One of the brutal truths about getting things off the Earth and into space is contained in something called The Tsiolkovsky rocket equation, which, to put it absurdly simply, means that most of the volume of a rocket leaving Earth will be needed for fuel. That’s why the rockets you see are huge towers of fuel and oxidizer with just a little area up top for the payload. A startup company called SpinLaunch is hoping to work around this grim equation by spinning rockets really, really fast in a circle. That name may have given it away?
The company just had its first successful test of the system on October 22, sending a test vehicle “tens of thousands of feet” into the sky.
The process is known as “kinetic launching” and utilizes a huge electric motor-powered centrifuge called the Suborbital Accelerator, which looks kind of like a turbocharger the size of the Statue of Liberty.
The Suborbital Accelerator is a huge vacuum chamber (i.e. there’s no air to create aerodynamic drag) with a carbon fiber rotating-arm style centrifuge inside it. The arm spins the payload (which can include a second-stage rocket to potentially reach orbit) and then a high-precision mechanical release flings it out of that tube, where it then shoots out into space.
The current Suborbital Accelerator is about one-third the scale of the planned final one, and for this test the accelerator was only spun up to about 20 percent of its capacity, which was all that was needed to send the 10 foot test payload up those tens of thousands of feet.
Plans for a much larger Orbital Accelerator show a bigger angled vacuum chamber and release tube:
Essentially, the big spinner is taking the place of a conventional rocket’s massive and fuel-thirsty first stage, allowing for much smaller rockets with much better fuel-to-payload ratios to be developed.
Here’s a video SpinLaunch released of their test:
I’m guessing that membrane the rocket bursts through is there to maintain the vacuum chamber integrity, and is not just for dramatic effect?
The proposed launch vehicle does have a pleasingly old-school aesthetic about it, looking like a carbon-fiber Buck Rogers kind of deal:
The company claims that adapting satellites and other space hardware for the high-G spinning process is no big deal:
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.
I suspect that this method wouldn’t be suitable for crewed launches, though.
The company has already raised about $35 million, and they have a Department of Defense launch contract, so maybe we’ll be seeing more things yeeted into earth orbit in this massive mechanical discus style.