If launch becomes less expensive - then design margins widen, you can make stuff heavier, incorporate more spare subsystems, launch more consumables,... all in the same budget.
You do not simply design the same way, and fly exactly the same hardware.
With launch costs at under a tenth of current ones, if you can't work out how to do space more cheaply, you need to get out of the way.
Much of the expense comes from lightening everything.
The 'shirt sleeve' environment of pressurised craft is in many ways pretty similar to earth. Unless fluids or convection is involved - stuff tends to 'just work'. You may need to add fans, but the modifications required are small. If a kilo of wasted mass costs you not $10K, but $1K - suddenly a _lot_ of the time it becomes much cheaper to buy a commercial part, and test it, rather than spending $20K to design a fresh part - where that is sensible if you've got only one launch opportunity in the budget, and you're screwed if it doesn't work.
"On the other hand, the Falcon Heavy has a fraction of the capabilities of the Shuttle. It has no ability to return payloads. It has no ability to launch operators and payloads on the same flight. It requires the payloads to provide all of their own support. Etc... Etc..." This is of course true. However.
This is arguing that you need a helicopter to compete in construction, you can't make do with much cheaper trucks.
Technically the shuttle is more flexible. If, two people offer to build you a house - one has a helicopter, one has a truck - are you going to pick the one that ends up with the house needing to be custom-made out of lightweight materials at vast cost...
By doing things differently. If someone has been making very nice engraved wooden boxes to sell cheese in - at the lowest possible price - that doesn't mean that if someone else starts selling cheese in plastic bags, that the consumer suffers in any way, or that the cheese is unsafe.
The two things 'only three organisations' and 'humans can't do it' - are completely unrelated. Nobody is trying to fly rockets up by hand - it's completely insane.
The computations used for docking are not the hard part. The fine control, implementation of the guidance sensors, reliability of the rocket, able to perform reliably are the hard part.
Space launch has cost $10K/lb or so since 1960. This isn't a law of physics. NASA has systematically proved incapable of lowering launch cost - their primary contractors have no interest in doing this, and they are biased to 'clever' rather than 'workable' solutions. And then there is the problem that NASA has to spend money politically, not efficiently. It's largely a welfare organisation for aerospace - it's not a space organisation.
One of the last attempts at lowering launch costs - X33 - had three separate untried technologies on it.
SpaceX is taking a rather different tack - using shiny stuff only when it has a major benefit.
Their next rocket is planned to come in at around $1K/lb. And they're thinking of reusability, to lower the costs to well below this. Fuel costs are around $5/lb.
The space program isn't pathetic because of the lack of money being spent on it. If you take the funding from SLS, up to the first couple of launches, and use it to buy commercial launches on SpaceX - you get comfortably enough launch to lift the USS Iowa - closing on 200 times the mass of ISS.
And this assumes that SpaceX can't get reusability working. If they can, then multiply these numbers by a _large_ number.
There is almost certainly enough margin for a little leeway either way.
For an initial launch - you want to remove all of the possible variables you can, and have as much margin as possible.
Once you're a dozen launches in, and have a good handle on what the actual operational performance is, then the launch window can stretch out and use a little bit of the margin.
If, for example a 3 minute window lets you launch rather than wait for next time, that can be worth spending some of your margin on. Margin is there to be spent prudently to reduce costs and increase overall system reliability.
Well... That's fun and all - but it's quite, quite irrelevant. For some time now, we've had the solution to the problem - calculus. The maths involved would not tax Newton greatly.
Humans suck at intuitively understanding and controlling stuff outside narrow realms of experience and reaction time.
This is why we use maths to do it for us. From calculating loads on a bridge, to working out the cost of an order - you don't just randomly guess on the basis of experience, unless it's very uncritical.
The mathematics involved in the rendevous is not complex to understand. It's moderately annoying to execute, but it's not more than a dozen or two lines of code to work out the approximate trajectory.
Working out the exact optimum trajectory is rather harder, but it's not the hard bit of rocketry.
I believe I may have misremembered what I believe was a WHO paper on this. http://ije.oxfordjournals.org/content/39/4/1064.full - for example - gives the figure as 20* more risky for anal than vaginal sex - 30* with the figures given seems entirely plausible for a study to have found, and for me to have remembered.
Your case raises the interesting issue of transmissibility.
It's been found through studies of cases like yours that 'vanilla' couples sex, where the partners are otherwise healthy apart from one being HIV+ have well under a percent (.3% IIRC) rate per act of transmitting HIV. For anal, this rises to 30%.
