Starship is the space system that will take humans to Mars. A first launch of both the Starship spacecraft (with the same name as the entire system) and the Super Heavy launch vehicle into orbit has been talked about for over a year, without yet having happened.

During Tuesday, however, Spacex carried out an important test in order for such a launch to take place. The countdown to just before launch was carried out and in addition the rocket was refueled with around 450,000 tons of fuel. In English this is called “wet dress rehearsal”. According to Philip Påhlsson at the Swedish Space Corporation, there is no good Swedish translation, but an alternative could be “cold countdown with test of refueling and fluids”. The Starship spacecraft has six Raptor engines and Super Heavy 33, which are powered by liquid oxygen and liquid methane.

– A wet dress rehearsal is something you do as a last step before postponement to see that you don’t have leaks or the like. In some cases, a clamp-down test is also added when the engines are switched on for a number of seconds to see that the propulsion systems are working as they should, says Philip Påhlsson.

But more tests remain before it’s time for launch, including a static firing test of the Super Heavy’s 33 engines. So far, 14 have been fired simultaneously, which happened in November, reports Ars Technica.

Starship is not going up into a “real” orbit, but a transatmospheric orbit which means it would quickly fall back down if left there. The boundary between a transatmospheric orbit and a “real” low Earth orbit (English: Low Earth Orbit) is usually said to be at 80 km. The idea is that the craft will spin one lap around the earth and then fall into the sea around Hawaii. The launch will take place from Spacex’s Starbase in Texas.

No date has yet been nailed down. According to Space Flight Now, it could be the end of February.

With spacecraft and launch vehicle assembled together, the crew measures 120 meters in height, and must be able to bring 100 tons to low orbit.