Notes from the Field

Little Things Make a Big Difference

February 7th, 2024 by Mike Carlowicz

“PACE is a mission that will use the unique vantage point of space to study some of the smallest things that can have the biggest impact.” — Karen St. Germain, director of NASA’s Earth Science Division

The skies above us are teeming with tiny particles of dust, sea salt, smoke, and human-made pollutants. The seas, oceans, and lakes around us are teeming with microscopic, plant-like organisms. In both cases, individual bits of these tiny living and inanimate particles are too small for your eye to see. But when billions to trillions of them aggregate in one place, we can see them from space. And these little things make a vast difference for life on Earth.

The particles in the air are known to atmospheric scientists as aerosols. Though the spray cans you might use for paint or hairspray do contain aerosols, the ones PACE will study are the flecks of carbon that rise from wildfires and smokestacks; the fine, dusty minerals that get lofted from deserts into the sky by strong winds; the nitrates and sulfates spewed by cars, trucks, and ships in their exhaust; and the salty spray from crashing waves and strong winds blowing over the ocean.

Why study them? Because those particles influence air quality, sometimes making it unhealthy to breathe, especially if you have asthma or heart and lung conditions. Pollution and smoke don’t observe borders – we all share Earth’s air — so it’s important to know something about the sources and types of particles floating around us. On the positive side, the bits of mineral dust or smoky aerosols can sometimes fertilize the ocean, providing nutrients for phytoplankton to bloom. 

Aerosols also affect weather and climate. Tiny particles in the air reflect sunlight, and how much they reflect affects how much the land and ocean surfaces heat up. Aerosols also “seed” the formation of clouds: they provide surfaces on which water droplets form (condensation nucleii) as they aggregate into clouds. One of the great unknowns in our models of climate change is what role will aerosols will play in changing rainfall and snowfall patterns and in the heating or cooling of our atmosphere.

Though NASA has been studying aerosols from space for decades — observing where they are and the abundance of them — PACE and its SPEXone and HARP2 polarimeters will change the game. The instruments will tell us the shape and size of aerosols, helping us answer questions about where they come from and how they might influence other parts of the Earth system.

The other little things that PACE will examine have names like diatoms, coccolithophores, cyanobacteria, algae, and dinoflagellates. To borrow and mangle a quote from one of my favorite movie characters — Annie Savoy in Bull Durham — if you have three phytoplankton, they can’t do much. But if you have 300 billion of them, they can build a cathedral. Well, maybe not a cathedral, but they can develop into vast blooms that have a profound impact on life on this ocean planet. 

Phytoplankton grow constantly on Earth and just about anywhere there are open, sunlit patches of water. When conditions are right, the growth of these microscopic cells can blossom to scales that are visible from orbit for days to weeks. 

Phytoplankton are to the ocean what grasses and ground cover are to land: primary producers, a basic food source for other life, and the main carbon recycler for the marine environment. They are floating, plant-like organisms that soak up sunshine, sponge up nutrients, and create their own food (energy).

Why do we need to study these tiny organisms with PACE? While humans don’t really consume phytoplankton for food, the little floaters are fuel for the zooplankton, fish, and shellfish that we do eat. We also need to care about phytoplankton because they can influence water quality and human health. Some species of phytoplankton produce toxins that are dangerous to humans and animals; others can grow in such abundance that they crowd out other species or deplete the water of necessary oxygen. 

Speaking of oxygen, phytoplankton produce a lot of it. Somewhere between 20 and 50 percent of the oxygen on Earth — some in our air, a lot in the ocean — is made by phytoplankton as they use photosynthesis to turn sunlight, carbon dioxide, and nutrients into sugars. In the process, they also draw carbon dioxide out of the atmosphere and, in time, sink it to the bottom of the ocean.

Better understanding the phytoplankton in the ocean will help us better understand the fisheries that feed us and our economy, and it can ultimately help us work toward cleaner waterways. 

NASA and its research partners have been studying phytoplankton from space for decades, but mostly with just a few wavelengths of light. I am looking forward to the colors, textures, and details we will see with PACE’s OCI hyperspectral imager. As the PACE science team likes to say: we have been coloring the ocean with a box of 8 crayons, and now we are about to get a box with 128 shades of color. The leap in detail will allow scientists to better spot where phytoplankton are, but also figure out who (what species) they are.

And when PACE data are combined with observations from our recently launched SWOT mission — which studies the shape and movement of the surface of the ocean — it will be like going from the Earth-observing equivalent of the Hubble Space Telescope to the new James Webb Space Telescope.

