All it takes is a well-aimed bucket of gravel in the right orbit to take out a space-based system. Launching buckets of gravel is pretty cheap, so unless the US system is 100% effective, this system will suffer from the same flaws as the anti-missile system - it's easy to overwhelm it with a lot of cheap countermeasures.
IIARS.
Technically, that's true--the math's pretty easy, so planning an orbital interception's not at all hard. Actually being able to carry it out is the hard part. You can't just put your bucket of gravel in the same orbit as the bird you want to destroy; everything in the same orbit is going the same speed. It has to--laws of physics and all. You really can't put it in a retrograde orbit, either, and smack it from the other side, as you'd have to negate the initial velocity from the earth's rotation, and that's not insignificant.
So you have to put your gravel in an orbit that will intercept the satellite's orbit. Assuming this bird is in low earth orbit (LEO), which is a safe bet, this is pretty easy to accomplish. Put your gravel in an elliptical orbit with the perigee matching the target bird's orbit, and make sure they'll get there at the same time.
That's the easy part, and it will get you close. The actual intercept, however, is where it gets hard. Space is big. Really big. All those satellites would be bouncing off each other all the time if it wasn't. A direct impact will require precise manuvering. That means a real orbital vehicle with manuvering thrusters, some kind of autonomous guidance system (inertial, startracker, etc.), and a terminal guidance package (probably radar). Even then, the velocities involved are very high--we're talking differences in kilometers per second, here--and a near-miss won't cut it. This is why the old kill-sats from the Cold War were designed with nuclear weapons on board. Close with a nuke is close enough.
Even with such a weapon, a successful intercept is not assured. We'd know something was coming well in advance. We've got some good reconnaisance satellites, so we'd see the thing sitting on a pad (orbital rockets are pretty big, and there's only so many places in the world that can launch them). Even if we managed to miss it, we'd see the launch, since watching for booster plumes (and nuclear explosions) is the primary purpose of more than one satellite sitting way up in GEO (geostationary orbit). Once we saw it coming up, US Space Command would know what kind of orbit it was in. If it looks dangerous or suspicious, they'd be ready for it. Just wait until the killsat is established on its final intercept course, and we kick our bird with some random delta-V. The other guy's intercept is now shot to hell, he likely won't have the fuel to try another one, and he's just pissed us off. We're out some manuvering fuel. Precious as on-orbit hydrazine is, it's better to expend it than have your whole satellite 'expended' for you.
NORAD and USSPACECOM are good. They played and plotted against the Soviets, and no one else these days plays near so good a game.
There's no such thing as 'cheap countermeasures' when you have to put them in orbit. There are precious few effective countermeasures, and they're anything but cheap.
"Hey, guys--bad news. Turns out we were using the consumption rates in gallons of oxygen per minute, when we thought we were using liters! Heh, sorry about that."
Except that you're more likely to have your gun pointed at you than you are to point it at someone else. I'd much rather take a 10% forward firing failure rate to reduce the chances of backfire by 100%.
I hear this statistic a lot, and it may actually be true. I don't think so, as the vast majority of defensive uses of a firearm result in a shot never being fired (that's the hypothesis, anyway)--consequently, the 'good' uses don't get reported.
Anyway, let's assume your statistic is, in fact, correct. I'd attribute this to people being stupid, so I don't have much sympathy. The only place for a gun, when it's not on your person, is in a safe--and a loaded gun in a safe is perfectly, um, safe, as it can't shoot anyone on its own. Perhaps at your bedside, while you sleep. If someone can break into your house, retrieve your loaded gun, and kill you with it, without you ever waking up, something else will probably kill you in your sleep eventually anyway. I dunno, a fire or escaped tiger or something.
Someone's breaking in? Rack the action on a shotgun, and I guarantee they'll haul ass out of there. A shotgun is more fearsome than an assault rifle, close-in, and criminals damn well know it. Anyone who doesn't run away from _any_ kind of drawn firearm can be assumed as intending to kill you. Keep your gun between him and your family, and call the police. If he makes off with the television, so be it. That's what insurance is for. If he comes toward you, warn him off--if he takes off, great. No one wants someone's death on their conscience, even if it's a scumbag. But if he keeps closing with you, he's going to fucking kill you.
This is not the time to worry whether the batteries in your gun are charged, or whether that papercut on your finger will false-negative the sensor. You want the simplest mechanism possible to throw those bits of lead at the other guy.
Anyone who can't be at least this responsible has no point owning _any_ kind of gun, smart or not. I see this causing people to respect the terrible destructive power contained in that small package even less than some idiots already do. This mechanism can fail both ways, just like manual safeties do. If you're nonchalantly waving the damn thing around when that happens, or leave it where your kids can get at it (it's 'smart', after all, so no accidents will happen, right?), it's going to punch a hole in something important.
I'm generally all for technology, but not here--education is the key.
Sorry, this might sound like a troll, it's not. Is your country really that f*ck*d up that people feel they aren't safe without weaponry? Your use of the word "necessary" seems to indicate that things are pretty screwed up where you are.
Surely this is an over exaggeration isn't it?
Don't I wish. The courts have long upheld that the police have no legal responsibility to protect individual persons--rather, their job is to attempt to enforce the laws on the books and just generally 'show the flag'.
Back when I was still in school, I was with a volunteer rescue squad. Emergency medicine, vehicle extrication, stuff like that. I spent a year living in one of the stations (no rent, just keep the truck in service). I noticed some holes in the front wall right after I moved in. Inquiries revealed that they'd come from a rifle shot from a passing car (it was a cheap modular building, so it went out the back wall, too). This was in a pretty rural suburb, without much in the way of crime.
The three people inside called the police and hid, hoping no one was going to come kicking their door in before they got there--many people were under the mistaken impression we had some cache of narcotics stored there for medical use (we let the ambulances carry those for us), so we had to worry about junkies breaking into our vehicles and buildings.
Luckily, nothing like that happened, as a cop car didn't roll up for twenty minutes. He'd been dispatched as 'investigate shots fired at an abandoned building'--a non-priority response. Had it been an actual robbery/home-invasion...
I applied for a firearm carry permit the next week. Yes, it can be that screwed up over here (I'm speaking of the US). I've never drawn a gun in anger, and I hope to God I never have to. But just reading the newspapers makes me glad I've got the ability to meet force with force--better to have it and never need to use it...
So I'll echo the OP--this is a bad idea. I prefer my.45--entered service with the US military in 1911, and was used until they standardized on 9mms with NATO in 1985. It's been proven reliable, and you can completely disassemble it using no tools. THAT is what a defensive weapon should be. A solid chunk of stainless steel--not something you have to worry about shock damaging the electronics. Not when your life is on the line. It would be better to just not let the bad guy get ahold of your gun. (Seriously--there's courses on weapon retention for just this reason).
Remember the Netscape fishtank? I remember how cool I thought that was, back when I first started using Netscape (v. 2.02, I believe). Just a static image of the fishtank in their lobby that would be updated every 60 sec. or so, and not much to get excited about these days.
Diesel engines are pretty constantly turning low RPMs, and the fan systems are designed for that. I have yet to see a system of electric fans that will work as well as the one large belt-driven fan mounted on my truck. The thing sounds more like a propeller.
Electrics are great for cars and smaller trucks, but when you really start up the displacement ladder...
My apologies--I'm used to dealing with my less mechanically-inclined friends. I would be interested in the vehicle type, as I've not heard of such a system. Then again, my power steering pump drives my brake assist, so I'm sure it's possible.
Electric fans are great for smaller engines. Most of these are mounted transversely these days, so that's about the only kind of fan available. Large engines in trucks, though, are a bit harder to fit with an electric fan. Towing vehicles, especially. I've known people to try using the largest available as replacements, and most have experienced overheating. For sheer airflow, it's hard to beat a large engine-driven (through a clutch) fan.
