A new eye in the sky is transforming how we see our planet. Launched in February 2024, NASA's PACE satellite is providing unprecedented data on everything from ocean phytoplankton to wildfire smoke.
NASA's Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) satellite is providing revolutionary observational data on atmospheric aerosols, wildfires, ocean phytoplankton, and freshwater algal blooms. The satellite carries three primary instruments: the Ocean Color Instrument (OCI) and two polarimeters.
Satellite Overview
The PACE satellite launched in February 2024. Its primary instrument, OCI, is a hyperspectral imager that observes Earth across a range of wavelengths from ultraviolet to near infrared. The satellite also carries the Hyper-Angle Rainbow Polarimeter 2 (HARP2) and the Spectro-polarimeter for Planetary Exploration (SPEXone), which measure how sunlight reflects off atmospheric particles and cloud droplets.
Although designed to study the ocean and atmosphere, PACE also observes land surfaces. The satellite views the entire Earth on a daily basis, with more frequent coverage at higher latitudes.
Atmospheric Observations
Aerosol and Dust Tracking
In August 2025, PACE ultraviolet measurements tracked a large dust plume moving westward from North Africa over the Atlantic Ocean. Simultaneously, data showed another plume to the north identified as wildfire smoke originating from the United States and Canada.
During January 2025 wildfires in the greater Los Angeles area, PACE data tracked particle size and shape, distinguishing between small smoke particles and larger particles such as dust and sea salt.
Ship Emissions and Clouds
The satellite observed ship tracks—streaks of brighter clouds—over the North Pacific, which are created when ship emissions modify marine stratocumulus clouds.
Wildfire Monitoring
PACE's instruments observe vegetation conditions, smoke plumes, and burn scars related to wildfires. OCI can assess plant health, stress, dryness, and pigment balance by observing several hundred wavelengths. On clear days, it can map burn scars and monitor their evolution, which provides data relevant to flood and landslide risk assessment.
The satellite uses ultraviolet wavelengths to detect smoke and estimate plume height, which affects particle transport and impacts on other systems. The HARP2 and SPEXone polarimeters measure light reflection to determine aerosol quantity, chemical properties, color, size, and shape, and can differentiate smoke from other particulates.
Kirk Knobelspiesse, a PACE remote sensing scientist, stated that data from the satellite aims to improve wildfire models and simulations.
Ocean and Freshwater Monitoring
Phytoplankton Communities
In September 2024, PACE distinguished phytoplankton communities including picoeukaryotes, Prochlorococcus, and Synechococcus in the eastern Atlantic Ocean. Diatom blooms, such as one observed off the Kamchatka Peninsula, play roles in ocean ecosystems by transferring carbon and supporting marine life.
Harmful Algal Blooms
The satellite detected elevated concentrations of cyanobacteria in three areas of the Great Lakes during summer 2024: Green Bay, Saginaw Bay, and western Lake Erie.
In March 2025, researchers used PACE data to track a harmful algal bloom of Karenia mikimotoi off South Australia, monitoring its expansion over several months.
Cloud Analysis
PACE's polarimeters measure sunlight reflecting off cloud droplets from multiple angles. Using machine learning, scientists can reconstruct 3D representations of clouds from this data, providing insight into cloud vertical structure and variability.
Data Applications
PACE data can provide information to emergency responders during wildfires and help local managers assess potential water quality concerns at reservoirs, beaches, and recreation sites.