Tag: color

Fernanda Henderikx-Freitas: Scanning the Hawaiian Seas

Fernanda Henderikx-Freitas, assistant professor at University of Hawaii, is the lead principal investigator of the PACE validation team called the Hawaii Ocean Time-series program for validation of the PACE Mission in oligotrophic waters (HOT-PACE). The group is one of many in a campaign set out to gather data around the world to check the accuracy of information from NASA’s PACE (Plankton, Aerosol, Cloud, ocean Ecosystem) satellite up in orbit. She and her team recently took to the seas for the first segment of a three-year campaign to study the phytoplankton in the ocean surrounding Hawaii.

Where did you go for your field campaign and why did you choose that location?

We went to Station ALOHA, which is about 62.1 miles (100 kilometers) north of Oahu. It is a site that has been visited nearly monthly since 1988 as part of a long-term sampling program called the Hawaiian Ocean Time-series (HOT). We piggybacked on one of their monthly cruises, which last 4-7 days. We’re hoping to continue gathering data there for the next three years. Since there’s been oceanographic data collected at Station ALOHA for over 35 years now, we understand a lot of what the ocean properties should look like, which makes it a perfect location for a satellite validation site where data accuracy is so important.

A woman stands in the image facing toward the left. She is wearing a dark brown shirt and teal colored pants. Her right arm is lifted up toward a piece of machinery that is made of several cylindrical tubes and is surrounded by bright yellow piping.
MSc student Paige Dillen on HOT351 collecting water samples from the CTD rosette for the HOT-PACE validation project. Credit: Fernanda Henderikx-Freitas

How are you gathering your data?

We are focusing on the very basic information about how light interacts with water, which we need to validate PACE’s data. Whenever we see the clear sky overhead and we know the PACE satellite is close by, we’re going to be out there collecting water. We run seawater through special filters that get immediately frozen at minus 112 Fahrenheit (minus 80 degrees Celsius) for later analysis in the lab back on land where we determinate pigment composition and absorption properties by particles and dissolved materials in the water.

We also have a series of instruments that measure the total absorption and scattering properties of particles in the water at high resolution using a pump system where water is diverted from a depth of about 23 feet (7 meters) into the ship laboratories.

Finally, we have instruments that we throw in the water that look at the light profile in the water column, as well as another instrument that we point at the sky to look at optical properties of the atmospheric path between us and the satellite.

How do the instruments that you use compare to what PACE uses up in orbit?

PACE is a hyperspectral satellite, and on the ship we have hyperspectral sensors that look at both the absorption and scattering properties of seawater. These properties are key for informing satellite models that try to convert the raw reflectance signal that the satellite receives to meaningful quantities that we are interested in. For example, quantities of organic and inorganic carbon concentrations or phytoplankton-specific concentrations. Throughout our first cruise, which lasted five days, we had these instruments on the entire time, so that maximizes the chance of us getting a match up with the satellite.

We also have a hyperspectral radiometer that we use to profile the water column once a day while on the cruise — this radiometer has as many wavelengths as PACE has, and provides the closest type of data to the data measured by the satellite, which makes it incredibly important and useful in validation and calibration efforts.

How are you planning on using PACE data in your own research?

We are very interested in better understanding the relationships between bulk optical properties of the water and phytoplankton community structure, a research area that we think PACE is very well poised to help advance. Paige Dillen is a graduate student on our team who will go on every cruise to collect validation data for PACE and will also base her whole project on PACE. She’ll be looking at the relationships between pigment composition and phytoplankton absorption, which could help develop and improve satellite algorithms in the future.

What do you enjoy about field work?

I love seeing the night sky out here. You just look up and you see the Milky Way and meteor showers because you’re so remote. You can’t get it anywhere else. Seeing all the wonderful microscopic creatures is also amazing — we have a series of microscopes and imaging tools onboard that really help us feel connected with the water we are sampling. There is something very special about being able to collect your own data, it makes you feel like you’re completely involved in your research.