The reproductive system - in the absence of sores or other problems due to other diseases - is remarkably good at protecting itself from disease.
"With EMP bomb, unlike a nuke, you don't waste energy to generate EMR in all the spectrum, with all the unneeded parts like visible light, IR and UV, and heat up surroundings to rather uncomfortable temperatures." - technically true, but somewhat misleading.
Around 0.1% of energy goes into EMP. For a ten kiloton device, this is still the equivalent of 10 tons of explosive - in EMP. But - a flux-compression-generator converts about a third of the energy into electricity, and then you get about half from the transmitter, if lucky.
So, to get the equivalent EMP to a 10 kiloton nuclear device, you need of the order of 60 tons of explosives alone. The generator is likely to double that, and the transmission antenna and magnetrons (which have to be physically large so they don't just arc across) double it again.
So, of the order of 250 tons. This is 'problematic' to get to a high altitude, where it needs to be, to have more than a local effect. I note 10 25 ton truck bombs are going to be able to wreck large portions of most financial districts, and be considerably cheaper.
'terrorist' EMP weapons with more than a local (building or three) scale are fantasy.
Consider what tiny, tiny, tiny fraction of a percent they'd have to drop CPU load in every copy of windows, in order to equal the trivial saving they are attempting to make.
Assuming they are incompetent. For example, the 'microsoft update' scheme is as I understand it run on an unencrypted protocol. There would be nothing stopping office telling the update client to send a few bytes of data along with that stream.
This is not also - technically - an extremely complex and involved project. It's conceptually rather simple. A drawstring bag, a couple of solar panels - some ion thrusters, a fairly standard reaction control system.
None of these are inherently very expensive, compared to the purported 2 billion price tag.
In some ways, the potential for cost-saving between doing it the NASA way, and sanely is higher than it is for a comparatively complex device that has to undergo high stress, and work 100% of the time like a rocket.
For 99.99% of the mission - a random reset, and wait for commands from earth will do nothing to substantially delay or endanger the mission.
This is very different from the case of a rocket. There is time to think, and to bring up second-string hardware to take over tasks.
Firstly, I'm extremely skeptical of one of the conclusions - 'flash will make a CRT monitor use more power' - which I just don't believe - it will use an amount of power dependent on the average screen brightness - which may be an increase over black. LCDs are different - the panel does actually take some energy to change state, and the lag compensation circuitry will use more in motion.
Secondly - a huge part has been missed out of this. Power consumption of the computer.
Flash, or javascript, even in the background, can considerably increase power. For example, I just closed all of the flash/animated things in the background on other tabs in firefox, and the CPU usage is now bouncing around 2%, with the computer using 17W. If I start up a new tab with some flash, and gif animations, it goes up to 25W. (+8W) Even switching away from the tab only takes it to 23W or so. (+5W)
It would be interesting to work out the total electricity wasted by common flash ads.
To a degree. It's more complex than this. Mainstream computers basically assume error-free operation - because it's cheaper to run the devices a little slower - or to use more area or... than to add the extra complexity required for error tolerant computing. You can construct computers with gates that are 99% reliable quite easily. 90% requires a lot more check logic. By the time you hit something like 66%, the design is many times the size of the 'error free' one.
BBSs would clearly not have won. The more likely winner would have been AOL, compuserv,... or a conglomeration of several of these providers with interoperability between them.
Once you get enough 'bums on seats' - there is a network effect - why would someone get on the internet when it had fewer sites?
There seems to be a general assumption by many that the internet was predestined to win out over these other pre-existing nets.
It wasn't. Things like the much derided Al Gore 'invention of the internet' - he was instrumental in securing some funding for non-educational use.
If the existing services that were taking off when the internet came along from behind had gotten their acts together - and gotten for example inter-provider mail working, the internet in its present form may not have happened.
It could so easily have been that if you wanted to make a page to advertise your business, it wasn't a case of simply sign up to one of the many thousands of hosting providers - but three or four large companies dominate.
You need some science background - if you don't know what a harmonic is, or a power spectra - you'll be pretty lost.
But as it's a new field, I was able to keep up with about 80% of the content, even though I only have a couple of semesters of physics under my belt, and a very limited understanding of the maths.
Not quite. Kepler was designed to detect earth-like planets. It does this by detecting the dimming of the star when a planet passes in front of it. Unfortunately, the sun has turned out to not be very typical. Most stars are much more flickery than the sun - which we diddn't realise until Kepler.
This means that it's quite hard to pick up an earth-like planet in an earth-like orbit crossing the star. Both larger planets - they obscure more of the star, so are more visible, and closer in - they orbit much more rapidly, so you can add up the crossings) are significantly easier to detect.
