If a space shuttle captain meets up with a captain in the navy or army, etc, who pulls rank??

lets assume the captain of the shuttle is actually a captain by rank not just of the mission/ship.

Assuming that they are all the same pay grade, say O-3, it would depend on whose turf they were on. If they on the space shuttle, he commands. On the Navy ship, it would be Navy guys final word. If they are on neutral territory, it would most likely be who ever has the best leadership skills. Which usually is connected to time in grade. The more time in grade, the more experience you have and the better you would be at leading. At the same time, any troops assigned to each O-3 would answer only to that one officer, no matter who is calling the shots.

It depends on what service branch the shuttle captain is in.The navy rank is higher than the army.

Captain of a vessel and the Rank of Captain are two different things.

The rank of Captain in the Navy is like a Colonel in the USAF/USA/USMC. The grade is an 0-6.

The rank of Captain in the USAF/USA/USMC is like a Navy Lieutenant. The grade is an 0-3.

While the same Title "Captain." The rank is different in the services.

Any rank can be the Captain of a vessel. Which is a title, not a rank.

If the person holds a rank in an armed service, it would depend on which armed service he was in. Captain is the same level (O-3) in the Army, Air Force, and Marines, but a higher rank in the Navy (O-6), so a Naval Captain ranks over any other Captain.