InVADER takes lasers on deep-sea expedition

16 May 2023

SETI Institute deploys robotic vehicle in marine ecosystem as prelude to potential use in space.

A platform christened InVADER, or In-situ Vent Analysis Divebot for Exobiology Research, is about to take an optical sensing payload to the Kingman Reef and Palmyra Atoll region of the North Pacific Ocean.

The goal is to test the performance of the platform's sensors as they explore, sample and characterize the seabed, as a step towards InVADER's potential role carrying out similar tests in the future in oceans of other worlds such as Europa and Enceladus.

"Our technology will revolutionize oceanography like digital photography disrupted film photography," said Pablo Sobron, InVADER project leader at the SETI Institute.

"Scientists will no longer have to collect and ship samples to a lab and wait weeks for the results. InVADER will do it in just a few hours and with zero environmental impact. This approach will allow scientists to learn more about the ocean much faster, which is essential for protecting it."

Announced in 2019 and developed jointly by the SETI Institute, NASA, JPL, and sensor specialists Impossible Sensing, the InVADER platform was tested in 2021 by tethered deployment off the Oregon coast, to study the underwater hydrothermal systems of the submarine volcano named Axial Seamount.

Now the platform is going mobile, deployed from the research vessel E/V Nautilus as it visits the Kingman Reef and Palmyra Atoll during May and June 2023. Mounted on the ship's remotely operated vehicle (ROV) Hercules for InVADER's first use on a mobile platform, the goal is for InVADER to find marine minerals and catalog biodiversity around undersea vents on the seabed faster and more affordably than existing methods.

Testing will include engineering trials and data verification studies, comparing samples analyzed by InVADER on the seafloor with parallel analysis carried out ashore.

Raman spectroscopy on the ocean floor

The heart of InVADER is a laser spectroscopy suite that brings long-range and ultra-high sensitivity laser Raman and laser fluorescence spectroscopy to the seafloor for the first time, according to the project team.

Carrying out spectroscopy on the ocean floor is a challenging prospect, but Raman spectroscopy has long been thought a good match with the demands of this particular application. It is better suited to analysis of substances residing in an aqueous environment than infrared spectroscopy, and its components can be fiber-optically coupled in pressure resistant housings for use underwater on ROVs.

InVADER is capable of "unprecedented" high resolution measurements at active hydrothermal vents on the sea floor, said the project, and its optical sensor package is articulated to allow study of areas up to 2-meters by 2-meters in size.

"The optics continuously adjust the focal length to handle the ocean's varied topography while maximizing signal return, making the tool adjustable for on-the-fly surveys limited only by the speed of the underwater vehicle," noted the project in its InVADER literature.

"The Divebot also introduces an advanced spectrometer capable of analyzing mineralogical and organic composition right on the device itself, making it perfect for missions with limited or no ground support. While these vent characteristics can be analyzed using existing technologies, such analyses cannot, at present, be conducted simultaneously, in an autonomous, non-destructive rapid way."

Compositional maps created by InVADER will offer insights into the seabed's mineral resources and microbial metabolisms, paving the way for future autonomous exploration of vents located in other oceans on Earth, as well indicating the technology's possible use elsewhere entirely.