Header image caption: HOT-PACE team on HOT 351, July 2024, onboard the R/V Kilo Moana: From left to right: Angelicque White, Fernanda Henderikx-Freitas, Paige Dillen, Tully Rohrer. “We are so excited to have a role in providing these essential datasets!” said Henderikx-Freitas. Credit: Brandon Brenes. 

By Erica McNamee, Science writer at NASA’s Goddard Space Flight Center

Dennis Henry Captures the People – and Hardware – of PACE

Dennis Henry is the PACE project photographer at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

A man wearing a white clean room suit is seen from the shoulders up. He is facing away from the camera, arms outstretched and holding onto a large piece of a scientific instrument. The instrument is circular shaped. There is a circle in the center that is surrounded by another ring of a black circle. The center circle reflects the face of the man, who has a mask that covers his nose and mouth.
One of Denny’s favorite images that he took of PACE. Senior Engineer George Hilton adjusts a polarizer during GSE testing of the Ocean Color Instrument Engineering Test Unit at NASA Goddard Space Flight Center on December 10th, 2020. Image Credit: Dennis Henry

What is your background and what do you do for PACE?

I’ve been at NASA for about four years, but before that I was a freelance photographer, and a long time before that I wanted to be an aerospace engineer. I studied engineering for about a year and a half before I realized that it wasn’t what I actually wanted to do. So, I switched to photography! I came to NASA specifically to photograph PACE and Ocean Color Instrument. I feel like coming here brought me back to my previous space interests, and I was able to feed that interest while doing what I’m good at.

Two men and a woman stand together on a grassy surface near a body of water. The man to the left in the image is wearing brown pants, a red shirt, and a zip-up jacket. He is leaning slightly to the right. The man in the middle is kneeling down and holding a camera on a tripod. He is wearing jeans and a black jacket. The woman is standing to the right. She is
Denny Henry, Mike Guinto, and Katie Mellos setting up a remote camera to photograph the PACE launch next to SLC-40 at Kennedy Space Center in Cape Canaveral, Florida. Image Credit: Desiree Stover

What was your favorite part of launch?

The whole photography team was there, but none of us had ever photographed a launch before. We set up a bunch of remote cameras, which we’ve never done before, and borrowed some really long lenses to photograph it. It was a learning experience, in a good way. We had a lot of fun learning how to capture this very specific event, and it was great to see all those years of hard work blasted off into the sky.

What is your favorite color and why?

My favorite color is green. I’m not sure why it’s my favorite color. I have some green shoes, and also I feel like it’s just not as common of a color for some things to be.

A man stands centered in the image wearing glasses, a green crewneck sweatshirt, and a baseball cap. He holds four woodworking tools - clamps - in his left hand. In his right hand he has another clamp which is resting on his shoulder and extends behind his head. The clamps are orange, black, and silver colored in their pieces.
Denny Henry with a bunch of woodworking clamps. Image Credit: Jackie Henry

What is a fun fact about yourself?

I do a bit of woodworking. I usually make small things like cutting boards and small boxes. My big pandemic project – that is still ongoing – is to totally redo our kitchen. I have rebuilt all the cabinets from scratch. I think I maybe bit off a bit more than I can chew with that project, since it’s been a couple of years and I’m probably only 50% of the way at this point.

What advice would you give to aspiring students looking to get where you are today?

Photography is a tough career. There’s a lot of people who want to do it, and there are not that many jobs. How well they do and where they end up is not a reflection on the quality of a photographer. In saying that, you have to love doing it.

