An unusual mission is underway on Lake Erie, off the Erie County shoreline.

If you were near the lake on Tuesday, there’s a good chance you saw that mission underway.

A ship named “The Thomas Jefferson” is using sonar to map the lake bed for the first time in decades.

The 208-foot ship is operated by the National Oceanic and Atmospheric Administration (NOAA).

The information they collect will be used to update nautical charts used by ships on Lake Erie.