You must be thinking of a different ride. In Superman: The Escape, you're first accelerated horizontally along a straight track by a linear induction motor. The track then pitches straight up 90 degrees. You come to a stop at the top of the vertical section and fall back in reverse to the starting point. From the time you finish the pitch-up until you fall back to it, you're weightless. That's about 6 or 6.5 seconds of zero-gee, depending on your speed after pitch-up.
I can't think of a better design for an amusement ride designed to produce weightlessness. It's my favorite. I usually like to make my camera float and dance around on the end of its carrying strap. It really is a pretty good zero-gee, unlike some rides where you're actively pulled down faster than free-fall (e.g., Disney's "Tower of Terror" and "Maliboomer").
Why didn't I do it years ago? Simple. There was no point. I can think of many other ways I'd rather spend $10-20M if I had it. Oh, and by the way I do help design, build and operate stuff that goes into space. I do it both professionally and as a hobby.
...until a couple of months ago nobody in the private sector could even go suborbital...
...the absolute beginning for commercial exploration...
Really? What about Boeing, Lockheed-Martin, Orbital Sciences, Arianespace, SeaLaunch and a couple of Russian and Chinese companies whose names I can't think of at the moment? They've been providing commercial space launch services for decades now. Or don't they count because they just launch boring unmanned satellites that lots of people on the ground actually find useful?
Before everybody gets swept up in all the hype and euphoria, remember that altitude -- even 100 km -- is easy. Staying in space is the hard part. That takes kinetic energy, a lot of it. The potential energy at 100km is less than 4% of the total kinetic + potential energy it takes to stay in a 100km orbit, which is actually much too low to be stable.
SpaceShipOne is for quickie suborbital jaunts only. Rutan is still far, far away from reaching orbit. Your $100K or whatever would buy you just 3.5 minutes of weightlessness at about $475/second. If you're willing to give up the view (SpaceShipOne's windows aren't that great anyway), you can experience weightlessness a lot more cheaply on an airplane ($3K for several 20-second periods) or for 6.5 seconds on the "Superman: The Escape" ride at Six Flags. A full-price Six Flags ticket is $47, so that's only $7.20/second even if you only ride once!
Over the years I've seen many space entrepreneurs pop up, complain about how evil and incompetent and bureaucratic NASA is, and make lots of noise about how they could do far better if the government would just "get out of their way", whatever that means. After a few years (or less), they run out of money and disappear. Some reappear in other startups to repeat the cycle.
So I am always very skeptical whenever the major theme of some space-related startup seems to revolve more around bashing NASA than actually building a good product. It's not that NASA is terribly wonderful -- it has many problems -- but the simple truth is that the business of space flight is a lot harder than many naive entrepreneurs (and their lay cheerleaders) think it is.
Rutan is, by far, the most "real" space entrepreneur to come along in a long time. He clearly earned his X-Prize, and I congratulate him for it. But I sure do wish he'd ease off on his NASA-bashing and concede that space has always had plenty of room for both business and government, especially in cooperative projects. NASA may be a government institution, but it has a lot of real flesh-and-blood people who want to promote space exploration and development just as he does, and many of them are actually quite bright. Now that Rutan has finally reached the point NASA first passed in the late 1950s, he may discover that the next steps aren't quite as easy as he thought.
The "private enterprise in space" mantra is practically a religion with some people, and like most religions it's based more on wishful thinking than reality.
There's really no such thing as a "privately financed" space venture, including Rutan's. He, like everyone else in that business, has the benefit of 50+ years of experience and technology courtesy of various military and government space programs. At least one can't accuse Rutan of being a purist; he certainly doesn't shrink from using government services when they're available. Flights of SpaceShipOne are covered live on NASA TV, and an Air Force radar determined the altitude of each shot.
I find it most interesting that you would mention the Iridium/Globalstar/ICO failure, one of the most spectacular examples ever of a market flameout caused by ridiculously optimistic marketing estimates for a premium-priced service, and then maintain that there is nonetheless a big untapped market for $100,000 plane tickets from LAX to Sydney. The best way for really busy people to save time traveling is -- and remains -- telecommunications. And it works for the rest of us, not just the extremely wealthy.
Yes, I'm aware of the surveys that claim a lot of people would be willing to spend big bucks for a joyride into space. But you must know how those marketing surveys are conducted. There's a very big difference between casually saying "sure, why not" to the guy on the phone, and actually signing the check. Not to mention those liability waivers...
Gasoline engines and rocket engines both burn fuels in heat engines as a means of transportation. That's about where their similarities ends. The amounts of fuel required, the powers and power densities, and the safety considerations aren't even remotely comparable. So the success of the internal combustion engine in personal ground transportation has no bearing on the success of "personal" space flight.
I have no problems with properly informed people risking their own lives (but not others' lives). It's a free country, or it's supposed to be. That means I also have the right to speak out when I see people being misled or sold a bill of goods. Especially when I think they're being misled about potential risks to their safety.
Personally, I think the only approach that will provide the many orders-of-magnitude reduction in cost necessary to colonize space on a large scale will be the space elevator. And the materials and engineering challenges are so daunting that there's virtually no chance of it occurring in my lifetime.