The image primarily is focused on the sky, which is dark and cloudy at night. There is a streak of light that starts near the bottom left corner and rises up to the center top of the image. The clouds surrounding this streak glow a brighter white than those that aren't illuminated by the light. The light is also reflected off of the ocean, which is seen in a small strip at the bottom of the image.
Another of Denny’s favorite images that he took of PACE. A long exposure photograph of NASA’s PACE (Plankton, Aerosol, Cloud, ocean Ecosystem) spacecraft, atop a SpaceX Falcon 9 rocket, as it successfully lifts off from Space Launch Complex 40 at Cape Canaveral Space Force Station in Florida at 1:33 a.m. EST Thursday, Feb. 8. Image Credit: Dennis Henry

Header image caption: Denny Henry posing in front of the PACE spacecraft in the cleanroom at NASA’s Goddard Space Flight Center in Greenbelt, MD. Image credit: Katie Mellos

By Erica McNamee, Science Writer at NASA’s Goddard Space Flight Center

The Journey of a Carbon Atom: From Space, NASA’s PACE Mission Detects Carbon in the Sky, Land, and Sea

Whether in plants or animals, greenhouse gases or smoke, carbon atoms exist in various compounds as they move through a multitude of pathways within Earth’s system. That’s why NASA’s Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission – scheduled to launch in January 2024 – was designed to peer down at Earth from space to see those many forms of carbon in a way no other satellite has done before by measuring colors not yet seen from the vantage point of space.

“PACE is standing on the shoulders of some giants, but previous and current satellites are limited in how many colors of the rainbow they can actually see,” said Jeremy Werdell, project scientist for the PACE mission at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

Although one of the primary goals of the mission is to measure the colors on the ocean surface, in the 420 miles (676.5 kilometers) between PACE in orbit and sea level are parts of the complex carbon web that the satellite will also be able to monitor.

The connection between major wildfires and the subsequent explosion of phytoplankton production is an example of the events NASA’s upcoming Plankton, Aerosols, Clouds, and ocean Ecosystem (PACE) mission will help investigate. PACE’s suite of instruments will allow scientists to get a clearer picture of carbon as it links land use and fires, atmospheric aerosols and marine communities. Credit: NASA’s Goddard Space Flight Center

Atmosphere

From PACE’s location in space, one of the nearest forms of carbon to detect could be the wispy plumes of smoke and ash rising into the atmosphere from fires. Carbon is a key building block of much life on Earth, including plant life. When burned, the vegetation’s carbon-based molecules transform into other compounds, some of which end up as ash in these plumes.

The instruments on PACE will be able to monitor these smoky clouds, as well as other atmospheric aerosol particles, measuring their characteristics including the relative amount of smoke in different places. Combinations of these measurements made by PACE’s two companion polarimeter instruments, SPEXone and the Hyper-Angular Rainbow Polarimeter-2 (HARP2), and the detailed color measurements of the smoke made by the Ocean Color Instrument (OCI) will also help scientists identify what was burnt.

“Each instrument brings something different,” said Andy Sayer, PACE’s project science lead for atmospheres at NASA Goddard. “Putting them all together though, you’re getting the most information.” Sayer is also a senior research scientist for the University of Maryland Baltimore County.

These measurements help scientists understand more about the balance between the incoming energy from the Sun, the outgoing energy from Earth, and where it may be absorbed in between by things in the atmosphere like these smoke plumes. Even at a local level, PACE can provide information about how smoke affects air quality, impacting communities that may be near fires.

Land

Peering through the smoke particles and other aerosols, PACE can also tell us about the health of terrestrial plants and trees. Even after a devastating wildfire, fresh green plant life begins to grow and thrive. With more spectral bands and colors to see from the upcoming satellite, scientists will be able to understand what kinds of plants are recovering from fires over the years.

“In a time where we’re experiencing unprecedented climate change, we need to be able to understand how global vegetation responds to its environment,” said Fred Huemmrich, research associate professor at the University of Maryland, Baltimore County, and a member of the PACE science and applications team.

PACE will be able to monitor the different shades of colors in vegetation, and plant color can be an indicator of health. Just as house plants begin to fade to yellow if they haven’t been watered enough, plant life around the globe changes color as it experiences stress. Healthy plants take up carbon in the form of carbon dioxide as part of photosynthesis, while unhealthy plants that can’t complete photosynthesis leave the carbon dioxide roaming around the atmosphere. Given that carbon dioxide is a greenhouse gas, these measurements also play a significant role in understanding climate change in greater detail.

