This project is solving the Seven Minutes of Science challenge.
Use the kinetic energy of the tungsten masses to burrow into the martian soil. Add some stabilizing fins to the back of the tungsten masses so that they fall nose first. Let them strike the martian surface at whatever speed remains burrowing deeply into the surface. This would allow some form of water or other sensor to get fairly deep under the surface. The sensor would need an umbilical with a transmitter that remains on the surface, maybe using airbag to protect transmitter from impact.