Even for a modest exhaust velocity of 2000m/s of the rocket and a terminal velocity of 100m/s (the atmosphere does most of the breaking for you anyway), only about 5% of the total mass need to be fuel to land. That's about 20kg of fuel for a total mass of 300kg of the whole rig including the shaved ape. There's also a healthy safety margin for hovering and fooling around before touchdown, especially if you use somewhat better rocket fuel. (2000m/s isn't all that great).
If you had listened to the commentary after the launch, you would have heard the boss of OSC rattling down a laundry list of companies doing stuff for them - including external companies doing the ground systems and the separation systems (which I distinctly remember). Basically everything was done by somebody else.
The whole second stage is from ATK, made using the same factories where they usually build ICBMs. The first stage engines are 1970ies Soviet relics. The rest of the first stage (tanks, thrust structures etc.) was build by Yuzhmash a state-owned Ukranian rocket builder. The Cygnus spacecraft will be provided by Tahles Alenia Space, which itself stretches the definition of "private".
Ahh, a summary of all those thing that have been proven to be the worst in HINDSIGHT, neatly compressed. Just leaving out all those things that, at the time, did not point to the development and that led former fascists to defend their actions for decades afterwards.
Just because you don't take those apologists seriously anymore, does not mean they weren't taken seriously back in their day.
Absolutely. And it wasn't just the lockdown of the whole city, but also a "public safety exception" voiding the constitutional right to have a lawyer. I think we witnessed an object lesson in history. How did fascism take over Germany? One perfectly justifiable step after another. Why didn't people object? Only few did and all the others said "shut up".
I would be much more interested in the role of convective heat transfer in the climate models he inspected. It is clear that this is much more important on the surface than radiative transfer and I'd certainly like to know whether they can make a decent job of modeling it or not.
It's not just subsidies. When Spain went broke and had to limit its feed-in tariffs from insanely high levels down to longterm sustainable levels, it took some 40% of worldwide demand for solar panels with it. Other countries faced similar problems. Only Germany maintained the insane feed-in tariffs (accounting for about $300bn on solar so far, resulting in the highest electricity prices worldwide).
But even in Germany the economic crisis reduced investment well below expectations. Excessive supply from factories build before the economic crisis hugely outstripped demand. Prices collapsed below cost and companies go broke.
Which is also the reason why solar power seems to be becoming cheaper. It's not the cost that is getting cheaper - everybody is still using the same old factories and the same old technology. It is merely the price being pushed down to unsustainable levels.
Wait for conspiracy theories that will be created, once prices start to rise again and the expected exponential fall of the cost of solar power doesn't happen.
What the fuck? People are being relocated FOR WINDMILLS in CANADA?
It is kind of understandable to relocated people for lignite stripmines in Germany - because people happen to live where there is lignite in the ground and everybody is against fracking and nuclear. But relocating people for windmills in a country with 1.5% the population density of Germany is just mind-blowing - mind you, Germany managed without relocating people despite having 240 people per sqkm, whereas Canada has a mere 3.7 people per sqkm.
If those people are upset, they are upset for good reason.
The psychosomatic consequences of windpower are nothing that should stop anybody from building windfarms. But when people in Japan, who have barely been exposed to any significant radiation at all, start complaining about imaginary symptoms of their exposure to radiation (as well as very real symptoms of unchecked overdosing on iodine) this is just yet another reason to do away with nuclear power.
We know all km-sized asteroids including their trajectories for centuries - that's because they are few and stick out like a sore thumb in comparison with a 28m (equivalent) asteroid like 2012-DA14.
The danger are those asteroids we don't know about - and those are the small ones.
Using gravity to slowly nudge an asteroid from its trajectory is impractical and a foolish suggestion. Why?
All asteroids large enough to make this work are known and known not to collide with earth. All asteroids that are a threat to earth are small, unknown and liable to be discovered only a relatively short time - certainly not decades - before impacting earth. There is also good reason to expect those to be more common than the claim that they only hit earth "once a century". A typical dangerous asteroid to be discovered will measure between 15m and 100m. That's a simple matter of the chance to detect such asteroids being very small, while the numbers in which they occur are much larger than anything in the several 100m or km class.
We also happen to have just right stuff to do something about the typical asteroids - rockets capable to carry a few tons of stuff beyond earth orbit, anywhere within the solar system. Crash a compact impactor (lead, steel, depleted uranium... whatever) into the asteroid at your typical speed of 10km/s or more (depending on the exact trajectory and propulsion used) and the kinetic energy released will be sufficient to break it up into small enough pieces. Each ton of material impacting at this speed has the energy of four Tallboy bombs. Those had enough energy to make craters 24m deep and 30m wide on earth.
This works because the large energy is carried by a small mass with little momentum of itself, which means that the energy will be released in all directions, just like a conventional bomb would. Such a collision creates debris small enough to burn up harmlessly in the atmosphere (albeit in spectacular fashion).
As others said, Dragon doesn't use LOX or other cryogenic fuel.
