Leshres speciality does not help him if he is going to fight an Astroviper any other type of viper (even fast blast and heat vipers) he could take but the Astroviper is in space leaving Leshresh with a big disadvantage.
However Leshresh would not be sent into space to fight because its better to use the money on sending star force personell with the training to take out Astro vipers. That is why I vot for Leshresh he would profile the Astroviper and take him out when he is down on earth on leave.