SpaceX on Wednesday night shared a photograph and a video on its Instagram page of the 400th Merlin 1D engine produced by the company. It is the same engine that powers both the Falcon 9 and Falcon Heavy rockets used by Elon Musk’s space venture (but the Falcon Heavy hasn’t yet actually flown).

The company also said the engine (not the specific one they shared images of, but the Merlin 1D in general) has been fired for a total of over 6,000 times so far, of which about 440 were in orbital missions. That makes sense since each Falcon 9 rocket uses nine of the Merlin engines, and SpaceX is counting each individual engine when it counts the 400 firings.

That number will go up sharply once the company gets its Falcon Heavy rocket off the ground. The maiden flight has been delayed a few times already, and is currently scheduled for January 2018. But the Falcon Heavy essentially combines three Falcon 9 rockets, giving it a total of 27 Merlin engines. So even a single successful flight of Falcon Heavy will add significantly to the success rate of the engines.

Earlier on Wednesday, Musk had shared pictures of the Falcon Heavy rocket at the company’s facilities at the Kennedy Space Center in Cape Canaveral, Florida. These were the first pictures publicly shared of the rocket.

A few hours later, he shared another picture of Falcon Heavy to give an idea of scale.

Musk also said the rocket’s first mission, which is to deliver a payload to an orbit around Mars, would run at 92 percent thrust capacity. He added that all three rocket boosters of the Falcon Heavy will attempt to land back on Earth after sending the payload on its way.

It seems Musk is quite serious about that payload being his “midnight cherry Tesla Roadster playing Space Oddity” by David Bowie. In response to someone on Twitter asking him to confirm if his Roadster was actually aboard the rocket, Musk simply said: “Pics soon.”