back to article Musk shows off the latest power plant for Starship, replaces Tesla CFO with a millennial

SpaceX supremo Elon Musk has announced that the company is about to fire up the latest iteration of the engine destined for its huge boosters. Musk helpfully included an image of the power plant with a human in the background to give an idea of size. Preparing to fire the Starship Raptor engine at @SpaceX Texas pic.twitter. …

  1. Robert Sneddon

    Methane?

    The Raptor engine is/was supposed to be liquid methane/liquid oxygen rather than LOX/RP (kerosene) like the Falcon engines. Is there any mention whether the test and final launch version of these engines will move to this new fuel?

    Comparison of the Raptor to the MIGHTY F1!!! is not a good one -- the F1 was a dog, engineering-wise, very low efficiency and rather crude. The better rocket engine of the time was the Soviet RD-170 which was more efficient, produced more thrust and could be throttled and gimballed in flight. Cut-down versions of the RD-170 still fly today, even powering American launchers such as the Atlas V which uses the twin-nozzle RD-180.

    1. CliveS
      Mushroom

      Re: Methane?

      Last thing I saw they were still going with Methane/LOx, with chamber pressure of a terrifying 300 bar and pre-burner (for turbo-pump) running at 810 bar!!

    2. Anonymous Coward
      Anonymous Coward

      Re: Methane?

      the F1 was a dog, engineering-wise, very low efficiency and rather crude. The better rocket engine of the time was the Soviet RD-170 which was more efficient, produced more thrust and could be throttled and gimballed in flight.

      Neat. And what exactly did the Soviets accomplish with it? Took their pencils to orbit, did they?

      1. Gene Cash Silver badge

        Re: Methane?

        However, the RD-170 never flew.

        Interestingly enough, it shares the same exotic full-flow staged-combustion cycle that the Raptor has.

        The F1 was kind of a dog because we were in a hurry, and also breaking new ground. A lot of the engine was an educated guess.

        1. Anonymous Coward
          Anonymous Coward

          Re: Methane?

          "However, the RD-170 never flew."

          I think you'll find it did:

          <http://www.russianspaceweb.com/rd170.html>

          "The engine was first used on the Zenit rocket in 1985 and then on Energia in 1987. On Dec. 5, 2013, NPO Energomash conducted 1000th firing of the RD-171M engine at the company's test bench, NIK-751."

          But not before:

          "One of the botched tests at NPO Energomash test facility on the outskirts of Moscow reportedly ended with a massive explosion that sent a heavy metal cover of the troubled engine's turbopump several miles away concluding with an impact on the runway of Moscow's main international airport in Sheremetievo!"

          The RS-25 Space Shuttle Main Engine also used a staged combustion cycle.

          btw "The F1 was kind of a dog because we were in a hurry, and also breaking new ground. A lot of the engine was an educated guess."

          When they started designing the future big engine back in 1955 (which eventually led to the F1), yes it was a lot of educated guesswork about what would work. And a lot of the educated guesses were wrong, hence all the big explosions and other development problems. But they solved those problems and ended up with a rocket engine that worked reliably and developed a specific impulse of only about 10% less than the 20-odd year younger RD-170 which uses staged combustion so ought to be better. Don't diss the F1: they did well on that design, they really did. Yes of course more recent designs are better: that's engineering progress for you.

      2. Phlogistan

        Re: Methane?

        There was and is absolutely nothing wrong with the concept of the Big Dumb Booster.

        They are a straightforward engineering way to get *LOTS* of mass into space in a useful way in ONE GO. Often relatively cheaply. O2/H2 plumbing is seldom simple and never cheap.

        The Sea Dragon conceptualized in 1962 could have been built with then current technology and gotten a huge amount of useful stuff into orbit. Sometimes bending LOTS of tin quickly to get your job done is not considered bad.

        The reusability case that Elon Musk brought to fruition was *ALWAYS* the goal of a true space-faring society but actually getting stuff into space is pretty much the only goal we measure by.

