Spinlaunch Possibilities

 

 

 

Back in November 2021, Brian Wang’s Next Big Future  (and several pro & con Youtube videos), described how the startup company, Spinlaunch, managed to mechanically hurl a test payload into the sky.  The ultimate goal is to sling a payload so fast that it could reach orbit.  An interim goal would be hurling a rocket launcher at a lesser speed that would still be fast enough to replace the first stage of the rocket and greatly reduce fuel combustion used for launching material into space.

The test facility has what looks like a propeller with a giant arm on either side of a central hub.  The two giant arms turn at high speed inside a giant enclosed partial-vacuum chamber.  At just the right moment, the payload is released.  It rips through a membrane into the air and is flying.  The ground crew can then replace the membrane, place a new payload on the propeller arm, pump the chamber back down to vacuum, and start the propeller arm spinning up to launch speed for the next launch.

Of course, the spinlaunch would only be for cargoes.  People could not survive the several thousand g’s of the spinning.

My opinion is that it does not belong on Earth at all.  Maintaining even a partial vacuum requires that the containment chamber be very strong (read expensive).  More seriously, if the payload release were to be even a split second off target, the payload would not go through the release passage and then out through the membrane.  Instead, it would fly though the wall, destroying itself and possibly the building as well.

However, a spinlaunch on the Moon would have big advantages over one on Earth for four reasons.  First, the lunar non-atmosphere is a harder vacuum than anything that can be obtained on Earth; hence, there is no need for the giant expensive vacuum chamber.  Second, without a vacuum structure, the chance of a payload crashing through a wall and destroying the entire structure is much less.  Third, spinlaunching material from the moon would eliminate transporting fuel from the Earth, which would make transporting material from Luna to Earth orbit much more affordable. Last, but not least, launching from the Moon with 1 mile per second escape velocity is much easier than from Earth’s gravity well of 7 miles per second, and no atmospheric friction heating the payloads; so spinlaunchers could loft payloads with only a little rocket fuel for guidance.

For those reasons, Gerard O’Neill proposed using electromagnetic launch from the Moon to provide ore for industrializing the two (nearly) stable hover points described by LaGrange (especially L5 and L4).  O’Neill and his collaborators proposed an electromagnetic launching system, but the principal is the same.

The O’Neill colonies were proposed roughly a half century ago.  They were a wild dream then.  However, technology has evolved since then … and continues to evolve.  Major space entrepreneurs, such as Musk and Bezos, would be wise to invest a relatively small amount to keep Spinlaunch progressing.