Except the Bitcoin Network already runs at 324 Petahash/second, and each hash computation requires many floating point operations - 128 rounds of applying a complex hash function on several hundred bytes of data. Aurora competing for bitcoins won't make a significant difference in the network hash rate, it is too puny. The network already runs at ~1 million petaflops by dint of custom designed mining chips that perform the necessary calculations in hardware, massively parallel in each chip. Then you aggregate server rooms full of these chips into a mining farm.
You will need thrusters to position the big satellite in the first place (or the parts if it is assembled on site), and to counteract the Moon and Sun's tidal forces. If you can handle those, light pressure will be a small issue.
> I think a large problem is going to be space debris -
Nope. If you can build giant solar arrays in GEO, you can build small ones and attach ion thrusters to them. See the Dawn mission at Ceres and the Asteroid Redirect Mission NASA is proposing for examples. These space tugs can putter around and collect loose space debris. That however does not eliminate natural meteoroids. So your power satellite will need a maintenance program, or just accept a small amount of degradation as stuff hits it.
Solar arrays are thin, so most debris will just punch a small hole.
> The biggest unknown is the microwave link to send power to Earth.
We actually have tons of data about this, from all the GEO communications satellites, and rain fade that happens sometimes.
> The next-biggest unknown is availability of construction materials.
I was one of the people who worked on this issue while at Boeing. We found that 98% of the materials for a solar power satellite can be obtained from the Moon. A higher percentage are available if you use the Moon + Near Earth Asteroids. We didn't do the numbers for the NEO case back in the 1980's, since we had only discovered ~150 back then vs 12,500 today, and ion thrusters were not fully developed until about the year 2000. A modern study would account for both sources of materials.
We solved that problem early in the Solar Power Satellite studies at Boeing. The microwave transmitter in orbit is a phased array. The reference signal to adjust the phase is a transmitter in the center of the rectenna on the ground, powered by the rectenna. If the beam wanders off target, no reference signal, and the beam is no longer focused.
* Spectrolab rates their space solar panels for 20 years at GEO: http://www.spectrolab.com/Data.... Since they don't need to withstand weather, they can be much lighter than ground-mounted panels. 13 W/kg for a typical ground panel (not counting mounting and tracker) vs 177 W/kg for the space ones. That has implications for the energy payback time if you manufacture the panels in space.
* Your comparison of operating hours neglects that in space you have 36% higher insolation, because there is no atmospheric absorption. Therefore it takes fewer cells to produce the same output. Also the Nevada desert is an excellent location on Earth. The average location on Earth gets considerably worse hours of sunlight. Since we can't transmit power all over the Earth, cherry-picking a good location is unfair.
SpaceX couldn't get an export license then. Rockets fall under the "International Traffic in Arms Regulations" (ITAR) and need a license to export. We even had to follow those rules for the Space Station modules being built by Boeing. That's despite it being an international station occupied by lots of foreigners, Russians even.
> It does seem that the ULA has been mostly sitting on their laurels sucking at the government teat for a long while now.
Let me explain how this works. At the start of the Sea Launch program, which Boeing was a partner of, and I was working on, our program manager was an ex-Air Force officer who was a launch director from Vandenberg (where the Air Force launches polar satellites). He was a smart and competent guy, but the main reason Boeing hired him is *he knew all the right players on the Air Force side*. Another manager of mine was a former Marines officer who had done helicopter procurement.
When the people who make the buying decisions already know you, because they used to work with you, you have a much better chance than someone they never met before and have no idea how good they are, if they will get along, etc. This "revolving door" works in the other direction too, where someone in industry then goes to work in government, in the same field. The problem is you often can't find anyone else who is qualified to oversee such contracts.
> And no effective way to store it for use at night and the evenings.
