According to this article [spaceflightnow.com], they could evacuate 6 in the emergency soyuz capsule.
Actually, I think the
article says the Russian Enterprise module is capable of docking two Soyuz capsules, each of which can evacuate six crew members, for a total of six.
The ISS only bear three permanent crew members, between shuttle flights, now, because that is the total number that can be evacuated by the single Soyuz it has mounted now.
The Soyuz are replaced every six months. There was recent talk of building more Apollo capsules, if the Russians can't afford to build more Soyuz.
A recent American law prevents them from paying for Russian Soyuz.
About 70% of the energy in the power plant's fuel is lost to generation and distribution losses by the time it reaches the end-user...
Perhaps.
But to be fair. Shouldn't one consider that an engine with a more or less constant load is more efficient than one that is continually changing, dur to traffic conditions?
Additionally, you quote that 70% figure as if conventional cars made effective use of 100% of their engine's energy. According to this site
...A Rankine cycle generator, such as a gas turbine, has a typical Carnot efficiency of about 30%, while a diesel or gasoline generator is only about 10-15% efficient in Carnot terms.
Real environmentalist have always pointed out that recycling is their
third choice. Reusing is their second choice. Not requiring the product in the first place is the first choice in a Conserver Society.
Yeah, I noticed this too. The strange thing is that this iteration has already had fifteen times as many comments posted, in just four hours, as the earliear iteration has in four days.
...I've heard some people say it's heat caused by friction resulting from gravitational pressure...
I don't see anyone mentioning friction caused by tidal forces here. But I have read of it being a cause of internal heating.
As I understand it, even a body like our moon, that has one hemisphere constantly facing its primary, will experience heating from friction. The moon's orbit around the Earth is not perfectly circular. So Earth's position in the sky moves a little bit. And the moon's orbit is not directly above the equator, so the Earth's equatorial bulge will result in tidal friction. Plus, the Sun appears to move around the moon's sky, resulting in Tidal Friction.
Phobos and Diemos are much smaller, and less massive, than our moon.
But Mars's orbit is more eccentric than the Earth's.
As I recall, one simplifying assumption Newton made was to do his gravitational calculations as if the heavenly bodies were point-sources. Spherical bodies could be treated like point sources, as the greater force from the near hemisphere was cancelled out by the far hemisphere. But spinning bodies, with equatorial bulges, obviously aren't spherical. So, Tidal Forces can alter a satellite's orbit's eccentricity and the body's period.
It is my understanding that, given enough time, tidal forces would lock all binary systems so they presented the same faces to one another.
...what in the world would an international shuttle standard would have to do with it either way around?
"what in the world?" Well, we are talking about outer space, actually.:-).
Seriously, stupid US budget politics caused the design of the Space Shuttle to be compromised. All space partners suffer because of this.
If the design of the next generation shuttle, used for the international space station, is going to be compromised by stupid budget politics, why shouldn't they be international stupid budget politics?
Anyway, with US short a shuttle, I'd think there should be more of europe stepping up to support the ISS; you know, the *international* space station? of which they are also a part of?
And would you be happy if the ISS partners insisted that the next shuttle be an international effort, built to an international design?
...then it's time to ship some sort of rocket engine up there to move it. In that case we have to question just how much thrust it can structurally take before it breaks into pieces, leaving our engine shooting off into nowhere.
Woops. Consider that the Saturn V could deliver just 49 tons to the Moon's orbit.
The Tunguska object, would have massed more than
500,000 tons -- maybe 5,000,000 tons. The asteroid Apollo, 1.6km in diameter, masses
20 billion tons -- 20,000,000,000 tons. How much power do we need to divert it?
The bottom stage of the Saturn V generates something like 160,000 horsepower, for something like 160 seconds. That is, if my arithmetic is right, something like 10^12 joules.
Of course we couldn't get an intact Saturn V delivered to an approaching asteroid -- not with chemical rockets. The Saturn V could only deposit 50 tons to the Moon's orbit. But suppose we could?
If the asteroid Apollo was going to impact right in the centre of Earth how far in advance would we have to light the candle of this theoretical Saturn V to divert the asteroid enough to miss us?
Kinetic energy == mass * velocity squared / 2
10^12 joules transmitted to 2*10^13 kilograms? If my Physics is not too rusty, will impart a velocity of one twentieth of a meter per second. Five centimetres a second? That is 0.18 km / hour.
