The discovery of an unexpected chemical in Martian soil—one that is considered hazardous here on Earth—says little by itself about the possibility of life on Mars, NASA researchers announced this afternoon.

They confirmed that Phoenix Mars Lander had found evidence in soil samples of perchlorate (ClO4), a highly reactive chemical that can occur naturally on this planet in areas such as Chile's Atacama Desert, an extremely arid environment that researchers have studied as a proxy for Mars.

Researchers once believed that life could not survive the Atacama's harsh conditions, suggesting that perchlorate and life do not mix. But in fact some microbes consume it for fuel and some plants collect it the way they would nitrates, for the oxygen it stores, researchers said.

Perchlorate is toxic to people only in the sense that it can disrupt the production of thyroid hormone, an important growth hormone needed by babies in the womb for normal development.

"We have substantial evidence that our soil samples contain perchlorate," Peter Smith, lead Phoenix investigator at the University of Arizona Lunar and Planetary Laboratory (LPL) in Tucson, said during a press conference today. "In itself it is neither good nor bad for life."

The perchlorate story began last week, when AviationWeek.com reported that NASA had briefed the White House on findings related to the habitability of Mars that the agency had not disclosed in recent press briefings.

ScientificAmerican.com reported yesterday that White House Office of Science & Technology Policy, to which AviationWeek.com was referring, denied receiving any briefing.

NASA issued a statement yesterday confirming that Phoenix's wet chemistry laboratory (WCL), part of the Microscopy, Electrochemistry and Conductivity Analyzer (MECA) instrument, had discovered perchlorate in two soil samples analyzed in June and July.

WCL dissolves soil in water samples brought from Earth and then uses a series of electrodes to "taste" for ions (charged atoms) of chlorine, sodium, potassium and other elements.

Phoenix researchers said they did not announce the possible perchlorate finding because they were still trying to reconcile it with results from the Thermal and Evolved-Gas Analyzer (TEGA), which bakes samples and "sniffs" the vapors that come off for different elements.

In one TEGA test, soil released oxygen at a high temperature, consistent with perchlorate, which exists as a salt joined with another element such as magnesium or sodium. Some of these salts would also give off chlorine; a second TEGA study, however, did not detect that element. That rules out perchlorate salts of magnesium, calcium or iron, said William Boynton, lead investigator for TEGA at LPL.

The soil probably contains a mix of salts, added Michael Hecht, lead investigator for WCL at NASA's Jet Propulsion Laboratory in Pasadena, Calif.

Phoenix researchers said they also wanted to rule out the possibility that perchlorate had somehow infiltrated the experiment prior to landing on Mars. The third stage of the Delta 2 rocket that gave Phoenix its final boost to Mars burned perchlorate-based solid fuel.

Researchers said it seemed unlikely that the perchlorate had contaminated the sample in that way, given that the water Phoenix carried with it, which was used to dissolve soil in the WCL, did not show signs of the compound.

Smith said the finding caught him by surprise: "Nobody had ever mentioned the possibility of perchlorate in our soil to me."

7 Comments

1. 1. jack_sparrow 10:37 AM 8/6/08

   I do not understand why one thing is not clear to any of us! It seems obvious and logical conclusion from this find that Mars has been explored and excavated by extra-terrestrials many times and the prsence of perchlorate used in rocket fuel and explosives only confirms that.

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2. 2. Mark 07:23 PM 8/6/08

   Don't you think aliens capable of interstellar travel would be using something other than glorified gasoline (that we had invented by the 1960s) to get here?

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3. 3. John Bardakch 08:34 AM 8/7/08

   Hello.Dear NASA organization send Phoenix to Mars succesfuly.Now research examples coming to world.Maybe somebody hope life marks on this near planet.But this percholarate(CI04)is sadness.On the other hand we apricate this hard works because everybody want to leaarn about outside our planet even more Universe's deeps and far other parts 'what's going on ?'....Maybe our planet is just a little point on this panaroma but very precious.Some astronots said about world panaroma from space:"-amazing ,like a jewelery shining..."By the way not only this fantastic view but contains are marvelous.Mountains,flowers,animals,lakes,rivers,trees,vegetables,seas,oceans,islands and other many creation beauties.But unfortunately all human don't understand how much precious natural creations.Wrong using some chemicals,high populations giving vey important damages to environment .These damages are very serious and dangerous.But unfortunately some commercial ,local advanteges are big obstackles for solve these problems.Corruption and pollution will give more damages to earth.Space still are like God's make ,inoncent and clean.Universe's Creator is watching world and sadness this harmful panaroma and he will operation soon for to finish all responsible bads and badnesses.(I want to dvice to dear Scientific American's readers about this subject : www.watchtower.org )With researching activities; human will learn more creation miracles on earth and space by dear scientists hardworks.But scientists must have right targets for this researchs.Especialy goverments,international and local other science must quide them for them serious important works.This marvelous works will give many new informations to other scientists and researchers.Politic and commercial targets generaly not objective and humanist.Scientists first must belive a lovely and Almighty God .About life origin truth must be learn.Albert Einstein said personal life end years"universe created by God and we can take knowledgments about Him by watching nature and reading Bible. For example;Holy Bible first book Genesis give information about our planets creation simple but true knowledgment.This information must be basic for science.If we learn life mystries we must have respect Grand Maker.Our personal life ,world and other all universe still included many secrets.Details will show God's high wisdom and power us.W e must love all life kinds ;first self later others .We hope after God's operation everythigs will change His Holy purpose and all good (acording to His standarts) mankind.Regards

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4. 4. csacas 06:40 PM 8/10/08

   good one but what i want to know is that is there any trace of life observed out there.....now let me think something absurd..we human think that we are one of the creature on earth but it may happen that appart from human beings there are other human like creature might exist in universe who can resist the perchlorate..

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5. 5. sixtwoandeven 12:19 AM 8/11/08

   The discovery of perchlorates at the Phoenix site is significant for serveral reasons. First, since perchlorate salts dissolve easily in liquid water, it suggests that the water discovered as ice at the site has been in a frozen state for a very long time - allowing the perchlorate to accumulate. Second, it demonstrates that the soil at the site is chemically active, since perchlorates can form when certain other, naturally occurring salts are exposed to ultraviolet light. Lastly, and most importantly for a future manned mission to mars, perchlorates can be used to make rocket fuel. Since current plans for a manned Mars mission would require the astronauts to manufacture enough rocket fuel on Mars for the return to Earth, finding perchlorates is a very good thing.

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6. 6. zetalimit 07:28 AM 8/11/08

   it's walking but did you check from night time static build up on those nano chips

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7. 7. zetalimit 07:36 AM 8/11/08

   I^mz .... I = infinite ^ angle of mz = largest and smalles measurement programmed ga programming infinite global var; this works with a-z in science like earth = e3 = mc

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