SpaceX will debut numerous upgrades on the second launch of its full-scale Starship mega-rocket. Those upgrades include a major change in how the rocket’s two stages separate, propulsion system improvements, and a beefed-up launch pad in South Texas that should better withstand the blast from 33 main engines.

“There are really a tremendous number of changes between the last Starship flight and this one, well over a thousand,” said Elon Musk, SpaceX’s founder and CEO. “So I think the probability of this next flight working, getting to orbit, is much higher than the last one. Maybe it’s like 60 percent. It depends on how well we do at stage separation.”

Musk outlined some of the Starship rocket modifications in a Twitter Spaces discussion on Saturday with journalist Ashlee Vance. He said the next Starship rocket and upgrades to the launch pad at the Starbase facility in South Texas should be ready for the next test flight in about six weeks. “That’s just the best of our knowledge right now,” Musk said.