This can well be an interesting plot to make a sci-fi movie. As the scientific community gears up for a manned mission to Mars, there are apprehensions about invaders to the red planet — in the form of micro-organisms from the Earth!
Astronomers fear that organisms on an exploring spacecraft or a landing vehicle have the potential to contaminate Mars. This would make it difficult for scientists to determine whether a life form existed on another planet or was introduced there by explorers.
Currently, spacecraft landing on Mars or other planets where life might exist must meet requirements for a maximum allowable level of microbial life. “If you are able to reduce the numbers to acceptable levels, a proxy for cleanliness, the assumption is that the life forms will not survive under harsh space conditions,” explained Kasthuri J Venkateswaran, an Indian-American researcher with the biotechnology and planetary protection group at NASA’s Jet Propulsion laboratory. That assumption may not hold up as recent research has shown that some microbes may use various protective mechanisms to survive interplanetary flights.