Europa (a moon of Jupiter), has a vast ocean of liquid water where life could be thriving. A key remaining challenge is reaching such oceans: the thickness of the ice crust may range from 3 km to 50 km. Initial steps have been taken to develop analytical and numerical models of the thermal and physical dynamics of ice penetrators in cryogenic environments, but experimental validation of these models has been limited. To help close that gap, I am developing a melt probe concept to penetrate the ice crust and deliver scientific instruments to the underlying ocean at Europa.
We have built and experimentally tested the performance of a set of melt probes in the Europa Tower, a cryogenic vacuum chamber with an internal diameter of 0.75 m and an ice column height of 2 m, capable of maintaining ice at approximately 90 K and surface pressure at near-vacuum (10^(-3) torr), allowing for the testing of probes designed for the surface of Europa. My work is on the development, thermal modeling, and testing of such probes, designed to test the fundamental thermal and kinetic properties of melt probes in cryogenic ice. They include monitoring of power, temperature, and penetration depth, with wires stored and released via spools internal to the probe, allowing a continued connection after hole closure. We are currently validating the modeled dependency between the average steady-state velocity and the heater power input level. Future work will investigate the effects of ice density and impurities on penetrator performance. My goal is to provide the literature with a baseline model of melt probes in Europa temperature, pressure, and ice composition conditions. This will allow for further development of probes with optimized design and operations for reaching Europa’s ocean in the least possible time.