Copyright 2014 Robert Clark
Gravity measurements from Cassini have provided further evidence that Enceladus has a subice liquid ocean. It is being regarded now as a prime target in the search for extraterrestrial life. The question is how to reach that ocean through what may be 40 km of ice. There have been various proposals for drills. However, NASA has modeled the plumes seen to arise from the "tiger stripes" on Enceladus as coming from vents that attach to the ocean below. Then a simpler method may be to reach the ocean by traveling through these vents.
This graphic shows how the ice particles and water vapor observed spewing from geysers on Saturn's moon Enceladus may be related to liquid water beneath the surface. The large number of ice particles and the rate at which they are produced require high temperatures, close to the melting point of water. These warm temperatures indicate that there may be an internal lake of liquid water at or near the moon's south pole, where the geysers are present.
This method may work to reach subsurface liquid water for other outer solar system bodies expected to have them such as Europa, Titan and Ceres.
As a feasibility test we might try it to explore subsurface though deep-sea hydrothermal vents here on Earth.
According to this model the temperatures might reach a maximum of 400 °C. If we can develop a robot to travel through these conditions quite likely it would also work in the conditions for the vent systems of these outer solar system moons.
In an upcoming blog post I'll discuss how the Falcon Heavy at a 53 metric ton(mT) payload capacity and the first version of the SLS at 70 mT could each be used to conduct sample return missions from these outer solar system moons.