However, the upper stage does - and I was rather impressed with the ice buildup inside Dragons trunk section during separation. So some parts of it might or might not have gotten colder than they were supposed to.
You're underestimating the scaling. The destruction caused by a meteor blowing up in the atmosphere also depends on the altitude. A meteor of twice the size will last longer and blow up much closer to the ground. (Especially when it doesn't strike at such a shallow angle.) Half the distance means four times the pressure (at least for a small area near the "explosion"). At about 100m size it won't break up before hitting the ground... the only good news is that after this, energy does indeed scale with velocity and mass.
The Russians got incredibly lucky with that one. A 25m asteroid (or a 20m asteroid at a steep angle) would have caused a ten times stronger blast - that would have destroyed brickwalls instead of just windows.
Who is solving problems? People who are shouting and screaming, painting nice little plackards for demonstrations, chanting and getting drunk on their "success"...... or people who sit down to develop and build the alternatives?
You're right it's the wrong word. The point is, it is the decomposition of the stuff itself.
When you are burning TNT with air (a perfectly safe thing to do, btw, so long as there is no primary explosive around), you'll get about ten times as much energy out of it.
The one thing that strikes me these days, is the way how the exact same people who solved the problems you are talking about - DDT, leaded gasoline, smog etc. - are still demonized and portait as plotting to destroy the earth.
They are car companies installing catalytic converters, oil companies developing anti-knocking agents without lead, power companies installing filters in their power plants, companies building spraycans, freezers, air-conditioners, styrofoam etc without CFCs and so on.
So, despite "serious" news agencies (like Associated Press) saying otherwise, it turns out this thing wasn't just a 10 ton asteroid. Which isn't entirely unsurprising. Getting a shockwave like that simply took the energy of a small thermonuclear warhead.
Now I'm still wondering, what about the reports that the russians tried to shoot down the asteroid? It's not unrealistic it's like... almost real!
(Hint: The Hiroshima bomb (15kt) just about managed to break windows at 20km distance - and the altitude of breakup was at least 30km according to most sources.)
Slashdot Mirror
Actually, you need surprisingly little fuel.
Even for a modest exhaust velocity of 2000m/s of the rocket and a terminal velocity of 100m/s (the atmosphere does most of the breaking for you anyway), only about 5% of the total mass need to be fuel to land. That's about 20kg of fuel for a total mass of 300kg of the whole rig including the shaved ape. There's also a healthy safety margin for hovering and fooling around before touchdown, especially if you use somewhat better rocket fuel. (2000m/s isn't all that great).
If you had listened to the commentary after the launch, you would have heard the boss of OSC rattling down a laundry list of companies doing stuff for them - including external companies doing the ground systems and the separation systems (which I distinctly remember). Basically everything was done by somebody else.
The whole second stage is from ATK, made using the same factories where they usually build ICBMs. The first stage engines are 1970ies Soviet relics. The rest of the first stage (tanks, thrust structures etc.) was build by Yuzhmash a state-owned Ukranian rocket builder. The Cygnus spacecraft will be provided by Tahles Alenia Space, which itself stretches the definition of "private".
Ahh, a summary of all those thing that have been proven to be the worst in HINDSIGHT, neatly compressed. Just leaving out all those things that, at the time, did not point to the development and that led former fascists to defend their actions for decades afterwards.
Just because you don't take those apologists seriously anymore, does not mean they weren't taken seriously back in their day.
Absolutely. And it wasn't just the lockdown of the whole city, but also a "public safety exception" voiding the constitutional right to have a lawyer. I think we witnessed an object lesson in history. How did fascism take over Germany? One perfectly justifiable step after another. Why didn't people object? Only few did and all the others said "shut up".
It was a bleak day. That I won't forget.
Anything in html tags doesn't seem to count.
Nor do code blocks.
Just judging from the apperance of the post.
I would be much more interested in the role of convective heat transfer in the climate models he inspected. It is clear that this is much more important on the surface than radiative transfer and I'd certainly like to know whether they can make a decent job of modeling it or not.
It's not just subsidies. When Spain went broke and had to limit its feed-in tariffs from insanely high levels down to longterm sustainable levels, it took some 40% of worldwide demand for solar panels with it. Other countries faced similar problems. Only Germany maintained the insane feed-in tariffs (accounting for about $300bn on solar so far, resulting in the highest electricity prices worldwide).
But even in Germany the economic crisis reduced investment well below expectations. Excessive supply from factories build before the economic crisis hugely outstripped demand. Prices collapsed below cost and companies go broke.
Which is also the reason why solar power seems to be becoming cheaper. It's not the cost that is getting cheaper - everybody is still using the same old factories and the same old technology. It is merely the price being pushed down to unsustainable levels.
Wait for conspiracy theories that will be created, once prices start to rise again and the expected exponential fall of the cost of solar power doesn't happen.
What the fuck? People are being relocated FOR WINDMILLS in CANADA?
