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posted by takyon on Saturday January 12 2019, @10:11PM   Printer-friendly
from the fired-into-space dept.

SpaceX to lay off 10% of its Workforce:

SpaceX, citing a need to get "leaner," said Friday it will lay off more than 10% of its roughly 6,000 employees.

[...] "To continue delivering for our customers and to succeed in developing interplanetary spacecraft and a global space-based internet, SpaceX must become a leaner company," the Hawthorne-based company said in a statement. "Either of these developments, even when attempted separately, have bankrupted other organizations. This means we must part ways with some talented and hardworking members of our team."

[...] SpaceX makes most of its money from commercial and national security satellite launches, as well as two NASA contracts, one a multibillion-dollar deal to deliver cargo to the International Space Station and the other up to $2.6 billion to develop a capsule that will deliver astronauts to the space station. The first launch of that capsule, without a crew, is planned for February.

The Elon Musk-led company has even more ambitious — and expensive — plans. Musk has said SpaceX will conduct a "hopper test" of its Mars spaceship prototype as early as next month. The production version of that spaceship and its rocket system is expected to cost billions.

Earlier this month, privately held SpaceX said it raised about $273 million in equity and other securities in an offering that sought to raise about $500 million, according to a filing with the Securities and Exchange Commission. The company is worth $31 billion, according to Equidate, which tracks private-company valuations.

In May, Shotwell told CNBC that the company is profitable and has had "many years" of profitability.

There's an old adage about making something: "Good. Fast. Cheap. Pick two." Is SpaceX trying to pick all three?

Related: SpaceX CEO Elon Musk Fired Managers and Employees in June to Shake Up Starlink Project
Elon Musk's SpaceX Is Raising $500 Million in Funding; Now Valued at $30.5 Billion


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  • (Score: 1) by Ethanol-fueled on Sunday January 13 2019, @03:48AM (10 children)

    by Ethanol-fueled (2792) on Sunday January 13 2019, @03:48AM (#785782) Homepage

    I do not believe that. To deal with the serious heat upon reentry is to use tiles with a chemical composition of a ceramic nature. Steel is strong but conducts heat like a motherfucker.

  • (Score: 3, Informative) by takyon on Sunday January 13 2019, @04:04AM

    by takyon (881) <reversethis-{gro ... s} {ta} {noykat}> on Sunday January 13 2019, @04:04AM (#785784) Journal

    Yes, conducting heat is part of the plan:

    https://arstechnica.com/science/2019/01/elon-musk-is-really-really-excited-about-his-starship/ [arstechnica.com]

    • The vehicle's exterior will be made from a stainless-steel alloy that will not buckle and will remain stable on the launchpad even when unpressurized. The strength and weight of "full hard stainless" at cold temperatures is slightly better than carbon fiber, at room temperature it is worse, and at high temperature it is vastly better.
    • The metallic skin of Starship will get too hot for paint, so it will have a stainless mirror finish. It will need much less shielding as a result, and areas that take the brunt of atmospheric entry heating will be activity cooled with residual liquid methane. As a result, "Starship will look like liquid silver."
    --
    [SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
  • (Score: 2) by Immerman on Sunday January 13 2019, @04:16AM (3 children)

    by Immerman (3985) on Sunday January 13 2019, @04:16AM (#785785)

    Actually stainless steel specifically is a pretty lousy thermal conductor, at least as metals go. It's also non-magnetic, which isn't related (so far as I know), but took me by surprise when I learned it.

    Of course, heating stainless steel too much - say like with a raging wood fire venting through stainless steel stovepipe, and it rapidly reverts to normal magnetic, rust-prone steel. I'm sure reentry would do the job too, even if you're only dealing with the (relatively) much cooler air directly adjacent to the skin. (Most of the heat is concentrated in the compressive shockwave a short distance in front of the reentering craft, and a mirror finish should reflect that away pretty well, rather than absorbing most of it the way blackened tile would)

    A likely missing piece, that I've only heard mentioned a couple times, is that Musk is supposed to be looking at active cooling during rentry, rather than relying on exotic, fragile high-temperature thermal insulation. One of the problems with all that fancy thermal insulation, in addition to the price, is that it can mostly be broken with your bare hands, and if even a small piece is broken off then the intense heat can potentially burn its way through whatever is underneath.

    Of course, it's also possible that the whole thing is a bit of misdirection, and it's actually only the Starhopper that will be stainless steel.

    • (Score: 2) by crafoo on Sunday January 13 2019, @10:24AM (1 child)

      by crafoo (6639) on Sunday January 13 2019, @10:24AM (#785852)

      some stainless alloys are mildly ferromagnetic (usually low grade?). your standard 304 alloy is not though. The stuff that is ferromagnetic also tends to corrode much easier. Generally there are many flavors of stainless. The arrangement of the crystalline structure can give it weak magnetic properties; from the particular alloy it is or (I think) via some types of heat treatments. The skin surface can also be passivated changing it's corrosive properties, but I don't believe that effects it's magnetic properties.

