The Earth. There’s no place like it, at least that we know of.

It’s that very sense of awe that prompted Gaylord Nelson, a nature loving Wisconsin political activist, to begin a grass roots campaign to raise the public awareness for an environment at peril with an annual observance.

April 22 will mark the 40th anniversary of the first Earth Day, Nelson is widely credited with initiating. The observance has since spread to 190 countries where there are new concerns for the global warming and a growing interest in protecting the environment with energy efficient policies as well as programs that promote preservation and advance a greener economy.

No where is the fragile nature of the Earth and its ability to support the 6.8 billion people who inhabit the planet more apparent than from space.

“If we could get more people on the Earth up into space to see the beautiful planet, I don’t think it would be so difficult for so many of us to live together,” NASA astronaut Clay Anderson told a gathering of North Carolina school students during shuttle Discovery’s April mission. “My hope is that more people will get that opportunity. It would change everyone’s perspective about how we view our planet and the people on it.”

For decades, NASA developed satellites have kept vigil on the weather, helping the National Weather Service and TV weather forecasters tell us when to evacuate for a hurricane or pack the car for a sunny day at the beach.  More recently, spacecraft pioneered by NASA have begun studying long-term changes in the atmosphere, the oceans and land masses, observations that are revealing how much our every day activities as humans impact the environment and climate.

Astronauts as well have been turning their cameras toward the Earth since the pioneering Mercury missions of the early 1960s.  The Earth is constantly changing. And many of those changes have been documented by camera toting U. S. astronauts from the Apollo, Space Shuttle and International Space Station eras.

The Gateway to Astronaut Photography of the Earth, a searchable collection, now numbers will over 900,000 images.  The growing collection offers scientists a sort of “fossil record” record of how the planet has changed while under the watchful eye of those who with the best vantage point.

While serving as a long running Earth observation platform for astronauts, the International Space Station has evolved into the world’s first green spacecraft. The U.S, Russian, European, Japanese and Canadian astronauts who share the outpost recycle their breathing air. They recover drinking water from the moisture in the air as well as their urine. Those crucial life support systems rely on electricity generated with sunlight. More of these green energy innovations will be necessary if future generations of explorers are to travel to exciting and ever more distant destinations.

Earlier this month, NASA brought some of its green energy achievements in space down to Earth, as it christened a new 10 megawatt solar power plant located at the Kennedy Space Center in Florida. The plant, developed in a partnership with Florida Power & Light, supplies enough electricity for 1,000 homes. At the same time, the solar power plant is off setting the atmospheric release of 227,000 tons of carbon dioxide, a contributor to global warming, annually.

“NASA is a pioneer in the use of solar power for space exploration,” said Bob Cabana, Kennedy’s director. “This type of commercial partnership with NASA helps provide Florida residents, and America’s space program, with new sources of green power that reduce our reliance on fossil fuels and improve the environment.”

To learn more about upcoming Earth Day events, visit: http://www.nasa.gov/topics/earth/earthday/index.html