Return to the Moon

Since 1972, no one has set foot on the moon. However, there is a renewed effort for a lunar return. Why? In 1994, the orbiting Clementine probe detected radio reflections from shadowed craters at the moon's South Pole. The reflections were consistent with the presence of ice. Later, the orbiting Lunar Prospector probe detected hydrogen-rich signals form the same area, possibly hydrogen from ice.

Where could water on the moon have come from? It was probably carried to the moon by the comets, asteroids and meteors that have impacted the moon over its long history. Water was never detected by the Apollo astronauts because they didn't explore that region of the moon. If there is indeed water on the moon, it could be used to support a lunar base. The water could be split by electrolysis into hydrogen and oxygen -- the oxygen could be used to support life and both gases could be used for rocket fuel. So, a lunar base could be a staging point for future exploration of the solar system (Mars and beyond). Plus, because of the moon's lower gravity, it is cheaper and easier to lift a rocket off of its surface than from Earth.

President George W. Bush directed NASA to make plans for a return trip to the moon for resumed exploration and to possibly establish a lunar base for research and commercial applications (mining, manufacturing, tourism). The Orion Crew Exploration Vehicle is part of that effort. Besides the United States, other countries, including Japan and China, are planning to travel to the moon and researching how to build a lunar base using materials from the lunar surface. Various plans call for returning to the moon and establishing possible bases sometime between 2015 and 2035.

To learn more about the moon, take a look at the links on the next page.

Lunar Eclipses In its orbit, the moon passes between the sun and the Earth and then behind the Earth. Relative to the Earth-sun plane, the moon's orbit is slightly inclined by about 3 degrees. Occasionally, the exact alignment of sun, moon and Earth produces a solar eclipse. This happens only when the moon is in the new phase and its orbit intersects the Earth-sun plane between the Earth and the sun. The moon blocks out the sun and its shadow passes over the Earth. In the same month as a solar eclipse, when the moon is full, a lunar eclipse will occur. In a lunar eclipse, the moon passes through the Earth’s shadow, which causes its light to dim. If the moon passes through the part of the Earth’s shadow called the umbra, a total lunar eclipse will occur. If the moon passes only through the penumbra, a partial lunar eclipse will occur.