2 comments

• Max

  March 2, 2024 at 1:05 pm

  Just watched this deep dive into the engineering and construction of the hot ring, structural changes and upgrades.
  They also cover the possible failures that happened on the second starship test run leading to the abort. The possible unintended consequences of the tilt of the grid fins to aid in turning the booster? (as we speculated before, a weakness causing mixing between the fuel and oxygen is the leading explanation of the point of failure)
  An hour and 20 minutes but very informative.
  https://www.youtube.com/watch?v=ZIisBG3NV8Y

  I was imagining what could cure the problem of damage from negative thrust to a sudden 3 gravity‘s when 10 tons of 02 propellant come slamming down on the bottom of the tank? (sloshing)

  Ratcheting baffles that move down during fuel consumption can only work if the walls are smooth, I believe the best solution is if they make the header tank and descending supply line for methane, re-engineered into a smooth one piece tank inside of the oxygen tank running the length of the rocket!
  Not only will baffles be doable, but the thickness/weight of the walls of inner tank could be reduced due to the oxygen pressure against the tank walls. As the oxygen is being consumed, it’s boil point it’s colder than methane which could lead to freezing of the methane… prevention methods like insulation to lessen the chance of icing or chunks of ice making it into the turbo pump may be necessary? It would be worth it for better control of unintended sloshing, less points of failure.

  There is the added benefit of better control methods during refueling in weightlessness. (The tanker, without this modification, would require minimum directional gravity thrust to keep the fluid in the pump suction port without the clamps that locks the two vessels together from failing)

  I still believe the current design is adequate if they put thrusters (as designed for lunar/Mars landing) just under the crew quarters of starship and use those during separation. This way they can eliminate the hot ring and it’s considerable weight. (they cover the weight in the above video)

  Throttle back booster to one gimbaled motor with a quarter to a half G thrust, while starship side thrusters initiate separation at two gees giving some space before igniting main motors. Economical, safe and effective.
  This is the future of all landing craft, until a better design comes along. (current design is for atmospheric use, future construction in/for vacuum will be better suited as landing platforms with elevated landing thrusters aimed away to prevent dust/rock kickback which damages the lander… and not requiring elevators to reach the surface)
• J Fincannon

  March 5, 2024 at 8:35 am

  Robert!
  It sounds like you were a veritable Superman in helping Dr. Space through his hacker woes. His tribute to you on his web site is well deserved. Thanks for your efforts.
  James