Learn more about phytoplankton with these resources:

PACE Phytoplankton Exploration

The Insanely Important World of Phytoplankton

What Are Phytoplankton?

NASA Wants to Identify Phytoplankton Species from Space: Here’s Why.

As the Seasons Change, Will the Plankton?

Phytoplankton May Be Abundant Under Antarctic Sea Ice

Learn more about aerosols with these resources:

Just Another Day on Aerosol Earth

New NASA Satellite to Unravel Mysteries About Clouds, Aerosols

Global Transport of Smoke from Australian Bushfires

Aerosols: Tiny Particles, Big Impact

PACE StoryMap: Air (E)quality

NASA: Explore Air Quality

The Long and Winding Road to Launch

February 5th, 2024 by Mike Carlowicz

A few paths in life are short and direct; more of them are long and winding.

This week, a SpaceX Falcon 9 rocket will launch from Cape Canaveral Space Force Station carrying the PACE satellite, short for Plankton, Aerosol, Cloud ocean Ecosystem. Once in orbit 676 kilometers (420 miles) above our planet, the newest addition to NASA’s fleet of Earth-observers will look at the oceans and land surfaces in more than 100 wavelengths of light from the infrared through the visible spectrum and into the ultraviolet. It will also examine tiny particles in the air by looking at how light is reflected and scattered (using a method like looking through polarized sunglasses).

The combination of measurements from the new satellite will give scientists and citizens a finely detailed look at life near the ocean surface, the composition and abundance of aerosols (such as dust, wildfire smoke, pollution, and sea salt) in the atmosphere, and how both influence and are affected by climate change.

For NASA and the ocean science community, the PACE launch will be the culmination of 9 or 46 years of work, depending on when you start counting. For me, it will be the culmination of something that started in 1950.

“There is a greater than 50 percent chance I will burst into tears at the launch,” said Jeremy Werdell, a satellite oceanographer at NASA’s Goddard Space Flight Center since 1999 and project scientist for PACE since 2015. “We are standing on the shoulders of previous missions and the people who led them. And it has been a long and remarkable journey.”

NASA’s first attempt at measuring ocean color dates back to the Coastal Zone Color Scanner (CZCS) instrument, which flew on the Nimbus 7 satellite from 1978-1986. In 1997, the agency launched the Sea-viewing Wide Field-of-view Sensor on the OrbView-2 satellite. SeaWiFS collected ocean data until 2010 and fundamentally changed our understanding of phytoplankton—microscopic, floating, plant-like organisms that are the grass of the sea. That sensor is an ancestor of the new Ocean Color Instrument (OCI) on PACE. 

Other instruments and teams have observed the colors of the ocean. The Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on NASA’s Terra and Aqua satellites have been flying since 2000 and 2002, complementing and extending the record started by SeaWiFS. More recently, the Visible Infrared Imaging Radiometer Suite (VIIRS) instruments on the Suomi-NPP, NOAA-20, and NOAA-21 satellites have provided a broad view of ocean color. And several other instruments — like the Hyperspectral Imager for the Coastal Ocean (which flew on the space station), HawkEye (on the SeaHawk CubeSat), and the Ocean Radiometer for Carbon Assessment (which was flown on NASA research planes) — helped researchers test new ways to look at the sea.

For atmospheric scientists, the path to PACE also traces back across decades. In the late 1970s, the Advanced Very High Resolution Radiometer (AVHRR) provided some of the first looks at aerosol optical depth, a measure of how much dust and particles were floating in our skies. Later scientists began measuring such particles daily and around the world with the Multi-angle Imaging SpectroRadiometer and MODIS instruments on Terra. The OMI instrument on the Aura satellite, and its successor OMPS on Suomi-NPP, provided other unique views of aerosols. A HARP instrument  flew on a CubeSat from 2019-2022 and provided a direct test of the technology that now flies on PACE as HARP2.

The origin of PACE itself sort of started around 2007. NASA and other federal agencies asked the U.S. National Research Council to study and suggest new tools and measurements for studying Earth from space. Their report (known as a “decadal survey“) recommended a mission that ultimately led to the A(erosol) and C(loud) components of the PACE mission. The inspiration for new ocean color sensors then arose from a NASA climate initiative proposed in 2010.

By 2012, NASA scientists and engineers were starting to sketch out rough ideas for PACE, and the wider science community dug into the details in 2014. By 2015, NASA Goddard started hiring for a new mission—including Jeremy Werdell—and by 2016, the agency had announced the formal development of a PACE mission.

