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Why would you want to test if you could refuel a rocket that keeps exploding

by Kapura 3y ago

cratermoon 3y ago
It does seem like quite a leap from the FTS triggering before reaching orbit to refueling, doesn't it? My hunch is that whatever happens, we'll see scenes of SpaceX people clapping and cheering and SpaceX fans calling the flight a success. From what they tell me, no SpaceX launch has ever failed.
- ceejayoz 3y ago
  No one's going to argue https://en.wikipedia.org/wiki/SpaceX_CRS-7 https://en.wikipedia.org/wiki/SpaceX_CRS-7 wasn't a failure. That's a production flight that went ka-boom with a lost payload. Test flights are a very different beast. Early tests can be expected to fail; some are supposed to fail ("destructive testing"). Explosions and other failures become much more concerning later in the process; for example, Boeing's Starliner's latest test flight was supposed to demonstrate everything was working correctly. It failed to do so. In the two Starship launches so far, SpaceX was very clear with expectations in advance. Each likely has dozens of objectives. The second flight very clearly accomplished more than the first; a successful test of the launchpad mitigations, a successful test of all first-stage engines staying lit, a successful test of separation, a successful test of the second-stage engines all lighting, etc.
  - me_me_me 3y ago
    how come people with sliding rulers and navigation computers 'knitted' by local grannies have lost 0 Saturn rockets. But now an explosion is an expected outcome for your million dollar hardware. That approach works in software dev.
    - pixl97 3y ago
      Because Saturn rockets cost 1.3 billion dollars EACH. A test starship is nowhere near that, though we don't have exact numbers. Probably closer to $100 million. Also SpaceX is trying to solve a much harder problem. If you would have asked that Saturn team "Also, land all the stages of the rocket", the likely answer you would have got is "Screw off, you're insane" or "Give me 100 billion dollars".
      - XorNot 3y ago
        Also getting Raptor engines to work. The second Starship test was a massive achievement because the SuperHeavy Raptors all worked. That's an engine design with numerous advantages which wasn't practical when the Russians tried it, but might now be practical (certainly looks to be from the test) because control systems technology is small and powerful enough (i.e. similar to how modern fighter jets fly in aerodynamically unstable regimes requiring active computer control - we have them now because we have the computers which can do it).
    - jzombie 3y ago
      If you're exploding million dollar hardware w/ your software development, maybe it's time to change careers.
    - ceejayoz 3y ago
      > how come people with sliding rulers and navigation computers 'knitted' by local grannies have lost 0 Saturn rockets. The fuck? NASA lost people in production hardware multiple times. https://en.wikipedia.org/wiki/Apollo_1 https://en.wikipedia.org/wiki/Apollo_1 https://en.wikipedia.org/wiki/Apollo_6 https://en.wikipedia.org/wiki/Apollo_6 "The damaged third-stage engine failed to restart for trans-lunar injection... Despite the engine failures, the flight provided NASA with enough confidence to use the Saturn V for crewed launches..." https://en.wikipedia.org/wiki/Apollo_13 https://en.wikipedia.org/wiki/Apollo_13 https://en.wikipedia.org/wiki/Space_Shuttle_Challenger_disaster https://en.wikipedia.org/wiki/Space_Shuttle_Challenger_disas... https://en.wikipedia.org/wiki/Space_Shuttle_Columbia_disaster https://en.wikipedia.org/wiki/Space_Shuttle_Columbia_disaste... Here's a fun one: They tested the Saturn crew escape system. The booster was supposed to blow up, and demonstrate the crew would survive... but the test went wrong, and it blew up early, when it shouldn't have. The crew abort worked, so test failed successfully. https://www.youtube.com/watch?v=AqeJzItldSQ https://www.youtube.com/watch?v=AqeJzItldSQ
      - angiosperm 3y ago
        Apollo 1 was very much not production hardware. "The Vintage Space" channel on YT has a good rundown, "Duplicate Apollo Spacecraft". They didn't lose any crew on production hardware, although 13 was close.
        mulmen 3y ago
        AS-204 was absolutely production hardware. The later hardware was different because three people died. They died in rehearsal for an actual mission. > Apollo 1, initially designated AS-204, was planned to be the first crewed mission of the Apollo program. https://en.m.wikipedia.org/wiki/Apollo_1 https://en.m.wikipedia.org/wiki/Apollo_1
        angiosperm 3y ago
        The second version was already starting production when three people died. There was never any intention to build any more of the first one, or to send it beyond low Earth orbit.
    - philwelch 3y ago
      Every Saturn rocket was lost.
      - angiosperm 3y ago
        We know right where each came down.
    - inglor_cz 3y ago
      a) Those people with sliding rulers and navigation computers also had 2.5 % of American GDP annually at their disposal, which is several orders of magnitude more than anyone now has. (Be it SpaceX or Boeing or whoever...) b) The Apollo program actually cost not just money, but human lives = a much worse outcome than just losing a test rocket. And Apollo 13 crew was very lucky to have returned to Earth alive. c) Losses of test hardware can only really be somewhat prevented by being extremely careful and pedantic during development, which takes time, and guess what? More time spent obsessing about every single detail = more money spent on development. It is entirely possible that the "hardware is expendable" approach is much cheaper than what you would like to have.
  - cratermoon 3y ago
