have you moved to right next to the shield in space? i personally have not had any problems with that mission.
just in case you missed it.. there is a ground complex on that planet. with a shield protecting it.
if you did see it and it still did not let you try and scan it while you are next to it.. the first thing a dev will tell you is to drop the mission and pick it back up and try again. then if it still doesnt work the second time threw.. make a bug ticket.