Between that moment in 2016—known as Key Decision Point A—and this week’s launch there have been thousands of hours of work by hundreds of people…including many months working through a global pandemic…and the methodical, thoughtful testing of every idea, every design, and every part. 

For me, the road to the PACE launch has also been long. 

I have spent 21 years of my life working for NASA, and yet this will be my first launch. I feel blessed to spend my days working with incredibly talented, visionary, and smart people. This launch feels like the culmination of a lifetime geeking out on Earth and space science. Several threads of my life will all tie together this week.

In 1950, a 7th grader in Newark, New Jersey, won an essay contest by writing about a trip to the Moon. My father was fascinated by science fiction—he still is—and by journalism. He followed America’s developing space program with interest and, in 1969, his youngest son was born two weeks after the Apollo 11 Moon landing. Though no one can remember clearly, I like to say my parents named me for Michael Collins, who quietly orbited the Moon for 21 hours while Neil Armstrong and Buzz Aldrin made the headlines below. (My mother often reminded me that she went through a similar 20+ painstaking hours of labor waiting for me to show up.)

On my first job as a magazine writer, I wrote in 1992 about the Mission to Planet Earth—first an international conference, then an early name for what became NASA’s Earth Observing System. I visited NASA’s Jet Propulsion Laboratory in 1994 to research my graduate thesis and by 1997 I had joined NASA Goddard, where I stayed for five years writing about space weather and space physics.

But then I traded one institution of exploration for another, leaving to write about ocean science for Woods Hole Oceanographic Institution (WHOI). It was during those years on Cape Cod that I learned a boatload about phytoplankton and harmful algae. I spent 11 days at sea in 2005 on the research vessel Oceanus, helping scientists gather water samples to track a pesky, toxic phytoplankton called Alexandrium fundyense. After decades visiting the ocean, I was living by it and learning about it daily. 

I rejoined NASA in 2008 and eventually joined Earth Observatory. Circumstances and generous colleagues allowed me to keep living by the sea, and so I brought my love of the ocean into my reporting. I also passed that love of the ocean and space to my children: Two have become marine biologists who study plankton, and one is an aerospace engineer working on satellites.

After so many years of my life intersecting with NASA and the sea, it just feels right that my first rocket launch should be a satellite that will bring us new eyes on Planet Ocean.

Boreal Summer

September 12th, 2023 by Fred Huemmrich and Petya Campbell, University of Maryland BalHmore County

Fieldwork notes, July 21-August 3, 2023

Summer fieldwork for our project, “Clarifying Linkages Between Canopy Solar Induced Fluorescence (SIF) and Physiological Function for High Latitude Vegetation,” once again took our team from University of Maryland Baltimore County north to the boreal forests of central Alaska. We visited this area in the spring to collect data during the very start of the growing season, and now we are returning to collect data during the peak of summer.

This project is part of the NASA Terrestrial Ecology program’s Arctic-Boreal Vulnerability Experiment (ABoVE). The goal of ABoVE is to improve our understanding of high latitude ecosystems, how these ecosystems respond to climate change, and how satellite data can provide information to describe ecosystem processes and aid management decisions.

Our study focuses on measuring light emitted by plants called solar induced fluorescence. Green leaves absorb light, and through photosynthesis take in carbon dioxide and water and produce oxygen and sugars. Fluorescence occurs during photosynthesis as some of the absorbed light energy is radiated out from the plant. The amount of light fluoresced is only a very small fraction of what is absorbed, which is why our eyes don’t see plants glowing. In our study, we use sensitive instruments that can detect this fluorescence. Our goal is to better understand the sources of fluoresced light and how to use this information to describe productivity in boreal forests and tundra.

Our study site is at the Caribou Creek flux tower run by the National Science Foundation’s National Ecological Observatory Network (NEON). In spring, we deployed automated instruments at the NEON tower site that continuously collect data. On this trip, we are checking on how they have been working.

In July there was a big change from our previous visit in April. In April, the area had a deep snow cover with temperatures dropping below 0°F, while during this visit the daytime temperatures were in the 80s F and the ground was now all green (images below).

The gated bridge at the entrance to the Caribou-Poker Creeks Research Watershed where we are working in the spring and summer.

The boreal forest landscape in the Caribou creek with a view of the NEON tower in the black spruce forest.

On the top of the tower we have an instrument called a FLoX (Fluorescence Box). The FLoX views a patch of forest from above, and every few minutes during the day it measures the reflected light and solar induced chlorophyll fluorescence. This provides us with a description of plant activity at different times of the day through the growing season (images below).