I guess you haven't heard of solar thermal with storage. You concentrate sunlight with curved troughs or steerable mirrors. This is used to heat a storage material such as thermal oil or rocks. In the off-hours you use the heat to boil water, and the steam runs through a tubine-generator set like in conventional fossil plants. There haven't been a lot of thermal storage units built yet *because we don't need them yet*. For example, the 400 MW Ivanpah solar thermal plant is on the same power line as Hoover Dam. The dam serves as storage by not using water when Ivanpah is running, and saving it for night-time. Eventually you run out of existing storage capacity, and need to add more, but we are not there yet in most places.
* Curiosity has almost twice the landed weight of the Viking Landers * Rocket thrusters firing at ground level would contaminate the soil, which they wanted to analyze * Curiosity is a rover. You either are carrying dead weight from the propulsion system, or need a roll-off ramp * Curiosity's wheels and suspension allowed landing on rougher ground by landing on them directly. Rocket thrusters might have damaged the wheels by throwing rocks around
Elon Musk wants to build a Mars Colony too, but he has a rocket factory (SpaceX), and several other businesses that can earn lots of money *and* supply hardware for Mars: Tesla (electric cars on Earth, electric rovers on Mars), Solar City (home roofs, and soon high efficiency cells for Earth and Mars), and the Gigafactory (batteries for vehicles *and* nighttime backup for solar panels). So his plan is a lot more feasbile than Mars One's.
The real question is where is Mars One going to get the $6 billion they estimate for their project? If they have that money, they can hire the right aerospace companies and engineers to build real hardware. But without it, they just have pretty pictures on a website, and aren't going anywhere.
And as someone who helped build the Space Station, and written a book on Space Systems Engineering ( http://en.wikibooks.org/wiki/S... ), Mars One isn't being innovative *enough* to really bring down costs.
Sounds like someone failed to do a proper "systems engineering" job in the first place. Part of that job is identifying system interfaces between the parts early, then controlling the interface. In computer terms, the PCI specification is the interface between the PCI slot and the PCI card that goes in the slot. You have to control that specification so the parts will work together. A rocket and the launch site it uses are just bigger and more complicated interfaces.
Then the answer is not to send the hardware to empty buildings, but to install a GPS tracking device in the shipping container, and see where it goes off-course. Bonus points if you can track it all the way to the NSA modification warehouse, but at least if you know where it got diverted, you can figure out *how* it gets diverted. I suspect the truck drivers are in on it, but without tracking data, that is just a theory.
The head of the Mars Society is Robert Zubrin, who is a well qualified and inventive aerospace engineer. I assume the rest of their work at least involves doing the relevant math.
The Mars One project's problem isn't wanting to go to Mars, it's the missing step two in their plan:
(1) Raise around a million dollars from crowdsourcing, tee shirt sales, and application fees (2) ??? (3) Finish $6 billion worth of space hardware and launch it.
Elon Musk/SpaceX also want to go to Mars, but they have actual rockets and customers, and his other businesses (Tesla and Solar City) both stand to make a lot of money, and are useful to the original goal. You will need electric rovers, batteries for power storage, and solar panels on Mars. It helps if you have companies that already make that stuff. So I rate the SpaceX Mars program way higher on the probability scale.
Hey, uninformed person, these drones have lithium batteries, and sunlight is more powerful at high altitude due to less atmospheric absorption. So it can fly for years or until something breaks.
> Could you not place solar panels underneath the windmills?
In theory yes. In practice the wind resource is highest in the Midwest, and certain mountain passes. Midwest combines wind and field crops, because the wind turbine only needs about 1% of the land area to install the tower and the access road. The turbine as a whole doesn't create too much shade, so crops grow just fine around it. Mountain passes have too much geography in the way, and are not ideal for collecting sunlight.
Solar is getting installed preferentially in dry areas of the Southwest, because you get more sunlight hours per year there, and on industrial/commercial and home rooftops, because it's easier to compete with retail electric rates. The big desert solar farms have to compete with wholesale utility plants. It's popping up in other places too, I saw some panels in a field in NW Georgia, but the ones I mention above account for most of the installations at present.
