This is exactly the problem. H2O2 can be violently reactive and in fact can even be hypergolic if mixed with certain compounds
LOX is a powerful oxidizer, too, and reacts explosively even with a greasy fingerprint. With a 90 degrees kelvin boiling temperature it can cause severe cold burns, troublesome ice condensation and makes most materials brittle and more prone to failure.
The Nazi's found this out with their Me163's which actually had more losses due to refueling than combat losses
The problems early German and British rocket builders had with H2O2 are probably related to impurities that caused it to spontaneously decompose. High purity H2O2 available today, handled and stored properly in clean compatible containers and treated with respect is relatively safe.
Chemical, semiconductors and other industries regularly handle much nastier compounds and they are regularly transported in tanker trucks that may be passing not far from your home.
The relative safety of a compound is largely a matter of perception, not fact.
Lee Abrams is also known as Mr. Laser Beam (an anagram of "Lee Abrams"). He did the narration in "Let's Talk About Me" on the Alan Parsons Project album "Vulture Culture'.
What's amazing is that this dude in Bum#@!$ Egypt can get nice service like that and, ta-da, run a web site
Nope, the web site is hosted by Interland in Atlanta GA. He is paying no less than $16.95/mo (their cheapest plan).
where most people in the US have to beg their ISP or Tripod or some other advert hole for 10 big megs of space.
Only if they spend more time whining than looking for an alternative. Check out Nearly Free Speech. $1/1GB transferred, no monthly payment, no setup fees. For a personal site you can just put a few bucks in your account and they will last virtually forever. Even a slashdotting shouldn't hurt too much - other providers charge much more than that per GB if you exceed your monthly limit.
With paraffin fuel you still need an oxidizer. To keep it environmentally friendly that would be either liquid oxygen (cryogenic, hard to handle) or... hydrogen peroxide!
Compared to cryogenics peroxide is not so nasty. What Armadillo Aerospace is doing is to build a rocket at low cost using proven technologies. What the article is talking about is new research.
Carmack is moving from the peroxide monopropellant used in the first experiments to a peroxide-kerosene combination which probably has higher Isp than paraffin. The only advantage of paraffin is that it's solid and can be used in a hybrid rocket. While hybrid rockets have some interesting advantages I don't really see the point of developing new technology when existing technology can be make almost two orders of magnitude cheaper. Well, actually I do see the point - it's an excuse to spend more money on research and new technology and keep more people on the payroll. That's what NASA is all about.
This is just sick. I don't think I could even think about eating this. Anyone else feel the same way?
Nope. I'm no vegetarian but I don't see how this is any more or less sick than killing animals and eating their flesh.
This is not genetically engineered food. It's natural muscle tissue (i.e. meat) grown in vitro instead of in vivo. You can think of it as hydroponic meat.
Re:Dozens of ballons, or three satellites
on
Wi-Fi From The Sky
·
· Score: 2
Dozens of balloons will give you thousands of times more bandwidth than three satellites.
Geostationary satellites are 22000 miles away. It takes powerful transmitters and big dishes for the signal to get through, especially as frequency shortage pushes the signals to ever-higher frequencies that are much more susceptible to weather interference. High-speed mobile terminals are out of the question because of power and antenna limitations. Even if they were practical - where would you get the bandwith for it? From so high up it's not possible to achieve a good frequency reuse factor using directional antenna arrays.
LEO satellites are much closer (hundreds of miles) but they are not geostationary. You need a whole constellation of them and until they're all up you don't gete continuous coverage anywhere. This makes it very difficult to grow your business slowly - you need a huge up-front investment. Your customers are not exactly distributed uniformly around the globe, either, so you have lots of unused capacity (=expensive hardware) where you don't need it and not enough where you need it the most.
Directional antenna arrays lets you re-use frequencies efficiently. Since the platform is more-or-less equally distant from all ground terminals it solves the near-far problem and allows the use of arrays with relatively weak side-lobe attenuation.
The interference from a WiFi-equipped laptop one foot away from a signal cable passing through the plane is millions of times stronger than a stratospheric communication platform hovering a several miles above it.
The author suspects that since neural thresholds are continously calibrated they could be affected by prolonged exposure to sounds with significant energy just below the masking threshold. This is a valid theory that definitely merits further research.
The author's claim that his tinnitus condition results from this is as flawed as the claims of most pseudoscientific texts that rely on anecdotal evidence instead of statistical research. Mentioning "subliminal messages" and "overpriced CDs" further reduces the credibility of this article.
Reading LotR again after reading the Silmarillion is a very different experience. You suddenly spot lots of references and everything fits into a bigger scheme.
