The parent to my comment was talking about chemical and biological payloads. A Cessna is just fine for this, if the pilot doesn't care about his own safety.
As for the rest, you're quite right. A couple of years ago a Cessna rammed itself into an office building (in Florida, I think). The photograph of the building with the wrecked plane hanging out of a window made the wires.
I've got well over a hundred hours in C-152s myself (more in other aircraft), so I know what they are and aren't capable of.
Nobody is even doing it at a 1990's level. Or even 1980's.
Shuttle is pretty much 1970's technology, although the SSME (Space Shuttle Main Engine) is about the only part that isn't 1960's technology, at least as far as the launch phase goes. Aerospike SSTO designs were being explored (on paper) in the 1960s, with some limited engine testing in the early 1970s. Some early nuclear engine testing (NERVA, too low thrust for launch) was done in the 1960s, with higher thrust designs (eg DUMBO) being studied.
The only really new technology (ie, that wasn't at least studied on paper in the 1960s or earlier) is laser-launch stuff, which has put masses of a kilogram or two a few hundred or thousand feet in the air. To be useful it would require mind-bogglingly large laser systems and their power supplies.
But there's plenty of life in "old" technologies if coupled with modern materials and different design trade-offs. (Heck, gunpowder has been around for six or seven hundred years, and the basic technology -- with materials and design improvements -- is still the way to make portable weaponry.)
As a scientist I think in SI these days though it took years to unlearn the training of my youth, and I still vascillate between F and C for my preferred temperature unit.
Just compromise and settle on K
Well, we're talking rocket science here. The traditional unit would be R.
It's a force equivalent to that of Earth's gravity (at the surface) exerted on a roughly half-kilogram mass (0.454 kg, to be precise). About four and a half newtons.
The DC-X saw a lot more than two successful flights. At one point in its SDIO (not just Air Force) operated test series, it did two flights with a 24 hour turnaround.
I had the privilege of attending the first public flight, which was the second real flight. Seeing a rocket climb out and then just stop in mid-air is quite something. Then it flew sideways a hundred yards or so and descended tail first to a perfect landing.
Later flights went higher and faster, and one demonstrated its survivability when an at-launch explosion of vented hydrogen blew off part of the aeroshell, and the thing was dropping bits and pieces as it climbed out. The remote pilot (Pete Conrad) just clicked the emergency autoland button and the thing hovered until it had burned off enough fuel to land (the landing gear wasn't designed to support fully fueled weight, it sat on a "milk stool" for launch).
Then NASA took it over and, as you mention, fucked up their first flight. The unconnected leg folded up on landing and the thing fell over, broke apart and burned.
Given the huge workforce that NASA keeps employed to fly the Shuttle (or rather, to act like they're keeping it flying while keeping the actual number of launches to a minimum -- reduces the career risk for NASA managers), it's not surprising that they don't like anything that might threaten that turf. Not that, as you point out, the ridiculous design of X-33 ever remotely threatened it, and gave NASA engineers (and their LockMart, etc, buddies) something else to spend money on.
That's the NASA myth, and why they build crappy spacecraft.
Certainly weight reduction is important, but if you don't keep looking at the overall system, and the trade-offs, you'll fuck up the design. The focus on Isp is a symptom of that. The Shuttle is a prime example of it.
Sure, high Isp means you need less weight of propellant per unit of impulse (thrust * time), which sounds great. So the propulsion guys start focusing on Isp and design exotic high-pressure engines that use fuels like LH2 which is really light and gives you an engine with a 400-range Isp. Never mind that you have to practically rebuild the thing after every flight. (It also gives you a relatively low thrust to weight ratio, so you end up having to augment it at launch with something with high thrust even if crappy Isp, like SRBs)
The propellant guys figure LH2 is cool too -- highest energy per unit weight, and all that.
And the airframe guys just build the lightest structure they can to hold what the propulsion and propulsion guys give them.
All of which leads to a suboptimal design.
LH2 is about the lowest density liquid around. High density urethane foam would sink in the stuff, it's about the same density as lighter weight foams. Which means you need a bloody big tank to put the stuff in. The Shuttle uses 8 times, by weight, as much LOX as LH2, but the LH2 tank is about three times bigger than the LOX tank.
Tankage is heavy. The portion of airframe weight devoted to tankage scales as the volume of the propellant, not the weight.