By measuring a full spectrum of color, PACE will view tiny changes in pigment to detect how plants are responding to stressors, helping scientists learn whether they are utilizing the surrounding carbon or not. Previously, these colors were primarily viewed in field studies of specific areas. Stressors like droughts were inferred using weather data, but covering large expanses was difficult.

“For the first time, we’ll really be able to look at changes in the health of plants over the globe,” Huemmrich said. “It will dramatically improve our understanding of how ecosystems function and how they respond to stress.”

Ocean

From plants on land to organisms in the ocean, PACE will view the expanses of water on Earth to measure phytoplankton – the P in its name. With its ability to measure a wide spectrum of colors, PACE will now not only be able to see more across the surface of the ocean but will also help scientists differentiate between phytoplankton species.

“It’s like you were making a painting with really coarse brushes, and now you have thin, fine brushes that help explain so much more in greater detail,” said Ivona Cetinić, an oceanographer in the Ocean Ecology Lab at NASA Goddard.

Phytoplankton, small organisms that live on the surface of the ocean, play a critical role in the food chain and the global carbon cycle. Each type of phytoplankton provides a different pathway in that expansive web of routes that carbon can take, all depending on the characteristics of the plankton. One pathway may lead to the carbon becoming food for a larger species, while another may lead to carbon becoming waste, sinking deeper into the ocean.

Scientists conducting field work have found that types of phytoplankton vary slightly in color and have identified these phytoplankton on small scales. PACE’s ability to measure a full spectrum of color will help scientists tell the difference between phytoplankton on a global scale by seeing more of these colors, deepening the understanding of carbon pathways and quantities.

Though one of PACE’s key goals is to view the ocean, its line of sight looks over the atmosphere and land as well. With these expansive observations, and the massive quantities of data collected, PACE provides the ability to see in what ways the atmosphere, land, and ocean are connected, including with the complex web of carbon pathways. 

“I’m energized for this opportunity for discovery that this observatory is offering,” Werdell said. “I have every expectation the world is going to do great things with these data.”

By Erica McNamee, Science Writer at NASA’s Goddard Space Flight Center

Observatory, assembled!

The Ocean Color Instrument (OCI) is integrated onto the PACE spacecraft in the cleanroom at Goddard Space Flight Center. Credit: NASA’s Goddard Space Flight Center.

The PACE satellite now has all three of its scientific instruments attached to the spacecraft, as the integration crew bolted the Ocean Color Instrument into place with its two polarimeter neighbors.

With the assembly completed Nov. 21 at NASA’s Goddard Space Flight Center, the team will now be working on the electronic and other connections between the different components of the satellite, then putting the complete observatory through tests to make sure it can work in the harsh environment of space.

By Kate Ramsayer, Science Writer at NASA’s Goddard Space Flight Center

NASA’s PACE Mission Undergoes Milestone Testing

NASA’s PACE mission, which will provide a major boost to scientists studying Earth’s atmosphere and ocean health, completed a milestone test in October at the agency’s Goddard Space Flight Center in Greenbelt, Maryland.

The Ocean Color Instrument (OCI) on the Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission passed thermal vacuum tests to ensure it can withstand the harsh space environments.

As we prepare the Plankton, Aerosol, and cloud Ecosystem satellite for launch, we’re gathering all the ingredients, um…instruments, and baking ourselves a fresh new satellite. Credit: NASA’s Goddard Space Flight Center/Scientific Visualization Studio. Video descriptions available. 

PACE will view the atmosphere and ocean surface from space. While highly useful for studying atmospheric aerosols, OCI is specifically designed to look for small aquatic organisms called phytoplankton that can be so numerous they influence the colors of the ocean. Phytoplankton play a large role in the ocean ecosystem — not only are they food sources for larger species, but they also convert carbon dioxide into organic matter through photosynthesis, playing an active role in moving carbon from the atmosphere into the ocean.