        There are still use cases for expendables now. IF they are cheap and/or plentiful and can actually do the job you need done *now*. Re: Rocket Lab Electron

        Launch often. Break things. Iterate. Improve.

        Per Aspera Ad Astra.

      3. Spamfast
        Alien

        Re: Methane?

        Neat. And what exactly did the Soviets accomplish with it? Took their pencils to orbit, did they?

        Not this old chestnut again. Both the US & Soviets used pencils early on but stopped the practice due to flamability in high oxygen atmosphere and the obvious risk of conductive graphite debris getting into electronics and elsewhere.

        Both space agencies ended up buying the pens developed by Fisher Pens using no more than $1 million of the company's own money - NASA paid no part of the development costs. Once they'd confirmed it was fit for purpose NASA paid around three dollars per pen for the first batch of a few hundred. Occassionally, government projects do get value for money from private companies!

        See Snopes for information about the Fisher Pen.

    3. choleric

      Re: Methane?

      Yes it's understood to be methane and oxygen. Interesting feature of this engine that's causing some chatter is the way the curvature of the exhaust bell varies along it. Seems they may be experimenting with a method of allowing efficient deep throttling.

    4. Anonymous Coward
      Anonymous Coward

      Re: Methane?

      "F1 was a dog, engineering-wise, very low efficiency and rather crude. The better rocket engine of the time was the Soviet RD-170 which was more efficient, produced more thrust and could be throttled and gimballed in flight"

      Referring to my copy of the Saturn V Haynes manual:

      The "big engine" development programme which lead to the F1 began in 1955. NASA issued the contract for the actual F1 engine in 1959, with first delivery to NASA in 1963 and first flight in 1967. Also, four out of the five F1s fitted to each Saturn V first stage were gimballed for steering the rocket.

      <http://www.russianspaceweb.com/rd170.html> says that the RD-170 development programme began in 1976 with first flight in 1985. That makes it roughly twenty years younger.

      Is it really sensible to consider these two engines as contemporaries?

      The RD-170 didn't fly until 1985, so could perhaps be better compared to the RS-25 Space Shuttle Main Engine (first flight 1981) which was also a highly sophisticated and reliable bit of kit - and with a better specific impulse than the RD-170 and derivatives. The RS-25 could be throttled and gimballed too. Here are the efficiency figures:

      F1 Isp (vac.): 2.98 km/s (304 s)

      RD-170 Isp (vac.): 3.30 km/s (337 s)

      RS-25 Isp (vac.): 4.44 km/s (452 s)

      Putting the RS-25 on the list is something of an unfair comparison because while the RD-170 develops a superb specific impulse for a kerosene fuelled engine, the RS-25 has the huge efficiency advantage of using hydrogen as fuel.

      But the F1 wasn't bad for a gas generator cycle RP1/LOX engine: it's only about 10% down on the much later and more sophisticated RD-170 - which ought to have the higher Isp due to using a staged combustion cycle.

      All things considered, I think it's a bit unfair to call the F1 engine a "dog" and rather crude.

      Yes, it wasn't hugely efficient but that's mostly due to the RP1/oxygen propellant mix as much as anything else. And they used that mix in part to keep the size of the main fuel tanks down: trying to build a hydrogen fuel tank system which could hold enough to do the job of an Apollo launch rocket first stage would probably have been beyond what was feasible at the time. It's the same thinking behind using the same fuel for the RD-170.

      What the Saturn V first stage had to do was impart a huge amount of impulse to the upper stages, and that meant enormously powerful engines and enormous amounts of energy in the fuel tanks.

      So the relatively low efficiency compared to a hydrogen fuelled engine was the result of a sensible engineering compromise: accept lower efficiency and get a smaller rocket stage overall which didn't have to deal with the problems of just how make the stage big enough to carry enough low-density liquid hydrogen to provide the required total impulse, then keep the stuff liquid for long enough, and then pump it - engineering issues which caused big problems on the Saturn V upper stages. Both the F1 and the hydrogen fulled upper stage engines used their rocket fuel as a turbo-pump lubricant and guess what? It was easier to get that to work using RP1 as the lubricant/propellent than it was with liquid hydrogen.