The extended mission would get Kepler about to its initial mission goals - in the face of stars turning out to be more twinkly than expected. Detecting reliably earth-like planets around candidate stars.
It will coincidentally allow the detection of more very distant large planets, and close-in very small planets.
The fundamental problem with microwaves is - they're microwaves. They are just another sort of radio, and like all radio waves, and light, and... - they undergo diffraction.
This limits how much you can focus them.
A 'small' transmitter antenna of say 1km, with microwaves of about 10cm wavelength, will have a beamwidth of about: 1.22*.1m / 1000m. This is a beam which spreads about one part in ten thousand.
After 10000km, the beam will be one kilometer in diameter. At the distance of the moon - 40km.
So, you need an antenna 4km in diameter on your craft simply to pick up one percent of the beam at the moon.
Range is a major problem.
Lasers work somewhat better - but have their own annoying issues.
An advanced ion thruster may use nearly 1/50th of the fuel of a conventional rocket engine. But, it needs 50 times the power to do this.
So, to replace a conventional rocket engine burning a kilo of fuel a second, and producing a thrust of perhaps 500kg, with no electrical requirements, you need about 20 grams of fuel a second, and around 450 megawatts of power.
Needless to say - for many applications, the power plant ends up heavier than the engine it's replacing.
It only works in very low thrust applications.
The low thrust also brings other problems. For example, around the earth is a belt of charged particles. Ascending through these on conventional rockets is not a problem. You do it so rapidly.
With ion engines, you need to slowly spiral out (due to being power limited), and your whole craft gets highly irradiated.
Slashdot Mirror
Of course, that should read mm/s.
Slow and gentle.
Press on a thousand pounds in freefall with a force of a pound, and in ten seconds, it's moving at 10cm/s.
This is probably faster than you want in a confined environment.
If you need more than your little finger to exert the pressure - you're doing it wrong.
If launch becomes less expensive - then design margins widen, you can make stuff heavier, incorporate more spare subsystems, launch more consumables, ... all in the same budget.
You do not simply design the same way, and fly exactly the same hardware.
With launch costs at under a tenth of current ones, if you can't work out how to do space more cheaply, you need to get out of the way.
Much of the expense comes from lightening everything.
The 'shirt sleeve' environment of pressurised craft is in many ways pretty similar to earth.
Unless fluids or convection is involved - stuff tends to 'just work'.
You may need to add fans, but the modifications required are small.
If a kilo of wasted mass costs you not $10K, but $1K - suddenly a _lot_ of the time it becomes much cheaper to buy a commercial part, and test it, rather than spending $20K to design a fresh part - where that is sensible if you've got only one launch opportunity in the budget, and you're screwed if it doesn't work.
"On the other hand, the Falcon Heavy has a fraction of the capabilities of the Shuttle. It has no ability to return payloads. It has no ability to launch operators and payloads on the same flight. It requires the payloads to provide all of their own support. Etc... Etc..."
This is of course true.
However.
This is arguing that you need a helicopter to compete in construction, you can't make do with much cheaper trucks.
Technically the shuttle is more flexible.
If, two people offer to build you a house - one has a helicopter, one has a truck - are you going to pick the one that ends up with the house needing to be custom-made out of lightweight materials at vast cost...
Is around a gigabyte per second.
(100 packs of 16*64GB microSDs, in appropriate packaging, swallowed at intervals over the course of a day)
By doing things differently.
If someone has been making very nice engraved wooden boxes to sell cheese in - at the lowest possible price - that doesn't mean that if someone else starts selling cheese in plastic bags, that the consumer suffers in any way, or that the cheese is unsafe.
The two things 'only three organisations' and 'humans can't do it' - are completely unrelated.
Nobody is trying to fly rockets up by hand - it's completely insane.
The computations used for docking are not the hard part.
The fine control, implementation of the guidance sensors, reliability of the rocket, able to perform reliably are the hard part.
Space launch has cost $10K/lb or so since 1960.
This isn't a law of physics.
NASA has systematically proved incapable of lowering launch cost - their primary contractors have no interest in doing this, and they are biased to 'clever' rather than 'workable' solutions. And then there is the problem that NASA has to spend money politically, not efficiently. It's largely a welfare organisation for aerospace - it's not a space organisation.
One of the last attempts at lowering launch costs - X33 - had three separate untried technologies on it.
SpaceX is taking a rather different tack - using shiny stuff only when it has a major benefit.
Their next rocket is planned to come in at around $1K/lb.
