My son has since confirmed that he had the following:
6956 - Stellar Recon Voyager
6886 - Galactic Peace Keeper
6841 - Mineral Detector
6822 Space Digger
6876 - Alienator
We are still unable to identify the large thin, odd shaped 'wings' sticking out from either side or what parts were used to make what looks like either stabilizers or possibly docking ports.
I have managed to download all the assembly instructions for the models mentioned above.
Unrelated to the space series he also had several basic brick sets, the 8862 Backhoe Grader and a helicopter that we have not positively identified yet. Do not think any parts in the picture came from them.
Thank you for responding to my query.