I’m curious what people think of the idea of SpinLaunch ? Their premise is to use an over-engineered trebuchet to throw satellites into orbit. I watched a video on YT and it appears like they’re very serious, but I have a hard time believing that this is a winning approach unless all satellites are super tiny (like pebbles.)
All the reviews of it by people with actual engineering knowledge say it’s a clear “no”.
I love the idea, but yes all the technical explanations of the concept I’ve seen indicate it’s only suitable for extremely small payloads. The g-forces involved also limit what can be subjected to a launch like this.
Would this be from a huge plane at 30 thousand feet or higher? ;^)
And robust, the acceleration on a normal rocket is high enough, but constant until they reach escape velocity. The required velocity and how it is produced (before the launch) means that they will be exposed to much higher G-forces and centrifugal forces on top of that, so the load is going to be pulled in 2 directions in the build-up to launch. Heat is also a big problem, although the use of a partial vacuum to spin up the projectile should alleviate some of the problems.
Without seeing more information, than the promotional videos, my small-brain says that you can’t have any loads with delicate equipment, food or, liquids. It is an interesting idea, but I’d like to see some real explanations of the science behind it.
A ground base station.
Tidal forces. I hadn’t considered that, but it may become an issue. Tidal forces, if you don’t know, are the differences in acceleration between different parts of a body due to the forces acting on it being different. In this case, the acceleration on the outside of the projectile will be higher than that of the near side (closer to the center)–because the outside has to travel a non-trivally longer path than the inside. This force may become important especially because it’s not something that normally has to be accounted for!
This is seen in The Martian, by Andy Wier, on one of the supply rockets, a bolt sheres and the load becomes unbalanced and the food emulsifies, turning into a liquid which exacerbates the oscillations of the rocket, causing it to self destruct.
According to NASA, the physics in the books were double checked to ensure they were accurate. I found some rudimentary research in a quick search, but haven’t had time to go into it deeply.
But the Spin system has to cope with the centrifugal lateral acceleration, as well as the longitudinal acceleration of the load, then the sudden change from high lateral Gs to zero lateral Gs as it is lobbed out of the exit chute into the air. If there is any movement at all in the load during the transition, it will make the vehicle very unstable. And movement means any liquids to solids that can liquify, such as food, have to be packed with incredibly low tolerances for movement within the container - the container can’t be flexible, so it can’t expand and contract with heat, but the liquid inside needs to be so densely packed that it cannot cause tidal movement within the container, which means extreme pressures when it warms up.
From the outside, there seem to be a lot of things that need to be addressed, before this system can become a reality. It looks like it is cleaner than a traditional rocket launch, but the question is whether they can overcome all the additional problems they are making for themselves.
I will be interested to see how they handle it. But I think it can probably only be used for a very small range of cargoes that can withstand the forces and not make the projectile unstable during transition.
There are probably more payloads than you might think that this will work with. The claim to have done a test launch with an iPhone (not to orbit but it was still subjected to very high g’s) and it was still working when recovered. Plus if it worked at all for getting things to orbit there is probably a huge demand for a relatively cheap way to get air, water, fuel and other commodities to orbit.