You know the two classic sayings: “It’s Not Rocket Science” and “I’m No Brain Surgeon” — well there’s a rather cool T-Shirt that mixes these up, resulting in: “I’m No Rocket Surgeon.”
In the 1865 novel From the Earth to the Moon by Jules Verne, a giant cannon is constructed that’s capable of shooting a projectile containing three men to the Moon. In reality, Verne’s scenario would have been impractical because a much longer barrel coupled with a timed series of detonations would be required to reach escape velocity while limiting acceleration to survivable limits for the passengers.
The brutal acceleration problem was solved in the 1900-1901 novel The First Men in the Moon by H. G. Wells. In this case, a reclusive physicist called Mr. Cavor invents a material he modestly names cavorite that can negate the force of gravity. I loved this story when I was a kid, and I dreamed of inventing my own maxite equivalent (suffice it to say that this is still a work in progress).
Did you ever read The Moon is a Harsh Mistress by Robert Heinlein? I’m hoping this is a rhetorical question but — if not — I urge you to order a copy immediately because it’s widely acknowledged to be one of his greatest works (I cannot understand why no one has made a movie of it yet).
A brief summary is that, in 2075, the Moon is used as a penal colony by Earth’s government, with three million inhabitants (called “Loonies”) living in underground cities. Eventually, the colony revolts against absentee rule from Earth.
A key element in the plot is that the Loonies have a mass-driver escape-speed induction catapult that’s used to launch metal containers loaded with wheat into space and on to Earth. The loonies end up using these containers to bombard the Earth in a bid to gain their freedom. Later, they try to persuade different nations on Earth to build similar catapults to send materials to the Moon.
With respect to the Earth catapults, Heinlein describes multi-kilometer long beasts that start off by accelerating their loads in a horizontal plane, and then angle up the size of a mountain — still accelerating — before hurling their loads into space.
In the real world, when we first landed on the Moon in 1969, it took a Saturn 5 with five powerful engines on the first stage generating 34.5 million newtons (7.6 million pounds) of thrust to get us into Earth orbit. By comparison, the single ascent engine on the Lunar Module employed a fixed, constant-thrust rocket with a thrust of about 15,000 newtons to achieve Lunar orbit.
Based on this, I could easily see Heinlein’s catapult working on the Moon, but I truly thought anything like this on the Earth was literally the stuff of science fiction. So, you can only imagine my surprise when my chum Alvin Brown pointed me to some interesting articles. Actually, these don’t involve a catapult. Instead, they employ a centrifuge (see SpinLaunch Hurls Payloads into Orbit and SpinLaunch Hurls Satellites into Space Using Giant Spinning Machine). Also, I just found this video on YouTube.
On the one hand, I find it difficult to wrap my brain around the centrifugal forces involved and the design problems that will have to be overcome to create devices that can survive the launch. On the other hand, if this technology comes to fruition, I can easily envisage myriad countries building SpinLaunch facilities and using them to hurl all sorts of things into space. What say you? Do you have any thoughts you’d care to share on any of this?