And they're thinking of reusability, to lower the costs to well below this.
Fuel costs are around $5/lb.
http://www.spacex.com/multimedia/videos.php - this is a cool video on their reusable design.
And this is a picture of the hardware - the foldable landing legs for the first stage of the Falcon 9.
http://img.ly/i5JQ
The space program isn't pathetic because of the lack of money being spent on it.
If you take the funding from SLS, up to the first couple of launches, and use it to buy commercial launches on SpaceX - you get comfortably enough launch to lift the USS Iowa - closing on 200 times the mass of ISS.
And this assumes that SpaceX can't get reusability working.
If they can, then multiply these numbers by a _large_ number.
There is almost certainly enough margin for a little leeway either way.
For an initial launch - you want to remove all of the possible variables you can, and have as much margin as possible.
Once you're a dozen launches in, and have a good handle on what the actual operational performance is, then the launch window can stretch out and use a little bit of the margin.
If, for example a 3 minute window lets you launch rather than wait for next time, that can be worth spending some of your margin on.
Margin is there to be spent prudently to reduce costs and increase overall system reliability.
Well...
That's fun and all - but it's quite, quite irrelevant.
For some time now, we've had the solution to the problem - calculus.
The maths involved would not tax Newton greatly.
Humans suck at intuitively understanding and controlling stuff outside narrow realms of experience and reaction time.
This is why we use maths to do it for us.
From calculating loads on a bridge, to working out the cost of an order - you don't just randomly guess on the basis of experience, unless it's very uncritical.
The mathematics involved in the rendevous is not complex to understand.
It's moderately annoying to execute, but it's not more than a dozen or two lines of code to work out the approximate trajectory.
Working out the exact optimum trajectory is rather harder, but it's not the hard bit of rocketry.
I believe I may have misremembered what I believe was a WHO paper on this.
http://ije.oxfordjournals.org/content/39/4/1064.full - for example - gives the figure as 20* more risky for anal than vaginal sex - 30* with the figures given seems entirely plausible for a study to have found, and for me to have remembered.
Your case raises the interesting issue of transmissibility.
It's been found through studies of cases like yours that 'vanilla' couples sex, where the partners are otherwise healthy apart from one being HIV+ have well under a percent (.3% IIRC) rate per act of transmitting HIV.
For anal, this rises to 30%.
The reproductive system - in the absence of sores or other problems due to other diseases - is remarkably good at protecting itself from disease.
"With EMP bomb, unlike a nuke, you don't waste energy to generate EMR in all the spectrum, with all the unneeded parts like visible light, IR and UV, and heat up surroundings to rather uncomfortable temperatures." - technically true, but somewhat misleading.
Around 0.1% of energy goes into EMP.
For a ten kiloton device, this is still the equivalent of 10 tons of explosive - in EMP.
But - a flux-compression-generator converts about a third of the energy into electricity, and then you get about half from the transmitter, if lucky.
So, to get the equivalent EMP to a 10 kiloton nuclear device, you need of the order of 60 tons of explosives alone.
The generator is likely to double that, and the transmission antenna and magnetrons (which have to be physically large so they don't just arc across) double it again.
So, of the order of 250 tons.
This is 'problematic' to get to a high altitude, where it needs to be, to have more than a local effect.
I note 10 25 ton truck bombs are going to be able to wreck large portions of most financial districts, and be considerably cheaper.
'terrorist' EMP weapons with more than a local (building or three) scale are fantasy.
Consider what tiny, tiny, tiny fraction of a percent they'd have to drop CPU load in every copy of windows, in order to equal the trivial saving they are attempting to make.
Assuming they are incompetent.
For example, the 'microsoft update' scheme is as I understand it run on an unencrypted protocol.
There would be nothing stopping office telling the update client to send a few bytes of data along with that stream.
This is not also - technically - an extremely complex and involved project.
It's conceptually rather simple.
A drawstring bag, a couple of solar panels - some ion thrusters, a fairly standard reaction control system.
None of these are inherently very expensive, compared to the purported 2 billion price tag.
In some ways, the potential for cost-saving between doing it the NASA way, and sanely is higher than it is for a comparatively complex device that has to undergo high stress, and work 100% of the time like a rocket.
For 99.99% of the mission - a random reset, and wait for commands from earth will do nothing to substantially delay or endanger the mission.
This is very different from the case of a rocket.
There is time to think, and to bring up second-string hardware to take over tasks.
Firstly, I'm extremely skeptical of one of the conclusions - 'flash will make a CRT monitor use more power' - which I just don't believe - it will use an amount of power dependent on the average screen brightness - which may be an increase over black.