The boreal forest at our study site (top-left). Looking up at the NEON flux tower, the thin pole extending from the top of the tower is from the FLoX (top-right); looking down from the top of the tower at the pole from the FLoX and the boreal forest below (bottom-right); and Petya and Fred with our safety gear on (bottom-right).

Also at the site we have monitoring PAM (MoniPAM) instruments attached to shoots of the spruce trees. The MoniPAM probes shine pulses of light at individual spruce shoots to measure fluorescence and photosynthetic processes at the leaf level (images below). We put blankets over the probes for a while to dark-adapt the shoots to measure their response when unstressed. In the spring, we put the MoniPAM probes in easy-to-reach places when there was a lot of snow on the ground. On this trip, when we returned to check them in the summer, we found we had to really reach up to get them without the snow to stand on.

MoniPAMs measure fluorescence of individual spruce shoots to describe photosynthetic processes. MoniPAM probe on a spruce tree views the spruce needles inside the clip (left); Bue blankets hang on the trees to cover the MoniPAM probes to dark adapt the shoots during the day (right).

One of the great things about working in the boreal forest in summer is that there are yummy berries to snack on, such as cloudberry (left) and blueberries (right).

From the ground, we collected reflectance and fluorescence measurements (similar to the data collected by the FLoX) of individual plants in the FLoX field of view and a variety of representative plants in the larger area surrounding the tower. These measurements will help us understand the local variability (images below).

A lot of the ground cover was cotton grass (Eriophorum spp.) that forms tussocks, which are tight clumps of grasses. The tussocks made walking through the area difficult, like walking on half-buried basketballs, so it was easy to twist an ankle, especially with a heavy backpack spectrometer on your back.

Measuring reflectance and fluorescence of different types of boreal forest plants. Collecting measurements at the base of the tower in the footprint of the FLoX (top-left); using the STELLA (top-right)—a multiband radiometer you can build yourself; and collecting data from a variety of different plants near the tower site (bottom).

Going into the field, you need to be prepared for pests both large (bear spray, that was never used) and small (mosquito repellent, which was heavily used).

We collected branch samples to make measurements of leaves and needles that we will use to parameterize models of vegetation fluorescence and productivity (images below).

Measuring leaf samples in our hotel room. Measuring photosynthesis rates (top-left); measuring leaf chlorophyll (top-right); measuring leaf level reflectance and fluorescence spectra (bottom-left); and the variety of different species we sampled (bottom-right).

We took a little time off to visit some other places in the area. We saw musk ox, which are animals of the tundra but raised in captivity at the University of Alaska Fairbanks’ Large Animal Research Station. Their thick, shaggy coat keeps them warm through the frigid arctic winters. Under the long guard hairs is a soft wool called qiviut that musk oxen shed in the spring. Qiviut can be spun into a very warm and soft yarn. Small balls of qiviut yarn can sell for over $100.

Musk ox at the University of Alaska Fairbanks Large Animal Research Station.

On our last day in Alaska we visited the Cold Regions Research and Engineering Laboratory (CRREL)  Permafrost Tunnel Research Facility (images below). Permafrost refers to soil that has been frozen continuously for more than two years. The permafrost around Fairbanks, Alaska, is considered ‘warm’ (at a temperature of -0.3oC/-0.4oC) as compared to the permafrost in our other study site in the North Slope of Alaska at Utqiagvik (e.g., a temperature -3oC/-4 oC). This warm permafrost is very sensitive to the changes in soil temperatures that can result from fires, rain events, and other disruptions that can cause permafrost thawing. Thawing permafrost can result in damage to roads and buildings and cause disturbance in forests.

The permafrost tunnel is dug into a hillside through earth that has been frozen for thousands of years. The tunnel reveals bones of extinct ice age animals, plants preserved since the ice age, and large ice wedges that can take hundreds to thousands of years to form. The ice wedges cause the formation of polygonal patterned ground, where the ground surface is covered with a pattern of shapes of slightly higher or lower ground. Our study site in Utqiagvik was in an area of high centered polygons, so it was interesting to be able to actually see the shapes of the underground ice that formed that unique landscape.

Looking down the permafrost tunnel (left) and a large ice wedge exposed in the tunnel (right).

Illuminating a Boreal Forest’s Spring Wake-Up

May 18th, 2023 by Fred Huemmrich and Petya Campbell, University of Maryland Baltimore County

Spruce trees in the boreal forest are evergreen and have green needles all year long.

