[lamontcg]

No, that's not how gravity boosts work. If you match speeds with an object you actually get zero boost.

The point of a gravity boost is to come in pretty hot (relative to the body you're boosting off of) and then go out pretty hot in a different direction. So you take your relative velocity vector at the point of the encounter and twist it around. By doing that you change your orbital energy around your central body (the sun) by a lot, and the other object will lose a similar amount to keep the bookkeeping equal.

If you have zero relative velocity compared to the thing you want a gravity assist off of you can't get an assist. It isn't like drafting a semi.

[stnmtn]

Interesting, do you mind explaining how the "other object will lose a similar amount"? I find orbital mechaics fascinating and understand the concept of a slingshot, but I can intuitively understand how if we launched a rocket and slingshotted it around the moon, the moon would be affected by that

[geenew]

Could there be some energy advantage to being in orbit around it? I'm thinking of a scenario where you spend a large amount of energy once get into orbit around the object, but then gain a small amount of energy continuously through something like tidal forces.

[lamontcg]

Everything else is going to be small and average out over time. And if you manage to pick up a bit of energy orbiting a tiny object you'll quickly just get ejected at its (small) escape velocity. Whatever that gives you, it won't be worth the cost of matching orbits to start with. Better to come in hot and slingshot.

Solar wind / radiation pressure is probably the next best free ride since that adds up over time continuously and is everywhere.