NASA has arrived at two ways of returning samples collected on Mars to Earth. Now, the agency will test the options to see if the cache can make it back in the 2030s.

The agency has collected 30 samples on the red planet but the cost of getting them back had delayed the Mars Sample Return mission. It was initially estimated at $11 billion, with a 2040 return date: a price tag and timeline that administrator Bill Nelson explained was “simply unacceptable.