SpaceX’s Dragon capsule docked with the International Space Station for the fourth time on Sunday, delivering a number of important items. Included in the capsule’s cargo are a supply of coffee, which astronauts ran out of on Friday, a new laser communication system, a garden for growing fresh produce, and wide variety of bacteria.
The microbes didn’t hitch a ride by accident this time, however. In fact they were meticulously collected from a variety of surfaces. Bacteria was collected from all over the country, including some from a fossilized Tyrannosaurus Rex named Sue, a basketball used in an Orlando Magic game, a Mars rover, and the Liberty Bell.
The experiment, entitled Project MERCCURI, will consist of two parts. First, the microbes from Earth will be examined on the ISS. Astronauts will monitor how the bacteria grow and multiply in microgravity and compare it with how the same microbes grow on Earth. Second, the Dragon capsule will bring back microbial samples taken from the ISS. Scientists will examine the kinds of bacteria that have survived and thrived aboard the relatively clean environment of the space station and use DNA sequencing to take a closer look at the structure of the microorganisms.
Previous research has shown that many microbes grow faster and stronger in space than they do on Earth. NASA has sent a number of disease-causing bacteria to the space station to examine potential health risks for future astronauts. For reasons that are still unclear, astronauts’ immune systems become weaker in space, making them more vulnerable to disease.
A sample of Salmonella sent in 2007 became more virulent after its time in microgravity. Mice injected with the bacteria on earth succumbed to disease far more quickly than those infected by normal, Earth-born Salmonella. Other microbes clustered together in thick groups of cells known as biofilms. Some even formed biofilms in structures never seen among Earth bacteria.
Around 90% of the cells in the human body are microorganisms, so keeping bacteria out of space is impossible. Through research projects like MERCCURI, scientists hope to better understand how microbes grow and change in the unique environment of the ISS. New discoveries could help protect astronauts from disease, making the harsh conditions of space a little bit safer.