The gravity assist would allow a safe return to Earth even if the spacecraft's main rocket engine failed, Professor Longuski said.

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We can have jobs providing safe, clean, renewable energy that does destroy the earth, the waters, and the air that we breathe.

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However, the environmental group, Friends of the Earth, believes that even with better containers, OPs still will not be safe.

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Many of the technologies that NASA develops to explore the universe and keep astronauts safe in the extreme environment of space have applications right here on Earth.

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"There's lead acetate in hair dyes, lead in lipsticks, formaldehyde and 1, 4-dioxane in baby shampoos and other shampoos, " said Lisa Archer, co-founder and former director of the Campaign for Safe Cosmetics and current director for the environmental group Friends of the Earth.

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If humans ever do go to asteroids or Mars, the scale of the infrastructure needed to complete a safe round trip could not possibly be launched on a single rocket from Earth.

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On the northern side of the volcano, participants can watch lava spew out of the Earth from a tented camping site 1.5 kilometers away, which has been deemed safe by a volcanologist.

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