Returnal locks off a lot of areas from the get-go, and you'll have to permanently upgrade your suit to access them. Some areas are covered with a red laser floor, usually blocking off items and chests. To be able to walk across them unharmed you will need to unlock the Promethean Insulator upgrade. Here's how to get it.
Read More: Unlocking the Grapple Hook
Returnal: How to Walk On Red Floors
To walk on red floors in Returnal you will need to unlock the Promethean Insulator upgrade. This is located in the Fractured Wastes area, in a side door off of the main hub. You'll need to use an Atropian Key to get inside, and will be dodging lasers to get to the upgrade. Once you have it, it will permanently change your suit, allowing you to access the red floor hazard areas.
Using the Promethean Insulators
To use the Promethean Insulators you just need to jump down onto red floors. You'll still react to the hazard but won't take any damage and won't lose your Adrenaline. You can now access new areas and get items that were previously unreachable.
That's all you need to know about walking on red floors in Returnal. For more help with the game you should head over to our guide on getting to Underwater areas. Elsewhere there's our look at earning Ether.