which are the main variables your local forecaster uses to try and predict weather trends
Um, yeah...I'm pretty sure your local forecaster just looks at the temperature, pressure, and humidity maps provided by NOAA and says, "gee, that's high pressure and it's warm and wet. There's low pressure over here so I think that's going to move onshore and it'll be 54 and cloudy with a 62.7% chance of rain." Or depending where you actually get your weather, he just goes to NOAA.gov, types in the zip code, then spends the rest of the day preparing his fancy animations of the jet stream for the 7 o'clock news.
Anyway, I seriously doubt the scientists involved in this project have any delusions about telling us when good days are for a picnic in upstate New York in July of 2036. Right now we're at the point of predicting El Nino's and La Nina's based on looking at the long term patterns and comparing those to the ocean temperatures. Compared to the fantastic summary, this project is no doubt more along the lines of those predictions, but carried out further and perhaps made a little more specific. Instead of planning for El Nino weather to be slightly warmer and wetter in continental climate areas (if I remember right) this summer, they might tell us to expect average highs in the American midwest to be 1-2 degrees higher with 10% more rainfall than the average during July of 2010.
Personally, I'm more interested in extending the current 1 week forecasts out to a month or more and increasing the accuracy of short term forecasts. I think it's possible to make reasonable approximations of most of the effects you list. Then again, with articles like this, who knows what they're really up to.
The nitrogen is used to pressurize the hydrazine tanks to feed the reaction control system. It's pretty simple. Rather than have pumps that would be corroded by the hydrazine, they just warm up the nitrogen a little bit and the pressure increases. They know the pressure is dropping, but they're not sure if it's because they're losing nitrogen or losing hydrazine. I suppose they decided it wasn't worth the extra effort, cost, complexity, and weight to be able to isolate the tanks soley for the purpose of determining where a leak was, should one occur, so they just assume the worst case and prepare for that, if necessary.
Hydrazine wasn't chosen for performance. It actually has a rather low ISP. It was chosen for reliability. The reaction control jets have to fire repeatably far more times than other types, and usually while cold. In this case, NASA uses a hypergolic form; one which spontaneously combusts in the precense of another chemical. The two are released simultaneously into the reaction control jet and voila, fire.
NASA would love to develop a methane based version with a much higher ISP and less handling risk, but it got cut out of their CEV budget. I think now they're sponsoring a private company to develop one via the COTS program. It would have to be actively ignited, which raises reliability concerns. I'm not sure what other design problems are holding it up.
Hydrazine reacts in the precense of a catalyst such as silver or iridium, which is why combustion chambers of many reaction control rockets are lined with such. Hydrazine is semi-stable. It will breakdown in the precense of the catalyst or if it warms up to the proper point. If neither happens, you're fine. The engineers who actually know how the system is designed (ie, not you), and know where stuff can get into, where it might come into contact with a catalyst, or where it might warm up are the ones qualified to analyze the risk.
As for the risk of explosion, well that's poorly written, but if you don't have enough to cause a pressure increase of damaging magnitude, well then there's nothing to worry about. In this case they have a lot less. That suggests to me they looked it over and decided it must be leaking in a way that there's no place for it to accumulate.
Furthermore, according to NASA, they don't actually use pure hydrazine in the shuttle RCS jets. They use nitrogen tetraxide and monomethyl hydrazine (add on a carbon atom), which are hypergolics. They're more stable but they react spontaneously in each others presence.
Of course, the shuttle engineers don't have a clue about any of this. They like playing dice with their co-workers lives.
Hmm...the military has been working on this for years to destroy tactical missiles and artillery rounds in flight. I'd be very surprised if it shows up at airports before it shows up in air defense artillery units.
(The links I provided describe intermediate systems. One is a developmental laser. The other is not capable of engaging aerial targets).
It seems this point has to be made 3 or 4 times every time a submission about Bigelow comes up...and people still don't believe it. Zodiak boats are a perfect example of a robust inflatable structure. Another good example is a tire. Compare the impact resistance of those things to a thin sheet of aluminum!
The inflatable module is really only different in that uses air pressure to maintain its shape instead of framework (actually, there is a framed core down the middle with avionics and inflation equipment and to support mounting equipment inside the pressurized portion...also similar to Zodiaks). The skin is several layers of different insulating, containing, and protective materials. Some of these are tougher than Kevlar! The result is a module that is (hopefully) stronger by weight than equivalent rigid capsules, has more interior volume, and fits in a smaller launch fairing.
Along with the confusion about the vulnerability being similar to a balloon, people also get confused about the volume. Unlike a balloon, it doesn't grow to several dozen times its packed volume. I think it's closer to a factor of 2 or 3, depending on the model. It won't revolutionize living in space, but if it lives up to its potential, it will be another step in the right direction.
FYI, NASA originally started development work on the technology under the Spacehab project to be used for one or two modules on the ISS. Due to budget constraints and time limits, they chose the traditional modules and set the development effort aside until Bigelow bought rights to the technology. The technology might also see applications in long-term lunar or Martian bases.
The satellites the "article" talks about are the result of MIT and DARPA's Synchronized Position Hold Engage and Reorient Experimental Satellites (SPHERES...sounds like they were stretching a little bit to get decent sounding acronym). The immediate focus of research is to develop control systems for automated docking, with later potential applications of station-keeping and maybe even satellite repair. For example, you may recall a DoD satellite repair mission that failed last year when the robot failed to latch on to the target satellite and accidentally bumped into it before running out of fuel.
The SPHERES are tested inside the ISS and manuever using cold gas thrusters (standard CO2 bottles, I think). The goal is for them to maintain alignment with a hand held beacon that the astronauts move about inside the station. For this generation, I believe the beacon is auditory based. Obviously that won't work outdoors, but this is a pretty low-cost, basic level development effort.
You're wrong on pretty much the entire post. There are quite a few different types of radiation shields, or more relevantly, radiological protection.
The simplest is something that blocks radiation (the electromagnetic kind, not the imaginary magical glowing stuff you see in scifi channel specials or referred to by greenpeace activists with a degree in philosophy). Sunglasses are an example I hope most people are familiar with. They block a limited range of wavelengths, typically in the UV, to protect the eyes. In reactors, gamma rays (high energy radiation) are typically blocked by heavy atoms (lead) or thick layers of concrete and steel, or a combination. 2 feet of concrete reduces gamma radiation flux to 0.1% of incoming intensity.
Then there is protection against beta particles (high energy electrons) and alpha particles (radioactive helium isotopes). These are far easier to contain than gamma rays due to their mass, and lightweight materials like a thin layer of aluminum or many plastics are sufficient. Gamma radiation is often produced from "braking" of high speed electrons or decay of helium isotopes, but we already dealt with that above. Beta particles and alpha particles are not technically radiation, but they are radiological threats.
