posted 02-24-2013 07:59 AM               

Space Cover #202: Life?

This cover was postmarked on July 20, 1978, the second anniversary of the first successful unmanned Mars landing by Viking 1. The postmark is from Hampton, VA where the NASA Langley Research Center developed Viking, on the first day of issue of the stamp US #Sc1759 commemorating the Viking mission. The cachet was produced by the Lyndon B Johnson Space Center (JSC) Stamp Club. The cover was also autographed by JSC scientists David S. McKay, Kathie Thomas-Keprta, and Everett Gibson. An explanation of this combination follows.

A couple of (somewhat) unrelated events this week have triggered this Space Cover of the Week. The first was the death of astrobiologist David S. McKay, and the second was the news that Curiosity has successfully drilled into a rock on Mars and will begin to analyze the drill-dust for organic compounds (potential building-blocks for life-forming chemicals).

Humans have been fascinated with the prospect of life on Mars since Schiaparelli first saw what he thought were "canals" on Mars in 1877. This evolved, in the sci-fi world, to H.G. Wells' novel "War of the Worlds" in 1898, followed by a plethora of novels and films regarding life on Mars in the 20th Century. Scientifically, the prospect of advanced life on Mars received a body-blow in 1965 when Mariner 4's 21 grainy black & white photos showed a Mars landscape almost as barren as the Moon's. But the prospect of microbial life on Mars still hung on.

In 1976 the US performed the first soft-landing on Mars with the Viking 1 and Viking 2 probes. A biological experiment on the Viking probes gave questionable results that could have been interpreted as either indicating microbial life - or not. The "life" result was mostly debunked at the time. But a re-analysis of the data, reported in 2012, gave some credence to the notion that microbial life may have actually been detected by the Viking landers. The stamp on the cover above commemorates the Viking Project.

In 1996, a meteorite found in Antarctica and confirmed to be of Martian origin, was reported to have shown evidence of fossilized microbial life. The science team consisted of the late David S. McKay, Kathie Thomas-Keprta, and Everett Gibson, who all autographed this cover at the NASA-JSC Open House on August 24, 1996. Their conclusions have since been called into question, but in the words of Dr. McKay's obituary, their paper "...sparked significant changes in Martian and planetary science, shaped the direction of the Mars Exploration Program to the present day, and prompted the establishment of the NASA Astrobiology Institute".

Since then a number of probes have landed on Mars, providing evidence of both past-and-current water deposits (another building-block for life), and providing the aforementioned credence to the Viking microbial life test results (2008 Phoenix lander, reported in 2012).

I have not consistently kept-up with Mars landing covers, so I don't have any postmarked for the water discoveries, nor for the Phoenix mission. Do any of you have some to post on this thread? I'd be glad to host the cover images if you can email them to me.

And maybe we will get to post an "Organic Materials Found!" cover for Curiosity in the near future!