You think that's scary? There are actually cooling fans that run off the power steering pump. Talk about bizarre. If your power steering fails, your car overheats.
I don't think that's quite how it works, at least on any vehicle I'm familiar with. There are one or more belts on the front of most engines. At least one is connected to the crankshaft, and power is distributed from there to the pulleys that run the airconditioning, alternator, power steering, water pump, fan...
They're connected, yes, but the fan is driven off the crank, just like the PS pump.
If you shut off the engine, you will lose your power steering, as it's powered by an engine-driven pump. Since all you need to do is turn a few degrees to the side to guide it to the shoulder, though, the manual fallover works just fine.
Most power brakes are run by engine vacuum (some, like my truck, are a hydroboost system off the power steering pump). There's generally (actually, I think it's required by law) an accumulator that will store engine vacuum. You get at least two or three full-pressure applications before the vacuum is exhausted, and then it's fallover to the unassisted hydraulic brakes--you can still stop, it'll just take longer.
My truck weighs in excess of 7000 pounds (3175 kg), and I can easily control it with the engine off (one of the first things I did after buying it was get it up to speed in a parking lot and shut it off, to see how it handled).
Just shut off the engine, put the transmission in neutral, keep steady pressure on the brakes (pump them, and you're out of power assist in short order), steer to the side of the road. Just don't turn the key to lock, or whatever causes the steering column to lock in place--there should be an interlock requiring you to push a button or press in the key to do that, anyway.
This should be a non-event. Broken steering shaft, or an old straight-air tractor-trailer with an air system failure--there's something to be excited about.
Traffic in the sky won't multiply by 10,000x, because this will never catch on. There aren't that many people willing to go through the expense and difficulty of learning how to fly (even if it's much more simplified than common light airplanes) and getting licensed.
As far as blending in to traffic, you can do that with a rental truck, too--and I assure you, it will hold far, far more explosives than any light airplane or flying car. You can't pack enough stuff in a small aircraft to make a dent in anything important.
And by the way, you can't necessarily track any single vehicle in the sky now. Most civil radar installations will pick up an aircraft, but you only get azimuth and range, with no altitude info or identification. That's what the transponders in the airplanes are for (they reply when interrogated with the altitude as reported by your altimeter and with the 'squawk' code you've entered--1200, unless they give you a new one), and you can turn them off. Don't want them to know who you are? Stay off the radio, turn off the xpdr, fly low--reminds me of all those Microprose sims I played back in the '80s, but military surveillance and fire control radars are a bit nicer than the ASR and ARSR sets the FAA operates--they generally don't have to deal with aircraft that don't want to be found, and there's plenty of airspace left that's uncontrolled.
Really, though--it's like worrying about people on bicycles or motorcycles being able to blow up a building because they can get around the crash barricades set up to keep trucks out. They can get in, sure, but not carrying enough of anything to do any real damage.
And it's far easier to break into and hotwire than a car.
What I'm trying to say is that it's child's play to steal a light aircraft. Many of these old Cessnas are 40 years old--yeah, the doors lock, and there's an ignition key, but either one is easier to defeat than those on my truck (which I've had to break into a few times, with nothing more than a flat strip of aluminum, notched at the end).
People are sparse at some of these fields, and many airplanes are not in hangars, but just tied up in the grass, or an incomplete strip hangar that provides only a roof. Access is easy, getting in the airplane is easy, and unless someone working at the FBO (Fixed Base Operator--they sell fuel and stuff) sees you breaking in or notices that someone different is flying that plane today, you can just fly away with no one the wiser.
Reference that kid who stole an airplane from the St. Pete/Clearwater Airport about 2.5 years ago. Hell, they knew he wasn't supposed to be flying the airplane, and the Coast Guard (also based there) managed to get a helicopter after him while he was rolling down the runway, but he still managed to fly to downtown Tampa (over MacDill AFB, home of US SOCOM and CENTCOM) and crash into the Bank of America Building. Luckily for them, a Cessna 172 is pretty light, and he managed to take out a window and knock down a cubicle (plane didn't even make it all the way inside).
You don't need a full pilot's license for some recreational aircraft, and you likely won't need one for fying cars either.
Correct--but you do need a pilot's license. It's been a few years since I looked into it, but used to be the Recreational Pilot Certificate was the lowest-grade pilot's certificate one could obtain in the US (Private Pilot being the mark most people aim for initially). There are restrictions on aircraft size (hint--it's small), carrying passengers, airports that can be used, more stringent weather minimums, etc. They've issued few of these to date, as the requirements aren't much less than for a Private cert, so why bother?
There's been a motion for years to create an easier-still certification, and this may have recently come to fruition. The restrictions here were pretty severe--going from memory, there's only a handful of aircraft small enough to qualify, you only get one passenger, can't fly at night, etc. (if anyone knows better, please chime in).
But when you consider all that, keep in mind that you still need something like 20 hours of instruction (minimum) and passing several exams (written and practical) before you can fly. This ain't a driver's license--it requires no small amount of skill and training to fly, let alone land, one of these. Plus, these 'recreational' aircraft are tiny. A Cessna 150/152, for example--long a mainstay of primary flight training--has enough room for two people up front, generally with shoulders touching the side windows and each other, and a small bit of room behind the seat for a bag or two. A Mazda Miata has more room inside, and weighs quite a bit more, as I recall. If they made these flying cars light enough to qualify for a lesser license, I doubt they'd pass (land vehicle) crash safety tests.
Seeing the 'skills' of my fellow drivers on the roads, there is no chance in hell that 95% of them could safely operate in a third dimension if they could takeoff and land wherever they wanted and fly however they wished, not to mention if there's only certain places they can do so (airfields, heliports, or maybe even your driveway (not currently allowed)). The FAA knows the carnage that would result if they turned everyone loose in the air--they'll make damn sure you can do it safely before they let you go--and we'll not even touch on the required medical exams.
Also, a terrorist would not need a valid pilot's license to steal someone else's flying car... and there are worse things that could be done than just flying into a high-rise.
No more than they'd need one to steal someone else's airplane. I'm assuming you're not a pilot (correct me if I'm wrong), but the majority of airfields in this country are quite small, compared to the big hubs most of us are used to flying into on 767s. Yeah, they've got fences around them, but the flightline's not controlled like at the big airports--everyone has to be able to drive up to their plane, load their stuff, walk around between the hangars to get food, fuel, rent aircraft, etc. And it's far easier to break into and hotwire than a car.
For all intents and purposes, the laws are the same--a flying car is just an airplane you can drive on a road. I can't imagine the FAA's going to say, "Oh, it's a flying car! You don't need a pilot's license, then--the ten-minute driving test you took when you were sixteen obviously qualifies you to operate an aircraft!"
Go to your local airport and find an FBO. Spend a few bucks and get a sectional chart--there's plenty of Prohibited and Restricted areas on there already that airplanes can't go into (especially around D.C.).
I just don't see this catching on--Joe Blow doesn't have the inclination (and likely not the skills) to put in his hours to get a pilot's license, won't want to preflight the thing for fifteen minutes every time he takes it out, or pay a few grand to replace the beacon light that just burned out (did I mention hardware certification is expensive?).
People who want the flexibility of a flying car can drive to the nearest small airport (they're all over the place), and get in their Cessna. Creating some kind of automated infrastructure (handling where vehicles can takeoff/land is only one problem) would be quite a task in itself, even if the common person was capable of piloting such a vehicle.
Generally known in military aviation as a Weight-on-Wheel (WOW) switch. The gear shouldn't come up (you'll also get an annoying warning klaxon, IIRC), and with the F-16's gear design, I too feel that the actuators would have trouble retracting the mains while loaded.
