Jay Gallentine is a historian and filmmaker who has spent more than ten years researching the history of unmanned spaceflight. He is the author of Infinity Beckoned: Adventuring Through the Inner Solar System, 1969–1989 (January 2016) and Ambassadors from Earth: Pioneering Explorations with Unmanned Spacecraft (Nebraska, 2009), winner of the 2009 Eugene M. Emme Award for Astronautical Literature. Both books are in the Outward Odyssey Series. 

This week in the news NASA announced that it had found liquid water on Mars. The announcement brings to mind a saga which began many years ago.

Way back in 1976, the United States did something that seems to have been largely forgotten: it landed two ships on the surface of Mars. They were called Viking 1 and Viking 2.

Along with measuring temperatures, wind speed, and other such everyday kinds of readings, the twin spacecraft tested for life on the surface of another world.

Such a test is hardly an easy thing to do. What everyone seems to want as proof of life is an astronaut (or a robotic claw) holding some form of wiggling critter. But wiggles don’t necessarily indicate that something is alive. My American flag wiggles in the outdoor breeze, but isn’t alive and doesn’t come when called. As such, Viking experimenters were forced to utilize much less glamorous methods. One of the experiments looked at how gases in a small chamber changed over time once Martian dirt had been added. Drops of liquid food could be splashed onto the dirt to see if that helped things along—or hindered them. Another experiment treated soil samples with bright light and carbon dioxide to see if photosynthesis, or maybe another process like it, might be happening up there on the Red Planet. And then a third experiment dripped its own recipe of liquid food onto Martian soil that had been dumped into a small compartment deep within Viking’s belly. The food—water, sugar, vitamins—had been spiked with radioactive glucose. If anything in the soil ate that food, it would essentially breathe out radioactive carbon dioxide gas,which could be detected by a Geiger counter hovering overhead.

The first two experiments were subject to wide interpretations, although one of them did repeatedly indicate that life was present (until it started malfunctioning and threw its results into question). The third experiment, however, worked perfectly. When the liquid food went on the dirt, the Geiger counter started singing. When the dirt was heated to hundreds of degrees, for hours at a time, the Geiger counter stayed quiet—indicating that whatever had been in the dirt had succumbed to the heat (which was the idea). When the dirt was heated only a little, the Geiger counter sang its tune only a little. And by the time both Vikings cashed it in, the experiment had given consistent results from two separate landers in different places.

At the time, the inventor of this third experiment wondered aloud why people weren’t concluding that life was present on Mars. He’d met all of the pre-launch criteria for finding it. Well, said the detractors, there are a number of reasons why we still can’t say there’s life on Mars. One is that another instrument aboard the Vikings had failed to find any organic compounds on the planet.

Another reason was that Mars is simply too cold to have liquid water on it. The detractors wondered how reliable the third experiment could be when it used liquid water as a basis for food and there’s no way liquid water could be present on the surface of Mars?”

Well, 2015 has been a good year for the man who invented that third experiment. Using the Mars rover Curiosity, researchers have confirmed that Mars does indeed have organic compounds on it. Maybe the Vikings weren’t in a good place to look, or maybe the equipment wasn’t as good back then. Organics are there, nonetheless.

And then this week, on September 28^th, the affirmation came forth that Mars does indeed have liquid water flowing on its surface. I can’t help but think that that third experimenter, who is fortunately still alive today, must feel that a major barrier has come down—a barrier to his claim of finding life on Mars.

-Jay Gallentine