At that rate you would have to light the candle on that theoretical Saturn V at least four years before impact to prevent the collision.
To be really safe, because tidal forces would rip the asteroid apart prior to impact. Tidal forces ripped Shoemaker-Levy 9 into fragments. So you would be better served lighting the candle decades in advance.
Now, consider how big a payload could we deliver to a comet or asteroid years or decades in advance? Miniscule.
So, what about using atomic charges? Asteroids might be as fragile as piles of rubble. A single charge might shatter the asteroid, leaving an uncontrollable cloud, still aimed at us like buckshot from a giant shotgun.
Would it matter if the asteroid shattered, if we didn't use one charge, but rather dozens, or hundreds, designed to explode more or less simultaneously? In the sixties there was lipservice paid to using atomic charges for peaceful demolition work here on Earth. The best known plan was to blast a 2nd, sea-level, Panama canal. One of the odd things you learned if you read about this was that if the charges all exploded at once you would get a trench with remarkably straight, even walls.
Or, consider how a shaped charge anti-tank warhead works. The charge is turned into a kind of lense of explosive. The business end has a conical hole carved in it. That cone is coated by a thin layer of copper. When the warhead explodes, the explosion travels through the explosive. When it gets to the apex of the conical hole it begins to focus the metal into a jet. I came across some really cool slow motion pictures of this process -- can't find them now though.
So, what if we landed a network of charges over one hemisphere of the asteroid, and had them go off in a rapid sequence? Could the expanding concussions redirect rubble away from the Earth, leaving a small amount of very rapidly moving small particles going east, and the rest of the asteroid going west, with essentially none coming right at us? If the asteroid shatters, would the overlapping concussions focus the bulk of the rubble in a single direction?
Would charges spread all over the surface of one hemisphere help preserve the structural integrity of asteroid in a way a single charge wouldn't?
This would also indicate that it's time to get together and work up an exception to the "no
nukes in space" treaty.
There are several treaties that would proscribe a single nation from militarizing space with nuclear weapons. One is the 1972 Anti-ballistic missile treaty. George W. Bush has already announced that the USA will no longer abide by this treaty.
But I don't believe any one of those treaties would proscribe a truly international effort.
perhaps explosives could blast it to smithereens, all small enough to burn up in the atmosphere?
IANA physicist, but it seems to me that the parent contribution here, like many contributions in this thread, seriously underestimates the magnitude of the forces we are talking about.
Would the fragments of a demolished asteroid burning up in the atmosphere be significantly less disruptive than having the intact asteroid smash into the Earth? What were the global effects of the dinosaur killer?
It threw up huge amounts of dust? If fragments of the asteroid "burn up in the Earth's atmosphere" will that produce a worse dust problem or a better dust problem than if one big asteroid strikes the surface?
Heat radiation ignited continent wide firestorms? Would a rain of billions of tons of meteors burning up in the atmosphere ignite a firestorm? The Tunguska object (if it existed) was something like 50 to 80 meters in diameter. If I have done my math right, it would have massed something like half a million to a couple of million tons. The dinosaur killer was supposed to be something like 10 to 20 km in diameter, I believe. That would be 10 to 100 trillion tons.
Kinetic energy is, IIRC, one half mass x velocity squared. Earth's escape velocity is 11 kilometres per second. Suppose that was Tunguska's initial velocity? IANA Physicist, but wouldn't a one
kilogram meteor, at 11,000 meters per second, surrender 60,500,000,000,000 Joules? 1.5*10^12 calories? It takes something like 660,000,000 calories to boil a cubic metre of water. And so your one kilogram meteor could boil 23,000 cubic metres of water. If I have done my arithmetic right, Tunguska could have boiled something like several tens of thousands of cubic metres of water. And, the dinosaur killer could have boiled at least 10^17 cubic metres of water. The Earth's atmosphere currently contains
1,290 cubic kilometres of water. A dinosaur killer, that burned up, and surrendered all its energy in the atmosphere, would release enough heat to raise the amount of water vapour in the atmosphere one thousand fold.
Maybe the Earth would be better off if the next dinosaur killer stayed in one piece, and spent some of its energy busting rock?
detect an asteroid the size of Texas headed straight at us?
Just for the record, Texas is 266,807 sq miles. Does it make sense to compare a two dimensional item like a state to a three dimensional object like an asteroid? How? Compare the surface area of the asteroid to Texas?
