Nos anos 70, astronautas da Apollo trouxeram para a Terra cerca de 400 kgs de rocha da Lua. Quinze anos depois, cientistas da Universidade de Wisconsin descobriram quantidades significativas de hélio-3, um isótopo estável de hélio, na superfície lunar.
Este tipo de hélio-3 tem uma característica: falta-lhe um neutrão e, com isso, pode ser usado em reactores de fusão nuclear para produzir energia limpa. O problema é que as fontes abundantes deste isótopo estão a milhões e milhões de quilómetros de distância, na Lua.
Os reactores nucleares actuais usam reactores de fissão, dividindo núcleos de urânio para a libertação de energia. Este calor transforma água no vapor que move turbinas para a produção de electricidade. Infelizmente, a radioactividade é um subproduto desta reacção, assim como o combustível perdido reprocessado em urânico e plutónio e o lixo radioactivo.
Segundo a Environmental News Network, os cientistas estão a estudar numa forma alternativa, a energia de fusão nuclear. É aqui que entra o hélio-3 que, como combustível deste tipo de reacção, pode fornecer energia sem radioactividade e subprodutos nucleares.
Os reactores de fusão alimentados por tritio e deutério – ambos isótopos do hélio – perdem mais energia do que produzem, tornando-os fontes pobres de produção de energia. Mas as reacções de fusão com hélio-3 e deutério, que criam o hélio normal e um protão sem um neutrão, perdem menos energia. Mas é o protão que importa: manipulá-lo em um campo eléctrico produz energia. O processo de fusão com o hélio-3 tem eficiência de 70% se comparada ao carvão e gás natural, que têm eficiência de apenas 20%.
O problema é que toda a reserva de hélio-3 dos Estados Unidos não chega aos 40 kgs, quando um País desse tamanho precisaria de, pelo menos, 25 toneladas por ano.
Há uns dias li aqui que Larry Page e James Camaeram iriam começar a exploração asteróides para extracção de metais preciosos, através da empresa Planetary Resources.
A Planetary Resources acredita que o acesso a estes metais vai aumentar, baixando o custo de numerosos equipamentos, desde a microeletrónica às baterias, e emergindo novas aplicações.
A empresa crê ainda que os asteroides próximos da Terra, que contêm muita água sob a forma de gelo, poderão servir de espécie de oásis às missões de exploração espacial mais distantes, ao fornecerem fontes essenciais de água e carburante, tornando assim as viagens mais económicas.
A Planetary Resources tenciona colocar, dentro de dois anos, em órbita terrestre telescópios espaciais para definir a posição dos asteroides mais promissores. Depois, lançará pequenos engenhos espaciais para os explorar. As atividades mineiras propriamente ditas começarão nos asteroides mais ricos em água e platina.
A ideia de explorar as riquezas dos asteroides não é nova e remonta pelo menos a 1926, com um projeto teórico do cientista russo Konstantin Tsiolkovsky. Contudo, a Planetary Resources está a formar um novo paradigma na utilização de recursos que trará o sistema solar para a esfera de influência enconómica da humanidade ao disponibilizar uma exploração robótica de baixo custo e evetnual comercialização de asteróides.
Apesar de todas as dificuldades que a ideia apresenta, verdade seja dita, iremos beneficiar em muito caso esta nossa odisseia espacial chegue a bom porto. Os recursos mineiros terrestres são limitados e as reservas na Terra estão a ser utilizadas num ritmo avassalador pela cont+inua exploração, causando problemas de sustenbilidade de recursos a longo prazo. Esta ideia, apesar de não ser pioneira, abre portas a uma reserva infinita de minerais.
A exploração mineira inter-planetária irá permitir a criação e o desenvolvimento de novas indústrias, criação de novos postos de trabalho, etc.
Por fim, deixo aqui uma sugestão de leitura. Não é recente, mas é boa para quem quer saber mais sobre este tópico.
AS we face $4.50 a gallon gas, we also know that alternative energy sources — coal, oil shale, ethanol, wind and ground-based solar — are either of limited potential, very expensive, require huge energy storage systems or harm the environment. There is, however, one potential future energy source that is environmentally friendly, has essentially unlimited potential and can be cost competitive with any renewable source: space solar power.
Science fiction? Actually, no — the technology already exists. A space solar power system would involve building large solar energy collectors in orbit around the Earth. These panels would collect far more energy than land-based units, which are hampered by weather, low angles of the sun in northern climes and, of course, the darkness of night.
Once collected, the solar energy would be safely beamed to Earth via wireless radio transmission, where it would be received by antennas near cities and other places where large amounts of power are used. The received energy would then be converted to electric power for distribution over the existing grid. Government scientists have projected that the cost of electric power generation from such a system could be as low as 8 to 10 cents per kilowatt-hour, which is within the range of what consumers pay now.
In terms of cost effectiveness, the two stumbling blocks for space solar power have been the expense of launching the collectors and the efficiency of their solar cells. Fortunately, the recent development of thinner, lighter and much higher efficiency solar cells promises to make sending them into space less expensive and return of energy much greater.
