16 votes

A space startup that wants to throw rockets into space

27 comments

  1. [7]
    nothis
    (edited )
    Link
    That's awesome! Interesting that they're planning to launch at a 35° angle, which is the ideal throw angle after considering air drag, like that is what javelin throwers use. EDIT: I am also...

    That's awesome! Interesting that they're planning to launch at a 35° angle, which is the ideal throw angle after considering air drag, like that is what javelin throwers use.

    EDIT: I am also noticing Tildes has now officially 3 posts with the "centrifugal launch accelerators" tag.

    5 votes
    1. [6]
      vektor
      Link Parent
      Now that you mention it, I find it interesting that they limit the angle at all. Surely it would be an almost negligible extra cost to make sure you can launch at any angle you want. I mean, you...

      Now that you mention it, I find it interesting that they limit the angle at all. Surely it would be an almost negligible extra cost to make sure you can launch at any angle you want. I mean, you could set up the centrifuge disk vertically and have the chute movable (i.e. rotating around the perimeter), that way you can launch at any angle. Instead, they lay the disk on its side and fix the chute in place.

      I mean, they probably did the math here and had to have tight restrictions on what you can do. With the engineering effort that is the centrifuge, I don't think they have the margins to throw a smaller payload at a faster velocity, which kind of eliminates the possibility of going for a higher orbit. So that way, you just go for what works for LEO and stick with it.

      2 votes
      1. [2]
        mtset
        Link Parent
        At the very least, it would require a gigantic biaxial hydraulic system, which would be yet more complexity for the launch system, and would likely fail more often than that actual centrifugal...

        Surely it would be an almost negligible extra cost to make sure you can launch at any angle you want.

        At the very least, it would require a gigantic biaxial hydraulic system, which would be yet more complexity for the launch system, and would likely fail more often than that actual centrifugal accelerator. I think they might do this in the future, but the benefits are pretty minimal for now; most of their customers will want equitorial LEO.

        2 votes
        1. vektor
          Link Parent
          What I had in mind, you don't have to move the centrifuge at all. Just the chute needs to rotate around the circumference. Or, realistically, you could just build a few at interesting angles and...

          What I had in mind, you don't have to move the centrifuge at all. Just the chute needs to rotate around the circumference. Or, realistically, you could just build a few at interesting angles and have them all be static. This doesn't give you complete 2d control over elevation and azimuth, just elevation. But if you could make different launch velocities work, this would be interesting.

          Also: unless you build this at the equator, equatorial LEO isn't feasible.

          3 votes
      2. [3]
        Eric_the_Cerise
        Link Parent
        IDK why that is the perfect angle, but I'm sure there are exactly 0 other "interesting" angles to launch from this way. My nutshell guess is ... lower doesn't clear the atmosphere enough (or,...

        IDK why that is the perfect angle, but I'm sure there are exactly 0 other "interesting" angles to launch from this way. My nutshell guess is ... lower doesn't clear the atmosphere enough (or, possibly, fast enough), while higher wastes energy that could go towards reaching orbital velocity.

        Very similarly, though, I would expect they want to be able to launch in different directions. Once something is in orbit, changing direction to get to a different orbit is just ridiculously expensive, fuel-wise. It's always better to throw your rocket in the correct general direction of your desired final orbit ... and in that case, there definitely are many different "interesting" orbital directions.

        Being able to point the launch chute the way you describe would definitely be helpful in that regard.

        1 vote
        1. [2]
          vektor
          (edited )
          Link Parent
          I don't think your proposal would work: To be able to aim to different azimuths at the same ideal elevation, that is not a proper circle, so you'd have to move the centrifuge itself, which is...

          I don't think your proposal would work: To be able to aim to different azimuths at the same ideal elevation, that is not a proper circle, so you'd have to move the centrifuge itself, which is going to be nigh-on impossible, what with it being super big.

