The spreads that exist now are not an inherent feature of bitcoin, it's just an artifact of it being new. Assume a brokerage house takes the place of a bank, as far as maintaining accounts for their customers. The brokerage house holds an assortment of assets for their customers, but which assets are connected to any given customer gets changed by bitcoin payment messages and the rules that customer has set up for their account (ie I want my account to hold 10% gold, 30% houses, and 60% S&P 500 index funds).
A traditional bank only holds one asset for their customers, dollars. When a payment message comes in (traditionally a check, but these days a debit card transaction), the amount in their balance gets reduced, and someone else gets increased. In the example above, the same thing happens, except now the account has a pool of assets instead of just dollars. There will of course be costs for the brokerage to run such a system, but there are costs to running banks too. Checking accounts either have fees or don't pay interest on your balances.
The conversion from bitcoin transaction messages to asset pool can be automated and cheap in principle, as cheap as processing a debit card swipe is now. Such systems don't exist yet, but I see no reason they cannot evolve in time.
No. When you download a magnet link from the Pirate Bay, or equivalent, all you have is a hash value, and possibly some tracker names. Somewhere on the network the.torrent file (which has checksums for the blocks and other metadata) is hosted by some other user. The hash value leads you connect with that user, if you have no tracker data, and you get the.torrent file delivered. At that point you don't have any part of the content files yet.
Via one of the peering networks (DHT, Peer Exchange, etc) or a tracker (if this torrent has some) you can now announce your presence, make connections to others in the swarm, and start to ask for blocks. Once you have at least one block, you can start sending them to others. Sending to others is considered the illegal act, since you are making a copy.
The peers you are connected to usually report how much of the files they have. If they have less than 100%, they are called leechers, and if they have 100% they are called seeders, but the protocol works the same for both. You just stop asking for new blocks once you have all of them. When you have part of the full set, you can be sending and getting blocks at the same time. That accounts for how popular swarms can grow quickly. As soon as you have one block, you can start passing it on, and a new swarm only has to send one full set from the original seeder to some number of other people, in pieces. Once a full set is "in the swarm", the original seeder can leave, and then the other people can swap pieces until everyone has the full set. That many-to-many swapping is what lets one seed become 10000 for a popular movie.
(I'm sure others will correct me if any of the above is wrong)
The value of Bitcoin only matters as long as it takes to convert to something else. If that period is short, which it can be for electronic currency, the absolute value does not matter, just the exchange ratios.
You can separate the function of "transaction processing" from "store of value", and assign Bitcoin the first, and something more physical like gold or houses to the second. The beauty of doing this is I can pay in gold, and you can receive houses in payment, as long as there is an efficient conversion and transaction system in the middle. Instead of depending on someone elses choice of store of value, you can pick whichever you like best.
When I talk of gold and houses, of course for buying coffee we are talking fractional gold bars or houses. Those might be implemented as shares in funds which hold the physical assets.
I have a solution for that. Combine scoop mining of the Earth's atmosphere and mining the debris belt for raw materials/working parts/satellite refuel and repair station:
The first gives you a relatively cheap source of fuel for your electric thruster to putter around orbit, the second makes use of that fuel to do something useful. Depending on the state of the dead satellite or debris you can either:
- Lower it's orbit enough to re-enter quickly if you can't make any other use of it - Feed it into a processing unit as raw materials - Salvage it for working parts - Repair broken parts to return satellite to operation - Refuel satellites that are otherwise functional and just ran out of fuel.
It's basically the same service a tow truck and garage provides on Earth, except in space. If we never picked up road debris on Earth, it would be a mess too. What we were lacking is an efficient way to pick up space debris, and the combination of mining air from low orbit + electric thrusters is around a 100 times improvement in propulsion efficiency.
When near empty, the stages are 10-30 times lighter, because they don't have much fuel, or in the case of lower stages, don't have the upper stages sitting on them. Most of the velocity is lost to a heat shield, so the landing thrust only has to take off 10% or less of the remaining velocity. So it doesn't take that much fuel to land. It takes less fuel than the weight of wings to land.
