From Kerbal Space Program Wiki
The Stamp-O-Tron Ground Anchor is a deployable cargo item used to anchor vessels to a planet or moon's surface.
Product description
“
_Occasionally, even the most seasoned of rocket jockey wants to be safely back on the ground - and what better way to securely show your affection for gravity than by clamping yourself to it?The Stamp-O-Tron ground anchor provides a secure point to which you can attach other parts with EVA construction, including docking ports if you'd like to park a larger vessel safely.
Expect stocks in C7 Aerospace Division to jump if negative gravity is ever a real thing.
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— C7 Aerospace Division
”
Usage
The Stamp-O-Tron Ground Anchor can be placed on any piece of ground whether flat, slated, or upside down. It is also a deployable part that can be attached to any surface of a celestial body.
To use the Ground Anchor, a Kerbal must equip it in their inventory when going on EVA. Because the Ground Anchor has a volume of 40 L (equal to a Kerbal's inventory limit), this means that the Kerbal must unequip all their other equipment (even the jetpack) in order to carry the Ground Anchor. Once in the desired location, the Anchor should be deployed through the Kerbal's menu. Upon a successful deployment of the Ground Anchor, the four bolts will drill into the surface, ejecting a dust plume and locking the anchor to the surface.
The Ground Anchor should not be constructed in EVA Construction Mode! Doing this will place the Anchor on the surface, but will not deploy it; it will not be anchored to the surface. If in doubt, check the four bolts; a properly deployed Ground Anchor's bolts will be lowered into the surface, while an improperly deployed Anchor will have all four bolts in the original, undeployed position.