Also keep in mind that many other systems (fire control, navigation, radar) are inhibited while on the ground. One of the ex-USAF guys I work with had an amusing story--this is secondhand, so take it with a grain of salt. They needed to check something out on an aircraft, and it required WOW=false. So they lifted it off its wheels and started to power up the equipment, when they found that the radar had energized--keep in mind an airborne fire control radar is a bit stronger than a cop's radar gun.
By the time they shut it off, it had burned a hole a few feet in diameter through the (luckily unoccupied) hangar across the runway.
...to see how they track your speed and increase your premiums. After all, going 70 might be perfectly safe and legal on the rural interstate, but not in a school zone.
Another part of me thinks it would be nice to see an actual correlation between speed and accidents--since the police and insurance agencies have screamed for years that speed is what causes accidents. Even though most independent reports (which I can't remember to cite, but I'll mention them anyway:) put speed rather far down the list (driver inattention leads).
If they start seeing statistics that higher speeds do not lead to more accidents...ah, who am I kidding. Speeding tickets make too much money for the police and local governments, and the insurance companies (who buy them radar guns).
I'm not going to make any jokes about left handed people being sinister in case they ended up with all the mod points today.
Okay, it's been a few years since I was in Latin class, but...
As I recall, the word 'sinister' picked up its present connotation for just this reason. Supposedly (according to my teacher, anyway), since lefties are a statistical minority (what is it--8% of the populace now?) the Romans believed that there was something wrong with anyone who was left-handed. This was attributed to evil spirits or somesuch inhabiting the person. Hence the association of 'sinister' and 'evil'. Really!
Anyone else heard this, or was my Latin teacher full of it?
This actually reminds me of an orbital mechanics class I was in, years ago. The professor had just worked through an example on the board (a Hohmann Transfer to Mars, IIRC), and one of the other students asked if he could please work another one.
Deadpan, serious: "Okay, sure. This time, lets say we're sending this probe to...Uranus."
I'm thinking, Christ, I'm in a 400-level engineering course here--I can't laugh at something like that! I was doing okay as the prof. started in on the problem, when someone across the room burst out with a chuckle. At that point, myself (and most of the rest of the class) let go.
The prof. never seemed to figure out what he'd said--and I witnessed one of the two situations I can think of (the other being a proctologist's office) where you can actually say that line and be serious.
I don't think you understand the problem. The Earth moves around the sun at about 30 km/sec. Anything in Earth orbit is also moving at that speed relative to the sun. Push something toward the sun, and you just shift its orbit a bit. You need to cancel a large portion of that 30 km/sec velocity before the sun's gravity can actually pull it in.
Not necessarily. Yeah, according to the only reference I have on hand (Bate, Mueller, & White), Earth's heliocentric speed is 29.79 km/sec, and yes, that would have to be negated to drive directly into the sun. The heliocentric departure speed needed for a Hohman Transfer to Mercury, though, is down to 22.28 km/sec (followed, of course, by a braking maneuver to enter Mercury's orbit). I have no idea just how close you'd have to get this nuclear barge to the sun for it to burn up, but Mercury is a good reference point. So that's a delta-v of 7.51 km/sec (heliocentric).
Assuming we start in a geosynchronous orbit, that gives us a geocentric delta-v of about 5.6 km/sec (the calculations are left as an exercise for the reader:) ). That's really not all that bad. I don't have the time to do more math right now, but I'd say it's less energy than you'd need to get it to geosync in the first place.
You could also use gravity-assist trajectories, or run through the Interplanetary Superhigway system of transfer orbits for even less energy usage. Yeah, it will take a long time to get there, but who cares. Hell, we could just drive it far enough to get it established in a circular orbit that doesn't intersect with any of the other planets orbits or one of the Lagrange Points and let it sit there forever (though there was a ST:TNG episode with the bad results from doing something like this...) Not so terminal as flying it into the sun, but it (or however many barges they sent up) wouldn't do anything any harm that I could think of.
Really though, like the parent said earlier, the biggest reason they don't do this is because when one of the rockets breaks up on ascent (it will happen--sooner than later with todays rocket performance) we are screwed. Highly concentrated radioactive waste exploded a few miles up will make us think fondly of Chernobyl.
Maybe with a space elevator (if it ever becomes feasable), we could do this, but sending a great load of the stuff in minimal containers 22,500 miles up probably won't sit well with the people who don't want the stuff to travel in little bits 1,500 miles to Yucca Flats in a heavily armored cask.
On the subject of network saturation, how hard would it be to set up the system so that emergency services agencies got priority access? Say you dial *987#, then your desired number, the network intercepts the code (which could obviously be changed easily to something else), and gives your call a higher priority, dropping other calls if necessary. Either that, or in times of distress, the cell operators reserve a certain percentage of the available bandwidth for calls that start with the priority code. Then this code gets distributed to all the EMS, police, and fire agencies. Change it on a monthly basis, if desired--sure, there's opportunity for it to leak and be abused, but in the county I used to live, the keycodes to open the ambulance bay at the hospitals and the back-door, direct-line access to the EOC dispatchers (circumventing the 911 complaint-takers) were widely known (among other things) among all us emergency services types, and we never had any problems with those.
I seem to recall reading of something along these lines before, but I think it was fiction (Tom Clancy comes to mind). Anyone know if this is feasible, or has in fact been done somewhere? Seems like it would be handy--radios or not, cellphones are still heavily used by EMS et al (the radio gets congested, too), and those calls are likely more important that calling the power company to see when the lights will be back on, or even checking to see if your loved ones are okay (cold as that may sound).
It does that on a car because it's generally hooked to a circuit that gets disconnected when the starter is energized, so the starter has the most power possible.
Hook it to the right circuit, and it will still get power, though maybe not enough to keep the DCPS from dropping offline. Depends on its design, the kind of battery on the bike (usually small), starter draw and cranking time...
He might manage to keep it going, but those batteries _are_ pretty small...
To all the people saying that accuracy doesn't matter, or a guidance system could be created easily, let me throw in my impressions.
For a terror weapon, no--accuracy doesn't matter all that much. The V2 rockets Germany fired into Britain, for example, could generally hit pretty close to London. Firing an unguided rocket into an urban area, however, would be a little trickier. First off, any solid-fueled rocket I've seen of decent size leaves a visible trail of smoke (at least the larger ones; amateur rocket guys--correct me if I'm wrong), so it's fairly easy to trace it back to its launch point (not that the launcher would necessarily care).
Also, it would be pretty difficult to launch one of these from an urban area and not be noticed--you'll need a fairly large open field, especially if you're going for a longer range. Yeah, you could launch one straight up from your backyard, but it would come basically straight back down.
Finally, as to guidance--good luck. Even the old V2 was gyro-stabilized, and it did well to hit inside the city it was aimed at. GPS won't do you any good at all. Sure, it will give you a decent position and groundspeed, but it's updated at most at a 1-Hz rate.
To guide a missile, you need high-rate dynamic outputs (I'd say at least 100-Hz for a crude rocket), and good attitude (pitch/roll/yaw) outputs--GPS gives neither. You need an inertial navigation system, or at least an inertial attitude reference system, and those are very, very hard to make. I can think of three companies that sell these systems--two in the US, one in the UK, and I work for one of them (my opinions are my own, not my company's, etc.). They're on the State Department's Significant Military Technology List, which makes them hard to get, even if you've got the $50k-$200k to buy a nav-grade one.
Sure, if you had space to launch one from, and had the math/engineering background necessary to stabilize the rocket, compute its ballistic trajectory (you can do a decent numerical integration of this in Excel, even accounting for decreasing mass and thrust effects pretty easily and quickly, BTW), and had calm (or at least known, steady) winds...
Yeah, you could send a rocket with a small payload on a (pretty flat) trajectory for a few miles and probably manage to hit a (large) building or park-size area. But you're not going to shoot a rocket off at 80 from horizontal from 30 miles away and take out the president's car.