There is no need to terraform the bulk of Mars until you have enough people there to justify it. Until then it makes much more sense to restrict the terraforming to the space underneath your habitat domes and arches.
Ideas that Mr. Robinson may not have been aware of also make colonizing easier. One is "Seed Factories" - self upgrading automation that grows from a starter kit, the way a tree grows from an acorn. The starter kit includes plans for the sequential addition of new machines, until you have a fully grown industrial capacity. Another is an improved space elevator system. The static ground-to-synchronous orbit elevator is not the lowest mass design by a long shot, and improved designs can be built with today's materials, rather than requiring "unobtainium".
> Of course I could be nitpicking and point out that the sun actually is a huge nuclear reactor.
We live near an unshielded gravitational confinement fusion reactor, that floods the entire Solar System with several kinds of lethal radiation. We only survive here on Earth because we have a strong magnetic field *and* a thick atmosphere to protect us. Even so, the Sun causes over 100,000 cases of malignant skin cancer every year, and lots of other causes of death. It would never have passed safety review if we treated it like we do new power sources.
There's another reason besides the ones you mention. Parts of the Moon have Thorium concentrations of 15 parts/million. That's about 1000 times higher than the He-3 concentration, and the energy output from fission isn't that much lower than fusion. Not to mention we know how to build Thorium reactors. So for a given amount of mining work, you would get more energy mining Thorium on the Moon. Now, considering that Thorium isn't terribly scarce on Earth, you can figure out that Lunar mining for Earth use isn't very sensible. And if you need power on the Moon, solar works much more easily. Nighttime power can be handled with solar-thermal. Vacuum makes a great insulator. Heat up a bunch of rocks with concentrated sunlight, then use that heat to run a generator at night. You will never run out of rocks on the Moon's surface, nor sunlight for that matter.
> Wind turbine speed doesn't change nearly as fast as you think it does.
Agreed. A single wind turbine has flywheel inertia in the blades, so it doesn't instantly stop and start. A whole wind farm changes even more slowly, because the turbines are typically spaced about 400 meters apart, and average wind speed is ~6 m/s, thus about a minute between turbines. Across many turbines in a wind farm, you are talking about ~10 minutes. Across a grid with multiple wind farms, the reaction time is even longer for a change in wind speed to propagate.
> People always say this about "Hollywood accounting" but I seriously doubt that the tax authorities (for instance) just let film companies make up their profit figure.
Hollywood was invaded by organized crime a long time ago through the stagehands labor unions. Read the credits on a film sometime. Do you really need 20 catering staff on call? The method is to pad staffing, with people who aren't really needed, or in some cases don't even exist. The movie production company writes off the expenses, with payrolls and invoices to make the IRS happy. They show a loss on the movie. But the padded expenses come back under the table.
It makes the IRS' job harder that many films are made by production companies organized by the job, hiring staff and laying them all off when the movie is done.
> There is no multi-billion dollar return for putting people on Mars.
Actually, there almost was, in the 1980's. A major TV network came to Boeing, where I worked at the time, and asked us how much for a Mars mission. We worked out a mission concept, and gave them an estimate. The network figured they could sell as much advertising for the mission as an Olympic games, but spread over a couple of years. Unfortunately the mission cost we came up with was twice the ad revenue, so it died at that point.
If you can boost the revenue with things like "Mars, the video game", and "Mars, the branded merchandise", and cut costs with modern technology, you *might* get it within reach of break-even. Throw in some government-funded science payloads, and it might work a profit.
Back then, there were only three TV networks, and they could command a big audience. I'm not sure a network could front that much these days, although they still compete for the Olympics.
Slashdot Mirror
Except the Bitcoin Network already runs at 324 Petahash/second, and each hash computation requires many floating point operations - 128 rounds of applying a complex hash function on several hundred bytes of data. Aurora competing for bitcoins won't make a significant difference in the network hash rate, it is too puny. The network already runs at ~1 million petaflops by dint of custom designed mining chips that perform the necessary calculations in hardware, massively parallel in each chip. Then you aggregate server rooms full of these chips into a mining farm.
