protected void DoShow()
        {
            if (targetBody == null)
            {
                return;
            }

            switch (field)
            {
            case RadiationFieldType.INNER_BELT:
                KerbalismContracts.SetInnerBeltVisible(targetBody, set_visible);
                break;

            case RadiationFieldType.OUTER_BELT:
                KerbalismContracts.SetOuterBeltVisible(targetBody, set_visible);
                break;

            case RadiationFieldType.MAGNETOPAUSE:
                KerbalismContracts.SetMagnetopauseVisible(targetBody, set_visible);
                break;

            case RadiationFieldType.ANY:
                KerbalismContracts.SetInnerBeltVisible(targetBody, set_visible);
                KerbalismContracts.SetOuterBeltVisible(targetBody, set_visible);
                KerbalismContracts.SetMagnetopauseVisible(targetBody, set_visible);
                break;
            }
        }
 private void OnDestroy()
 {
     Instance = null;
 }
 //  constructor
 public KerbalismContracts()
 {
     // enable global access
     Instance = this;
 }