4 pi r^2 is the formula for the area of a sphere.
Maybe one should use the largest cross section?
This site says Vesta, the third largest asteroid, is the size of the state of Arizona.
This
site and this
site list some of the larger asteroids.
Let me suggest
that the chance of Ceres sneaking up on us is not one in a billion, or one in a trillion. Let me suggest it is zero.
Are there any asteroids the size of US states that haven't been discovered yet? None with Earth crossing orbits.
Are Kuiper Belt Objects asteroids?
If so Ceres is no longer the largest asteroid.
. But it is even more unlikely that something would divert a Ceres size KBO from past the orbit of Pluto to Earth orbit.
How long would it take to divert an asteroid from an Earth impact? Decades? Centuries? Millenia?
Anyhow, Deep Impact had the incoming object be a comet. Even with a project to find deadly NEOs, we could still be snuck up on by a long period or extra-solar comet.
There was a recent article about a similar sized probe, designed solely to inspect satellites for external damage. It will cost $60 millkion a pop.
So I am highly skeptical that these probes, which will include a brand new ion engine, will cost just $30 million.
Actually, since there isn't a 1:1 mapping between Arabic and ASCII...
Good point.
Also worth noting is that "al" is the Arabic equivalent to the English word "the". So a sentence that includes the phrase "the al Queda cells" is redundant.
Algorithm, altitude, alcohol are words English has borrowed from Arabic.
Ken Thompson, of UNIX fame, has an
account of a visit he made to Russia, a few years ago, as an aerospace tourist. I imagined that Tito and Bass were just getting the deluxe version.
I have read elsewhere about space tourism trips where you do everything Thompson does here, plus things like training in the Russian equivalent to NASA's "vomit comet", riding in a centrifuge, plus some of the basic cosmonaut training that Tito got, but no actual flight.
Versions of instant messaging progrmms have beend developed to fulfill
the requirements of investment brokers, who need to have all contact with their clients reliably logged. I read an article about this, about a year ago. IIRC it was a legal requirement, not a "nice to have".
An American spacecraft breaks in LEO. The can't initiate re-entry.
Big rush-rush at Kennedy to ready a rescue mission.
But it looks like all is in vain, bad weather prevents the launch.
However, a plucky cosmonaut passes by, just in time, and silently tosses them some extra oxygen.
At the time the Russians and the Americans couldn't dock with one another.
My recollection is that Nixon and Breshnev, or reasonable equivalent, discussed the film, and not-only agreed on the 1975 Apollo-Soyuz mission mentioned on the movie's web-site, but that they also agreed to co-operate to retain the ability to dock with one another's vessels.
The reentry path is already optomized to minimize heat loads on the vehicle. It cannot be optimized more to lessen the heat...
Is it possible to choose a different reentry scheme when you suspect the orbiter has sustained life-threatening damage?
Just because I heard some guy on TV assert this doesn't make it true. But you seem to be dismissing the idea too easily.
IIRC he said the current reentry program is optomized land the orbiter in a way that prevents as much wear and tear on the shuttle as possible.
He suggested that if someone in authority had decided that the orbiter had passed some damage threshold that it presented too much danger to the crew to follow the standard program, then it should follow a program that designed to try to preserve the lives of the crew, even if it ruined the shuttle.
The standard program was designed to equalize the wear and tear on the two wings. As the left wing slowly started to fail, it experienced more drag. Uncorrected, this would have made it trail the right hand wing, subjecting it to more than its share of friction.
Under the standard program, this was a condition that needed to be corrected. The orbiter first used its elevons to shove that lazy left hand wing back to receive an equal share of friction. And when that didn't prove sufficient, the orbiter used its maneuvering and orientation jets.
In retrospect, let me suggest, this was a mistake.
Let me suggest there is an envelope of stability for the shuttles orientations. The talking head on the TV suggested it would be possible for the shuttle to enter in a slightly skewed orientation that favoured the left wing and had more stress put on the undamaged right wing.
We don't know how badly damaged the wing was. We don't know whether this would have saved the crew. In retrospect, wouldn't it have been worth trying?
I heard someone talking about the tiles, and "soak-through". If I understood him properly the tiles are rated to protect the underlying skin of the shuttle from the heat of re-entry for a specific maximum duration. If I understood him properly a re-entry prolonged beyond this point would allow heat to soak through to the aluminum, eventually damaging it. I think he said this damage would occur after the shuttle landed.
