The SpaceX Dragon spacecraft made a successful touchdown, returning nearly two tons of equipment to Earth from the International Space Station (ISS).
Dragon touched down on 18 May, after completing its third re-supply mission to the space station.
Among the payload coming back from the station were several experiments, conducted while in orbit.
"While some of this data can be obtained by on orbit analysis, many analysis techniques have not been miniaturized or modified to allow them to be performed on orbit, which means sample return is the only way to obtain this data," Marybeth Edeen, of the Johnson Space Center, said.
One of these experiments was MicroRNA Expression Profiles in Cultured Human Fibroblasts in Space (Micro-7). This experiment studied the effects of space on DNA, and how genetic material repairs itself from damage in a spacecraft. As humans begin to colonize the moon and Mars, medical personnel will need to know how long-term exposure to spaceflight can affect living cells.
The Antibiotic Effectiveness in Space (AES-1) package is another medical experiment conducted by the ISS, which came back with the Dragon spacecraft. The AES-1 examined antibiotic resistance in space on colonies of e-coli bacteria. Medical personnel working on the experiment believe antibiotics may be less effective on bacteria in space than on Earth.
University of Florida researchers developed the BRIC-1 experiment, which attempted to grow two varieties of anti-biotic resistant bacteria. These were common bacteria found in soil called Bacillus subtilis, and an organism that lives on human skin, Staphylococcus epidermidis. When the cells are returned to researchers, they will be closely examined for signs of mutations, possibly caused by exposure to conditions in space.
Two experiments returning aboard Dragon examined more complex life forms, and the effects of space travel on their biological processes.
Saccharomyces cerevisiae, a brewer's yeast, was studied in the Advanced Plant Experiments-02-2 (APEX-02-2) package. The cells were exposed to radiation, in order to determine how the organisms change and adapt to the harsh conditions.
Seedlings were the test subjects in the BRIC-18-2 experiment, developed by researchers from Michigan State University.
"In [space] environments plants can undergo stress induced by a number of factors including changes in gravity, radiations, vibration, limited exchange of gases and suboptimal growth conditions. To facilitate plant life in space, it is crucial to acquire a better understanding of the genetic changes in plants that enable adaptation to the spaceflight environment," NASA officials wrote on the experiments home page.
