Commander Cook is the highest ranking navigator on the Sleipnir. He is the commander of the 7th Federation Alliance Fleet. Due to his involvement in The Shady Plan, he has given Abel the assignment to reconfigure the engine of the starfighter Reliant.
The commanders have their own suites on the Sleipnir.
He is most likely named after James Cook, an 18th century British explorer.
He has sexual relationships with young navigators as we see when Phobos goes to visit Cook, only to see a young navigator leaving which is when Phobos says to Cook "they just keep getting younger, don't they?"