Okay, let me amend my statement to read "radically cheaper new ideas, or opportunities for radically reducing the costs of existing technologies". And "cost" includes safety and liability aspects. Phrased this way, I still stand by it. Maybe I've missed something, but I see no new ideas on the horizon that promise to get stuff into space orders of magnitude more cheaply than before, nor do I see any opportunities to cost-reduce existing technologies by those same necessary orders of magnitude. Especially when you need that extra margin of safety to fly passengers rather than expendable machines.
Safe, reliable and effective chemical rockets are inherently expensive. Based on what I've seen so far, Rutan has kept his costs down by substantially lowering his goals (quickie suborbital jaunts vs orbit) and by cutting substantial corners on safety and reliability. I actually cringed when I heard that he's going for the second prize flight today, because I don't think he has a clue why his last flight executed those "unscripted roll maneuvers". The last two SpaceShipOne flights both had some major unexpected problem that came close to disaster, and it's only by sheer luck that he hasn't yet lost a plane and its pilot. Unfortunately, he wants that X-Prize so badly that I think it has clouded his judgment.
I'm reminded of the many early Soviet "firsts" in manned space exploration that we later learned happened not because Soviet space technology was better than ours, but because they were much more willing to risk their pilots on PR stunts than we were. We saw how far that got them later on.
I sincerely hope Rutan succeeds tomorrow. But I fear his luck can't hold out forever.
Actually, the space launch companies get much of their income from the purely commercial communications satellite business. Sure, they also sell launchers and launch services to the government, especially the military and NASA, but so what? The government is a really big buyer of all sorts of goods and services, only some of which are rockets. Or do you mean to say that because Rutan's craft is purpose-built for quickie joyrides for rich entrepreneurs and is totally useless for practical applications like launching commercial spacecraft into orbit, he's somehow more "pure free enterprise" than all the other space launch companies that have real businesses as customers?
Every space launch company has an incentive to innovate, cut costs and improve reliability. They compete with each other even (especially) when the government is the customer. Sure, there's room for more competition, but that's not the same as saying there's none.
I'm always amused when somebody crows about how much money will be saved by a new launcher that has never flown versus one that's been flying for a decade or more. It's as if the person has never heard of cost overruns and engineering setbacks, not to mention lowballing in the marketing department. I think I'd prefer to wait until a new launcher has a proven track record before I made those kinds of claims.
This is a total non-problem. California was so interested in getting electric cars on the road that not only did they not care that I didn't pay any gas taxes, they gave me a substantial subsidy! (Actually, they gave the subsidy to GM, who claimed that it was the only way they leased the car to me for the price they did.)
When electric cars become widespread and no longer require subsidies, we can easily solve the problem of raising money to build and maintain roads. You already have to tell your insurance company how much you drive every year. So give the state the same information when you renew your registration and they'll base the renewal fee on it.
Speaking as a former EV1 driver (I can't say "owner" for the reasons you give so eloquently), I can certainly agree with what you said about the outrageousness of the car manufacturers.
How exactly is hydrogen power advancing? Automotive fuel cells are getting smaller and cheaper, but they don't seem to be getting significantly more efficient. About 50% from hydrogen gas to electricity seems to be par for the course. Combine that with the 70% efficiency of industrial-scale electrolyzers, and we're already down to a 35% end-to-end energy transmission efficiency even if the transmission and distribution infrastructure is 100% efficient and cost free. That compares to an end-to-end energy efficiency fo about 95% for the existing power grid. And I thought part of the point of all this was to help save energy and reduce global warming?
And what about the hydrogen storage problem?
The grid already does go just about everywhere it needs to go. Very few of today's homes lack the necessary utility capacity to support an EV charger, especially if it is used mainly at night. My charger drew about the same as an electric clothes dryer (30A @ 240V). A timer kicked it on at midnight when the rates dropped, and it was always done well before morning.
Battery technology has improved remarkably over just the past decade. Just not as much as Moore's law (though few things have). Even so, old-fashioned lead-acid technology is surprisingly practical when combined with modern, efficient EV drive systems, tires and body designs. NiMH and Li-ion are even better. My NiMH EV1 had a range of 100-125 miles, which was actually much more than I needed in routine daily use. Li-ion EV prototypes with per-charge ranges approaching 300 miles have already been built and tested (AC Propulsion, IncCharging speed does need to be improved, but there are no really fundamental obstacles here. Most battery chemistries, including Li-ion, can be substantially recharged in an hour if enough power is available. Overnight at home, it's just not an issue but I could see a role for commercial high-power charging stations for daytime boost charging if needed.
After a brief splash, I'm seeing very little hype about fuel cells for laptops or mobile phones, and for good reason. The mobile phone application is especially silly given that today's phones can already remain on standby for days without recharging. Laptops are certainly more power-hungry than phones, but the power and energy densities of small fuel cells suitable for laptop use are still not there. Besides, how is it an improvement to have to go to the store to buy additional fuel for your laptop when you can just get it now from the nearest wall outlet in your home or office, 24 hours a day? For convenience and safety, you'd probably want to package the fuel in disposable cartridges. Even better, make the fuel solid so it can't spill. Such disposable solid-fuel cartridges are already available: they're called "alkaline batteries".
I suppose fuel cells might find a role when you're in a remote area without commercial power for a long period of time, but then again solar panels work well too.
