I noticed that with my particularly rocket, having the particle systems as children to the rocket would cause the success/fail particle systems to rotate with the player which ended up looking quite weird at times.
If anyone else is wondering, a quick way to fix this is to prefab the particle systems themselves, remove them from the player prefab, and drag the prefabbed particles back into the serialized fields in the inspector.
Lastly, in your code, insert this line:
Instantiate(successParticles, transform.position, Quaternion.identity);
successParticles.Play();
This will create a instance of the particle system when the player collides and will not move/rotate with the player.