Neutron bombardment is probably what you were thinking of. Neutrons are released during fission and absorbed by other atoms, making the nuclei unstable and causing further breakdown, perpetuating the chain reaction. Neutrons are also, however, absorbed by surrounding material such as the steel casing and control rods, doping those materials to form radioactive isotopes. As a result, these parts, all of which are inside the reactor vessel as opposed to all over the entire plant like you claim, become low-level radioactive waste when the vessel is decommissioned. Decommissioning has to be done, not because the whole thing becomes so radioactive it's dangerous to operate, but because neutron bombardment causes the metals to become brittle and less structurally sound.
Re-reading your post, I think you're confusing what you've read about the aftermath of the Chernobyl accident with typical plant operations. Chernobyl is completely different because the radioactive particles (a little bit of alpha particles, mostly radioactive fuel, reaction products, and neutron bombarded reactor materials) escaped the containment structure due to the explosion. Once scattered around the countryside by the explosion and weather, their proximity (especially when ingested) is what caused problems like thyroid cancer and, immediately after the accident, radiation sickness. The one hour rule was workers in the zone when they were building the "sarcophogaus" over the remains of the reactor. You've probably heard the claim that a person living a mile downwind from a nuclear power plant receives less radiation than if they watched an extra hour of TV per day. The ground is fine. Certainly not radioactive. The Trojan plant 40 miles from my house is currently being decommissioned. 15 years from now, when that's done and the last of the low-level waste is removed from temporary storage and taken to a long-term repository, the site will be a park.
The one problem left, that you actually almost did get right because it's a cost that wasn't initially appreciated (currently there is a tax on nuclear-generated energy to cover it), is the waste fuel, by-products, and reactor that have to be disposed of. The material is sorted by radioactivity and type and disposed of in various ways. This is pretty complicated, so I'll just describe the nastiest threat, which is the spent fuel. It's chemically processed into a solid, chemically stable ceramic that is not water-soluable. This is then encased in steel and further encased in reinforced concrete and will eventually be buried 1000 feet underground in a federal repository. Degredation of the containers in the next 10,000 years is unlikely, after which the most radioactive stuff will have decayed. Contamination by natural mea
Of course, the *AA's have circumvented the roughly equivalent precendence in the car analogy by arguing that the user does not buy content. Instead they maintain that you buy or lease a license (or something to that effect) to access the content. Ownership of the content remains in the hands of the creator. This much doesn't seem overly outrageous to me. My problem is when they tell me how I will access the content. I can't think of any good car analogy for this.
Arguring for this limitation is motivated by the fact that it is possible and even easy to violate the terms of the claimed license by making copies and giving them to your friends, etc. There doesn't seem to be too much disagreement that this sort of behavior should be illegal. However, the lawyers are attempting to shift the problem from being about people who do perform an illegal act to people who can perform an illegal act. A car analogy would be: because I can use a leatherman to hot wire a car, I should not be allowed to own a leatherman. Actually, in retrospect, we're talking about intellectual property rather than physical property. Perhaps I should say that because I can use a digital camera to steal design details from Ford, I shouldn't be allowed to own a digital camera. For that matter, perhaps I shouldn't be allowed to own eyes. And since I can use my ears and voicebox to capture and replicate (in even more painful fashion that Britney Spears, I admit) "Oops I did it Again," maybe I shouldn't be allowed to have those.
I believe this kind of restriction is called pre-emption. In some cases it is considered legitimate. For example, we don't let people have unlicensed explosives, not because they will blow something up, but because if they do, the damage will probably be significant and potentially irrepairable. On the other hand, if I steal a movie (actually, watch an unlicensed movie), I've deprived the content owner of $15 and nobody died. Regulating piracy my way (prosecuting the guilty) might not engender as much obedience of the relevant laws and therefore some amount of increase in losses due to piracy. Regulating that the MPAA/RIAA way (crippling the innocent) could mean a very significant loss of freedom for users to not only play licensed to content, but also to develop and distribute new content. It also has a cost in terms of required features to support DRM and other similar encumberments. Given the balance of these factors, pre-emption seems to me like a terrible policy for controlling piracy.
I'd like for religious people to point out one single thing that religion is needed for, I haven't found one single thing.
Well, if it turns out that some particular group of us is right and you will someday meet your maker... (I'll leave off at an ellipse rather than risk sparking a discussion over who might actually be right).
I'm a little perplexed by the intermingling of the terms "piracy" and "other side of the coin."
The use of the term piracy suggests (although I won't say it's definitive) that something illegal is being done. Talking about the other side of the coin would then seem to be making a claim it's ok to do bad if something good comes out of it, which I suppose is worth considering if the "net good," for lack of a better term, of piracy exceeds that of legal use. However, I'm letting myself digress. If people want to argue their case as a form of fair use, then calling their own actions piracy does not help others to see it as something other than stealing. When I hear people talking about the other side of the piracy coin, I think of a parallel along the lines of how the predation of US merchant ships by the Barbary pirates must've been good for the economy of Tripoli, and therefore should be allowed.
Digressing again, I was disappointed by Techdirt's contention that "piracy" was ok because it changes the business model by making recorded music a promotion for concerts and other more tangible products. My problem here is that they're attempting to dictate the business model that the entertainment industry should adopt, rather than allowing them to stick to their "increasingly obsolete" (techdirt's term) business model and running themselves into the ground while more progressive companies take advantage of the changes (assuming the new business model actually is superior (and how is that superiority quantified, anyway?)). Besides, concerts cost too much as it is.
I don't know how old you're client was, but I have a pet theory that the reason our grandparents can't handle VCR's or computers is because they're used to farm machinery and exposed gears, where if you screw up because you don't really know what you're doing, somebody gets maimed or killed. They don't like messing with things they don't fully understand.
With computers, screwing around with something that you don't get just means losing a little bit of data or picking up a virus.
Rinkworks has a great collection of stories. I question the veracity of some of them, but they're still funny. When I first discovered it, I had to stop after a couple pages because I was losing my faith in mankind's ability to not be completely hopeless.
The Register's list has a couple good ones (The hungry floppy drive is my favorite), but some of them seem rather lame given the number of stories out there, and they're written like they were copied and pasted from a chatroom. Example: "Someone telling me their 'broadbean' connection is down." I would even say that my 9 year old can write better than that, except I don't have a 9 year old son.
Also, I'm sorry because I know how important this topic is to Slashdot, but "Girl from HR with large chest walks in to department..." (more spectacular writing) doesn't exactly strike me as a bewildering IT anecdote. It's more like someone got excited about directly interacting with the HR girl and felt a need to share their excitement with the Register.
Along the exact same lines: "Damn the torpedoes! Full speed ahead."
Farragaut didn't have time to prance about in the minefield at Mobile Bay while being shot at by confederate ships and shore batteries. In fact, I don't think any of the ships hit mines except for the USS Tecumseh, which discovered them in the first place.