I seriously doubt that the X-Prize will soon drive any nails into NASA's coffin. When Burt Rutan lands a couple of rovers on Mars and puts spacecraft into orbit around the gas giants, then they might have cause to be worried. If anything, the X-Prize may put a nail into the coffin of space joyriding, though I certainly hope not.
I thought there was just a bit of irony to the commentator's gushing remarks about the wonderfulness of privately-funded space exploration. I was watching over NASA-TV, a government-sponsored facility.
I'd like to know the basis for your 10 year prediction. That is, if it rests on anything besides wishful thinking. The computer industry has been driven by Moore's Law for the past four decades, with comparable improvements in optical communications and magnetic storage. I am unaware of any space propulsion technologies that have steadily doubled in performance or halved in cost every 18 months since the Mercury program, are you?
There already are quite a few private space companies. Some are large and well known, like Boeing and Lockheed-Martin. Others are small and not as well known, like Orbital Sciences. Yet none are enormously profitable. How many of Rutan's cheerleaders know that over a decade ago Orbital developed their own space launcher -- Pegasus -- that is also dropped from an airplane, but unlike SpaceShipOne, can reach orbit and has already placed quite a few satellites there?
Let's not forget the multinational and non-US space launch companies, like SeaLaunch and Arianespace, that have already captured much of the commercial market, along with the Russian, Japanese and Chinese spin-off companies. Every one of them has plenty of incentive to develop and commercialize any new launcher technologies that would give them an edge over the competition. But progress seems to be very slow, and this seems to be due to the nature of the beast. I just don't see any Intel microprocessors coming along to shake up the IBM mainframes of the space launch business. The low cost of Rutan's program (if you can call $23 M "low cost") I think has to do more with reduced expectations and cut corners than with any inherently cheap and innovative technology.
I wish I was wrong on all this, but I just don't think so.
That's just not true. When the solids are jettisoned, they have already burned out. What you see coming out of the nozzles is just residual char from the motor casings and nozzle. Remember the external atmospheric pressure is very low at that altitude.
If the solids were still producing appreciable thrust at jettison, then they'd fly forward quite rapidly since they're almost empty. But they don't. They just fall back after being pushed away by the separation motors.
Jettisoning the solids while they're still burning and producing thrust would produce a reasonably close re-enactment of the Challenger disaster.
An ongoing safety concern for the shuttle is ensuring that the two SRBs are as closely matched as possible throughout their entire burn. Even small temperature differences between them can be a big deal.
You don't understand. Sure, it's easier to build low-performance rocket engines. Sure, they're much safer and cheaper. But they're simply not enough, not if you want to reach orbit instead of being limited to quickie suborbital stunts with no meaningful future. Why do you think NASA and its international counterparts work so hard on developing advanced rocket engines despite the enormous challenges? Just to waste money?
The average man on the street doesn't understand that just achieving altitude, even 100 kilometers, is easy compared to entering orbit. Nearly all the energy it takes to orbit the shuttle goes into its kinetic energy, not its potential energy. Nor does the average man in the street understand that energy goes up as the square of velocity, nor does he know that the rocket equation that relates mass fraction to velocity is exponential. Heck, he probably doesn't even know what "exponential" means, or why that's bad.
The average man in the street thinks SpaceShipOne is now just a step away from going into orbit and replacing the shuttle, and that's just bunk. Rutan and company certainly know this, but they seem to enjoy the attention too much to point this out.
But the shuttle can eject the two SRBs (Solid Rocket Boosters) at any time and the three main engines of the shuttle itself are powered by internel fuel and the big foam External Fuel tank, which ejects after the SRB's anyway.
Wrong. The shuttle cannot shut down the solids once they are lit, and it cannot safely jettison the solids while they are still burning. That move would be immediately fatal. Once the SRBs are lit, the orbiter is along for the ride, for better or worse, until they burn out.
There is a way to (nearly) shut down the solids early: by firing the range safety
destruct system. This fires linear shaped charges running down the length of each SRB, splitting the case open and lowering the combustion chamber pressure
sufficiently for the propellant to stop rapid burning. This was actually done once,
some time after Challenger had already been destroyed by the aerodynamic forces resulting from its uncontrolled attitude after the external tank broke up (and not by the burning of the liquid hydrogen). As implied by the term "range safety destruct", this is something you do to protect people on the ground,
not the astronauts on the orbiter.
I wish Rutan et al well, but this whole X-Prize thing bothers me.
If these guys were investigating and developing a radical new
technology that's orders of magnitude cheaper than the
traditional ways of getting into space, then it would be really
interesting. Even a stunt like the X-Prize shot would be worthwhile to
help develop it. But it's not radical new
technology. It's just the same old chemical rocket stuff all over
again. With a lot of cut corners. (And, apparently, "unscripted
maneuvers").
And they're not even particularly good chemical rockets. Hybrid
rockets burning plastic/rubber/etc and N2O have inherently poorer
performance than, say, the hydrogen/oxygen engines that are common on
the upper stages of orbital launchers. Hybrids are simpler,
cheaper and safer, and they've become very popular among amateur
high-power rocketeers for this reason. They're fun. But they just
don't have the performance for a practical orbital launcher, as
opposed to a suborbital "stunt" flight. Or is "commercial manned space"
just about quickie zero-g joyrides for people with too much
money? I can already experience zero-g on an airplane or Six Flags'
Superman: The Escape a lot more cheaply.
