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This is pretty interesting, but Id be surprised if it actually happens on the next flight. Depending on the cost of the tanks/fittings/machines, it could be a f

This is pretty interesting, but Id be surprised if it actually happens on the next flight. Depending on the cost of the tanks/fittings/machines, it could be a fairly expensive loss if Starship doesnt reach orbit, which seems fairly likely still. Their last launch was impressive, but Id be wary to put a payload worth more than a few pennies on the next launch

BryanLegend 3y ago
It's fantastic that the Super Heavy booster fully completed it's mission! Much bigger deal than the ship itself failing. Before that last flight it seemed like engine reliability wouldn't get solved. But now they have a clear path to orbit. I doubt the heat shields will hold up on the first several re-entry attempts but there's been recent sightings of a new heat shield that has tiles about half the size. Maybe smaller tiles will have less lever action and will have 4x the fasteners.
- ramesh31 3y ago
  >Maybe smaller tiles will have less lever action and will have 4x the fasteners. This is still the number one problem with Starship. There were all these wild claims of an exotic new liquid cooled reentry system at the beginning. But because physics they ended up going right back to using ablative. They'll suffer the same fate as the shuttle for it. Nothing has fundamentally changed in ceramic or adhesive technology since then, and the lack of aerodynamic control means they will have to survive even steeper descents with greater thermal load. I imagine the idea of Starship as an earth return vehicle in general will probably be abandoned, so they can optimize it for interplanetary transport and lunar operations.
  - tekla 3y ago
    Of course the problem with this post is that the Starship heat shield isn't ablative, nor does it share the problems with the Orbiter heat shield (Needing glue to attach every single unique tile to the body of the ship.) > the lack of aerodynamic control There are literally wings on the ship.
    - ta1243 3y ago
      I had to read it twice as I saw "lack of aerodynamic control" and assumed they meant the Shuttle, which was about as aerodynamic as a squirrel
      - lstodd 3y ago
        Well in fact at about 4:1 glide ratio subsonic it was much better than Siberian Flying Squirrels which are usually about 1.5. https://en.wikipedia.org/wiki/Siberian_flying_squirrel https://en.wikipedia.org/wiki/Siberian_flying_squirrel
    - ramesh31 3y ago
      >Starship heat shield isn't ablative Yes, it is. There is no such thing as a non-ablative reentry vehicle. The tiles are effectively no different than what was used on the shuttle. >There are literally wings on the ship. Starship has no meaningful aerodynamic control beyond what is required to perform the flip. It has no ailerons or elevators. It falls to the earth in a completely ballistic trajectory.
      - danbruc 3y ago
        Insulating tiles are not an ablative heat shield, they are a thermal soak heat shield. Ablative heat shields are non-reusable as they work by slowly burning off material which creates a cooler boundary layer between the plasma and the heat shield. [1] [1] https://en.wikipedia.org/wiki/Heat_shield#Spacecraft https://en.wikipedia.org/wiki/Heat_shield#Spacecraft
        rpmisms 3y ago
        Ablation will still happen, but the tiles aren't designed to ablate as the primary method of heat dissipation.
        danbruc 3y ago
        Sure, everything going through the atmosphere at supersonic speeds will lose at the very least a couple of atoms here and there, but that was not the point and that does not make thermal protection tiles an ablative heat shield.
  - deleted 3y ago
    [deleted]
  - idontwantthis 3y ago
    Neither the space shuttle nor Starship use ablative heat shield tiles.
    - ramesh31 3y ago
      >Neither the space shuttle nor Starship use ablative heat shield tiles. They are effectively ablative in the sense that neither vehicle has (or will) be able to complete successive missions without massive replacement of damaged and missing tiles. The fundamental approach is not suitable to reusability, as we learned with the shuttle.
      - idontwantthis 3y ago
        You might end up right but that’s still not what ablative means.
      - timschmidt 3y ago
        Shuttle tiles were unique, and glued in place. Starship tiles are mostly identical, and secured with steel spring pins.
      - tekla 3y ago
        The heat shield is not ablative. You are simply wrong.
      - 0xfae 3y ago
        What you are doing is effectively mental gymnastics to avoid admitting you used the incorrect word.
        plorg 3y ago
        That could be because there are a dozen replies fixated on the use of the wrong word and maybe one that responds to the substance of the comment.
      - panick21_ 3y ago
        First of all, that's not what ablative means. Tiles potentially falling of does not make the heat shield ablative. Because tiles falling off is not a the heat transfer mechanism, rather a mechanical failure. The Dragon Capsule for example has an Ablative Heat-Shield. But that doesn't necessarily mean it can't do multiple missions in a row. It just depends on how the shield is designed. The Dragon could potentially do many earth missions without replacing the heat shield. Second, you are wrong in that there is anything fundamental about Starship or Shuttle heat shield not being able to fly multiple missions. If the tiles are still attached and not damaged, then all that has to happen is for the tiles to cool down. After that they are ready for another flight, meaning the tiles are not ablative. Now experience on Shuttle has shown that if you are not careful tiles could fall of or be damaged. Damage can be reduced in various was and Starship without an external tank is already much better by design. Additionally Shuttle had to glue tiles to a fragile aluminum frame making the installation very hard and the tiles very fragile. Starship on the other hand uses welded studs on a steel frame. So even if a tile is lots, the steel should still hold up pretty well. In on case Shuttle was saved because there just so happened to be steel under a damaged tile. So you are right, heat shield is one of the biggest issue that could cause problems with rapid reputability. You are wrong, the tiles are not ablative cooled. But Starship tiles are totally different then Shuttles, they have made many improvements in the heat shield and its construction and in the heat shield tiles themselves. Starship can likely survive even with a number of missing tiles if required. In some position tile lose can certainty be fatal.
  - p1mrx 3y ago
