NASA accidentally killed life on Mars 50 years ago.
NASA killed life on Mars
The claim has been made by scientist Dirk Schulze-Makuch from the Technical University Berlin who is convinced that an experiment carried out in the 1970s that added water to the soil drowned any life on the surface of the Red Planet.
The test - known as the Viking Labeled Release experiment - did return positive for metabolism but a related investigation found no trace of organic material.
Schulze-Makuch believes that water containing a nutrient solution may have been too much liquid "and (any life) died off after a while".
In an op-ed for Big Think, the researcher wrote: "Subsequent missions have verified the presence of native organic compounds on Mars, although in a chlorinated form.
"Life on Mars could have adapted to the arid environment by existing within salt rocks and absorbing water directly from the atmosphere.
"The Viking experiments, which involved adding water to soil samples, might have overwhelmed these potential microbes, leading to their demise."