NASA has partnered with SpinLaunch, which is developing a revolutionary accelerator based on centrifugal force.
Last November, we told you about it SpinLaunch, a company that wants to use centrifugal force to make it easier to put small payloads into orbit. Apparently, this concept piqued NASA’s interest a lot; US space agency Signed a partnership with the company. Together they will now test the viability of such a system in the context of certain routine operations, particularly those targeting low orbit.
Conceptually, the idea for SpinLaunch is surprisingly simple. The first step is to confine the payload to orbit in the SALS. It is a huge circular vacuum chamber that acts as a pocket for acceleration.
Real space slingshot
Once in, the assembly is rotated around an axis. Thanks to the vacuum that pervades the room, the machine can accelerate to tremendous speeds in complete silence, without having to resist the friction created by the gas molecules in the atmosphere.
When sufficient speed is finally reached, the load is separated from the axle; Because of all the kinetic energy accumulated during the first stage, the craft finds itself flung at dizzying speed through the chimney – Just like a pebble thrown by a slingshot. The only difference is that this object will rise much higher and faster. According to SpinLaunch, the projectile can theoretically exceed 8000 km / h without any problem.
This concept may sound strange, but it is not a fad from science fiction. The SpinLaunch demonstrated this during an impressive proof of concept in October 2021. With its A-33 prototype, it was able to send a 3-meter projectile to several kilometers in altitude by accelerating it over 1,600 km/h thanks to centrifugal force alone. And the machine was only running at 20% of its capacity!
Suffice it to say, SpinLaunch accelerators still have a bit of a spare… however this is only the beginning. The current jeep is already impressive, with a diameter of 33 meters. However, it’s pretty ridiculous compared to the beast SpinLaunch plans to put together. Its goal is to produce a SALS nearly three times larger, with a diameter of 90 metres. Thus it can send heavier objects to a higher level.
Reducing take-off restrictions
However, in realistic circumstances, this agreement will not be enough on its own. Its role is to accelerate the machine to bring it closer to the limits of space. This is a contribution that is far from neglected; It would greatly facilitate his placement in orbit by making it possibleAvoid major logistical constraints related to take-off.
In fact, to put a machine into orbit, it must meet two criteria; You must follow the right path, but above all travel in Very high speed and very accurate. It can then achieve an almost perfect balance between the forces that move the object away from the Earth and the gravity that brings it closer; Then we talk about orbit.
To allow an object to reach this speed, it is clear that it is necessary to transfer a certain amount of energy to it which directly depends on its mass (see Concept delta-v for more details). Usually the rocket takes care of this on its own with a rocket motor.
But the rockets then face a problem that hikers know all too well. To go far, you have to carry a backpack full of resources; But this tends to be quite heavy, especially at the beginning of the journey. And that can be stressful.
It’s the same in a missile. You must be able to “carry” the heart of the car, as well as all the fuel needed to ascend. And that weighs very heavy; For example, these fuels represent up to 91% of the total weight of the Russian Soyuz missile!
In practical terms, this means that the majority of the fuel is not used to propel the payload itself, but rather the rest of the fuel that will be consumed during the ascent. Furthermore, when the craft is close to Earth, it must struggle even more to overcome the gravitational forces pulling it relentlessly downward; The closer one gets from a point to sea level, the more powerful the system should be.
A cleaner, more economical and more interesting logistical system
So the challenge is to limit the amount of energy the car itself has to produce, and therefore the amount of fuel it has to carry. And that is exactly what this SALS is. At first, there will be no need to significantly increase the amount of fuel just to … carry the rest of the tank.
This has several obvious advantages in terms of logistics, operational costs and (possibly) the environment. Thanks to the massive acceleration provided by SALS, SpinLaunch claims that it will be possible to reduce the amount of fuel needed for launch more than 70%. The total launch cost can be divided by ten.
In addition, SALS relies on a Electrical engine. So it makes it possible to avoid the stage of filling the tanks and to carry out a large number of launches in a relatively short period of time. The SpinLaunch is therefore positioned as a clean and economical system, particularly suitable for routine operations in low Earth orbit.
A future standard for low-orbit operations?
But this system is not without limitations. The first and most obvious is that during this initial acceleration phase the machine will necessarily be exposed to absolutely tremendous forces. This means that in the absence of a revolutionary solution, our poor human body will quickly turn into a bloody jam. Therefore SALS will be reserved for loads capable of absorption tens of c.
Despite these limitations, NASA still considers this an interesting avenue in the current context, as access to space is becoming more democratic at full speed. In fact, it seems clear that these routine launches will continue to get more and more frequent. Therefore, it has become urgent to develop launch systems that are more convenient than the conventional rocket engine; SpinLaunch’s proposal is one of the most promising at this level.
So it will be interesting to follow the progress of this collaboration. If all goes well, we could gradually see a real paradigm shift in the light ejectors side. RocketLab, the current specialist in light load shooting, better watch out!
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