Replace LH2 with something like liquid methane and your tankage -- and its weight -- becomes much less, which ends up improving your fuel fraction, even with the slightly lower Isp of methane-LOX.
The original Atlas launch vehicle, which used LOX and kerosene and stainless steel tankage, could reach orbit without shedding any stages. (Although it did shed two of its three engines.) It also couldn't carry much payload that way, but we're talking late 1950s technology.
NASA technology is fragile and unreliable because they're more interested in engineering projects for the sake of engineering projects, and then have to hack it back because of budget limitations. Anyone in software development who has seen a project get designed with all sorts of bells and whistles and the designers' favorite new technlogies, only to be turned into some ugly hacks toward the end when deadlines are looming and the budget has run out, will understand this.
Well, that depends on whether one considers an "assload" to be a measure of weight (mass) or of volume.
If one takes "ass" as synonymous with "donkey", then the measure is probably by weight, and a metric assload is probably in kilograms. Multiply by 2.2 to get pounds.
If one takes the other common meaning of "ass" then it may well be a unit of volume, but the specific metric unit could be anything from milliliters or perhaps centiliters for average, or perhaps litres for the goatse.cx guy.
And on that note I think I've gone about as far with this comment as I care to...
Shareholders are the last to be taken into account. They're owners of the company. The only thing that prevents the extra money that SCOG might owe somebody from coming out of their pockets is that that's the nature of a limited company -- a shareholder's potential loss is limited to how much they invested in the stock -- but they could lose all of that with no recourse (well, other than suing McBride etc.).
The court could sequester the assets without necessarily awarding it all to Novell. If SCOG declared bankruptcy before the case was decided and any settlement awarded, then the court could choose to make it part of the assets to be divvied up amongst all creditors, with Novell just happening to be the biggest creditor.
Or, it could decide that the money was never SCOG's to start with so Novell gets it all, and if it isn't enough to settle the Novell claim, then Novell joins the pool of creditors for whatever amount is still owed.
If SCOG declares bankruptcy, in the unlikely event that there's anything left after all the assets down to the office furniture are sold off and all judgements and creditors paid off, then the shareholders split what's left. But I imagine that will be a negative number.
I'm going by what the sign on the restaurant said. It was definitely "Gut", with an upside-down "L", which I thought was funny as hell. Somewhere I have a photo of it.
Maybe some manager has since realized the joke and changed it.
Well, the Cyrillic letter for the sound 'H' may well be 'X' (although I thought that was more of a soft fricative 'ch'), but the Pizza Hut (a few blocks from the McDonalds if I remember right, near the Baskin-Robbins) used the Cyrillic for 'G' (like a Greek gamma) in its name. Maybe whoever did the translation had a sense of humor.
Unwanted email steals my time, even if it's just the time to delete it. Stealing my time is taking part of my life. We're not just talking about one email here, we're talking about a major spammer.
Last (okay, only) time I was in the Soviet Union (not long before the end), there was at least McDonalds, Baskin-Robbins, and Pizza Gut (there's no letter 'H' in Cyrillic).
Well, besides the fact that they dont geographically overlap at all.
Historically they do. I don't recall if there were ever tigers in Africa but there were certainly lions in Asia (and indeed in Europe). However, they prefer different habitats (forest vs grassland), and have different hunting patterns. Which came first (habitat preference or hunting method) is an interesting (and probably unresolvable) question.
The point isn't that tigers and lions would interbreed in the wild, the point is that tigers and lions are so genetically similar that their branch point from a common ancestor isn't that long ago, and the branching (and speciation) occurred because of the different habitat preferences and because tiger ancestors preferred to mate with tiger ancestors rather than lion ancestors.
(The fact that tigers and lions can mate and produce not only viable but occasionally fertile offspring throws a wrench into the usual definition of "species". Many of the anti-evolutionist arguments boil down to semantics rather than biology, so it's worth noting where these definitions break down.)
Two organisms have to have the mutation present at the same time.
No, that only matters if the trait is recessive. A dominant trait only requires one copy of the gene to manifest itself. If the owner of the mutated gene (dominant or recessive) survives to reproduce, on average half the offspring will have it. If the gene is harmless or slightly beneficial, it will eventually spread through the population.