No, but Air Launch does reduce several of the losses a regular rocket has at ground level, and approximately doubles the payload to orbit:
* Reduced gravity loss, when the rocket is flying vertical. Only horizontal velocity gets you in orbit. Horizontal launch avoids most of this * Reduced aerodynamic drag on the rocket because it starts above most of the atmosphere * Increased thrust, because at sea level rocket engines lose thrust due to fighting air pressure * Velocity of the airplane takes about 3% off what the rocket needs to do * Altitude of the airplane gives some potential energy
Those are in about the order of relative importance. The vertical part of a standard launch is incredibly inefficient. If you take off at a typical 1.5 gees, 2/3 is wasted simply fighting gravity.
Use the fuel for electric tugs to collect orbital debris, salvage dead satellites, or repair/refuel ones that can be fixed. Anything that cannot be recycled/reused gets brought down to air mining altitude, where it will quickly de-orbit. The problem until now was debris was in such scattered orbits you could not afford to go collect it. The combination of mining the upper atmosphere for fuel and electric thrusters is so much better, that now you can.
For those who don't understand how the scoop works, you are collecting air at 7.5 km/s inlet velocity, and your thruster works at 30-50 km/s exhaust velocity. So you only use part of your collected air mass to make up for drag and keep the rest. You do this at ~200 km altitude, which is still a vacuum by ordinary standards, but is just low enough that you can collect and pump it into a tank. You need healthy size solar arrays to power the thrusters.
The work they do is cryptographically securing the transaction history and account ledger for Bitcoins (who owns how many coins). If that is not useful, then you must also believe that the internal work that banks do tracking transactions and account balances is useless.
Nevada Cayembe in Ecuador is the best place to leave from. It's the highest point on the Equator, and thus the best place on the planet to launch from. The altitude and reduced air pressure helps your rocket efficiency. Of course, once the Stratolaunch vehicle gets going, they can start a rocket higher and moving faster than any point on Earth. Nevertheless, Cayembe is a great place to put an accelerator type system:
Some spray paint works equally well. For deniability, dip a rag in dirty water and just smear the lens. Then just wait to see who comes to fix it. For added fun, set up your own counter-camera nearby to monitor the first camera repair.
Why bother is because bitcoin are more divisible than shares of stock, and have less transaction costs than buying and selling dollars or GLD shares on the market. The trader who maintains the GLD account balances for the users only has to trade the *net* amount of shares required by all the users put together, rather than each of them making a trade for small amounts. I'm not going to pay for coffee directly with my GLD shares because just the brokerage commission is about twice the price of the coffee, even if I was selling a fractional share (which you normally can't). But transfer rights to 70 millishares of GLD to the coffee shop is fine if the overhead is negligible.
Yes it is, hand holds, foot restraints, and outside they have bars for hooking safety cable clips to. Human muscles would be useless without something to push or pull against.
Not one person, but two people could do it. The "standard racks" on board the Station can mass up to 500 kg each, and are swapped out regularly with new experiments. The large square hatch is sized to fit one of those racks, but you need two people for enough control of the movement so it does not smash things along the way.
The standard racks are derived from earthly 19 inch equipment racks, with two of them side by side, and aircraft "seat tracks" are on the front to attach things to. Seat tracks are what the seats in an airplane are mounted to. They did not see a need to invent new things from scratch for the job of mounting hardware.
Imagine if you will, that bitcoins are used as a "transaction system" to transfer ownership of GLD shares (that's a NYSE traded trust that simply holds a lot of gold in a vault in London, $64B worth). To the user, they are holding gold, and the bitcoins are transparent to them, as they are just being used as the message system to change balances in accounts. To the extent users stay balanced, the GLD trader doesn't actually have to trade his GLD shares, just keep track of who owns how much.
The value of bitcoins in and of themselves does not matter then, as they are not held very long. You only need a method to price bitcoins in terms of gold for the duration of the transaction. Thereafter the account balance will be in GLD shares or ounces of gold. So there you go, shiny things traded by intangible data messages (bitcoin transaction messages).
