QT-RTG

The QT-RTG is a power generation item in Astroneer that supplies a constant stream of power. It is a smaller version of the RTG that is able to fit into a player's backpack.

Source
The QT-RTG may only be acquired from completing certain Missions or found rarely on certain planets, either in EXO Dynamics Research Aids that require Astronium or specific wrecks.

Uses
QT-RTGs may be placed on the player's backpack or on platforms to provide a steady stream of power at all times. This allows players to constantly run a Portable Oxygenator, providing infinite oxygen away from a base's oxygen supply.

Trivia

 * The QT-RTG was first shown on the March 12, 2021 SES_Dev Twitch stream.