    • (Score: 0) by Anonymous Coward on Monday January 14 2019, @03:41AM

      by Anonymous Coward on Monday January 14 2019, @03:41AM (#786248)

      > active cooling during rentry

      This was a feature of the Dyna-Soar spaceplane (USAF funded), from the late 1950s. It's a fairly amazing story, here's a recent look back,
      https://www.defensemedianetwork.com/stories/what-might-have-been-x-20-dyna-soar/ [defensemedianetwork.com]

  • (Score: 2) by bob_super on Sunday January 13 2019, @09:06AM (4 children)

    by bob_super (1357) on Sunday January 13 2019, @09:06AM (#785839)

    They deal with the worst of the heat by turning on the engines.
    That creates a kind of air shield which prevents the excessive direct air hypersonic friction that requires the ceramic tiles. That's also how they can come in with the blunt end first without re-enacting Columbia.

    Now, they still turn off the engines above mach 3 or 4, but that's stuff that Concorde, missiles, and other supersonic toys can handle with proper metal, without a dedicated brittle and heavy shield.

    • (Score: 2) by Immerman on Sunday January 13 2019, @04:54PM (2 children)

      by Immerman (3985) on Sunday January 13 2019, @04:54PM (#785932)

      You're thinking of the boosters I think, which only has to deal with a fraction of orbital velocity (less than a third), not a reentry vehicle, which is what Starship will be. Coming from orbit you're doing about mach 23, hitting the air broadside like a brick to keep the superheated plasma shockwave in front of you as far away from your vehicle as possible, and doing your best to avoid laminar flow that would heat the back side of your vehicle as well. By the time you're down to mach 3 or 4, all the hard work has already been done.

      • (Score: 2) by bob_super on Monday January 14 2019, @05:22PM (1 child)

        by bob_super (1357) on Monday January 14 2019, @05:22PM (#786500)

        I just verified on the last launch video: That first-stage entry/shield burn happened at 4500km/h (Mach 4 at ground level).

        I have not read anything anywhere suggesting that SpaceX is planning for Spaceship to re-enter in a different way, even if the speed will definitely make it quite different. The highly conductive steel and lack of tiles suggests they're planning to scale what works.

        I'll wait for Ars's Statistical to provide answers, as usual.

        • (Score: 2) by Immerman on Monday January 14 2019, @10:56PM

          by Immerman (3985) on Monday January 14 2019, @10:56PM (#786683)

          Mach 4 is practically standing still in comparison - mach 24 (24,000km/h) involves 36x the kinetic energy in the approaching air molecules - you can't "just do what works" at low speed, because it simply doesn't work in with that much of a difference. And of course you're no longer dealing with air - you're dealing with plasma.

          As I mentioned, you *really* don't want that plasma to touch your spacecraft. And it's pretty much impossible to prevent that when you're shoving a long, thin vehicle through the air. That's why the Space Shuttle belly-flops during reentry instead of trying to fly - go nose-first and the laminar flow would reattach to the back end of the shuttle and quickly vaporize it. Even the heat shield isn't designed for direct contact with reentry plasma.

          The boosters only have to deal with heating from air friction - which is only a tiny fraction of the heat during reentry, where the vast majority comes from the plasma shockwave. Mach 4 has no such problem.

          The appropriate comparison would be to it's current reentry vehicles - the Dragons. All of which have nice thick heat shields that they use to avoid being vaporized by the plasma they create as they belly-flop into the atmosphere.

          All the SpaceX animations I've seen show Starship coming in broadside until its slowed down to below hypersonic speeds. The whole point of the mobile "wings/fins" is to stabilize that maneuver - they're not actually wings, fins, or any other sort of normal aerodynamic surface, as he has stated several times.

          Musk is probably talking about dumping the heat shield because

          1: Those things are *expensive*, fragile, and don't last all that long even under the best of conditions. Especially when you're talking about covering half a fair-sized grain silo, which then needs to be completely inspected before every flight, since even a small crack could mean a rapid unscheduled disassembly.
          2: They pretty much have to be black to radiate heat fast enough - but that means they also absorb pretty much all the heat coming at them from the plasma shockwave.
          3: A mirrored surface would instead reflect the heat from the plasma heat - thus eliminating the need to deal with the vast majority of reentry heat, and leaving only air friction
          4: Active cooling is completely adequate to the task of shedding the heat from air friction. It's even been considered for shedding the full heat of reentry, as in the Dyna-Soar mentioned in another comment.

    • (Score: 2) by Immerman on Sunday January 13 2019, @05:00PM

      by Immerman (3985) on Sunday January 13 2019, @05:00PM (#785934)

      Meant to also mention that friction is only responsible for a tiny percentage of the heating for reentry - the vast majority of the heat is coming from that plasma shockwave, which never touches the vehicle itself except via thermal radiation thanks to a cushion of much lower temperature compressed air that forms between them. Which is why you reenter broadside - an aerodynamic profile will bring let that plasma flow right up against the vehicle, and then even those expensive ceramic tiles wont be enough to protect you.