NASA is planning its first ever mission to bring dirt and rocks from Mars back to Earth, but before that historical event happens, the space agency has to figure out (exact) how to protect our home planet from any alien microbes (微生物) that might come along.
This week, the agency is holding public meetings and looking for feedback on its plan (land) a spacecraft carrying Martian specimens at a U. S. Air Force testing range in Utah in the early 2030s.
"Maybe this is the most important environmental (assess) that humans have ever done," says Peter Doran, a geologist at Louisiana State University who studies life in extreme environments. Having a rock sample from Mars here on Earth would let researchers run detailed lab tests to look for evidence of this cold, harsh, rocky world was once habitable (可居住的) or maybe even inhabited.
For researchers, this is long-held dream. Discussion about such a mission (go) on for decades, and it will cost billions of dollars to accomplish. Until recently, there hasn't been a lot of focus on the details of the sample return facility because (science) didn't think it was going to happen.
NASA officials are working out a plan to safely collect the samples: A spacecraft would land on Mars and launch a container full of the previously (collect) rock samples into orbit around the planet. Once in orbit, this container could be swallowed by another container— a big fish eating a little fish—to keep anything that had touched Mars inside and then it would (seal).