          (E: That said, if you combine picking the right launch window with a fixed-angle centrifugal plane and different ejection angles, you can span quite the large area of possible orbits I think. You can cover different azimuths and elevations, and if you're not at the equator, your launch window and orbital inclination are coupled, as is the inclination to the launch azimuth, and the azimuth to the elevation, and the elevation and velocity to the orbital height. It's a mess, but it could be a mess of interesting possibilities)

          What I think is going on is that the angle is only ideal for one velocity. If you could lob the rocket faster, drag and orbital mechanics change things around and the optimal angle changes. Then you could reach higher orbits too. If you want to go there, you need a bigger centrifuge anyway though, because of the required velocity. Hence why they went with only one angle for now. So if you assume that the velocity is fixed right now to be the lowest viable velocity that enables orbital insertion, then I think there's only one launch solution.

          1 vote
          1. Eric_the_Cerise
            Link Parent
            Yeah, that makes sense. Big Picture, though, I think they're just aiming for the simplest MVP first draft, and if it works and makes money, then they get to start planning for some adjustability.

            What I think is going on is that the angle is only ideal for one velocity. If you could lob the rocket faster, drag and orbital mechanics change things around and the optimal angle changes.

            Yeah, that makes sense. Big Picture, though, I think they're just aiming for the simplest MVP first draft, and if it works and makes money, then they get to start planning for some adjustability.

            1 vote
  2. [14]
    Eric_the_Cerise
    Link
    Replacing the enormous first stage of rockets with a high-tech trebuchet. Not a new idea. I'm always surprised that they don't try building launch facilities at higher altitudes. Even a mile above...

    Replacing the enormous first stage of rockets with a high-tech trebuchet. Not a new idea.

    I'm always surprised that they don't try building launch facilities at higher altitudes. Even a mile above sea level, like from the Denver area, makes a launch much easier, avoiding the thickest bit of atmosphere. Obviously, you also generally want to be launching as close to the equator, as possible ... but there are locations that offer both.

    4 votes
    1. vektor
      Link Parent
      I think this is one of the cases where that might actually pay off. Sure, you need to lug the big centrifuge up there somehow. But that's a one-time job, and if the tech works the way they hope it...

      I think this is one of the cases where that might actually pay off. Sure, you need to lug the big centrifuge up there somehow. But that's a one-time job, and if the tech works the way they hope it does, that's going to be a huge advantage. You'll decrease launch costs by avoiding the thick atmosphere, at the cost of setting up one piece of infrastructure. Getting the payload on top of a mountain is super cheap, compared to all the large rocketry bits.

      Also, since you're not launching up a 3000t canister of low explosive, you don't really need to worry about there being ocean to the east of your launch site, just to make sure the explosion happens outside of the environment. You can slingshot the payload up, and if something goes really badly wrong either your centrifuge goes boom or the payload comes down waaaaaay downrange anyway - at which point you have better control over crash site and/or atmospheric burnup. In any case, managing the safety of people far away from the site becomes much easier.

      I'm usually not super hyped by gadgety tech like this, but this one seems quite interesting. A long way away, but definitely interesting. If it works, it might make economic utilization of space resources much easier. Imagine: You ship a CNC mill and a few robotic arms up to the ISS using conventional means, and then you throw the raw material up there. You can use that to build a lot of things on-site. For example parts for a matching launcher on the moon that shoots refined moon rock back to earth.

      4 votes
    2. [2]
      NaraVara
      Link Parent
      I was wondering this myself, though I have no idea how the math works out air-resistance wise. I suspect it may be that whatever advantages you get are offset just from the agglomeration effects...

      Even a mile above sea level, like from the Denver area, makes a launch much easier, avoiding the thickest bit of atmosphere.

      I was wondering this myself, though I have no idea how the math works out air-resistance wise.

      I suspect it may be that whatever advantages you get are offset just from the agglomeration effects of access to manufacturing capacity, a permissive regulatory system, and plenty of aerospace engineering talent as well as clientele.

      There is also an argument it's good to do this sort of early-stage R&D under suboptimal conditions knowing that if you get it to work at down low you can get it to work at altitude as well, but the opposite relationship won't hold. For stuff like this you probably want to be able to sell the technology to cities and countries independent of how far above sea-level they are.

      3 votes
      1. Eric_the_Cerise
        Link Parent
        It's basically the main point of Virgin Galactic's system ... use a plane to carry the rocket just a few miles up, get it above the thickest bit of atmosphere, and launch the rocket in mid-air ......

        It's basically the main point of Virgin Galactic's system ... use a plane to carry the rocket just a few miles up, get it above the thickest bit of atmosphere, and launch the rocket in mid-air ... same effect, the rocket needs, like, 80% less fuel/mass to get to space.

