Launch towers have various umbilicals, arms, and stabilizers connected to a rocket prior to launch. How is the Mechazilla 'claw' on the Starship Launch Tower different from the earlier launch tower connections? Is Mechazilla is a new type of arm, or just the name for this tower?
A diagram for the competing SLS launcher describes a variety of connections between the tower and rocket. The SpaceX's design appears somewhat different in early fabrication photos.
There are two aspects of the Starship Orbital Launch Tower that are different from earlier launch towers, but neither of them have to do with the claw or the umbilical connections.
The first aspect is the time frame in which the tower specifically, and the whole Orbital Launch Pad (including the Orbital Launch Mount and the tank farm) in general were constructed. This is not at all unusual for Texas – in fact, SpaceX has greatly benefited from the readily available highly trained workforce from the oil and gas industry, who are very much used to building complex piping, plumbing, and liquid storage infrastructure and large structures in a short amount of time – but it is somewhat unusual for the US space industry, especially the so-called "old space"; at least since the end of the US–Soviet space race.
The second aspect are the catch arms with the chopsticks (which are the reason why Elon Musk said "it looks like Mechazilla"). Nobody has ever even dared to think about catching a landing rocket in mid-air, let alone build a catching mechanism. No company except SpaceX is currently even landing orbital class boosters, so they are most certainly not catching them. (Note: Rocket Lab will indeed catch the Electron first stage with a helicopter.) Even some of the most hardcore SpaceX fans thought Elon Musk was joking when he reacted to a 3D animation of a landing booster created by a SpaceX fan by tweeting "We’re going to try to catch the Super Heavy Booster with the launch tower arm, using the grid fins to take the load".
So, yes, calling that aspect of the OLT "different" is (quite literally) the understatement of the century.
On the other hand, the umbilical arm that contains the connections for the Starship and the claw that grabs the top of Super Heavy to stabilize the stack, that is a very simple design that we have seen on other launch towers before. The only real difference is that, unlike other launch towers, the umbilical arm needs to not only swing out of the way of the vehicle, but also out of the way of the chopsticks and their carriage as the move up and down the tower. So, the umbilical arm is actually mounted on the back of the tower (as seen from the launch mount) instead of the side.
There was an aspect of the umbilical connections that was different in earlier iterations of the design, namely that there weren't going to be any. An earlier plan was to refuel Starship through Super Heavy, using the refueling connectors for on-orbit refueling of Starship and save the additional umbilical connectors. (Following Elon Musk's "the best part is no part" mantra.) However, while this saves an extra umbilical connector on Starship, it requires extra plumbing inside Super Heavy. So, once it became clear that a claw was required anyway to stabilize the stack, the decision to add umbilical connections to that arm was made.
It is prudent to always remember that SpaceX iterates very rapidly. What is the plan today could be obsolete tomorrow. They designed away the landing legs, they have (at least for the moment) designed away the hot-gas RCS thrusters, they designed away the stage separation system, they are investigating designing away the landing thrusters for the HLS Lunar Starship, they flipped from carbon composites to stainless steel, they flipped from transpiration cooling to heat shield tiles, they flipped from propulsive landing of Dragon to parachutes, they flipped from landing the F9 booster under parachutes to propulsive landing, they flipped from catching the fairings to scooping them, they gave up on reusing the F9 second stage, they deleted propellant crossfeed from Falcon Heavy, the number of engines on Super Heavy has changed half a dozen times, the number of engines on Starship might change (possibly to 6 vacuum engines), and they have only built around 100 Raptor engines, never flown a Raptor Vacuum, never flown a Raptor Boost, only flown a few Raptor Centers, none longer than 8 minutes and higher than ~10 km, and they are already outdated with Raptor 2.0 around the corner.
For example, Elon Musk has indicated that they might delete the iconic Starship flip'n'burn and try to catch the Starship horizontally. He jokingly suggested equipping ships with bouncy castles and dropping the F9 fairings onto them, which "of course" sounds crazy … but then again, if they seriously intend to catch a Starship horizontally, isn't that more or less what it would require?