      The early F1s blew up in testing. The early hydrogen fuelled engines melted their injector plates. They all had design problems which needed solving. Trying to get a hydrogen fuelled engine of the power of the F1 working on time and in budget would have been exceptionally hard: you'd've been up against all the problems the F1 design encountered plus the additional problems of liquid hydrogen.

      I suspect that if you were to look carefully at the design details, you'd find that the F1 engine was probably the most sophisticated operational RP1/liquid oxygen rocket engine of its era. It had to be sophisticated, or it wouldn't have provided the required performance while working reliably. If you want to find out more, try getting a copy of the Haynes manual for the Saturn V rocket: the things really are quite remarkable.

      That book's got a lot of detail. For example: the F1's main thrust chamber was made from tubes: 89 pipes took 70% of the RP1 propellant downwards, 89 brought it upwards: for thrust chamber cooling. Part-way down the nozzle, the pipes were bifurcated so there were 178 down tubes and 178 up tubes. This whole assembly was brazed together as a single unit in a single operation in a large retort. Is that crude, or is it well developed and appropriate engineering?

      Yes, of course more modern rocket engines like the RD-170 and descendants are better but that's kind of the point of engineering: things get better in the future as more things are learnt, better materials are developed, design techniques are improved, and so on.

      1. Mark 85 Silver badge

        Re: Methane?

        Well said AC. Comparisons of this sort in many ways is like comparing the early jet fighter engines with the latest ones.

      2. Big John Silver badge

        Re: Methane?

        Comments like this one are why I come to ElReg. :)

  2. Anonymous Coward
    Anonymous Coward

    millennial

    oh it's so UNFAIR i have to work. everything is so unfair. I don't like my office. the windows are too big, its too cold. its too hot. the lift is too slow. the coffee is too expensive. SO UNFAIR.

    1. Anonymous Coward
      Anonymous Coward

      Re: millennial

      Right, because no Boomer or GenX'er has ever complained about anything.

      Nope, it was all sunshine and happiness until those damn Millennials spontaneously came into existence in the early 1980s.

  3. Anonymous Coward
    Anonymous Coward

    Pedantry: thrust units.

    The article mentioned that "Musk also reiterated the 200 metric tons (440,925 lbf) thrust".

    Yes, Musk did refer to 200 metric tons of thrust. But metric tons are a unit of mass, not force. What he probably meant was 1.962 kN thrust - which comes out here as 441,075 lbf for those who still think that way.

    1. Anonymous Coward
      Anonymous Coward

      Re: Pedantry: thrust units.

      I think you mean 19619 Norris.

      1. Robert Helpmann?? Silver badge
        Boffin

        Re: Pedantry: thrust units.

        I think you mean 19619 Norris.

        That's right on a number of levels. I hear Musk's next project will be cloning Chuck Norris and then having the clones all stand in a carefully calculated formation from which they can simultaneously punch an enormous rocket into space. That could definitely work!

    2. Muscleguy Silver badge

      Re: Pedantry: thrust units.

      Except if it is weight instead of mass then g which is in m/s/2 so an acceleration counts. You have to imagine the engine is pushing against a giant, heavily resistant scales which is deflected so measuring the weight of the thrust. Much like the bathroom scales do due to your weight.

      Your confusion is to forget that the measure in question means BOTH mass and weight. You assumed the first when the second is obviously in play.

      1. Anonymous Coward
        Anonymous Coward

        Re: Pedantry: thrust units.

        "Your confusion is to forget that the measure in question means BOTH mass and weight. You assumed the first when the second is obviously in play."

        The reason I could work out Musk meant 1,962 kN thrust when he said 200 metric tons is that I'm perfectly well aware of HIS confusion.

        However, there is no question at all that 1 kg is a formally defined scientific unit of mass, and that a metric ton is defined as 1000 kg and is therefore a measure solely of mass and not weight or force.