Well shit, that would have been worth it, wouldn't it? Maybe you could spray the tiles with fire hoses, to cool them off, even if heat shock made them shatter. If the underlying structural elements don't warp too much, you can always glue on another $100,000,000 worth of tiles.
No, we don't know if this would have helped. We don't even know, for sure, why the orbiter failed. But, I hope that if they don't abandon the shuttles, they change the rules to allow for emergency re-entry programs.
With the puny processing power of the time it didn't seem feasible to have a sensor for each tile. But wouldn't it be possible today?
If the Progress could be given enough fuel
to reach the orbiter, they could not have used the arm
to grapple it, or to ditch the science modules. They didn't
anticipate needing the arm, so, just like the docking rings,
they didn't mount it this time around.
It was at a lab in Southern Ontario, getting preventive
maintenance.
I think I prefer this Soviet design, the MAKS (Multipurpose Access System), a little brother of Buran. The orbiter and external tank ride to a launch height of 9,000 meters on top of a big cargo plane -- similar to the 747 used to fly the American shuttle from the landing site back to Kennedy.
A google search for spaceplane turns up lots of articles. Another slashdot reader already recommended
Gregg Easterbrook's 1980 article on Columbia's first launch. I guess one lesson from looking back on it is to take the claims of the designers with considerable skepticism. Fity or more launches per year? Cost a third or less per ton of the cost of single shot rockets? Ha.
Yet, I would guess that the general public was seeing the American shuttle as being a big success. I expect people will see it as a success again.
I like the idea of putting aerospace workers from the former Soviet Union to work. I like the idea of putting them to useful, peaceful, dignified work. I don't like the idea of them being owed six months of paltry back-pay. Not when some of them have skills developing WoMD.
I like Dennis Tito's answer to one of the questions he was asked when he returned from being the world's first space tourist. He was asked whether it was frivilous to spend $20,000,000 on a vacation, when the world faced terrible problems, like grinding poverty. He said something like:
You are correct. That money should have been spent helping the poor. And it was. Do you know the average wage of a Russian aerospace worker? About $100 per month.
I read an
article some time ago, by a tourist, who knew something about aerospace, who dropped by the Buran that was being turned into a cafe, in Gorky Park, while it was still being converted. The security guard who stopped him, was quite knowledgeable -- because he was a former aerospace worker who had worked on Buran. This seemed like a terrible coincidence at first, a terribly ironic one.
But then it turned out that the Buran cafe project was a project of the former Buran workers. They were all involved.
I couldn't help really feeling for these men and women. I imagined they had traded back-pay they were never likely to see for the Buran mockup they were turning in to a cafe. (Cafe patrons were going to get to order real cosmonaut space rations.) But they hadn't given up. They hadn't given up on aerospace. They hadn't given up their dignity. They hadn't given up on peace. They hadn't given up on their country.
The Soviet Union had a space program any former citizen could be proud of. I'd like to see their talents put to use. This isn't charity. They were talented.
Plus, there is the peace factor. Everyone is worried that "rogue states" are going to acquire weapons of mass destruction by subverting penniless former defense workers from the former Scviet Union. Well, why don't we address this issue by making sure they weren't left penniless?
Yes, I know organized crime is (was?) a terrible problem throughout the former Soviet Union.
Still, would the dollars, yen, euros of the international community be better spent in the former Soviet Union, where paying an aerospace worker $1000 a month would be a ten-fold pay increase, then in, let's say, the USA.
The USA, or more precisely, the US aerospace industry, is the land of the $1000 spanner. Let's be honest. That too, is a kind of corruption.
The US's milltary-industrial complex built many weaspons systems over the years. Do you know which one provided the greatest invulnerability?
That would have to be the one with a sub-contractor in every congressional district.
I think I read about this incident in a discussion of the Airbus 320.
The Airbus 320 was more heavily fly-by-wire than comparable American airliners.
In traditional airplanes, the pilot moves the stick, and his other controls, and there is a mechanical connection between his movement and the planes rudder, throttle and aelerons. Not so with the airbus.
A computer system interprets the pilots commands, and controls the
flight surfaces itself.
As of the time of this discussion (about 12 or more years ago) the airbus was programmed to over-ride any pilot who requested a maneuver that would cause the plane to pull more than 2.5 Gs.