Soyuz has an ablative heat shield. It's probably made of some sort of ceramic, formed into 8 layers called "blankets" (I think they're only flexible enough to allow for expansion and contraction of the spacecraft, not like a quilt). The capsule is single use, so the heat shield only needs to survive one re-entry, and the exposed surface area is small, reducing overall weight. The ablation (burning away of small particles) carries heat away from the capsule. A similar system has been used on pretty much every entry system except for the shuttles, even the Mars rovers. The Russians did use a system nearly identical to the space shuttles for their Buran shuttle, which was abandoned after one flight due to budget problems.
The weight and maintenance of an ablative heat shield were prohibitive in a very large reusable system like the shuttle. Instead, the leading wing edges and nose of the shuttle are protected by reinforced carbon-carbon tiles, the underside by ceramic tiles that are in some ways similar to aerogel, and other sensitive areas by a heat resistant cloth. The carbon-carbon is the most effective and actually pretty strong, but about 6 times more dense than the other options. Read more.
In short, no the Russians haven't had fatal problems with their thermal protection, but it's not feasible for a vehicle like the shuttle.
Sorry to piggyback on a joke. This is the actual status, copied from NASA's shuttle page
Status Update
During a routine inspection overnight after the draining of the external fuel tank, a crack was discovered in the foam near a bracket that holds the liquid oxygen feedline in place. This piece of foam has been estimated to be 0.0057 pounds. It is believed that the rain experienced during yesterday's launch attempt caused water to run down the feedline and form ice near the top of the strut next to the feedline bracket. As the tank warmed and expanded, the ice that formed most likely pinched the foam on the top of the strut, causing a crack and eventual loss of the small piece of foam.
At a Mission Management Team meeting this morning, a decision was made to continue analyzing available data before making a final decision regarding tomorrow's launch attempt. The question is whether there needs to be a hands-on inspection of the area around the foam crack before launch.
The Mission Management Team will meet again at 6:30 p.m. EDT to hear the results of the analysis and make a decision on whether we will attempt to launch tomorrow or Wednesday. Currently, there is a 60 percent of favorable launch weather for tomorrow and a 40 percent chance of favorable weather for Wednesday.
It sounds like "crack" isn't a very descriptive term. A small piece broke off, probably due to the weather-related causes. They're trying to decide if they need to erect a platform to do a hands-on inspection.
On the source page there's a picture that took me a minute to figure out, so I'll explain it. The solid orange to the left is the main body of the external tank. The round orange vertical item in the center of the picture is the LOX feed line. The big metal piece is probably part of the tripod mount. Just below and to the right of the mount is one of the brackets that holds the LOX line in place, covered in foam. Looking closely, you can see a little triangle of white where the little chunk (about 4 long) of foam spalled off. I assume the T-shaped feature to the right of that is the so-called ice/frost ramp, which they're concerned may be at risk for falling off in flight. It's much clearer in the high res picture linked on that page.
At first glance, it doesn't look like a concern at all, but obviously NASA wants to make sure of that. If anybody has serious reservations, they'll setup a platform to get somebody who knows what to look for up close to it and look for evidence that this may increase chances that the ice/frost ramp or other pieces of foam may fall (smaller cracks, loosening of the frost ramp, etc).
For comparison, this piece of foam is estimated at 0.0057 pounds and may be as large as a cellphone. The piece that struck Columbia's wing weighed an estimated 1.67 pounds and was described as "briefcase-sized"
(Also, the joke is 2nd Tuesday of next week. Your rendition makes about as much sense as a screen door on a battleship):p
To the best of my knowledge, that is not true. Look at the crew roster. All but one (a doctor in biometeorology for ESA) have engineering degrees, and almost all of them have masters or doctorates.
Also, they effectively do have a say. Nobody is holding a gun to their head. If they truly felt the risk was unacceptable (keeping in mind, however, these guys happily take risks most people find unacceptable), they could refuse to go.
Furthermore, and the astronauts no doubt realize this, despite their educational background and technical understanding, they are seldom in the best position to make the final call. They know the STS pretty well and provide input on some of the major decisions, but really the guys who should make the final calls are the administrators based on the recommendations of the engineers who know most about the relevant issues. In this case, they are seeking recommendations from the engineers who know most about the foam. In the end, the astronauts have to trust to some degree that these guys know what they're doing, so if they don't trust them or they feel sufficient reservation (enough to overcome their own drive to succeed) about the administrators decisions, they simply won't suit up.
The shuttle's got something like 10 million parts. If Joe Engineer tells Frank Skywalker that doohickey 3178219 is 1.6 mm out of tolerance and it'll take a week to make a new one, Frank isn't going to be say "Oh no, things should be in tolerance. I'm not getting on that thing." He's going to ask the engineer what ramifications this might have for the mission and if he should be concerned, to which Joe might reply, "Well, it might make the toilet seat squeak when you try to put it down. No worries." Given the complexity of making a go/no-go call in the foam case, it drives me up the wall to see some of the other comments from slashdotters not involved with NASA and often probably not with a mechanical engineering education criticising NASA for even considering launching when there's a small crack in the foam and we don't even know yet if it will affect the shedding or not.
Actually, the discussion right now is whether or not a 4-5 inch crack actually is something to sneeze at. Cracking in the foam is not a new occurance. No doubt there's a bunch of engineers running CFD analysis like mad right now trying to figure out how much extra stress the crack exposes the foam to and whether this actually does increase the likelihood of shedding or not. If the crack is on a sheltered face, it might have no effect. It is even remotely possible that the crack formed in the process of relieving some residual stress and in that case possible that it's a little better off now, although it's doubtful the analysis would be able to determine that. Furthermore, attempts to fix it may actually make the problem worse by stressing the crack with new material. As you can see, it's not an easy question to address.
Also, there's several problems with foam inside the tank. Number 1 is manufacturing and inspection difficulty. The tank has to be sealed off after the foam is applied, which could affect the foam and we'd have no way of knowing. If for any reason the integrity was severely effected, you could still get ice on the outside of the tank. Number 2 is weight. Putting the foam inside the tank enlarges the structural volume accordingly, making the tank heavier. Number 3 is isolation. I mean protecting the foam from the fuel, which also means more weight. If the fuel is directly exposed to the foam, it can soak in, first of all making it effectively unavailable to burn, and secondly significanly reducing the insulating value of the foam (think about how cold a wet sweatshirt is on a cold day). Also, you really would not want a piece to fall off and get sucked into the turbopumps or for the foam to react with the fuel. Number 4 is the miscellaneous hardware. None of the foam that is a concern would be suitable to place inside, although it turns out that it may be acceptable to remove the highest risk portions. The tripod ramp and the proturbance air load ramp foam have been removed. This crack formed on an ice frost ramp on the brackets that hold the pipes in place, but NASA's not yet comfortable with the aerodynamic changes that would result from removing that, and foam falling from that region either has not been observed to strike the orbiter or has been really small pieces if it has. The ice frost ramps may still be removed for the next flight.
