Recoverable autonomous sonde (RECAS) for environmental exploration of Antarctic subglacial lakes: general concept

The proposed RECoverable Autonomous Sonde (RECAS) will allow analysis and sampling of subglacial water while the subglacial lake remains isolated from the surface. The probe is equipped with two electrically heated melting tips, one on the bottom and one on the top of a cylindrical probe. When one of the tips is powered, the RECAS moves up or down similarly to a hot-point thermal electric drill. The electric power and signal cable is coiled inside the probe on an electric-motor-powered coil. When the lower tip is powered, the probe advances downwards by gravity. In order to move the probe up, power is applied to the upper heated tip and the coil motor pulls the cable, moving the probe upwards and melting the borehole above the probe. A conventional internal combustion engine electric generator on the glacier surface provides 9–10 kW of power to the RECAS via an umbilical cable stored in the probe. Electric power enables a penetration rate of 2.4–2.9m h–1, and thus 4–5 months will be required to reach a depth of 3500 m and return to the surface.