These are the Tesla Roadster’s deployable skirts, which work with four rear-mounted fans to generate enough suction to hold the vehicle upside down, even when completely stationary. It'll help with track performance too.
This is the new Tesla Roadster's fan and suction system, which the company filed a patent for in April 2025.
Sides skirts and front and rear skirts deploy under the battery pack, sucking the car down at ~2G. Because the skirts can move, they have some compliance, so they can deal with road bumps, road debris, etc. As the speed of the Roadster increases, the front and rear skirts retract to allow for air-flow (venturi effect) under the vehicle.
Tesla: "Our multi-mode fan and ground sealing system acts as a downforce generator, pulling air out from beneath the vehicle. This provides enough suction to hold the vehicle upside down, even when stationary. Powered fans and active wings maximize traction and cornering speeds in all conditions, achieving massive downforce at zero speed."
In their patent, Tesla said: "In the first mode, a complete set of skirts creates a fully sealed bounded region under the vehicle with central fans generating maximum downforce at low speeds on smooth surfaces. In the second mode, a subset of skirts (primarily side skirts) modifies the bounded region while all fans operate to provide downforce in dynamic driving conditions with uneven surfaces. The system includes a control mechanism to selectively deploy skirts and operate fans based on driving conditions, optimizing between maximum downforce at low speeds and improved performance over varying terrain at higher speeds."