SpaceX CEO Elon Musk is set to deliver a keynote address at the 67th annual International Astronautical Congress tomorrow, where he’ll outline his plan for interplanetary colonization beginning with Mars. As a bit of a teaser, Musk posted a couple of images from the inaugural firing of the Raptor interplanetary engine, which is designed for use with Space’s Mars Colonial Transporter craft.

SpaceX propulsion just achieved first firing of the Raptor interplanetary transport engine pic.twitter.com/vRleyJvBkx — Elon Musk (@elonmusk) September 26, 2016

Musk’s comments on the test note that the chamber pressure runs three times what’s present in the Merlin engine currently used to power Falcon 9, which means there’s a big force multiplier effect at play. He also added that the production targets for Raptor include specific impulse of 382 seconds, and thrust of around 3 meganewtons. Merlin has specific impulse of 282 seconds (311 seconds in the vacuum of space), and a relatively paltry 654 kilonewton (0.6 MN) at sea level, or 716 kN (0.7 MN) in a vacuum.

In addition to the original pic, Musk followed up with a second image from the Raptor test firing, which clearly shows “mach diamonds” visible within the fiery column of exhaust. Also called “shock diamonds,” these are visible patters resulting from shock waves created within atmosphere.

Tomorrow’s address, which takes places on day two of the IAC in Mexico at 2:30 PM ET (11:30 AM PT) should provide more info about Raptor’s progress, as well as about the particulars of Musk’s plan to get to Mars. We’ll be covering the event, letting you know how SpaceX intends to break us free of the surly bonds of Earth.