The PACE mission will help scientists learn more about the relationships between phytoplankton and the surrounding environment by measuring how light reflects off the ocean and through the atmosphere. Scientists can see these organisms in the ocean using satellites, but currently can’t differentiate the phytoplankton by type easily. Identifying types of phytoplankton help scientists to detangle some of the complex ecological systems in the oceans.

“When you look down at the ocean, you can see phytoplankton there and for the first time, with PACE, the scientists will be able to see what type of phytoplankton there are from space,” said Gary Davis, mission systems engineer at Goddard for the PACE mission. “Hopefully this mission will be able to communicate the importance of ocean health and the health of plankton to the whole world.”

To ensure the satellite is ready to gather this data, engineers put the satellite through, well, its paces. The thermal vacuum test that was just completed reduces atmospheric pressure as close to the vacuum of space as possible and then cycles through a wide range of temperatures. During the sunlit part of a spacecraft’s orbit, it can get very hot, up to approximately 50 degrees Celsius (122 degrees Fahrenheit); at other parts of the orbit, zero solar exposure means extremely low temperatures, as low as -90 degrees Celsius (-130 degrees Fahrenheit).

OCI, which was built at Goddard, can measure light in a multitude of colors, far more than previous satellites that share its frequent global coverage. Light variation by wavelength, the character of light by which it is defined, provides the color we see. OCI can detect a continuous spectrum of different wavelengths of light, and can even see colors beyond what the human eye can detect. By detecting more wavelengths, the instrument will allow scientists to tell the difference between types of phytoplankton from space. This is helpful in understanding the pathways of the carbon cycle in the atmosphere, land, and ocean, and characterizing the phytoplankton as harmful or helpful.

“OCI is really a stretch of the state of the art of what we can do right now,” said Davis. “It’s probably the most advanced thing we have on the observatory.”

Former ocean-observing satellites had the ability to measure light at a small set of wavelengths through the development of multi-spectral instruments. OCI has the ability to measure color continuosly at many ultraviolet, visible, and near infrared wavelengths, also known as hyperspectral imaging.

The previous missions can be imagined as a regular 8-color box of crayons, said Jeremy Werdell, project scientist for the PACE mission. Though still highly valuable for creating a complete picture, there are gaps in between the shades of colors. For PACE, OCI can be imagined as a 128-color box of crayons, filling in those gaps using smaller and continuous intervals of wavelengths.

“With all of the colors of the rainbow here, most of us don’t know what we’re going to discover, because we’ve never had that chance on global scales,” Werdell said. “It’s the only mission planned at NASA or elsewhere that provide global hyperspectral, full colors of the rainbow everywhere, everyday.”

When light from the sun reflects off the ocean, that light has already traveled from the sun, through the atmosphere – clouds and aerosols that compose Earth’s atmosphere – and water before it reaches the plankton in the ocean. The light then bounces off the plankton and travels back through the water and atmosphere again. The light that makes its way through all those stages can tell a story through color but still needs to be analyzed and accounted for any atmospheric effects, which is where the polarimeters on PACE come into play.

The Hyper-Angular Rainbow Polarimeter 2 (HARP2) also recently completed TVAC testing, earlier in September. The instrument is one of two multi-angle polarimeters on PACE, which act as polarized sunglasses for the spacecraft, measuring how light bends as it travels through the water droplets, clouds, and aerosols in Earth’s atmosphere, informing scientists more about their physical properties, as well as providing another source of color measurements. HARP2 was built at the University of Maryland, Baltimore County.

SPEXone, the other multi-angle polarimeter, was built in the Netherlands by engineers from SRON Netherlands Institute for Space Research, Airbus Netherlands and NASA. Each of the three instruments will be integrated into the spacecraft as they complete their individual tests – and in fact, OCI was just lifted onto the spacecraft on November 21.

“We have an observatory!” said Werdell.

As the timeline of events for PACE ticks on, the days are being counted down, all leading to the launch scheduled for early 2024.

For more information on PACE, visit https://pace.gsfc.nasa.gov.

By Erica McNamee, Science Writer at NASA’s Goddard Space Flight Center