When you take on some of the kill ship missions, the tragets are carrying some items that can go for a hefty price on the market. Recently, I took a mission to kill a guy and he was transporting alien artifacts. I tractored in a couple of boxes and destroyed the last one to complete the mission. Later, I was able to sell the mission cargo for about $3000 a piece, ofr a total of $18,000. It wouldn't work at the first base, but after i went to another base it was easy money. I imagine that some of the deadlier viruses and the like should rake in the dough!

The ability to destroy a planet...is just plain fun.