        <https://www.bipm.org/en/publications/si-brochure/kilogram.html>

        <https://www.bipm.org/utils/common/pdf/si_brochure_8_en.pdf> "Table 3. Coherent derived units in the SI with special names and symbols" defines the SI unit of force as the newton, expressed in terms of SI base units as m kg s^−2 (which could equally be written kg m s^-2).

        And weight is the force exerted by a mass in a particular gravitational field (quibbling aside). They are different quantities entirely.

        So the weight of 200 metric tons at one standard Earth gravity is 200,000 kg * 9.81 m s^-2, which is 1,962,000 kg m s^-2, aka 1,962 kN - a force, not a mass.

        Colloquially speaking and sat here on Earth, if someone wants to talk about metric tons thrust, it's not such a big deal: we can all work out what's meant easily enough. But it's no way to think if you're actually doing rocket engineering.

        I mean, look: if Musk ever manages to land one of his Starship rockets on the Moon (surface gravity 1.62 m s^-2), he won't suddenly find that the 200 metric ton thrust specification he just gave means that his rocket's been downgraded to 200,000 kg * 1.62 m s^-2 = 324 kN thrust just because 200 metric tons mass weighs less on the Moon.

        P.S. The reason I typed 1.962 kN when I meant 1,962 kN in my initial post is because I'm a twerp.

  4. rcxb

    What's with the dig at millennials? You know they're just shy of middle-age now, right? Seems reporters think "millennial" perpetually means early-20s young adults. In fact there's never been a more clearly delineated generation, with the date right in the name. Might as well call out those no-good young whipper-snapper GenX'ers.

    1. Adrian 4 Silver badge

      Is millenial that clearly defined ?

      Does it mean 'born in 2000' ? Or 2001 ? Or after 2000 ? Or under 18 in 2000 ?

      Or 'younger than me' ?

      1. Cuddles Silver badge

        "Is millenial that clearly defined ?"

        Fairly clearly, yes. It refers to the generation that came of age around the turn of the millennium, specifically the term was coined to refer to those who would graduate high school in 2000. It generally covers birth dates of around 1980-1995, although sometimes it can include the late '70s and as late as 2000. It's very specifically not "born in or after 2000", despite that being an oddly common misconception.

  5. DJV Silver badge

    Bungee CFO!

    Scott Adams got there first!

    https://dilbert.com/strip/1994-09-07

  6. Phage

    "However, with less than two months as VP of Finance under his belt before his elevation to Tesla CFO, he has a worrying lack of experience." You win Understatement of the Month.

    As someone in a similar role I can tell you that appointing someone this inexperienced is often a red flag for potential fraud.

    1. Killing Time

      'As someone in a similar role I can tell you that appointing someone this inexperienced is often a red flag for potential fraud.'

      While I'm impressed with the level of comentards El Reg attracts these days I don't see that a lack of direct experience is necessarily a red flag. It does depend on the integrity of the personality.

      It could equally be said that the greater the experience the more the likelihood of knowing the systemic weaknesses which lead to fraud.

      Theoretically that is what oversight and audit are there to eliminate. If that is in place, risk of fraud shouldn't be unduly elevated.

    2. Spazturtle Silver badge

      Their previous CFO (the one before Deepak) quiting after a month on the job wasn't a big enough red flag?

  7. Voyna i Mor Silver badge

    MBA

    Musk is right his CFO doesn't need it.

    Degrees in psychology and forensic accountancy might be far more useful.

    1. Tom 7 Silver badge

      Re: MBA

      An MBA is like a logic lobotomy. I've even had friends take them and they can no longer do simple things. Making a cup of tea involves several meetings,

  8. whitepines Bronze badge
    Unhappy

    "The demand for Model 3 is insanely high. The inhibitor is affordability. It's just like people literally don't have the money to buy the car,

    Ummm....I've got the money for the car. And I'm not going to buy one. I have no interest in a rented platform running proprietary software that answers back to its masters at Tesla, probably spies on everything said in and around it, mines my driving patterns for saleable data, locks me out of any maintenance or modifications I might want to do, and requires a giant EULA before purchase to (sort of) make this steaming hot pile of crap semi-legal.

    And I'm expected to pay more for this abuse. No thanks!

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