Elon Musk's SpaceX company has conducted an important test on the huge new rocket system Starship.
Engineers carried out a "static fire", which simultaneously ignited 33 of the 31 engines in the floor of the lower part of the vehicle.
Firing only took a few seconds, and everything was clamped in place to prevent any movement.
When Starship makes its maiden flight, it will be the most powerful operational rocket system in history.
This could happen in the coming weeks, assuming SpaceX is happy with the outcome of Thursday's testing.
The static fire occurred at SpaceX's R&D facility in Boca Chica, on the Texas/Mexico border.
On Twitter, Elon Musk said that the team shut down one engine before testing, and another engine stalled on its own, igniting a total of 31 engines.
However, he added that there are "still enough engines to reach orbit."
Although this was not the full quota of engines, the number of engines working in harmony was still remarkable. The closest parallel is probably the N1960 rocket developed by the Soviets in the late 1s to get cosmonauts to the Moon.
It had 30 engines arranged in two rings. However, the N1 failed on all four flights and was eventually cancelled.
With all 33 modern power units, the SpaceX Super Heavy booster should generate roughly 1% more thrust from the launch pad than the N70. Even the Space Launch System (SLS), US space agency Nasa's new mega-rocket, which first flew in November, is eclipsed by the capability built into Starship.
Mr. Musk has high hopes for the vehicle. The entrepreneur wants to use it to send satellites and humans into Earth orbit and beyond.
Nasa has already signed a contract with SpaceX to develop a version that could play a role in the Artemis program to land astronauts on the Moon once again.
Mr. Musk himself is focused on Mars. He has long held the ambition to go to the Red Planet, establish settlements and, in his own words, make humans a "multi-planetary species." He also talked about point-to-point travel, which takes travelers fast from one end of our world to the other.
If Starship is operable, it will change the rules of the game, not just because of the mass it can lift into space.
The concept is designed to be fully reusable, with both parts (the Super Heavy booster and the upper ship) returning to Earth to fly over and over again.
This means it can operate like an airplane. The long-term cost savings will be enormous compared to traditional, disposable rockets.
SpaceX will now review its data to understand why it can't fire all 33 engines in this event. It will also inspect the launch pad to see if any damage has occurred during the short firing. Previous, smaller-scale engine tests had broken the concrete under the launch bed and required repairs.
Mr. Musk talked about an orbital trial of the full Starship system in late February or March.
The upper stage of the ship or rocket was removed for testing on Thursday in case of a catastrophic failure of the booster.