I don't fear for the space program if Discovery were to be lost. It would hurt it for sure, the shuttle may be immediately retired, and I doubt the ISS would ever be finished, but NASA and even manned spaceflight would still continue. Theoretically though, the chance of a problem on this flight is lower than possibly any previous flight. Every major concern has been addressed to some degree, as have many of the minor ones. There's backup plans ready and an unprecendented level of procedure in place to identify any problems if they do occur. There is still risk, but I argue less than on the 114 previous flights.
Honestly, senior managers don't have time to review every minor detail of every project. This kind of structure works as long as people at the lower levels are competent to know what information is relevant to pass along, how much information their superiors can handle at once, and what makes a critical bullet point. If you watch the interviews and press conferences, you'll notice Griffin and the other top NASA officials have a pretty good handle on what's going on. It certainly doesn't hurt that Griffin is an experienced engineer himself and understands the technical side of the operation better than his predecessor.
Also, what are the "many problems" you refer to? I'm not saying there's no problems, but I've seen a lot of things fixed in the last 3 years, so I'm not sure if there's anything specific you're referring to, or if you just thought you'd join in the NASA-bashing. It's not like we know about the foam crack, but through some marvel of a broken communications structure at NASA, the top people are utterly unaware of it. Right now a big group of people are in a meeting discussing it, probably including Griffin, the CSO, the chief engineer, and a couple of the engineers most familiar with aerodynamics of the tank, vibrations during launch, and the properties of the foam. Is that somehow a worse reaction to the discovery of the crack than slashdot's "Oh no, something that's happened dozens of times before just happened again! We can't launch!" (cracks in the foam are nothing new, by the way).
One last point about the discussion of the in-flight presentations in you link. A big part of the problem is that some of the lower level engineers didn't appreciate the risks properly and therefore didn't convey them adequately. Instead, they focused on the rosier scenarios and the wording in their slides reflects that. One of the things that has been driven home since Feb 2003 is that risks must be appropriately understood at all levels of the organization. Assuming that this process may fail to catch a risk, NASA is now also performing detailed in-flight inspections of the orbiters to make sure damage did not occur during launch. Those are two of the "many problems" that have (theoretically) been fixed: risk communication and identification of risks-turned-problem.
As I understood it when this news was fresh (2 months ago...and yes Slashdot already covered it back then), the top NASA officials took a vote. The chief engineer and the chief safety officer voted not to launch until further work had been done. The rest voted to go because they didn't want to keep making change after change without a chance to test them, and evaluations of previous launches suggest that the foam which will probably fall from ice frost ramps in this launch will be in harmlessly small pieces that will fall in a way such that they miss the orbiter. The two who voted not to launch accepted these arguments and did not try to veto them.
These guys have enough authority and influence at NASA they can definitely speak their minds on this. Everyone at NASA, especially these guys, is keenly aware of the threat to the manned space exploration if something goes wrong with this flight. If they're not genuinely concerned enough to say more than "I'd rather not, but ok," then I'm not concerned.
HA! I knew it. I keep asking and people keep telling me that most of us don't have an accent to outside people. I couldn't understand how it could be possible that Welshmen sound so funny to us but we don't to them. Then again, Welshman probably sound funny to everybody, and a Texas accent and an American accent aren't the same thing.
Yes the feeling is mutual. If I may comment, however, I think the expectations for America are really high, partially because of our own pride, partially because of a blessedly prestigious history. I think any country is a place that contradicts and astounds in its own ways.
Since I haven't found a good place to whine about this yet (I hadn't noticed yet when the new layout first debuted), I'm going to digress a little further: Why does slashdot break the status bar?
Normally when you hover over a link, the status bar displays the URL, but in the new layout, some magical javascript immediately clears that information. It's nice that they offer the title showing what domain the link is on, but I prefer to know a little more specifically where it is before I click a link posted by one of a million possibly psychopathic nerds on this site. Breaking the status bar almost ranks up there with breaking the back button in my book, and I think it's worse than using marquee or blink elements.
Wrong on both number of flights and cost. The fixed costs of a shuttle launch are roughly $55 million. Higher numbers (up to $1.3 billion if you divide every penny budgeted to the program by the number of missions) include research, development, and construction costs as well numerous facilities, training, miscellaneous staff, and sometimes payload. In comparison, a Soyuz launch costs somewhere around $50 million (I don't know what that includes, but I don't think it's everything). The Russians charge us $65 million for launches that we order. The $20 million figure is how much they charged Dennis Tito for his ride.
Soyuz is still a little under 100 manned missions total. They've had as many fatal accidents, but of course, fewer people involved in each. It's also gone through several major revisions.
Of course, both comparisons are a little unfair since Soyuz is a fraction of the size and complexity owing to its more limited purpose. The architecture is fundamentally safer, but it doesn't do as much. Furthermore, costs aren't quite the same in Russia anyway. One source I just googled up says engineers over there typically make around $14,000 usd equivalent per year, compared to $70,000 in the US. Between designing improvements, operations, maintenance, etc, labor is the biggest ongoing cost in the US shuttle program.
1.) Since you force me to make the point: at 17,000 mph the metric becomes about 0.005 fatal accidents per million miles for the shuttle.
2.) This would have meaning if the shuttle and commercial airliners both had the same goal. One is designed to travel miles, one is designed to travel up and down.
3.) A space shuttle in orbit could suffer a life-support failure, an O2 tank explosion (it's happened before), a meteroid strike, a computer glitch that sends it almost irretrievably out of control (ask John Glenn how fun that one is) or a plethora of other serious dangers.
4.) Of course no airline would touch the space shuttle. No one would even think of selling an airline space shuttles. The closest thing on anyone's mind, which is still not very comparable, is sending people with more money than they're quite sure what to do with on 5 minute joyrides on suborbital capsules. Airlines aren't interested in space anyway. They want to get people from NY to LA cheaply and quickly.
Finally, both of you are silly because you're comparing an 80 year old industry flying ordinary people who don't expect to be taking a major risk in vehicles that are tested up the wazoo before they ever fly a passenger and operate in a relatively consistent design environment (taking off and landing aren't really that much different from cruising and airline accidents have occured while cruising anyway), to a cutting edge research-oriented group flying people who pretty well know all the different ways they could die at any moment while riding in vehicles that have only 114 full-system tests total and operate in an environment ranging from a stormy launch pad to firey ascent to a cold vacuum to a 3000 re-entry (holy run-on sentence batman). You are right that it's a meaningless comparison, but that much is irrelevant to the decision to send up 7 men and women who have given their lives to this opportunity, know the risks and benefits, and had the risks driven home quite personally when their friends and coworkers died on the Columbia.
If you want a good metric, compare shuttles to other space launch systems. Soyuz comes close. It's only had two fatal accidents in flight in something like 60 manned flights, but it's also much less capable and has had the benefit of several major revisions.