Indeed, some mutations can be beneficial if only inherited from one parent but potentially harmful if inherited from both. The gene for sickle cell anemia is a classic example of this -- singly, it confers some resistance to malaria without causing blood cells to sickle.
(The whole "chicken and egg" question is ridiculous. Anyone can observe a chicken hatch from a (chicken) egg and grow to maturity. And a simple genetic analysis will show that a (fertilized) egg is genetically different from the chicken that layed it. Go back up the tree far enough and you get something not-chicken laying a chicken egg. The thing is, there's a lot of variables there, and the definitions are necessarily fuzzy -- "chicken" defines a range, not a point.)
Well, if you really want to monkey wrench it, don't delete your cookies file but go in with an editor and change some of the strings. Thow in some really long ones or some odd characters if you want to try breaking the parser.
Odds are the tracking system will probably just reject it as garbage rather than actually break or link your info to somebody else, but you never know.
If you only delete cookies at shutdown, then for as long as you have your browser open (sometimes days, for me) ad sites can track you from one site to another (assuming they have ads). If you really don't want to be tracked, you need to block the cookie and/or ad host.
(And be aware that if the ad server and content server sites agree, the ad site can correlate that with any personal info you've provided to the content site by way of an ID in the ad URL. Subject to the content site's privacy policy, yadda, yadda, yadda.)
Slashdot Mirror
Coming into effect in 2007 ... but in under a year?
Is it 2006 where you are? Can you send me some stock quotes?
Extrasolar moons of HD 28185 b and iota Hor b, if they exist, would have the additional advantage of getting enough solar radiation
Yet another shining example of NASA attention to detail.
The parent to my comment was talking about chemical and biological payloads. A Cessna is just fine for this, if the pilot doesn't care about his own safety.
As for the rest, you're quite right. A couple of years ago a Cessna rammed itself into an office building (in Florida, I think). The photograph of the building with the wrecked plane hanging out of a window made the wires.
I've got well over a hundred hours in C-152s myself (more in other aircraft), so I know what they are and aren't capable of.
Any group with Al Qaeda's assets would find it far easier to just buy military gear ready-made than do the necessary R & D for a homebuilt job.
Or just strap it into the passenger seat of a Cessna, it's not like those fanatics are concerned about personal safety.
(I know most of the posts in the parent's vein are tongue in cheek, but there are always folks who don't get the joke.)
Is ANYONE doing rocketry at a 2000's level today?
Nobody is even doing it at a 1990's level. Or even 1980's.
Shuttle is pretty much 1970's technology, although the SSME (Space Shuttle Main Engine) is about the only part that isn't 1960's technology, at least as far as the launch phase goes. Aerospike SSTO designs were being explored (on paper) in the 1960s, with some limited engine testing in the early 1970s. Some early nuclear engine testing (NERVA, too low thrust for launch) was done in the 1960s, with higher thrust designs (eg DUMBO) being studied.
The only really new technology (ie, that wasn't at least studied on paper in the 1960s or earlier) is laser-launch stuff, which has put masses of a kilogram or two a few hundred or thousand feet in the air. To be useful it would require mind-bogglingly large laser systems and their power supplies.
But there's plenty of life in "old" technologies if coupled with modern materials and different design trade-offs. (Heck, gunpowder has been around for six or seven hundred years, and the basic technology -- with materials and design improvements -- is still the way to make portable weaponry.)
As a scientist I think in SI these days though it took years to unlearn the training of my youth, and I still vascillate between F and C for my preferred temperature unit.
Just compromise and settle on K
Well, we're talking rocket science here. The traditional unit would be R.
For anyone having trouble getting used to metric, think of one newton as the amount of force required to lift an apple off the ground.
Or a Quarter-Pounder* to your mouth.
(* pre-cooked weight)
It's a force equivalent to that of Earth's gravity (at the surface) exerted on a roughly half-kilogram mass (0.454 kg, to be precise). About four and a half newtons.
(lbf = pounds force, not pounds feet)
The DC-X saw a lot more than two successful flights. At one point in its SDIO (not just Air Force) operated test series, it did two flights with a 24 hour turnaround.
I had the privilege of attending the first public flight, which was the second real flight. Seeing a rocket climb out and then just stop in mid-air is quite something. Then it flew sideways a hundred yards or so and descended tail first to a perfect landing.
