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Yes but in real life they are not necessarily landing in the same spot the same day to be reused again. They could have multiple replacement boosters. Regard

Yes but in real life they are not necessarily landing in the same spot the same day to be reused again. They could have multiple replacement boosters. Regardless, I have no problem with the booster return design unless it induces reckless danger to human life. The explosion is not a positive data.

gridspy 6y ago
Given two options 1. People doing analysis and hoping to check everything through engineering rigor and (hopefully) good assumptions 2. Test early and often, learning along the way until many positive tests have proven the system I'd prefer 2. Look at systems like SLS to see the schedule results of (1). No people were put on Falcon launches until almost 100 successful launches. I imagine a similar situation for StarShip. For example NASA is funding in orbit refuelling experiments (unmanned) and also a StarShip moon landing (unmanned) which will help prove the system prior to human flight. Don't worry, plenty of people will carefully do analysis (1) later on. But the data they will review will include telemetry from real flights rather than just hopeful simulation / analysis results.
- GizmoSwan 6y ago
  Don't get your hopes up. Since it is rotating on an axis while moving and twice, it has a huge degree of freedom for failure. Even if successfully returns 100 times, any untested change to its payload can change the parameters which are apparently unknown because they have not used any fancy simulation. Good luck. I will be watching and ready to say I told you so. The staff could be absolute geniuses by they will not be able to foresee all the unexpected results.
  - gridspy 6y ago
    The failures so far relate to the pressurization of the header tanks and the engine performance on re-light (hard problems). I imagine these will be well solved after 100 flights. The assumption that shifting payload is going to boggle the flight computers leading to loss of craft sounds unlikely. Both because the payload will be secured and the flight computers are more dynamic than that. Finally, the forces on the cargo shift from 1G towards the belly during the belly flop to a mix of gravity and pressure from the engines during the flip. While the view from the window would be "interesting" - the actual forces on the payload will remain a summed ~2G from these two axes (mostly from "down") during landing. This is similar to how the lift vector while rolling in an aircraft keeps you safely stuck to the floor (and not the walls) during jet flight. Anyone flying an aircraft or space vehicle who doesn't secure their loads is going to experience some shifting of cargo. Of course that's why you have a small cargo compartment which physically restricts the movement of potential cargo. See how 747s secure cargo in large bins within a dedicated cargo hold for reference.
    - GizmoSwan 6y ago
      747 can not flip like that; it would stall and crash. The narrow bodied 737s crashed for less. Their fancy flight computer miscalculated because of center of gravity miscalculations. They crashed after 100s of flights. I like your optimism. Good luck. I mean it. I would not fly in that thing even if they paid me a million. Sorry for my lack of faith.
      - avmich 6y ago
        Big airliners do parabolic arcs - "vomit comet", so it's not a huge problem. 737 MAX crashed for different reasons. E.g. Soyuz capsule returns safely despite different loads and different distributions of mass - control systems, even relatively modest ones, can compensate. It's failures which provide most useful information about shortcomings of the system at some point, so they are welcome during testing - if you think that at this point they shouldn't explode, you'd better bring good arguments. Shuttle had much better aerodynamic shape than Starship, and their landing modes are different.
        GizmoSwan 6y ago
        737-max crashed because they never went through full blown simulation and acceptance procedures for it. They just made the body longer and compensated for differentials in flight control software parameters but they had a blind spot in their assumptions. Those aircrafts have decades of air flight simulation behind them and yet .... Shuttle is a much finer craft but these guys may have different objectives and that is their prerogative. The fact that there are errors in there that can lead to explosion is troubling to me. The claim that the explosions will lead towards a better design is an assumption.
        gridspy 6y ago
        737-Max crashed because of the "lets analyse this rather than test it" thinking that you described earlier. That and an overly cosy relationship with the FCC and a culture of silencing cautious engineering voices. It's seemed cheaper to tack larger engines and new software onto the old air-frame than to redesign the aircraft to be mechanically stable and update the cockpit. Not surprising that the same company (Boeing) that campaigned for analysis over testing in spaceship design (they claimed SpaceX couldn't do commercial crew) also failed to design a working and stable aircraft. I'd argue that the bureaucracy involved in "signing off" an new aircraft design contributed to these problems. Designing a aircraft or spacecraft from first principles and then refining through testing does have its advantages. My point about aircraft was that the lift vector is perpendicular to the wings, even if the aircraft flips (rolls) upside-down there is still a force that pushes you toward the deck if you are inside the plane. In the StarShip there is a similar upwards force from the engines (when lit) towards the nose regardless of which direction the ship is oriented with respect to the Earth. The reason why flying a plane in clouds is so dangerous is that your sense of up and down in a plane is invalid. You'll always think the deck is down without the aid of either a view of the horizon or the correct use of functioning instrumentation.