You will need thrusters to position the big satellite in the first place (or the parts if it is assembled on site), and to counteract the Moon and Sun's tidal forces. If you can handle those, light pressure will be a small issue.
> I think a large problem is going to be space debris -
Nope. If you can build giant solar arrays in GEO, you can build small ones and attach ion thrusters to them. See the Dawn mission at Ceres and the Asteroid Redirect Mission NASA is proposing for examples. These space tugs can putter around and collect loose space debris. That however does not eliminate natural meteoroids. So your power satellite will need a maintenance program, or just accept a small amount of degradation as stuff hits it.
Solar arrays are thin, so most debris will just punch a small hole.
> The biggest unknown is the microwave link to send power to Earth.
We actually have tons of data about this, from all the GEO communications satellites, and rain fade that happens sometimes.
> The next-biggest unknown is availability of construction materials.
I was one of the people who worked on this issue while at Boeing. We found that 98% of the materials for a solar power satellite can be obtained from the Moon. A higher percentage are available if you use the Moon + Near Earth Asteroids. We didn't do the numbers for the NEO case back in the 1980's, since we had only discovered ~150 back then vs 12,500 today, and ion thrusters were not fully developed until about the year 2000. A modern study would account for both sources of materials.
We solved that problem early in the Solar Power Satellite studies at Boeing. The microwave transmitter in orbit is a phased array. The reference signal to adjust the phase is a transmitter in the center of the rectenna on the ground, powered by the rectenna. If the beam wanders off target, no reference signal, and the beam is no longer focused.
Hi Maury,
* Spectrolab rates their space solar panels for 20 years at GEO: http://www.spectrolab.com/Data.... Since they don't need to withstand weather, they can be much lighter than ground-mounted panels. 13 W/kg for a typical ground panel (not counting mounting and tracker) vs 177 W/kg for the space ones. That has implications for the energy payback time if you manufacture the panels in space.
* Your comparison of operating hours neglects that in space you have 36% higher insolation, because there is no atmospheric absorption. Therefore it takes fewer cells to produce the same output. Also the Nevada desert is an excellent location on Earth. The average location on Earth gets considerably worse hours of sunlight. Since we can't transmit power all over the Earth, cherry-picking a good location is unfair.
SpaceX couldn't get an export license then. Rockets fall under the "International Traffic in Arms Regulations" (ITAR) and need a license to export. We even had to follow those rules for the Space Station modules being built by Boeing. That's despite it being an international station occupied by lots of foreigners, Russians even.
> It does seem that the ULA has been mostly sitting on their laurels sucking at the government teat for a long while now.
Let me explain how this works. At the start of the Sea Launch program, which Boeing was a partner of, and I was working on, our program manager was an ex-Air Force officer who was a launch director from Vandenberg (where the Air Force launches polar satellites). He was a smart and competent guy, but the main reason Boeing hired him is *he knew all the right players on the Air Force side*. Another manager of mine was a former Marines officer who had done helicopter procurement.
When the people who make the buying decisions already know you, because they used to work with you, you have a much better chance than someone they never met before and have no idea how good they are, if they will get along, etc. This "revolving door" works in the other direction too, where someone in industry then goes to work in government, in the same field. The problem is you often can't find anyone else who is qualified to oversee such contracts.
> And no effective way to store it for use at night and the evenings.
I guess you haven't heard of solar thermal with storage. You concentrate sunlight with curved troughs or steerable mirrors. This is used to heat a storage material such as thermal oil or rocks. In the off-hours you use the heat to boil water, and the steam runs through a tubine-generator set like in conventional fossil plants. There haven't been a lot of thermal storage units built yet *because we don't need them yet*. For example, the 400 MW Ivanpah solar thermal plant is on the same power line as Hoover Dam. The dam serves as storage by not using water when Ivanpah is running, and saving it for night-time. Eventually you run out of existing storage capacity, and need to add more, but we are not there yet in most places.
