For most of its 14 year existence, SpaceX has focused on designing and developing the hardware that will lead to its ultimate goal: colonizing Mars. These plans have remained largely secret from the general public, as company founder Elon Musk has dropped only the barest of hints. But that is expected to change on Sept. 27, during a session at the International Astronautical Congress, when Musk details some of these plans for the first time in a public forum.

However, on the eve of the meeting, Musk dropped a surprise on Twitter. The workhorse spacecraft that will carry approximately 100 tons of cargo or 100 people to the surface of Mars, which until now has been popularly known as the Mars Colonial Transporter, can't be called that, Musk said. "Turns out MCT can go well beyond Mars, so will need a new name..." he tweeted on Friday evening. By Saturday evening he had a new name dubbing the spacecraft the "Interplanetary Transport System," or ITS.

Mars, it turns out, isn't the solar system's only marginally habitable world for would-be new world colonists. The Moon, Venus, the asteroid Ceres, and outer Solar System moons Titan and Callisto all have some advantages that could allow for colonies to subsist. However, Mars has generally been the preferred destination—due to its relative proximity to Earth, a thin atmosphere, and sources of water ice. Musk now seems to be suggesting that some of these more distant destinations, especially moons around Jupiter and Saturn, might be reachable with the Interplanetary Transport System.

Perhaps the most significant aspect of Musk's musings on Twitter is the signal that he does not intend to pull back from his grand vision of humanity becoming a multi-planetary species, even for a short time. Rather than pausing after the loss of a Falcon 9 rocket and its payload during the run-up to a static fire test on September 1, and focusing on mastering access to low-Earth orbit, Musk appears to be pushing full steam ahead into deep space.

It is not clear the extent to which Musk will detail his Interplanetary Transport System, or the booster that will launch it (the BFR—figure that acronym out for yourself), during the international meeting in Mexico next week. However, he is sure to have the considerable legion of SpaceX fans hanging on his every word while much of the rest of the aerospace community wonders how seriously to take the mercurial Musk. Yes, he has upended the global launch business with his sleek, low-cost rockets. But the company's credibility is also on the line after two losses of a Falcon 9 booster in just more than a year. Regardless, it will be a fascinating show, watched by all with even a remote interest in spaceflight.