VESPER stands for Very energetic Electron facility for Space Planetary Exploration missions in harsh Radiative environments. It is a high-energy electron beamline for radiation testing, part of the CTF3 (Compact Linear Collider Test Facility) experimental linear electron accelerator at CERN.

An important application of the beamline is the characterisation of electronic components for operation in a Jovian environment, in which trapped electrons of energies up to several hundered megaelectron Volts (MeV) are present with very large fluxes. In September 2016, in collaboration with the University of Padova, VESPER was used for the first time to test advanced multi-level cell NAND Flash memories, usually used in space.