Really? Wish I'd known that. The amount of nhss I went though looking for those things! Gave up and poked around the crashed interceptor in the end. Going around scavenger locations seems like it would be more fun.They're also great for getting sensor fragments when you want to unlock Palin.
Now I find a sensor probe in about 1 in 5 nhss 4 signals. The rule of, if you're looking for it, you'll never find it definitely applies.