Timothy Lord for Slashdot: So today you talked a little bit about efficiency and the idea of power efficiency when it comes to space missions. Can you explain that a little bit? And talk about you used the phrase of cost of the first kilowatt hour.
John: So there are a couple of big issues in all energy systems. The one is the cost what you must invest in order to put a new source of energy into place; and the second is sort of the recurring cost of the energy that comes from that new source of power. So whether it is a hydroelectric dam on earth or a nuclear power plant or a coal-fired power plant, these two considerations: the cost to have the power and then the cost of the electricity that comes from that new power source. And in space, in fact, the cost to deploy power and the cost of electricity that come from those power sources is wildly more expensive than the cost of energy here on earth. For example, a home here in the Austin Texas area might use 3 or 4 or 5 kilowatts of power, and for every kilowatt hour of energy that comes from that electrical power the cost might be 10 cents per kilowatt hour. Now in a place like Hawaii where energy must be shipped in, the cost of the power plant might be the same, but the cost of the electricity might be 25 cents a kilowatt hour, not 10 cents a kilowatt hour.
Slashdot: They have to bring in fuel?
John: Because they have to bring in the fuel. Typically in Hawaii it is a case of diesel oil. Now in more remote locations with a smaller industrial base, like say an island in the Bahamas or some place in Southeast Asia, it could be 40 cents a kilowatt hour. But in space not only is the cost of the system that is going to deliver the power much higher, the cost of electricity is much, much, much higher. So instead of that 10 cents per kilowatt hour that you might see on earth, the cost of electricity say for example on the International Space Station might be anywhere from $25 per kilowatt hour to $50 a kilowatt hour or more, i.e., 500 times to a 1000 times more than it would be here on earth. And if you look at ambitious things that we might want to do out on the Moon or in other places around the Solar System, sending people to Mars—none of that is going to happen without energy. And very little of those ambitious visions for the future are going to happen if the cost of energy is 500 or 1000 times more than the cost of that same energy here on earth.
Slashdot: So what are some implications that has when it comes to spaceflight? How does that help you to plan missions?
John: So if we had affordable and abundant energy for example in what is called the inner solar system, i.e., inside the orbit of the main belt asteroids you have abundant sunlight. If we had affordable and abundant power that we could use by harvesting that sunlight, it would make possible a wide range of very ambitious things, like developing the resources of the Moon, mining the resources of asteroids, sending people and things cheaply to destinations throughout the inner solar system—if the cost is say 10 cents or even 50 cents a kilowatt hour. If it is $500 a kilowatt hour doing any of those ambitious things is far more difficult.
Slashdot: Now when it comes to contributing to those costs, payload costs is a big reason, it is hard to put heavy things in space, are there other things that are significant too, like the availability of repair parts, what are the other factors besides the sheer payload cost?
John: Most people talk about the cost of the space transportation, it is always the thing that people talk about. People are, mostly men, are very excited about rockets, and access to space is one of the big cost drivers historically that people like to talk about. In fact, it is not usually the biggest one.
There are the big four, the biggest cost driver of doing anything in space is the cost of the space hardware itself. Because on earth, you manufacture tens of thousands to tens of millions of something, like tens of millions of personal computers, the cost per pound or the cost per kilogram comes down to $100 a kilogram, a couple of hundred dollars a pound. For space systems, where you make one, if it is just an automated system or a robot, it could be $20,000 a kilogram, $45,000 a pound. Or in the case of a human system, it could be $100,000 a kilogram---it all depends. But in any event, because you are making one or two or five, the cost per kilogram the cost of the mass of the hardware is the number one driver. Cost of access to space is also important, it tends to run something like $10,000 to $20,000 per kilogram to get to low earth orbit.
The cost of operations, i.e., how many people are involved on the ground to operate things in space is hugely important. You don’t expect to have anybody sitting back at Dell Computers or Apple standing by, to be on the phone with you for your computer, if they were there, the sustaining engineers who are on the ground some place in Texas or in California in India or China.
Slashdot: I expect there to be a call center. I don’t expect to be in space.