From the article: "...An earlier version that covered the legs was unpopular with workers, who had to remove the contraption whenever they took off their shoes. "
The internet was also another technology that was spreading fast but failed to bring lots of profits. Most of the money moving around was investments, not actual revenue. There are no easy profits. There are always competitors, margins are razor-thin and even if you are doing well you need to watch your back for the one that will bring you down. In other words - business as usual.
That is, of course, unless you found some way to create a monopoly and maintain it. Monopolists are the only ones that get the goose that lays golden eggs. WiFi is not going to be that goose.
Looking at the cost per kg is not really relevant when comparing a rocket carrying a 12.5 ton payload with a rocket designed for a 470 kg microsatellite. The cost/kg is always higher for small payloads. For a small payload this is actually pretty cheap - about half the cost of the Orbital Sciences Pegasus.
BTW, the first stage of Musk's Falcon LV is supposed to be reusable. Getting down to $0.5K $1K range is possible only if you make dozens of launches per year but the market for microsatellites just isn't that big.
The private sector doesn't want anything to do with manned spaceflight
The solution is simple: separate people and cargo. A cargo launcher needs to be cheap and have a pretty good chance to reach orbit. The private sector can handle that just fine, thank you. Reusable or expendable, horizontal or vertical launch and landing - whatever. Let the market sort it out. NASA should just commit to buying orbital delivery services and not compete with their own suppliers with your tax dollars.
A crew taxi vehicle needs to have a good chance of reaching orbit and an excellent chance of bringing the passengers back alive in case it doesn't. In other words, it must have effective abort modes in all stages of the launch. NASA will handle this part.
NASA: manned operations, deep space probes, science stuff and X vehicles.
Private sector: Orbital delivery. Off-limits to NASA.
There's no use in having a comm satellite designed for geosynchronous orbit as a lawn ornament on the ISS.
A possible rescue mission would be to capture it with the space shuttle, attach a booster and transfer it to its intended orbit and orbital slot. I doubt it will be cost-effective, though.
BTW, it was insured.
What's more addictive than crack???
on
Virtual Simerica
·
· Score: 3, Funny
Slashdot Mirror
This is exactly the problem. H2O2 can be violently reactive and in fact can even be hypergolic if mixed with certain compounds
LOX is a powerful oxidizer, too, and reacts explosively even with a greasy fingerprint. With a 90 degrees kelvin boiling temperature it can cause severe cold burns, troublesome ice condensation and makes most materials brittle and more prone to failure.
The Nazi's found this out with their Me163's which actually had more losses due to refueling than combat losses
The problems early German and British rocket builders had with H2O2 are probably related to impurities that caused it to spontaneously decompose. High purity H2O2 available today, handled and stored properly in clean compatible containers and treated with respect is relatively safe.
Chemical, semiconductors and other industries regularly handle much nastier compounds and they are regularly transported in tanker trucks that may be passing not far from your home.
The relative safety of a compound is largely a matter of perception, not fact.
"Fire advise google"
Lee Abrams is also known as Mr. Laser Beam (an anagram of "Lee Abrams"). He did the narration in "Let's Talk About Me" on the Alan Parsons Project album "Vulture Culture'.
The recoring area of a DVD is 14 square inches. So the density of this new recording technique is 14*47=658 times greater than a DVD.
What's amazing is that this dude in Bum#@!$ Egypt can get nice service like that and, ta-da, run a web site
Nope, the web site is hosted by Interland in Atlanta GA. He is paying no less than $16.95/mo (their cheapest plan).
where most people in the US have to beg their ISP or Tripod or some other advert hole for 10 big megs of space.
Only if they spend more time whining than looking for an alternative. Check out Nearly Free Speech. $1/1GB transferred, no monthly payment, no setup fees. For a personal site you can just put a few bucks in your account and they will last virtually forever. Even a slashdotting shouldn't hurt too much - other providers charge much more than that per GB if you exceed your monthly limit.
With paraffin fuel you still need an oxidizer. To keep it environmentally friendly that would be either liquid oxygen (cryogenic, hard to handle) or... hydrogen peroxide!
Compared to cryogenics peroxide is not so nasty. What Armadillo Aerospace is doing is to build a rocket at low cost using proven technologies. What the article is talking about is new research.
Carmack is moving from the peroxide monopropellant used in the first experiments to a peroxide-kerosene combination which probably has higher Isp than paraffin. The only advantage of paraffin is that it's solid and can be used in a hybrid rocket. While hybrid rockets have some interesting advantages I don't really see the point of developing new technology when existing technology can be make almost two orders of magnitude cheaper. Well, actually I do see the point - it's an excuse to spend more money on research and new technology and keep more people on the payroll. That's what NASA is all about.
Not sure what kinds of paraffins would have the kind of energy density they would need for rocketry level thrust, maybe aromatics?
They are looking for high burn rate (thrust), not high specific impulse (efficiency). That's what you need in a booster.
