Some thoughts as I watch through this classic Japanese Special Effects TV series.
This episode, while pretty weird, is not quite so surreal as Terrifying Cosmic Rays. It introduces a lot of Ultraman lore, giving it the feel of kids playing and making up new gadgets and superpowers as needed. The worldbuilding details of Ultraman interest me, so I like to make note of them.

The level of space technology in Ultraman is always a little fuzzy. A few episodes ago nuclear weapons were being sent to Jupiter. Now we have a mission to Venus, using a very realistic launch vehicle, much like something from the Apollo program. The problem is that its sole crew is Prof. Mori, the rocket’s inventor. This not how NASA tends go about these things. At least they have the SSSP keeping an eye the launch. We get to see the Sub VTOL’s launch from the front of the Patrol’s HQ building for the first time too.
It turns out that there was something of a mini-space race going on, with the team’s science advisor Prof Iwamoto also developing a new rocket. He felt both designs needed more testing, but Prof. Mori decided a 99% chance of success was good enough. We check in on him as he heads to Venus. Mori, wearing a nice suit and tie under his spacesuit, puts on a live TV demo of both his ship’s artificial gravity and of his ability to eat a dinner in space with knife and fork. This excites Ide to an disturbing degree, but maybe he is just that impressed by the artificial gravity — which is a much greater development than a big rocket. At least they acknowledge the existence of the gravity system, which is more than a lot of sci-fi shows do. Of course Ide himself seems to have just invented the Pan-Space Interpreter, a Universal Translator. That’s an even better invention than artificial gravity, in my opinion.

With it they discover that the Alien Baltan are back, having survived Ultraman’s attempt at genocide. The Baltan suit has gotten a nice upgrade too, including three different colored flashing lights. Despite finding a new planet (called Planet R and existing… somewhere in the Solar System) they are up to no good and have intercepted the Venus mission. Prof. Iwamoto is able to upgrade the Jet VTOL (turns out he designed it) to have space flight capabilities so they can save Mori. It’s a big day for inventions, since Ide also unpacks a new weapon, the Mars-133, ray gun with, we assume, even greater power than the Spider Shot.
It’s all a Baltan trick. They’ve already taken over Prof Mori’s mind and are using him as decoy while they attack the Earth. Ide and Fuji are left behind to hold off a swarm of Baltan —this episode conveniently forgetting the previously established facts that the SSSP is an international organization with many branches. Ide freaks out at first, but then remembers the super-weapon he just invented.

Mori has been rescued from his ship, but since he’s actually controlled by the Baltan, they end up crashed on an unknown planet, Planet R we can assume. The Baltan grows to giant form, and Hayata follows suit, becoming Ultraman (somehow doing so from within the VTOL and without Cap noticing it). The Baltan have developed a defense against the Specium Beam though — and are very pleased with themselves about it too. The Baltan are jerks, remember. But Ultraman has a new weapon of his own: the Ultra-Slash!

The Baltan swarm on Earth continue their attack, destroying an oil refinery that suspiciously looks a lot like the one in “Oil S.O.S.” After getting the news from Planet R, they decide to abandon the swarm attacks, and merge into a giant form. The Baltan continue to operate in a way that suggests space, scale, and even individuality mean something different to them. Ultraman, still on Planet R, demonstrates his second new superpower of this episode: planetary teleportation!

The Baltan can ‘port around too though, and have already worked out a shield that defends against the Ultra-Slash. They chuckle to themselves about that too. Cue third new Ultra-power: Ultra-Discernment, an eye beam that takes out the Baltan shield. Another Ultra-Slash and it’s all over. Note that, despite all this fighting, and the energy drain of teleporting across space, Ultraman’s Color Timer never even flashes. It seems like everybody has already gotten tired of that trope.

Back on Planet R we learn a new, very interesting fact: Hayata’s body remains behind when Ultraman appears. So his consciousness does leave it and enter the Ultra form. It’s not a physical transformation. Looking back, this makes sense for maybe… a third of the previous episodes. Remember when Hayata has done things like becoming Ultraman while plummeting through the air? Everybody gets rescued when Prof Iwamoto arrives on his spacecraft, which is definitely not based on NASA style tech.

A continuity glitch, probably due to episodes being shown in a different order than written, is that Hoshino appears in an SSSP uniform, though he does not actually become a member of the team until a couple episodes from now.