The problem is that there just don't seem to be any radical, new
technologies promising to cut space access costs by orders of
magnitude just waiting for entrepreneurs to commercialize them. And
that means only a tiny handful of humans will ever be able to go into
space in our lifetime, and for at least several more. I wish it were
otherwise, but we have to face facts. In the meantime, we have to get
the very most out of the expensive launchers we do have, and that
means putting more and more capable robots into space to give us
earthbound humans the best vicarious experience of space travel we can
possibly get.
I'm also really put off by all this "go private enterprise, rah rah
rah" stuff, as if NASA is full of complete idiots. (It got so thick
the other morning that I had to turn the TV volume down.)
Who do they think
builds the rockets that NASA has been flying for decades? What about
the many space launchers that have already been fully commercialized?
And where did the money for SpaceShipOne really come from? (Hint:
what if the US Government were to actually enforce its antitrust laws
against large software companies?)
If you've got the money, you can already buy a launch from any of
several commercial companies, and only some of them are American. And
there are companies who routinely launch stuff and make money. Space
is already big business.
But when I look at SpaceShipOne and similar projects, I see a bunch of
rich guys publicly stroking their egos. SpaceShipOne is a dead-end hack.
I'd actually be completely
okay with that if only they would be more honest with the public about
what they're really doing.
I'm a little surprised to be hearing anything about hydrogen cars these days. Hydrogen fueled cars were heavily hyped a few years ago when the automakers were strong-arming the California Air Resources Board (CARB) to drop its near-term mandate for electric vehicles in favor of a promise for a few magical hydrogen-fueled cars some years in the future. The scam worked: CARB rescinded the EV mandate, many working EVs were pulled from their satisfied owners, and that's why you hear so little about hydrogen these days.
The simple facts are that hydrogen is not a source of energy, but rather an energy carrier, like electricity. And hydrogen is a rather poor energy carrier at that; it's far less efficient than the electric power grid, which already exists and goes almost everywhere. Hydrogen isn't even a good energy storage medium in a car, due to its extremely low density.
The fact is that there's nothing a hydrogen fuel-cell car can do that isn't already done better, more efficiently and more cheaply by a battery EV. Just when new battery technologies like nickel metal hydride and lithium-ion were starting to prove their worth in EVs, CARB pulls the rug out from under them.
I don't know why this is considered novel; there are other known substances that also solidify with increased temperature. One I'm pretty familiar with is pluronic lecithin organogel (PLO), widely used in compounding pharmacy as a base for transdermal (through the skin) medications. PLO carries the drug it's mixed with right through the skin and nearly disappears from the surface.
That was exactly how Scotty's character was originally defined. As far as he was concerned, the Enterprise was his. Kirk was just its driver.
I wasn't even 10 years old when I saw Scotty fix the damaged Enterprise bridge in the pilot episode Where No Man Has Gone Before. He was only a minor character in that episode, but right then I knew I wanted to be just like him when I grew up.:-)
Another advantage of a home land-line phone is that when you call 911, in most areas your street address is automatically displayed to the dispatcher. This can save valuable seconds in an emergency. If you call 911 on a cell phone, many dispatchers won't know where you are unless you tell them. Seems trivial enough, but emergencies have a way of making even smart people really stupid. And what if you're placing the call from a friend's house, and you can't quite remember the address?
In California, cellular 911 calls are routed to the California Highway Patrol, and it may take some time to reroute the call to your local police or fire department if you're calling from home.
Yes, the FCC has mandated position reporting on cellular 911 calls and the enabling technology is now common on newer phones, but many E911 call centers can't yet handle the information.
Nope, sorry. Sirius's orbits are designed to serve the northern latitudes, not the southern. It's certainly possible to build digital broadcast satellites to serve the south pole, but there's probably not much of a business case...
It is not possible to put a geostationary satellite over a pole. To be stationary, a satellite must be in a circular orbit over the equator with a period that exactly matches the earth's sidereal rotation rate. Such satellites are not visible at all from the poles.
It is possible, however, to use inclined orbits to provide good coverage at high latitudes, including the poles. You'll need multiple satellites to provide continuous coverage, though. It's my understanding that the South Pole links use retired geostationary satellites that have run out of stationkeeping propellant. Without stationkeeping, solar and lunar perturbations increase the orbital inclination, the angle between the orbital plane and the equator, which is nominally zero for a geostationary satellite. This causes the satellite to move in a north-south figure-8 pattern, making it visible for part of each day at each pole.
Two good examples of satellites in orbits specifically designed to provide good high latitude coverage are the Russian Molniya series and the new Sirius digital radio broadcasting satellites. (Sirius' competitor XM Radio uses conventional geostationary satellite orbits.)
Both Molniya and Sirius use elliptical orbits with inclinations of about 63 degrees. At this inclination, the effect of the earth's oblateness on the orbital argument of perigee is canceled out. That means the apogee (farthest point from the earth) will always occur at the same latitude, which in these two cases is selected to be the northernmost point of the orbit (since northern latitudes are being served). The result is a satellite that, while not stationary, spends much of each orbit nearly motionless at high latitude.