    If a test flight doesn't achieve the testing objectives, that's a failure. No one would argue that failing to find a bug before putting software in production was a testing success just because all the tests executed without errors.
    - ceejayoz 3y ago
      > If a test flight doesn't achieve the testing objectives, that's a failure. Demonstrably incorrect. Examples: https://www.youtube.com/watch?v=AqeJzItldSQ https://www.youtube.com/watch?v=AqeJzItldSQ is a Saturn launch abort test that failed. It failed in a way that they were able to determine that intended test would have worked, though. 1:20 for the meat of things. https://en.wikipedia.org/wiki/Apollo_6 https://en.wikipedia.org/wiki/Apollo_6 also failed to achieve its objectives; "Despite the engine failures, the flight provided NASA with enough confidence to use the Saturn V for crewed launches; a potential third uncrewed flight was cancelled." All that aside, SpaceX was quite clear that the latest Starship test had multiple objectives, and that "successfully splashdown near Hawaii" was deemed quite unlikely. It successfully demonstrated a number of items, including fairly critically the launchpad changes. It wasn't one test; it was a bunch of tests in one flight.
    - gpm 3y ago
      There are multiple categories of objectives... Objectives that motivated the test flight. Objectives that are expected to succeed. Objectives that you threw on because "if the $xx million object is still intact it would be nice to get some useful data, and the FAA wants a complete flight plan anyways". If that last category doesn't succeed that doesn't mean the test flight was a "failure" from the businesses perspective. They still got what they wanted, they just didn't get the icing on top. The test flight that destroyed the pad is properly categorized as a failure. The flight termination system was expected to work. They expected not to cause that much damage to their infrastructure and surroundings, their relationship with the FAA, their ability to get licenses, etc. To argue that it wasn't a failure, you have to argue that the flight termination system was in the category of systems where a failure was considered acceptable. If that was the case, everyone involved in launching that flight ought to to go jail for recklessly endangering the public. The most recent test flight though seems to have been a pretty resounding success. Everything that they said they really wanted to see happen, happened. Yes, both stages had failures in "we might not even get here" test objectives after that. That's ok.
- stoneman24 3y ago
  If I remember correctly there has been a couple of falcon failures, it should be noted that the starship project is is still well in the development phase. The success criteria for integrated launch test 1 was to clear the launch pad (which it nearly destroyed) test 2 was get past the stage seperation, which it did. Spacex have a very fast cadence for tests and seem not to make the same error twice. The best test environment is really trying to fly the ship.
me_me_me 3y ago
[flagged]
- pixl97 3y ago
  How is that exactly? Launch one really was a comedy of errors in the launch platform. In launch 2 the booster did exactly what every other booster by everyone else (except the falcon 9) does. Got it's payload to the target altitude before separation. The second stage reached space. The N1 platform didn't do any of that. You have no idea what a testing platform looks like, and are too used to NASA one shot rockets that cost 3 billion each just to make sure nothing goes wrong.
  - simiones 3y ago
    The booster exploded after separation, which is never a good sign. Normal boosters for modern rockets don't do that. The second stage exploded as well, possibly because of FTS, possibly not (was it ever confirmed?).
    - jdminhbg 3y ago
      > The booster exploded after separation, which is never a good sign. Normal boosters for modern rockets don't do that. It exploded while attempting to test its landing maneuver. If it just turned off the engines and dropped itself into the ocean like a normal booster, it likely would not have exploded (for one thing, there wouldn't be any fuel left in it being saved for landing).
    - ggreer 3y ago
      Well it's not a normal booster. It's a test booster. Also normal boosters don't do a flip while getting blasted with rocket exhaust. SpaceX clearly has a winning method, as they have a success rate of 99.3% and hold the record for most consecutive successful launches at 253. Second place is Soyuz-U, which had 112 consecutive successful launches and an overall success rate of 97.3%. SpaceX has more consecutive successful booster landings (173) than any space program has had successful launches.
    - 3y ago
rodlette 3y ago
I know nothing about rockets but bits of project management: it's common to break down projects into smaller parts and derisk designs/implementations by testing each piece. The refueling team might be ready to test, even though the "don't explode" team are still working on it.
colechristensen 3y ago
This is roughly equivalent to watching a developer work and insulting them when their code doesn’t compile. Nobody who writes code cares, that’s just what writing code is like. You could spend a ton more time writing code trying to get it to compile without errors ever, but that would be a whole lot more pointless work.
- Kapura 3y ago
  Writing software and building rockets are unlike each other in many respects; the cost of small errors being high among them.
  - nomel 3y ago
    > the cost of small errors being high among them There are some great documentaries about the NASA team that does safety critical software: https://www.youtube.com/watch?v=iJNNJxC12UM https://www.youtube.com/watch?v=iJNNJxC12UM
  - marcusverus 3y ago
    There are costs and then there are trade-off costs. In the long run, the trade-off costs of slow-moving perfectionism are FAR higher than the cost of the ‘fail fast and early’ culture at SpaceX.