All that said, we can do better. We've been practicing for 40 years. 2 fatal accidents in 114 flights beats the curve, but it doesn't inspire a lot of confidence. In all likelihood, continuing to fly the shuttles with proper maintenance would improve that number. In both cases we've confidentally identified the mode. One mode has been eliminated (more redundancy in the O-rings and no more cold-weather launches). The other has been significantly reduced and further work is being done. Still the shuttle is very complex and offers a lot of ways that small problems can become big ones, and largely for that reason, it is being retired and the successor will be very different.
Slashdot Mirror
Um, yeah...I'm pretty sure your local forecaster just looks at the temperature, pressure, and humidity maps provided by NOAA and says, "gee, that's high pressure and it's warm and wet. There's low pressure over here so I think that's going to move onshore and it'll be 54 and cloudy with a 62.7% chance of rain." Or depending where you actually get your weather, he just goes to NOAA.gov, types in the zip code, then spends the rest of the day preparing his fancy animations of the jet stream for the 7 o'clock news.
Anyway, I seriously doubt the scientists involved in this project have any delusions about telling us when good days are for a picnic in upstate New York in July of 2036. Right now we're at the point of predicting El Nino's and La Nina's based on looking at the long term patterns and comparing those to the ocean temperatures. Compared to the fantastic summary, this project is no doubt more along the lines of those predictions, but carried out further and perhaps made a little more specific. Instead of planning for El Nino weather to be slightly warmer and wetter in continental climate areas (if I remember right) this summer, they might tell us to expect average highs in the American midwest to be 1-2 degrees higher with 10% more rainfall than the average during July of 2010.
Personally, I'm more interested in extending the current 1 week forecasts out to a month or more and increasing the accuracy of short term forecasts. I think it's possible to make reasonable approximations of most of the effects you list. Then again, with articles like this, who knows what they're really up to.
The nitrogen is used to pressurize the hydrazine tanks to feed the reaction control system. It's pretty simple. Rather than have pumps that would be corroded by the hydrazine, they just warm up the nitrogen a little bit and the pressure increases. They know the pressure is dropping, but they're not sure if it's because they're losing nitrogen or losing hydrazine. I suppose they decided it wasn't worth the extra effort, cost, complexity, and weight to be able to isolate the tanks soley for the purpose of determining where a leak was, should one occur, so they just assume the worst case and prepare for that, if necessary.
Hydrazine wasn't chosen for performance. It actually has a rather low ISP. It was chosen for reliability. The reaction control jets have to fire repeatably far more times than other types, and usually while cold. In this case, NASA uses a hypergolic form; one which spontaneously combusts in the precense of another chemical. The two are released simultaneously into the reaction control jet and voila, fire.
NASA would love to develop a methane based version with a much higher ISP and less handling risk, but it got cut out of their CEV budget. I think now they're sponsoring a private company to develop one via the COTS program. It would have to be actively ignited, which raises reliability concerns. I'm not sure what other design problems are holding it up.
Hydrazine reacts in the precense of a catalyst such as silver or iridium, which is why combustion chambers of many reaction control rockets are lined with such. Hydrazine is semi-stable. It will breakdown in the precense of the catalyst or if it warms up to the proper point. If neither happens, you're fine. The engineers who actually know how the system is designed (ie, not you), and know where stuff can get into, where it might come into contact with a catalyst, or where it might warm up are the ones qualified to analyze the risk.
As for the risk of explosion, well that's poorly written, but if you don't have enough to cause a pressure increase of damaging magnitude, well then there's nothing to worry about. In this case they have a lot less. That suggests to me they looked it over and decided it must be leaking in a way that there's no place for it to accumulate.
Furthermore, according to NASA, they don't actually use pure hydrazine in the shuttle RCS jets. They use nitrogen tetraxide and monomethyl hydrazine (add on a carbon atom), which are hypergolics. They're more stable but they react spontaneously in each others presence.
Of course, the shuttle engineers don't have a clue about any of this. They like playing dice with their co-workers lives.
Hmm...the military has been working on this for years to destroy tactical missiles and artillery rounds in flight. I'd be very surprised if it shows up at airports before it shows up in air defense artillery units.
(The links I provided describe intermediate systems. One is a developmental laser. The other is not capable of engaging aerial targets).
It seems this point has to be made 3 or 4 times every time a submission about Bigelow comes up...and people still don't believe it. Zodiak boats are a perfect example of a robust inflatable structure. Another good example is a tire. Compare the impact resistance of those things to a thin sheet of aluminum!
The inflatable module is really only different in that uses air pressure to maintain its shape instead of framework (actually, there is a framed core down the middle with avionics and inflation equipment and to support mounting equipment inside the pressurized portion...also similar to Zodiaks). The skin is several layers of different insulating, containing, and protective materials. Some of these are tougher than Kevlar! The result is a module that is (hopefully) stronger by weight than equivalent rigid capsules, has more interior volume, and fits in a smaller launch fairing.
Along with the confusion about the vulnerability being similar to a balloon, people also get confused about the volume. Unlike a balloon, it doesn't grow to several dozen times its packed volume. I think it's closer to a factor of 2 or 3, depending on the model. It won't revolutionize living in space, but if it lives up to its potential, it will be another step in the right direction.
FYI, NASA originally started development work on the technology under the Spacehab project to be used for one or two modules on the ISS. Due to budget constraints and time limits, they chose the traditional modules and set the development effort aside until Bigelow bought rights to the technology. The technology might also see applications in long-term lunar or Martian bases.
Actually, bad article, too. Wonders never cease.
The satellites the "article" talks about are the result of MIT and DARPA's Synchronized Position Hold Engage and Reorient Experimental Satellites (SPHERES...sounds like they were stretching a little bit to get decent sounding acronym). The immediate focus of research is to develop control systems for automated docking, with later potential applications of station-keeping and maybe even satellite repair. For example, you may recall a DoD satellite repair mission that failed last year when the robot failed to latch on to the target satellite and accidentally bumped into it before running out of fuel.
The SPHERES are tested inside the ISS and manuever using cold gas thrusters (standard CO2 bottles, I think). The goal is for them to maintain alignment with a hand held beacon that the astronauts move about inside the station. For this generation, I believe the beacon is auditory based. Obviously that won't work outdoors, but this is a pretty low-cost, basic level development effort.
You're wrong on pretty much the entire post. There are quite a few different types of radiation shields, or more relevantly, radiological protection.
The simplest is something that blocks radiation (the electromagnetic kind, not the imaginary magical glowing stuff you see in scifi channel specials or referred to by greenpeace activists with a degree in philosophy). Sunglasses are an example I hope most people are familiar with. They block a limited range of wavelengths, typically in the UV, to protect the eyes. In reactors, gamma rays (high energy radiation) are typically blocked by heavy atoms (lead) or thick layers of concrete and steel, or a combination. 2 feet of concrete reduces gamma radiation flux to 0.1% of incoming intensity.
