BFC

Starship Cargo or 'Big F***g Cargo' or 'Big Falcon Cargo' variants (BFC) on the BFR System

The BFC are two proposed version of upper stage of the BFR to carry cargo both into space for satellite deployment and a similar design for Cargo to Mars.

The BFC will like the BFS(Spaceship) will launch atop of the BFB(Booster) 1st stage and for going to Mars will be in-flight refuelled by the 4-5 additional BFT(Tanker variants) launches to enable it to fly a full payload to Mars.

The first four Mars mission will use the BFC, two planned for 2022 and two more in 2024 ready for two manned BFS in 2026.

Mars Cargo version

The BFC to Mars is going to be internally a lot different to the BFS for human and Cargo.

This version will need to be able to automatically unload cargo onto the Mars surface, requiring automated cargo doors and an intelligent crane to lower cargo from the main hold down to the ground, while items in the cargo bay will need to be automatically moved ready to be lowered by the crane.

One of the first item needed on the surface will be an automated rover(s) for checking around and mapping the landing site and nearby in detail to give feedback on initial deployment of the cargo.

Then an automated truck to transport the cargo maybe with some sort of crane onboard.

The Mars Cargo might include basic life support as it may be useful for the Mars colonist to work inside without a spacesuit and it could return humans to Earth if required, multiple life support options seems wise in any case.

From SpaceX website https://www.spacex.com/starship

"The Starship payload fairing is 9 m in diameter and ~19 m high, resulting in the largest usable payload volume of any current or in development launcher. This payload volume can be configured for both crew and cargo."

Satellite Cargo version

This version of the Cargo BFR will not need to be refuelled for LEO missions but may need to be for heavy GEO missions.

It has also been proposed it could also be used to collect space debris or defunct satellites.

Satellite BFC

Starship Satellite

A third possible variant could be for dispensing the proposed SpaceX Starlink Consolation of up to 11,943 communication satellites, but the FH most likely launch the first few thousand.