UI Number of halleys required

Is it possible to implement a counter in the UI that tells you how many halleys you have to build on moons before you can crash the moon into a planet

Unless I'm misunderstanding your question this already exists. When you zoom out to the celestial view there are some little icons below each celestial body indicating how many Halleys you need.

This already exists. If you zoom out to the celestial view, it'll show you how many halleys are required.

Video proof:


And for reference, here's how many halleys are required.

• 3 Halleys are needed to move a celestial body with a radius of 249 or less.
• 25 Halleys are needed to move a celestial body with a radius of 250 to 349
• Celestial bodies with a radius of 350 or greater cannot be moved by Hallyes