Then there is protection against beta particles (high energy electrons) and alpha particles (radioactive helium isotopes). These are far easier to contain than gamma rays due to their mass, and lightweight materials like a thin layer of aluminum or many plastics are sufficient. Gamma radiation is often produced from "braking" of high speed electrons or decay of helium isotopes, but we already dealt with that above. Beta particles and alpha particles are not technically radiation, but they are radiological threats.
Neutron bombardment is probably what you were thinking of. Neutrons are released during fission and absorbed by other atoms, making the nuclei unstable and causing further breakdown, perpetuating the chain reaction. Neutrons are also, however, absorbed by surrounding material such as the steel casing and control rods, doping those materials to form radioactive isotopes. As a result, these parts, all of which are inside the reactor vessel as opposed to all over the entire plant like you claim, become low-level radioactive waste when the vessel is decommissioned. Decommissioning has to be done, not because the whole thing becomes so radioactive it's dangerous to operate, but because neutron bombardment causes the metals to become brittle and less structurally sound.
Re-reading your post, I think you're confusing what you've read about the aftermath of the Chernobyl accident with typical plant operations. Chernobyl is completely different because the radioactive particles (a little bit of alpha particles, mostly radioactive fuel, reaction products, and neutron bombarded reactor materials) escaped the containment structure due to the explosion. Once scattered around the countryside by the explosion and weather, their proximity (especially when ingested) is what caused problems like thyroid cancer and, immediately after the accident, radiation sickness. The one hour rule was workers in the zone when they were building the "sarcophogaus" over the remains of the reactor. You've probably heard the claim that a person living a mile downwind from a nuclear power plant receives less radiation than if they watched an extra hour of TV per day. The ground is fine. Certainly not radioactive. The Trojan plant 40 miles from my house is currently being decommissioned. 15 years from now, when that's done and the last of the low-level waste is removed from temporary storage and taken to a long-term repository, the site will be a park.
The one problem left, that you actually almost did get right because it's a cost that wasn't initially appreciated (currently there is a tax on nuclear-generated energy to cover it), is the waste fuel, by-products, and reactor that have to be disposed of. The material is sorted by radioactivity and type and disposed of in various ways. This is pretty complicated, so I'll just describe the nastiest threat, which is the spent fuel. It's chemically processed into a solid, chemically stable ceramic that is not water-soluable. This is then encased in steel and further encased in reinforced concrete and will eventually be buried 1000 feet underground in a federal repository. Degredation of the containers in the next 10,000 years is unlikely, after which the most radioactive stuff will have decayed. Contamination by natural mea
Of course, the *AA's have circumvented the roughly equivalent precendence in the car analogy by arguing that the user does not buy content. Instead they maintain that you buy or lease a license (or something to that effect) to access the content. Ownership of the content remains in the hands of the creator. This much doesn't seem overly outrageous to me. My problem is when they tell me how I will access the content. I can't think of any good car analogy for this.
Arguring for this limitation is motivated by the fact that it is possible and even easy to violate the terms of the claimed license by making copies and giving them to your friends, etc. There doesn't seem to be too much disagreement that this sort of behavior should be illegal. However, the lawyers are attempting to shift the problem from being about people who do perform an illegal act to people who can perform an illegal act. A car analogy would be: because I can use a leatherman to hot wire a car, I should not be allowed to own a leatherman. Actually, in retrospect, we're talking about intellectual property rather than physical property. Perhaps I should say that because I can use a digital camera to steal design details from Ford, I shouldn't be allowed to own a digital camera. For that matter, perhaps I shouldn't be allowed to own eyes. And since I can use my ears and voicebox to capture and replicate (in even more painful fashion that Britney Spears, I admit) "Oops I did it Again," maybe I shouldn't be allowed to have those.
I believe this kind of restriction is called pre-emption. In some cases it is considered legitimate. For example, we don't let people have unlicensed explosives, not because they will blow something up, but because if they do, the damage will probably be significant and potentially irrepairable. On the other hand, if I steal a movie (actually, watch an unlicensed movie), I've deprived the content owner of $15 and nobody died. Regulating piracy my way (prosecuting the guilty) might not engender as much obedience of the relevant laws and therefore some amount of increase in losses due to piracy. Regulating that the MPAA/RIAA way (crippling the innocent) could mean a very significant loss of freedom for users to not only play licensed to content, but also to develop and distribute new content. It also has a cost in terms of required features to support DRM and other similar encumberments. Given the balance of these factors, pre-emption seems to me like a terrible policy for controlling piracy.
Well, if it turns out that some particular group of us is right and you will someday meet your maker... (I'll leave off at an ellipse rather than risk sparking a discussion over who might actually be right).
I'm a little perplexed by the intermingling of the terms "piracy" and "other side of the coin."
The use of the term piracy suggests (although I won't say it's definitive) that something illegal is being done. Talking about the other side of the coin would then seem to be making a claim it's ok to do bad if something good comes out of it, which I suppose is worth considering if the "net good," for lack of a better term, of piracy exceeds that of legal use. However, I'm letting myself digress. If people want to argue their case as a form of fair use, then calling their own actions piracy does not help others to see it as something other than stealing. When I hear people talking about the other side of the piracy coin, I think of a parallel along the lines of how the predation of US merchant ships by the Barbary pirates must've been good for the economy of Tripoli, and therefore should be allowed.
Digressing again, I was disappointed by Techdirt's contention that "piracy" was ok because it changes the business model by making recorded music a promotion for concerts and other more tangible products. My problem here is that they're attempting to dictate the business model that the entertainment industry should adopt, rather than allowing them to stick to their "increasingly obsolete" (techdirt's term) business model and running themselves into the ground while more progressive companies take advantage of the changes (assuming the new business model actually is superior (and how is that superiority quantified, anyway?)). Besides, concerts cost too much as it is.
That's a fun one!
I don't know how old you're client was, but I have a pet theory that the reason our grandparents can't handle VCR's or computers is because they're used to farm machinery and exposed gears, where if you screw up because you don't really know what you're doing, somebody gets maimed or killed. They don't like messing with things they don't fully understand.
With computers, screwing around with something that you don't get just means losing a little bit of data or picking up a virus.
Rinkworks has a great collection of stories. I question the veracity of some of them, but they're still funny. When I first discovered it, I had to stop after a couple pages because I was losing my faith in mankind's ability to not be completely hopeless.
The Register's list has a couple good ones (The hungry floppy drive is my favorite), but some of them seem rather lame given the number of stories out there, and they're written like they were copied and pasted from a chatroom. Example: "Someone telling me their 'broadbean' connection is down." I would even say that my 9 year old can write better than that, except I don't have a 9 year old son.
Also, I'm sorry because I know how important this topic is to Slashdot, but "Girl from HR with large chest walks in to department..." (more spectacular writing) doesn't exactly strike me as a bewildering IT anecdote. It's more like someone got excited about directly interacting with the HR girl and felt a need to share their excitement with the Register.