LCDs are different - the panel does actually take some energy to change state, and the lag compensation circuitry will use more in motion.
Secondly - a huge part has been missed out of this.
Power consumption of the computer.
Flash, or javascript, even in the background, can considerably increase power.
For example, I just closed all of the flash/animated things in the background on other tabs in firefox, and the CPU usage is now bouncing around 2%, with the computer using 17W.
If I start up a new tab with some flash, and gif animations, it goes up to 25W. (+8W)
Even switching away from the tab only takes it to 23W or so. (+5W)
It would be interesting to work out the total electricity wasted by common flash ads.
To a degree. ... than to add the extra complexity required for error tolerant computing.
It's more complex than this.
Mainstream computers basically assume error-free operation - because it's cheaper to run the devices a little slower - or to use more area or
You can construct computers with gates that are 99% reliable quite easily.
90% requires a lot more check logic.
By the time you hit something like 66%, the design is many times the size of the 'error free' one.
BBSs would clearly not have won. ... or a conglomeration of several of these providers with interoperability between them.
The more likely winner would have been AOL, compuserv,
Once you get enough 'bums on seats' - there is a network effect - why would someone get on the internet when it had fewer sites?
There seems to be a general assumption by many that the internet was predestined to win out over these other pre-existing nets.
It wasn't.
Things like the much derided Al Gore 'invention of the internet' - he was instrumental in securing some funding for non-educational use.
If the existing services that were taking off when the internet came along from behind had gotten their acts together - and gotten for example inter-provider mail working, the internet in its present form may not have happened.
It could so easily have been that if you wanted to make a page to advertise your business, it wasn't a case of simply sign up to one of the many thousands of hosting providers - but three or four large companies dominate.
Mine too!
I strongly recommend watching the Kepler conference.
http://keplergo.arc.nasa.gov/ScienceKepSciCon1.shtml
This is awesome!
You need some science background - if you don't know what a harmonic is, or a power spectra - you'll be pretty lost.
But as it's a new field, I was able to keep up with about 80% of the content, even though I only have a couple of semesters of physics under my belt, and a very limited understanding of the maths.
Not quite.
Kepler was designed to detect earth-like planets.
It does this by detecting the dimming of the star when a planet passes in front of it.
Unfortunately, the sun has turned out to not be very typical.
Most stars are much more flickery than the sun - which we diddn't realise until Kepler.
This means that it's quite hard to pick up an earth-like planet in an earth-like orbit crossing the star.
Both larger planets - they obscure more of the star, so are more visible, and closer in - they orbit much more rapidly, so you can add up the crossings) are significantly easier to detect.
The extended mission would get Kepler about to its initial mission goals - in the face of stars turning out to be more twinkly than expected.
Detecting reliably earth-like planets around candidate stars.
It will coincidentally allow the detection of more very distant large planets, and close-in very small planets.
Well - yes, and no.
The fundamental problem with microwaves is - they're microwaves. ... - they undergo diffraction.
They are just another sort of radio, and like all radio waves, and light, and
This limits how much you can focus them.
A 'small' transmitter antenna of say 1km, with microwaves of about 10cm wavelength, will have a beamwidth of about:
1.22*.1m / 1000m.
This is a beam which spreads about one part in ten thousand.
After 10000km, the beam will be one kilometer in diameter. At the distance of the moon - 40km.
So, you need an antenna 4km in diameter on your craft simply to pick up one percent of the beam at the moon.
Range is a major problem.
Lasers work somewhat better - but have their own annoying issues.
Well over a decade.
The fundamental problem with ion thrusters (as a general class) is that you trade power use for fuel use.
Yes, they may use lots less fuel.
http://en.wikipedia.org/wiki/Specific_impulse#Examples - for example.
An advanced ion thruster may use nearly 1/50th of the fuel of a conventional rocket engine.
But, it needs 50 times the power to do this.
So, to replace a conventional rocket engine burning a kilo of fuel a second, and producing a thrust of perhaps 500kg, with no electrical requirements, you need about 20 grams of fuel a second, and around 450 megawatts of power.
Needless to say - for many applications, the power plant ends up heavier than the engine it's replacing.
It only works in very low thrust applications.
The low thrust also brings other problems.
For example, around the earth is a belt of charged particles.
Ascending through these on conventional rockets is not a problem. You do it so rapidly.
With ion engines, you need to slowly spiral out (due to being power limited), and your whole craft gets highly irradiated.
It's trivial to add arbitrary metals to disguise the origin.