Someone had cited an incident when an airliner, out of Hawaii, had experienced a problem that put it into a steep dive. The pilot and co-pilot recovered control and pulled back on the stick, just in time to save it from going into the drink. The plane returned to Hawaii.
An examination of the airframe determined that this plane should never
fly again. Analysis of the warped beams and stretched rivet holes determined that the plane had experienced over 4.5 Gs.
I believe the plane in question was a 747.
My point? This story makes me doubt 3 Gs would rip the wings off of a modern airliner.
Sigh. That was a still from 2001. Dave has just rushed out in his little space pod to try to save Frank, the other astronaut. HAL,
the psychotic computer, has killed him.
HAL refuses Dave's request to open the pod bay doors. "I am afraid I really can't do that Dave."
Dave says he will enter using the manual airlock.
HAL replies, that Dave will find that difficult without his space-suit helmet.
Dave positions the pod's door above the open airlock door. Takes a couple of deep breaths, and blows the explosive bolts.
Air pressure blows him into the airlock. He closes the door, and hits
the button to fill the lock with air.
...Columbia was the only shuttle in the fleet that did NOT have a docking port that was compatible with the ISS. So... I guess there was truly no reason to check. They can't fix the tile and have no way to transfer to the ISS. So it truly didn't matter.
Slashdot Mirror
Actually, I think the article says the Russian Enterprise module is capable of docking two Soyuz capsules, each of which can evacuate six crew members, for a total of six.
The ISS only bear three permanent crew members, between shuttle flights, now, because that is the total number that can be evacuated by the single Soyuz it has mounted now.
The Soyuz are replaced every six months. There was recent talk of building more Apollo capsules, if the Russians can't afford to build more Soyuz. A recent American law prevents them from paying for Russian Soyuz.
Perhaps.
But to be fair. Shouldn't one consider that an engine with a more or less constant load is more efficient than one that is continually changing, dur to traffic conditions?
Additionally, you quote that 70% figure as if conventional cars made effective use of 100% of their engine's energy. According to this site
Real environmentalist have always pointed out that recycling is their third choice. Reusing is their second choice. Not requiring the product in the first place is the first choice in a Conserver Society.
Extra chromosomes?
Speak for yourself! I am making use of all of mine, thank you very much.
Yeah, I noticed this too. The strange thing is that this iteration has already had fifteen times as many comments posted, in just four hours, as the earliear iteration has in four days.
I don't see anyone mentioning friction caused by tidal forces here. But I have read of it being a cause of internal heating.
As I understand it, even a body like our moon, that has one hemisphere constantly facing its primary, will experience heating from friction. The moon's orbit around the Earth is not perfectly circular. So Earth's position in the sky moves a little bit. And the moon's orbit is not directly above the equator, so the Earth's equatorial bulge will result in tidal friction. Plus, the Sun appears to move around the moon's sky, resulting in Tidal Friction.
Phobos and Diemos are much smaller, and less massive, than our moon. But Mars's orbit is more eccentric than the Earth's.
As I recall, one simplifying assumption Newton made was to do his gravitational calculations as if the heavenly bodies were point-sources. Spherical bodies could be treated like point sources, as the greater force from the near hemisphere was cancelled out by the far hemisphere. But spinning bodies, with equatorial bulges, obviously aren't spherical. So, Tidal Forces can alter a satellite's orbit's eccentricity and the body's period.
It is my understanding that, given enough time, tidal forces would lock all binary systems so they presented the same faces to one another.
Ignore the grumpy posts, this is an interesting article.
Maybe they used aerogel?
"what in the world?" Well, we are talking about outer space, actually. :-).
Seriously, stupid US budget politics caused the design of the Space Shuttle to be compromised. All space partners suffer because of this.
If the design of the next generation shuttle, used for the international space station, is going to be compromised by stupid budget politics, why shouldn't they be international stupid budget politics?
And would you be happy if the ISS partners insisted that the next shuttle be an international effort, built to an international design?
Woops. Consider that the Saturn V could deliver just 49 tons to the Moon's orbit.
The Tunguska object, would have massed more than 500,000 tons -- maybe 5,000,000 tons. The asteroid Apollo, 1.6km in diameter, masses 20 billion tons -- 20,000,000,000 tons . How much power do we need to divert it?
