Mr Musk took posted images on Twitter of the “test hopper” prototype that is currently under construction in Texas.
He also responded to a flurry of questions from his followers about the spaceship and its rocket engine.
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Following speculation from one user that the space craft will make use of stainless steal, Mr Musk confirmed that it would use similar materials to the Atlas rockets first produced in the 1950s.
“Stainless steal is correct, but different mixture of alloys and new architecture,” Mr Musk said.
The billionaire entrepreneur shared the details following the successful launch of the Falcon 9 rocket, which lifted off from Texas on a separate mission to deliver a spy satellite into orbit.
He continued: “Actually, the only significant design element in common with early Atlas is stainless steel and we’re using a different alloy mix.”
The SpaceX boss also said the Raptor rocket engine that would help launch the spacecraft had been “radically redesigned”.
Mr Musk said more details about Starship would be revealed early next year following a test flight of the prototype.
“I will do a full technical presentation of Starship after the test vehicle we’re building in Texas flies, so hopefully March/April,” he tweeted.
Earlier this year, Mr Musk said SpaceX was aiming to launch the first manned missions to Mars in 2024.