Several reasons:
* Curiosity has almost twice the landed weight of the Viking Landers
* Rocket thrusters firing at ground level would contaminate the soil, which they wanted to analyze
* Curiosity is a rover. You either are carrying dead weight from the propulsion system, or need a roll-off ramp
* Curiosity's wheels and suspension allowed landing on rougher ground by landing on them directly. Rocket thrusters might have damaged the wheels by throwing rocks around
Elon Musk wants to build a Mars Colony too, but he has a rocket factory (SpaceX), and several other businesses that can earn lots of money *and* supply hardware for Mars: Tesla (electric cars on Earth, electric rovers on Mars), Solar City (home roofs, and soon high efficiency cells for Earth and Mars), and the Gigafactory (batteries for vehicles *and* nighttime backup for solar panels). So his plan is a lot more feasbile than Mars One's.
The real question is where is Mars One going to get the $6 billion they estimate for their project? If they have that money, they can hire the right aerospace companies and engineers to build real hardware. But without it, they just have pretty pictures on a website, and aren't going anywhere.
And as someone who helped build the Space Station, and written a book on Space Systems Engineering ( http://en.wikibooks.org/wiki/S... ), Mars One isn't being innovative *enough* to really bring down costs.
Our supposedly omnipotent spy agency should be able to track down where these posts are coming from. Their silence on this matter is deafening.
Sounds like someone failed to do a proper "systems engineering" job in the first place. Part of that job is identifying system interfaces between the parts early, then controlling the interface. In computer terms, the PCI specification is the interface between the PCI slot and the PCI card that goes in the slot. You have to control that specification so the parts will work together. A rocket and the launch site it uses are just bigger and more complicated interfaces.
Then the answer is not to send the hardware to empty buildings, but to install a GPS tracking device in the shipping container, and see where it goes off-course. Bonus points if you can track it all the way to the NSA modification warehouse, but at least if you know where it got diverted, you can figure out *how* it gets diverted. I suspect the truck drivers are in on it, but without tracking data, that is just a theory.
The head of the Mars Society is Robert Zubrin, who is a well qualified and inventive aerospace engineer. I assume the rest of their work at least involves doing the relevant math.
The Mars One project's problem isn't wanting to go to Mars, it's the missing step two in their plan:
(1) Raise around a million dollars from crowdsourcing, tee shirt sales, and application fees
(2) ???
(3) Finish $6 billion worth of space hardware and launch it.
Elon Musk/SpaceX also want to go to Mars, but they have actual rockets and customers, and his other businesses (Tesla and Solar City) both stand to make a lot of money, and are useful to the original goal. You will need electric rovers, batteries for power storage, and solar panels on Mars. It helps if you have companies that already make that stuff. So I rate the SpaceX Mars program way higher on the probability scale.
Hey, uninformed person, these drones have lithium batteries, and sunlight is more powerful at high altitude due to less atmospheric absorption. So it can fly for years or until something breaks.
> Could you not place solar panels underneath the windmills?
In theory yes. In practice the wind resource is highest in the Midwest, and certain mountain passes. Midwest combines wind and field crops, because the wind turbine only needs about 1% of the land area to install the tower and the access road. The turbine as a whole doesn't create too much shade, so crops grow just fine around it. Mountain passes have too much geography in the way, and are not ideal for collecting sunlight.
Solar is getting installed preferentially in dry areas of the Southwest, because you get more sunlight hours per year there, and on industrial/commercial and home rooftops, because it's easier to compete with retail electric rates. The big desert solar farms have to compete with wholesale utility plants. It's popping up in other places too, I saw some panels in a field in NW Georgia, but the ones I mention above account for most of the installations at present.