The bottom stage of the Saturn V generates something like 160,000 horsepower, for something like 160 seconds. That is, if my arithmetic is right, something like 10^12 joules. Of course we couldn't get an intact Saturn V delivered to an approaching asteroid -- not with chemical rockets. The Saturn V could only deposit 50 tons to the Moon's orbit. But suppose we could? If the asteroid Apollo was going to impact right in the centre of Earth how far in advance would we have to light the candle of this theoretical Saturn V to divert the asteroid enough to miss us?
Kinetic energy == mass * velocity squared / 2
10^12 joules transmitted to 2*10^13 kilograms? If my Physics is not too rusty, will impart a velocity of one twentieth of a meter per second. Five centimetres a second? That is 0.18 km / hour.
At that rate you would have to light the candle on that theoretical Saturn V at least four years before impact to prevent the collision.
To be really safe, because tidal forces would rip the asteroid apart prior to impact. Tidal forces ripped Shoemaker-Levy 9 into fragments. So you would be better served lighting the candle decades in advance.
Now, consider how big a payload could we deliver to a comet or asteroid years or decades in advance? Miniscule.
So, what about using atomic charges? Asteroids might be as fragile as piles of rubble. A single charge might shatter the asteroid, leaving an uncontrollable cloud, still aimed at us like buckshot from a giant shotgun.
Would it matter if the asteroid shattered, if we didn't use one charge, but rather dozens, or hundreds, designed to explode more or less simultaneously? In the sixties there was lipservice paid to using atomic charges for peaceful demolition work here on Earth. The best known plan was to blast a 2nd, sea-level, Panama canal. One of the odd things you learned if you read about this was that if the charges all exploded at once you would get a trench with remarkably straight, even walls.
Or, consider how a shaped charge anti-tank warhead works. The charge is turned into a kind of lense of explosive. The business end has a conical hole carved in it. That cone is coated by a thin layer of copper. When the warhead explodes, the explosion travels through the explosive. When it gets to the apex of the conical hole it begins to focus the metal into a jet. I came across some really cool slow motion pictures of this process -- can't find them now though.
So, what if we landed a network of charges over one hemisphere of the asteroid, and had them go off in a rapid sequence? Could the expanding concussions redirect rubble away from the Earth, leaving a small amount of very rapidly moving small particles going east, and the rest of the asteroid going west, with essentially none coming right at us? If the asteroid shatters, would the overlapping concussions focus the bulk of the rubble in a single direction? Would charges spread all over the surface of one hemisphere help preserve the structural integrity of asteroid in a way a single charge wouldn't?
There are several treaties that would proscribe a single nation from militarizing space with nuclear weapons. One is the 1972 Anti-ballistic missile treaty. George W. Bush has already announced that the USA will no longer abide by this treaty.
But I don't believe any one of those treaties would proscribe a truly international effort.
IANA physicist, but it seems to me that the parent contribution here, like many contributions in this thread, seriously underestimates the magnitude of the forces we are talking about.
Would the fragments of a demolished asteroid burning up in the atmosphere be significantly less disruptive than having the intact asteroid smash into the Earth? What were the global effects of the dinosaur killer?
It threw up huge amounts of dust? If fragments of the asteroid "burn up in the Earth's atmosphere" will that produce a worse dust problem or a better dust problem than if one big asteroid strikes the surface?
Heat radiation ignited continent wide firestorms? Would a rain of billions of tons of meteors burning up in the atmosphere ignite a firestorm? The Tunguska object ( if it existed ) was something like 50 to 80 meters in diameter. If I have done my math right, it would have massed something like half a million to a couple of million tons. The dinosaur killer was supposed to be something like 10 to 20 km in diameter, I believe. That would be 10 to 100 trillion tons.
Kinetic energy is, IIRC, one half mass x velocity squared. Earth's escape velocity is 11 kilometres per second. Suppose that was Tunguska's initial velocity? IANA Physicist, but wouldn't a one kilogram meteor, at 11,000 meters per second, surrender 60,500,000,000,000 Joules? 1.5*10^12 calories? It takes something like 660,000,000 calories to boil a cubic metre of water. And so your one kilogram meteor could boil 23,000 cubic metres of water. If I have done my arithmetic right, Tunguska could have boiled something like several tens of thousands of cubic metres of water. And, the dinosaur killer could have boiled at least 10^17 cubic metres of water. The Earth's atmosphere currently contains 1,290 cubic kilometres of water . A dinosaur killer, that burned up, and surrendered all its energy in the atmosphere, would release enough heat to raise the amount of water vapour in the atmosphere one thousand fold.
