want oth
RE up only:
:~) MAN is it going to suck electrons :~)
My understanding There is no real way to gain back any significant energy without making the system completely impossible to build within the foreseeable future. So we gain no energy by returning.
So, if you gain no energy by returning, you don't want to USE energy (and space, and the mass of the 'passing' systems etc) to return!
So you use super simple cargo craft that are disposable. Remember, if it has valuable components (solar panels, metals) it isn't just going to be pitched out the window! The craft will be in space; those panels will be added to the station, or they will be put to use on some satellite. Nothing is going to be 'thrown away'.
For the more complex craft, if there are any (people movers, maybe?) you store them at the upper station in some collapsed form, and once a month or whatever you send them back planet side via a simple dropship -- just a cargo hold an a heat shield, basically.
Really, my thought on the matter is that humanity cannot yet see a day when we will not need/want to keep every spec of mass that comes up in space, for use on (whatever). We are at LEAST a couple of decades away from digging minerals out of the lunar surface or dragging an asteriod back to mine. Perhaps even a century or more from doing so.
And as for PEOPLE -- current plans don't include them as using the elevator, if I recall (which is sad), but if/when people start using the system, then there would be small, simple return ships every few days. Though getting BACK to earth from Geo would be a real bastard. I suppose one could use pure electric propulsion system though, which would help -- use magnetic drag to slow down. In 20 years we should have the super-conducting materials we would need to make it a reasonable trip, though I'm only daydreaming here.
Oh yeah, and the power thing. I almost wonder if the space elevator would be a major driver of fusion power
Cheers,
Paragraph two is mostly right anyway.
a tellites/geo-high.html
First one is wrong regarding total payload mass. I'd do math to refute the statement, but it has already been done. http://trs.nis.nasa.gov/archive/00000535/
And yeah, the travel time will likely be few days. So what? You can get to LEO in a matter of hours once everything has been built out and systems put in place to deal with any whiplash effects that jumping off before the steady-state altitude.
And it isn't 50K miles to Geo -- it is about 24K miles. I point this out simply because it seems like you are kind of 'creating data' to put it politely. http://liftoff.msfc.nasa.gov/academy/rocket_sci/s
Finally, advantage of capturing energy: again, completely off base with respect to the current design considerations. It would be a LOT cheaper ( I estimate at least by a factor of ten, but that is just a guess) to take high energy fuel up to the anchor mass (at the end of the tethor), than to design the system to actually allow both up and down capabilities.
And even if you HAVE a down capability, that by no means implies that you can capture the potential energy of a decending object. Recall that it is a 'rope', not a bar. And the rope is already in tension. I can see no solution which would allow you to gather any worthwhile amount of energy. You can't run a current through the elevator, as you would then have a stupendeous amount of magnetic drag thanks to Earths magnetic field. So no electromagnetic regen. Which doesn't matter, as *any* form of draggy braking against the cable just looks like more mass to be lifted from the perspective of the anchor mass.
If it were a solid bar than the shift of mass would do the job on its own, thanks to the whole inertia game. If we used a 'dangling rope' and litterally tied the 'Low end' to a mass, lifted it into space and then dropped it back down, you could also get the energy back, minus drag.
In summary, your entire post strikes me as pure opinion, with no basis in fact. If I am mistaken, I urge you to issue some form of defense. While I commend you for caring, I believe that you do a disservice by attacking something you don't understand, while pretending, or worse assuming, that you do.
True in the states/Europe -- but China has never cared about patents much ;~)
different three-body systems
;~)
;~) (*NOT* a Masters degree, just bachelors. Which is like working the McDonalds grill for a year and then trying to get a job as a master chef).
;~) I abused my TI-89 horribly :~)
It is a multi-body problem. Generally solved using a whole bunch of pieces of software, just to check
I've never heard of using multiple 3-body systems. I did this stuff in college not to long ago, so, while I'm not saying it isn't done....
The way we did it (again, as undergrads) was some pretty raw itterative brute force. We did a lot of happy math, don't get me wrong, but the body of the work is done by progs like STK (http://www.stk.com/) from analytical graphics.
