Sea Launch Spin Up

No matter how it seems in mass media, getting into space is still a difficult and expensive endeavor. Innovators around the world are hard at work developing platforms designed to get more and more into orbit for every dollar spent on launches. One firm that has gotten intermittent attention is Spin Launch a California-based firm that wants to lower launch costs by accelerating rockets using a giant centrifuge to reduce how much fuel needs to be used to get a given payload into orbit. By rapidly spinning a payload around in a 100 m diameter centrifuge you can accelerate an object to about 2000 m/s or a tad shy of 4500 mph. This initial thrust means your spacecraft can coast until the appropriate altitude is reached to deploy much smaller, and ideally cheaper, engines, that will allow your payload to enter orbit. Scott Manley has already done a great break down video explaining some of the underlying phsyics, what I want to talk about is what I think Spin Launch could do after they validate their platform.

In their current press releases Spin Launch shows a static large building with massive vacuum chamber and a centrifuge inside. This makes sense you want to show a conceivable future, so you don’t spook investors. The downside of a large static building comes in the form of what kind of orbits you can offer customers. When you launch a spacecraft from a given latitude you are limited to orbits that pass over that launch site. It is this challenge of orbital mechanics that is why the International Space Station orbits where it does, Russia and the United States both needed their crews to be able to launch from their respective countries and dock with the ISS. Now for infrastructure like the ISS that predictability is all fine and dandy, but for other national operators, there could readily be a desire to rapidly deploy constellations of spacecraft in less standardized orbits. The United States Department of Defense is a prime example of a consumer entity who may want to deploy a lot of satellites relatively rapidly with a particular inclination.

Being able to launch dozens to hundreds of 200 kg payloads at an inclination of the clients choosing with only a few weeks/days notification could well be within the wish list of current/future war planners. To meet that desire Spin Launch has two likely options (while still using their technology) 1) have a network of launch platforms at as many latitudes as financially feasible. Or 2) create a large floating platform capable of transporting a Spin Launch system optimized for sea operations.

By having a floating platform, you go from needing a network of static launch locations to one or two mobile systems capable of adapting launch parameters by simply floating to a new location. As political concerns change the Spin Barge could move from latitude to latitude ensuring strong space representation by its owners. And considering the nature of orbital mechanics these launches could happen hundreds or thousands of miles from the core conflict, but still be optimized for the needs of those on the ground.

Honestly this is on the wishy washy end of things. Without knowing what kind of fuel penalties are incurred by changing the inclinations of payloads launched by Spin Launch it is hard to predict how many launch platforms you need, and as a result whether the solution in search of a problem (my so called spin barge) makes any sense at all. For example if you can launch satellites where your mass penalty is relatively small to change your inclination by  you would simply divide 90 by 2*x to determine how many launch locations you would need to effectively reach any normal orbit you wanted. So if a 5 degree shift is cost effective you would only need 9 platforms to cover the entire planet. Which would likely be way cheaper than making  brand new seaworthy design.  So who knows, but I wanted to put some thoughts down as a just in case this does happen I can say “yep, called it”

Edit/Follow Up: After initially posting this on March 16th it appears the US SpaceForce has reqeusted $50 million to look into on demand rapid response launches by private industry to suppliment/support US satellite infrastructure. Assuming the US military and Spy agencies go for a collection of rapid response “high volume” spacecraft designs I can see a situation where some kind of ground based launch assist becoming the norm. The reason I mention high volume is based on how expensive it is to vet a given design for a particular launch system. The greater the diversity of these spacecraft the more expensive the vetting process and the lower the volume of units made that you can ammortize those develoment costs onto.