Every 10 minutes a new signed data block is created, that includes transactions from that interval. It also includes the signature from the last block, forming a block chain that goes back to the origin of the bitcoin system. There are currently about 180,000 blocks, and the block chain data is currently stored on every user's machine. It's around 1.7 GB right now. Creating new blocks is what "mining" does, and miners don't need the whole block history, just the current transactions.
1.7 GB is not a big deal to store right now, so everyone gets a full copy. In the future, more dedicated systems will store the whole chain or they will truncate the early part of the active chain to an archive and only store the recent set on user machines. In other words, when the chain gets too big, store the first million blocks in an archive, and only keep the last 100K.
The rules also seem totally nuts when you see how they play out. You can discuss things with US Citizens, but only if you're in the US. Unless you're abroad, but in a place the US controls. But not if you're in the US and there's a person here on a visa nearby.
To give an example relevant to the original story, I worked for many years on the International Space Station. Note the International part. Nonetheless, when we had visitors from our foreign partners, we had to cover up our whiteboards and computer monitors lest they see some forbidden data. This being a piece of hardware occupied by foreigners most of the time once it's in orbit. Pretty silly, right?
Only the simplistic single noodle stationary space elevator (devised in 1895 for gosh sake) needs Unobtainium for building materials. For a more practical design see this page in a space engineering textbook I have been writing (along with anyone else who contributes, but mostly me so far):
The short version is that both rockets and space elevators get exponentially more massive with increased velocity. Therefore if you split the velocity to get to Earth orbit between the two methods, they *both* are much less massive than either by themselves. Thus a Skyhook type elevator that provides 2.4 km/s has a mass ratio of 16 times the arriving vehicle mass using existing carbon fiber and reasonable design margins (2.8:1 on the bare cable strength).
The rocket coming from the ground performs the remaining 6.6 km/s ideal velocity, and has a 13% payload fraction assuming LOX/H2 propellant. The ideal velocity is 27% lower than an unaided Single-Stage-to-Orbit rocket needs to do, which accounts for the higher payload. The Skyhook has a landing platform at the tip which the rocket does a vertical landing on. When returning to Earth, the rocket merely drops off the landing platform, and now has to dissipate slightly less than half the kinetic energy as returning from full orbit, so the heat shield problem is that much easier.
Your comment makes the common mistake of Earthlings, that distance equates to cost. On Earth it does, because transport involves either rolling friction, air drag, or wave drag, depending on transportation method. In space none of these apply, so the cost of transportation is related to velocity change, and not distance.
Dead synchronous communications satellites are spread out in a 263,000 km ring around the Equator, but they are all moving at nearly the same velocity, the amount to match the Earth's rotation and make them synchronous, so gathering them up won't take much velocity change. Also, new electric thrusters are ten times as efficient as old chemical thrusters, and make a wider range of missions possible than before.
Some of the dead comsats are still functional, and just ran out of station-keeping propellant to keep them in a fixed location. The point of synchronous satellites is all the ground antennas don't have to move, cause the satellites stay in one place in the sky. Fixing those satellites just involves clamping on a new fuel tank and thruster pack, and you are good to go.
More advanced repairs would involve remote controlled robots, likely, to replace other items like worn out or broken solar arrays. Fixing internal failures, like the amplifiers for the downlink transmitters would need a hangar and humans given our current robot capability, so that level of repair will need to wait for lower cost humans in orbit. At the least, we can gather the space junk into controlled orbits so it doesn't breed more space junk by collisions.
What are they going to find on a rock in space that is not already available on THIS rock in space?
61 MJ/kg of potential energy for one thing (the depth of the Earth's gravity well). Raw materials to bootstrap space industry for another. Your average space rock is 40% oxygen. If you use VASIMR type plasma thrusters to fetch the space rock, and you use oxygen as fuel, you burn 2.3% of the total rock mass to haul it back. Thus the remaining 97.7% of the rock, including a lot of oxygen, is available to use or sell to other people *in orbit*, where any mass is worth $5000/kg at the moment.
Any mass you cannot convert to useful items like water, O2, or steel, still has value as radiation shielding, and stockpile for later processing. At first you will only be making a few products, but add more over time. The key point is as soon as you can extract a little O2 from the first space rock, you are self sufficient on fuel *Forever*.
