Missing Episode: Ultra Seven is this and then some. Tsuburaya has a self-imposed ban on Episode 12. Out of the Hawaiian Dub, only episodes 21, 22, and 35 survived. In the Cinar/Turner dub, all episodes were dubbed, but between 1985 and 1994, Turner's own video copies of episodes 5, 6, and 7 disappeared. Strangely enough, the banned Episode 12 was dubbed and broadcast in the States, and can even be found online. Nowadays, "Super Weapon R-1" is banned due to parallels to the Fukushima-Daiichi disaster.
Was originally supposed to be a more hard sci-fi show similar to Lost in Space called The Ultra Garrison, but TBS urged a rewrite due to being too similar to rival show Captain Ultra, and the show was turned into Ultra Eye, where Dan was supposed to transform into Redman, who was also Ultraman Junior. The Capsule Monsters were supposed to be kaiju from Ultra Q and Ultraman, but Tsuburaya wanted to do more with their budget, so the capsule monsters became new monsters. Ultra Eye was reworked into Ultra Seven and the rest is history.
The Ultra Garrison proposal would have revolved around a team of astronauts and Robot Buddy "John", who lived in a space station called Mother and were Earth's first line of defense against alien invaders. The concept came off as too derisive, and the executives ordered Tsuburaya to rewrite it.
In addition to Ultraman Junior, there would be both good and bad monsters, and good monsters would fight on humanity's side. Ultraman Gaia saw this idea come to fruition.
In one draft, Dan would have been half-R-alien (possessing ESP), half-human.
One of Seven's preliminary costume designs looked similar to Ultraman Mebius.