Our strategy for Red Planet level 5-18 is to launch Ice Bird south, aiming for the two pigs on the first planet. Then launch Blue Bird on a north of the same planet and split just as it enters the VERY top of the gravity field pushing the lava asteroid down into the satellite. The score in the video below is 112,460.
We have compiled another video, demonstrating a strategy submitted by @dmsral and expanded upon by @f91jsw. The Ice bird is shot in the same was as the first video, but the Blue birds are fired into the planetoid above the fiery asteroid. It is not incredibly easy to replicate, but the Blue birds can knock the fiery asteroid downward, with the volcano pushing it into the heart of the structure. The score in the video below is 132,980, but it has the potential for a lot more.