Elon Musk said on June 24 that SpaceX has changed its approach to separating the two stages of the Starship spacecraft to improve payload performance ahead of the next test flight. INSIDE online discussions Speaking to Bloomberg reporter Ashley Vance on Twitter, Musk’s social network said SpaceX has recently decided to switch to a “hot launch” approach, where Starship’s upper stage will fire the engines while the superheavy is still attached to the rocket. amplifier.

“We made one final change that was really very important to how phasing works,” Musk said, announcing the move to hot staging. “In a hot-stage orbit, there is a significant payload advantage, which is discreetly about 10%.”

The hot stage, which has been used in Russian launch vehicles for decades, involves firing the engines in a single stage still attached to the lower stage. Musk said most of the 33 Raptor engines in the Super Heavy launch vehicle for Starship will be shut down, but some will continue to operate once the engines in the Starship’s upper tier are fired. According to him, this prevents loss of traction in the case of a conventional staircase split when the bottom rung is closed first.

This will require some modifications to the super heavy booster. Musk said SpaceX is trying to widen the top of the launch vehicle “which has pretty much all of the vents” to allow the top stage exhaust to escape while remaining attached to the launch vehicle. SpaceX will also add shields to protect the launch vehicle from exhaust fumes.

“I think that’s the riskiest thing for the next flight,” he said of the new ladder splitting technique.

In addition to changing the phase separation, Musk said SpaceX has made “over a thousand” “many” other changes to the vehicle. He didn’t go into details about the changes, but noted that the company continues to upgrade the launch pad to prevent damage such as the “steel sandwich” overflow system caused by the Starship’s initial launch on April 20. “We’re actually going to go overboard with the steel sandwich and concrete, so we have to get a much better shape for the cushion base than we did last time.”

SpaceX also developed the Raptor’s engines, and Musk described the ship’s April launch as a “mix” of engines built over time. Raptors on new cars include changes to the hot gas manifold in the engine to reduce fuel leakage.

He said these changes gave him more confidence in the success of the next launch. “I think the probability of the next flight to work, to enter orbit is much higher than the previous one. Maybe around 60 percent.” In an online chat in late April, he predicted “more than 50% chance of success” at the next launch.

Musk did not specify a specific launch date. “There are many variables that are out of our control,” he said, clearly referring to the Federal Aviation Administration’s launch licensing process. “We expect upgrades to the launch pad, launch vehicle and ship will be ready in about six weeks.” Musk said in a phone call in April that he expects to be ready to fly “in a few months.”

Earlier in the conversation, Musk declined to comment on recent rumors that SpaceX is considering expanding its Starlink satellite broadband business and holding an IPO. Fox Business reported on June 21 that SpaceX investors are reviewing Starlink’s subsidiary and IPO this year so that Musk can raise money for other startups like Twitter.

Asked about Starlink’s IPO plans, Musk declined to comment. “It would be illegal for me to speculate on the Starlink IPO,” he said. “I think it’s against the rules to discuss any details about a future IPO.”

Musk had previously downplayed any talk of deactivating and going public with Starlink. He said he was “thinking of that zero” in 2020 to focus on making the broadband service technically and financially successful. At the company’s internal meeting in June 2022, Musk said he didn’t know when SpaceX would make Starlink public, but he predicted it would be at least three to four years from now. Source