NASA’s PACE mission aims to vastly increase understanding of the oceans, atmosphere

NASA’s PACE spacecraft inside a clean room at Astrotech Space Operations in Titusville, FL. Image: Adam Bernstein/Spaceflight Now

From the oceans to the atmosphere, there’s still quite a bit we don’t understand about our planet. NASA’s latest Earth-observing spacecraft hopes to greatly expand our knowledge of the globe in just a few years.

The PACE (Plankton, Aerosol, Cloud, ocean Ecosystem) spacecraft is the next payload to launch into orbit that will build upon more than 20 years of direct Earth observation. Dr. Nicola Fox, the associate administrator for NASA’s Science Mission Directorate, described the spacecraft as a “jewel” among the Earth-observing fleet.

“We have a theme in SMD of the search for life elsewhere. And so, we’re obviously excited by bringing the samples back from Bennu, going off and getting ready to launch Europa Clipper later this year to explore the ocean world of Europa, but PACE allows us to explore the ocean world here,” Fox said.

“And if you think that we’re the only planet right now that we know that sustains life and all of the life that we have here started in the oceans. And so, by studying the oceans and studying what’s in there and kind of learning about that, I actually think it’s a really key part of understanding how we would ever go about finding life, or signatures of life, on other worlds.”

After it launches, PACE will head to a 676.5 km (420 mi) orbital altitude with a 98 degree inclination. It will operate in a sun synchronous, polar orbit with 1300 local crossing time. It has a design life of three years, but it carries up to ten years worth of fuel.

That nominal three-year mission has a cost of $948 million, which includes launch costs, spacecraft development and operating support.

To study not only the oceans, but their interplay with the atmosphere via clouds and aerosols, PACE is sporting three main instruments:

  • Ocean Color Instrument (OCI)
  • Hyper Angular Rainbow Polarimeter (HARP2)
  • Spectro-polarimeter for Planetary Exploration (SPEXone)

OCI is PACE’s primary instrument and was developed at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Together with the two polarimeters, the spacecraft is designed to better understand ocean health as well as take measurements to increase our knowledge of air quality and climate.

“Greenhouse gases aren’t the only factors affecting temperature. There’s also these tiny particles called aerosols that reflect of absorb sunlight and also affect cloud formation,” said Kate Calvin, NASA’s chief scientist and senior climate advisor. “PACE is going to provide more information on oceans and atmosphere, including providing new ways to study how the ocean and atmosphere exchange carbon.”

NASA’s PACE spacecraft inside a clean room at Astrotech Space Operations in Titusville, FL. Image: Adam Bernstein/Spaceflight Now

OCI will be able to observe a much richer gradient of colors of the oceans’ surface, which in turn, will inform researchers about the specific types of phytoplankton are present. Jeremy Werdell, the PACE project scientist, said those microscopic organisms are important to study because they have a broad impact on both short-term and long-term measures of Earth health.

“Climate. Carbon moves through the system through phytoplankton. That’s incredibly important. Shorter term, fisheries. Fisheries rely on the base of the food chain, thus phytoplankton. Switching over to economy, fisheries obviously, but also, these harmful ones that contaminate drinking water, close beaches, close shell fisheries,” Werdell said. “Some order of 60 percent of the world or 50 percent of the world lives within 60 miles of the ocean. So, you don’t see it every day, but it does touch your life.”

As for how much of the Earth is being observed at any given time, Werdell said it depends on the instrument.

“The primary instrument, the Ocean Color Instrument, and HARP2, one of the polarimeters, are very, very wide swath and they will see all the real estate on Earth every day,” Werdell said. “The third instrument, SPEXone, is narrow swath. So, it will take close to 30 days to basically revisit the same piece of real estate.”

“Where PACE fits in, in particular for oceanography, is that given the target are these transient creatures, plants, algae, they don’t persist on the same scale that land plants do, it is incredibly important to get a view every single day,” he added. “What you target on land might be, will probably be there tomorrow, but there’s a really good chance the phytoplankton you’re trying to investigate will not be.”

Those involved with PACE said they are excited to researchers and those within the scientific community to get ahold of this new data set, which will start becoming available within 60 days of launch. But just as importantly will be making sure that the broader public, and especially decision makers, also has the ability to access and internalize this data.

“Understanding what’s in the water, who’s in the water, how’s that impacting our health, our ability to go to the beach, the health of our dogs that like to swim in the water. So, understanding what’s in the water can impact so much, even looking at fisheries, looking at aquaculture,” said Natasha Sadoff, NASA’s satellite needs program manager.

“Moving back a little onto land, we can also… understand more about air quality. So, there’s a lot of communities that are interested in PACE data to better understand how air quality will impact our health,” she added. “Air quality alerts, we can make them better. We can forecast more effectively and more accurately how aerosols will impact us.”

NASA will provide PACE data for free to the public on the website. Its mission starts with the launch, which is set for Tuesday, Feb. 3, at 1:33 a.m. EST (0633 UTC). If the mission isn’t able to launch then, there is a 24-hour backup opportunity on Wednesday morning at the same time.