Letters to the Editor Planetary Science Readers weigh in on human gene editing and more Your letters and comments on the January 20, 2018 issue of Science News By Science News Staff February 22, 2018 at 11:39 am - More than 2 years ago Share this:Share Share via email (Opens in new window) Email Click to share on Facebook (Opens in new window) Facebook Click to share on Reddit (Opens in new window) Reddit Click to share on X (Opens in new window) X Click to print (Opens in new window) Print Mission: Mars The possibility that human visitors could carry Earth-based microbes to the Red Planet has roiled the Mars research community, Lisa Grossman reported in “How to keep humans from ruining the search for life on Mars” (SN: 1/20/18, p.