SpaceX has had an incredibly busy year thus far, with a steady series of rocket launches and new initiatives like Starlink in the very earliest stages, and all the while the Starship project looming over it all. Starship is SpaceX’s future-looking rocket platform that could one day ferry travelers to Mars and beyond, and in a series of tweets over the weekend, CEO Elon Musk offered a few hints as to how things are progressing.

As TechCrunch reports, Musk fired off the messages on Sunday night, providing some details about the status of a recent engine test and a short-term forecast.

SpaceX has put Starship’s engines through a number of tests already, but that’s just the first of many steps between building a rocket and actually launching it. The next big milestone will be the short-flight hover of the Starhopper, which is the scaled-down prototype built as a stepping stone to the full-sized Starship which is coming later.

According to Musk, the company plans to schedule its Starship presentation “a few weeks after Hopper hovers,” which Musk suggests will come in “late July.”

Starhopper’s first real flights will be a major milestone for SpaceX and the Starship program, but the company still has a lot of work to do before its spaceship of the future is ready for its own maiden voyage. At present, SpaceX is planning on having the spacecraft ready for commercial launches sometime in 2021 at the earliest, but any major setbacks could push that timeline back.

One such delay came back in January when the Starhopper actually tipped over due to high winds at the launch facility. The spacecraft sustained light damage and things had to be put on hold for a few weeks while the company repaired the damage.