        Earth is the perfect "edge-case" size. It is ridiculously hard to get stuff off the ground into orbit. Elon Musk has speculated that, if the Earth were 10% smaller, we'd already be living on other planets; and if Earth were 10% larger, we'd never get off of it -- at least, not with "normal" chemical rockets.

        3 votes
    3. [10]
      mtset
      Link Parent
      I think the problem is generally that building things at high altitudes, at or near the equator, is quite difficult and expensive in and of itself.

      I think the problem is generally that building things at high altitudes, at or near the equator, is quite difficult and expensive in and of itself.

      2 votes
      1. [9]
        Eric_the_Cerise
        (edited )
        Link Parent
        I expect there are specific rocket-scientist reasons why it's more trouble than it's worth; otherwise, they'd be doing it. However, in general, this argument doesn't hold water with me. We...

        I expect there are specific rocket-scientist reasons why it's more trouble than it's worth; otherwise, they'd be doing it. However, in general, this argument doesn't hold water with me. We routinely build entire cities, entire advanced production facilities, etc, at high altitudes (again, eg Denver, and many other "mile-high" cities). I don't see what there could be that is specifically harder about building a giant concrete platform to shoot rockets off of.

        ETA: Actually carrying the rockets up to said platform could be challenging ... but still easier than lifting them up that high in the air, using a controlled chemical explosion.

        2 votes
        1. [7]
          vektor
          (edited )
          Link Parent
          Keep in mind that your choice of rocket launch site is severely restricted: East of it you generally don't want anyone to live, in case things go wrong. You also need to be at least somewhat near...

          Keep in mind that your choice of rocket launch site is severely restricted: East of it you generally don't want anyone to live, in case things go wrong. You also need to be at least somewhat near the equator. There aren't that many highly developed east coast mountain ranges. In fact, that rules out basically any proper mountain range I can think of. That might explain why they tend to be at low elevation.

          This device doesn't have that problem. Have they announced where they want to build the full-size thing yet?

          3 votes
          1. [2]
            Eric_the_Cerise
            Link Parent
            Not that I know of, but the article does explicitly talk about them launching at sea level ... which is what inspired my original comment.

            Not that I know of, but the article does explicitly talk about them launching at sea level ... which is what inspired my original comment.

            1 vote
            1. vektor
              Link Parent
              Might be because they have to deal with super heavy duty parts here. The bearings, shaft and arm of the centrifuge will be super heavy stuff for the final version. I could see you would want to...

              Might be because they have to deal with super heavy duty parts here. The bearings, shaft and arm of the centrifuge will be super heavy stuff for the final version. I could see you would want to make sure these can be brought in by sea, in case you can't ship them over land. Might even be you need to get them from ship manufacturers.

              2 votes
          2. cfabbro
            Link Parent
            From the FAQ:

            Have they announced where they want to build the full-size thing yet?

            From the FAQ:

            Where is the launch site?

            SpinLaunch’s Suborbital Launch Site is located at Spaceport America in New Mexico. The first Orbital Launch Site is in final selection in a soon-to-be-disclosed location in a coastal region of the United States. We are closely collaborating with the FAA and other governing agencies for launch site licensing.

            1 vote
          3. [3]
            mtset
            Link Parent
            I don't know that this is true, at least not from a regulatory perspective. The FAA is not, in general, super jazzed about people firing large explosive things over populated areas.

            This device doesn't have that problem.

            I don't know that this is true, at least not from a regulatory perspective. The FAA is not, in general, super jazzed about people firing large explosive things over populated areas.

            1. [2]
              vektor
              Link Parent
              Well, it's not going to be very large or very explosive. It's going to be a small vehicle with a small fraction of that being fuel. Ergo only very little explosive mass. What you do have is a high...

              Well, it's not going to be very large or very explosive. It's going to be a small vehicle with a small fraction of that being fuel. Ergo only very little explosive mass. What you do have is a high kinetic energy. but that's nicely predictable. If you know the exit velocity, you know the impact zone. If you can prevent the payload leaving the site at an off-spec angle or off-spec velocity, you can prevent it from impacting somewhere you haven't foreseen. Preventing off-spec launches could be as simple as putting a blast door in the way of the chute until you've reached spec velocity, and hardening the housing of the centrifuge a bit. At the relevant velocities, collision with almost anything that's denser than a gas is basically a guarantee for explosive destruction of the vehicle, so it won't get very far even if it penetrates the housing. You don't need a 200 km downrange exclusion zone, because there's no feasible way the vehicle is going to come down there.