    > I imagine the idea of Starship as an earth return vehicle in general will probably be abandoned, so they can optimize it for interplanetary transport and lunar operations. Starship will need several launches of methane+oxygen to travel beyond LEO. That model requires a reusable orbital tanker to make sense economically.
    - imtringued 3y ago
      Most of the engines are on the booster. The upper stage is the cheapest part of the entire rocket. At a worst case of 2 million per engine you're talking about 66 million dollars for the booster. I honestly don't understand this whole post chain. The booster needs to survive because it is the most valuable part of the rocket and yet we are supposed to praise it for exploding? The hot staging concept isn't viable over the long term because it goes counter to the goals of reusability. I don't need people to rewrite history by claiming that if the booster of the SLS exploded, it would be considered a success since nobody intends to reuse it. Yeah, that is how you get a two billion dollar launch tag. You can't convince congress to drop the SLS if you keep losing boosters.
      - p1mrx 3y ago
        They attempted a novel hot staging sequence where the booster grid fins interact with the second stage exhaust to rotate the booster. The booster rotated too violently, and shook up the tanks like a can of beer before exploding. They need to improve the control systems so the rotation happens more smoothly. I wouldn't praise the booster for exploding, but I would praise the engineers for getting it all the way to staging without engine failures. That's all most boosters are expected to do. SLS isn't expected to explode because it's based on space shuttle parts that stopped exploding decades ago.
  - panick21_ 3y ago
    > There were all these wild claims of an exotic new liquid cooled reentry system at the beginning. Its not that wild. That technology is likely used on certain military equipment. I was certainty something not tested at that scale but it wasn't a crazy thing to think about. > But because physics they ended up going right back to using ablative. They are not ablative. > Nothing has fundamentally changed in ceramic or What's your evidence? Have you done lots of study on Space Heat shield? Please share your findings. > adhesive technology since then That just wrong. Starship uses mostly welded studs steel frame. Totally different from Shuttle. > and the lack of aerodynamic control They have sufficient aerodynamic control. What evidence do you have that they don't? They have shown simulation of this before. I'm gone go with SpaceX on this unless you show me some simulation that shows insufficient control.
- idlewords 3y ago
  That 'clear path to orbit' depends on what the performance of the raptor engines is, as flown. Getting the first stage to work on all engines was a big achievement, but how effectively those engines are working is another big part of the puzzle.
SCM-Enthusiast 3y ago
That's the whole philosophy of spaceX and explicitly starship though, right? I mean they literally lauched a water tank up 100 feet and hovered it back down as a demo, then immediately scrapped it and proceeded to build 27 Starships, when not a single one has reached orbit. building the header tanks in the first place, and testing them is the interation style. If the starship blows up, the header tanks are the least of your worries.
- adolph 3y ago
  > they literally lauched a water tank up 100 feet and hovered it back down as a demo, then immediately scrapped it Are you referring to Starhopper? It is still present at Starbase as of recently. https://www.google.com/maps/place/Starhopper/@25.9977631,-97.1562322,3a https://www.google.com/maps/place/Starhopper/@25.9977631,-97...
  - pixl97 3y ago
    They may have been thinking of SN5.
bell-cot 3y ago
Compared to the base cost of the next launch, putting a bunch of experimental tanks / pipes / valves / etc. in the upper stage's cargo bay would be dirt cheap. And "time is money" - if you want to develop $ComplexTech fast, then you should start doing R&D work as soon as physically possible.
spikels 3y ago
Faulty assumptions and logic. The “payload” is an experiment that is at most two tanks, a valve and monitoring equipment. However it is pretty clear they will use the existing LOX main and header tanks and valves already present in every Starship. This will meet the requirements of NASA’s 2020 $53 million challenge to “transfer 10 metric tons of cryogenic propellant, specifically liquid oxygen, between tanks on a Starship vehicle”[1] as the smaller header tank holds roughly 20 tons. If you are already attempting to get into orbit it makes sense to include this experiment in case you succeed because you save the time and cost of an entire launch and might get a $53 million award while advancing a key requirement for HLS, a $2.9 billion dollar contract and the current core mission. This experiment has been planned for years, Starship was designed to do it and it makes sense to do it now. SpaceX clearly knows what they are doing. Unfortunately HN is terrible on this subject. [1] https://www.nasa.gov/technology/2020-nasa-tipping-point-selections/ https://www.nasa.gov/technology/2020-nasa-tipping-point-sele...
- Tuna-Fish 3y ago
  Cryogenic fuel transfer requires a bit more than that. The big issue is that unlike all fuel that has been moved between tanks in microgravity in the past, SpaceX isn't storing their fuel in a flexible tank. Instead, they have the fuel and the pressurant gas in the same tank. Under acceleration (gravity or otherwise), this is not a problem, because the fuel pools naturally "down", with the pressurant above it. However, as soon as the acceleration stops, there is no more down. Instead of having a bunch of fuel on the bottom and pressurant above, the tank will contain a chaotic mixture of floating gas and liquid. The minimum setup for fuel transfer is a maneuvering system capable of a very long, weak impulse (to provide down), and then some kind of pump that moves fuel, because the force provided by the weak impulse of a maneuvering thruster is not enough to do it on it's own.
  - pokey00 3y ago
    Your maneuvering system just needs to be able to get tanks spinning.
    - deleted 3y ago
idlewords 3y ago
It sounds like it's part of their contractual obligation to NASA. HLS can't fly without it, so they need to demonstrate the ability ASAP.
panick21_ 3y ago
Not sure what you mean. They have to have this stuff on each Starship anyways. And they need to learn how to build that stuff. Its already built into the next Starship. And that ship (in fact the next 4) have no other reason to exist other then testing these things. The ship is the payload. The testing is inside of the tanks of the ship. Moving fuel around inside the ship. There is no extra expensive payload in addition to the ship.

