A year ago, there was little evidence beyond a few tweets, engine tests, and slideshows to indicate that SpaceX was building a massive spaceship capable of traveling to other planets.

But the past 12 months have shredded all doubt about whether Elon Musk's rocket company is planning to aggressively go after its goal.

Development of Starship is underway, and one prototype has already completed a few short hop tests, which bring the vehicle a short distance into the air before softly landing it back on the ground. SpaceX is now ready to move to a more powerful test vehicle that could be capable of flying into Earth's orbit.

CEO Elon Musk teased a few images this week of the new prototype under construction at a SpaceX testing site in Boca Chica, Texas. The peek comes ahead of an event that Musk will host at that location on September 28. He's expected to give the most detailed presentation in two years about SpaceX's plans for interplanetary travel.

The first prototype SpaceX built was nicknamed "Starhopper." It was used to conduct the hop flights over the past few months. Those tests in Boca Chica were designed to check the spacecraft's ability to make controlled landings, an important task if Starship will one day land on Mars, like Musk hopes.

Starhopper passed a key final test last month, when it executed a precise landing after soaring about 150 meters in the air.

The new prototype is expected to be a significant upgrade, adding two or more rocket engines. Musk said in a tweet last month that SpaceX will conduct one hop test with the new vehicle in October. Then, the company will attempt to send the craft into Earth's orbit.

The latter feat will be by far the most intense test yet for the technology. Escaping the grip of Earth's gravity requires a rocket to reach "escape velocity" — which means topping 25,000 miles per hour, or 33 times the speed of sound.

Musk's ultimate goal is to establish a human settlement on Mars. To accomplish that, Musk has said Starship would need to fly into Earth's orbit atop a gargantuan rocket booster, which Musk dubbed Super Heavy. Starship would break off from Super Heavy after reaching space, allowing the spaceship to use its entire tank of fuel to make the six-month trek to the Red Planet.

SpaceX fans will be listening closely to Musk's talk in Boca Chica next week for updates on how the specifics of Starship and Super Heavy's design may have changed since Musk gave his last in-depth talk about colonizing Mars in September 2017.

Since then, Musk has relied on Twitter to give sporadic updates about the rocket's development. Notably, in late 2018, Musk announced the names Starship and Super Heavy would replace the previous nomenclature of "BFR" — "Big F---ing Rocket," or, in family-friendly terms, "Big Falcon Rocket."