Space and energy 
An open conversation with prof. Tullio Regge, on the matter of space colonization. 

TDF. We of TdF are a handful of hard astronautical-humanists (inspired by our Scientific Director Marco C. Bernasconi, we consider ourselves true astronauts, even if we never have flown in space, while others are only circumstantial astronauts) and our position pro-space is very much a radical one. Do you think that humanity has a future in space? 

REGGE. As far as the astronauts, I have known a dozen of them, our Malerba among them. Another fifty astronauts were at a ceremony, in Star City, near Moscow, for the twentieth anniversary of Sputnik, between them Leonov and Tereskova and, many years ago, in Houston. Also I saw the takeoff of the last lunar flight, Apollo 17, in Cape Kennedy. To establish human colonies in the solar system, they should be economically profitable. It would be enough to discover an asteroid made of cobalt or of some rare and very useful metal, or to find a way to pull down commercial amounts of hydrogen without devastating the environment. The current space station does not match such requirements, it is very much expensive and the research made on board could be better made by automated probes. I would explore systematically the asteroid belt, seeking the one made of pure gold (:-). 

TDF. The topic of the space Klondike is fascinating! Sure people would leave also on carts, scarcely pressurized. But we don't need to go so far away to find the gold of space (please see also The gold of the Moon). Did you never try to calculate how many GigaWatts of solar energy crosses the so-called Greater Earth (a sphere with radius 1.5 Mkm., having our planet as center, more or less the extension of the Earth's magnetosphere, to the L1 liberation point)? It has flowed, for billions of years, and will do so for as many more, whether we use it or we let it flow unused forever. Satellite power stations (we can construct how many we want, they will not waste the environment) could collect as much energy to satisfy the requirements of Earth and of all the colonies that we can envisage for next 50 years (I didn't make a precise calculations, but maybe it would be a worthwhile activity to do so). Sent to earth in the form of microwaves, stored, for instance, as hydrogen, in some decades it would be nearly free. Why do the oil producers not have enough imagination to think of themselves as energy suppliers, and to invest part of their huge patrimony in demonstrative satellite power stations? Please help us to take the idea to the home of "Mr. Agip": it would be a formidable step for the opening of the space frontier! 

REGGE. Carlo Rubbia has, -- if one may use the expression -- modestly, proposed to begin with a 50 x 50 km square of solar PV panels in Sicily, 2500 km2, i.e. 2.5 Gm2. If my calculations are right, at the cost of 400 USD/m2 we reach approximately 1000 Giga$. It is too much for my taste. I would like better to begin with a localized distribution of photovoltaic energy on Earth but not subsidized. I would simply remove the governmental bureaucratic barriers that prevent the dissemination of non-government energy. Then we will see. The idea to send down energy from space by microwaves could work, but we could never convince the greens that it is innocuous for the environment, they will always say no. I remain opposed to megaprojects: they only serve to feed tangents, creating bogus economies. If the photovoltaic technology takes root on Earth, we could then begin with a space pilot system to be gradually increased, but before that I want to see the feasibility, the rendering and many other things. I would not want the sky to be eaten by enormous purple panels. 

TDF. A satellite power station would be positioned in high orbit, at 36,000 km (advantages: it is geostationary, it covers a very large area, and others), I don't think that we could see purple panels, even if we are speaking of "sheets" of great surface area. The other classic objection, as to the supposed dangerousness of the microwaves in the atmosphere, has already been discussed and refuted. The range of the power generated by such kind of systems is from 200 to 500 Watt/m2, which is absolutely not dangerous for animals or persons, if they would be in the middle of the beam (sunlight exceeds 1000 Watt/m2). Also the center of the cone is absolutely sure, according to international standards. 
REGGE. In any case we are not speaking about space colonization, but to use the space close to the Earth, for settlement I mean places inhabited for long periods and that are distant from Earth. These kind of satellites will just continue the current tendency of economic use of the geostationary orbits. 

Prof. Regge obviously is right with this last comment. However, if we consider that satellite power stations would have to be garrisoned and maintained, and that they could also sell the energy produced to other orbital stations, the Space Photovoltaic development represents however a formidable and concrete impulse to the industrialization and inhabitation of the space. 

[AA-TR TDF 2/2001 - 31/03/2001]
[The English version was revised by Ben Croxford]