For the first time, aerospace company Blue Origin has fired up a brand-new engine the company developed for its future moon lander. The engine, dubbed the BE-7, ignited for a full 35 seconds during a test at NASA’s Marshall Space Flight Center. The test marks a significant milestone for the company as it prepares to build its lander, named Blue Moon, and eventually send it to the lunar surface.

The news comes just over a month after Blue Origin founder Jeff Bezos revealed that the company had been developing the Blue Moon lander and the BE-7 engine for the last three years.

Bezos claims the lander is capable of carrying robotic rovers to the moon or even a separate spacecraft that can take off and transport astronauts away from the moon. He also noted that, because the BE-7 runs on liquid oxygen and hydrogen, it could potentially be fueled by water mined from the lunar surface.

Bezos tweeted out a video of the test in late June. The recording shows flames coming from the horizontally mounted engine, first appearing bright green and then turning clear for the rest of the test. The green flames can be attributed to the fluid that the BE-7 uses to start the ignition of the engine, likely some mixture of triethylaluminium and triethylborane. Once that fluid burns away, the flames become clear since the engine runs on liquid oxygen and hydrogen.

Bezos indicated that Blue Origin plans to use the Blue Moon lander to help with NASA’s plans to return humans to the surface of the moon. That opportunity may come very soon as NASA will send out a finalized call for lander designs this summer and will pick one or two companies to develop their versions of the spacecraft before the end of the year.