In this May 29, 2014, file photo, Elon Musk unveils the SpaceX Dragon V2 spaceship at the SpaceX headquarters in Hawthorne, Calif. (Jae C. Hong/Associated Press)

Elon Musk and his company SpaceX aim to colonize Mars with humans [“SpaceX’s ‘mind-blowing’ Mars plan,” Economy & Business, June 11]. Does this entrepreneur from Silicon Valley realize that if he is not careful, he will probably also colonize Mars with terrestrial microbes? Finding native life on Mars could contribute significantly to our understanding of life on Earth. If we inoculate Mars with Earth microbes, how will we be confident that anything we find is Martian?

As pleased as I am that people could be walking on Mars by 2025, I wonder what the rush is. Humans have much work to do before they can sustain themselves outside our planet. Spending an extra decade or two learning about interplanetary biocontainment would not prevent development of an “Earth-Mars Express.” Patient, science-driven initiatives would produce meaningful planetary protections; such efforts may even improve infectious disease control among non-astronauts.

Josh Stern, Silver Spring