On Monday, Space Shuttle Atlantis blasted off from Florida's Kennedy Space Center, carrying with it, six astronauts, 30,000 pounds of pumps, numerous tanks of nitrogen, ammonia, oxygen and . . . . . . . 4,000 slithery worms!

The 'guest' astronauts have been taken to participate in a study to determine how Astronauts build and lose muscles, while they are in orbiting in Space.

The Nematode worms, which were collected from a garbage bin in Bristol, London were chosen because experts believe, that they make the perfect substitutes for studying why humans beings lose muscle when exposed to weightlessness.

The creatures, which traveled in special cell culture bags, will be tested in the weightless conditions inside Japan's Kibo laboratory, for four days, after which they will be frozen, until the shuttle returns, the day after Thanksgiving. Once back on Earth, the effect on their muscles will be tested at a clinical research laboratory in Derby.

This is not the first time worms have been fortunate enough to be included in a Space mission - They have been on four other missions, the last one in 2003, aboard the Columbia Space shuttle, which perished upon re-entry to the Earth - The worms were the only survivors!

The microscopic Nematode worms are sometimes described as the most 'numerous' animals on Earth. While over 80,000 species of these worms have been discovered, scientists believe there may be as many as 1 million species! They are also the most adaptable of any species known, and can be found in oceans, in the arctic, in the soil, and also living as parasites inside animals and plants.