If you want a cannon, use an actual cannon, and not an electromagnetic accelerator. Pipe is way cheaper than than a series of coils and a frickin huge power supply to feed them. These big electromagnetic launchers leave out the part about how they brown out an entire state when launching. One Space Shuttle engine had the equivalent of 4 Hoover Dams power output (8 GW), or 8 nuclear power plants. The StarTram Generation 1 system will need 53 GW for 30 seconds.
This gun was built in the 1960's and reached orbital altitude but not orbital speed:
Is when Toshiba makes the purchase, will it be credit or debit?
Note that one of IBM's first products in 1911 was a commercial scale. Since supermarket POS systems usually include a scale for weighing produce, this ends a century of IBM selling weighing devices.
And surface type collisions (like object falls into water) generate a particle effect according to a spreadsheet. Water is already set up as a standard collision type, but you can make custom ones.
Also boolean destructibles (damage subracts from the object shape):
Of course, just because the features are in the game engine does not mean they actually get used come game development time. There is a limit to how much time they can spend making one game, so that limits what goes into it.
Slashdot Mirror
The spreads that exist now are not an inherent feature of bitcoin, it's just an artifact of it being new. Assume a brokerage house takes the place of a bank, as far as maintaining accounts for their customers. The brokerage house holds an assortment of assets for their customers, but which assets are connected to any given customer gets changed by bitcoin payment messages and the rules that customer has set up for their account (ie I want my account to hold 10% gold, 30% houses, and 60% S&P 500 index funds).
A traditional bank only holds one asset for their customers, dollars. When a payment message comes in (traditionally a check, but these days a debit card transaction), the amount in their balance gets reduced, and someone else gets increased. In the example above, the same thing happens, except now the account has a pool of assets instead of just dollars. There will of course be costs for the brokerage to run such a system, but there are costs to running banks too. Checking accounts either have fees or don't pay interest on your balances.
The conversion from bitcoin transaction messages to asset pool can be automated and cheap in principle, as cheap as processing a debit card swipe is now. Such systems don't exist yet, but I see no reason they cannot evolve in time.
No. When you download a magnet link from the Pirate Bay, or equivalent, all you have is a hash value, and possibly some tracker names. Somewhere on the network the .torrent file (which has checksums for the blocks and other metadata) is hosted by some other user. The hash value leads you connect with that user, if you have no tracker data, and you get the .torrent file delivered. At that point you don't have any part of the content files yet.
Via one of the peering networks (DHT, Peer Exchange, etc) or a tracker (if this torrent has some) you can now announce your presence, make connections to others in the swarm, and start to ask for blocks. Once you have at least one block, you can start sending them to others. Sending to others is considered the illegal act, since you are making a copy.
The peers you are connected to usually report how much of the files they have. If they have less than 100%, they are called leechers, and if they have 100% they are called seeders, but the protocol works the same for both. You just stop asking for new blocks once you have all of them. When you have part of the full set, you can be sending and getting blocks at the same time. That accounts for how popular swarms can grow quickly. As soon as you have one block, you can start passing it on, and a new swarm only has to send one full set from the original seeder to some number of other people, in pieces. Once a full set is "in the swarm", the original seeder can leave, and then the other people can swap pieces until everyone has the full set. That many-to-many swapping is what lets one seed become 10000 for a popular movie.
(I'm sure others will correct me if any of the above is wrong)
The value of Bitcoin only matters as long as it takes to convert to something else. If that period is short, which it can be for electronic currency, the absolute value does not matter, just the exchange ratios.
You can separate the function of "transaction processing" from "store of value", and assign Bitcoin the first, and something more physical like gold or houses to the second. The beauty of doing this is I can pay in gold, and you can receive houses in payment, as long as there is an efficient conversion and transaction system in the middle. Instead of depending on someone elses choice of store of value, you can pick whichever you like best.
When I talk of gold and houses, of course for buying coffee we are talking fractional gold bars or houses. Those might be implemented as shares in funds which hold the physical assets.
