Stringer is the captain of the USS Neil A. Armstrong I.
The Long Mars
Back in the 2040's in Happy Landings, a group of Next now known as the 'Napoleons' offered their leadership to the community's elders but got rejected. They attempted a coup d'état but their reign didn't last long thanks to the USS Neil A. Armstrong I. The elders then requested Captain Stringer to bring the 'Napoleons' aboard as prisoners to exile them in a remote Long Earth from where they wouldn't be able to come back from.
Aboard the ship, they manage to seduce most of the crew to the point where a fight occured between them and the rest led by Stringer. They eventually won and took control of the ship and dumped everyone else oustide the ship (even their followers) except Sam Allen who was hidden in the Armstrong's envelope at the moment.
It was Sam who provoked the crash of the ship on Earth West 182,674,101 where he lived for several years as a prisonner to the Next until he was found by Snowy, who was part of the crew of the USS Neil A. Armstrong II in May 2045.
After having discovered Sam and questionned David, the leader of the 'Napoleons', the twain crews finally had some understanding of what happened to the Armstrong I.
- ↑ The Long Mars - Chapter 32