Though humanity itself had been greatly enhanced by genetic technology, that so-called strength was limited to Earth's atmospheric conditions. Breathe in too much toxic gas, and they would still die.
This planet's atmosphere happened to contain gases harmful to humans. In fact, it was not just humans; several species in the Star Alliance could not remain exposed to Deep Blue Star's air for long periods.
This was a matter of living environments.
With humanity's current technology, they could not yet transform themselves into life-forms capable of adapting to every environment. Of course, human scientists had been working toward that goal and had already achieved many interim results. For example, human biologists had successfully developed broad-spectrum medicines based on various viruses, medicines that could cure nearly all diseases caused by microorganisms.
The reason for saying nearly was that the universe was vast and full of wonders.
In theory, humans would no longer die from inhaling a little toxic gas or being infected by unknown extraterrestrial microorganisms. But humanity would not recklessly roam about Deep Blue Star either, since humans themselves carried all kinds of microorganisms.
Those microorganisms could likewise be deposited on Deep Blue Star. That would not matter much on other planets, but humanity did not wish to harm the Deep Blue Star People. Thus, whenever humans went out wearing Tactical Armor, the armor's surface was disinfected to prevent a devastating blow to Deep Blue Star's ecosystem.
These were standard procedures for humanity when landing on a Life Planet. Upon returning, they also had to undergo disinfection, scanning, and testing. So plots where someone filmed on Earth brought a virus back aboard a spaceship would not happen. Even if someone deliberately tried it, they would be detected.
Humanity possessed extensive experience in landing on Life Planets. It was the kind