The 1976 Viking Mission to Mars obtained clear positive response of the existence of Martian life that was accidently killed during the experiments, suggests new media reports.
The report released on 14 April, 2012 suggests that the robotic mission that was initiated 30 years ago may have found carbon-based chemical building blocks of life.
In the year 1976, Nasa sent two space probes, Vikings 1 and 2, to Mars to find out if life existed in the red planet.
At the time of the Vikings research, organic chemicals such as chloromethane and dichloromethane chlorine compounds were identified in the Martian soil.
Though the compounds were thought to be contaminants from cleaning fluids, further studies indicated the presence of the chemical perchlorate which was a surprise finding.
The presence of the chemical itself suggests the presence of life forms in Mars. Although the chemical is harazrdous to humans, some form of microbes consumes it for fuel.
"Our results suggest that not only organics, but also perchlorate, may have been present in the soil at both Viking landing sites," said the study's lead author, Rafael Navarro-González of the National Autonomous University of Mexico, Mexico City.
The National Geographic reported that a number of control experiments were also performed, including heating some Mars soil samples to different temperatures and isolating other samples in the dark for months. These conditions would normally kill microbes that are photosynthetic or that rely on photosynthetic organisms for survival.
The experiment proved to be successful at that time as the tests were found to be positive while the control experiments came out negative.
However, the possibility of finding Martian life was dismissed as further experiments done came out negative for life.
Currently, a team of experts using modern technology is reassessing the findings that were earlier collected during the Viking probes.
"I'm 99 percent sure there's life there. To paraphrase an old saying, if it looks like a microbe and acts like a microbe - then it probably is a microbe," DNA, an Indian daily quoted Biologist Joseph Miller, of the University of Southern California saying.
The team headed by Miller initiated a mathematical test wherein the Viking's LR data was analysed to separate biological signals from non-biological signals, Miller's team believes that the LR experiments did indeed find signs of microbial life in Martian soil.