13 votes

Inside SpinLaunch, the space industry’s best kept secret

9 comments

  1. [3]
    emdash
    Link
    This is totally not going to work. As covered in the thread posted by @asoftbird, any gains in performance are going to be immediately offset by the additional mass you need to add to structurally...

    This is totally not going to work. As covered in the thread posted by @asoftbird, any gains in performance are going to be immediately offset by the additional mass you need to add to structurally enhance the vehicle (and payload!) against the incredible acceleration and thermodynamics that the rocket will need to deal with after ejection.

    All the while, SpaceX, Blue Origin, Rocket Lab, and all the other companies practicing "traditional" launch are iterating, improving, and optimising, to the point where any gains from SpinLaunch's technique will be rendered moot—even while they have to deal with the tyranny of the rocket equation and the terrible performance one gets from chemical propulsion. This reminds me of a quote from John Gall:

    A complex system that works is invariably found to have evolved from a simple system that worked. A complex system designed from scratch never works and cannot be patched up to make it work. You have to start over, beginning with a working simple system.

    This is complex. In comparison, traditional rocket launch is simple. If SpinLaunch were a publicly traded company, I would be the first to short them.

    8 votes
    1. [2]
      KapteinB
      Link Parent
      Well... According to the article, 10.000 G doesn't seem to be much of an issue for the payload. Yeah, that surprised me as well. I have no idea if a propulsion system can handle those forces...

      As covered in the thread posted by @asoftbird, any gains in performance are going to be immediately offset by the additional mass you need to add to structurally enhance the vehicle (and payload!) against the incredible acceleration

      Well...

      Over the next few years, the team ran hundreds of high-speed tests. Most of them were to study and improve the system, but some were to mollify skeptical investors and potential customers who didn’t believe a payload could withstand the extreme forces. The team sent solar cells, radio systems, telescope lenses, batteries, GPS modules, and control computers whirling at high speeds; they all survived with little to no damage. In one test, Yaney attached an iPhone to the tether and spun it up until it experienced forces 10,000 times stronger than gravity. Afterward, he used the phone to FaceTime a colleague.

      According to the article, 10.000 G doesn't seem to be much of an issue for the payload. Yeah, that surprised me as well. I have no idea if a propulsion system can handle those forces though.

      and thermodynamics that the rocket will need to deal with after ejection.

      That's my personal biggest worry; ejecting an object from vacuum to 1 atmosphere of pressure at incredible speeds in an instant, that doesn't sound like it's going to end well. What if we placed the centrifuge at the top of a mountain though? Lower air pressure means less thermodynamics to worry about, and shorter distance to orbit means a lower launch speed is required.

      companies practicing "traditional" launch are iterating, improving, and optimising, to the point where any gains from SpinLaunch's technique will be rendered moot

      I think there's definitely some merit to electrifying the first stage of a rocket launch, but I'm not sure a centrifuge is a good solution. The advantage of a centrifuge in this case is that they give a high speed compared to the size of the facility, but maybe it would be better to instead construct a kilometre long rail gun up the slope of a mountain, for a more gradual (and single-directional) acceleration.

      2 votes
      1. guy
        Link Parent
        That will be a requirement, I'd think. The one time, upfront cost of purchasing land at the highest elevation possible would payoff on every launch. You're skipping the thickest part of the...

        What if we placed the centrifuge at the top of a mountain though?

        That will be a requirement, I'd think. The one time, upfront cost of purchasing land at the highest elevation possible would payoff on every launch. You're skipping the thickest part of the atmosphere for free.

        1 vote
  2. [3]
    asoftbird
    Link
    A twitter thread on feasibility: https://twitter.com/chmn_victor/status/1223923307847831558?s=21
    5 votes
    1. [2]
      tlalexander
      Link Parent
      Interesting comment at the end that it could work on the moon. The company is likely to go bankrupt+ before we’d need such a thing on the moon, but it’s good to know it would work theoretically....

      Interesting comment at the end that it could work on the moon. The company is likely to go bankrupt+ before we’d need such a thing on the moon, but it’s good to know it would work theoretically.

      +Assuming they don’t get it working and find success for Earth based launches. But the twitter thread says it may be possible for them to succeed!

      2 votes
      1. sqew
        Link Parent
        It'll definitely be interesting to see something like this on the Moon or Mars as an enabler for orbital industry. Something like converting metal oxides in lunar regolith into slugs of pure...

        It'll definitely be interesting to see something like this on the Moon or Mars as an enabler for orbital industry.
        Something like converting metal oxides in lunar regolith into slugs of pure metals and launching them into low lunar orbit.

        Just gotta hope that the lunar settlements don't get mad at Earth and start chucking rocks down the gravity well...

        3 votes
  3. [3]
    KapteinB
    Link
    @mycketforvirrad: Thanks for moving this post. I somehow forgot we have a ~space group.

    @mycketforvirrad: Thanks for moving this post. I somehow forgot we have a ~space group.

    3 votes
    1. [2]
      mycketforvirrad
      Link Parent
      No worries! I'm keeping an avid eye out for your next Melodi Grand Prix post, by the way.

      No worries! I'm keeping an avid eye out for your next Melodi Grand Prix post, by the way.

      1 vote
      1. KapteinB
        (edited )
        Link Parent
        I'm working on it now. :-) I've been travelling this weekend, visiting family, so I didn't even have time to watch Saturday's show until tonight. edit: typo

        I'm working on it now. :-) I've been travelling this weekend, visiting family, so I didn't even have time to watch Saturday's show until tonight.

        edit: typo

        2 votes