It is kind of understandable to relocated people for lignite stripmines in Germany - because people happen to live where there is lignite in the ground and everybody is against fracking and nuclear. But relocating people for windmills in a country with 1.5% the population density of Germany is just mind-blowing - mind you, Germany managed without relocating people despite having 240 people per sqkm, whereas Canada has a mere 3.7 people per sqkm.
If those people are upset, they are upset for good reason.
The improvement of reception is just as noteworthy!
That's what you call double standards.
The psychosomatic consequences of windpower are nothing that should stop anybody from building windfarms. But when people in Japan, who have barely been exposed to any significant radiation at all, start complaining about imaginary symptoms of their exposure to radiation (as well as very real symptoms of unchecked overdosing on iodine) this is just yet another reason to do away with nuclear power.
We know all km-sized asteroids including their trajectories for centuries - that's because they are few and stick out like a sore thumb in comparison with a 28m (equivalent) asteroid like 2012-DA14.
The danger are those asteroids we don't know about - and those are the small ones.
Using gravity to slowly nudge an asteroid from its trajectory is impractical and a foolish suggestion. Why?
All asteroids large enough to make this work are known and known not to collide with earth. All asteroids that are a threat to earth are small, unknown and liable to be discovered only a relatively short time - certainly not decades - before impacting earth. There is also good reason to expect those to be more common than the claim that they only hit earth "once a century". A typical dangerous asteroid to be discovered will measure between 15m and 100m. That's a simple matter of the chance to detect such asteroids being very small, while the numbers in which they occur are much larger than anything in the several 100m or km class.
We also happen to have just right stuff to do something about the typical asteroids - rockets capable to carry a few tons of stuff beyond earth orbit, anywhere within the solar system. Crash a compact impactor (lead, steel, depleted uranium ... whatever) into the asteroid at your typical speed of 10km/s or more (depending on the exact trajectory and propulsion used) and the kinetic energy released will be sufficient to break it up into small enough pieces. Each ton of material impacting at this speed has the energy of four Tallboy bombs. Those had enough energy to make craters 24m deep and 30m wide on earth.
This works because the large energy is carried by a small mass with little momentum of itself, which means that the energy will be released in all directions, just like a conventional bomb would. Such a collision creates debris small enough to burn up harmlessly in the atmosphere (albeit in spectacular fashion).
As others said, Dragon doesn't use LOX or other cryogenic fuel.
However, the upper stage does - and I was rather impressed with the ice buildup inside Dragons trunk section during separation. So some parts of it might or might not have gotten colder than they were supposed to.
You're underestimating the scaling. The destruction caused by a meteor blowing up in the atmosphere also depends on the altitude. A meteor of twice the size will last longer and blow up much closer to the ground. (Especially when it doesn't strike at such a shallow angle.) Half the distance means four times the pressure (at least for a small area near the "explosion"). At about 100m size it won't break up before hitting the ground ... the only good news is that after this, energy does indeed scale with velocity and mass.
The Russians got incredibly lucky with that one. A 25m asteroid (or a 20m asteroid at a steep angle) would have caused a ten times stronger blast - that would have destroyed brickwalls instead of just windows.
Who is solving problems? People who are shouting and screaming, painting nice little plackards for demonstrations, chanting and getting drunk on their "success" ... ... or people who sit down to develop and build the alternatives?
Now guess who is who.
You're right it's the wrong word. The point is, it is the decomposition of the stuff itself.
When you are burning TNT with air (a perfectly safe thing to do, btw, so long as there is no primary explosive around), you'll get about ten times as much energy out of it.
I followed the trail of over $500billion spend on "renewables" in Germany ... now guess what I found.
Sheep come in herds. They stick together and mindlessly shout the same thing.
5 out of 5 respondents agree that big business follows the law. You certainly don't hear that very often.
So long as there is a consensus at least in this point, you may want to go ahead and agree on what better laws should look like.
The one thing that strikes me these days, is the way how the exact same people who solved the problems you are talking about - DDT, leaded gasoline, smog etc. - are still demonized and portait as plotting to destroy the earth.
They are car companies installing catalytic converters, oil companies developing anti-knocking agents without lead, power companies installing filters in their power plants, companies building spraycans, freezers, air-conditioners, styrofoam etc without CFCs and so on.
Could you give me a reference for that? Thanks.
By convention, it is the energy released by spontaneous decomposition of 1000t of trinitrotoluol - or 4.2 TJ of energy.
So, despite "serious" news agencies (like Associated Press) saying otherwise, it turns out this thing wasn't just a 10 ton asteroid. Which isn't entirely unsurprising. Getting a shockwave like that simply took the energy of a small thermonuclear warhead.
Now I'm still wondering, what about the reports that the russians tried to shoot down the asteroid? It's not unrealistic it's like ... almost real!
I've written a more lengthy piece on this. In short: No way.
(Hint: The Hiroshima bomb (15kt) just about managed to break windows at 20km distance - and the altitude of breakup was at least 30km according to most sources.)