The boreal forest is Earth’s northernmost forest. It circles the Earth at high latitudes, covering large parts of Russia, Canada, Scandinavia, and Alaska. These forests are some of the largest intact forests on Earth. They store a large amount of carbon—as much as (if not more than) is stored in tropical forests. The trees use photosynthesis to grow, and in the process, they take in carbon dioxide from the atmosphere. Carbon dioxide is an important greenhouse gas and a driver of global climate change, which is why it is vital to understand the rates of the transfer and storage of carbon between the atmosphere and the boreal forest.

Due to their vast area and remoteness, boreal forests are difficult to monitor from the ground. Data from satellites provide the means for observing these forests’ condition and detecting change across wide areas. In our project, “Clarifying Linkages Between Canopy Solar Induced Fluorescence (SIF) and Physiological Function for High Latitude Vegetation,” our team from University of Maryland Baltimore County, NASA’s Goddard Space Flight Center, and the University of Texas El Paso is working to develop advanced approaches to using satellite data to describe boreal forest productivity and detect stress responses. Our project is part of the NASA Terrestrial Ecology program’s Arctic-Boreal Vulnerability Experiment (ABoVE), a large-scale field study in Alaska and western Canada, whose overall goals are to make use of NASA technology to gain a better understanding of ecosystems at high latitudes, their responses to environmental change, and the effects of those changes.

A large proportion of the trees in the boreal forest are conifers, such as spruce trees (images above). These trees keep their green needles all year long. This makes it hard to determine when they start photosynthesizing in the spring, compared to deciduous trees, like oaks, where we can clearly see the growth of new green leaves in the spring.

The timing of the start of the growing season is key to determining the overall productivity of the forest and can be a useful predictor of possible stress events later in the summer. So, one of the goals of our project is to find ways to use light to detect when these evergreens “turn on” photosynthesis in the spring and actively start taking up carbon from the atmosphere.

This brought team members to Fairbanks, Alaska, right in the heart of the boreal forest. We arrived with our instruments in April 2023 to observe the very start of the boreal growing season. Our instruments use different methods to detect the onset and rate of photosynthetic activity in plants. One method we are using to identify photosynthetic activity in the evergreens is based on light that is actually emitted from the trees. Plants absorb light to power photosynthesis, but in the process of photosynthesis some of that light energy is radiated out from the plant; this is called chlorophyll fluorescence. This fluoresced light is very dim, which is why we don’t see plants glowing, but we can use sensitive instruments to measure fluorescence at leaf and canopy scales, which can even be done with instruments on satellites from space.

A second method is to detect very subtle changes in the color of the needles that are related to changes in the pigments in the leaves. Pigments such as chlorophyll, which makes leaves green, and carotenoids, which cause the yellow color of leaves in the fall, control potential rates of photosynthesis as well as provide protection to the leaves when stressed. These color changes are also subtle enough that we don’t see them with our naked eyes, but our instruments can measure and detect these pigment changes.

Riding on the snowmobile out to the flux tower site.

Petya Campbell wades through the snow to measure a spruce branch using STELLA, a do-it-yourself multiband radiometer. The snow was deep and soft, so you would sink up to your thighs if you stepped off the packed trail.

Instruments that are already on the flux tower measure the transfer of heat, moisture, and carbon dioxide between the atmosphere and the forest (images below).

The Caribou Creek NEON flux tower showing the tower and the hut that houses some of the equipment supporting the tower measurements. In the right picture, the boom for the FLoX can be seen extending to the right off of the top of the tower.

With the help of Jeb Timm, a NEON tower lead technician, we mounted our FLoX (Fluorescence Box) on the top of the tower. The FLoX looks down on the forest and measures the reflected light and solar induced chlorophyll fluorescence every few minutes continuously through the growing season (images below). FLoX measurements are similar to the data satellites provide, but with far more detail.

From the flux data we can determine photosynthesis rates and compare them with our fluorescence and reflectance measurements for relating the remotely sensed optical measurements to forest productivity. The continuous measurements allow us to examine the effects of varying light levels, moisture, and temperatures on the forest.

Installing the FLoX on the tower. Upper left, Jeb Timm hauls the FloX boom to the top of the tower. Upper right, the FLoX instrument (brown case) and the boom that holds the fiber optics that look down on the forest. Lower left, Petya Campbell wearing warm clothes and tower climbing safety equipment at the top of the tower. Lower right, the view for the FLoX looking down from the tower.

