Ocean worlds are a promising environment for harboring extraterrestrial life. Their oceans, however, are often enclosed under a thick layer of ice. The current best estimate of the Europan ice crust thickness, for example, is 24 km. Thus, a key challenge to in situ exploration of these potentially life-rich waters is developing effective and efficient ways to penetrate the ice. Analytical and numerical thermal models of ice penetrators in cryogenic ice are available in the literature, but experimental validation of these models has been limited. To help close this gap, we have built scaled Model Validation Probes (MVPs) and evaluated their performance in the Europa Tower—a cryogenic vacuum chamber hosting an ice column of 0.75 m diameter and 2 m height, capable of maintaining ice at 90 K and surface pressure at near-vacuum (10^-3 torr), similar to the conditions found on Europan surface. The tests monitored the fundamental probe performance variables of power and penetration speed, and additional variables such as ice and meltwater temperatures, and rough measurement of melt-hole shape. Seven tests were performed, ranging from 500 W to 1,200 W of input power. Four probes reached ~1 m of cryogenic ice penetration, and three probes reached the bottom of the 2 m ice column. All probes had confirmation of hole closure and the presence of liquid water inside the closed hole. This is the first realistic Europa-environment testing (cryogenic and vacuum) with subsurface penetration, hole closure, and liquid water. Comparison of our experimental results to the seminal Aamot model modified to handle temperature dependence of ice thermal properties shows that probe efficiency was below expectations, especially for high power probes. A detailed comparison of the experimental results to full finite volume numerical models results in better agreement and reveals the parameter range over which the Aamot model is valid. These results validate the core of the Aamot model while giving insight into its regime of applicability and the important factors governing deviations from its assumptions. The result of these endeavors is a deeper understanding of the dynamics of cryogenic ice penetration, directing future technological development and mission planning to enable direct exploration of environments that may harbor extraterrestrial life.