The Molniya and Sirius orbits differ in that the Molniya orbits have fairly low perigees and orbital periods of about 12 hours. The Sirius satellites are in geosynchronous (but not geostationary) orbits, meaning that even though they do not sit motionless over the equator, they still complete exactly one orbit per sidereal earth day.
The Russians use these orbits because their country sits at high latitudes. Sirius uses their orbits to increase the elevation at which their satellites appear over the northern US and southern Canada, minimizing blockage by buildings and reducing the number of terrestrial repeaters needed in urban areas.
A Sirius orbit can be seen here and a Molniya orbit can be seen here.
These things are far too common to get worked up about, and they still consume an infinitesmal fraction of my link capacity. I long ago stopped caring about unsuccessful intrusion attempts. I only care about the successful ones, and to help prevent those I apply all the usual safeguards.
I can't get this torrent to work. Both BitTorrent and Azureus on the Mac barf on it. So does btdownloadheadless on linux. I've used all three implementations to download many other torrents just fine, so I think there's something wrong with this file.
If your ISP is intrusive enough to read your email, then they can just as easily read it as it comes into your private mailserver.
Many (most?) MTAs now support the STARTTLS SMTP command. Set up your own mail server, create a self-signed certificate, and a remarkable fraction of your email will be automatically encrypted during the transfer. Even much of my incoming spam is encrypted in this way. Since it comes from all over the world, this actually serves as a useful mask for anyone doing traffic analysis.
Your ISP could still intercept your mail with a man-in-the-middle attack, but that's far less likely than browsing your mail files on their server.
I'd quickly find a new ISP if this was the case.
Well, mail server unreliability is a problem with many ISPs. Even though my ISP's server works most of the time, I still can't log in and run "mailq". I do that regularly with my own server, and I depend on it.
Not only is it bad netiquette to send massive attachments, but most servers will block them at the other end.
While I personally avoid sending large attachments, I can't reasonably object when it's done between consenting parties. So I don't see this as a valid argument against personal mail servers, but rather a strong argument in favor since the ISP's mail admin doesn't have to be a consenting party.
Have you heard of fetchmail?
Do you really want it to poll every minute? When you run your own mail server, you don't have to decide between overhead and quick notification of incoming email. Maybe you don't see the need to be notified of new email that quickly, but what right do you have to impose your personal preferences on others?
The bottom line is that I feel very strongly that there are many perfectly valid reasons for individuals to run their own mail servers, and no ISP should deny them this right as long as they don't bother anyone else, e.g., by sending spam.
This isn't just about the right to run personal email servers. It's about something much more important and fundamental: preserving and protecting the end-to-end model that made the Internet such a success. If we permit ISPs to encroach on the end-to-end principle for what may appear to the naive person to be "worthy" reasons, it won't end until it becomes almost impossible to innovate with new and useful end-to-end services.
Slashdot Mirror
I can't think of a better design for an amusement ride designed to produce weightlessness. It's my favorite. I usually like to make my camera float and dance around on the end of its carrying strap. It really is a pretty good zero-gee, unlike some rides where you're actively pulled down faster than free-fall (e.g., Disney's "Tower of Terror" and "Maliboomer").
Really? What about Boeing, Lockheed-Martin, Orbital Sciences, Arianespace, SeaLaunch and a couple of Russian and Chinese companies whose names I can't think of at the moment? They've been providing commercial space launch services for decades now. Or don't they count because they just launch boring unmanned satellites that lots of people on the ground actually find useful?
SpaceShipOne is for quickie suborbital jaunts only. Rutan is still far, far away from reaching orbit. Your $100K or whatever would buy you just 3.5 minutes of weightlessness at about $475/second. If you're willing to give up the view (SpaceShipOne's windows aren't that great anyway), you can experience weightlessness a lot more cheaply on an airplane ($3K for several 20-second periods) or for 6.5 seconds on the "Superman: The Escape" ride at Six Flags. A full-price Six Flags ticket is $47, so that's only $7.20/second even if you only ride once!
So I am always very skeptical whenever the major theme of some space-related startup seems to revolve more around bashing NASA than actually building a good product. It's not that NASA is terribly wonderful -- it has many problems -- but the simple truth is that the business of space flight is a lot harder than many naive entrepreneurs (and their lay cheerleaders) think it is.
Rutan is, by far, the most "real" space entrepreneur to come along in a long time. He clearly earned his X-Prize, and I congratulate him for it. But I sure do wish he'd ease off on his NASA-bashing and concede that space has always had plenty of room for both business and government, especially in cooperative projects. NASA may be a government institution, but it has a lot of real flesh-and-blood people who want to promote space exploration and development just as he does, and many of them are actually quite bright. Now that Rutan has finally reached the point NASA first passed in the late 1950s, he may discover that the next steps aren't quite as easy as he thought.
The "private enterprise in space" mantra is practically a religion with some people, and like most religions it's based more on wishful thinking than reality.
I find it most interesting that you would mention the Iridium/Globalstar/ICO failure, one of the most spectacular examples ever of a market flameout caused by ridiculously optimistic marketing estimates for a premium-priced service, and then maintain that there is nonetheless a big untapped market for $100,000 plane tickets from LAX to Sydney. The best way for really busy people to save time traveling is -- and remains -- telecommunications. And it works for the rest of us, not just the extremely wealthy.