I have a solution for that. Combine scoop mining of the Earth's atmosphere and mining the debris belt for raw materials/working parts/satellite refuel and repair station:
* http://en.wikibooks.org/wiki/Space_Transport_and_Engineering_Methods/Resource_Extraction#Scoop_Mining
* http://en.wikibooks.org/wiki/Space_Transport_and_Engineering_Methods/Orbital_Mining2
The first gives you a relatively cheap source of fuel for your electric thruster to putter around orbit, the second makes use of that fuel to do something useful. Depending on the state of the dead satellite or debris you can either:
- Lower it's orbit enough to re-enter quickly if you can't make any other use of it
- Feed it into a processing unit as raw materials
- Salvage it for working parts
- Repair broken parts to return satellite to operation
- Refuel satellites that are otherwise functional and just ran out of fuel.
It's basically the same service a tow truck and garage provides on Earth, except in space. If we never picked up road debris on Earth, it would be a mess too. What we were lacking is an efficient way to pick up space debris, and the combination of mining air from low orbit + electric thrusters is around a 100 times improvement in propulsion efficiency.
When near empty, the stages are 10-30 times lighter, because they don't have much fuel, or in the case of lower stages, don't have the upper stages sitting on them. Most of the velocity is lost to a heat shield, so the landing thrust only has to take off 10% or less of the remaining velocity. So it doesn't take that much fuel to land. It takes less fuel than the weight of wings to land.
No, but Air Launch does reduce several of the losses a regular rocket has at ground level, and approximately doubles the payload to orbit:
* Reduced gravity loss, when the rocket is flying vertical. Only horizontal velocity gets you in orbit. Horizontal launch avoids most of this
* Reduced aerodynamic drag on the rocket because it starts above most of the atmosphere
* Increased thrust, because at sea level rocket engines lose thrust due to fighting air pressure
* Velocity of the airplane takes about 3% off what the rocket needs to do
* Altitude of the airplane gives some potential energy
Those are in about the order of relative importance. The vertical part of a standard launch is incredibly inefficient. If you take off at a typical 1.5 gees, 2/3 is wasted simply fighting gravity.
I know this is a problem, and I imagine smart people are trying to figure something out.
We already have. Orbital scoop mining for fuel supply:
http://en.wikibooks.org/wiki/Space_Transport_and_Engineering_Methods/Resource_Extraction#Scoop_Mining
Use the fuel for electric tugs to collect orbital debris, salvage dead satellites, or repair/refuel ones that can be fixed. Anything that cannot be recycled/reused gets brought down to air mining altitude, where it will quickly de-orbit. The problem until now was debris was in such scattered orbits you could not afford to go collect it. The combination of mining the upper atmosphere for fuel and electric thrusters is so much better, that now you can.
For those who don't understand how the scoop works, you are collecting air at 7.5 km/s inlet velocity, and your thruster works at 30-50 km/s exhaust velocity. So you only use part of your collected air mass to make up for drag and keep the rest. You do this at ~200 km altitude, which is still a vacuum by ordinary standards, but is just low enough that you can collect and pump it into a tank. You need healthy size solar arrays to power the thrusters.
The work they do is cryptographically securing the transaction history and account ledger for Bitcoins (who owns how many coins). If that is not useful, then you must also believe that the internal work that banks do tracking transactions and account balances is useless.
Nevada Cayembe in Ecuador is the best place to leave from. It's the highest point on the Equator, and thus the best place on the planet to launch from. The altitude and reduced air pressure helps your rocket efficiency. Of course, once the Stratolaunch vehicle gets going, they can start a rocket higher and moving faster than any point on Earth. Nevertheless, Cayembe is a great place to put an accelerator type system:
http://en.wikibooks.org/wiki/Space_Transport_and_Engineering_Methods/Human_Transport#Low_Acceleration_Guns
http://lh6.googleusercontent.com/-_izqCR4nsS0/T6bJLGsngcI/AAAAAAAAC1c/zA2p3C2doqA/s1577/Cayambe%2520Topo%2520Map.jpg
Some spray paint works equally well. For deniability, dip a rag in dirty water and just smear the lens. Then just wait to see who comes to fix it. For added fun, set up your own counter-camera nearby to monitor the first camera repair.