Near the flux tower we also put our MONITORING-PAM (MoniPAM) instruments whose probes actively illuminate individual spruce shoots with controlled pulses of light to measure fluorescence and photosynthetic processes at the leaf level (images below).

MoniPAMs measure fluorescence of individual spruce shoots to describe photosynthetic processes. Left and middle photo: MoniPAMs deployed in spruce trees near the Caribou Creek flux tower. Right photo: the MoniPAM probes illuminatied spruce shoots as part of their measurement cycle.

Besides setting up our instruments to catch the start of the growing season, we were hoping to be around when the spruce started to photosynthesize. This would allow us to test if we could detect the onset of photosynthesis through changes in needle reflectance due to changing pigment pools and/or fluorescence measured using a special leaf clip. To get consistent measurements using the same amount of needles, we had to pull off the individual tiny needles then line them up to make a solid mat to measure. And because photosynthesis and fluorescence are temperature sensitive, we had to make our measurements at the temperature the needles experience, so we worked on the deck outside in the cold (images below). The deck looked out on a big white spruce that was full of busy red squirrels who chattered and scolded us while we made our measurements.

Measuring spruce needles. Upper left, a solid mat of spruce needles for measurement. Lower left, pulling the individual needles off of the shoots and aligning them into the mat. This has to be done outside so the needles do not warm up. Upper right, measuring the fluorescence and reflectance spectra using the FluoWat leaf clip. Lower right, measuring the chlorophyll content of the needles.

Unfortunately, the temperatures mostly stayed below freezing the entire time we were there, so we didn’t get a chance to measure needles as they became photosynthetically active.

While we were there, there was also a NASA funded study of snow called SnowEx. In this part of the SnowEx study, researchers were studying changes in snow characteristics during the thaw period. The SnowEx field team made measurements of the snow on the ground, and NASA flew the Airborne Visible-Infrared Imaging Spectrometer – Next Generation  (AVIRIS-NG) imaging system on an airplane, collecting high resolution canopy spectroscopy measurements. We plan to make use of the airplane imagery in our study to see if we can identify changes in tree reflectance (which is noise to the snow scientists) indicating the start of photosynthesis.

We will return in late July to collect measurements during the period of peak summer forest productivity.

Happy Sixth Birthday to the CYGNSS Constellation

December 15th, 2022 by Chris Ruf

It’s been six years since the CYGNSS constellation was launched. Over that time, it has grown from a two-year mission measuring winds in major ocean storms into a mission with a broad and expanding variety of goals and objectives. They range from how ocean surface heat flux affects mesoscale convection and precipitation to how wetlands hidden under dense vegetation generate methane in the atmosphere, from how the suppression of ocean surface roughness helps track pollutant abundance in the Great Pacific Garbage Patch to how moist soil under heavy vegetation helps pinpoint locust breeding grounds in East Africa. Along with these scientific achievements, CYGNSS engineering has also demonstrated what is possible with a constellation of small, low cost satellites.

Artists rendering of the CYGNSS constellation of smallsats, with specular reflection tracks highlighted,

As our seventh year in orbit begins, there is both good news about the future and (possibly) bad news about the present. First the bad news. One of the eight satellites, FM06, was last contacted on 26 November 2022. Many attempts have been made since then, but without a response. There are still some last recovery commands and procedures to try, but it is possible that we have lost FM06. The other seven FMs are all healthy, functioning nominally and producing science data as usual. It is worth remembering that the spacecraft were designed for 2 years of operation on orbit and every day since then has been a welcomed gift. I am extremely grateful to the engineers and technicians at Southwest Research Institute and the University of Michigan Space Physics Research Lab who did such a great job designing and building the CYGNSS spacecraft as reliably as they did. Let’s hope the current constellation continues to operate well into the future.

And finally, the good news is the continued progress on multiple fronts with new missions that build on the CYGNSS legacy. Spire Global continues to launch new cubesats with GNSS-R capabilities of increasing complexity and sophistication. The Taiwanese space agency NSPO will be launching its TRITON GNSS-R satellite next year, and the European Space Agency will launch HydroGNSS the year after. And a new start up company, Muon Space, has licensed a next generation version of the CYGNSS instrument from U-Michigan and will launch the first of its constellation of smallsats next year.

The CYGNSS team will continue to operate its constellation, improve the quality of its science data products, and develop new products and applications for them, with the knowledge that what we develop now will continue to have a bright future with the missions yet to come. Happy Birthday, CYGNSS!