Yes, I'm aware of the surveys that claim a lot of people would be willing to spend big bucks for a joyride into space. But you must know how those marketing surveys are conducted. There's a very big difference between casually saying "sure, why not" to the guy on the phone, and actually signing the check. Not to mention those liability waivers...
I have no problems with properly informed people risking their own lives (but not others' lives). It's a free country, or it's supposed to be. That means I also have the right to speak out when I see people being misled or sold a bill of goods. Especially when I think they're being misled about potential risks to their safety.
Personally, I think the only approach that will provide the many orders-of-magnitude reduction in cost necessary to colonize space on a large scale will be the space elevator. And the materials and engineering challenges are so daunting that there's virtually no chance of it occurring in my lifetime.
Safe, reliable and effective chemical rockets are inherently expensive. Based on what I've seen so far, Rutan has kept his costs down by substantially lowering his goals (quickie suborbital jaunts vs orbit) and by cutting substantial corners on safety and reliability. I actually cringed when I heard that he's going for the second prize flight today, because I don't think he has a clue why his last flight executed those "unscripted roll maneuvers". The last two SpaceShipOne flights both had some major unexpected problem that came close to disaster, and it's only by sheer luck that he hasn't yet lost a plane and its pilot. Unfortunately, he wants that X-Prize so badly that I think it has clouded his judgment.
I'm reminded of the many early Soviet "firsts" in manned space exploration that we later learned happened not because Soviet space technology was better than ours, but because they were much more willing to risk their pilots on PR stunts than we were. We saw how far that got them later on.
I sincerely hope Rutan succeeds tomorrow. But I fear his luck can't hold out forever.
Every space launch company has an incentive to innovate, cut costs and improve reliability. They compete with each other even (especially) when the government is the customer. Sure, there's room for more competition, but that's not the same as saying there's none.
I'm always amused when somebody crows about how much money will be saved by a new launcher that has never flown versus one that's been flying for a decade or more. It's as if the person has never heard of cost overruns and engineering setbacks, not to mention lowballing in the marketing department. I think I'd prefer to wait until a new launcher has a proven track record before I made those kinds of claims.
When electric cars become widespread and no longer require subsidies, we can easily solve the problem of raising money to build and maintain roads. You already have to tell your insurance company how much you drive every year. So give the state the same information when you renew your registration and they'll base the renewal fee on it.
How exactly is hydrogen power advancing? Automotive fuel cells are getting smaller and cheaper, but they don't seem to be getting significantly more efficient. About 50% from hydrogen gas to electricity seems to be par for the course. Combine that with the 70% efficiency of industrial-scale electrolyzers, and we're already down to a 35% end-to-end energy transmission efficiency even if the transmission and distribution infrastructure is 100% efficient and cost free. That compares to an end-to-end energy efficiency fo about 95% for the existing power grid. And I thought part of the point of all this was to help save energy and reduce global warming?
And what about the hydrogen storage problem?
The grid already does go just about everywhere it needs to go. Very few of today's homes lack the necessary utility capacity to support an EV charger, especially if it is used mainly at night. My charger drew about the same as an electric clothes dryer (30A @ 240V). A timer kicked it on at midnight when the rates dropped, and it was always done well before morning.
Battery technology has improved remarkably over just the past decade. Just not as much as Moore's law (though few things have). Even so, old-fashioned lead-acid technology is surprisingly practical when combined with modern, efficient EV drive systems, tires and body designs. NiMH and Li-ion are even better. My NiMH EV1 had a range of 100-125 miles, which was actually much more than I needed in routine daily use. Li-ion EV prototypes with per-charge ranges approaching 300 miles have already been built and tested (AC Propulsion, IncCharging speed does need to be improved, but there are no really fundamental obstacles here. Most battery chemistries, including Li-ion, can be substantially recharged in an hour if enough power is available. Overnight at home, it's just not an issue but I could see a role for commercial high-power charging stations for daytime boost charging if needed.
After a brief splash, I'm seeing very little hype about fuel cells for laptops or mobile phones, and for good reason. The mobile phone application is especially silly given that today's phones can already remain on standby for days without recharging. Laptops are certainly more power-hungry than phones, but the power and energy densities of small fuel cells suitable for laptop use are still not there. Besides, how is it an improvement to have to go to the store to buy additional fuel for your laptop when you can just get it now from the nearest wall outlet in your home or office, 24 hours a day? For convenience and safety, you'd probably want to package the fuel in disposable cartridges. Even better, make the fuel solid so it can't spill. Such disposable solid-fuel cartridges are already available: they're called "alkaline batteries".
I suppose fuel cells might find a role when you're in a remote area without commercial power for a long period of time, but then again solar panels work well too.
I thought there was just a bit of irony to the commentator's gushing remarks about the wonderfulness of privately-funded space exploration. I was watching over NASA-TV, a government-sponsored facility.
I'd like to know the basis for your 10 year prediction. That is, if it rests on anything besides wishful thinking. The computer industry has been driven by Moore's Law for the past four decades, with comparable improvements in optical communications and magnetic storage. I am unaware of any space propulsion technologies that have steadily doubled in performance or halved in cost every 18 months since the Mercury program, are you?