Why bother is because bitcoin are more divisible than shares of stock, and have less transaction costs than buying and selling dollars or GLD shares on the market. The trader who maintains the GLD account balances for the users only has to trade the *net* amount of shares required by all the users put together, rather than each of them making a trade for small amounts. I'm not going to pay for coffee directly with my GLD shares because just the brokerage commission is about twice the price of the coffee, even if I was selling a fractional share (which you normally can't). But transfer rights to 70 millishares of GLD to the coffee shop is fine if the overhead is negligible.
Yes it is, hand holds, foot restraints, and outside they have bars for hooking safety cable clips to. Human muscles would be useless without something to push or pull against.
Not one person, but two people could do it. The "standard racks" on board the Station can mass up to 500 kg each, and are swapped out regularly with new experiments. The large square hatch is sized to fit one of those racks, but you need two people for enough control of the movement so it does not smash things along the way.
The standard racks are derived from earthly 19 inch equipment racks, with two of them side by side, and aircraft "seat tracks" are on the front to attach things to. Seat tracks are what the seats in an airplane are mounted to. They did not see a need to invent new things from scratch for the job of mounting hardware.
Imagine if you will, that bitcoins are used as a "transaction system" to transfer ownership of GLD shares (that's a NYSE traded trust that simply holds a lot of gold in a vault in London, $64B worth). To the user, they are holding gold, and the bitcoins are transparent to them, as they are just being used as the message system to change balances in accounts. To the extent users stay balanced, the GLD trader doesn't actually have to trade his GLD shares, just keep track of who owns how much.
The value of bitcoins in and of themselves does not matter then, as they are not held very long. You only need a method to price bitcoins in terms of gold for the duration of the transaction. Thereafter the account balance will be in GLD shares or ounces of gold. So there you go, shiny things traded by intangible data messages (bitcoin transaction messages).
Every 10 minutes a new signed data block is created, that includes transactions from that interval. It also includes the signature from the last block, forming a block chain that goes back to the origin of the bitcoin system. There are currently about 180,000 blocks, and the block chain data is currently stored on every user's machine. It's around 1.7 GB right now. Creating new blocks is what "mining" does, and miners don't need the whole block history, just the current transactions.
1.7 GB is not a big deal to store right now, so everyone gets a full copy. In the future, more dedicated systems will store the whole chain or they will truncate the early part of the active chain to an archive and only store the recent set on user machines. In other words, when the chain gets too big, store the first million blocks in an archive, and only keep the last 100K.
Not completely removed, they are just suspending enforcement, but still contacting a few very heavy users.
The rules also seem totally nuts when you see how they play out. You can discuss things with US Citizens, but only if you're in the US. Unless you're abroad, but in a place the US controls. But not if you're in the US and there's a person here on a visa nearby.
To give an example relevant to the original story, I worked for many years on the International Space Station. Note the International part. Nonetheless, when we had visitors from our foreign partners, we had to cover up our whiteboards and computer monitors lest they see some forbidden data. This being a piece of hardware occupied by foreigners most of the time once it's in orbit. Pretty silly, right?
The protozoan was heard shouting "Hey you young species, get off my pond!"
Only the simplistic single noodle stationary space elevator (devised in 1895 for gosh sake) needs Unobtainium for building materials. For a more practical design see this page in a space engineering textbook I have been writing (along with anyone else who contributes, but mostly me so far):
http://en.wikibooks.org/wiki/Space_Transport_and_Engineering_Methods/Space_Elevator
The short version is that both rockets and space elevators get exponentially more massive with increased velocity. Therefore if you split the velocity to get to Earth orbit between the two methods, they *both* are much less massive than either by themselves. Thus a Skyhook type elevator that provides 2.4 km/s has a mass ratio of 16 times the arriving vehicle mass using existing carbon fiber and reasonable design margins (2.8:1 on the bare cable strength).
The rocket coming from the ground performs the remaining 6.6 km/s ideal velocity, and has a 13% payload fraction assuming LOX/H2 propellant. The ideal velocity is 27% lower than an unaided Single-Stage-to-Orbit rocket needs to do, which accounts for the higher payload. The Skyhook has a landing platform at the tip which the rocket does a vertical landing on. When returning to Earth, the rocket merely drops off the landing platform, and now has to dissipate slightly less than half the kinetic energy as returning from full orbit, so the heat shield problem is that much easier.