BryanLegend 3y ago

It's fantastic that the Super Heavy booster fully completed it's mission! Much bigger deal than the ship itself failing. Before that last flight it seemed like engine reliability wouldn't get solved. But now they have a clear path to orbit. I doubt the heat shields will hold up on the first several re-entry attempts but there's been recent sightings of a new heat shield that has tiles about half the size. Maybe smaller tiles will have less lever action and will have 4x the fasteners.

ramesh31 3y ago
>Maybe smaller tiles will have less lever action and will have 4x the fasteners. This is still the number one problem with Starship. There were all these wild claims of an exotic new liquid cooled reentry system at the beginning. But because physics they ended up going right back to using ablative. They'll suffer the same fate as the shuttle for it. Nothing has fundamentally changed in ceramic or adhesive technology since then, and the lack of aerodynamic control means they will have to survive even steeper descents with greater thermal load. I imagine the idea of Starship as an earth return vehicle in general will probably be abandoned, so they can optimize it for interplanetary transport and lunar operations.
- tekla 3y ago
  Of course the problem with this post is that the Starship heat shield isn't ablative, nor does it share the problems with the Orbiter heat shield (Needing glue to attach every single unique tile to the body of the ship.) > the lack of aerodynamic control There are literally wings on the ship.
  - ta1243 3y ago
    I had to read it twice as I saw "lack of aerodynamic control" and assumed they meant the Shuttle, which was about as aerodynamic as a squirrel
    - lstodd 3y ago
      Well in fact at about 4:1 glide ratio subsonic it was much better than Siberian Flying Squirrels which are usually about 1.5. https://en.wikipedia.org/wiki/Siberian_flying_squirrel https://en.wikipedia.org/wiki/Siberian_flying_squirrel
  - ramesh31 3y ago
    >Starship heat shield isn't ablative Yes, it is. There is no such thing as a non-ablative reentry vehicle. The tiles are effectively no different than what was used on the shuttle. >There are literally wings on the ship. Starship has no meaningful aerodynamic control beyond what is required to perform the flip. It has no ailerons or elevators. It falls to the earth in a completely ballistic trajectory.
    - danbruc 3y ago
      Insulating tiles are not an ablative heat shield, they are a thermal soak heat shield. Ablative heat shields are non-reusable as they work by slowly burning off material which creates a cooler boundary layer between the plasma and the heat shield. [1] [1] https://en.wikipedia.org/wiki/Heat_shield#Spacecraft https://en.wikipedia.org/wiki/Heat_shield#Spacecraft
      - rpmisms 3y ago
        Ablation will still happen, but the tiles aren't designed to ablate as the primary method of heat dissipation.
        danbruc 3y ago
        Sure, everything going through the atmosphere at supersonic speeds will lose at the very least a couple of atoms here and there, but that was not the point and that does not make thermal protection tiles an ablative heat shield.
- deleted 3y ago
  [deleted]
- idontwantthis 3y ago
  Neither the space shuttle nor Starship use ablative heat shield tiles.
  - ramesh31 3y ago
    >Neither the space shuttle nor Starship use ablative heat shield tiles. They are effectively ablative in the sense that neither vehicle has (or will) be able to complete successive missions without massive replacement of damaged and missing tiles. The fundamental approach is not suitable to reusability, as we learned with the shuttle.
    - idontwantthis 3y ago
      You might end up right but that’s still not what ablative means.
    - timschmidt 3y ago
      Shuttle tiles were unique, and glued in place. Starship tiles are mostly identical, and secured with steel spring pins.
    - tekla 3y ago
      The heat shield is not ablative. You are simply wrong.
    - 0xfae 3y ago
      What you are doing is effectively mental gymnastics to avoid admitting you used the incorrect word.
      - plorg 3y ago
        That could be because there are a dozen replies fixated on the use of the wrong word and maybe one that responds to the substance of the comment.
    - panick21_ 3y ago
