Centrifuge-based space launch company SpinLaunch got a welcome vote of confidence as they announced that they had signed a Space Act Agreement for a suborbital launch of a NASA payload later this year.
The agreement, made under NASA’s Flight Opportunities Program, is not unique. Funded by NASA’s Space Technology Mission Directorate, NASA has made these agreements with a variety of space-focused companies, like Blue Origin, SpaceWorks, Honeybee Robotics (since acquired by Blue Origin) and others. What makes this different is SpinLaunch’s method: throwing projectiles into space, instead of using chemical rockets.
SpinLaunch’s goal is to accelerate bullet-shaped projectiles to over seven times the speed of sound using a huge 100m centrifuge inside of an even larger vacuum chamber, then release them out of a launch tube into the atmosphere. The projectile ascends to the upper atmosphere, where its outer shell of heat-resistant composites falls away and a small rocket carries the payload the rest of the way into LEO.
This approach is unique among launch companies. Since initial ascent is the most difficult and fuel-intensive part of any launch, they aren’t the only companies exploring non-rocket-propelled first stages: Virgin Galactic launches from underneath a quadjet cargo aircraft, for example, and Canada’s own SpaceRyde is working on carrying rockets up on stratospheric balloons. But SpinLaunch are the only ones making a go at attempting this sling-to-orbit approach.
If it works, it will be revolutionary. Switching from rocket propellants to electric launch would dramatically reduce the carbon footprint and environmental impact of space launches, as well as the resources they consume. It would reduce the cost of launches — SpinLaunch aims to get costs down to under $2000 per kg, potentially down to hundreds of dollars per kg as the system matures. It isn’t suitable for humans, who can’t withstand the g-forces involved, but it could be ideal for small satellites.
But there is skepticism over whether it will work. Releasing the payload at the exact right time to launch will be challenging. The rotor will be moving so quickly that it will have to accurately release within a millisecond. If it fails to release at exactly the right time, the payload will hit the chamber wall with potentially catastrophic results.
Being able to maintain a huge vacuum chamber is also going to be tricky enough, as even pinprick holes can create serious issues. Keeping it sealed with a 300 foot centrifuge inside and recreating the vacuum again and again after each launch, though? That could be an enormous, even insurmountable obstacle.
(Ben Miles looked at their patents, however, and concluded that they aren’t trying for a complete vacuum, however, and so it “falls within the realm of feasibility”)
Skepticism or no, SpinLaunch has already had some success. Their smaller-scaled test launcher, the suborbital accelerator located in New Mexico, had a successful test-launch in October of 2021. The test launcher, 33 meters in diameter, successfully fired a 3 metre long projectile into the sky that reached an altitude of (according to SpinLaunch CEO Jonathan Yaney) “tens of thousands of feet.” But that test was only at 20% of maximum power, and the vacuum chamber is substantially smaller than the full-sized chamber. The jury is still out on whether it can scale up.
That’s why NASA’s agreement could be a vital sign of viability. NASA will be working with SpinLaunch to use this suborbital accelerator to (according to the release) “manifest and fly the first NASA payload on a developmental test flight later this year and provide means for post-flight recovery of payload back to NASA.” SpinLaunch will take NASA’s payload, send it into the sky, then they’ll work together to assess whether and how the system can be used by NASA to get small payloads into LEO.
Yaney said that the NASA deal “marks a key inflection point as SpinLaunch shifts focus from technology development to commercial offerings,” and that the deal shows that SpinLaunch “has materialized into a technically mature and game-changing approach to launch.” SpinLaunch aims to have their full-sized launcher ready to go by 2025.
Where their launchers will be located is an ongoing discussion; while there has been speculation that SpinLaunch might work in concert with Maritime Launch Services, though there’s been no announcements to that effect.
Considering the strong interest in the company by the American Department of Defense and its Defense Innovation Unit, an American launch complex seems likely. Even Rocket Lab built an American-based launch complex to service the lucrative US defense market. But if there’s enough international demand, and if the challenges are overcome, other SpinLaunch launch centrifuges could be constructed in other locations. MLS might be one such location, but as of now it’s difficult to say.