A wakeup call for non-violent
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Low-cost space accessAlthough solar cells and many other technical innovations may help to mitigate our environmental problems, ultimately the pressures of population growth and economic growth will overwhelm us unless more radical steps are taken.
Human presence in outer space began in the 1950's and 1960's, with the development of a capability to carry out spectacular exploratory adventures at fantastic expense. Unfortunately, it eventually became clear that the primary motivation for the heroic era of the Apollo moon missions was nothing more than cold war sabre rattling. By the end of the 60's many people became disillusioned with the NASA space program. The conventional wisdom held that because of the fantastic expense of access to outer space, it would remain an exotic realm remote from the needs and practicalities of earthly life.
The time has come to re-evaluate that conventional wisdom.
In his book "The Millennial Project" (an intriguing mix of science and over-optimism verging towards science fiction), Marshall Savage wrote:
"Our situation is analogous to yeast in a bottle. The yeast cells will double their number every day until the bottle is full -- then they will all die. If the yeast die on the 30th day, then on what day is the bottle half full? The 29th day. We are in the 29th day of our history on Earth. We must do something now, or face extinction."
"The obvious answer is to blow the lid off this bottle! We need to rupture the barriers that confine us to the land mass of a single planet."
As Savage points out, the amount of energy required to send a pound of mass into orbit (if perfect efficiency could be achieved) is less than 5 kwh, or about 20 cents' worth. Existing rockets achieve fuel efficiencies around 1%, as well as requiring the destruction of much or all of the launch craft with each flight. (Even the Space Shuttle destroys its two solid rocket boosters with each mission, as well as requiring extensive refurbishment amounting to complete replacement of some subsystems.) This is why sending a payload to orbit currently costs around $10,000 per pound. Few people could afford even to ride a bicycle if a new vehicle had to be purchased for each trip.
Savage observes that launch systems involving mass drivers and ground-based laser propulsion could achieve energy efficiencies close to 30%, making it possible to send satellites into orbit for an energy cost of around fifty cents per pound. These launch systems would be completely re-usable, allowing their capital cost to be amortized over many missions.
While these remarkable efficiencies remain a possibility for the future, even at this moment we are on the threshold of a major advance in the accessibility of outer space. Because of progress in materials technology and rocket engine design, it's now feasible to build re-usable SSTO (Single Stage to Orbit) systems like the Lockheed VentureStar. These rockets should bring the cost for payload to orbit from over $10,000 per pound to under $1000. Eventually, SSTO technology could achieve launch costs as low as $100 per pound.
This reduction of costs will drive a cycle of innovation in space-based services, and the drive to profit will become an increasingly important factor. During the 60s and 70s the profit motive operated only indirectly among government contractors; ultimately, little or no economically tangible and valuable goods or services were produced, so the financial objective was primarily to gain the maximum possible level of government funding. Now, during the 1990's, communications services are supplying a powerful profit motive for space development. With the prospects for rapidly dropping costs, many new innovative products and services will undoubtedly emerge in the future.
Space colonizationLooking farther into the future, robotic systems may go to mine the near earth asteroids and the moon. The asteroids are rich in basic raw materials such as steel, aluminum and water. Ultimately, robotic manufacturing systems using asteroidal materials may construct the first self-sustaining habitats for humans in space, with full shielding from cosmic rays, artificial gravity, and closed eco-systems. These are the space colonies envisioned by Gerard O'Neill of the Space Studies Institute in his classic book "The High Frontier", as shown in the illustration of the colony "Island One" shown below. Mark Prado has posted a very informative website about asteroidal and lunar materials utilization at PERMANENT, and a Nasa perspective is at this link: Using Space Resources (NASA) .