A new study published in the journal Science on Thursday, May 30, provides the most realistic assessment to date of the radiation dose an astronaut would receive on his or her flight to and from Mars, meaning we are inching closer to determining whether a manned Mars mission is even feasible.

The data is not a greenlight for sending humans to Mars. But scientists can use these measurements to develop better systems that protect astronauts from radiation during their deep-space expedition, and once they plant their boots on Mars. That includes measures like deploying solar storm shelters ahead of time, Chris Moore, deputy director of advanced exploration systems for NASA, said in a news conference on Thursday.