Enhanced pseudo-true colour composite of the United Kingdom showing coccolithophore blooms in light blue. Image acquired by MODIS-Aqua on 24th May 2016. Data courtesy of NASA.
This week hopes to see the launch of NASA’s Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission. It will be launched by a SpaceX Falcon 9 rocket from Florida’s Cape Canaveral Space Force Station, however, the original schedule of a launch on the 6th February was delayed by unfavourable weather conditions. It is currently scheduled for launch on Thursday 7th February, with the intention of putting PACE into a sun-synchronous polar orbit at approximately 677 kilometres.
PACE aims to improve our understanding of the health of the world’s oceans, together with improving knowledge of air quality and climate. It will be particularly useful for understanding for the ocean and the atmosphere exchange carbon. It will also monitor aerosols in the atmosphere, such as sea spray, smoke and desert dust; which will be useful for monitoring air quality and its impacts on human health.
PACE has three instruments:
- Ocean Color Instrument (OCI) is an optical spectrometer with a cross-track three hundred and sixty degree rotating telescope, together with a half-angle mirror and solar calibration mechanisms. This will help OCI avoid sun glint and inhibit image striping, meaning that its signal-to-noise ratio will rival or exceed previous ocean colour instruments.
- Hyper Angular Research Polarimeter (HARP2)
- Spectro-polarimeter for Planetary Exploration (SPEXone),
OCI’s operational approach to measure the ocean has been used successfully on many previous missions such as the Coastal Zone Color Scanner (CZCS) between 1978 and 1986, Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) between 1997 and 2010, together with the current the Aqua and Terra instruments on the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments, and the Suomi National Polar-orbiting Partnership Visible Infrared Imaging Radiometer Suite (VIIRS). However, OCI will measure ocean colour from the ultraviolet to infrared wavelengths at a much richer level than previously seen with NASA sensors, while the other two instruments will provide data on atmospheric clouds and aerosols as well as support atmospheric correction of OCI data. Having undertaken a lot of work on ocean colour over the last thirty years, we’re really excited to use and perform research with the data from this mission.
One topic PACE will be used to study is the quantity and movement phytoplankton at the ocean’s surface, and the additional wavelengths should enable researchers to differentiate between phytoplankton species. This is critical to support an understanding of which blooms are harmful algal blooms, that can offer a danger to aquatic and human health, and which are the beneficial ones. It will also help improve our understanding how the phytoplankton are responding to climate change
One interesting fact about PACE is that between the fiscal years of 2018 to 2021, during the Trump administration, budget cuts were proposed which aimed to cancel PACE – Earth Observation was not a priority for that administration. In each of the these years, the US Congress rejected the proposed cut and restored funding to the mission.
PACE has a forecast mission life of three years, but NASA hopes it will exceed this and it carries enough fuel to last at least a decade. Following its launch, it’s expected to have a commissioning period of two months, and it is hoped that ‘first light’ data and images might be released before the end of that period. All data from PACE will be publicly available.
We are excited about the possibilities of PACE, and will certainly look forward to see it’s first light images, and the datasets beyond.
