Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

Goals to be achieved

The AWI provides the science payload for the envisioned TRIPLE-nanoAUV. The main goal is to develop a reasonable concept of a science payload suitable for both the terrestrial demonstrator scenario and the envisioned outer planetary oceans application. Due to the small size of the vehicle the scientific sensor suite has both to be very small in size and energy consumption but should also cover the basic environmental parameters with good accuracy to provide the best scientific output. Another important aspect is the longterm stability of the science sensor suite to ensure valid measurements over a prolonged deployment period.

Tasks within the project

  • Development of scientific application scenarios for the TRIPLE-nanoAUV for terrestrial and outer planetary oceans missions
  • Specification of possible field test scenarios for evaluation of the scientific payload and the AUV system
  • Development of a scientific sensor payload concept for both scenarios, including a possible sample extraction system.  
  • Identification and testing of best sensor technologies suitable for the TRIPLE-nanoAUV vehicle concept

Preliminary work (with one graph or one picture)

The AWI is one of the leading institutes for marine research in extreme and deep ecosystems, especially in polar areas. The involved working group „Deep-Sea Ecology and Technology“ has extended experience with the development, construction and operation of in situ measurement platforms like landers, moorings, crawlers and AUVs.

The AWI has made numerous successful deployments of his own in house AUV PAUL-3000 in polar regions. Beside the operation of the AUV, the AUV-Team has a focus on development and integration of modular payloads for the existing AUV. With those payloads the AUV can be rapidly altered to work on different research areas. Currently there is one pelagic payload with which the water column can be investigated and sampled and one benthic payload which is focused on benthic investigations with sidescan sonars and a high resolution still camera setup.

The involved working group has also extensive experience in the development and use of several other biogeochemical in situ sensors like benthic chambers, microprofilers and planar optodes and their operating platforms like crawlers which are operated in the deep sea and for long term deployments.

Implementation steps

Starting out with a concurrent engineering design study, the TRIPLE-nanoAUV project entered its concept design and evaluation stage. With respect the scientific payload, the focus of the AWI is on the following tasks:

  • Conceptual description of the scientific research questions which can be answered with a reasonable sensor suite on the nanoAUV and describing possible mission scenarios
  • Identification of the most likely environmental conditions the TRIPLE-nanoAUV will encounter on the terrestrial and outer planetary ocean scenarios.
  • Identification of suitable sensor technologies based on the envisioned mission scenarios, research questions and environmental conditions
  • Conception and development of a suitable science sensor suite for the TRIPLE-nanoAUV. The sensor suite should consist of a reasonable suite to measure the most important environmental parameters for characterizing the ecosystem within the hardware restrictions the needed miniaturization of the whole system will set. Furthermore the identification of possible points of interest for selected sampling and measurements should be possible.
  • To test the identified sensor technologies for their longterm stability and to estimate the possibilities of miniaturization a bread-board model of the sensor suite will be developed for laboratory and field tests
  • Conceptual design of possible science missions for the use of the nanoAUV on earth analogoues demonstrator missions. This includes both to utilize the nanoAUV for scientific output during possible simpler testing missions but also some concepts to test in the final subglacial lake demonstrator mission:

As one of the first steps the nanoAUV can be used with relativly simple trajectories and without the need to find its homing to the icecraft: Following a simple trajectory, the nanoAUV heads in one direction, ideally out from an ice covered area into the open ocean. As the vehicle moves linearly, it dives to close to the seafloor and returns to close to the ice / water interface or open ocean surface. This kind of underice missions still oppose a major risk for nowadays AUVs as the underice navigation and communication is a major obstacle. As the nanoAUV is specially designed for underice use we could use this technology together with the icecraft also for scientific campaigns under the thick shelf ice, which can stretch up to 100km over the ocean.

On its way out of the ice the AUV will measure salinity, temperature and pressure (to identify bodies of water, such as lenses of cold bottom water, or stratified upper water), as well as recording turbidity and chlorophyll concentrations. These inform on nutrient availability and resuspension in the area, and the freshness of material available to the seafloor community.

For the final demonstrator mission one possible mission topic could be the hypothetical search for hydrothermal sources within the subglacial lake. For this deployment, the nanoAUV is deployed with the icecraft into a frozen lake. An initial test following such a deployment may be to circle the borehole, then head for the lakefloor to make a circular investigation. A similar mission profile may also be used for deployments under the thick shelf ice of antarctica.

By mounting high resolution temperature sensors, turbidity meters, or redox sensors, the plumes of any hydrothermal sources below the ice can be identified, and some information derived on likely emission temperatures etc, as well as aiding navigation algorithms aimed at identifying the locations of black smokers and volcanic sources.