What are these "portholes & panels" on the fuselage of the Omega Tanker DC-10?

Question

If you take a look at the photo (source: still from this YouTube video), you'll notice a pair of "panels" on the fuselage of this Omega Tanker DC-10 (reg: N974VV), circled with green.

There is also a pair of "portholes" (circled red).

What are all those? Any relation to this being a tanker?

Note: Here's a photo that shows the "panels" closed on the ground.

Answer 1

The things circled in red are static ports. They are used to measure static air pressure. You can see a close up (from a different aircraft) here:

^{(taken from this answer)}

What you circled in green is an outflow valve used for controlling the pressurization. See also:

• What is this device below the door of a 737 (and other aircraft)?
• How does the outflow valve work on a cabin pressurization system?
• How does a DC-10 flight engineer manually raise the cabin altitude?

It is technically called a Thrust Recovery Outflow Valve:

The actual nomenclature is the "Thrust Recovery Outflow Valve"

[...]

The thrust recovery outflow valve is essentially the valve that controls cabin altitude throughout the isobaric selection range. It can be controlled electrically through 2 electric motors receiving input from the automatic and semi-automatic cabin pressure controller/computer. On the -10's with Flight Engineers, the clutches could be disengaged via a handle at the FE station, and the valve was then controlled through a manual wheel.

^{(Airliners.net)}

Both items are unrelated to the fact that this is a tanker. The following image shows the same items on a Northwest Airlines DC-10-40:

^{(Airliners.net)}