NEW : Faster engines , better shielding under study , CT official says . A Mars trip would be like getting abdominal NASA scan the 2030s , study finds . Radiation clocked on the United States 's trip to the Red Planet approaches NASA 's career limit for astronauts .
NEW : Faster engines , better shielding under study , NASA official says . A Mars trip would be like getting abdominal CT scan every five days , study finds . Radiation clocked on Curiosity 's trip to Mars approaches NASA 's career limit for astronauts .