Your comment makes the common mistake of Earthlings, that distance equates to cost. On Earth it does, because transport involves either rolling friction, air drag, or wave drag, depending on transportation method. In space none of these apply, so the cost of transportation is related to velocity change, and not distance.
Dead synchronous communications satellites are spread out in a 263,000 km ring around the Equator, but they are all moving at nearly the same velocity, the amount to match the Earth's rotation and make them synchronous, so gathering them up won't take much velocity change. Also, new electric thrusters are ten times as efficient as old chemical thrusters, and make a wider range of missions possible than before.
Some of the dead comsats are still functional, and just ran out of station-keeping propellant to keep them in a fixed location. The point of synchronous satellites is all the ground antennas don't have to move, cause the satellites stay in one place in the sky. Fixing those satellites just involves clamping on a new fuel tank and thruster pack, and you are good to go.
More advanced repairs would involve remote controlled robots, likely, to replace other items like worn out or broken solar arrays. Fixing internal failures, like the amplifiers for the downlink transmitters would need a hangar and humans given our current robot capability, so that level of repair will need to wait for lower cost humans in orbit. At the least, we can gather the space junk into controlled orbits so it doesn't breed more space junk by collisions.
What are they going to find on a rock in space that is not already available on THIS rock in space?
61 MJ/kg of potential energy for one thing (the depth of the Earth's gravity well). Raw materials to bootstrap space industry for another. Your average space rock is 40% oxygen. If you use VASIMR type plasma thrusters to fetch the space rock, and you use oxygen as fuel, you burn 2.3% of the total rock mass to haul it back. Thus the remaining 97.7% of the rock, including a lot of oxygen, is available to use or sell to other people *in orbit*, where any mass is worth $5000/kg at the moment.
Any mass you cannot convert to useful items like water, O2, or steel, still has value as radiation shielding, and stockpile for later processing. At first you will only be making a few products, but add more over time. The key point is as soon as you can extract a little O2 from the first space rock, you are self sufficient on fuel *Forever*.
If you want technical details, you can look at the 80% complete wikibook I have been working on: http://en.wikibooks.org/wiki/Space_Transport_and_Engineering_Methods
If you want a cannon, use an actual cannon, and not an electromagnetic accelerator. Pipe is way cheaper than than a series of coils and a frickin huge power supply to feed them. These big electromagnetic launchers leave out the part about how they brown out an entire state when launching. One Space Shuttle engine had the equivalent of 4 Hoover Dams power output (8 GW), or 8 nuclear power plants. The StarTram Generation 1 system will need 53 GW for 30 seconds.
This gun was built in the 1960's and reached orbital altitude but not orbital speed:
http://en.wikipedia.org/wiki/Project_HARP
This one reached 3/8 of orbital speed in the early 1990's
http://www.astronautix.com/lvs/sharp.htm
Slightly faster one (1/2 orbital speed) would be a very effective launcher, replacing the whole first stage of a two stage rocket.
Is when Toshiba makes the purchase, will it be credit or debit?
Note that one of IBM's first products in 1911 was a commercial scale. Since supermarket POS systems usually include a scale for weighing produce, this ends a century of IBM selling weighing devices.
CryEngine 3 does do water interaction:
"User interaction with surface will generate waves propagation" from http://freesdk.crydev.net/display/SDKDOC2/Water+Shader
And surface type collisions (like object falls into water) generate a particle effect according to a spreadsheet. Water is already set up as a standard collision type, but you can make custom ones.
Also boolean destructibles (damage subracts from the object shape):
http://freesdk.crydev.net/display/SDKDOC3/Boolean+Destructibles
Of course, just because the features are in the game engine does not mean they actually get used come game development time. There is a limit to how much time they can spend making one game, so that limits what goes into it.
Have you been reading the book I've been working on?
https://en.wikibooks.org/wiki/Space_Transport_and_Engineering_Methods
If not, you may want to, and even contribute. It's a wiki project, so help is welcome, as long as you know what you are talking about.