Along the exact same lines: "Damn the torpedoes! Full speed ahead."
Farragaut didn't have time to prance about in the minefield at Mobile Bay while being shot at by confederate ships and shore batteries. In fact, I don't think any of the ships hit mines except for the USS Tecumseh, which discovered them in the first place.
Soyuz has an ablative heat shield. It's probably made of some sort of ceramic, formed into 8 layers called "blankets" (I think they're only flexible enough to allow for expansion and contraction of the spacecraft, not like a quilt). The capsule is single use, so the heat shield only needs to survive one re-entry, and the exposed surface area is small, reducing overall weight. The ablation (burning away of small particles) carries heat away from the capsule. A similar system has been used on pretty much every entry system except for the shuttles, even the Mars rovers. The Russians did use a system nearly identical to the space shuttles for their Buran shuttle, which was abandoned after one flight due to budget problems.
The weight and maintenance of an ablative heat shield were prohibitive in a very large reusable system like the shuttle. Instead, the leading wing edges and nose of the shuttle are protected by reinforced carbon-carbon tiles, the underside by ceramic tiles that are in some ways similar to aerogel, and other sensitive areas by a heat resistant cloth. The carbon-carbon is the most effective and actually pretty strong, but about 6 times more dense than the other options. Read more.
In short, no the Russians haven't had fatal problems with their thermal protection, but it's not feasible for a vehicle like the shuttle.
Sorry to piggyback on a joke. This is the actual status, copied from NASA's shuttle page
It sounds like "crack" isn't a very descriptive term. A small piece broke off, probably due to the weather-related causes. They're trying to decide if they need to erect a platform to do a hands-on inspection.
On the source page there's a picture that took me a minute to figure out, so I'll explain it. The solid orange to the left is the main body of the external tank. The round orange vertical item in the center of the picture is the LOX feed line. The big metal piece is probably part of the tripod mount. Just below and to the right of the mount is one of the brackets that holds the LOX line in place, covered in foam. Looking closely, you can see a little triangle of white where the little chunk (about 4 long) of foam spalled off. I assume the T-shaped feature to the right of that is the so-called ice/frost ramp, which they're concerned may be at risk for falling off in flight. It's much clearer in the high res picture linked on that page.
At first glance, it doesn't look like a concern at all, but obviously NASA wants to make sure of that. If anybody has serious reservations, they'll setup a platform to get somebody who knows what to look for up close to it and look for evidence that this may increase chances that the ice/frost ramp or other pieces of foam may fall (smaller cracks, loosening of the frost ramp, etc).
For comparison, this piece of foam is estimated at 0.0057 pounds and may be as large as a cellphone. The piece that struck Columbia's wing weighed an estimated 1.67 pounds and was described as "briefcase-sized"
(Also, the joke is 2nd Tuesday of next week. Your rendition makes about as much sense as a screen door on a battleship)To the best of my knowledge, that is not true. Look at the crew roster. All but one (a doctor in biometeorology for ESA) have engineering degrees, and almost all of them have masters or doctorates.
Also, they effectively do have a say. Nobody is holding a gun to their head. If they truly felt the risk was unacceptable (keeping in mind, however, these guys happily take risks most people find unacceptable), they could refuse to go.
Furthermore, and the astronauts no doubt realize this, despite their educational background and technical understanding, they are seldom in the best position to make the final call. They know the STS pretty well and provide input on some of the major decisions, but really the guys who should make the final calls are the administrators based on the recommendations of the engineers who know most about the relevant issues. In this case, they are seeking recommendations from the engineers who know most about the foam. In the end, the astronauts have to trust to some degree that these guys know what they're doing, so if they don't trust them or they feel sufficient reservation (enough to overcome their own drive to succeed) about the administrators decisions, they simply won't suit up.
The shuttle's got something like 10 million parts. If Joe Engineer tells Frank Skywalker that doohickey 3178219 is 1.6 mm out of tolerance and it'll take a week to make a new one, Frank isn't going to be say "Oh no, things should be in tolerance. I'm not getting on that thing." He's going to ask the engineer what ramifications this might have for the mission and if he should be concerned, to which Joe might reply, "Well, it might make the toilet seat squeak when you try to put it down. No worries." Given the complexity of making a go/no-go call in the foam case, it drives me up the wall to see some of the other comments from slashdotters not involved with NASA and often probably not with a mechanical engineering education criticising NASA for even considering launching when there's a small crack in the foam and we don't even know yet if it will affect the shedding or not.
Actually, the discussion right now is whether or not a 4-5 inch crack actually is something to sneeze at. Cracking in the foam is not a new occurance. No doubt there's a bunch of engineers running CFD analysis like mad right now trying to figure out how much extra stress the crack exposes the foam to and whether this actually does increase the likelihood of shedding or not. If the crack is on a sheltered face, it might have no effect. It is even remotely possible that the crack formed in the process of relieving some residual stress and in that case possible that it's a little better off now, although it's doubtful the analysis would be able to determine that. Furthermore, attempts to fix it may actually make the problem worse by stressing the crack with new material. As you can see, it's not an easy question to address.
Also, there's several problems with foam inside the tank. Number 1 is manufacturing and inspection difficulty. The tank has to be sealed off after the foam is applied, which could affect the foam and we'd have no way of knowing. If for any reason the integrity was severely effected, you could still get ice on the outside of the tank. Number 2 is weight. Putting the foam inside the tank enlarges the structural volume accordingly, making the tank heavier. Number 3 is isolation. I mean protecting the foam from the fuel, which also means more weight. If the fuel is directly exposed to the foam, it can soak in, first of all making it effectively unavailable to burn, and secondly significanly reducing the insulating value of the foam (think about how cold a wet sweatshirt is on a cold day). Also, you really would not want a piece to fall off and get sucked into the turbopumps or for the foam to react with the fuel. Number 4 is the miscellaneous hardware. None of the foam that is a concern would be suitable to place inside, although it turns out that it may be acceptable to remove the highest risk portions. The tripod ramp and the proturbance air load ramp foam have been removed. This crack formed on an ice frost ramp on the brackets that hold the pipes in place, but NASA's not yet comfortable with the aerodynamic changes that would result from removing that, and foam falling from that region either has not been observed to strike the orbiter or has been really small pieces if it has. The ice frost ramps may still be removed for the next flight.
I don't fear for the space program if Discovery were to be lost. It would hurt it for sure, the shuttle may be immediately retired, and I doubt the ISS would ever be finished, but NASA and even manned spaceflight would still continue. Theoretically though, the chance of a problem on this flight is lower than possibly any previous flight. Every major concern has been addressed to some degree, as have many of the minor ones. There's backup plans ready and an unprecendented level of procedure in place to identify any problems if they do occur. There is still risk, but I argue less than on the 114 previous flights.
This is different from other organizations how?
