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Amir Alexander

Phobos LIFE Experiment Designs Finalized, Hardware in Production, Important Partnerships Established

Posted by Amir Alexander

31-07-2008 12:00 CDT

Topics: Planetary Society, Planetary Society Projects, Phobos and Shuttle LIFE

Our preparations for sending out microbes on a roundtrip to the Martian moon Phobos and back have shifted into high gear. We have now completed the design of the ultra-tough canister that will be the organisms' "home" during their three year trip on board the Russian Phobos-Grunt spacecraft. An engineering model of the disk-shaped canister is currently in the works, and a flight module will follow within months.

On the scientific front we have recruited superb new collaborators in both the United States and in Germany, and we are now close to finalizing the list of microorganisms the will make the journey to Phobos and back. With all this activity, there is a newfound excitement and intensity for the project's team: The LIFE experiment is preparing for launch.

Important Collaborations Established with ATCC and DLR

In a major development for our project, the American Type Culture Collection, known as the ATCC, has agreed to contribute its resources and expertise to the experiment. The non-profit ATCC is the organization charged with storing and characterizing microorganisms for scientific uses in the U.S., and it is the place where researchers go to obtain microorganisms for study. The ATCC scientists are the experts at handling microbial samples and doing things like drying them for storage. Having ATCC on board is a terrific boon to the LIFE experiment. {NOEDIT_sidebar} The ATCC will provide many of the microorganisms for the experiment, and characterize them before and after the flight to determine how they were affected by exposure to deep space conditions. But that is not all: led by Marian McKee, Director of Microbiology Collections, the ATCC team is currently working with George Fox and David Warmflash to test different methods of loading the bacteria into the sample tubes. The leading option at the moment is to dry the samples on thin laboratory paper, cut the paper into small disks and then stack them inside the tubes, but nothing has been finalized as yet. Once the best method has been established and tested, the ATCC team will be responsible for loading the bacteria into the tubes.

As befits an experiment investigating the origins of life on our planet, our project is also becoming increasingly international. In addition to the American and Russian participants, we are now also beginning collaborations with a very experienced team of scientists in Germany. Researchers from the German space agency, known as the DLR, have been flying bacteria on space missions for decades, and currently have several active experiments going on the International Space Station. The group leader, Petra Rettberg, has agreed to provide our experiment with two strains of bacteria that have previously flown in space. This could prove extremely valuable for the project, because while the "German" bacteria have spent time in space, they remained in low Earth orbit and were protected from radiation by Earth's magnetic field. Comparing them with the identical strains that have spent years in interplanetary space is crucial to interpreting the results of the LIFE experiment.

With input from the ATCC researchers and the German team, the list of organisms that will be included in the experiment is now being finalized. All three domains of life will have representatives in the LIFE experiment: Bacteria, Archaea (both of which exist only as microorganisms), and Eukaryotes (which also include all forms of complex life). This will make it possible for scientists to compare how the different domains of life deal with the harsh conditions of space. Will one domain survive the trip better than others? Whatever the case turns out to be, it will have profound implications for the transpermia hypothesis.

Clever Design Finalized

Meanwhile, as the scientific details of the experiment are coming into focus, we are also making rapid progress in designing and manufacturing the experiment's hardware. From the beginning we knew that engineering a container to house the LIFE experiment was one of the main challenges of our project. We needed to design and build a canister tough enough for the harsh conditions of space and the return to Earth, hardy enough to survive any mishap, and light enough to be included in the mission's payload (less than 100 grams). After considering several possible options, we ultimately settled on a model that combines light weight (always a consideration on space missions), ease of handling, and a near-indestructible outer shell. The final version of the canister is the brainchild of Bud Fraze, who designed and built it with continuous input from Tomas Svitek, his colleague at Stellar Exploration, Bruce Betts of The Planetary Society, and the LIFE science team.

At the very heart of the canister, the microbial samples will be housed in thirty tiny sample tubes made of polyoxymethylene plastic, more commonly known as "Delrin." The sample tubes will in turn be snugly encased in an "inner carrier," also known as the "biomodule container," which is also made of Delrin. An earlier plan to construct the carrier from ceramic was scrubbed when it became clear that Delrin is cheaper, easier to handle, and possesses comparable space characteristics.

In the middle of the inner carrier, surrounded by the 30 sample tubes, is a single cavity many times larger than the sample tubes. Inside this area will be placed the "colony container," which houses not one single organism, but a soil sample containing many different types of microbes coexisting in a complex environment. Like the smaller tubes and their samples, the colony container will be hermetically sealed with a "colony cover," and the entire biomodule container is then topped with a fitting "carrier cover." The container and its cover are sealed with a silicone O-ring that fits between them, and are held together by specially designed "retaining clips."

During the long journey through deep space, the biomodule container will be the heart of the LIFE experiment. It will carry the microorganisms and serve as a test of the transpermia hypothesis. which posits that microorganisms may have migrated from planet to planet sheltered inside meteoroids. But in order to approximate the conditions inside rocks traveling through interplanetary space, as well as protect against the possibility that the LIFE samples will contaminate the environment of Phobos or Mars, the inner container must be encased in several additional protective layers.

First is a circular retaining seal made of Kapton, which is fitted tightly around the edges of the inner container, helping to keep it sealed and fitting snugly in the external shell. Next come shock pads made of poron, one above and one below the inner container. And finally the two parts of the titanium external shell, both light and exceedingly strong, one above and one below the inner container. They will fit together snugly with an indium O-ring in between, hermetically sealing the inner container and its precious cargo.

To help determine just how harsh conditions on the trip become, several radiationdosimeter chips and a several small temperature disks will be attached at various points inside the biomodule, recording the extremes of temperature and radiation.

This LIFE canister was designed and manufactured especially for the LIFE experiment by Bud Fraze and his colleagues at Stellar Explorations, Inc. We believe that this elegant, rugged and lightweight design may well have a future ahead of it quite apart from our experiment, and could be used by scientists both in space and on Earth. With this in mind we have applied for a patent on the design, which is now pending before the U.S. Patent Office.

With the new collaborations with ATCC and the German researchers, the list of organisms near completion, and the canister design finalized, the LIFE experiment will soon be ready to launch. This summer we will be delivering an engineering model to the spacecraft team in Russia, and the flight module itself, loaded with the samples, is due in Russia by December 31. Phobos-Grunt, with the LIFE experiment on board, is due to launch in October 2009.

 
See other posts from July 2008

 

Or read more blog entries about: Planetary Society, Planetary Society Projects, Phobos and Shuttle LIFE

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