Alien hunters and UFO enthusiasts get excited by the mere though of finding extraterrestrial life some day. However, there are hundreds of contamination risks associated with such space missions conducted by NASA and other space agencies around the world.

Sending astronauts to Mars or Jupiter in search of alien life sounds fancy. However, considering the variety of organisms with extreme capabilities that Earth harbour, there are huge chances that the astronauts may end up contaminating the environment of the celestial body in question.

According to Daily Galaxy, some form of microbial life from the Earth may be able to multiply and divide quickly in the hospitable environment of the other planets. As a result, the astronauts may notice a "false positive" for extraterrestrial life, which is actually Earth's own life form invading the other planet or moon.

However, it is not the only thing that concerns the research team. Cassie Conley, head of NASA's Office of Planetary Protection, believes that the other way around is also possible. Consley says that it is the responsibility of the American space agency to ensure that backward contamination is not a possibility.

That is, alien life from extraterrestrial world should not be able to reach back on Earth along with the samples collected by the astronauts. There is a huge possibility that alien life may reside themselves in the body of the astronauts returning back on Earth, and hence contaminate Earth's original life form.

The Outer Space Treaty of 1967 signed by different countries involved in space mission is major effort made in the direction of contamination prevention, according to National Geographic. It has a draft of guidelines that each space agency must follow to reduce extraterrestrial contamination, according to the type of mission that it is conducting.

NASA has also developed strong guidelines to make the best use of its existing anti-germ warfare. The components of a mission are assembles carefully in a closed room and thoroughly cleaned with alcohol. The parts are baked to kill all the spores. In addition, special care is taken to land the spacecraft in a location which is far away from the possibly "hospitable" surfaces.