Is that anything like the much needed Sex Patch?
$ patch -p0 < human_male-1.3.7-multiple-orgasms.diff
We now know that low-level radiation is simply far less harmful (and far better understood) than we thought it was in the 1950's.
In fact, there is evidence that low-level radiation is actually beneficial. This effect is known as Radiation Hormesis
What it all comes down to is doing something you love.
What it all comes down to is the the reward cascade in your limbic system.
This is just sick. I don't think I could even think about eating this. Anyone else feel the same way?
Nope. I'm no vegetarian but I don't see how this is any more or less sick than killing animals and eating their flesh.
This is not genetically engineered food. It's natural muscle tissue (i.e. meat) grown in vitro instead of in vivo. You can think of it as hydroponic meat.
Dozens of balloons will give you thousands of times more bandwidth than three satellites.
Geostationary satellites are 22000 miles away. It takes powerful transmitters and big dishes for the signal to get through, especially as frequency shortage pushes the signals to ever-higher frequencies that are much more susceptible to weather interference. High-speed mobile terminals are out of the question because of power and antenna limitations. Even if they were practical - where would you get the bandwith for it? From so high up it's not possible to achieve a good frequency reuse factor using directional antenna arrays.
LEO satellites are much closer (hundreds of miles) but they are not geostationary. You need a whole constellation of them and until they're all up you don't gete continuous coverage anywhere. This makes it very difficult to grow your business slowly - you need a huge up-front investment. Your customers are not exactly distributed uniformly around the globe, either, so you have lots of unused capacity (=expensive hardware) where you don't need it and not enough where you need it the most.
Directional antenna arrays lets you re-use frequencies efficiently. Since the platform is more-or-less equally distant from all ground terminals it solves the near-far problem and allows the use of arrays with relatively weak side-lobe attenuation.
The interference from a WiFi-equipped laptop one foot away from a signal cable passing through the plane is millions of times stronger than a stratospheric communication platform hovering a several miles above it.
The author suspects that since neural thresholds are continously calibrated they could be affected by prolonged exposure to sounds with significant energy just below the masking threshold. This is a valid theory that definitely merits further research.
The author's claim that his tinnitus condition results from this is as flawed as the claims of most pseudoscientific texts that rely on anecdotal evidence instead of statistical research. Mentioning "subliminal messages" and "overpriced CDs" further reduces the credibility of this article.
So that's why Sauron made a ring of power instead of a bracelet of power!
Reading LotR again after reading the Silmarillion is a very different experience. You suddenly spot lots of references and everything fits into a bigger scheme.
Highly recommended.
From the article: "...An earlier version that covered the legs was unpopular with workers, who had to remove the contraption whenever they took off their shoes. "
Where did you get to try this?
This article in Wired from 1999 describes an airbag vest developed by Japanese construction giant Kajima to protect construction workers from falls.
The internet was also another technology that was spreading fast but failed to bring lots of profits. Most of the money moving around was investments, not actual revenue. There are no easy profits. There are always competitors, margins are razor-thin and even if you are doing well you need to watch your back for the one that will bring you down. In other words - business as usual.
That is, of course, unless you found some way to create a monopoly and maintain it. Monopolists are the only ones that get the goose that lays golden eggs. WiFi is not going to be that goose.
Looking at the cost per kg is not really relevant when comparing a rocket carrying a 12.5 ton payload with a rocket designed for a 470 kg microsatellite. The cost/kg is always higher for small payloads. For a small payload this is actually pretty cheap - about half the cost of the Orbital Sciences Pegasus.
BTW, the first stage of Musk's Falcon LV is supposed to be reusable. Getting down to $0.5K $1K range is possible only if you make dozens of launches per year but the market for microsatellites just isn't that big.
Google is great, but how about a real trademark search?
The private sector doesn't want anything to do with manned spaceflight
The solution is simple: separate people and cargo. A cargo launcher needs to be cheap and have a pretty good chance to reach orbit. The private sector can handle that just fine, thank you. Reusable or expendable, horizontal or vertical launch and landing - whatever. Let the market sort it out. NASA should just commit to buying orbital delivery services and not compete with their own suppliers with your tax dollars.
A crew taxi vehicle needs to have a good chance of reaching orbit and an excellent chance of bringing the passengers back alive in case it doesn't. In other words, it must have effective abort modes in all stages of the launch. NASA will handle this part.
NASA: manned operations, deep space probes, science stuff and X vehicles.
Private sector: Orbital delivery. Off-limits to NASA.
There's no use in having a comm satellite designed for geosynchronous orbit as a lawn ornament on the ISS.
A possible rescue mission would be to capture it with the space shuttle, attach a booster and transfer it to its intended orbit and orbital slot. I doubt it will be cost-effective, though.
BTW, it was insured.
Let's call it EverSlashdot