Maybe the Earth would be better off if the next dinosaur killer stayed in one piece, and spent some of its energy busting rock?
Just for the record, Texas is 266,807 sq miles . Does it make sense to compare a two dimensional item like a state to a three dimensional object like an asteroid? How? Compare the surface area of the asteroid to Texas? 4 pi r^2 is the formula for the area of a sphere.
Maybe one should use the largest cross section? This site says Vesta , the third largest asteroid, is the size of the state of Arizona. This site and this site list some of the larger asteroids.
Let me suggest that the chance of Ceres sneaking up on us is not one in a billion, or one in a trillion. Let me suggest it is zero.
Are there any asteroids the size of US states that haven't been discovered yet? None with Earth crossing orbits.
Are Kuiper Belt Objects asteroids? If so Ceres is no longer the largest asteroid. . But it is even more unlikely that something would divert a Ceres size KBO from past the orbit of Pluto to Earth orbit.
How long would it take to divert an asteroid from an Earth impact? Decades? Centuries? Millenia? Anyhow, Deep Impact had the incoming object be a comet. Even with a project to find deadly NEOs, we could still be snuck up on by a long period or extra-solar comet.
There was a recent article about a similar sized probe, designed solely to inspect satellites for external damage. It will cost $60 millkion a pop. So I am highly skeptical that these probes, which will include a brand new ion engine, will cost just $30 million.
Good point.
Also worth noting is that "al" is the Arabic equivalent to the English word "the". So a sentence that includes the phrase "the al Queda cells" is redundant.
Algorithm, altitude, alcohol are words English has borrowed from Arabic.
I have read elsewhere about space tourism trips where you do everything Thompson does here, plus things like training in the Russian equivalent to NASA's "vomit comet", riding in a centrifuge, plus some of the basic cosmonaut training that Tito got, but no actual flight.
Versions of instant messaging progrmms have beend developed to fulfill the requirements of investment brokers, who need to have all contact with their clients reliably logged. I read an article about this, about a year ago. IIRC it was a legal requirement, not a "nice to have".
An American spacecraft breaks in LEO. The can't initiate re-entry. Big rush-rush at Kennedy to ready a rescue mission. But it looks like all is in vain, bad weather prevents the launch. However, a plucky cosmonaut passes by, just in time, and silently tosses them some extra oxygen.
At the time the Russians and the Americans couldn't dock with one another.
My recollection is that Nixon and Breshnev, or reasonable equivalent, discussed the film, and not-only agreed on the 1975 Apollo-Soyuz mission mentioned on the movie's web-site, but that they also agreed to co-operate to retain the ability to dock with one another's vessels.
So, are you sure the Soviets stole the design?
Is it possible to choose a different reentry scheme when you suspect the orbiter has sustained life-threatening damage?
Just because I heard some guy on TV assert this doesn't make it true. But you seem to be dismissing the idea too easily.
IIRC he said the current reentry program is optomized land the orbiter in a way that prevents as much wear and tear on the shuttle as possible.
He suggested that if someone in authority had decided that the orbiter had passed some damage threshold that it presented too much danger to the crew to follow the standard program, then it should follow a program that designed to try to preserve the lives of the crew, even if it ruined the shuttle.
The standard program was designed to equalize the wear and tear on the two wings. As the left wing slowly started to fail, it experienced more drag. Uncorrected, this would have made it trail the right hand wing, subjecting it to more than its share of friction. Under the standard program, this was a condition that needed to be corrected. The orbiter first used its elevons to shove that lazy left hand wing back to receive an equal share of friction. And when that didn't prove sufficient, the orbiter used its maneuvering and orientation jets.
In retrospect, let me suggest, this was a mistake.
Let me suggest there is an envelope of stability for the shuttles orientations. The talking head on the TV suggested it would be possible for the shuttle to enter in a slightly skewed orientation that favoured the left wing and had more stress put on the undamaged right wing.
We don't know how badly damaged the wing was. We don't know whether this would have saved the crew. In retrospect, wouldn't it have been worth trying?
I heard someone talking about the tiles, and "soak-through". If I understood him properly the tiles are rated to protect the underlying skin of the shuttle from the heat of re-entry for a specific maximum duration. If I understood him properly a re-entry prolonged beyond this point would allow heat to soak through to the aluminum, eventually damaging it. I think he said this damage would occur after the shuttle landed.