And actually making it explode...that's a whole new matter! Not my field, but I think constructing a fuzing device capable of detonating the warhead in a proximity fashion is beyond the scope of your 'common' terrorist. Likewise, if you wait for the impact to set it off, anything easily constructed to accomplish that would likely be destroyed before it managed to initiate the detonation. Putting in an unstable explosive won't work, either--it would explode on take off (we're talking, what--upwards of 30g's?). That leaves you commanded detonation, so you have to be close enough to see the rocket and detonate it before it smashed into something and broke, which is tricky at those speeds.
So basically, that leaves a short range rocket with a small payload that can't be too volatile, and is probably going to not blow up in the first place, or make a harmless fireball (and it's not heavy enough to make significant shrapnel). I'll admit, you could fill it with scary Chemical X, but I think the best you're going to accomplish is knocking out a window--like that kid who flew a Cessna into the Bank of America building in Tampa, taking out a few windows and half a cubicle.
I don't fear terrorist rockets--it would be a lot simpler to take the money and rent a truck, and fill it with any nasty number of things. Any idiot can do that.
But it's like with anything else. You want to stop people from doing things you don't want with computers? To the jail with them all. Don't want anyone to be able to make anything that might turn into a scary weapon? Throw all us engineers in there, too.
I am a pilot, and no disrespect to your rocket-scientist brethern, but the pilot of ANY craft should know about ANY anomalies in his craft before flight, and should have the option to say go, no-go.
Being an ersatz pilot, myself (30 hours in a Cessna must count for something...), I'll agree. I just wonder how many other 'minor' anomalies there are that could have destroyed the vehicle on that day--they're all basically prototype aircraft, after all.
I wonder how much of that is relayed to the pilot (or actually the Shuttle Commander, I suppose). Does he get a list of all the various things that could go wrong? It's not like he can do a walk around before the flight, after all.
At any rate, the Challenger incident, was far worse than Columbia in my mind-- NASA's performance was, at best, highly negligent for that one, but Thiokol's actions were criminal, in my mind.
If they knew this had a decent chance of occurring (hopefully after at least warning the crew--but some one at the very least should have told the launch operations crew about the blowby concern), they could have at least watched for it--after all, the flame jet is clearly visible from the time the SRBs ignite on several video feeds. Not like the fuzzy video of ice bouncing off the leading edge of Columbia's wing. When it was noticed that a leak had occurred, and was pointing in a direction that could endanger the vehicle, I'm relatively certain they could have put any number of abort scenarios into play. Manually jettison the SRBs (Range Safety can destruct them when they're clear), go to 110% on the SSMEs (main engines), and abort back to the Cape, transatlantic, or once-around (doubt they could have aborted to orbit from that altitude).
I definitely agree with keeping the pilot in the loop. In the civil (and military) aircraft arena, it works very well. Don't like the sound of an ATC vector? Let them know, and deviate if necessary. They want to know why the hell you're making a hard turn back to the airport instead of following their departure instructions? Let them wait while you do your job, and try to get the airplane stable after a cargo door just blew off and took an engine with it. I see no reason why the crew of the orbiter shouldn't have some input into what's going on.
But another, equally important (IMHO), lesson: if your engineers tell you that there's a problem, and chances are good it could make the space shuttle explode, fucking listen to them. That's why you're paying them, after all. Even if what they say is inconvenient in the financial arena, they're the ones who designed the systems. Do what they say.
As far as keeping the pilot informed, I'm not sure it would have helped in the Challenger case--he couldn't know the o-ring was leaking, after all. Of course, if one of the Thiokol engineers had managed to contact him in the few hours before launch and tell him the rockets might leak and burn a hole in his ship, I'm sure his ass would have stayed on the ground that day.
Columbia--yeah, NASA dropped the ball big time on that one. I haven't gotten around to reading the accident investigation on that one yet, but I'll be sadder yet if the engineers dropped the ball that badly. Management incompetence is bad enough, but if the systems designers et al. are that casual about such a situation...I just don't know what to think about that.
I'm mostly an airplane guy, but what I know of the shuttle program makes me say this--for damn sure, they could have tried harder. At least get the guys to look at the wing. No manuvering units on board? I'm sure if they told the crew there might be a big damn hole in the wing, they'd have found a way to look. Hell, pull some electrical cable from somewhere, tie some clothing articles together, and make a lifeline. Find a hole? Get Atlantis the hell on its way to the pad. Yes, rushing a launch like that would greatly increase the danger. But if you got all the shuttle pilots in a room, told them
Challenger had an o-ring problem that was wilfully ignored by engineers, and hidden from the pilots.
Sorry, but I've got to nitpick here, in defense of my fellow rocket scientists. The engineers at Morton Thiokol knew there was a problem with the o-rings on the SRBs. They'd seen these flame jets before when atmospheric temps were low--they'd just been lucky. Challenger's final flight happened on a cold day--you don't see ice in Florida, all that often. The engineers were worried, and they made their reservations known to Thiokol management.
Unfortunately, NASA was under pressure of its own to get the space program going (the space shuttle system has been behind task and overbudget since its inception), and they pressured Thiokol to sign off on the launch--it's usually the contractors that try to convince NASA that everything will be okay.
The engineers were increasingly concerned, and rushed to give a presentation to management urging them not to okay the launch until the temperatures had risen. There have been claims that they didn't present the data as well as they could, but they were under a terrible time-constraint to give their talk before the time for final launch approval came.
Say what you will of their presentation, but they made very clear that o-ring blowby was related to cold temperature, this was the coldest launch day ever, and that any o-ring blowby could RESULT IN THE LOSS OF THE VEHICLE.
Low temperatures were forcast for weeks, NASA pressured Thiokol management (who were trying to win some kind of contract for a systems upgrade) to okay the launch. Thiokol management told the engineers to leave the conference room--it was time to make a management decision, and the engineering manager needed to 'take off his engineer's hat, and put on his management hat' (best of my recollection). Can you imagine the sense of dread these guys must have had leaving the room?
The rest is history. Thiokol approved the launch, there was exhaust-gas blowby at one of the lower o-rings as had happened on several previous launches (again--this was a known problem at low temperatures), but this time, the flame jet didn't just fire off to the side--it impinged on the lower SRB-to-ET mount. 76 seconds into the flight the structural integrity of the mount was lost, followed by loss of the vehicle.
I'm going by memory here, but this is one of those things that most engineering colleges beat into you early on, as a lesson on the enormous weight of moral responsibility we must bear, and the consequences if we don't (even though the grunt engineers were not at fault for this disaster). Search the interweb for Boisjoly (one of the senior engineers). He went on a bit of a crusade after this, and lectures on engineering ethics now.
This thing will almost certainly be in low-earth orbit (LEO). That keeps it inside the Van Allen Belt, which do the majority of radiation shielding for us.
As I recall (I'm mostly an airplane guy, though I Am a Rocket Scientist), outside the Belt, radiation shielding isn't assured, anyway--it would make the craft far too heavy to launch. The trans-lunar Apollo missions, for example--if a solar flare came along at a bad time, those guys were toast. Sure, they could orient the craft to put as much of it between them and the sun as they could, but for a major solar flare, it wouldn't have been enough.
Sitting in the Belt itself is bad, too. Apollo guys were okay because they only spent a brief time crossing it, but they generally keep satellites out of that region because they wouldn't last long.
Keep the hotel close to Earth, and micrometeorites will be the biggest hazard.
Slashdot Mirror
All it takes is a well-aimed bucket of gravel in the right orbit to take out a space-based system. Launching buckets of gravel is pretty cheap, so unless the US system is 100% effective, this system will suffer from the same flaws as the anti-missile system - it's easy to overwhelm it with a lot of cheap countermeasures.
IIARS.