There already are quite a few private space companies. Some are large and well known, like Boeing and Lockheed-Martin. Others are small and not as well known, like Orbital Sciences. Yet none are enormously profitable. How many of Rutan's cheerleaders know that over a decade ago Orbital developed their own space launcher -- Pegasus -- that is also dropped from an airplane, but unlike SpaceShipOne, can reach orbit and has already placed quite a few satellites there?
Let's not forget the multinational and non-US space launch companies, like SeaLaunch and Arianespace, that have already captured much of the commercial market, along with the Russian, Japanese and Chinese spin-off companies. Every one of them has plenty of incentive to develop and commercialize any new launcher technologies that would give them an edge over the competition. But progress seems to be very slow, and this seems to be due to the nature of the beast. I just don't see any Intel microprocessors coming along to shake up the IBM mainframes of the space launch business. The low cost of Rutan's program (if you can call $23 M "low cost") I think has to do more with reduced expectations and cut corners than with any inherently cheap and innovative technology.
I wish I was wrong on all this, but I just don't think so.
If the solids were still producing appreciable thrust at jettison, then they'd fly forward quite rapidly since they're almost empty. But they don't. They just fall back after being pushed away by the separation motors.
Jettisoning the solids while they're still burning and producing thrust would produce a reasonably close re-enactment of the Challenger disaster.
An ongoing safety concern for the shuttle is ensuring that the two SRBs are as closely matched as possible throughout their entire burn. Even small temperature differences between them can be a big deal.
The average man on the street doesn't understand that just achieving altitude, even 100 kilometers, is easy compared to entering orbit. Nearly all the energy it takes to orbit the shuttle goes into its kinetic energy, not its potential energy. Nor does the average man in the street understand that energy goes up as the square of velocity, nor does he know that the rocket equation that relates mass fraction to velocity is exponential. Heck, he probably doesn't even know what "exponential" means, or why that's bad.
The average man in the street thinks SpaceShipOne is now just a step away from going into orbit and replacing the shuttle, and that's just bunk. Rutan and company certainly know this, but they seem to enjoy the attention too much to point this out.
Wrong. The shuttle cannot shut down the solids once they are lit, and it cannot safely jettison the solids while they are still burning. That move would be immediately fatal. Once the SRBs are lit, the orbiter is along for the ride, for better or worse, until they burn out.
There is a way to (nearly) shut down the solids early: by firing the range safety destruct system. This fires linear shaped charges running down the length of each SRB, splitting the case open and lowering the combustion chamber pressure sufficiently for the propellant to stop rapid burning. This was actually done once, some time after Challenger had already been destroyed by the aerodynamic forces resulting from its uncontrolled attitude after the external tank broke up (and not by the burning of the liquid hydrogen). As implied by the term "range safety destruct", this is something you do to protect people on the ground, not the astronauts on the orbiter.
If these guys were investigating and developing a radical new technology that's orders of magnitude cheaper than the traditional ways of getting into space, then it would be really interesting. Even a stunt like the X-Prize shot would be worthwhile to help develop it. But it's not radical new technology. It's just the same old chemical rocket stuff all over again. With a lot of cut corners. (And, apparently, "unscripted maneuvers").
And they're not even particularly good chemical rockets. Hybrid rockets burning plastic/rubber/etc and N2O have inherently poorer performance than, say, the hydrogen/oxygen engines that are common on the upper stages of orbital launchers. Hybrids are simpler, cheaper and safer, and they've become very popular among amateur high-power rocketeers for this reason. They're fun. But they just don't have the performance for a practical orbital launcher, as opposed to a suborbital "stunt" flight. Or is "commercial manned space" just about quickie zero-g joyrides for people with too much money? I can already experience zero-g on an airplane or Six Flags' Superman: The Escape a lot more cheaply.
The problem is that there just don't seem to be any radical, new technologies promising to cut space access costs by orders of magnitude just waiting for entrepreneurs to commercialize them. And that means only a tiny handful of humans will ever be able to go into space in our lifetime, and for at least several more. I wish it were otherwise, but we have to face facts. In the meantime, we have to get the very most out of the expensive launchers we do have, and that means putting more and more capable robots into space to give us earthbound humans the best vicarious experience of space travel we can possibly get.
I'm also really put off by all this "go private enterprise, rah rah rah" stuff, as if NASA is full of complete idiots. (It got so thick the other morning that I had to turn the TV volume down.) Who do they think builds the rockets that NASA has been flying for decades? What about the many space launchers that have already been fully commercialized? And where did the money for SpaceShipOne really come from? (Hint: what if the US Government were to actually enforce its antitrust laws against large software companies?)
If you've got the money, you can already buy a launch from any of several commercial companies, and only some of them are American. And there are companies who routinely launch stuff and make money. Space is already big business.
But when I look at SpaceShipOne and similar projects, I see a bunch of rich guys publicly stroking their egos. SpaceShipOne is a dead-end hack. I'd actually be completely okay with that if only they would be more honest with the public about what they're really doing.