Well shit, that would have been worth it, wouldn't it? Maybe you could spray the tiles with fire hoses, to cool them off, even if heat shock made them shatter. If the underlying structural elements don't warp too much, you can always glue on another $100,000,000 worth of tiles.
No, we don't know if this would have helped. We don't even know, for sure, why the orbiter failed. But, I hope that if they don't abandon the shuttles, they change the rules to allow for emergency re-entry programs.
With the puny processing power of the time it didn't seem feasible to have a sensor for each tile. But wouldn't it be possible today?
It was at a lab in Southern Ontario, getting preventive maintenance.
A google search for spaceplane turns up lots of articles. Another slashdot reader already recommended Gregg Easterbrook's 1980 article on Columbia's first launch. I guess one lesson from looking back on it is to take the claims of the designers with considerable skepticism. Fity or more launches per year? Cost a third or less per ton of the cost of single shot rockets? Ha.
Yet, I would guess that the general public was seeing the American shuttle as being a big success. I expect people will see it as a success again.
I like the idea of putting aerospace workers from the former Soviet Union to work. I like the idea of putting them to useful, peaceful, dignified work. I don't like the idea of them being owed six months of paltry back-pay. Not when some of them have skills developing WoMD.
I like Dennis Tito's answer to one of the questions he was asked when he returned from being the world's first space tourist. He was asked whether it was frivilous to spend $20,000,000 on a vacation, when the world faced terrible problems, like grinding poverty. He said something like:
I read an article some time ago, by a tourist, who knew something about aerospace, who dropped by the Buran that was being turned into a cafe, in Gorky Park, while it was still being converted. The security guard who stopped him, was quite knowledgeable -- because he was a former aerospace worker who had worked on Buran. This seemed like a terrible coincidence at first, a terribly ironic one.But then it turned out that the Buran cafe project was a project of the former Buran workers. They were all involved.
I couldn't help really feeling for these men and women. I imagined they had traded back-pay they were never likely to see for the Buran mockup they were turning in to a cafe. (Cafe patrons were going to get to order real cosmonaut space rations.) But they hadn't given up. They hadn't given up on aerospace. They hadn't given up their dignity. They hadn't given up on peace. They hadn't given up on their country.
The Soviet Union had a space program any former citizen could be proud of. I'd like to see their talents put to use. This isn't charity. They were talented.
Plus, there is the peace factor. Everyone is worried that "rogue states" are going to acquire weapons of mass destruction by subverting penniless former defense workers from the former Scviet Union. Well, why don't we address this issue by making sure they weren't left penniless?
Yes, I know organized crime is (was?) a terrible problem throughout the former Soviet Union.
Still, would the dollars, yen, euros of the international community be better spent in the former Soviet Union, where paying an aerospace worker $1000 a month would be a ten-fold pay increase, then in, let's say, the USA.
The USA, or more precisely, the US aerospace industry, is the land of the $1000 spanner. Let's be honest. That too, is a kind of corruption.
The US's milltary-industrial complex built many weaspons systems over the years. Do you know which one provided the greatest invulnerability?
That would have to be the one with a sub-contractor in every congressional district.
In traditional airplanes, the pilot moves the stick, and his other controls, and there is a mechanical connection between his movement and the planes rudder, throttle and aelerons. Not so with the airbus. A computer system interprets the pilots commands, and controls the flight surfaces itself.
As of the time of this discussion (about 12 or more years ago) the airbus was programmed to over-ride any pilot who requested a maneuver that would cause the plane to pull more than 2.5 Gs.
Someone had cited an incident when an airliner, out of Hawaii, had experienced a problem that put it into a steep dive. The pilot and co-pilot recovered control and pulled back on the stick, just in time to save it from going into the drink. The plane returned to Hawaii. An examination of the airframe determined that this plane should never fly again. Analysis of the warped beams and stretched rivet holes determined that the plane had experienced over 4.5 Gs.
I believe the plane in question was a 747.
My point? This story makes me doubt 3 Gs would rip the wings off of a modern airliner.
HAL refuses Dave's request to open the pod bay doors. "I am afraid I really can't do that Dave."
Dave says he will enter using the manual airlock.
HAL replies, that Dave will find that difficult without his space-suit helmet.
Dave positions the pod's door above the open airlock door. Takes a couple of deep breaths, and blows the explosive bolts.
Air pressure blows him into the airlock. He closes the door, and hits the button to fill the lock with air.
That is what HAL thought