Technically, that's true--the math's pretty easy, so planning an orbital interception's not at all hard. Actually being able to carry it out is the hard part. You can't just put your bucket of gravel in the same orbit as the bird you want to destroy; everything in the same orbit is going the same speed. It has to--laws of physics and all. You really can't put it in a retrograde orbit, either, and smack it from the other side, as you'd have to negate the initial velocity from the earth's rotation, and that's not insignificant.
So you have to put your gravel in an orbit that will intercept the satellite's orbit. Assuming this bird is in low earth orbit (LEO), which is a safe bet, this is pretty easy to accomplish. Put your gravel in an elliptical orbit with the perigee matching the target bird's orbit, and make sure they'll get there at the same time.
That's the easy part, and it will get you close. The actual intercept, however, is where it gets hard. Space is big. Really big. All those satellites would be bouncing off each other all the time if it wasn't. A direct impact will require precise manuvering. That means a real orbital vehicle with manuvering thrusters, some kind of autonomous guidance system (inertial, startracker, etc.), and a terminal guidance package (probably radar). Even then, the velocities involved are very high--we're talking differences in kilometers per second, here--and a near-miss won't cut it. This is why the old kill-sats from the Cold War were designed with nuclear weapons on board. Close with a nuke is close enough.
Even with such a weapon, a successful intercept is not assured. We'd know something was coming well in advance. We've got some good reconnaisance satellites, so we'd see the thing sitting on a pad (orbital rockets are pretty big, and there's only so many places in the world that can launch them). Even if we managed to miss it, we'd see the launch, since watching for booster plumes (and nuclear explosions) is the primary purpose of more than one satellite sitting way up in GEO (geostationary orbit). Once we saw it coming up, US Space Command would know what kind of orbit it was in. If it looks dangerous or suspicious, they'd be ready for it. Just wait until the killsat is established on its final intercept course, and we kick our bird with some random delta-V. The other guy's intercept is now shot to hell, he likely won't have the fuel to try another one, and he's just pissed us off. We're out some manuvering fuel. Precious as on-orbit hydrazine is, it's better to expend it than have your whole satellite 'expended' for you.
NORAD and USSPACECOM are good. They played and plotted against the Soviets, and no one else these days plays near so good a game.
There's no such thing as 'cheap countermeasures' when you have to put them in orbit. There are precious few effective countermeasures, and they're anything but cheap.
--Ribald
A month down the road:
...
"Hey, guys--bad news. Turns out we were using the consumption rates in gallons of oxygen per minute, when we thought we were using liters! Heh, sorry about that."
"Guys? Hello?"
--Ribald
Here's some more, via FAS.
--Ribald
Except that you're more likely to have your gun pointed at you than you are to point it at someone else. I'd much rather take a 10% forward firing failure rate to reduce the chances of backfire by 100%.
I hear this statistic a lot, and it may actually be true. I don't think so, as the vast majority of defensive uses of a firearm result in a shot never being fired (that's the hypothesis, anyway)--consequently, the 'good' uses don't get reported.
Anyway, let's assume your statistic is, in fact, correct. I'd attribute this to people being stupid, so I don't have much sympathy. The only place for a gun, when it's not on your person, is in a safe--and a loaded gun in a safe is perfectly, um, safe, as it can't shoot anyone on its own. Perhaps at your bedside, while you sleep. If someone can break into your house, retrieve your loaded gun, and kill you with it, without you ever waking up, something else will probably kill you in your sleep eventually anyway. I dunno, a fire or escaped tiger or something.
Someone's breaking in? Rack the action on a shotgun, and I guarantee they'll haul ass out of there. A shotgun is more fearsome than an assault rifle, close-in, and criminals damn well know it. Anyone who doesn't run away from _any_ kind of drawn firearm can be assumed as intending to kill you. Keep your gun between him and your family, and call the police. If he makes off with the television, so be it. That's what insurance is for. If he comes toward you, warn him off--if he takes off, great. No one wants someone's death on their conscience, even if it's a scumbag. But if he keeps closing with you, he's going to fucking kill you.
This is not the time to worry whether the batteries in your gun are charged, or whether that papercut on your finger will false-negative the sensor. You want the simplest mechanism possible to throw those bits of lead at the other guy.
Anyone who can't be at least this responsible has no point owning _any_ kind of gun, smart or not. I see this causing people to respect the terrible destructive power contained in that small package even less than some idiots already do. This mechanism can fail both ways, just like manual safeties do. If you're nonchalantly waving the damn thing around when that happens, or leave it where your kids can get at it (it's 'smart', after all, so no accidents will happen, right?), it's going to punch a hole in something important.
I'm generally all for technology, but not here--education is the key.
--Ribald
Sorry, this might sound like a troll, it's not. Is your country really that f*ck*d up that people feel they aren't safe without weaponry? Your use of the word "necessary" seems to indicate that things are pretty screwed up where you are.
.45--entered service with the US military in 1911, and was used until they standardized on 9mms with NATO in 1985. It's been proven reliable, and you can completely disassemble it using no tools. THAT is what a defensive weapon should be. A solid chunk of stainless steel--not something you have to worry about shock damaging the electronics. Not when your life is on the line. It would be better to just not let the bad guy get ahold of your gun. (Seriously--there's courses on weapon retention for just this reason).
Surely this is an over exaggeration isn't it?
Don't I wish. The courts have long upheld that the police have no legal responsibility to protect individual persons--rather, their job is to attempt to enforce the laws on the books and just generally 'show the flag'.
Back when I was still in school, I was with a volunteer rescue squad. Emergency medicine, vehicle extrication, stuff like that. I spent a year living in one of the stations (no rent, just keep the truck in service). I noticed some holes in the front wall right after I moved in. Inquiries revealed that they'd come from a rifle shot from a passing car (it was a cheap modular building, so it went out the back wall, too). This was in a pretty rural suburb, without much in the way of crime.
The three people inside called the police and hid, hoping no one was going to come kicking their door in before they got there--many people were under the mistaken impression we had some cache of narcotics stored there for medical use (we let the ambulances carry those for us), so we had to worry about junkies breaking into our vehicles and buildings.
Luckily, nothing like that happened, as a cop car didn't roll up for twenty minutes. He'd been dispatched as 'investigate shots fired at an abandoned building'--a non-priority response. Had it been an actual robbery/home-invasion...
I applied for a firearm carry permit the next week. Yes, it can be that screwed up over here (I'm speaking of the US). I've never drawn a gun in anger, and I hope to God I never have to. But just reading the newspapers makes me glad I've got the ability to meet force with force--better to have it and never need to use it...
So I'll echo the OP--this is a bad idea. I prefer my
--Ribald
Licensed to carry in 30 states
Remember the Netscape fishtank?
I remember how cool I thought that was, back when I first started using Netscape (v. 2.02, I believe). Just a static image of the fishtank in their lobby that would be updated every 60 sec. or so, and not much to get excited about these days.
But it was a big change from what Gopher offered.
--Ribald
(I miss Gopher, too.)
Diesel engines are pretty constantly turning low RPMs, and the fan systems are designed for that. I have yet to see a system of electric fans that will work as well as the one large belt-driven fan mounted on my truck. The thing sounds more like a propeller.
Electrics are great for cars and smaller trucks, but when you really start up the displacement ladder...
--Ribald
My apologies--I'm used to dealing with my less mechanically-inclined friends. I would be interested in the vehicle type, as I've not heard of such a system. Then again, my power steering pump drives my brake assist, so I'm sure it's possible.
Electric fans are great for smaller engines. Most of these are mounted transversely these days, so that's about the only kind of fan available. Large engines in trucks, though, are a bit harder to fit with an electric fan. Towing vehicles, especially. I've known people to try using the largest available as replacements, and most have experienced overheating. For sheer airflow, it's hard to beat a large engine-driven (through a clutch) fan.