              The thing with flying explosive things over populated areas is, they become a problem if they spontaneously fail to keep flying. Newton tells us this is not a concern here.

              2 votes
              1. mtset
                Link Parent
                I don't think this is true! If you look at their renders of the vehicle, it's a 2-stage rocket - with a high PMF compared to a traditional launch vehicle, sure, but still plenty of explodium to go...

                It's going to be a small vehicle with a small fraction of that being fuel. Ergo only very little explosive mass.

                I don't think this is true! If you look at their renders of the vehicle, it's a 2-stage rocket - with a high PMF compared to a traditional launch vehicle, sure, but still plenty of explodium to go around.

                If you know the exit velocity, you know the impact zone.

                Only assuming the aerodynamics work out perfectly. Once you're out of the lower atmosphere, sure, but that high-speed, high-pressure regime is precisely where things are most likely to go wrong, and even

                putting a blast door in the way of the chute until you've reached spec velocity, and hardening the housing of the centrifuge a bit

                can't guarantee that the fins don't break off, the housing isn't slightly deformed, etc.

                I'm not saying it's unsafe, I'm saying they'll have to prove to the FAA that it's safe, at least if they want to be allowed to launch over populated areas.

                3 votes
        2. mtset
          Link Parent
          It's not really a question of whether it's possible, but rather a question of whether it's cost effective. Remember, SpaceX is getting cost wins for their test program by doing the end stage...

          It's not really a question of whether it's possible, but rather a question of whether it's cost effective. Remember, SpaceX is getting cost wins for their test program by doing the end stage refining and burning of natural gas on site; space launch facilities need energy, water, fuel, and personnel in massive quantities. It's certainly possible that you'll get real, significant gains from building out that infrastructure, especially if you plan to launch in high volumes, but I wouldn't take for granted that it'll be cheaper than building a slightly bigger booster.

          See, for instance, the ultimate form of "just launch higher up" - air launch! It works for things like ASAT missiles, and there are companies working on it (notably Orbital's Stargazer), but there are many more failures, even in recent history (Stratolaunch Pegasus II, XCOR Lynx III, Stratolaunch Falcon 9 Air, etc etc).

          3 votes
  3. [2]
    NaraVara
    Link
    I had an idea for something like this when I was a teenager, though I was imagining a sort of MagLev train accelerator rather than a spinning are. I'm glad it turns out it's actually practical! I...

    I had an idea for something like this when I was a teenager, though I was imagining a sort of MagLev train accelerator rather than a spinning are. I'm glad it turns out it's actually practical! I guess it's unlikely to work for manned missions, but it seems like it would be a great low-impact platform for satellite launches.

    I can even imagine future space missions doing some elaborate combined-approaches. Like use a Falcon Heavy to get the big stuff up there, use the Virgin Galactic Unity to get the crew and a command-module up there, and just trebuchet up all the other stuff in quick succession with something like this. You'd functionally be assembling the spaceship or space station in orbit from parts.

    2 votes
    1. Eric_the_Cerise
      (edited )
      Link Parent
      There are many, many different versions of the "giant space gun train track shooting things into orbit" idea. Many can be designed to be safe enough for humans. The nutshell problem with most...

      There are many, many different versions of the "giant space gun train track shooting things into orbit" idea. Many can be designed to be safe enough for humans. The nutshell problem with most (all?) of them is that they require huge -- really, insanely huge -- start-up investment that depends on really high traffic to space, to pay back the investment, and until quite recently, humanity simply hasn't had enough "market" for launching stuff into space. I think that is changing now, but that's specifically because chemical rockets are getting so much cheaper (thank you, SpaceX) ... meaning that those alternative launch systems still cost the same to start-up, and so, will require even more space traffic, to justify their existence.

      My favorite was and is the launch loop, or Lofstrom loop, a 2000km long maglev bicycle chain that magically uses angular momentum to levitate most of itself 80 kms up above the atmosphere.

