This paper provides an overview of Alpha, a rapidly developed, low-cost CubeSat mission to verify the performance of a highly retroreflective material for light-sail propulsion. Designed, integrated, and tested by students of the Space Systems Design Studio at Cornell University, this mission demonstrates a number of key technologies that enable next-generation capabilities for space exploration. In particular, this paper focuses on the novel application of ChipSats (gram scale spacecraft-on-a-chip technology) as a means of verifying Alpha's sail orbit and attitude dynamics. Other innovations include an entirely 3D-printed structure to enable quick and inexpensive prototyping, an onboard Iridium modem that bypasses the need for ground-station radio equipment, retroreflective sail material that provides more deterministic thrust from laser illumination, and an attitude-control subsystem that provides full attitude and angular-rate control using magnetorquers only. In addition to these near-term technology demonstrations, Alpha is among the first exhibitions of holography in space, a medium that shows longer-term promise in several roles for interstellar travel.

When people think of the issue of decreasing biodiversity, they generally consider pets, domestic animals, majestic beasts, and useful plants. Although many beasts and plants are threatened (pets and domestic animals are not threatened), the problem runs far deeper.

As mentioned in Chapter 3, the immutable laws of thermodynamics appear to place a limit on how well we can be stewards of our planet. To recap, the first law states that all energy is conserved. This means that no matter what you do, you cannot get more energy out of a system than you put into it. And some of that energy is inevitably wasted, which is the second law of thermodynamics. Translated into a discussion of global energy supplies, at least when we limit ourselves to discussing the energy problem and planet Earth, these two laws tell us that no matter how clever we may be, no matter how resourceful we become, no matter how hard we try, we will always waste some of the energy we consume.

Conservation, recycling, more efficient machines, altered lifestyles, and new sources of energy are all needed to reduce the growth rate of our greenhouse gas emissions. Unfortunately, the best that all of these actions combined can achieve is a reduced rate of emission growth. If humans are truly causing global warming by profligate use of fossil fuels, then we need to do far more than reduce the growth in our emissions; we must reduce the absolute amount of these gases in the atmosphere to levels below those of the last century. With more and more people entering the global middle class, and their commensurate use of more and more energy, it is unlikely, perhaps even impossible, that we will be able to stop global warming. We almost

Introduction: Welcome to the Present.- Part I: Mythical Paradise - Fire: Formation of the Earth and Solar System. The Earth Before Man: Utopia or Nightmare?- Part II: Paradise Lost? The Environmental Dilemma: Progress or Collapse? Exploding Population. Climate Change. Vanishing Life. Diminishing Energy. Humans Before the Industrial Age: A Desirable Ecological Goal?- Part III: Paradise Regained. Raw Materials from Space. Power from the Sun. Environmental Monitoring from Space. Protecting the Earth. Mitigating Global Warming. Settling the Solar System. Paradise Regained: An Optimistic Future.- Afterword: Why Space Advocates and Environmentalists Should Work Together.

There can be no question that today, one species, Homo sapiens, bestrides the world. In some circles, it is fashionable to lament this situation. Has a Golden Age been lost; has Eden been transformed into an omnipresent global civilization of commerce, popular culture, consumerism, and accumulation? Perhaps, according to some, Earth’s prime is past and the proper role of humanity is to hasten the degradation of this planet’s natural environment.