Just before his scheduled presentation about colonizing Mars, SpaceX CEO Elon Musk shared a rendering on Instagram of his monster interplanetary rocket sitting on the surface of the Moon. Captioned simply with “Moon Base Alpha,” the photo hints that Musk will discuss how his vehicle, known as the Interplanetary Transport System, could be used to establish a human presence on the lunar surface.

Moon Base Alpha A post shared by Elon Musk (@elonmusk) on Sep 28, 2017 at 7:44pm PDT

Not much more is known about these Moon base plans, but the idea alone is a big change for Musk’s vision. The SpaceX CEO has long been a staunch supporter of colonizing Mars and not the Moon. In a paper about his colonization plans, he wrote: “We could conceivably go to our Moon, and I actually have nothing against going to the Moon, but I think it is challenging to become multi-planetary on the Moon because it is much smaller than a planet.” Conceivably, Musk has changed his mind on that now.

That may have to do with pressure from the Trump administration and the space community at large. Vice President Mike Pence has hinted that the new administration may call for a return to the Moon. And numerous space agencies — including Russia, China, and the European Space Agency — are interested in missions to the Moon, as well as a number of companies from the private sector. By showcasing how his rocket could be used for a Moon mission, he may have an easier time selling the idea to potential customers.

Mars City Opposite of Earth. Dawn and dusk sky are blue on Mars and day sky is red. A post shared by Elon Musk (@elonmusk) on Sep 28, 2017 at 8:03pm PDT

Musk isn’t completely off the Mars train, though. After revealing a Moon base rendering, he also shared a picture of what SpaceX’s future Martian city could look like, too. Perhaps he’ll also talk about the Moon being used as a stepping stone to get to Mars, as many others have argued for.

Hopefully we’ll learn more about these plans at his talk at the International Aeronautical Congress in Adelaide, Australia, which is slated to start at 12:30AM ET on September 29th. You can watch it online here.