Controversy Grows Over whether Mars Samples Endanger Earth

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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
By 
Leonard David
 on June 23, 2022 
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? 
So-far-elusive answers to these questions could profoundly shape not 
only MSR but also the hoped-for follow-on of sending humans to 
Mars’s surface. Can astronauts live and work there without 

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inadvertently introducing earthly microbes to the Red Planet? And 
perhaps more importantly, can they eventually return home with the 
certainty that they carry no microscopic Martian hitchhikers? The 
protocols hammered out for MSR will be a crucial component in 
resolving those eventual quandaries.