Controversy Grows Over whether Mars Samples Endanger Earth

Planetary scientists are eager to bring Red Planet rocks, soil and even air to Earth, but critics fear the risk of contaminating our world’s biosphere 

Less than a decade from now, a spacecraft from Mars may swing by Earth to drop off precious cargo: samples of the Red Planet’s rocks, soil and even air to be scoured for signs of alien life by a small army of researchers right here on our terra firma. Orchestrated by NASA and the European Space Agency, this fast-paced, multibillion-dollar enterprise, formally known as the Mars Sample Return (MSR) campaign, is the closest thing to a holy grail that planetary scientists have ever pursued.

In many respects, MSR is already well underway: NASA’s Perseverance rover is wheeling around an ancient river delta in Mars’s Jezero Crater, gathering choice specimens of potential astrobiological interest for future pick-up by a “fetch rover.” Then there’s the design and testing of the Mars Ascent Vehicle for lifting those retrieved samples into orbit for subsequent ferrying to Earth that is proceeding apace. But one crucial aspect of the project remains troublingly unresolved: How exactly should the returned samples be handled and at what cost, given the potential risk of somehow contaminating Earth’s biosphere with imported Martian bugs?