This view of Viking 2 shows Utopia Planitia on Mars in 1976. Some researchers believe that the Viking Landers' main instrument has burned organic molecules in collected soil could samples.
Source: NASA / JPL-Caltech
More than 40 years ago, a NASA mission may have accidentally destroyed the first discovery of organic molecules on Mars, according to a New Scientist report.
Recently NASA caused a stir when it announced that its Rover Curiosity on Mars has discovered organic molecules that make up life as we know it. This was the first confirmation of organic molecules on Mars in 201
Scientists did not know what to do with the Viking results – how could there be no organic matter on Mars? "It was just totally unexpected and out of tune with what we knew," said Chris McKay, a planetary scientist at the NASA Ames Research Center opposite New Scientist. [Viking 1: The Historic First Mars Landing in Pictures]
One possible explanation emerged when NASA's lander Phoenix 2008 found perchlorate on Mars. This is a salt that is used to make fireworks on earth. it becomes highly explosive at high temperatures. And while the surface of Mars is not too warm, the main instrument aboard the Viking lander, the Gas Chromatograph Mass Spectrometer (GCMS), had to heat the Martian soil samples to organic molecules. And since perchlorate is in the soil, the instrument would have burned any organic matter in the samples during this process.
The discovery of perchlorate revived the scientists' belief that the Viking countries could have found organic matter on Mars. "You get new insights, and you realize that everything you thought was wrong," McKay said.
However, perchlorate has not provided any concrete evidence that the Viking lander found and accidentally destroyed organic molecules, so the investigation continued.
The variety of organic molecules that Curiosity recently discovered on the Red Planet included chlorobenzene. This molecule is created when carbon molecules burn with perchlorate, so scientists suspect that it may have been produced by burning the soil samples, New Scientist said.
The researchers were inspired by this indirect evidence to dig deeper and find more evidence that the Viking countries could have found and then destroyed organic matter. In a new study published in June in the Journal of Geophysical Research: Planets, by Melissa Guzman of the LATMOS research center in France, McKay and a handful of collaborators have reviewed the Viking Lander data to see if anything has been missed.
This team found that the Viking Landers had also found chlorobenzene, which, according to the researchers, could have been caused by the burning of organic matter in the soil samples.
However, this is no proof that the Viking Landers found organic molecules and then accidentally burned them. Even the scientists who completed this study are divided.
Guzman said she still was not fully convinced that the chlorobenzene they discovered had formed when organic matter was burned on the Martian soil. She said the molecule could come from Earth with NASA equipment.
But despite this skepticism, others are convinced; "This newspaper really seals the deal," said Daniel Glavin, an astrobiologist at NASA's Goddard Space Flight Center, who was not involved in the study, New Scientist.