      First of all, that's not what ablative means. Tiles potentially falling of does not make the heat shield ablative. Because tiles falling off is not a the heat transfer mechanism, rather a mechanical failure. The Dragon Capsule for example has an Ablative Heat-Shield. But that doesn't necessarily mean it can't do multiple missions in a row. It just depends on how the shield is designed. The Dragon could potentially do many earth missions without replacing the heat shield. Second, you are wrong in that there is anything fundamental about Starship or Shuttle heat shield not being able to fly multiple missions. If the tiles are still attached and not damaged, then all that has to happen is for the tiles to cool down. After that they are ready for another flight, meaning the tiles are not ablative. Now experience on Shuttle has shown that if you are not careful tiles could fall of or be damaged. Damage can be reduced in various was and Starship without an external tank is already much better by design. Additionally Shuttle had to glue tiles to a fragile aluminum frame making the installation very hard and the tiles very fragile. Starship on the other hand uses welded studs on a steel frame. So even if a tile is lots, the steel should still hold up pretty well. In on case Shuttle was saved because there just so happened to be steel under a damaged tile. So you are right, heat shield is one of the biggest issue that could cause problems with rapid reputability. You are wrong, the tiles are not ablative cooled. But Starship tiles are totally different then Shuttles, they have made many improvements in the heat shield and its construction and in the heat shield tiles themselves. Starship can likely survive even with a number of missing tiles if required. In some position tile lose can certainty be fatal.
- p1mrx 3y ago
  > I imagine the idea of Starship as an earth return vehicle in general will probably be abandoned, so they can optimize it for interplanetary transport and lunar operations. Starship will need several launches of methane+oxygen to travel beyond LEO. That model requires a reusable orbital tanker to make sense economically.
  - imtringued 3y ago
    Most of the engines are on the booster. The upper stage is the cheapest part of the entire rocket. At a worst case of 2 million per engine you're talking about 66 million dollars for the booster. I honestly don't understand this whole post chain. The booster needs to survive because it is the most valuable part of the rocket and yet we are supposed to praise it for exploding? The hot staging concept isn't viable over the long term because it goes counter to the goals of reusability. I don't need people to rewrite history by claiming that if the booster of the SLS exploded, it would be considered a success since nobody intends to reuse it. Yeah, that is how you get a two billion dollar launch tag. You can't convince congress to drop the SLS if you keep losing boosters.
    - p1mrx 3y ago
      They attempted a novel hot staging sequence where the booster grid fins interact with the second stage exhaust to rotate the booster. The booster rotated too violently, and shook up the tanks like a can of beer before exploding. They need to improve the control systems so the rotation happens more smoothly. I wouldn't praise the booster for exploding, but I would praise the engineers for getting it all the way to staging without engine failures. That's all most boosters are expected to do. SLS isn't expected to explode because it's based on space shuttle parts that stopped exploding decades ago.
- panick21_ 3y ago
  > There were all these wild claims of an exotic new liquid cooled reentry system at the beginning. Its not that wild. That technology is likely used on certain military equipment. I was certainty something not tested at that scale but it wasn't a crazy thing to think about. > But because physics they ended up going right back to using ablative. They are not ablative. > Nothing has fundamentally changed in ceramic or What's your evidence? Have you done lots of study on Space Heat shield? Please share your findings. > adhesive technology since then That just wrong. Starship uses mostly welded studs steel frame. Totally different from Shuttle. > and the lack of aerodynamic control They have sufficient aerodynamic control. What evidence do you have that they don't? They have shown simulation of this before. I'm gone go with SpaceX on this unless you show me some simulation that shows insufficient control.
idlewords 3y ago
That 'clear path to orbit' depends on what the performance of the raptor engines is, as flown. Getting the first stage to work on all engines was a big achievement, but how effectively those engines are working is another big part of the puzzle.