The simple facts are that hydrogen is not a source of energy, but rather an energy carrier, like electricity. And hydrogen is a rather poor energy carrier at that; it's far less efficient than the electric power grid, which already exists and goes almost everywhere. Hydrogen isn't even a good energy storage medium in a car, due to its extremely low density.
The fact is that there's nothing a hydrogen fuel-cell car can do that isn't already done better, more efficiently and more cheaply by a battery EV. Just when new battery technologies like nickel metal hydride and lithium-ion were starting to prove their worth in EVs, CARB pulls the rug out from under them.
Call me cynical, but that seems to fit the facts.
I don't know why this is considered novel; there are other known substances that also solidify with increased temperature. One I'm pretty familiar with is pluronic lecithin organogel (PLO), widely used in compounding pharmacy as a base for transdermal (through the skin) medications. PLO carries the drug it's mixed with right through the skin and nearly disappears from the surface.
I wasn't even 10 years old when I saw Scotty fix the damaged Enterprise bridge in the pilot episode Where No Man Has Gone Before. He was only a minor character in that episode, but right then I knew I wanted to be just like him when I grew up. :-)
In California, cellular 911 calls are routed to the California Highway Patrol, and it may take some time to reroute the call to your local police or fire department if you're calling from home.
Yes, the FCC has mandated position reporting on cellular 911 calls and the enabling technology is now common on newer phones, but many E911 call centers can't yet handle the information.
Nope, sorry. Sirius's orbits are designed to serve the northern latitudes, not the southern. It's certainly possible to build digital broadcast satellites to serve the south pole, but there's probably not much of a business case...
It is possible, however, to use inclined orbits to provide good coverage at high latitudes, including the poles. You'll need multiple satellites to provide continuous coverage, though. It's my understanding that the South Pole links use retired geostationary satellites that have run out of stationkeeping propellant. Without stationkeeping, solar and lunar perturbations increase the orbital inclination, the angle between the orbital plane and the equator, which is nominally zero for a geostationary satellite. This causes the satellite to move in a north-south figure-8 pattern, making it visible for part of each day at each pole.
Two good examples of satellites in orbits specifically designed to provide good high latitude coverage are the Russian Molniya series and the new Sirius digital radio broadcasting satellites. (Sirius' competitor XM Radio uses conventional geostationary satellite orbits.)
Both Molniya and Sirius use elliptical orbits with inclinations of about 63 degrees. At this inclination, the effect of the earth's oblateness on the orbital argument of perigee is canceled out. That means the apogee (farthest point from the earth) will always occur at the same latitude, which in these two cases is selected to be the northernmost point of the orbit (since northern latitudes are being served). The result is a satellite that, while not stationary, spends much of each orbit nearly motionless at high latitude.
The Molniya and Sirius orbits differ in that the Molniya orbits have fairly low perigees and orbital periods of about 12 hours. The Sirius satellites are in geosynchronous (but not geostationary) orbits, meaning that even though they do not sit motionless over the equator, they still complete exactly one orbit per sidereal earth day.
The Russians use these orbits because their country sits at high latitudes. Sirius uses their orbits to increase the elevation at which their satellites appear over the northern US and southern Canada, minimizing blockage by buildings and reducing the number of terrestrial repeaters needed in urban areas.
A Sirius orbit can be seen here and a Molniya orbit can be seen here.
With today's RAM prices, it's much easier to just do without a swap partition altogether.
These things are far too common to get worked up about, and they still consume an infinitesmal fraction of my link capacity. I long ago stopped caring about unsuccessful intrusion attempts. I only care about the successful ones, and to help prevent those I apply all the usual safeguards.
I can't get this torrent to work. Both BitTorrent and Azureus on the Mac barf on it. So does btdownloadheadless on linux. I've used all three implementations to download many other torrents just fine, so I think there's something wrong with this file.
Many (most?) MTAs now support the STARTTLS SMTP command. Set up your own mail server, create a self-signed certificate, and a remarkable fraction of your email will be automatically encrypted during the transfer. Even much of my incoming spam is encrypted in this way. Since it comes from all over the world, this actually serves as a useful mask for anyone doing traffic analysis.
Your ISP could still intercept your mail with a man-in-the-middle attack, but that's far less likely than browsing your mail files on their server.
Well, mail server unreliability is a problem with many ISPs. Even though my ISP's server works most of the time, I still can't log in and run "mailq". I do that regularly with my own server, and I depend on it.
While I personally avoid sending large attachments, I can't reasonably object when it's done between consenting parties. So I don't see this as a valid argument against personal mail servers, but rather a strong argument in favor since the ISP's mail admin doesn't have to be a consenting party.
Do you really want it to poll every minute? When you run your own mail server, you don't have to decide between overhead and quick notification of incoming email. Maybe you don't see the need to be notified of new email that quickly, but what right do you have to impose your personal preferences on others?
The bottom line is that I feel very strongly that there are many perfectly valid reasons for individuals to run their own mail servers, and no ISP should deny them this right as long as they don't bother anyone else, e.g., by sending spam.
This isn't just about the right to run personal email servers. It's about something much more important and fundamental: preserving and protecting the end-to-end model that made the Internet such a success. If we permit ISPs to encroach on the end-to-end principle for what may appear to the naive person to be "worthy" reasons, it won't end until it becomes almost impossible to innovate with new and useful end-to-end services.