Later flights went higher and faster, and one demonstrated its survivability when an at-launch explosion of vented hydrogen blew off part of the aeroshell, and the thing was dropping bits and pieces as it climbed out. The remote pilot (Pete Conrad) just clicked the emergency autoland button and the thing hovered until it had burned off enough fuel to land (the landing gear wasn't designed to support fully fueled weight, it sat on a "milk stool" for launch).
Then NASA took it over and, as you mention, fucked up their first flight. The unconnected leg folded up on landing and the thing fell over, broke apart and burned.
Given the huge workforce that NASA keeps employed to fly the Shuttle (or rather, to act like they're keeping it flying while keeping the actual number of launches to a minimum -- reduces the career risk for NASA managers), it's not surprising that they don't like anything that might threaten that turf. Not that, as you point out, the ridiculous design of X-33 ever remotely threatened it, and gave NASA engineers (and their LockMart, etc, buddies) something else to spend money on.
So space flight is all about weight reduction.
That's the NASA myth, and why they build crappy spacecraft.
Certainly weight reduction is important, but if you don't keep looking at the overall system, and the trade-offs, you'll fuck up the design. The focus on Isp is a symptom of that. The Shuttle is a prime example of it.
Sure, high Isp means you need less weight of propellant per unit of impulse (thrust * time), which sounds great. So the propulsion guys start focusing on Isp and design exotic high-pressure engines that use fuels like LH2 which is really light and gives you an engine with a 400-range Isp. Never mind that you have to practically rebuild the thing after every flight. (It also gives you a relatively low thrust to weight ratio, so you end up having to augment it at launch with something with high thrust even if crappy Isp, like SRBs)
The propellant guys figure LH2 is cool too -- highest energy per unit weight, and all that.
And the airframe guys just build the lightest structure they can to hold what the propulsion and propulsion guys give them.
All of which leads to a suboptimal design.
LH2 is about the lowest density liquid around. High density urethane foam would sink in the stuff, it's about the same density as lighter weight foams. Which means you need a bloody big tank to put the stuff in. The Shuttle uses 8 times, by weight, as much LOX as LH2, but the LH2 tank is about three times bigger than the LOX tank.
Tankage is heavy. The portion of airframe weight devoted to tankage scales as the volume of the propellant, not the weight.
Replace LH2 with something like liquid methane and your tankage -- and its weight -- becomes much less, which ends up improving your fuel fraction, even with the slightly lower Isp of methane-LOX.
The original Atlas launch vehicle, which used LOX and kerosene and stainless steel tankage, could reach orbit without shedding any stages. (Although it did shed two of its three engines.) It also couldn't carry much payload that way, but we're talking late 1950s technology.
NASA technology is fragile and unreliable because they're more interested in engineering projects for the sake of engineering projects, and then have to hack it back because of budget limitations. Anyone in software development who has seen a project get designed with all sorts of bells and whistles and the designers' favorite new technlogies, only to be turned into some ugly hacks toward the end when deadlines are looming and the budget has run out, will understand this.
Well, I, for one, welcome our 10th planet overlords.
(Hey, somebody was going to say it!)
Well, that depends on whether one considers an "assload" to be a measure of weight (mass) or of volume.
If one takes "ass" as synonymous with "donkey", then the measure is probably by weight, and a metric assload is probably in kilograms. Multiply by 2.2 to get pounds.
If one takes the other common meaning of "ass" then it may well be a unit of volume, but the specific metric unit could be anything from milliliters or perhaps centiliters for average, or perhaps litres for the goatse.cx guy.
And on that note I think I've gone about as far with this comment as I care to...
Shareholders are the last to be taken into account. They're owners of the company. The only thing that prevents the extra money that SCOG might owe somebody from coming out of their pockets is that that's the nature of a limited company -- a shareholder's potential loss is limited to how much they invested in the stock -- but they could lose all of that with no recourse (well, other than suing McBride etc.).
The court could sequester the assets without necessarily awarding it all to Novell. If SCOG declared bankruptcy before the case was decided and any settlement awarded, then the court could choose to make it part of the assets to be divvied up amongst all creditors, with Novell just happening to be the biggest creditor.