Why would you want to test if you could refuel a rocket that keeps exploding

by Kapura 3y ago

Why would you want to test if you could refuel a rocket that keeps exploding

It does seem like quite a leap from the FTS triggering before reaching orbit to refueling, doesn't it? My hunch is that whatever happens, we'll see scenes of SpaceX people clapping and cheering and SpaceX fans calling the flight a success. From what they tell me, no SpaceX launch has ever failed.

ceejayoz 3y ago
No one's going to argue https://en.wikipedia.org/wiki/SpaceX_CRS-7 https://en.wikipedia.org/wiki/SpaceX_CRS-7 wasn't a failure. That's a production flight that went ka-boom with a lost payload. Test flights are a very different beast. Early tests can be expected to fail; some are supposed to fail ("destructive testing"). Explosions and other failures become much more concerning later in the process; for example, Boeing's Starliner's latest test flight was supposed to demonstrate everything was working correctly. It failed to do so. In the two Starship launches so far, SpaceX was very clear with expectations in advance. Each likely has dozens of objectives. The second flight very clearly accomplished more than the first; a successful test of the launchpad mitigations, a successful test of all first-stage engines staying lit, a successful test of separation, a successful test of the second-stage engines all lighting, etc.
- me_me_me 3y ago
  how come people with sliding rulers and navigation computers 'knitted' by local grannies have lost 0 Saturn rockets. But now an explosion is an expected outcome for your million dollar hardware. That approach works in software dev.
  - pixl97 3y ago
    Because Saturn rockets cost 1.3 billion dollars EACH. A test starship is nowhere near that, though we don't have exact numbers. Probably closer to $100 million. Also SpaceX is trying to solve a much harder problem. If you would have asked that Saturn team "Also, land all the stages of the rocket", the likely answer you would have got is "Screw off, you're insane" or "Give me 100 billion dollars".
    - XorNot 3y ago
      Also getting Raptor engines to work. The second Starship test was a massive achievement because the SuperHeavy Raptors all worked. That's an engine design with numerous advantages which wasn't practical when the Russians tried it, but might now be practical (certainly looks to be from the test) because control systems technology is small and powerful enough (i.e. similar to how modern fighter jets fly in aerodynamically unstable regimes requiring active computer control - we have them now because we have the computers which can do it).
  - jzombie 3y ago
    If you're exploding million dollar hardware w/ your software development, maybe it's time to change careers.
  - ceejayoz 3y ago
    > how come people with sliding rulers and navigation computers 'knitted' by local grannies have lost 0 Saturn rockets. The fuck? NASA lost people in production hardware multiple times. https://en.wikipedia.org/wiki/Apollo_1 https://en.wikipedia.org/wiki/Apollo_1 https://en.wikipedia.org/wiki/Apollo_6 https://en.wikipedia.org/wiki/Apollo_6 "The damaged third-stage engine failed to restart for trans-lunar injection... Despite the engine failures, the flight provided NASA with enough confidence to use the Saturn V for crewed launches..." https://en.wikipedia.org/wiki/Apollo_13 https://en.wikipedia.org/wiki/Apollo_13 https://en.wikipedia.org/wiki/Space_Shuttle_Challenger_disaster https://en.wikipedia.org/wiki/Space_Shuttle_Challenger_disas... https://en.wikipedia.org/wiki/Space_Shuttle_Columbia_disaster https://en.wikipedia.org/wiki/Space_Shuttle_Columbia_disaste... Here's a fun one: They tested the Saturn crew escape system. The booster was supposed to blow up, and demonstrate the crew would survive... but the test went wrong, and it blew up early, when it shouldn't have. The crew abort worked, so test failed successfully. https://www.youtube.com/watch?v=AqeJzItldSQ https://www.youtube.com/watch?v=AqeJzItldSQ
    - angiosperm 3y ago
      Apollo 1 was very much not production hardware. "The Vintage Space" channel on YT has a good rundown, "Duplicate Apollo Spacecraft". They didn't lose any crew on production hardware, although 13 was close.
      - mulmen 3y ago
