[FPSPACE] Environmentally Non-Disturbing Under-ice Robotic ANtarctiC Explorer, ENDURANCE

[LARRY KLAES]

The follow-up craft to DEPTHX, the Environmentally
Non-Disturbing Under-ice Robotic ANtarctiC Explorer,
or ENDURANCE:

http://www.stoneaerospace.com/products-pages/products-ENDURANCE.php

ENDURANCE Mission Description:

The principal AUV (Autonomous Underwater Vehicle)
mission at Lake Bonney is to serve as a tether-less
programmable mobile platform for an onboard suite of
science probes. The concept (upper right figure) is to
deploy a compact vehicle through a melt hole in the ice
surface of the lake and thence to have the vehicle execute
a pre-programmed 3D grid sampling trajectory in order to
populate a voxel model of the scan volume with the scalar
science data. Each layer of the grid is scanned in strips,
raster style, with a strip width, ƒ´X, and length, L. In a
square search pattern samples will be taken in longitudinal
slices of width ƒ´X and the length of any side would be n*ƒ´X,
where n is the number of scan lines. This can be taken a step
further by rastering in the depth direction by an increment
ƒ´Z between layers. A sample volume equal to ƒ´X2ƒ´Z would
represent 1 voxel. The present grid being considered for
the ENDURANCE project is 10 m (width) x 10 m (length) x
1 m (depth) for fine resolution sampling. The grid is geo-
referenced to the melt hole coordinates (using GPS), and
the sub-ice positions are determined using a multi-stage
sensor fusion approach. Each geo-referenced voxel is then
populated with fiber sensor data (fluorescence spectrometer;
Raman spectrometer; dissolved oxygen; temperature;
ambient light; Raman bottom probe); aqueous chemistry
(chloride and conductivity); and an optical image.

Data for any given mission are stored redundantly on flash
disk for later recovery and analysis on the surface. Planned
mission duration is 8 hours between vehicle battery changes
and maintenance and it is planned for at least one mission per
day to be conducted in the field. The navigation system is
designed to permit the vehicle to work autonomously.
However, for safety and recovery surety reasons, a
backup nav system will be used that will limit range of
up to 1,000 m from the melt hole.