The idea on solar sails is that they don't need to send something in the opposit...

		sageikosa on March 5, 2013 \| parent \| context \| favorite \| on: Dennis Tito's mission to Mars The idea on solar sails is that they don't need to send something in the opposite direction, they steal momentum (vectored in the travel direction) from the gases and/or photon radiation emitted from the Sun.