--Ribald
You think that's scary? There are actually cooling fans that run off the power steering pump. Talk about bizarre. If your power steering fails, your car overheats.
I don't think that's quite how it works, at least on any vehicle I'm familiar with. There are one or more belts on the front of most engines. At least one is connected to the crankshaft, and power is distributed from there to the pulleys that run the airconditioning, alternator, power steering, water pump, fan...
They're connected, yes, but the fan is driven off the crank, just like the PS pump.
--Ribald
If you shut off the engine, you will lose your power steering, as it's powered by an engine-driven pump. Since all you need to do is turn a few degrees to the side to guide it to the shoulder, though, the manual fallover works just fine.
Most power brakes are run by engine vacuum (some, like my truck, are a hydroboost system off the power steering pump). There's generally (actually, I think it's required by law) an accumulator that will store engine vacuum. You get at least two or three full-pressure applications before the vacuum is exhausted, and then it's fallover to the unassisted hydraulic brakes--you can still stop, it'll just take longer.
My truck weighs in excess of 7000 pounds (3175 kg), and I can easily control it with the engine off (one of the first things I did after buying it was get it up to speed in a parking lot and shut it off, to see how it handled).
Just shut off the engine, put the transmission in neutral, keep steady pressure on the brakes (pump them, and you're out of power assist in short order), steer to the side of the road. Just don't turn the key to lock, or whatever causes the steering column to lock in place--there should be an interlock requiring you to push a button or press in the key to do that, anyway.
This should be a non-event.
Broken steering shaft, or an old straight-air tractor-trailer with an air system failure--there's something to be excited about.
--Ribald
Traffic in the sky won't multiply by 10,000x, because this will never catch on. There aren't that many people willing to go through the expense and difficulty of learning how to fly (even if it's much more simplified than common light airplanes) and getting licensed.
As far as blending in to traffic, you can do that with a rental truck, too--and I assure you, it will hold far, far more explosives than any light airplane or flying car. You can't pack enough stuff in a small aircraft to make a dent in anything important.
And by the way, you can't necessarily track any single vehicle in the sky now. Most civil radar installations will pick up an aircraft, but you only get azimuth and range, with no altitude info or identification. That's what the transponders in the airplanes are for (they reply when interrogated with the altitude as reported by your altimeter and with the 'squawk' code you've entered--1200, unless they give you a new one), and you can turn them off. Don't want them to know who you are? Stay off the radio, turn off the xpdr, fly low--reminds me of all those Microprose sims I played back in the '80s, but military surveillance and fire control radars are a bit nicer than the ASR and ARSR sets the FAA operates--they generally don't have to deal with aircraft that don't want to be found, and there's plenty of airspace left that's uncontrolled.
Really, though--it's like worrying about people on bicycles or motorcycles being able to blow up a building because they can get around the crash barricades set up to keep trucks out. They can get in, sure, but not carrying enough of anything to do any real damage.
--Ty
That'll teach me to use preview next time:
And it's far easier to break into and hotwire than a car.
What I'm trying to say is that it's child's play to steal a light aircraft. Many of these old Cessnas are 40 years old--yeah, the doors lock, and there's an ignition key, but either one is easier to defeat than those on my truck (which I've had to break into a few times, with nothing more than a flat strip of aluminum, notched at the end).
People are sparse at some of these fields, and many airplanes are not in hangars, but just tied up in the grass, or an incomplete strip hangar that provides only a roof. Access is easy, getting in the airplane is easy, and unless someone working at the FBO (Fixed Base Operator--they sell fuel and stuff) sees you breaking in or notices that someone different is flying that plane today, you can just fly away with no one the wiser.
Reference that kid who stole an airplane from the St. Pete/Clearwater Airport about 2.5 years ago. Hell, they knew he wasn't supposed to be flying the airplane, and the Coast Guard (also based there) managed to get a helicopter after him while he was rolling down the runway, but he still managed to fly to downtown Tampa (over MacDill AFB, home of US SOCOM and CENTCOM) and crash into the Bank of America Building. Luckily for them, a Cessna 172 is pretty light, and he managed to take out a window and knock down a cubicle (plane didn't even make it all the way inside).
--Ribald
You don't need a full pilot's license for some recreational aircraft, and you likely won't need one for fying cars either.
Correct--but you do need a pilot's license. It's been a few years since I looked into it, but used to be the Recreational Pilot Certificate was the lowest-grade pilot's certificate one could obtain in the US (Private Pilot being the mark most people aim for initially). There are restrictions on aircraft size (hint--it's small), carrying passengers, airports that can be used, more stringent weather minimums, etc. They've issued few of these to date, as the requirements aren't much less than for a Private cert, so why bother?
There's been a motion for years to create an easier-still certification, and this may have recently come to fruition. The restrictions here were pretty severe--going from memory, there's only a handful of aircraft small enough to qualify, you only get one passenger, can't fly at night, etc. (if anyone knows better, please chime in).
But when you consider all that, keep in mind that you still need something like 20 hours of instruction (minimum) and passing several exams (written and practical) before you can fly. This ain't a driver's license--it requires no small amount of skill and training to fly, let alone land, one of these. Plus, these 'recreational' aircraft are tiny. A Cessna 150/152, for example--long a mainstay of primary flight training--has enough room for two people up front, generally with shoulders touching the side windows and each other, and a small bit of room behind the seat for a bag or two. A Mazda Miata has more room inside, and weighs quite a bit more, as I recall. If they made these flying cars light enough to qualify for a lesser license, I doubt they'd pass (land vehicle) crash safety tests.
Seeing the 'skills' of my fellow drivers on the roads, there is no chance in hell that 95% of them could safely operate in a third dimension if they could takeoff and land wherever they wanted and fly however they wished, not to mention if there's only certain places they can do so (airfields, heliports, or maybe even your driveway (not currently allowed)). The FAA knows the carnage that would result if they turned everyone loose in the air--they'll make damn sure you can do it safely before they let you go--and we'll not even touch on the required medical exams.
Also, a terrorist would not need a valid pilot's license to steal someone else's flying car... and there are worse things that could be done than just flying into a high-rise.
No more than they'd need one to steal someone else's airplane. I'm assuming you're not a pilot (correct me if I'm wrong), but the majority of airfields in this country are quite small, compared to the big hubs most of us are used to flying into on 767s. Yeah, they've got fences around them, but the flightline's not controlled like at the big airports--everyone has to be able to drive up to their plane, load their stuff, walk around between the hangars to get food, fuel, rent aircraft, etc. And it's far easier to break into and hotwire than a car.
--Ribald
They're called 'airplanes'.
For all intents and purposes, the laws are the same--a flying car is just an airplane you can drive on a road. I can't imagine the FAA's going to say, "Oh, it's a flying car! You don't need a pilot's license, then--the ten-minute driving test you took when you were sixteen obviously qualifies you to operate an aircraft!"
Go to your local airport and find an FBO. Spend a few bucks and get a sectional chart--there's plenty of Prohibited and Restricted areas on there already that airplanes can't go into (especially around D.C.).
I just don't see this catching on--Joe Blow doesn't have the inclination (and likely not the skills) to put in his hours to get a pilot's license, won't want to preflight the thing for fifteen minutes every time he takes it out, or pay a few grand to replace the beacon light that just burned out (did I mention hardware certification is expensive?).
People who want the flexibility of a flying car can drive to the nearest small airport (they're all over the place), and get in their Cessna. Creating some kind of automated infrastructure (handling where vehicles can takeoff/land is only one problem) would be quite a task in itself, even if the common person was capable of piloting such a vehicle.
--Ribald
Generally known in military aviation as a Weight-on-Wheel (WOW) switch. The gear shouldn't come up (you'll also get an annoying warning klaxon, IIRC), and with the F-16's gear design, I too feel that the actuators would have trouble retracting the mains while loaded.