John: One person handles thousands of calls a day, not somebody sits standing by for your PC. In space it is the opposite, you got sustaining engineers standing by in case your system has a problem. So the cost of hardware, cost of launch, cost of operations people, cost of getting around in space. The short lifetime (I am going past four) but the short lifetimes of the systems in space. Hydroelectric power plants like Hoover Dam last for a century. A spacecraft tends to last ten to fifteen years. An aircraft lasts through thousands of flights but a launch vehicle is good for one. And so the short lifetime on this very expensive hardware, with these big ground crews, takes up a lot of money to do anything in space. You got to do something about all of these to really do ambitious things.
Slashdot: Now, the first factor you named... clearly that is a big factor, but does that get smaller as we use more commodity items? As quality of the available hardware goes up, we are not just billing just one.
John: That’s mass production. So the answer is it can come down, it can come down dramatically but it is through production, not necessarily through changing what you make it out of. If you look, for example, at a single DVD.. or Blu-Ray Disc if you prefer the different format, let’s suppose that you wanted to make a movie put it on Blu-Ray or DVD and you are only going to make one copy.. well, the cost of that material that is in the disc, it is just plastic.
Slashdot: It is not the polycarbonate, it is the factory.
John: It is everything that went into it. It is the making of the movie, the making of the content, the factory that made it, so you have to make lots of them, and even if you do make lots of them the material could either be gold and it would still cost you a few dollars, or it could be plastic and it is going to cost you a couple of cents.
Slashdot: Private space companies often talk about using commodity off-the-shelf hardware, it seems that is at least small part.
John: Well, but what they are doing there it is not so much that they are using a material that is a commodity material, they are using a piece a system that is a commercial piece, and so they are leveraging all of that production. If you can take advantage of solid state electronics that come out of consumer electronics, you don’t have to develop all of that independently, and you are leveraging all of that production that is back behind the scenes.
Slashdot: If a space program needs a... I believe... nowadays they won’t be starting from scratch.
John: Yeah, that’s true, exactly right.
Slashdot: So talk for just a moment about the future of energy in space, you mentioned solar, and solar is the obvious thing, because it is free, it is abundant, and we know how to at least get a pretty good return on solar. Are there other energy sources that are better done in space, because it seems like it is very expensive to put up even any kind of nuclear reactor.
John: Yeah. Well, on earth, there are really only two fundamental sources of energy: One is solar energy, and the other is the energy that is stored in radioactive materials inside the earth, whether it is geothermal, and it is coming from deep within the earth, it is still radioactivity inside the molten core of the earth that is bleeding to that heat, if it is near the surface then it is ore, it is mined and refined, it is uranium or what have you that is coming from the cloud out of which the solar system formed maybe 4.5 billion years ago. So those are the two fundamentals.
Slashdot: Where do you put fossil fuels in there?
John: Fossil fuels predominantly come either from past biological activities—coal and oil—or they are primordial they come from the cloud out of which the solar system formed. There has never been any biological activity on the Moon, Titan and Saturn, and yet there are hydrocarbon oceans on Saturn. All of that is primordial material. Similarly, there is natural gas on earth, which comes from biological activity, very very likely that deep within the earth there is natural gas that comes from CH4 it comes from primordial sources.
Slashdot: Let me ask you a silly question, which is Mars or the Moon, what drives you, if neither of those then what?
John: I want to answer your first question first I will come right back there on that other one. So in space there are really only two fundamental sources of energy, so it is either going to be nuclear material that you take with you from earth, or it is going to be solar energy which you harvest from the sun, and in the inner solar system, to my way of thinking, solar energy is so abundant, the source is free, the fuel is free, you have to deal with the system, but otherwise space solar power is a wildly competitive approach. Now back to the question of Moon or Mars—my personal feeling is that both are terrific goals. I have to confess that in the case of the Moon, it is three days away, six days round trip, we always know where to find it, and in terms of time, energy cost, the Moon is so much easier. So I see the Moon as the stepping stone sort of port on this the eighth continent I think it has been very nicely characterized as. It is the port from which humanity can step out into the solar system and even beyond. But I think it would be extraordinarily strange if ultimately we step out from our home not going by the way of the front porch, which is sitting there and available but rather climbing out a window. So going directly to Mars is somewhat illogical.
Slashdot: It also seems strange to go to the Moon and not have an ambition to go elsewhere.
John: Exactly. If you are not actually going to go anywhere it makes the Moon far less useful.