      ETA: One of my favorite points about launch loops is that small-scale prototype/models could be functionally useful and profitable ... eg, it seems very feasible to use small loops to cover 5-50 km stretches of water to work as an alternative for giant mega-bridge projects.

      4 votes
  4. [4]
    vegai
    Link
    I'm not into physics but I read from some place that the centrifugal forces required for escape velocity would be way too high for any equipment to handle. Can someone confirm? Or is the point...

    I'm not into physics but I read from some place that the centrifugal forces required for escape velocity would be way too high for any equipment to handle. Can someone confirm?

    Or is the point just to get as much momentum as possible and then use boosters or something like that?

    2 votes
    1. [2]
      cfabbro
      (edited )
      Link Parent
      https://www.spinlaunch.com/faq#p2 https://www.spinlaunch.com/space-systems#p2

      https://www.spinlaunch.com/faq#p2

      How will satellite structures and components respond to the high-g environment?

      During early feasibility analysis of SpinLaunch’s global architecture, one area of primary interest was g-hardening. As such, an in-depth evaluation into existing industry examples of high-g capable sensors and systems was undertaken. Early research identified promising examples of complex high-g systems in industry including artillery launched drones with deployable wings, propulsion, and optics. Following the completion of the 12 m prototype, a system capable of testing to over 20,000G’s, SpinLaunch’s engineering team began evaluating a variety of hardware packages at the 10,000G that components endure during the launch. Through this testing, we’ve been able to demonstrate the impressive ability of satellite systems to readily handle the centripetal environment. Learn more about adapting satellites for SpinLaunch on our Space Systems page.

      What makes SpinLaunch possible now?

      Modern carbon fiber and miniature electronics are the most relevant reasons why SpinLaunch has not been possible until recently. Carbon Fiber emerged as a high-strength composite in the early 1960s and only recently transitioned from limited aerospace applications to widespread industrial usage. Low-cost high strength to weight materials like modern carbon fiber are a critical part of what makes SpinLaunch possible while modern electronics, materials, and simulation tools allow for satellites to be adapted to the kinetic launch environment with relative ease.

      How fast is the launch vehicle going when it’s released it into the atmosphere?

      The Orbital Accelerator spins up to approximately 5,000 mph prior to releasing the launch vehicle. To date, we’ve conducted tests over 6x the speed of sound.

      https://www.spinlaunch.com/space-systems#p2

      The High-G Environment

      The centripetal high-g environment is unique and few testing environments exist. Leveraging the SpinLaunch 12-meter and 33-meter accelerators, which are capable of spinning hardware to 10,000g and up to five times a day, SpinLaunch engineers rapidly iterate through many design-analyze-build-test cycles to optimize satellite components for the centripetal environment.

      This engineering process has been used to develop high-g reaction wheels for 20kg and 200kg-class satellites, deployable solar arrays and electric propulsion modules. Even unmodified smartphones, action cameras, and telescope lenses have survived without damage. In comparison to mechanical systems, electronics are surprisingly simple to ruggedize for kinetic launch. Because of the relatively low mass of resistors, capacitors, and electronic chips, many existing designs can be flown without any substantial modifications.

      5 votes
      1. vektor
        Link Parent
        Basically: It's something to consider, but it's quite possible to design for. Many of the -you'd think- most intricate devices we want to send (electronics, optics) are already quite resilient off...

        Basically: It's something to consider, but it's quite possible to design for. Many of the -you'd think- most intricate devices we want to send (electronics, optics) are already quite resilient off the shelf. The most difficult is probably going to be mechanical components. I could imagine that a rocket turbo pump is not going to be ready for this, off the shelf.

        I think this system is going to really shine when transporting bulk goods. Think "I want to ship 1000t of steel to the ISS for on-site manufacturing". That's a few days of renting out this accelerator.

        1 vote
    2. Eric_the_Cerise
      Link Parent
      Short answer: Escape velocity is possible but very difficult, but doesn't matter ... they're not even trying for that. They're aiming for something like 1/3rd of escape velocity (still plenty...

      Short answer: Escape velocity is possible but very difficult, but doesn't matter ... they're not even trying for that. They're aiming for something like 1/3rd of escape velocity (still plenty challenging), then regular rocket the rest of the way.

      2 votes