Much of the progress has come in the private sector. Companies like Space Exploration Technologies and Orbital Sciences, working in conjunction with NASA’s public-private Commercial Orbital Transportation Services initiative, have been developing the capacity for very low cost launchings to the International Space Station. This same technology could be adapted to sending up a solar power satellite system.
Still, because building the first operational space solar power system will be very costly, a practical first step would be to conduct a test using the International Space Station as a “construction shack” to house the astronauts and equipment. The station’s existing solar panels could be used for the demonstration project, and its robotic manipulator arms could assemble the large transmitting antenna. While the station’s location in orbit would permit only intermittent transmission of power back to Earth, a successful test would serve as what scientists call “proof of concept.”
Over the past 15 years, Americans have invested more than $100 billion, directly and indirectly, on the space station and supporting shuttle flights. With an energy crisis deepening, it’s time to begin to develop a huge return on that investment. (And for those who worry that science would lose out to economics, there’s no reason that work on space solar power couldn’t go hand in hand with work toward a manned mission to Mars, advanced propulsion systems and other priorities of the space station.)
In fact, in a time of some skepticism about the utility of our space program, NASA should realize that the American public would be inspired by our astronauts working in space to meet critical energy needs here on Earth.
O. Glenn Smith is a former manager of science and applications experiments for the International Space Station at NASA’s Johnson Space Center.
It’s language and imagery that would make a space advocate’s mouth water. In a television ad released last month by the campaign of presumptive Republican presidential nominee John McCain last month, a narrator intones, “American technology protected the world. We went to the Moon not because it was easy, but because it was hard.” On the screen, there is a matrix of images: an early satellite, a Saturn 5 lifting off, an astronaut on the surface of the Moon. Was a major presidential candidate really talking about space in a campaign ad?
Well, not exactly. “John McCain will call America to our next national purpose: energy security,” the narrator continued. The imagery on the screen changed: the rocket and astronaut were replaced by a gas pump, oil well, and windmills as the narrator talked about McCain’s plan to reduce gas prices, increase domestic oil production, and promote alternative energy sources. Energy quite literally pushed space out of the picture.
The real area of concern for space advocates, though, is the growing argument that a major national initiative is needed to deal with high energy prices and growing global demand.
This fixation on energy is neither partisan nor surprising. Skyrocketing oil prices, and the resulting sharp increases in the price of gasoline—the national average is now over four dollars a gallon, and approaching five dollars a gallon for some grades in some regions—have put energy front and center in the minds of many Americans. Hardly a day goes by where you don’t hear about some effect these high prices are having on the economy and on the way of life, from increased ridership of mass transit systems to sluggish sales of gas-guzzling SUVs to the precarious financial state of the airline industry.
So what does any of this have to do with space? The connection between high gas prices and spaceflight isn’t obvious at first. Yes, higher oil prices do increase costs for space products and services, just as they do for virtually every other industry. However, unlike the airline industry, where fuel is a significant fraction of overall costs, spaceflight is not nearly as vulnerable to swings in prices: the fuel that used by a typical launch vehicle is a tiny fraction of the overall cost of launch services—and some vehicles, like the space shuttle, don’t use petroleum-derived fuels at all in favor of alternatives like liquid hydrogen.
The real area of concern for space advocates, though, is the growing argument that a major national initiative is needed to deal with high energy prices and growing global demand. It’s an argument that not only both major presidential candidates have made, but one where they have invoked perhaps the holiest of accomplishments in the eyes of space enthusiasts—the Apollo program—as their model and justification. In addition to the television ad, McCain invoked Apollo in a speech last month in reference to a goal of his proposed energy policy to achieve “strategic independence” by 2025. “Some will say this goal is unattainable within that relatively short span of years—it’s too hard and we need more time,” he said. “Let me remind them that in the space of half that time—about eight years—this nation conceived and carried out a plan to take three Americans to the Moon and bring them safely home.”
The presumptive Democratic nominee, Barack Obama, has also not shied away from linking the Apollo program to energy policy. “Only one candidate has a detailed plan that is at Apollo moon-mission scale, using technologies that work right now—Barack Obama,” reads a passage in the energy policy section of Obama’s campaign web site. That document also calls for an “Apollo-scale investment” of $150 billion over 10 years “to jumpstart renewable energy technology development and deployment.”
Obama has also used Apollo to differentiate his energy proposals from those by McCain. After McCain put forward last month a $300-million prize for improved car battery technology, Obama struck back in a speech in Las Vegas. “But I don't think a $300 million prize is enough. When John F. Kennedy decided that we were going to put a man on the Moon, he didn’t put a bounty out for some rocket scientist to win—he put the full resources of the United States government behind the project and called on the ingenuity and innovation of the American people. That’s the kind of effort we need to achieve energy independence in this country, and nothing less will do.” (A number of space advocates have noted, in response, things like the Ansari X Prize, Google Lunar X Prize, and NASA’s Centennial Challenges program as examples of space prize competitions, albeit far from the scale of human lunar exploration.)
