You can add some RCS. The reaction whell (I don't know how to call it so...) of the probes are not powerful enough for something that size. If RCS is still not enough, put the grasshopper engine on the top and use it as (very big) RCS (PS: You may knew this before but people keep saying RCS is useless so plz click it before use, u have to turn it on)
You can add some RCS. The reaction whell (I don't know how to call it so...) of the probes are not powerful enough for something that size. If RCS is still not enough, put the grasshopper engine on the top and use it as (very big) RCS
Parachutes, solar arrays as grid fins. Making it bottom heavy and putting structural components at the top will make it bias to falling tail down as well