Recent news suggests that SpaceX are pivoting to hot-staging instead of the flip maneuver for getting Starship away from the booster. Looking at the Titan II hot staging it seems like it would be a violent and explosive event. How could this be mitigated? A hardened cover on top of the booster would be a significant weight penalty. Do the expected gains really outweigh the additional weight?
Extra mass on the first stage is far less burdensome than it is on the upper stage. That’s probably even more true here than in most rockets, given how early it stages. They might be able to get away with the mass of thermal shielding in the interstage. Steel is also fairly robust against heat, so perhaps it can withstand it for the few seconds which are required so long as they have somewhere else to hide the electronics and hydraulics
If you look at what happened with the interstage on the Titan II then you get an idea of some of the forces acting. Even after the second stage had moved away a few feet, when the engines throttled up the whole interstage was just blown apart. And that was just one small engine, not six raptors.
Perhaps the interstage will be sacrificial. Perhaps they don’t care at the moment because the early test boosters are not recoverable anyway. Maybe they’ll go back to the flip when other parts have been proven. So many unknowns.
I don’t know much about the Titan II but some of those early rockets couldn’t support their own weight and relied on internal pressure to maintain structural integrity. If they lost pressure they’d crumple. We already know the Superheavy booster is more robust than that so maybe with just some internal cooling it can survive hot staging.
Since Superheavy is still under power (center 3 engines, at 50%), maybe it just steers out of the exhaust before Starship lights the vacuum Raptors.
I feel like once they’ve proven SH can handle hot staging, they’ll eventually look into offsetting the vents on SH to redirect the exhaust preferentially in one direction to help give SH a kickstart in the flip maneuver. This in addition to SH always having a few engines lit would certainly help conserve fuel even if it’s just a tiny bit.