gridspy 6y ago

Given two options 1. People doing analysis and hoping to check everything through engineering rigor and (hopefully) good assumptions 2. Test early and often, learning along the way until many positive tests have proven the system I'd prefer 2. Look at systems like SLS to see the schedule results of (1). No people were put on Falcon launches until almost 100 successful launches. I imagine a similar situation for StarShip. For example NASA is funding in orbit refuelling experiments (unmanned) and also a StarShip moon landing (unmanned) which will help prove the system prior to human flight. Don't worry, plenty of people will carefully do analysis (1) later on. But the data they will review will include telemetry from real flights rather than just hopeful simulation / analysis results.

GizmoSwan 6y ago
Don't get your hopes up. Since it is rotating on an axis while moving and twice, it has a huge degree of freedom for failure. Even if successfully returns 100 times, any untested change to its payload can change the parameters which are apparently unknown because they have not used any fancy simulation. Good luck. I will be watching and ready to say I told you so. The staff could be absolute geniuses by they will not be able to foresee all the unexpected results.
- gridspy 6y ago
  The failures so far relate to the pressurization of the header tanks and the engine performance on re-light (hard problems). I imagine these will be well solved after 100 flights. The assumption that shifting payload is going to boggle the flight computers leading to loss of craft sounds unlikely. Both because the payload will be secured and the flight computers are more dynamic than that. Finally, the forces on the cargo shift from 1G towards the belly during the belly flop to a mix of gravity and pressure from the engines during the flip. While the view from the window would be "interesting" - the actual forces on the payload will remain a summed ~2G from these two axes (mostly from "down") during landing. This is similar to how the lift vector while rolling in an aircraft keeps you safely stuck to the floor (and not the walls) during jet flight. Anyone flying an aircraft or space vehicle who doesn't secure their loads is going to experience some shifting of cargo. Of course that's why you have a small cargo compartment which physically restricts the movement of potential cargo. See how 747s secure cargo in large bins within a dedicated cargo hold for reference.
  - GizmoSwan 6y ago
    747 can not flip like that; it would stall and crash. The narrow bodied 737s crashed for less. Their fancy flight computer miscalculated because of center of gravity miscalculations. They crashed after 100s of flights. I like your optimism. Good luck. I mean it. I would not fly in that thing even if they paid me a million. Sorry for my lack of faith.
    - avmich 6y ago
      Big airliners do parabolic arcs - "vomit comet", so it's not a huge problem. 737 MAX crashed for different reasons. E.g. Soyuz capsule returns safely despite different loads and different distributions of mass - control systems, even relatively modest ones, can compensate. It's failures which provide most useful information about shortcomings of the system at some point, so they are welcome during testing - if you think that at this point they shouldn't explode, you'd better bring good arguments. Shuttle had much better aerodynamic shape than Starship, and their landing modes are different.
      - GizmoSwan 6y ago
        737-max crashed because they never went through full blown simulation and acceptance procedures for it. They just made the body longer and compensated for differentials in flight control software parameters but they had a blind spot in their assumptions. Those aircrafts have decades of air flight simulation behind them and yet .... Shuttle is a much finer craft but these guys may have different objectives and that is their prerogative. The fact that there are errors in there that can lead to explosion is troubling to me. The claim that the explosions will lead towards a better design is an assumption.
        gridspy 6y ago
        737-Max crashed because of the "lets analyse this rather than test it" thinking that you described earlier. That and an overly cosy relationship with the FCC and a culture of silencing cautious engineering voices. It's seemed cheaper to tack larger engines and new software onto the old air-frame than to redesign the aircraft to be mechanically stable and update the cockpit. Not surprising that the same company (Boeing) that campaigned for analysis over testing in spaceship design (they claimed SpaceX couldn't do commercial crew) also failed to design a working and stable aircraft. I'd argue that the bureaucracy involved in "signing off" an new aircraft design contributed to these problems. Designing a aircraft or spacecraft from first principles and then refining through testing does have its advantages. My point about aircraft was that the lift vector is perpendicular to the wings, even if the aircraft flips (rolls) upside-down there is still a force that pushes you toward the deck if you are inside the plane. In the StarShip there is a similar upwards force from the engines (when lit) towards the nose regardless of which direction the ship is oriented with respect to the Earth. The reason why flying a plane in clouds is so dangerous is that your sense of up and down in a plane is invalid. You'll always think the deck is down without the aid of either a view of the horizon or the correct use of functioning instrumentation.