https://www.theverge.com/2017/8/15/16145668/eclipse-nasa-balloons-stratosphere-bacteria-life-mars
Why NASA is sending bacteria into the sky on balloons during the eclipse
Aug 15, 2017
As the Moon blocks the Sun’s light completely next week in a total solar eclipse, more than 50 high-altitude balloons in over 20 locations across the US will soar up to 100,000 feet in the sky. On board will be Raspberry Pi cameras, weather sensors, and modems to stream live eclipse footage. They’ll also have metal tags coated with very hardy bacteria, because NASA wants to know whether they will survive on Mars.
Every time we send a rover to the Red Planet, our own microorganisms latch on to them and hitch a ride across space. What happens to these bacteria once they’re on Mars? Do they mutate? Do they die? Or can they continue living undisturbed, colonizing worlds other than our own? To answer these questions we need to run experiments here on Earth, and the eclipse on August 21st provides the perfect opportunity.
“I said, oh my god, that’s like being on Mars!”
The balloons are being sent up by teams of high school and college students from across the US as part of the Eclipse Ballooning Project, led by Angela Des Jardins of Montana State University. When Jim Green, the director of planetary science at NASA, first heard that over 50 balloons were being flown to the stratosphere to live stream the eclipse, he couldn’t believe his ears. “I said, oh my god, that’s like being on Mars!” Green tells The Verge. NASA couldn’t pass on the opportunity.
The upper part of the Earth’s stratosphere — just above the ozone layer — is very much like the surface of Mars: it’s about minus 35 degrees Fahrenheit, with very rarified air, and it’s hammered by the Sun’s ultraviolet radiation. During the eclipse, conditions will get even more Mars-like: the temperatures will go down even further, and the Moon will buffer some of those ultraviolet rays to better resemble the radiation on the Red Planet. “It’s really quite an outstanding astrobiology and planetary protection experiment,” Green says.
A photo taken from the stratosphere (84,000 feet up) during one of Montana Space Grant Consortium's high-altitude balloon tests in 2014.
Photo: Montana State University
The bacteria that will fly to the edge of space is a particular strain called Paenibacillus xerothermodurans. It was first isolated from soil outside a spacecraft-assembly facility at the Kennedy Space Center in Florida in 1973, says Parag Vaishampayan, an astrobiologist at NASA’s Jet Propulsion Laboratory. These bacteria form shields of spores that allow them to survive even when conditions turn deadly. It takes around 140 hours at 257 degrees Fahrenheit to kill 90 percent of these bacteria, Vaishampayan tells The Verge.
“These are some of the most resilient types of bacteria that we know of,” says David J. Smith, a researcher in the Space Biosciences Division at NASA's Ames Research Center.
Last week, Smith finished mailing the bacteria — which are not dangerous for people or the environment — to the student groups. (Only 34 of the balloons will carry the bacteria.) The microorganisms are dried onto the surface of two metal cards the size of a dog tag. One card will fly to the stratosphere, while one will remain on the ground to function as a control group. On eclipse day, the balloons will launch every 15 minutes or so from states that are in the path of the Moon’s shadow, Des Jardins says. They’ll fly for about two hours, reaching the stratosphere and eventually popping because of the pressure drop. Once they’re back on the ground (a parachute will slow down descent), the students will track them by GPS, recover the metal tags, and mail them back to NASA.
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