Honestly, senior managers don't have time to review every minor detail of every project. This kind of structure works as long as people at the lower levels are competent to know what information is relevant to pass along, how much information their superiors can handle at once, and what makes a critical bullet point. If you watch the interviews and press conferences, you'll notice Griffin and the other top NASA officials have a pretty good handle on what's going on. It certainly doesn't hurt that Griffin is an experienced engineer himself and understands the technical side of the operation better than his predecessor.
Also, what are the "many problems" you refer to? I'm not saying there's no problems, but I've seen a lot of things fixed in the last 3 years, so I'm not sure if there's anything specific you're referring to, or if you just thought you'd join in the NASA-bashing. It's not like we know about the foam crack, but through some marvel of a broken communications structure at NASA, the top people are utterly unaware of it. Right now a big group of people are in a meeting discussing it, probably including Griffin, the CSO, the chief engineer, and a couple of the engineers most familiar with aerodynamics of the tank, vibrations during launch, and the properties of the foam. Is that somehow a worse reaction to the discovery of the crack than slashdot's "Oh no, something that's happened dozens of times before just happened again! We can't launch!" (cracks in the foam are nothing new, by the way).
One last point about the discussion of the in-flight presentations in you link. A big part of the problem is that some of the lower level engineers didn't appreciate the risks properly and therefore didn't convey them adequately. Instead, they focused on the rosier scenarios and the wording in their slides reflects that. One of the things that has been driven home since Feb 2003 is that risks must be appropriately understood at all levels of the organization. Assuming that this process may fail to catch a risk, NASA is now also performing detailed in-flight inspections of the orbiters to make sure damage did not occur during launch. Those are two of the "many problems" that have (theoretically) been fixed: risk communication and identification of risks-turned-problem.
As I understood it when this news was fresh (2 months ago...and yes Slashdot already covered it back then), the top NASA officials took a vote. The chief engineer and the chief safety officer voted not to launch until further work had been done. The rest voted to go because they didn't want to keep making change after change without a chance to test them, and evaluations of previous launches suggest that the foam which will probably fall from ice frost ramps in this launch will be in harmlessly small pieces that will fall in a way such that they miss the orbiter. The two who voted not to launch accepted these arguments and did not try to veto them.
These guys have enough authority and influence at NASA they can definitely speak their minds on this. Everyone at NASA, especially these guys, is keenly aware of the threat to the manned space exploration if something goes wrong with this flight. If they're not genuinely concerned enough to say more than "I'd rather not, but ok," then I'm not concerned.
Yeah, I guess I hadn't noticed at home where I use Firefox because there was nothing to notice. It seems to be IE only.
HA! I knew it. I keep asking and people keep telling me that most of us don't have an accent to outside people. I couldn't understand how it could be possible that Welshmen sound so funny to us but we don't to them. Then again, Welshman probably sound funny to everybody, and a Texas accent and an American accent aren't the same thing.
Yes the feeling is mutual. If I may comment, however, I think the expectations for America are really high, partially because of our own pride, partially because of a blessedly prestigious history. I think any country is a place that contradicts and astounds in its own ways.
Since I haven't found a good place to whine about this yet (I hadn't noticed yet when the new layout first debuted), I'm going to digress a little further: Why does slashdot break the status bar?
Normally when you hover over a link, the status bar displays the URL, but in the new layout, some magical javascript immediately clears that information. It's nice that they offer the title showing what domain the link is on, but I prefer to know a little more specifically where it is before I click a link posted by one of a million possibly psychopathic nerds on this site. Breaking the status bar almost ranks up there with breaking the back button in my book, and I think it's worse than using marquee or blink elements.
That's my big nitpick for the day.
Wrong on both number of flights and cost. The fixed costs of a shuttle launch are roughly $55 million. Higher numbers (up to $1.3 billion if you divide every penny budgeted to the program by the number of missions) include research, development, and construction costs as well numerous facilities, training, miscellaneous staff, and sometimes payload. In comparison, a Soyuz launch costs somewhere around $50 million (I don't know what that includes, but I don't think it's everything). The Russians charge us $65 million for launches that we order. The $20 million figure is how much they charged Dennis Tito for his ride.
Soyuz is still a little under 100 manned missions total. They've had as many fatal accidents, but of course, fewer people involved in each. It's also gone through several major revisions.
Of course, both comparisons are a little unfair since Soyuz is a fraction of the size and complexity owing to its more limited purpose. The architecture is fundamentally safer, but it doesn't do as much. Furthermore, costs aren't quite the same in Russia anyway. One source I just googled up says engineers over there typically make around $14,000 usd equivalent per year, compared to $70,000 in the US. Between designing improvements, operations, maintenance, etc, labor is the biggest ongoing cost in the US shuttle program.
1.) Since you force me to make the point: at 17,000 mph the metric becomes about 0.005 fatal accidents per million miles for the shuttle.
2.) This would have meaning if the shuttle and commercial airliners both had the same goal. One is designed to travel miles, one is designed to travel up and down.
3.) A space shuttle in orbit could suffer a life-support failure, an O2 tank explosion (it's happened before), a meteroid strike, a computer glitch that sends it almost irretrievably out of control (ask John Glenn how fun that one is) or a plethora of other serious dangers.
4.) Of course no airline would touch the space shuttle. No one would even think of selling an airline space shuttles. The closest thing on anyone's mind, which is still not very comparable, is sending people with more money than they're quite sure what to do with on 5 minute joyrides on suborbital capsules. Airlines aren't interested in space anyway. They want to get people from NY to LA cheaply and quickly.
Finally, both of you are silly because you're comparing an 80 year old industry flying ordinary people who don't expect to be taking a major risk in vehicles that are tested up the wazoo before they ever fly a passenger and operate in a relatively consistent design environment (taking off and landing aren't really that much different from cruising and airline accidents have occured while cruising anyway), to a cutting edge research-oriented group flying people who pretty well know all the different ways they could die at any moment while riding in vehicles that have only 114 full-system tests total and operate in an environment ranging from a stormy launch pad to firey ascent to a cold vacuum to a 3000 re-entry (holy run-on sentence batman). You are right that it's a meaningless comparison, but that much is irrelevant to the decision to send up 7 men and women who have given their lives to this opportunity, know the risks and benefits, and had the risks driven home quite personally when their friends and coworkers died on the Columbia.
If you want a good metric, compare shuttles to other space launch systems. Soyuz comes close. It's only had two fatal accidents in flight in something like 60 manned flights, but it's also much less capable and has had the benefit of several major revisions.
All that said, we can do better. We've been practicing for 40 years. 2 fatal accidents in 114 flights beats the curve, but it doesn't inspire a lot of confidence. In all likelihood, continuing to fly the shuttles with proper maintenance would improve that number. In both cases we've confidentally identified the mode. One mode has been eliminated (more redundancy in the O-rings and no more cold-weather launches). The other has been significantly reduced and further work is being done. Still the shuttle is very complex and offers a lot of ways that small problems can become big ones, and largely for that reason, it is being retired and the successor will be very different.