Martian soil become less friendly for living as perchlorate like chemical substance found in its soil.
In Earth, perchlorate found as naturally occurred or manmade substance; It found in soil and groundwater of earth. It is a highly oxidized salt and used as main ingredients in solid rocket fuel. It is also used in making of firecrackers.
The presence of such a chemically reactive compound in Martian soil would seem to make that soil less-supportive of life. Excess dose of this highly oxidized perchlorate react with thyroid hormone, which can harm fetus in womb.
It is still unclear that how much perchlorate is present in Mars soil and in which form. NASA also researching whether presence of this highly reactive substance in Mars soil is due to contamination, before launch of this space craft. Phoenix used another fuel, hydrazine.
Phoenix‘s MECA wet chemistry experiment detected the presence of perchlorate in Mars soil.
The lander mixed soil with water brought from Earth into a teacup-size beaker and stirred it. Two dozen sensors inside the beaker detect the soil’s pH and probe for traces of mineral nutrients.
The first soil test shows that the Mar soil is slightly alkaline in nature and contains magnesium, potassium, sodium and chloride. Second test revealed the presence of perchlorate.