        AS-204 was absolutely production hardware. The later hardware was different because three people died. They died in rehearsal for an actual mission. > Apollo 1, initially designated AS-204, was planned to be the first crewed mission of the Apollo program. https://en.m.wikipedia.org/wiki/Apollo_1 https://en.m.wikipedia.org/wiki/Apollo_1
        angiosperm 3y ago
        The second version was already starting production when three people died. There was never any intention to build any more of the first one, or to send it beyond low Earth orbit.
  - philwelch 3y ago
    Every Saturn rocket was lost.
    - angiosperm 3y ago
      We know right where each came down.
  - inglor_cz 3y ago
    a) Those people with sliding rulers and navigation computers also had 2.5 % of American GDP annually at their disposal, which is several orders of magnitude more than anyone now has. (Be it SpaceX or Boeing or whoever...) b) The Apollo program actually cost not just money, but human lives = a much worse outcome than just losing a test rocket. And Apollo 13 crew was very lucky to have returned to Earth alive. c) Losses of test hardware can only really be somewhat prevented by being extremely careful and pedantic during development, which takes time, and guess what? More time spent obsessing about every single detail = more money spent on development. It is entirely possible that the "hardware is expendable" approach is much cheaper than what you would like to have.
- cratermoon 3y ago
  If a test flight doesn't achieve the testing objectives, that's a failure. No one would argue that failing to find a bug before putting software in production was a testing success just because all the tests executed without errors.
  - ceejayoz 3y ago
    > If a test flight doesn't achieve the testing objectives, that's a failure. Demonstrably incorrect. Examples: https://www.youtube.com/watch?v=AqeJzItldSQ https://www.youtube.com/watch?v=AqeJzItldSQ is a Saturn launch abort test that failed. It failed in a way that they were able to determine that intended test would have worked, though. 1:20 for the meat of things. https://en.wikipedia.org/wiki/Apollo_6 https://en.wikipedia.org/wiki/Apollo_6 also failed to achieve its objectives; "Despite the engine failures, the flight provided NASA with enough confidence to use the Saturn V for crewed launches; a potential third uncrewed flight was cancelled." All that aside, SpaceX was quite clear that the latest Starship test had multiple objectives, and that "successfully splashdown near Hawaii" was deemed quite unlikely. It successfully demonstrated a number of items, including fairly critically the launchpad changes. It wasn't one test; it was a bunch of tests in one flight.
  - gpm 3y ago
    There are multiple categories of objectives... Objectives that motivated the test flight. Objectives that are expected to succeed. Objectives that you threw on because "if the $xx million object is still intact it would be nice to get some useful data, and the FAA wants a complete flight plan anyways". If that last category doesn't succeed that doesn't mean the test flight was a "failure" from the businesses perspective. They still got what they wanted, they just didn't get the icing on top. The test flight that destroyed the pad is properly categorized as a failure. The flight termination system was expected to work. They expected not to cause that much damage to their infrastructure and surroundings, their relationship with the FAA, their ability to get licenses, etc. To argue that it wasn't a failure, you have to argue that the flight termination system was in the category of systems where a failure was considered acceptable. If that was the case, everyone involved in launching that flight ought to to go jail for recklessly endangering the public. The most recent test flight though seems to have been a pretty resounding success. Everything that they said they really wanted to see happen, happened. Yes, both stages had failures in "we might not even get here" test objectives after that. That's ok.
stoneman24 3y ago
If I remember correctly there has been a couple of falcon failures, it should be noted that the starship project is is still well in the development phase. The success criteria for integrated launch test 1 was to clear the launch pad (which it nearly destroyed) test 2 was get past the stage seperation, which it did. Spacex have a very fast cadence for tests and seem not to make the same error twice. The best test environment is really trying to fly the ship.