There is no need to terraform the bulk of Mars until you have enough people there to justify it. Until then it makes much more sense to restrict the terraforming to the space underneath your habitat domes and arches.
Ideas that Mr. Robinson may not have been aware of also make colonizing easier. One is "Seed Factories" - self upgrading automation that grows from a starter kit, the way a tree grows from an acorn. The starter kit includes plans for the sequential addition of new machines, until you have a fully grown industrial capacity. Another is an improved space elevator system. The static ground-to-synchronous orbit elevator is not the lowest mass design by a long shot, and improved designs can be built with today's materials, rather than requiring "unobtainium".
> Of course I could be nitpicking and point out that the sun actually is a huge nuclear reactor.
We live near an unshielded gravitational confinement fusion reactor, that floods the entire Solar System with several kinds of lethal radiation. We only survive here on Earth because we have a strong magnetic field *and* a thick atmosphere to protect us. Even so, the Sun causes over 100,000 cases of malignant skin cancer every year, and lots of other causes of death. It would never have passed safety review if we treated it like we do new power sources.
Parts of the Moon have natural concentrations of Thorium in the 10 ppm range. A little nuclear waste won't make a difference:
https://upload.wikimedia.org/w...
> And lunar He-3 mining is pretty useless.
There's another reason besides the ones you mention. Parts of the Moon have Thorium concentrations of 15 parts/million. That's about 1000 times higher than the He-3 concentration, and the energy output from fission isn't that much lower than fusion. Not to mention we know how to build Thorium reactors. So for a given amount of mining work, you would get more energy mining Thorium on the Moon. Now, considering that Thorium isn't terribly scarce on Earth, you can figure out that Lunar mining for Earth use isn't very sensible. And if you need power on the Moon, solar works much more easily. Nighttime power can be handled with solar-thermal. Vacuum makes a great insulator. Heat up a bunch of rocks with concentrated sunlight, then use that heat to run a generator at night. You will never run out of rocks on the Moon's surface, nor sunlight for that matter.
> There's not much to do in space.
Yeah, that's why space industry is only $300 billion/year and growing.
> Wind turbine speed doesn't change nearly as fast as you think it does.
Agreed. A single wind turbine has flywheel inertia in the blades, so it doesn't instantly stop and start. A whole wind farm changes even more slowly, because the turbines are typically spaced about 400 meters apart, and average wind speed is ~6 m/s, thus about a minute between turbines. Across many turbines in a wind farm, you are talking about ~10 minutes. Across a grid with multiple wind farms, the reaction time is even longer for a change in wind speed to propagate.
> People always say this about "Hollywood accounting" but I seriously doubt that the tax authorities (for instance) just let film companies make up their profit figure.
Hollywood was invaded by organized crime a long time ago through the stagehands labor unions. Read the credits on a film sometime. Do you really need 20 catering staff on call? The method is to pad staffing, with people who aren't really needed, or in some cases don't even exist. The movie production company writes off the expenses, with payrolls and invoices to make the IRS happy. They show a loss on the movie. But the padded expenses come back under the table.
It makes the IRS' job harder that many films are made by production companies organized by the job, hiring staff and laying them all off when the movie is done.
> There is no multi-billion dollar return for putting people on Mars.
Actually, there almost was, in the 1980's. A major TV network came to Boeing, where I worked at the time, and asked us how much for a Mars mission. We worked out a mission concept, and gave them an estimate. The network figured they could sell as much advertising for the mission as an Olympic games, but spread over a couple of years. Unfortunately the mission cost we came up with was twice the ad revenue, so it died at that point.
If you can boost the revenue with things like "Mars, the video game", and "Mars, the branded merchandise", and cut costs with modern technology, you *might* get it within reach of break-even. Throw in some government-funded science payloads, and it might work a profit.
Back then, there were only three TV networks, and they could command a big audience. I'm not sure a network could front that much these days, although they still compete for the Olympics.