“When John F. Kennedy decided that we were going to put a man on the Moon, he didn’t put a bounty out for some rocket scientist to win—he put the full resources of the United States government behind the project and called on the ingenuity and innovation of the American people,” Obama said, criticizing McCain’s battery prize proposal.
Outside the presidential campaign, many others have invoked Apollo as the model to use for a new national energy program in newspaper editorials and op-eds. In a June 29th editorial in The Spectrum and Daily News of St. George, Utah, editor Todd Seifert mentioned Apollo—fresh in his mind after seeing the recent Discovery Channel documentary series “When We Left Earth”—in connection with energy policy. “It’s astonishing to think that we could land a man on the moon in eight years’ time about 40 years ago but can’t accomplish another important endeavor: shift from oil as a primary fuel source,” he wrote. “Sure, it’s going to take commitment. But it’s that commitment—like we made to the space program to land a man on the moon decades ago—that we desperately need as a nation.”
A similar argument was made in a July 6th op-ed in The Tennessean of Nashville by Preston MacDougall, a chemistry professor at Middle Tennessee State University. “It seems to me that the sky-high price of gasoline has had an effect on Americans today that is similar to what Sputnik’s overhead flight did in October 1957,” he wrote. “People have been surprised by it, and feel insecure even though a beeping fuel pump does not physically threaten them. They want the government to do something that solves the problem without creating bigger ones.”
MacDougall argued that what was needed was a comprehensive government energy policy, as opposed to half-measures and forgotten goals. Recalling President Kennedy’s May 1961 announcement of the goal of sending humans to the Moon by the end of the decade, MacDougall writes, “This goal wasn’t just thrown into an annual State of the Union speech, later to be forgotten, like President Bush’s plan to return to the moon by 2020 as a steppingstone to Mars.”
For the space community, this appropriation of Apollo to promote energy policy might seem harmless enough, if a little annoying, much like the old line, “If we can put a man on the Moon, why can’t we…” followed by any number of things. However, there is a hidden threat in the use of such language. A comprehensive “Apollo-like” energy policy will come with an Apollo-like price tag: Obama’s alternative energy proposal, for example, works out to an average of $15 billion a year: over 85 percent of NASA’s current budget. Where is that money going to come from?
Given that both major presidential candidates have promised to reduce current budget deficits, it’s likely that at least some money for an Apolloesque energy program would have to come from other parts of the federal budget. Could that include space? Possibly. As one space activist recounted, Obama suggested on the campaign trail earlier this year that alternative energy, and not space, “is what our next Apollo Program should be.” (see “Obama’s modest proposal: no hue, no cry?” The Space Review, April 7, 2008)
A common reaction from space advocates is to argue that NASA can be part of the solution to the nation’s energy programs, noting that the agency has pioneered alternatives like fuel cells and solar power. However, relying on spinoffs is a haphazard strategy, at best, and having a dedicated energy technology program within NASA would likely only take money away from the agency’s core space technology efforts.
Another common response, of course, is to cite the promise of space solar power (SSP). And, indeed, SSP could go a long way towards solving the nation’s energy woes—in theory. The problem is that even supporters of SSP acknowledge turning that theory into reality is still decades away, assuming that technological and financial obstacles can be overcome: little comfort for those feeling pain at the pump today. Moreover, others are less sanguine about SSP’s prospects (see “Knights in shining armor”, The Space Review, June 9, 2008).
Pit hed-to-head against each other, it’s almost certain that pnding on the development of alternative, cheaper sources of energy would beat out spending on space exploration in the minds of the general public.
This is not the first time that the US or the world has experienced an energy crisis. However, this time around the fundamentals are different: supply is not artificially constrained by an embargo; instead, demand for oil is growing dramatically thanks to economic growth in developing nations, particularly China and India. Coupled to that are concerns about relying on oil from unstable or otherwise undesirable parts of the world (the Middle East, Venezuela), as well growing concern about climate change and fossil fuels’ role in it. Combined, this all suggests that this is not a repeat of the 1970s but instead a permanent change that, without action, will only get worse, not better, over time. That makes it all the more likely that we will see some kind of new energy initiative by the federal government, be it Apollo-like in scale or smaller.
Pit head-to-head against each other, it’s almost certain that spending on the development of alternative, cheaper sources of energy would beat out spending on space exploration in the minds of the general public. Fortunately for the space community, public policy isn’t made that way, but new energy policies will add to the existing fiscal pressures on NASA and space exploration in the next administration and beyond. That makes it all the more imperative for NASA and its supporters to craft approaches that are cost effective and also exciting and inspiring, to help win public support and thus funding. Otherwise, the Vision for Space Exploration and efforts like it might run out of gas.
Jeff Foust (email@example.com) is the editor and publisher of The Space Review. He also operates the Spacetoday.net web site and the Space Politics and Personal Spaceflight weblogs. Views and opinions expressed in this article are those of the author alone, and do not represent the official positions of any organization or company, including the Futron Corporation, the author’s employer.