me_me_me 3y ago

[flagged]

pixl97 3y ago
How is that exactly? Launch one really was a comedy of errors in the launch platform. In launch 2 the booster did exactly what every other booster by everyone else (except the falcon 9) does. Got it's payload to the target altitude before separation. The second stage reached space. The N1 platform didn't do any of that. You have no idea what a testing platform looks like, and are too used to NASA one shot rockets that cost 3 billion each just to make sure nothing goes wrong.
- simiones 3y ago
  The booster exploded after separation, which is never a good sign. Normal boosters for modern rockets don't do that. The second stage exploded as well, possibly because of FTS, possibly not (was it ever confirmed?).
  - jdminhbg 3y ago
    > The booster exploded after separation, which is never a good sign. Normal boosters for modern rockets don't do that. It exploded while attempting to test its landing maneuver. If it just turned off the engines and dropped itself into the ocean like a normal booster, it likely would not have exploded (for one thing, there wouldn't be any fuel left in it being saved for landing).
  - ggreer 3y ago
    Well it's not a normal booster. It's a test booster. Also normal boosters don't do a flip while getting blasted with rocket exhaust. SpaceX clearly has a winning method, as they have a success rate of 99.3% and hold the record for most consecutive successful launches at 253. Second place is Soyuz-U, which had 112 consecutive successful launches and an overall success rate of 97.3%. SpaceX has more consecutive successful booster landings (173) than any space program has had successful launches.
  - 3y ago

rodlette 3y ago

I know nothing about rockets but bits of project management: it's common to break down projects into smaller parts and derisk designs/implementations by testing each piece. The refueling team might be ready to test, even though the "don't explode" team are still working on it.

colechristensen 3y ago

This is roughly equivalent to watching a developer work and insulting them when their code doesn’t compile. Nobody who writes code cares, that’s just what writing code is like. You could spend a ton more time writing code trying to get it to compile without errors ever, but that would be a whole lot more pointless work.

Kapura 3y ago
Writing software and building rockets are unlike each other in many respects; the cost of small errors being high among them.
- nomel 3y ago
  > the cost of small errors being high among them There are some great documentaries about the NASA team that does safety critical software: https://www.youtube.com/watch?v=iJNNJxC12UM https://www.youtube.com/watch?v=iJNNJxC12UM
- marcusverus 3y ago
  There are costs and then there are trade-off costs. In the long run, the trade-off costs of slow-moving perfectionism are FAR higher than the cost of the ‘fail fast and early’ culture at SpaceX.