It is possible to get a ball park using some happy math tricks. Not enough to really model the trajectory, but enough to say 'oh, I'm going to need a deltaV of 'x' km/s' and you will have a good idea of your error margin (e.g. 'x' +/- 5%). We did these for a number of trajectories as homework problems; a few hours each, pencil paper only. Well, some of use
Kind of my point :~)
;~)
If a company wants a particular item to NOT go through a tunnel when shipping via rail, it can be generally be made to work out. It is a pretty robust network, our railroad system. Could be better, but it isn't bad, considering.
Anyway, the SRBs are 12.2 feet in diameter, whereas the typical rail-car width is somewhere around 10 feet. Tunnels with only 1.5 feet of extra clearance on each side? Somehow I doubt it.
I have no idea what extra packing is done -- might increase the diameter slightly.
Anyway, not something real high on my 'things to care about list'. Just bored and being a pest
Cheers,
the closer to the equator you are, the less energy you need to expend to get into space as you can use the earth's rotational velocity to propel you up there. So you have less fuel or more cargo
You've got part of the story. The real deal is that the minimum energy required to get into an orbit with inclination (x) comes when you launch from the LATITUDE of x, thus taking off due east.
Failing that, launching from some latitude LESS THAN the desired inclination, and launching at the angle (above a line parallel to the equator) which is the same as the desired inclination is generally pretty close to above (5% losses).
So, if you launch from 28 deg. latitude you can get into any orbit with an inclination from 28 to 90 degrees (polar) by simply 'aiming' (aligning the launch vector) along the ground track of you desired orbit (e.g. want a 45 deg. inclination? Launch 45 degrees counter-clockwise from due East). Getting to an inclination of 28 degrees requires that you launch at an angle of... due East.
But if you want to get into an orbit with an inclination of say 20 degrees, and you are launching from Florida.. you can't. I mean that 100%. It is NOT POSSIBLE to get into an orbit lower than your launch latitude WITHOUT an on-orbit maneuver. You MUST get into an orbit (which will generally be the same as your launch latitude, 'cause that is cheapest) and then, once there, 'crank' your orbit down, by firing thrusters. Usually, if one was FORCED to do a plane-change, it would be done in two steps (three, if you count launching as one): first, get into a highly elliptical orbit with a high apogee. Second, fire the plane change burns at apogee. Third (optional but usual) circularize the orbit again.
Grab a marker and an orange, it is easy to see how it all works.
Cheers,
http://www.snopes.com/history/american/gauge.htm
And afternoon thunderstorms pretty much everyday for a good part of the year.
:~) Stepped off a plane in early august and about passed out. And heat is a big deal for gliders.
:~).
;~)
I admit I am highly biased against Houston
And regarding working with an existing space port, there is no way in hell Rutan would do it. I just can't see it happening. Why? Because he doesn't build anything that NEEDS that kind of infrastructure. So a good chunk of his space rent would be paying for things that he wouldn't use.
Anyway, I also admit I've no better ideas. Personally, I'd bet a dollar that they will open a couple of sites. What would rock is if they offered flights between them
Hm. Interesting thought. I'll bet two dollars that within 10 years after starting up tourist flights they will offer direct flights to/from Europe. Could be simple hope, to be honest
Cheers,
I second this question.
Esp. The Oracle part.
Possible addition: which DB systems even made it into serious consideration?
Things like this will help with what is called 'peaking power'. No need to spool up a couple of gas turbines in the middle of the day when you build one of these.
...' etc.
Coal plants are run 24/7 in most cases (base load). Ditto nuke. Mostly this type of tech will remove gas from the mix. I'd bet dollars to donuts that the utilities will be selling or using this power as redundancy rather than 'open market' power. Which is to say, they won't need to hold a contract with another company (or buy another gas turbine) in order to meet their required reliablity rating. Plus they will be able to offer it up as a source of renewable to those who check the little box that says 'I'll pay extra
Just a thought which flowed from the parent post.
Cheers,