By Paul D. Spudis
Tuesday, December 27, 2005
The recent release of the details of NASA's proposed plans for human return to the moon in response to President Bush's "Vision for Space Exploration" last year has drawn much comment -- some positive, some negative and some simply perplexed.
Although the reasons for undertaking the program were clearly articulated in the president's speech, it is important to reexamine why the moon is its cornerstone and what we hope to achieve by returning there.
The moon is important for three reasons: science, inspiration and resources. All three are directly served by the new lunar return architecture. This program has the potential to make significant contributions to our national economy and welfare.
The moon is a scientific laboratory of extraordinary facility, richness and benefit. The history of our corner of the solar system for the past 4 billion years is preserved and readable in the ancient dust of the lunar surface. This record is lost on the dynamic and ever-changing surface of Earth. Other planets do not record the same events affecting Earth and the moon, including impacts, space particles and the detailed history of our sun. The recovery of this record will let us better understand the impact hazard in the Earth-moon system as well as unravel the processes and evolution of our sun, the major driver of climate and life on Earth.
The moon is a stable platform to observe the universe. Its far side is the only known place in the solar system permanently shielded from Earth's radio noise. That allows observation of the sky at radio wavelengths never before seen. Every time we open a new spectral window on the universe, we find unexpected and astounding phenomena; there is no reason to expect anything different from the opening of new windows on the universe from the surface of the moon.
The moon is close in space (only three days away) yet a separate world filled with mysteries, landscapes and treasures. By embracing the inspiring and difficult task of living and working there, we can learn how to explore a planetary surface and how the combined efforts of both humans and machines can enable new levels of productive exploration.
In 21st-century America, our existence depends on an educated, technically literate workforce, motivated and schooled in complex scientific disciplines. Tackling the challenges of creating a functioning society off-planet will require not only the best technical knowledge we can muster but also the best imaginations. One cannot develop a creative imagination, the renewable resource of a vibrant society, without confronting and surmounting unknowns and challenges on new frontiers.
Although of fairly ordinary composition, the moon contains the resources of material and energy that we need to survive and operate in space. With its resources and proximity to Earth, the moon is a natural logistics and supply base, an offshore island of useful commodities for use there, in space and ultimately back on Earth.
Water is an extremely valuable commodity in space -- in its liquid form, it supports human life, and it can be broken down into its two components, hydrogen and oxygen. These elements make the highest-energy chemical rocket propellant known. Water exists in the dark and cold regions near the poles of the moon. Scientists estimate that each pole contains more than 10 billion tons of water, enough to launch a fully fueled space shuttle once a day, every day, for over 39 years. The ability to make fuel on the moon will allow routine access to Earth-moon space, the zone in which all of our space assets reside.
The moon's slow rotation, unclouded skies and abundant local materials make it possible to build installations specifically designed to harvest solar energy there. Solar power, collected on the moon and beamed to Earth and throughout the space between the two, can provide a clean and reliable energy source not only for space-based applications but ultimately for users on Earth as well. Lunar solar power solves the apparent "showstopper" of other space-based solar power systems -- the high cost of getting the solar arrays into space. Instead of launching arrays from the deep gravity well of Earth, we would use the local soil and make hundreds of tons of solar panels on the moon.
Living on the moon will expand the sphere of human and robotic activity in space beyond low-Earth orbit. To become a multiplanet species, we must master the skills of extracting local resources, build our capability to journey and explore in hostile regions, and create new reservoirs of human culture and experience. That long journey begins on the moon -- the staging ground, supply station and classroom for our voyage into the universe.
The writer is a lunar scientist and staff member at the Johns Hopkins University Applied Physics Laboratory. Last year he served as a member of President Bush's Commission on the Implementation of U.S. Space Exploration Policy.