Also keep in mind that many other systems (fire control, navigation, radar) are inhibited while on the ground. One of the ex-USAF guys I work with had an amusing story--this is secondhand, so take it with a grain of salt. They needed to check something out on an aircraft, and it required WOW=false. So they lifted it off its wheels and started to power up the equipment, when they found that the radar had energized--keep in mind an airborne fire control radar is a bit stronger than a cop's radar gun.
By the time they shut it off, it had burned a hole a few feet in diameter through the (luckily unoccupied) hangar across the runway.
--Ribald
...to see how they track your speed and increase your premiums. After all, going 70 might be perfectly safe and legal on the rural interstate, but not in a school zone.
:) put speed rather far down the list (driver inattention leads).
Another part of me thinks it would be nice to see an actual correlation between speed and accidents--since the police and insurance agencies have screamed for years that speed is what causes accidents. Even though most independent reports (which I can't remember to cite, but I'll mention them anyway
If they start seeing statistics that higher speeds do not lead to more accidents...ah, who am I kidding. Speeding tickets make too much money for the police and local governments, and the insurance companies (who buy them radar guns).
--Ribald
I'm not going to make any jokes about left handed people being sinister in case they ended up with all the mod points today.
Okay, it's been a few years since I was in Latin class, but...
As I recall, the word 'sinister' picked up its present connotation for just this reason. Supposedly (according to my teacher, anyway), since lefties are a statistical minority (what is it--8% of the populace now?) the Romans believed that there was something wrong with anyone who was left-handed. This was attributed to evil spirits or somesuch inhabiting the person. Hence the association of 'sinister' and 'evil'. Really!
Anyone else heard this, or was my Latin teacher full of it?
--Ribald
This actually reminds me of an orbital mechanics class I was in, years ago. The professor had just worked through an example on the board (a Hohmann Transfer to Mars, IIRC), and one of the other students asked if he could please work another one.
Deadpan, serious: "Okay, sure. This time, lets say we're sending this probe to...Uranus."
I'm thinking, Christ, I'm in a 400-level engineering course here--I can't laugh at something like that! I was doing okay as the prof. started in on the problem, when someone across the room burst out with a chuckle. At that point, myself (and most of the rest of the class) let go.
The prof. never seemed to figure out what he'd said--and I witnessed one of the two situations I can think of (the other being a proctologist's office) where you can actually say that line and be serious.
--Ribald
I don't think you understand the problem. The Earth moves around the sun at about 30 km/sec. Anything in Earth orbit is also moving at that speed relative to the sun. Push something toward the sun, and you just shift its orbit a bit. You need to cancel a large portion of that 30 km/sec velocity before the sun's gravity can actually pull it in.
:) ). That's really not all that bad. I don't have the time to do more math right now, but I'd say it's less energy than you'd need to get it to geosync in the first place.
Not necessarily. Yeah, according to the only reference I have on hand (Bate, Mueller, & White), Earth's heliocentric speed is 29.79 km/sec, and yes, that would have to be negated to drive directly into the sun. The heliocentric departure speed needed for a Hohman Transfer to Mercury, though, is down to 22.28 km/sec (followed, of course, by a braking maneuver to enter Mercury's orbit). I have no idea just how close you'd have to get this nuclear barge to the sun for it to burn up, but Mercury is a good reference point. So that's a delta-v of 7.51 km/sec (heliocentric).
Assuming we start in a geosynchronous orbit, that gives us a geocentric delta-v of about 5.6 km/sec (the calculations are left as an exercise for the reader
You could also use gravity-assist trajectories, or run through the Interplanetary Superhigway system of transfer orbits for even less energy usage. Yeah, it will take a long time to get there, but who cares. Hell, we could just drive it far enough to get it established in a circular orbit that doesn't intersect with any of the other planets orbits or one of the Lagrange Points and let it sit there forever (though there was a ST:TNG episode with the bad results from doing something like this...) Not so terminal as flying it into the sun, but it (or however many barges they sent up) wouldn't do anything any harm that I could think of.
Really though, like the parent said earlier, the biggest reason they don't do this is because when one of the rockets breaks up on ascent (it will happen--sooner than later with todays rocket performance) we are screwed. Highly concentrated radioactive waste exploded a few miles up will make us think fondly of Chernobyl.
Maybe with a space elevator (if it ever becomes feasable), we could do this, but sending a great load of the stuff in minimal containers 22,500 miles up probably won't sit well with the people who don't want the stuff to travel in little bits 1,500 miles to Yucca Flats in a heavily armored cask.
--Ribald
(IIARS)
On the subject of network saturation, how hard would it be to set up the system so that emergency services agencies got priority access? Say you dial *987#, then your desired number, the network intercepts the code (which could obviously be changed easily to something else), and gives your call a higher priority, dropping other calls if necessary. Either that, or in times of distress, the cell operators reserve a certain percentage of the available bandwidth for calls that start with the priority code. Then this code gets distributed to all the EMS, police, and fire agencies. Change it on a monthly basis, if desired--sure, there's opportunity for it to leak and be abused, but in the county I used to live, the keycodes to open the ambulance bay at the hospitals and the back-door, direct-line access to the EOC dispatchers (circumventing the 911 complaint-takers) were widely known (among other things) among all us emergency services types, and we never had any problems with those.
I seem to recall reading of something along these lines before, but I think it was fiction (Tom Clancy comes to mind). Anyone know if this is feasible, or has in fact been done somewhere? Seems like it would be handy--radios or not, cellphones are still heavily used by EMS et al (the radio gets congested, too), and those calls are likely more important that calling the power company to see when the lights will be back on, or even checking to see if your loved ones are okay (cold as that may sound).
--Ribald
It does that on a car because it's generally hooked to a circuit that gets disconnected when the starter is energized, so the starter has the most power possible.
Hook it to the right circuit, and it will still get power, though maybe not enough to keep the DCPS from dropping offline. Depends on its design, the kind of battery on the bike (usually small), starter draw and cranking time...
He might manage to keep it going, but those batteries _are_ pretty small...
--Ribald
To all the people saying that accuracy doesn't matter, or a guidance system could be created easily, let me throw in my impressions.
For a terror weapon, no--accuracy doesn't matter all that much. The V2 rockets Germany fired into Britain, for example, could generally hit pretty close to London. Firing an unguided rocket into an urban area, however, would be a little trickier. First off, any solid-fueled rocket I've seen of decent size leaves a visible trail of smoke (at least the larger ones; amateur rocket guys--correct me if I'm wrong), so it's fairly easy to trace it back to its launch point (not that the launcher would necessarily care).
Also, it would be pretty difficult to launch one of these from an urban area and not be noticed--you'll need a fairly large open field, especially if you're going for a longer range. Yeah, you could launch one straight up from your backyard, but it would come basically straight back down.
Finally, as to guidance--good luck. Even the old V2 was gyro-stabilized, and it did well to hit inside the city it was aimed at. GPS won't do you any good at all. Sure, it will give you a decent position and groundspeed, but it's updated at most at a 1-Hz rate.
To guide a missile, you need high-rate dynamic outputs (I'd say at least 100-Hz for a crude rocket), and good attitude (pitch/roll/yaw) outputs--GPS gives neither. You need an inertial navigation system, or at least an inertial attitude reference system, and those are very, very hard to make. I can think of three companies that sell these systems--two in the US, one in the UK, and I work for one of them (my opinions are my own, not my company's, etc.). They're on the State Department's Significant Military Technology List, which makes them hard to get, even if you've got the $50k-$200k to buy a nav-grade one.
Sure, if you had space to launch one from, and had the math/engineering background necessary to stabilize the rocket, compute its ballistic trajectory (you can do a decent numerical integration of this in Excel, even accounting for decreasing mass and thrust effects pretty easily and quickly, BTW), and had calm (or at least known, steady) winds...
