Thank you both for your replies...
Wishbone: 1 AU is 149,597,870.7km or 149,597,870,700m x 1283772 AU
=
192,049,557,664,280,400m which is the distance from here to Gliese in meters.
Can IEEE floating point numbers comprehend this?
If not, would the entire orbiter core have to be re-written...