Or, it could decide that the money was never SCOG's to start with so Novell gets it all, and if it isn't enough to settle the Novell claim, then Novell joins the pool of creditors for whatever amount is still owed.
If SCOG declares bankruptcy, in the unlikely event that there's anything left after all the assets down to the office furniture are sold off and all judgements and creditors paid off, then the shareholders split what's left. But I imagine that will be a negative number.
American PC parts,
That's got to be an oxymoron. What PC parts are made in America these past few years?
I'm going by what the sign on the restaurant said. It was definitely "Gut", with an upside-down "L", which I thought was funny as hell. Somewhere I have a photo of it.
Maybe some manager has since realized the joke and changed it.
I think it was modded funny for the "Pizza Gut" reference. I thought that was pretty funny myself at the time.
There sure wasn't a Subway in Saint Petersburg when I was there -- indeed it was still Leningrad; they voted on the name change a few days later.
Well, the Cyrillic letter for the sound 'H' may well be 'X' (although I thought that was more of a soft fricative 'ch'), but the Pizza Hut (a few blocks from the McDonalds if I remember right, near the Baskin-Robbins) used the Cyrillic for 'G' (like a Greek gamma) in its name. Maybe whoever did the translation had a sense of humor.
Unwanted email steals my time, even if it's just the time to delete it. Stealing my time is taking part of my life. We're not just talking about one email here, we're talking about a major spammer.
Sounds like self defense to me.
Last (okay, only) time I was in the Soviet Union (not long before the end), there was at least McDonalds, Baskin-Robbins, and Pizza Gut (there's no letter 'H' in Cyrillic).
Well, besides the fact that they dont geographically overlap at all.
Historically they do. I don't recall if there were ever tigers in Africa but there were certainly lions in Asia (and indeed in Europe). However, they prefer different habitats (forest vs grassland), and have different hunting patterns. Which came first (habitat preference or hunting method) is an interesting (and probably unresolvable) question.
The point isn't that tigers and lions would interbreed in the wild, the point is that tigers and lions are so genetically similar that their branch point from a common ancestor isn't that long ago, and the branching (and speciation) occurred because of the different habitat preferences and because tiger ancestors preferred to mate with tiger ancestors rather than lion ancestors.
(The fact that tigers and lions can mate and produce not only viable but occasionally fertile offspring throws a wrench into the usual definition of "species". Many of the anti-evolutionist arguments boil down to semantics rather than biology, so it's worth noting where these definitions break down.)
Two organisms have to have the mutation present at the same time.
No, that only matters if the trait is recessive. A dominant trait only requires one copy of the gene to manifest itself. If the owner of the mutated gene (dominant or recessive) survives to reproduce, on average half the offspring will have it. If the gene is harmless or slightly beneficial, it will eventually spread through the population.
Indeed, some mutations can be beneficial if only inherited from one parent but potentially harmful if inherited from both. The gene for sickle cell anemia is a classic example of this -- singly, it confers some resistance to malaria without causing blood cells to sickle.
Which came first? [Butterflies or caterpillars?]
Well, the egg, actually.
(The whole "chicken and egg" question is ridiculous. Anyone can observe a chicken hatch from a (chicken) egg and grow to maturity. And a simple genetic analysis will show that a (fertilized) egg is genetically different from the chicken that layed it. Go back up the tree far enough and you get something not-chicken laying a chicken egg. The thing is, there's a lot of variables there, and the definitions are necessarily fuzzy -- "chicken" defines a range, not a point.)
Well, at least until Marketing gets into the act...
And maybe the beginning of that should be rewritten as "a good engineer".
Well, if you really want to monkey wrench it, don't delete your cookies file but go in with an editor and change some of the strings. Thow in some really long ones or some odd characters if you want to try breaking the parser.
Odds are the tracking system will probably just reject it as garbage rather than actually break or link your info to somebody else, but you never know.
What isn't there to like?
Well, the fact that it doesn't work, for one.
If you only delete cookies at shutdown, then for as long as you have your browser open (sometimes days, for me) ad sites can track you from one site to another (assuming they have ads). If you really don't want to be tracked, you need to block the cookie and/or ad host.
(And be aware that if the ad server and content server sites agree, the ad site can correlate that with any personal info you've provided to the content site by way of an ID in the ad URL. Subject to the content site's privacy policy, yadda, yadda, yadda.)