Yeah, you could send a rocket with a small payload on a (pretty flat) trajectory for a few miles and probably manage to hit a (large) building or park-size area. But you're not going to shoot a rocket off at 80 from horizontal from 30 miles away and take out the president's car.
And actually making it explode...that's a whole new matter! Not my field, but I think constructing a fuzing device capable of detonating the warhead in a proximity fashion is beyond the scope of your 'common' terrorist. Likewise, if you wait for the impact to set it off, anything easily constructed to accomplish that would likely be destroyed before it managed to initiate the detonation. Putting in an unstable explosive won't work, either--it would explode on take off (we're talking, what--upwards of 30g's?). That leaves you commanded detonation, so you have to be close enough to see the rocket and detonate it before it smashed into something and broke, which is tricky at those speeds.
So basically, that leaves a short range rocket with a small payload that can't be too volatile, and is probably going to not blow up in the first place, or make a harmless fireball (and it's not heavy enough to make significant shrapnel). I'll admit, you could fill it with scary Chemical X, but I think the best you're going to accomplish is knocking out a window--like that kid who flew a Cessna into the Bank of America building in Tampa, taking out a few windows and half a cubicle.
I don't fear terrorist rockets--it would be a lot simpler to take the money and rent a truck, and fill it with any nasty number of things. Any idiot can do that.
But it's like with anything else. You want to stop people from doing things you don't want with computers? To the jail with them all. Don't want anyone to be able to make anything that might turn into a scary weapon? Throw all us engineers in there, too.
--Ribald
I am a pilot, and no disrespect to your rocket-scientist brethern, but the pilot of ANY craft should know about ANY anomalies in his craft before flight, and should have the option to say go, no-go.
Being an ersatz pilot, myself (30 hours in a Cessna must count for something...), I'll agree. I just wonder how many other 'minor' anomalies there are that could have destroyed the vehicle on that day--they're all basically prototype aircraft, after all.
I wonder how much of that is relayed to the pilot (or actually the Shuttle Commander, I suppose). Does he get a list of all the various things that could go wrong? It's not like he can do a walk around before the flight, after all.
At any rate, the Challenger incident, was far worse than Columbia in my mind-- NASA's performance was, at best, highly negligent for that one, but Thiokol's actions were criminal, in my mind.
If they knew this had a decent chance of occurring (hopefully after at least warning the crew--but some one at the very least should have told the launch operations crew about the blowby concern), they could have at least watched for it--after all, the flame jet is clearly visible from the time the SRBs ignite on several video feeds. Not like the fuzzy video of ice bouncing off the leading edge of Columbia's wing. When it was noticed that a leak had occurred, and was pointing in a direction that could endanger the vehicle, I'm relatively certain they could have put any number of abort scenarios into play. Manually jettison the SRBs (Range Safety can destruct them when they're clear), go to 110% on the SSMEs (main engines), and abort back to the Cape, transatlantic, or once-around (doubt they could have aborted to orbit from that altitude).
I definitely agree with keeping the pilot in the loop. In the civil (and military) aircraft arena, it works very well. Don't like the sound of an ATC vector? Let them know, and deviate if necessary. They want to know why the hell you're making a hard turn back to the airport instead of following their departure instructions? Let them wait while you do your job, and try to get the airplane stable after a cargo door just blew off and took an engine with it. I see no reason why the crew of the orbiter shouldn't have some input into what's going on.
But another, equally important (IMHO), lesson: if your engineers tell you that there's a problem, and chances are good it could make the space shuttle explode, fucking listen to them. That's why you're paying them, after all. Even if what they say is inconvenient in the financial arena, they're the ones who designed the systems. Do what they say.
As far as keeping the pilot informed, I'm not sure it would have helped in the Challenger case--he couldn't know the o-ring was leaking, after all. Of course, if one of the Thiokol engineers had managed to contact him in the few hours before launch and tell him the rockets might leak and burn a hole in his ship, I'm sure his ass would have stayed on the ground that day.
Columbia--yeah, NASA dropped the ball big time on that one. I haven't gotten around to reading the accident investigation on that one yet, but I'll be sadder yet if the engineers dropped the ball that badly. Management incompetence is bad enough, but if the systems designers et al. are that casual about such a situation...I just don't know what to think about that.
I'm mostly an airplane guy, but what I know of the shuttle program makes me say this--for damn sure, they could have tried harder. At least get the guys to look at the wing. No manuvering units on board? I'm sure if they told the crew there might be a big damn hole in the wing, they'd have found a way to look. Hell, pull some electrical cable from somewhere, tie some clothing articles together, and make a lifeline. Find a hole? Get Atlantis the hell on its way to the pad. Yes, rushing a launch like that would greatly increase the danger. But if you got all the shuttle pilots in a room, told them
Challenger had an o-ring problem that was wilfully ignored by engineers, and hidden from the pilots.
Sorry, but I've got to nitpick here, in defense of my fellow rocket scientists. The engineers at Morton Thiokol knew there was a problem with the o-rings on the SRBs. They'd seen these flame jets before when atmospheric temps were low--they'd just been lucky. Challenger's final flight happened on a cold day--you don't see ice in Florida, all that often. The engineers were worried, and they made their reservations known to Thiokol management.
Unfortunately, NASA was under pressure of its own to get the space program going (the space shuttle system has been behind task and overbudget since its inception), and they pressured Thiokol to sign off on the launch--it's usually the contractors that try to convince NASA that everything will be okay.
The engineers were increasingly concerned, and rushed to give a presentation to management urging them not to okay the launch until the temperatures had risen. There have been claims that they didn't present the data as well as they could, but they were under a terrible time-constraint to give their talk before the time for final launch approval came.
Say what you will of their presentation, but they made very clear that o-ring blowby was related to cold temperature, this was the coldest launch day ever, and that any o-ring blowby could RESULT IN THE LOSS OF THE VEHICLE.
Low temperatures were forcast for weeks, NASA pressured Thiokol management (who were trying to win some kind of contract for a systems upgrade) to okay the launch. Thiokol management told the engineers to leave the conference room--it was time to make a management decision, and the engineering manager needed to 'take off his engineer's hat, and put on his management hat' (best of my recollection). Can you imagine the sense of dread these guys must have had leaving the room?
The rest is history. Thiokol approved the launch, there was exhaust-gas blowby at one of the lower o-rings as had happened on several previous launches (again--this was a known problem at low temperatures), but this time, the flame jet didn't just fire off to the side--it impinged on the lower SRB-to-ET mount. 76 seconds into the flight the structural integrity of the mount was lost, followed by loss of the vehicle.
I'm going by memory here, but this is one of those things that most engineering colleges beat into you early on, as a lesson on the enormous weight of moral responsibility we must bear, and the consequences if we don't (even though the grunt engineers were not at fault for this disaster). Search the interweb for Boisjoly (one of the senior engineers). He went on a bit of a crusade after this, and lectures on engineering ethics now.
Those bastards running Thiokol should be in jail.
--Ribald
This thing will almost certainly be in low-earth orbit (LEO). That keeps it inside the Van Allen Belt, which do the majority of radiation shielding for us.
As I recall (I'm mostly an airplane guy, though I Am a Rocket Scientist), outside the Belt, radiation shielding isn't assured, anyway--it would make the craft far too heavy to launch. The trans-lunar Apollo missions, for example--if a solar flare came along at a bad time, those guys were toast. Sure, they could orient the craft to put as much of it between them and the sun as they could, but for a major solar flare, it wouldn't have been enough.
Sitting in the Belt itself is bad, too. Apollo guys were okay because they only spent a brief time crossing it, but they generally keep satellites out of that region because they wouldn't last long.
Keep the hotel close to Earth, and micrometeorites will be the biggest hazard.
--Riblald