SCM-Enthusiast 3y ago

That's the whole philosophy of spaceX and explicitly starship though, right? I mean they literally lauched a water tank up 100 feet and hovered it back down as a demo, then immediately scrapped it and proceeded to build 27 Starships, when not a single one has reached orbit. building the header tanks in the first place, and testing them is the interation style. If the starship blows up, the header tanks are the least of your worries.

adolph 3y ago
> they literally lauched a water tank up 100 feet and hovered it back down as a demo, then immediately scrapped it Are you referring to Starhopper? It is still present at Starbase as of recently. https://www.google.com/maps/place/Starhopper/@25.9977631,-97.1562322,3a https://www.google.com/maps/place/Starhopper/@25.9977631,-97...
- pixl97 3y ago
  They may have been thinking of SN5.

bell-cot 3y ago

Compared to the base cost of the next launch, putting a bunch of experimental tanks / pipes / valves / etc. in the upper stage's cargo bay would be dirt cheap. And "time is money" - if you want to develop $ComplexTech fast, then you should start doing R&D work as soon as physically possible.

spikels 3y ago

Faulty assumptions and logic. The “payload” is an experiment that is at most two tanks, a valve and monitoring equipment. However it is pretty clear they will use the existing LOX main and header tanks and valves already present in every Starship. This will meet the requirements of NASA’s 2020 $53 million challenge to “transfer 10 metric tons of cryogenic propellant, specifically liquid oxygen, between tanks on a Starship vehicle”[1] as the smaller header tank holds roughly 20 tons. If you are already attempting to get into orbit it makes sense to include this experiment in case you succeed because you save the time and cost of an entire launch and might get a $53 million award while advancing a key requirement for HLS, a $2.9 billion dollar contract and the current core mission. This experiment has been planned for years, Starship was designed to do it and it makes sense to do it now. SpaceX clearly knows what they are doing. Unfortunately HN is terrible on this subject. [1] https://www.nasa.gov/technology/2020-nasa-tipping-point-selections/ https://www.nasa.gov/technology/2020-nasa-tipping-point-sele...

Tuna-Fish 3y ago
Cryogenic fuel transfer requires a bit more than that. The big issue is that unlike all fuel that has been moved between tanks in microgravity in the past, SpaceX isn't storing their fuel in a flexible tank. Instead, they have the fuel and the pressurant gas in the same tank. Under acceleration (gravity or otherwise), this is not a problem, because the fuel pools naturally "down", with the pressurant above it. However, as soon as the acceleration stops, there is no more down. Instead of having a bunch of fuel on the bottom and pressurant above, the tank will contain a chaotic mixture of floating gas and liquid. The minimum setup for fuel transfer is a maneuvering system capable of a very long, weak impulse (to provide down), and then some kind of pump that moves fuel, because the force provided by the weak impulse of a maneuvering thruster is not enough to do it on it's own.
- pokey00 3y ago
  Your maneuvering system just needs to be able to get tanks spinning.
  - deleted 3y ago

idlewords 3y ago

It sounds like it's part of their contractual obligation to NASA. HLS can't fly without it, so they need to demonstrate the ability ASAP.

panick21_ 3y ago

Not sure what you mean. They have to have this stuff on each Starship anyways. And they need to learn how to build that stuff. Its already built into the next Starship. And that ship (in fact the next 4) have no other reason to exist other then testing these things. The ship is the payload. The testing is inside of the tanks of the ship. Moving fuel around inside the ship. There is no extra expensive payload in addition to the ship.