SpaceX changing Starship stage separation ahead of next launch

On April 20, the Starship from SpaceX completed its maiden integrated assessment flight. This achievement demonstrates the potential of this spacecraft for future space missions.

Elon Musk announced on June 24 that SpaceX is altering the way it detaches the two phases of the Starship vehicle in order to improve its payload capacity before the next trial launch.

During a Twitter conversation with Ashlee Vance, a reporter from Bloomberg, on the social media platform he owns, entrepreneur Elon Musk stated that his aerospace company SpaceX has opted to shift towards a method known as "hot-staging". This involves igniting the engines of the Starship upper stage while it remains connected to the Super Heavy booster.

Musk explained that they recently made a notable modification to the way stage separation operates which they made a decision on at a later time. They made the switch to hot staging and it has proven to be quite significant. Hot staging provides a considerable advantage when it comes to the payload that can be carried into orbit, with an estimated increase of 10% which is a conservative figure.

The procedure called hot-staging has been utilized by Russian spaceships for a long time. This method involves igniting the engines of one stage while it is still connected to the lower stage. Musk stated that for the Starship, several of the 33 Raptor engines on the Super Heavy booster would be inactive while the engines on the upper stage of the Starship were ignited. This is done to prevent any loss of power during the standard stage separation process, where the lower stage stops functioning before the upper stage.

To achieve this, changes need to be made to the Super Heavy booster. According to Musk, SpaceX is developing an expansion for the booster's top that is largely comprised of openings. This design will allow the fumes produced by the upper stage to exit while it remains attached to the booster. Additionally, SpaceX is planning to equip the top of the booster with a shield to prevent damage from the fumes.

He expressed his concern about the new method of separating stages, saying that he believed it was the most dangerous aspect of the upcoming flight.

In addition to altering the stage separation, Musk shared that SpaceX made a vast amount of other modifications to the vehicle – in excess of one thousand. Although he didn't specify the exact changes, he did mention that the business was still progressing with improving the launch pad to prevent any harm like the water damage from the initial Starship launch on April 20th. The technique implemented will consist of a powerful deluge system known as "steel sandwich" and reinforced concrete. Constructing these enhancements should provide more lasting protection to the foundation of the pad contrasting to the previous time.

SpaceX has improved the Raptor engines recently. Musk stated that the vehicle launching in April will incorporate a mix of engines created at different times. The new Raptors have undergone alterations to the hot gas manifold in the engine, resulting in lower fuel leakage.

He stated that the alterations made have bolstered his assurance that the next launch will be a triumph. He believes that there is a significantly elevated likelihood of the upcoming flight achieving orbit, compared to the previous attempt, possibly up to a 60% chance. During a virtual dialogue in April, he predicted that the chances of success on the next launch were more than 50%.

Musk did not mention a fixed date for the launch. He stated that there were many external factors that were beyond their control. This was a reference to the launch permit process conducted by the Federal Aviation Administration. Musk anticipates that the enhancements to the launch pad, booster and spacecraft will be done in approximately six weeks. During the conversation held in April, Musk mentioned that he will be prepared to launch within a few months.

During the previous part of the discussion, Musk did not give any information about the recent speculations that SpaceX was thinking about creating a separate company for its Starlink satellite broadband business and launching an IPO for it. According to a report by Fox Business on the 21st of June, investors in SpaceX predicted that Starlink would separate and conduct an IPO this year so that Musk could gather money for other projects, such as Twitter.

When asked about a potential Starlink IPO, Musk refused to discuss it, citing legal constraints. According to him, divulging specifics about a prospective public offering is prohibited by regulations, leaving him unable to make any predictions.

In the past, Musk has dismissed any rumors about separating Starlink from his other ventures and making it publicly available for investment. Last year, he indicated that he was more interested in dedicating his efforts to ensuring that the internet service was both profitable and advanced, rather than contemplating public offerings.

During a private gathering of executives in June of 2022, Musk stated that he was unsure of the timeline for making Starlink publicly available, but speculated that it could potentially be anywhere from three to four years away.

The author, Jeff Foust, produces written content on space-related issues like policies and commercial explorations for SpaceNews. He holds a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and an undergraduate degree with honors in geophysics and planetary science. Visit SpaceNews for more of Jeff's articles.