[Featured image: Gale Crater on the surface of Mars, courtesy NASA]
Here’s another sneak peak from The Maven’s 4th edition of Microbiology, A Systems Approach. Since this piece was written, a debate has arisen over the need for protection of Mars – see below.
The Curiosity Rover has captured the attention of scientists, astronomers, and amateur stargazers alike with its fascinating pictures and analysis of the surface of Mars. One of its missions is to determine if there is water on the surface of the Red Planet, but after a recent controversy has come to light, NASA officials are hoping that it won’t find water after all. To protect the rover from any contamination, technicians worked in clean room conditions and routinely wiped all surfaces with alcohol, and sterilized equipment whenever possible. Six months before the launch of Curiosity, engineers became concerned about an important drill mechanism designed to dig into the surface of the planet in search for water. They decided to open the sterilized box holding the drill bit and mount it on Curiosity in case of any problems during the landing. When they did so, they exposed the drill bit to microbes from earth that could make their way to Mars. According to NASA’s Planetary Protection Guidelines, the rover was required to carry no more than 300,000 bacterial spores on any surface that might make contact with the Martian landscape. However, bacterial endospores not only are impervious to the disinfecting action of alcohol and are known to survive the vacuum and radiation of space, and if Curiosity finds liquid water, any endospores contaminating the surface of the rover could germinate and reproduce. It was estimated that approximately 250,000 endospores may have survived the space flight as a result of the breach in sterilization when the drill bit box was opened. Now NASA scientists are holding their breath to see if Curiosity discovers water – they don’t want the life they discover on Mars to be hitchhikers from Earth.
Since this piece was written for the text, a number of scientists have weighed in on the need to protect Mars from endospores from Earth. First, a paper entitled, “The Overprotection of Mars” was published in the journal Nature by Alberto G. Fairén from the Department of Astronomy at Cornell University and Dirk Schulze-Makuch of the School of the Environment at Washington State University. The paper asserts that transfer of microbes most likely has already happened through meteoric transport and that the sterilization requirements imposed by NASA are an unnecessary and onerous expense. A few months later, a rebuttal entitled, "Appropriate Protection of Mars," was written by Catharine A. Conley, the NASA Planetary Protection Officer and John D. Rummel, a professor of biology at East Carolina University and Chair of the COSPAR Panel on Planetary Protection. These authors assert that planetary protection efforts are continuously scrutinized and that the investment in sterilization of interplanetary probes is “not only worth it, but essential. The need for planetary protection is essential so that scientists who will one day visit Mars in search of life aren’t studying microbes that originated from their own planet. An article in Astrobiology Magazine outlines both sides of the debate.
[Planetary protection precaution measures utilized by NASA to protect Mars from bacteria from Earth. Image courtesy Universe Today]
What’s your take? Are planetary protection efforts worth the money and trouble? Do we need to worry about hitchhikers from Earth contaminating the surface of the Red Planet?Mars, new edition preview